Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BMS 250 test 2 > Entire semester Together > Flashcards

Entire semester Together Flashcards

(688 cards)

Start Studying
1
Q

What is an allergy?

A

A heightened sensitivity to a foreign protein called an allergen, elicited through ingestion, contact, or inhalation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define rhinitis.

A

Eosinophilic inflammation of the nasal mucosa and paranasal sinuses resulting from an IgE-mediated reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List the manifestations of allergic rhinitis.

A
  • Nasal congestion
  • Obstructed airflow
  • Increased mucous production
  • Drainage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the initial phase of allergic rhinitis onset in atopic individuals?

A

Sensitization followed by subsequent reexposure to a designated allergen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What role do antigen-presenting cells play in allergic rhinitis?

A

They assimilate a low-dose exposure of the antigen and present it to helper T lymphocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What cytokines are produced by activated helper T lymphocytes?

A
  • IL-4
  • IL-5
  • IL-13
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What triggers mast cell activation in allergic rhinitis?

A

The binding of specific antigens to IgE antibodies affixed to mast cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the hallmark acute symptoms of allergic rhinitis?

A
  • Rhinorrhea
  • Nasal congestion
  • Nasal irritation
  • Sneezing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the role of histamine in allergic rhinitis?

A

Stimulates sensory nerve endings of the Vth nerve, eliciting sneezing and prompts mucous gland secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When does the late phase response of allergic rhinitis occur?

A

4-6 hours after antigen stimulation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the duration of symptoms in the late phase of allergic rhinitis?

A

Symptoms can last for about 18-24 hours.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What cells predominantly infiltrate the affected area during the late phase?

A
  • T lymphocytes
  • Basophils
  • Eosinophils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the significance of cytokines in the late phase response?

A

They orchestrate the release of mediators and facilitate the infiltration of inflammatory cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are some well-known risk factors for allergic rhinitis?

A
  • Atopy
  • Asthma
  • Eczema
  • Other allergies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does parental history factor into allergic rhinitis risk?

A

A parental history of allergic rhinitis, asthma, and pollen allergies is a documented risk factor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are common food allergens that cause allergic rhinitis in infancy and childhood?

A
  • Milk
  • Eggs
  • Soy
  • Wheat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What role does the gut microbiota play in allergic disease pathogenesis?

A

The composition of the gut microbiota influences immune function and may play a role in allergic diseases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

List the four main classes of microbiomes.

A
  • Bacteroidetes
  • Actinobacteria
  • Firmicutes
  • Proteobacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is dysbiosis?

A

An imbalance in gut microbiota associated with atopy and allergic disorders.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can dysbiosis affect allergic rhinitis?

A

It can disrupt Th1/Th2 homeostasis, affecting immunotolerance and increasing the risk of allergic rhinitis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Fill in the blank: Probiotics may be one of the options clinicians may use to improve their patients’ quality of life since treating AR is _______.

A

[challenging]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the gut microbiome diversity in allergic rhinitis (AR) patients?

A

Reduced gut microbiome diversity

Increased Bacteroidetes; decreased Actinobacterium, Proteobacterium, and Escherichia coli.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are potential biomarkers associated with allergic rhinitis?

A

Increased:
* S. Shigella
* E. coli
* Parabacteroides
* Lachnoclostridium
* Dialister
Decreased:
* Oxalobacter
* Clostridiales

These markers indicate shifts in microbial populations in AR patients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which microbiome metrics are observed in AR patients?

A

Lower diversity indices (Chao1 and Shannon)
* More abundant Bacteroidetes
* Reduced Firmicutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How is symptom severity linked to gut microbiome composition in AR?
Symptoms linked to levels of Butyrococcus and Eisenbergiella
26
What are common symptoms of allergic rhinitis?
* Clear and watery nasal discharge * Nasal congestion * Postnasal drip * Itching of the nose, throat, and eyes
27
What physical examination findings are consistent with allergic rhinitis?
* Mouth breathing * Frequent sniffling/throat clearing * Transverse supra-tip nasal crease * Allergic shiners (dark circles under the eyes)
28
What findings are observed during anterior rhinoscopy in AR patients?
* Swelling of the nasal mucosa * Thin, clear secretions * Bluish hue of inferior turbinates * Cobblestoning of the nasal mucosa
29
What is seasonal allergic rhinitis?
Symptoms can occur or increase due to pollination of specific plants
30
What triggers perennial allergic rhinitis?
* Dust mites * Animal dander * Mold spores * Cockroaches * Food allergens * Infection * Nonspecific irritants
31
What are the classifications of allergic rhinitis based on symptom frequency?
* Intermittent: < 4 days/week or < 4 weeks’ duration * Persistent: > 4 days/week or > 4 weeks’ duration
32
What are common complications of allergic rhinitis?
* Adenoid hypertrophy * Eustachian tube dysfunction * Chronic rhinosinusitis * Nasal polyps * Sleep disruption * Learning disturbances
33
What are the symptoms of nonallergic rhinitis?
* Nasal obstruction * Clear rhinorrhea * Sneezing and itchy, watery eyes are not common
34
What characterizes viral rhinitis?
Accompanied by other viral illness symptoms like headaches, malaise, body aches, and coughing
35
What is occupational rhinitis?
Caused by exposure to indoor and outdoor pollutants like dust, ozone, and cigarette smoke
36
What is vasomotor rhinitis?
A common form of nonallergic rhinitis triggered by environmental conditions
37
What is the primary neurotransmitter involved in mucus secretion during vasomotor rhinitis?
Acetylcholine
38
What is nonallergic rhinitis with eosinophilia (NARES)?
A syndrome with nasal obstruction and congestion, severe exacerbations, and marked eosinophilia (> 25%)
39
What causes rhinitis medicamentosa?
Overuse of topical nasal decongestants like oxymetazoline and phenylephrine
40
What physiological changes occur during pregnancy that contribute to nasal congestion?
* Increased estrogen levels * Increased hyaluronic acid in nasal tissue * Decreased nasal cilia * Increased mucous glands
41
What are some systemic diseases that can cause chronic rhinosinusitis?
* Granulomatosis with polyangiitis * Aspirin-exacerbated respiratory disease (AERD) * Cystic fibrosis * Immunodeficiency * Primary ciliary dyskinesia
42
What defines chronic rhinosinusitis (CRS)?
Inflammation of the nasal cavity and paranasal sinuses lasting more than 12 weeks
43
What are common clinical features of chronic rhinosinusitis?
* Purulent drainage * Facial/dental pain * Nasal obstruction * Hyposmia * Headaches * Fatigue
44
What are the signs of infection severity in sinusitis?
Fever is an important indicator despite having only 50% sensitivity
45
What findings should be observed during nasal endoscopy for sinusitis diagnosis?
* Purulent drainage * Polyps * Polypoid changes in the mucosa * Edema or erythema
46
What are nasal polyps?
Benign inflammatory and hyperplastic growths from the sinonasal mucosa ## Footnote They usually arise from the lateral nasal wall or the ethmoid recess.
47
Where do nasal polyps typically appear?
In the nose or sinuses
48
What types of cells are found in nasal polyps?
* Plasma cells * Lymphocytes * Eosinophils * Mucous glands
49
What is the primary cause of nasal polyps?
T-helper 2 (Th2) cell-driven eosinophilia and IgE inflammation
50
What factors can contribute to the formation of nasal polyps?
* Allergic environment * Age-related anatomical changes * Impaired clearance of irritants
51
What are common clinical features of nasal polyposis?
* Nasal obstruction * Facial congestion * Decreased sense of smell * Rhinorrhea
52
What examination techniques are used to diagnose nasal polyposis?
* Anterior rhinoscopy * Nasal endoscopy
53
What is the nasal septum?
A wall composed of osteocartilaginous tissue that separates two nasal cavities
54
What can asymptomatic minor deviations of the nasal septum indicate?
Normal developmental variations
55
What conditions can nasal septal deviation lead to?
* Headaches * Rhinosinusitis * Obstructive sleep apnea
56
What is acute pharyngotonsillitis commonly caused by?
Viruses (most common) or bacteria
57
What are common symptoms of acute pharyngotonsillitis?
* Fever * Malaise * Odynophagia * Dysphagia * Foul breath
58
What percentage of acute pharyngotonsillitis cases are caused by viral infections?
Approximately 70 to 85%
59
Which viruses are common pathogens in acute pharyngotonsillitis?
* Adenoviruses * Rhinoviruses * Coronaviruses * Epstein-Barr viruses * Cytomegaloviruses * Coxsackieviruses * Herpes simplex viruses * Influenza viruses
60
What is a hallmark symptom of Epstein-Barr virus (EBV) infection?
Lymphoid hypertrophy, especially in posterior nodes
61
What is acute retroviral syndrome associated with HIV?
A manifestation that can cause pharyngitis
62
What is the main cause of acute bacterial pharyngotonsillitis in children?
Group A beta-hemolytic streptococcus (GABHS)
63
What are the complications associated with acute streptococcal pharyngotonsillitis?
* Scarlet fever * Acute rheumatic fever * Poststreptococcal glomerulonephritis * Pediatric autoimmune neuropsychiatric disorder associated with GABHS
64
What symptoms are associated with scarlet fever?
* Erythematous rash * Fever * Lymphadenopathy * Dysphagia * Erythematous tonsils
65
What is a peritonsillar abscess?
A consequence of infection spreading from the superior pole of the tonsil
66
What pathogens commonly cause peritonsillar abscess?
* GABHS * Staph aureus * Haemophilus influenza * Prevotella * Porphyromonas * Fusobacterium
67
What are the clinical presentations of peritonsillar abscess?
* Severe pain * Odynophagia * Muffled voice * Dysphagia
68
What can cause parapharyngeal space abscesses?
Infections from peritonsillar abscesses or tonsils spreading through the superior constrictor muscle ## Footnote This abscess is located between the superior constrictor muscle and the deep cervical fascia.
69
What symptoms can result from parapharyngeal abscesses?
Trismus and decreased neck range of motion due to inflammation of adjacent muscles ## Footnote The tonsil and pharyngeal walls may be displaced medially.
70
What happens if a parapharyngeal abscess is untreated?
It can spread down the carotid sheath into the mediastinum.
71
What is a retropharyngeal abscess?
An infection in the lymph nodes of the retropharyngeal space or from a peritonsillar abscess ## Footnote More common in children.
72
What are the symptoms of a retropharyngeal abscess?
Fever, dysphagia, muffled speech, noisy breathing, stiff neck, cervical lymphadenopathy
73
What type of streptococci can cause Non-Group A Streptococcal Pharyngitis?
Group C and G streptococci
74
How does Non-Group A Streptococcal Pharyngitis compare to Group A?
Similar presentation but usually less severe symptoms
75
What causes pharyngeal diphtheria?
Corynebacterium diphtheriae
76
What characterizes the disease caused by Corynebacterium diphtheriae?
A grayish, tightly adherent pseudomembrane covering tonsils and extending to nares, uvula, soft palate, and pharynx
77
What is a potential risk associated with diphtheria?
Airway compromise and cardiac/neurotoxicity from exotoxins
78
Which pathogens can cause tonsillar infections related to sexually transmitted diseases?
Neisseria gonorrhoeae and Treponema pallidum
79
What is a common presentation of gonococcal infections?
Exudative pharyngitis
80
What are the symptoms of primary oral syphilis?
Painless chancre on lips, buccal mucosa, or oropharynx
81
What can occur in secondary syphilis patients?
Oropharyngeal and tonsillar ulcers and bilateral tonsillar hypertrophy
82
What causes oropharyngeal candidiasis?
Overgrowth of Candida albicans
83
What do the plaques of oropharyngeal candidiasis resemble?
White cottage cheese-like plaques
84
What characterizes recurrent acute tonsillitis?
Recurrent episodes of acute tonsillitis with complete recovery between episodes
85
What is the typical bacterial flora in children with recurrent tonsillitis?
Polymicrobial, including Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae
86
What defines chronic tonsillitis?
Sore throat lasting at least three months, tonsillar inflammation, halitosis, and tender cervical adenopathy
87
What are tonsilloliths?
Microbial biofilms that form within tonsillar crypts
88
What can cause aphthous ulcers?
Human herpesvirus 6, although this remains uncertain
89
What are the characteristics of minor aphthous ulcers?
Smaller than 1 cm in diameter and heal in 10-14 days
90
What conditions can present with large or persistent ulcerative stomatitis?
Erythema multiforme, drug allergies, acute herpes simplex, pemphigus, pemphigoid, epidermolysis bullosa acquisita, bullous lichen planus, Behçet disease, IBD
91
What is the most common pathogen causing supraglottitis?
Haemophilus influenzae type B (HIB)
92
What are the clinical features of supraglottitis?
Fever, difficulty breathing, severe odynophagia, drooling, irritability, leaning forward, muffled voice, inspiratory stridor
93
What is the primary cause of laryngitis?
Viral upper respiratory infections
94
What are common bacteria involved in bacterial laryngitis?
S pneumoniae, H influenzae, M catarrhalis
95
What noninfectious causes can lead to laryngitis?
Vocal trauma, inhalation injuries, allergies, gastroesophageal reflux disease, asthma, pollution
96
What characterizes bacterial tracheitis?
Secondary bacterial colonization following a viral respiratory tract infection
97
What is the most common pathogen isolated in bacterial tracheitis?
Staphylococcus aureus
98
What defines obstructive lung diseases?
Impaired ability of air to leave the alveoli during expiration, clinically defined by decreased FEV1/FVC ratio
99
What are examples of obstructive lung diseases?
* Bronchial Asthma * Chronic Obstructive Pulmonary Disease * Chronic Bronchitis * Emphysema * Bronchiectasis
100
What defines restrictive lung diseases?
Reduced total lung capacity and reduced FEV1/FVC ratio
101
What are examples of restrictive lung diseases?
102
What characterizes bronchial asthma?
Episodic airway obstruction, airway hyperresponsiveness, and inflammation
103
What is the heritable predisposition percentage for asthma?
25–80%
104
What triggers bronchoconstriction in asthma?
* Allergens * Infections of upper airways * Inhalatory irritants * Anxiety * Cold air * Physical activity * Gastroesophageal reflux * Drugs (e.g., nonsteroidal anti-inflammatory drugs)
105
What are the two older classifications of asthma?
Extrinsic and intrinsic
106
What are the two newer classifications of asthma?
Allergic asthma and nonallergic asthma
107
What is allergic asthma also known as?
Atopic asthma
108
What is nonallergic asthma also referred to as?
Nonatopic asthma
109
What are some causes of allergic asthma?
* Pollens * Dust * Drugs
110
What is the mechanism of allergic asthma?
Type I hypersensitivity reaction
111
Which demographic does allergic asthma occur more frequently in?
Children
112
What associated conditions may patients with allergic asthma have?
* Hay fever * Eczema
113
What triggers nonallergic asthma?
* Exercise * Cold air * Drugs * Gastroesophageal reflux * Viral infections
114
What is a hallmark of asthma?
Airway hyperresponsiveness
115
What are the two components of airway hyperresponsiveness?
* Functional component * Structural component
116
What occurs during the early stage of asthma?
Mediators promoting bronchoconstriction
117
What mediators are involved in the early stage of asthma?
* Leukotrienes C4, D4, and E4 * Histamine * Prostaglandin D2 (PGD2)
118
What happens in the late stage of asthma?
Release of enzymes by eosinophils and neutrophils
119
What is a significant morphological change in asthma?
Smooth-muscle constriction and mucus
120
What are the pathological features of asthma?
* Airway lumen is reduced * Thickening of the submucosa * Edema and cellular infiltration
121
What is the classic triad of clinical symptoms in asthma?
* Wheezing * Dyspnea * Cough (night-time)
122
What is status asthmaticus?
A prolonged asthmatic attack which can be fatal
123
What is the definition of Chronic Obstructive Pulmonary Disease (COPD)?
Preventable and treatable disease with airflow limitation that is not fully reversible
124
What is the most significant risk factor for COPD?
Smoking
125
What are the four interrelated events in the pathogenesis of COPD?
* Inflammatory and immune cell recruitment * Proteinases damage the extracellular matrix * Structural cell death through oxidant-induced damage * Disordered repair of elastin
126
What is the typical spirometry finding in late asthma?
Low peak expiratory flow (PEF) and decreased FEV1/FVC
127
What occurs to arterial blood gases during an exacerbation of asthma?
CO2 is low secondary to hyperventilation
128
What are eosinophilia and its relevance in asthma?
Increased eosinophils are often associated with asthma inflammation
129
Fill in the blank: The early stage of asthma is characterized by _______.
[mediators promoting bronchoconstriction]
130
True or False: Nonallergic asthma is associated with elevated IgE levels.
False
131
What triggers airway narrowing in asthma?
Continued or additional exposures and triggers
132
What is the definition of Chronic Bronchitis?
Productive cough for at least 3 months in 2 consecutive years.
133
What is the pathogenesis of Chronic Bronchitis?
Cigarette smoking – airway irritation - increased production of mucus - hyperplasia of mucous-secreting glands.
134
What are the types of Chronic Bronchitis?
* Simple * Obstructive * Asthmatic
135
What does the lumen contain in Small Airway Pathology in COPD Chronic Bronchitis?
Mucus and inflammatory debris.
136
What is Goblet cell metaplasia?
Transformation of airway epithelium to goblet cells, associated with mucus overproduction.
137
What happens to the submucosal layer in Chronic Bronchitis?
Increased thickness due to an increase in fibrous tissue and inflammatory cells.
138
What is a key characteristic of Emphysema?
Dilation of airspaces.
139
What are the histological features of Emphysema?
Loss of pulmonary parenchyma and greatly increased size of the airspaces.
140
What are the two types of Emphysema?
* Centriacinar emphysema (smoking) * Panacinar emphysema (α1-antitrypsin deficiency)
141
What is the definition of Bronchiectasis?
An irreversible airway dilation that involves the lung in either a focal or a diffuse manner.
142
What are the two components required for the pathogenesis of Bronchiectasis?
* Infection * Obstruction
143
What is the difference between focal and diffuse Bronchiectasis?
* Focal: bronchiectatic changes in a localized area of the lung. * Diffuse: widespread bronchiectatic changes throughout the lung.
144
What is the 'Vicious Cycle Hypothesis' in Infectious Diffuse Bronchiectasis?
Susceptibility to infection leads to chronic inflammation and ongoing propagation of the infectious/inflammatory cycle.
145
What are common complications of Bronchiectasis?
* Recurrent infections * Hemoptysis
146
What are the general characteristics of Restrictive Lung Diseases?
* Acute: ARDS - Diffuse Alveolar Damage * Chronic: Idiopathic Pulmonary Fibrosis, Sarcoidosis, Pneumoconioses
147
What characterizes Acute Restrictive Lung Disease?
Disease developing over a short time period (minutes to days) secondary to a major systemic insult.
148
What is the clinical term for acute restrictive lung disease?
Acute respiratory distress syndrome (ARDS).
149
What are the stages of Diffuse Alveolar Damage?
* Exudative stage * Proliferative stage * Fibrosis
150
What are the main causes of Diffuse Alveolar Damage?
* Severe pulmonary infection * Aspiration * Sepsis * Severe trauma with shock
151
What is the pathophysiology of symptoms in Chronic Restrictive Lung Disease?
Chronic diffuse lung injury, inflammation, and fibrosis leading to impaired gas exchange.
152
What are the histological categories of Idiopathic Interstitial Pneumonia?
* Usual interstitial pneumonia (UIP) * Nonspecific interstitial pneumonia (NSIP) * Organising pneumonia (OP) * Diffuse alveolar damage (DAD) * Desquamative interstitial pneumonia (DIP) * Respiratory bronchiolitis (RB) * Lymphocytic interstitial pneumonia (LIP)
153
What is the prognosis for Non-Small Cell Lung Cancer?
Accounts for 80% of all lung cancers.
154
What are the three main subtypes of Non-Small Cell Lung Cancer?
* Adenocarcinoma * Squamous cell carcinoma * Large cell carcinoma
155
What is the most common subtype of lung cancer in North America?
Adenocarcinoma.
156
What is a characteristic of Squamous Cell Carcinoma?
Characterized histologically by the presence of keratin pearls.
157
What is the prognosis for Large Cell Carcinoma?
10% 5-year survival.
158
What is the peak age for lung cancer?
Between 60 and 70 years.
159
What percentage of lung cancers does Small Cell Lung Cancer account for?
13.8%
160
Is Small Cell Lung Cancer more common in men or women?
Slightly more common in women
161
What is Small Cell Lung Cancer strongly associated with?
Smoking
162
Where is Small Cell Lung Cancer often located?
Centrally or in the hilum
163
What type of cells do Small Cell Lung Cancers develop from?
Neuroendocrine cells
164
How does the growth and spread of Small Cell Lung Cancers compare to non-small cell lung cancers?
They grow and spread more quickly
165
What is the 5-year survival rate for Small Cell Lung Cancer?
5%
166
What is the single most important predictor of prognosis in lung cancer?
Tumor stage
167
What does the TNM staging system stand for?
* T: tumor size and extent of local and/or regional spread * N: spread of tumor to regional or distant lymph nodes * M: presence of distant metastases or involvement of the pleural fluid
168
What characterizes Stage I lung cancer?
Small tumor size and absence of lymph node involvement and metastases
169
What determines Stages II & III of lung cancer?
Extent of regional lymph node involvement
170
What defines Stage IV lung cancer?
Any tumor with distant metastasis
171
At initial diagnosis, what percentage of patients have localized lung cancer?
20%
172
What is the most common presenting symptom of lung cancer?
Cough
173
In what percentage of cases is lung cancer diagnosed in asymptomatic patients as an incidental finding?
7-10%
174
What are common clinical features due to the primary tumor in lung cancer?
* Cough * Hemoptysis * Dyspnea * Wheezing * Atelectasis * Postobstructive pneumonia
175
What are the features of Pancoast tumors?
* Shoulder and upper back pain * Horner’s syndrome * Severe arm and shoulder pain
176
What syndrome can occur due to obstruction of the superior vena cava in lung cancer?
Superior vena cava syndrome
177
What are common symptoms of distant metastasis in lung cancer?
* Weight loss * Bone pain * Altered sensation * Headache * Jaundice
178
What are paraneoplastic syndromes?
Clinical syndromes involving nonmetastatic systemic effects that accompany a cancer
179
What are the two most common causes of paraneoplastic syndromes?
* Production and release of physiologically active substances by the cancer * Altered immune response
180
What is hypercalcemia due to in lung cancer?
Ectopic production of a parathyroid hormone related peptide
181
What is the lifetime risk of developing lung cancer in smokers?
12-17%
182
What substance in tobacco smoke is known to cause DNA damage?
Polyaromatic hydrocarbons
183
What is the most common occupational risk factor for lung cancer?
Exposure to asbestos
184
What percentage of lung cancers are associated with radon exposure?
10%
185
What are activating mutations in the EGFR gene associated with?
Adenocarcinomas
186
What is the prognosis for typical carcinoids after surgery?
90% 5-year survival
187
What type of cancer is mesothelioma?
Cancer of the pleural lining
188
What is the main cause of mesothelioma?
Asbestos exposure
189
What percentage of lung cancers are carcinoid tumors?
2-3%
190
What are the two subtypes of carcinoid tumors?
* Typical carcinoid * Atypical carcinoid
191
What is the prognosis for atypical carcinoids after surgery?
60% 5-year survival
192
What is the mean pulmonary arterial pressure used to diagnose pulmonary hypertension?
>20 mmHg
193
What is primary pulmonary hypertension associated with?
Mutations of BMPR2, ALK1, and endoglein
194
What is the driving pressure in the pulmonary artery?
10 mm Hg
195
What are the common sites for lung metastasis?
* Edges of the lungs * Lower lobes
196
What are common cancers that metastasize to the lung?
* Bladder cancer * Breast cancer * Colorectal cancer * Kidney cancer * Melanoma * Sarcomas * Testicular
197
What is loose collagen?
Medium-sized vein obliterated by loose connective tissue - an organized thrombus
198
What is Pulmonary Arterial Hypertension (PAH) WHO Group I?
Primary Pulmonary Hypertension: Rare precapillary disorder caused by increased pulmonary arterial tone
199
What are the potential causes of idiopathic PAH?
May be idiopathic, hereditary with mutations in BMPR2, ALK1, endoglein, or due to drugs/toxins
200
What is the effect of drugs or toxins on PAH?
Cause endothelial dysfunction, increase pulmonary arterial tone, promote vascular remodeling, leading to increased PVR
201
What is idiopathic PAH (IPAH)?
A progressive disease that leads to right heart failure and early mortality
202
How does the prevalence of IPAH differ between genders?
Women to men by ~3.1-fold; more common in women in their 20s and 30s
203
How does the prognosis of PAH differ between men and women?
Men have more severe hemodynamics at diagnosis and a less favorable prognosis compared to women
204
What is the impact of pathologic changes on pulmonary arterial compliance?
Results in a progressive increase in total pulmonary vascular resistance (PVR)
205
What must increase to preserve cardiac output in PAH?
Right ventricular work must increase
206
What is a common clinical symptom of PAH?
Insidious onset of dyspnea
207
What happens in end-stage PAH regarding cardiac output?
CO declines, leading to a decrease in mPAP
208
What are frequent extrapulmonary vascular manifestations of PAH?
Overactivation of neurohumoral signaling, renal failure, volitional muscle atrophy
209
What is the typical histological finding in severe pulmonary hypertension?
Plexiform lesions
210
What is the prognosis for patients with PAH under medical treatment?
5-year survival is about 30%
211
What treatment is often indicated for PAH?
Heart–lung transplantation
212
What is the definition of pulmonary edema?
An abnormal accumulation of fluid in the interstitial and alveolar spaces of the lung
213
Why is pulmonary edema considered an important complication?
It can be life-threatening and occurs in various heart and lung diseases
214
What are frequent causes of pulmonary edema?
215
What characterizes interstitial edema?
Increased lymph flow, widened lymphatics, perivascular and peribronchial engorgement
216
How does alveolar edema affect the lungs?
Fluid moves across the epithelium into the alveoli, preventing ventilation
217
What are common symptoms of pulmonary edema?
* Difficulty breathing (dyspnea) * Cough producing frothy sputum * Rapid, irregular heartbeat * Anxiety and restlessness * Cold, clammy skin * Wheezing or gasping for breath
218
What is the second most common cause of pulmonary hypertension?
Pulmonary Hypertension Associated with Lung Disease
219
What are some conditions associated with pulmonary hypertension in lung disease?
* Chronic obstructive pulmonary disease (COPD) * Interstitial lung disease * Sleep-related respiratory disorders
220
What percentage of COPD patients have mPAP >20 mmHg?
90%
221
What is the challenge with patients having primary lung disease and severe pulmonary hypertension?
They have poor clinical outcomes
222
What does venous thromboembolism (VTE) encompass?
Deep-venous thrombosis (DVT) and pulmonary embolism (PE) ## Footnote VTE can lead to cardiovascular death, chronic disability, and emotional distress.
223
Where do venous thrombi typically originate?
Deep veins of the lower extremities, but also the upper extremities, right side of the heart, and pelvic veins ## Footnote This is crucial for understanding the potential sources of thrombi.
224
What are the three components of Virchow's triad related to the pathogenesis of thrombi?
* Stasis of blood * Alterations in the blood coagulation system (hypercoagulability) * Abnormalities of the vessel wall (intimal injury) ## Footnote These factors contribute to the development of venous thromboembolism.
225
What is the most common autosomal dominant genetic mutation associated with hypercoagulability?
Factor V Leiden ## Footnote This mutation causes resistance to activated protein C, an important anticoagulant.
226
What is antiphospholipid antibody syndrome?
An acquired thrombophilic disorder that predisposes to both venous and arterial thrombosis ## Footnote It is not a genetic condition.
227
List three clinical risk factors for venous thromboembolism.
* Cancer * Obesity * Cigarette smoking ## Footnote Other factors include systemic arterial hypertension, COPD, chronic kidney disease, and long-haul air travel.
228
What is the definition of pulmonary embolism?
Thrombi form in large veins and travel to the lungs where they become lodged in and occlude the pulmonary circulation ## Footnote This condition is associated with significant morbidity and mortality.
229
What are the types of pulmonary emboli?
* Venous thrombi * Nonthrombotic emboli: fat, air, and amniotic fluid ## Footnote Understanding these types is essential for diagnosis and treatment.
230
True or False: Patients who suffer PE are more than twice as likely to have a future myocardial infarction or stroke.
True ## Footnote This highlights the interconnected risks of thromboembolic events.
231
What characterizes a massive (high-risk) pulmonary embolism?
Systemic arterial hypotension and extensive thrombosis affecting at least half of the pulmonary vasculature ## Footnote Symptoms may include dyspnea, syncope, hypotension, and cyanosis.
232
What is chronic thromboembolic pulmonary hypertension (CTEPH)?
Development of pulmonary hypertension after chronic thromboembolic obstruction of the pulmonary arteries ## Footnote The incidence following a single PE event is between 3 and 7%.
233
What is cor pulmonale?
Right ventricular failure due to excessively high pulmonary artery pressures ## Footnote It can be caused by pulmonary emboli, pulmonary vascular disease, or parenchymal disease.
234
What are the characteristics of vasculitis?
Inflammation of and damage to blood vessels, often leading to ischemia of the tissues supplied by the affected vessel ## Footnote The clinical manifestations vary based on the size, type, and location of the involved vasculature.
235
What is the hallmark of sarcoidosis pathology?
Noncaseating granulomatous inflammation ## Footnote This condition can affect any organ but most commonly targets the lungs and intrathoracic lymph nodes.
236
Fill in the blank: The finding of granulomas in sarcoidosis is not _______.
specific ## Footnote Differential diagnoses include mycobacterial and fungal infections, malignancy, and environmental agents.
237
What are the stages of sarcoidosis based on radiographic findings?
* Stage 0: No pulmonary sarcoidosis * Stage 1: Granulomas in lymph nodes only * Stage 2: Granulomas in lymph nodes and lungs * Stage 3: Granulomas in lungs only * Stage 4: Pulmonary fibrosis ## Footnote Each stage has distinct clinical implications.
238
What are common pulmonary function test results in sarcoidosis?
* Restrictive impairment with reduction in lung volumes * Reduction in diffusing capacity * Obstructive impairment in advanced disease ## Footnote Resting hypoxemia and exercise O2 desaturation are also typical.
239
What are the complications of asbestos exposure?
* Nonmalignant pleural manifestations * Asbestosis * Malignant mesothelioma * Lung cancer ## Footnote Asbestos exposure is linked to various serious health conditions.
240
What happens during initial macrophage alveolitis in asbestos exposure?
Most fibers are cleared, leaving the lungs unscarred ## Footnote If clearance is incomplete, fibrosis can ensue.
241
What are the malignant pleural manifestations related to asbestos exposure?
Malignant mesothelioma and lung cancer ## Footnote Asbestos exposure is linked to serious lung diseases.
242
What is asbestosis?
Interstitial pneumonitis and fibrosis resembling other forms of diffuse interstitial fibrosis ## Footnote Early lesions show discrete areas of fibrosis in respiratory bronchioles.
243
What characterizes the initial response to asbestos exposure?
Initial macrophage alveolitis, with most fibers cleared, leaving lungs unscarred ## Footnote Incomplete clearance can lead to fibrosis.
244
What are the signs and symptoms of asbestosis?
Dyspnea, bibasilar rales, restrictive ventilatory impairment ## Footnote Exposure duration and intensity should be assessed.
245
What is silicosis?
An occupational pulmonary hazard caused by free silica (SiO2) ## Footnote It is characterized by acute alveolitis and ground-glass appearance.
246
What is chronic silicosis?
Characterized by small rounded opacities in the upper lobes after 15–20 years of exposure ## Footnote Usually without associated impairment of lung function.
247
What are the complications associated with progressive massive silicosis?
Obstructive and restrictive ventilatory impairment, respiratory failure ## Footnote It can also be associated with autoimmune disorders.
248
What is Coal Workers’ Pneumoconiosis (CWP)?
A disease due to occupational exposure to coal dust ## Footnote It has significant social, economic, and medical implications.
249
What are the radiographic findings in simple CWP?
Simple radiographically identified CWP seen in ~10% of coal miners ## Footnote Not associated with pulmonary impairment.
250
What is Caplan syndrome?
A combination of coal/silica exposure and rheumatoid arthritis ## Footnote It is associated with complicated Coal Workers’ Pneumoconiosis.
251
What is a coal macule?
A focal collection of coal dust in macrophages around respiratory bronchioles ## Footnote It is a fundamental histopathologic finding in CWP.
252
What are the possible physiological defects in CWP?
Obstructive, restrictive, or mixed defects ## Footnote The predominant abnormality depends on the individual’s lung pathology.
253
What is Beryllium Disease?
A disease associated with industrial exposure to beryllium, with a long latency period ## Footnote It can manifest as acute pneumonitis or chronic granulomatous disease.
254
What is the primary classification method for bacteria?
By staining: Gram-positive vs. Gram-negative ## Footnote Gram-positive bacteria stain blue, while gram-negative bacteria stain red.
255
What distinguishes Gram-positive from Gram-negative bacteria?
Gram-positive bacteria have a thick peptidoglycan cell wall ## Footnote This structural difference affects their staining and susceptibility to antibiotics.
256
What are the two main types of bacteria based on oxygen requirement?
Aerobic and anaerobic ## Footnote Aerobes need oxygen for growth, while anaerobes have difficulties growing in its presence.
257
What are the morphological classifications of bacteria?
Spherical (cocci), cylindric (bacilli), spiral (spirochetes) ## Footnote These shapes help in identifying bacterial species.
258
What are two important Gram-positive cocci pathogens?
Staphylococcus aureus and Streptococcus pyogenes ## Footnote They are differentiated by their morphology and biochemical properties.
259
How do staphylococci appear microscopically?
In grapelike clusters ## Footnote This is different from streptococci, which appear in chains.
260
What biochemical property is used to differentiate staphylococci from streptococci?
Staphylococci produce catalase, while streptococci do not ## Footnote This difference is important for laboratory identification.
261
What are the two main criteria that differentiate staphylococci from streptococci?
Microscopic appearance and biochemical properties. ## Footnote Staphylococci appear in grapelike clusters, while streptococci are arranged in chains. Staphylococci produce catalase; streptococci do not.
262
What is the shape and arrangement of Staphylococcus aureus?
Spherical gram-positive cocci arranged in irregular grapelike clusters. ## Footnote Staphylococcus aureus produces catalase, which is important for its virulence.
263
List the three species of Staphylococcus.
* S. aureus * S. epidermidis * S. saprophyticus
264
What distinguishes Staphylococcus aureus from other species?
Coagulase production. ## Footnote Coagulase is an enzyme that causes the clotting of blood.
265
Where is the main site of colonization for Staphylococcus aureus in humans?
The nose. ## Footnote Approximately 30% of people are colonized at any one time.
266
What are the three exotoxins produced by Staphylococcus aureus?
* Enterotoxin * Toxic Shock Syndrome Toxin * Exfoliatin
267
What type of diseases does Staphylococcus aureus cause?
Pyogenic (pus-producing) diseases and diseases caused by toxins. ## Footnote Examples include abscesses, folliculitis, and toxic shock syndrome.
268
What are the important properties of streptococci?
Spherical gram-positive cocci arranged in chains or pairs, and all are catalase negative.
269
What are the groups of streptococci based on antigenic differences?
Groups A–U (Lancefield groups).
270
What is the most important human pathogen among Group A streptococci?
Streptococcus pyogenes.
271
What is the hemolytic pattern of α-hemolytic streptococci?
A green zone around colonies due to incomplete lysis of red blood cells.
272
What does β-hemolytic streptococci produce that causes complete lysis of red blood cells?
Enzymes called hemolysins, specifically streptolysin O and streptolysin S.
273
What are the three types of diseases caused by Streptococcus pyogenes?
* Pyogenic diseases * Toxigenic diseases * Immunologic diseases
274
What is the leading cause of neonatal sepsis and meningitis?
Streptococcus agalactiae (Group B Streptococcus).
275
What is the common cause of community-acquired pneumonia?
Streptococcus pneumoniae.
276
What enhances the ability of S. pneumoniae to colonize the mucosa of the upper respiratory tract?
IgA protease.
277
What are the main risk factors for pneumonia?
* Defects in normal defense mechanisms * Large infectious inoculum * Virulent pathogens
278
What are the most common viral causes of community-acquired pneumonia?
* Coronaviruses (SARS-CoV-2, MERS) * Influenza virus * Respiratory syncytial virus * Adenovirus * Parainfluenza virus
279
What is a common diagnostic test for community-acquired pneumonia?
Sputum Gram stain and culture.
280
What is the typical clinical presentation for community-acquired pneumonia?
* Fever (>38°C) * Leukopenia or leukocytosis * Altered mental status in adults ≥70 years * New onset of purulent sputum * New-onset or worsening cough, dyspnea, or tachypnea
281
What is the difference between typical and atypical pneumonia?
Typical pneumonia is caused by organisms like S. pneumoniae, while atypical pneumonia is caused by organisms such as Mycoplasma, Chlamydia, and Legionella.
282
What is leukopenia?
Leukopenia is defined as a white blood cell count of <4000 WBC/mm3.
283
What is leukocytosis?
Leukocytosis is defined as a white blood cell count of ≥12,000 WBC/mm3.
284
What altered mental status criteria is significant in adults ≥70 years of age?
Altered mental status without an alternative etiology.
285
What are the symptoms indicating new onset of pneumonia?
New onset of purulent sputum, change in sputum character, or increased secretions/suction requirements.
286
What respiratory symptoms indicate pneumonia?
New-onset or worsening cough, dyspnea, or tachypnea.
287
What are rales?
Rales are abnormal lung sounds indicative of fluid in the alveoli.
288
What characterizes typical CAP pneumonia?
The X-Ray corresponds with clinical findings on physical examination.
289
What is lobar pneumonia?
Lobar pneumonia is acute exudative inflammation of the entire lobe with uniform consolidation.
290
Which pathogen is the majority cause of lobar pneumonia?
Streptococcus pneumoniae.
291
What is bronchopneumonia?
Bronchopneumonia is a type of pneumonia that inflames the alveoli with incomplete consolidation.
292
What are the updated recommendations for the pneumococcal vaccine?
Either PCV20 alone or sequential administration of PCV15 and PPSV23.
293
Who should receive the pneumococcal vaccine?
Adults aged 65 years or older and those with comorbidities.
294
What is atypical pneumonia?
Atypical pneumonia is characterized by X-Ray findings not corresponding with clinical examination.
295
What is the transmission method for Mycoplasma pneumoniae?
Transmitted by respiratory droplets.
296
What percentage of pneumonia cases are due to Mycoplasma pneumoniae?
~20% of pneumonia cases.
297
What age group has the highest incidence of Mycoplasma pneumoniae infection?
Older children and young adults (ages 5-20 years).
298
What is Chlamydia pneumoniae known to cause?
Pharyngitis, bronchitis, and atypical pneumonia.
299
What is the significance of C. pneumoniae antibodies in adults?
About 50% of adults in the U.S. have antibodies to C. pneumoniae.
300
How does Legionella enter the respiratory tract?
By aspiration of contaminated water or inhalation of aerosol.
301
What is Legionnaires disease?
An atypical, acute lobar pneumonia with multisystem symptoms.
302
What differentiates community-acquired pneumonia from nosocomial pneumonia?
Different infectious causes, antibiotic susceptibility patterns, and patient health status.
303
What types of pneumonia are included in nosocomial pneumonia?
Hospital-acquired pneumonia (HAP) and ventilator-acquired pneumonia (VAP).
304
What are common risk factors for HAP?
* Instrumentation of the upper airway * Treatment with broad-spectrum antibiotics * Advanced age * Impaired cellular defense mechanisms
305
What are the microbiological differences between CAP and HAP?
HAP microbiology differs from CAP and includes resistant organisms.
306
What is the most common etiology of early HAP?
Enteric gram-negative bacilli (E. coli, K. pneumoniae, etc.).
307
What is a lung abscess?
A necrotizing lung infection characterized by a pus-filled cavitary lesion.
308
What is the most common cause of lung abscess?
Aspiration of oral secretions.
309
What are common symptoms of lung abscess?
* Productive cough * Fever * Weight loss
310
What is the primary treatment for lung abscess?
Combination beta-lactam/beta-lactamase inhibitor or a carbapenem.
311
What is the historical significance of tuberculosis?
One of the oldest diseases known to affect humans.
312
What is the global impact of tuberculosis?
The top cause of infectious death worldwide excluding COVID-19.
313
What family does Mycobacterium tuberculosis belong to?
Family Mycobacteriaceae.
314
What is zoonotic tuberculosis?
M. bovis transmitted by unpasteurized milk.
315
What is the shape and size of M. tuberculosis?
Rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 μm by 3 μm
316
How are M. tuberculosis bacilli classified?
As acid-fast bacilli due to their inability to be decolorized by acid alcohol after Gram-staining
317
What is the primary mode of transmission for M. tuberculosis?
Through droplet nuclei from infectious pulmonary TB, aerosolized by coughing, sneezing, or speaking
318
What size droplets containing M. tuberculosis can remain suspended in the air?
Droplets smaller than 5–10 μm in diameter
319
What is the estimated number of infectious nuclei per cough from an infected individual?
Up to 3000 infectious nuclei
320
List two types of transmission risk factors for M. tuberculosis.
* Exogenous * Endogenous
321
What are exogenous risk factors for M. tuberculosis transmission?
* Crowding in poorly ventilated rooms * Sputum smear–positive cases
322
What are some endogenous risk factors for M. tuberculosis?
* Degree of immune competence * HIV-infected patients * Cancer treatment * Immunosuppressive drugs
323
What is primary TB?
Clinical illness directly following infection, common among children and immunocompromised persons
324
What is miliary tuberculosis?
A severe and disseminated form of TB that is generally not associated with high-level transmissibility
325
What characterizes post-primary TB in adults?
Reactivation or reinfection of TB later in life; more often infectious than primary disease
326
What percentage of infected persons will develop active TB in their lifetime?
Up to 10%
327
What are common clinical symptoms of TB?
* Fatigue * Nocturnal sweating * Increased temperature * Weight loss * Cough with expectoration * Hemoptysis * Pleural pain (rarely) * Dyspnea (rarely)
328
What is the purpose of the Tuberculin Test?
To detect TB infection through intradermal injection of tuberculin (PPD-RT)
329
What indicates active infection on a Tuberculin Test?
More than 15 mm induration
330
What is atelectasis?
A medical condition characterized by the collapse or incomplete expansion of a part or all of the lung
331
Name the major types of atelectasis.
* Resorption atelectasis * Compression atelectasis * Contraction atelectasis
332
What causes resorption atelectasis?
Blocking of an airway leading to a portion of the lung, preventing air from reaching the alveoli
333
List some major causes of resorption atelectasis.
* Aspiration of a foreign body * Tumor or other growth * Mucous plug
334
What is compression atelectasis?
Occurs when there is external pressure on the lung, preventing it from expanding fully
335
What is the normal function of the pleura?
* Protection * Lubrication * Support
336
What are the two layers of the pleura?
* Visceral Pleura * Parietal Pleura
337
What is pleural effusion?
An abnormal collection of fluid in the pleural space
338
Differentiate between transudative and exudative pleural effusions.
* Transudate: Protein- and cell-poor fluid * Exudate: Rich in protein and often cells
339
What are some causes of transudative pleural effusions?
* Congestive heart failure * Cirrhosis * Nephrotic syndrome * Constrictive pericarditis
340
What is parapneumonic effusion?
Accumulation of fluid in the pleural space as a complication of pneumonia
341
What are the three main types of infectious pleural effusions?
* Uncomplicated * Complicated * Empyema
342
What symptoms are caused by pleural effusion?
* Dyspnea * Chest pain
343
True or False: Late treatment of serious infectious effusions can threaten a patient’s life.
True
344
Fill in the blank: The ________ is a specialized type of epithelial tissue that lines body cavities.
[mesothelium]
345
What does the mesothelium consist of?
A single layer of flattened to cuboidal cells known as mesothelial cells
346
What is the normal intrapleural pressure?
Around -10 cm water at the lung bases
347
What is the mnemonic used in medicine regarding parapneumonic effusions?
The phrase emphasizes the urgency of diagnosing and treating parapneumonic effusions promptly before sunset. ## Footnote Timely intervention is crucial to prevent complications.
348
What is the typical treatment for parapneumonic effusions that progress to empyema?
Draining the fluid and sometimes using clot-busting drugs and DNA-ase enzymes. ## Footnote These treatments improve drainage and reduce complications.
349
What are transudates and exudates in the context of pleural effusions?
Transudates are typically bilateral, while exudates can be uni- or bilateral. ## Footnote Exudates require further investigation to rule out cancer.
350
What is the initial study for diagnosing pleural effusions?
Chest radiograph is a decent initial study, both upright and decubitus. ## Footnote Ultrasound and CT are more effective in detecting effusions.
351
What are the two meanings of 'influenza'?
* Syndrome: systemic symptoms of fever, malaise, myalgia, and respiratory symptoms * Microbe: influenza virus that infects the respiratory tract. ## Footnote The systemic symptoms typically accompany the syndrome.
352
What are the two most clinically important types of influenza viruses?
Influenza A and Influenza B. ## Footnote Both are orthomyxoviruses and negative-sense single-stranded RNA viruses.
353
What are the major proteins relevant to influenza?
* Neuraminidase * Viral hemagglutinin * RNA-dependent RNA polymerase proteins. ## Footnote These proteins play crucial roles in viral entry and replication.
354
What is antigenic shift in influenza viruses?
A sudden and major change in the antigenic properties due to the exchange of genetic material between different influenza viruses. ## Footnote This can lead to the emergence of new subtypes capable of causing pandemics.
355
What is antigenic drift in influenza viruses?
Gradual and incremental changes in the antigenic properties due to mutations in the viral genome. ## Footnote This leads to seasonal influenza epidemics as the virus evolves to evade immunity.
356
What is the life cycle of Influenza A or B characterized by?
Binding due to hemagglutinin and budding due to neuraminidase. ## Footnote These processes are essential for viral entry and spread.
357
What are the common clinical features of influenza?
* Cough * Sore throat * Rhinorrhea * Systemic symptoms like fatigue and myalgias. ## Footnote Symptoms typically develop over hours with a brief incubation period.
358
What are potential complications of influenza?
* Bacterial superinfection * Severe pneumonia * Myocarditis * Guillain-Barre syndrome. ## Footnote Complications can lead to significant morbidity and mortality.
359
How is influenza diagnosed?
Diagnosis is usually clinical, confirmed by NAAT tests (nasopharyngeal swab). ## Footnote Serology is not typically used for diagnosis.
360
What factors influence the severity of influenza epidemics?
* Antibody effectiveness * Ability to transmit from human to human * Other virulence factors. ## Footnote These factors determine the clinical impact of influenza outbreaks.
361
What is the role of the immune response in influenza infection?
Activates innate and adaptive immune mechanisms to target and eliminate virus-infected cells. ## Footnote Excessive immune response can lead to severe symptoms and complications.
362
What is the typical treatment for severe influenza?
Neuraminidase inhibitors are used if given within 48 hours of onset. ## Footnote Vaccinations have a modest effect on reducing symptoms and hospitalizations.
363
What is the general microbiology of COVID-19?
Caused by SARS-CoV-2, a betacoronavirus, with a single linear RNA segment of nearly 30,000 nucleotides. ## Footnote It encodes four structural proteins: S, E, M, and N.
364
What is the primary mode of transmission for COVID-19?
Droplet transmission, including larger droplets and smaller aerosols. ## Footnote Contact with contaminated surfaces can also lead to infection.
365
What are the systemic symptoms associated with influenza?
* Fatigue * Myalgias * Shaking chills * Headache. ## Footnote These symptoms often accompany respiratory symptoms.
366
What appearance does SARS-CoV-2 give?
Crown of thorns or a solar corona
367
Name the surface proteins associated with SARS-CoV-2.
* Hemagglutinin-acetylesterase glycoprotein * Membrane glycoprotein * Small envelope glycoprotein
368
What are the modes of transmission for SARS-CoV-2?
* Droplet transmission * Contact from colonized surfaces
369
What types of droplets are involved in droplet transmission?
* Larger droplets that fall to the ground quickly * Smaller droplets (aerosols) that remain airborne longer
370
What initial cells are targeted for viral colonization by SARS-CoV-2?
Nasopharyngeal/oropharyngeal cells
371
Which cells can be invaded by SARS-CoV-2 after initial colonization?
* Bronchial epithelium * Alveolar epithelial cells * Vascular endothelial cells * Alveolar macrophages
372
What types of vascular endothelial cells can SARS-CoV-2 invade?
* Heart endothelial cells * Kidney endothelial cells
373
Which other cell types express ACE-2?
* Enterocytes * Cholangiocytes * Myocardial cells * Kidney cells * Bladder urothelial cells
374
Why is COVID-19 so transmissible?
It replicates in the upper airways
375
In which stages of infection does SARS-CoV-2 replicate?
* Symptomatic stages * Pre-symptomatic stages
376
How does the transmissibility of SARS-CoV-2 compare to SARS-CoV-1 and MERS?
SARS-CoV-2 is more transmissible; SARS-CoV-1 and MERS have higher death rates
377
What is the R0 rate for SARS-CoV-2?
Between 5 and 6
378
What is the R0 rate for influenza?
Between 1 and 2
379
Does enteric replication impact the transmissibility of SARS-CoV-2?
No one is sure; likely not
380
What effect does enteric replication have during symptomatic phases?
Exacerbates inflammation
381
What is the function of the spike protein's receptor binding domain?
Binds to the ACE2 enzyme on cells
382
What allows for viral entry into host cells?
Cleavage of the spike protein by TMPRSS2
383
What forms after the cleavage of the spike protein?
Endosome
384
What happens after the viral genome is released in the cytoplasm?
Translation in a polyprotein followed by cleavage
385
What are some functions of the proteins produced after viral genome translation?
* Continued replication (RNA-dependent RNA polymerase) * Viral particle assembly * Inhibition of type I interferons
386
How does SARS-CoV-2's mutation rate compare to influenza?
Relatively low rate of mutation due to exonuclease activity
387
What is a cytokine storm?
A hyper-inflammatory response triggered by highly virulent viruses such as H5N1, H1N1, and COVID-19 ## Footnote It leads to acute respiratory distress syndrome (ARDS) in infected patients.
388
Which cytokines are primarily involved in a cytokine storm?
Interferon-γ, TNF-α, IL-1, IL-6 ## Footnote These proinflammatory cytokines stimulate multiple organ systems.
389
What is the role of TMPRSS2 in early lung inflammation?
Promotes viral uptake by cleaving ACE2 and activating the SARS-CoV-2 S-protein ## Footnote This process facilitates the infection of bronchial epithelial cells and alveolar pneumocytes.
390
What occurs during late lung inflammation in COVID-19?
Release of kinins activates kinin receptors, leading to vascular smooth muscle relaxation and increased permeability ## Footnote This is controlled by the ACE2 receptor.
391
What are the symptoms associated with mild to moderate COVID-19?
Fever, cough, shortness of breath, fatigue, muscle aches, headache, loss of taste or smell, sore throat, congestion, nausea, diarrhea ## Footnote Approximately 80% of symptomatic individuals experience these symptoms.
392
What percentage of COVID-19 patients remain asymptomatic?
Approximately 30% ## Footnote This indicates a significant portion of individuals do not exhibit symptoms despite being infected.
393
What are the severe symptoms of COVID-19?
Dyspnea, cyanosis, chest pain, confusion, inability to wake ## Footnote Severe symptoms can lead to complications like ARDS and multi-organ failure.
394
What is the estimated mortality rate of COVID-19?
Just over 2% ## Footnote This estimate is based on the global death toll, which is approximately 7 million.
395
What major factors increase the risk of severe COVID-19 complications?
* Advanced age * Male sex * Racial and ethnic minorities * Chronic conditions (cardiovascular disease, diabetes, etc.) * Immunocompromised status ## Footnote Over 80% of deaths occur in individuals over age 65.
396
What do the kidneys do?
Produce urine and convey it via ureters to the urinary bladder ## Footnote They also interact with suprarenal glands, which are part of the endocrine system.
397
Where do the renal arteries arise?
At the level of the IV disc between the L1 and L2 vertebrae ## Footnote The right renal artery passes posterior to the IVC.
398
What structures enter and exit the renal sinus through the renal hilum?
Vessels, nerves, and structures that drain urine from the kidney ## Footnote The hilum is the entrance to the renal sinus.
399
What is the role of the renal nerve plexus?
Supplies sympathetic and parasympathetic fibers to the kidneys ## Footnote It is involved in the autonomic regulation of kidney function.
400
What are umbrella cells?
Specialized epithelial cells in the urinary bladder that maintain wall integrity ## Footnote They are resistant to urine and facilitate bladder expansion.
401
What is the function of the internal urethral sphincter?
Controls involuntary urine flow from the bladder to the urethra ## Footnote In males, it also prevents the flow of semen into the bladder during ejaculation.
402
What is micturition?
The process of bladder emptying, involving complex neural circuitry ## Footnote It allows for voluntary control based on perceived bladder fullness.
403
Fill in the blank: The _______ is released from tonic inhibitory control to initiate the voiding process.
pontine micturition center
404
What are the two types of nerves that supply the bladder?
* Sympathetic fibers * Parasympathetic fibers ## Footnote They regulate bladder function during filling and voiding phases.
405
What is a unique feature of COVID-19 related hypoxemia?
Significant hypoxemia (< 90% oxygen saturation) with limited dyspnea ## Footnote This unusual symptom warrants further investigation into its mechanisms.
406
What are umbrella cells?
Superficial specialized epithelial cells found in the lining of the urinary tract, particularly in the urinary bladder.
407
What is the role of umbrella cells in the bladder?
Maintain the integrity and impermeability of the bladder wall.
408
How do umbrella cells adapt their apical membrane?
They have numerous densely packed, rigid, hexagonally arranged Uroplakin plaques.
409
What is the function of tight junctions in umbrella cells?
Create a barrier that regulates the movement of ions, water, and solutes across the epithelium.
410
What allows umbrella cells to accommodate changes in bladder volume?
The apical surface can expand and contract significantly.
411
What provides structural support to umbrella cells?
Cytokeratin filaments and actin bundles.
412
What specialized transport mechanisms do umbrella cells possess?
They express aquaporin water channels to facilitate the rapid reabsorption of water.
413
What is uroplakin turnover?
The continuous synthesis and turnover of uroplakins to maintain the apical membrane integrity.
414
What does the term 'vesicoureteric' refer to?
The junction between the urinary bladder and the ureter.
415
What is vesicoureteral reflux (VUR)?
A condition where urine flows backward from the bladder into one or both ureters.
416
How is vesicoureteral reflux classified?
Into different grades from I (mildest) to V (most severe).
417
What are the typical symptoms of uncomplicated cystitis?
Dysuria, urinary frequency, urgency.
418
What distinguishes complicated cystitis from uncomplicated cystitis?
Unilateral back or flank pain and fever suggest involvement of the upper urinary tract.
419
What is pyelonephritis?
A kidney infection that can present with fever, flank pain, and other symptoms.
420
What is the main feature distinguishing cystitis from pyelonephritis?
Fever.
421
What is urosepsis?
A systemic inflammatory response due to bacteria from the urinary tract entering the bloodstream.
422
What is the predominant microorganism in normal vaginal microbiota?
Lactobacillus species.
423
What role do Lactobacillus species play in vaginal health?
They create an acidic environment and produce antimicrobials to inhibit harmful bacteria.
424
What increases the risk factors for urinary tract infections?
* Obstruction * Short urethra length * Bladder catheterization.
425
What is the most frequent pathogen causing urinary tract infections?
E. coli.
426
What are P fimbriae?
Hair-like protein structures that help E. coli bind to specific receptors on uroepithelial cells.
427
True or False: Asymptomatic bacteriuria always requires treatment.
False.
428
Fill in the blank: The typical symptoms of _______ cystitis include dysuria, urinary frequency, and urgency.
uncomplicated
429
What amino acids are required for optimal growth of Proteus?
Guanine, arginine, and glutamine ## Footnote These amino acids are essential for the bacterial synthesis and growth of Proteus
430
What role do ureases produced by Proteus mirabilis play in pyelonephritis?
They generate ammonium, raising urine pH above 7 ## Footnote This alkaline urine enhances bacterial growth and increases the likelihood of renal stones.
431
How does alkaline urine affect bacterial growth?
Enhances bacterial growth and increases likelihood of renal stones ## Footnote Alkaline conditions promote the survival and proliferation of certain bacteria.
432
What immunological factor does Proteus produce?
Immunoglobulin A (IgA) protease ## Footnote This factor helps the bacteria evade immune responses.
433
What is the function of flagella in Proteus?
Allows bacteria to migrate up the urethra and adhere to epithelial cells ## Footnote The expression of flagella is regulated by operons responding to external conditions.
434
How do endotoxins contribute to pyelonephritis?
Decrease ureteral peristalsis, slowing urine flow ## Footnote This enhances the ability of gram-negative bacteria to ascend into the kidneys.
435
What is a key characteristic of Klebsiella bacteria in healthcare settings?
Adhere to and colonize mucosal surfaces of the bladder or kidney tissues ## Footnote This adherence is facilitated by fimbriae and adhesins.
436
What mechanisms do Klebsiella use to evade the immune system?
Invade bladder epithelial cells ## Footnote This allows them to evade detection and persist within the urinary tract.
437
What is the significance of biofilm formation in Klebsiella infections?
Provides protection against antibiotics and host immune responses ## Footnote Biofilms make eradication of infections more challenging.
438
List some virulence factors produced by Klebsiella.
* Capsule polysaccharides * Lipopolysaccharides (LPS) * Siderophores * Toxins ## Footnote These factors aid in evading host defenses and causing tissue damage.
439
What is a common association with enterococcal UTIs?
Indwelling catheterization, instrumentation, or anatomic abnormalities ## Footnote These factors increase the risk of enterococcal infections.
440
What are the clinical manifestations of interstitial cystitis?
Discomfort and/or pain perceived to be related to the bladder, urinary frequency, and urgency ## Footnote This severely impacts quality of life and social interactions.
441
What are some proposed etiologies of interstitial cystitis?
* Infection and the urinary microbiota * Autoimmunity * Inflammation * Urothelial dysfunction ## Footnote These factors may contribute to the pathophysiology of the condition.
442
What is the primary function of the urothelium?
Provide a robust barrier layer ## Footnote This is achieved through glycosaminoglycans (GAGs) and tight junctions among urothelial cells.
443
What is the clinical relevance of Hunner lesions in interstitial cystitis?
Discrete inflammatory lesions associated with a well-characterized inflammatory profile ## Footnote They are identifiable via cystoscopy and are indicative of bladder inflammation.
444
What is the economic impact of interstitial cystitis?
Similar to fibromyalgia, low back pain, rheumatoid arthritis, and peripheral neuropathy ## Footnote Associated disability can significantly affect quality of life.
445
What is the most common site of urinary tract tumors?
Urinary bladder ## Footnote Bladder cancer is the most prevalent urologic malignancy.
446
What are the most common types of bladder tumors?
* Urothelial malignant neoplasms * Squamous cell cancers * Adenocarcinomas * Neuroendocrine malignancies * Sarcomas ## Footnote Urothelial tumors account for 90% of bladder cancers.
447
What factors increase the risk of bladder cancer?
* Cigarette smoking * Industrial exposure to azo dyes * Infection with S. haematobium * Certain drugs and radiation therapy ## Footnote These factors contribute to a significant percentage of new bladder cancer cases.
448
What is a urothelial papilloma?
Benign tumors usually discovered incidentally during cystoscopy ## Footnote They represent less than 1% of bladder tumors.
449
What characterizes urothelial carcinoma in situ?
Full-thickness lesions confined to the bladder mucosa ## Footnote Associated with a risk of subsequent invasive carcinoma.
450
What is the clinical presentation of urothelial carcinoma?
Sudden hematuria and less often dysuria ## Footnote At presentation, 85% of tumors are confined to the bladder.
451
What diagnostic tools are used for bladder cancer?
* Urinalysis * Imaging studies (Ultrasound, CT, MRI) ## Footnote These are crucial for evaluating bladder masses and staging.
452
What percentage of tumors are confined to the urinary bladder?
85% ## Footnote 15% show regional or distant metastases.
453
What system is used for staging bladder cancers?
Tumor node metastasis (TNM) system
454
What are the common sites of metastases for bladder cancer?
* Regional lymph nodes * Periaortic lymph nodes * Liver * Lung * Bone
455
What does urinalysis commonly detect in bladder cancer?
* Hematuria * Pyuria
456
What imaging studies are useful for bladder cancer evaluation?
* Ultrasound * CT * MRI
457
What is the sensitivity of urine cytology for detecting higher grade and stage cancers?
80–90%
458
What procedures are used for diagnosis and staging of bladder cancer?
* Cystourethroscopy * Tumor biopsy * Random bladder biopsies * Transurethral prostate biopsies
459
What is TURBT?
Transurethral resection of bladder tumor
460
What are the three stages of the nephric system?
* Pronephros * Mesonephros * Metanephros
461
What is the main function of the pronephros?
Temporary filtration system
462
When does the pronephros disappear?
By the 4th week
463
What structures develop from the mesonephros?
* Bowman's capsule * Glomerulus
464
What is the significance of the metanephros?
Primitive proper kidney
465
At what level does the metanephros arise?
Opposite the 28th somite (L4)
466
What are the anatomical features of the kidneys?
* Bean-shaped organs * Located under the rib cage * Close to the posterior abdominal wall
467
What is the flow path of urine in the kidneys?
* Pyramids * Papilla * Minor calyx * Major calyx * Renal pelvis * Ureter
468
What is the functional unit of the kidney?
Nephron
469
What are the two arterioles associated with the renal corpuscle?
* Afferent arteriole * Efferent arteriole
470
What is the function of glomerular mesangial cells?
* Remove trapped material * Provide physical support * Release cytokines * Maintain filtration rate
471
What is the main role of podocytes?
Support structures with a sieving role in filtration
472
What does the proximal convoluted tubule primarily reabsorb?
* Water * Glucose * Amino acids * Ions
473
What is the purpose of the loop of Henle?
Establish concentration gradient in the medulla
474
What specialized cells mark the end of the thick ascending limb?
Macula densa
475
What type of cells are found in the distal convoluted tubule?
* Principal cells * Intercalated cells
476
What is the function of the collecting duct?
Water reabsorption and ion balance
477
What are the three constriction sites of the ureters?
* Renal pelvis * Pelvic brim * Entrance to the bladder
478
Where does the ureter enter the bladder?
Posterolaterally via the trigone
479
What is the detrusor muscle responsible for?
Contraction causes urination
480
What type of muscle is the internal urethral sphincter?
Smooth muscle
481
What nerve innervates the external urethral sphincter?
Pudendal nerve (S2–S4)
482
What are the vascular supplies to the urinary bladder?
* Superior vesical arteries * Inferior vesical arteries * Vaginal arteries (in females)
483
What is the micturition reflex?
Process initiated by bladder distension leading to urination
484
What are the three parts of the male urethra?
* Prostatic * Membranous * Penile
485
What is the histological feature of the mucosa of the calyx?
Dense connective tissue and adipose tissue
486
What do interlobular arteries give off in the cortex?
Afferent arterioles ## Footnote Afferent arterioles bring blood to the glomerular capillaries.
487
What is the composition of the parietal layer of a glomerular capsule?
Simple squamous epithelium supported by a basal lamina.
488
What type of epithelium is found at the tubular pole of the glomerular capsule?
Simple cuboidal epithelium.
489
What are podocytes?
Unusual stellate epithelial cells in the visceral layer of the glomerular capsule.
490
What do primary processes of podocytes do?
Extend and curve around a length of glomerular capillary.
491
What are pedicels?
Parallel, interdigitating secondary processes from podocytes.
492
Where are filtration slit pores located?
Between the pedicels.
493
What bridges the slit pores in the glomerular filtration barrier?
Zipper-like slit diaphragms.
494
What is the role of the glomerular basement membrane?
Separates blood from the capsular space.
495
What type of epithelium lines the proximal convoluted tubule (PCT)?
Simple cuboidal epithelium.
496
What feature of proximal tubule cells facilitates reabsorption?
Long microvilli forming a brush border.
497
What characterizes the thin descending and ascending limbs of the loop of Henle?
Composed of simple squamous epithelia.
498
What type of cells are found in the distal convoluted tubule (DCT)?
Simple cuboidal cells.
499
How do the cells of DCT differ from those of PCT?
DCT cells are smaller and lack a brush border.
500
What is the macula densa?
Columnar and closely packed cells at the vascular pole.
501
What is the function of juxtaglomerular (JG) cells?
Secrete renin.
502
What type of cells are principal cells in the collecting ducts?
Pale-staining cells with few organelles.
503
What is the primary function of principal cells?
Ion transport.
504
What type of epithelium lines the ureters?
Urothelium (transitional epithelium).
505
What are the three layers of urothelium?
* Basal cells * Intermediate region * Umbrella cells.
506
What type of epithelium lines the prostatic urethra in males?
Urothelium.
507
What epithelium lines the membranous urethra in males?
Stratified columnar and pseudostratified columnar epithelium.
508
What type of epithelium does the female urethra transition to?
Nonkeratinized stratified squamous epithelium.
509
What is the functional unit of the kidney?
Nephron.
510
What are the two parts of the nephron?
* Glomerulus * Bowman’s capsule.
511
What are the two types of nephrons?
* Cortical nephrons * Juxtamedullary nephrons.
512
What is the primary function of the glomerulus and Bowman’s capsule?
Site where blood is filtered through a specialized membrane.
513
What is the primary function of the proximal convoluted tubule?
Reabsorb the majority of solutes and water.
514
What do loops of Henle contribute to?
Concentration of urine.
515
What is renal clearance?
Volume of plasma from which a substance is completely removed by the kidneys per unit of time.
516
What factors determine filtration in the kidneys?
Starling forces and permeability of the filtration membrane.
517
What are the three ways the kidneys handle substances?
* Filtration * Secretion * Reabsorption.
518
What is glomerular filtrate?
Initial filtrate containing substances that will become urine.
519
What is the renal blood flow in terms of cardiac output?
1 L of blood/min (about 20% of the cardiac output) ## Footnote Renal blood flow is much higher than the metabolic demand of the kidney.
520
What is the renal plasma flow (RPF)?
600 ml/min available for filtration ## Footnote This is the volume of plasma that is filtered at the glomerulus.
521
What is the glomerular filtration rate (GFR) for most people with good renal function?
120 ml/min ## Footnote This is approximately 20% of the renal plasma flow.
522
What does eGFR stand for?
Estimated glomerular filtration rate ## Footnote It estimates how well kidneys filter waste products from the blood.
523
What is the normal range for eGFR?
Above 90 mL/min/1.73m² ## Footnote Values below this indicate decreased kidney function.
524
What are the components of the filtration barrier in the glomerulus?
* Fenestrations in glomerular capillaries * Basement membrane * Filtration slits between podocytes ## Footnote These components are crucial for the filtration process.
525
What types of molecules can pass through the glomerular filtration barrier?
* Water * Ions * Glucose * Amino acids * Waste products ## Footnote Larger molecules like proteins and blood cells are retained.
526
What is the role of charged ions in the glomerular filtration process?
They contribute to the selective permeability of the filtration barrier ## Footnote The barrier is permeable to ions but relatively impermeable to larger charged molecules.
527
What is the equation for net filtration pressure (NFP) across the glomerulus?
NFP = Kf · (PGC – PBC – πGC) ## Footnote This equation takes into account the pressures involved in filtration.
528
How does constricting the afferent arteriole affect GFR?
Decreases GFR ## Footnote It impacts the delivery of blood to the capillary.
529
What is autoregulation in the context of GFR?
The glomerulus maintains a relatively constant GFR despite changes in systemic blood pressure ## Footnote It involves intrinsic mechanisms like myogenic response and tubuloglomerular feedback.
530
What happens during tubuloglomerular feedback when too much solute is delivered to the macula densa?
Less renin is secreted, leading to a drop in GFR ## Footnote ATP or adenosine released by the macula densa plays a role in this feedback mechanism.
531
What is the effect of angiotensin II on GFR?
Increases GFR by constricting the efferent arteriole more than the afferent arteriole ## Footnote This results in increased overall renal resistance.
532
What is azotemia?
Low filtration at the glomerulus, leading to a buildup of waste in the blood ## Footnote It can be categorized into pre-renal, renal, and post-renal azotemia.
533
What substance can be used to measure GFR as it is only filtered and not secreted or reabsorbed?
Inulin ## Footnote It must reach a steady state in the bloodstream for accurate measurement.
534
What is the significance of creatinine in measuring GFR?
It is filtered and has a small amount secreted, used to estimate GFR ## Footnote Creatinine clearance requires blood and urine samples.
535
What is the major body fluid compartment distribution?
* 60% or greater of the body is water * 2/3 intracellular (27 L) * 1/3 extracellular * Blood plasma is about 3 L (20% of ECF) ## Footnote Understanding fluid compartments is important for kidney function.
536
What is hyponatremia?
A condition characterized by low sodium levels in the blood.
537
If a person has hyponatremia, have they reduced their secretion of sodium into the urine?
No, the kidney may be the problem.
538
What is the total body water percentage?
60% or greater.
539
How is body water distributed between intracellular and extracellular compartments?
2/3 intracellular (27 L) and 1/3 extracellular.
540
What is the volume of blood plasma?
About 3 L (20% of ECF).
541
What is the volume of interstitial fluid?
About 10-11 L (80% of ECF).
542
What happens when fluid or salt is added to the bloodstream?
It spreads freely between the ECF spaces but may not easily spread to the intracellular space.
543
What are the major cellular transport mechanisms involved in nephron function?
* Passive Diffusion * Facilitated Diffusion * Active Transport * Secondary Active Transport (Symport and Antiport) * Endocytosis and Exocytosis
544
Define passive diffusion.
Movement of molecules across the tubular epithelium down their concentration gradient without energy.
545
What is facilitated diffusion?
Movement of molecules across the cell membrane through specific carrier proteins or channels.
546
What is active transport?
Movement of molecules against their concentration gradient, requiring energy (ATP).
547
What is the role of the Na+/K+-ATPase pump?
It actively transports sodium ions out of tubular epithelial cells and potassium ions into the cell.
548
What does secondary active transport involve?
Coupled movement of two or more molecules across the cell membrane.
549
What is the difference between symport and antiport?
* Symport: molecules move in the same direction * Antiport: molecules move in opposite directions.
550
What is endocytosis?
Process by which cells engulf extracellular substances by forming vesicles.
551
What is exocytosis?
Process where vesicles containing substances fuse with the cell membrane, releasing contents.
552
What are the approximate concentrations of Na+, K+, Cl-, and HCO3- in ICF and ECF?
Know approximate values for these ions.
553
What is insensible water loss?
Water loss from the skin that we are not aware of.
554
What are the two major routes of renal tubule transport?
* Transcellular route * Paracellular route
555
What fraction of body weight is water?
About 60%.
556
What is the osmotic content of extracellular fluid primarily accounted for by?
* Sodium * Chloride
557
What percentage of filtered sodium is reabsorbed in the proximal tubule?
About 65%.
558
What is the primary active transport mechanism for sodium reabsorption?
Na-K-ATPase pumps in the basolateral membrane.
559
What is the final urine sodium content?
Less than 1% of the total filtered sodium.
560
What is the role of chloride reabsorption in the kidneys?
Chloride is reabsorbed similarly to sodium, maintaining electroneutrality.
561
What is the primary mechanism for water reabsorption in the proximal tubule?
Water follows sodium reabsorption.
562
What is the function of aquaporins in renal cells?
Facilitate water reabsorption across cell membranes.
563
What occurs in the descending limb of Henle's loop?
Water is reabsorbed.
564
What occurs in the ascending limb of Henle's loop?
Sodium is reabsorbed.
565
What is the significance of the Na+/K+ ATPase in the nephron?
Establishes electrochemical gradients for reabsorption.
566
What substances are primarily reabsorbed by the proximal convoluted tubule (PCT)?
* Sodium * Glucose * Amino acids * Bicarbonate * Water
567
What is sodium-glucose co-transport?
Mechanism where sodium ions are transported into PCT cells along with glucose.
568
What happens to glucose after it enters the PCT cell?
Exits via facilitated diffusion into the bloodstream.
569
What is the mechanism by which glucose is reabsorbed from the filtrate into PCT cells?
Secondary active transport via sodium-glucose co-transport
570
Which transporters are involved in the reabsorption of glucose in the PCT?
Sodium-glucose co-transporter 2 (SGLT2) and sodium-glucose co-transporter 1 (SGLT1)
571
How does glucose exit PCT cells after being reabsorbed?
Facilitated diffusion through glucose transporter proteins (GLUT2 or GLUT1)
572
What type of transport mechanisms are used for amino acid reabsorption in the PCT?
Secondary active transport mechanisms involving sodium co-transporters
573
How are phosphate ions reabsorbed in the PCT?
Via sodium-dependent phosphate co-transporters
574
What role do Na+/K+-ATPase pumps play in phosphate reabsorption?
They generate a sodium gradient that allows phosphate to move against its concentration gradient
575
How are bicarbonate ions reabsorbed in the PCT?
Through the exchange of bicarbonate ions for chloride ions via the sodium-bicarbonate co-transporter (NBC)
576
What is the primary driving force for water reabsorption in the PCT?
Osmosis, driven by the reabsorption of solutes such as sodium and glucose
577
What happens to sodium ions after they are reabsorbed into PCT cells?
They are pumped out into the interstitial fluid and bloodstream by Na+/K+-ATPase pumps
578
How are potassium and chloride ions reabsorbed in the PCT?
Paracellularly along with water through passive diffusion
579
What is the first method for sodium reabsorption in the PCT?
Na+/K+ ATPase pumps sodium across the basolateral membrane and sodium enters the cell via transporters or channels across the apical membrane
580
What is the second method for sodium reabsorption in the PCT?
HCO3- combines with H+, is converted to CO2, which diffuses into the PCT cell
581
What is the role of carbonic anhydrase in sodium reabsorption?
It converts carbon dioxide to carbonic acid
582
What is the relationship between the two mechanisms of sodium reabsorption in the PCT?
They work hand-in-hand, with the sodium gradient driving water and electrolyte reabsorption
583
What is the main function of the early part of the PCT?
Reabsorption of solutes, nutrients, and bicarbonate
584
What does the latter part of the PCT primarily reabsorb?
Sodium, chloride, and water
585
How do sodium and chloride concentrations change along the length of the PCT?
They stay the same since water is reabsorbed at a nearly equimolar rate
586
Where are most organic solutes transported?
Only in the PCT
587
What happens if glucose and amino acids are not reabsorbed in the PCT?
They will not be reabsorbed further down the nephron and will be lost in the urine
588
What drives the reabsorption of most organic solutes?
Sodium gradient or negative membrane potential
589
What is the capacity of many transporters in the PCT?
Up to 100 different solute species
590
How are proteins like albumin and peptide/protein hormones degraded in the PCT?
Through a process of continuous endocytosis (pinocytosis)
591
How is glucose taken up across the apical membrane in the PCT?
By sodium-glucose symporters (SGLT family)
592
How does glucose leave the PCT across the basolateral membrane?
Via glucose uniporters (GLUT family)
593
What is the stoichiometry of sodium-glucose transport in most of the proximal tubule?
One-for-one
594
Which SGLT isoform is responsible for most glucose reabsorption?
SGLT-2 isoform
595
What is the stoichiometry of sodium-glucose transport in the late proximal tubule?
Two-for-one (SGLT-1 isoform)
596
When is glucose reabsorption saturated?
In the setting of significant (pathologic) hyperglycemia
597
What are organic cation and organic anion transporters known as?
OCTs and OATs, respectively
598
What do OCTs use to move cations from the bloodstream into the PCT cell?
The inside-negative membrane potential
599
What mechanism do OATs use to transport substances?
Countertransport
600
What role do principal cells play in the kidney?
Regulating sodium and water transport under the influence of aldosterone
601
What channels allow sodium ions to move into principal cells?
Epithelial sodium channels (ENaC)
602
How does aldosterone enhance sodium reabsorption?
By increasing the number and activity of ENaC channels
603
What creates an osmotic gradient that promotes water reabsorption?
Sodium reabsorption by principal cells
604
What channels allow water to move passively into principal cells?
Aquaporin-2 (AQP2) water channels
605
How does aldosterone indirectly enhance water reabsorption?
By promoting sodium reabsorption
606
What is the role of principal cells in potassium secretion?
They secrete potassium ions into the tubular lumen
607
How does aldosterone affect sodium-potassium pumps?
It stimulates their activity on the basolateral membrane
608
What is the major site of secretion of many general wastes/substances?
The PCT
609
What mechanisms are involved in the formation of dilute and concentrated urine?
Countercurrent exchange and multiplication mechanisms
610
What are the distinct histological characteristics of the loop of Henle?
Descending limb is permeable to water; ascending limb is impermeable to water but actively transports ions
611
What is the effect of the countercurrent multiplier system?
It amplifies the concentration gradient in the medulla
612
What does ADH do in relation to water reabsorption?
Increases permeability of collecting ducts to water
613
What do urea transporters contribute to in the medullary osmotic gradient?
Facilitating urea reabsorption in the collecting ducts
614
What is the role of the NKCC channel in the thick ascending limb?
Actively transports sodium, potassium, and chloride ions out of the tubule
615
What is a key action of angiotensin II?
Stimulates sodium tubular reabsorption
616
What stimulates the secretion of renin by JG cells?
Sympathetic input, pressure in the afferent arteriole, macula densa release
617
What does angiotensin II do in the vasculature?
Causes vasoconstriction
618
Where is angiotensinogen synthesized?
In the liver
619
What regulates the level of circulating renin?
Dietary sodium intake
620
What effect does low tubular sodium have on renin secretion?
Stimulates the release of renin
621
What happens to renin secretion when there is high vascular pressure?
It is suppressed
622
What is the primary function of the renin-angiotensin-aldosterone system (RAAS)?
Regulating renal sodium excretion
623
What does angiotensin II stimulate in the CNS?
Salt appetite, thirst, and sympathetic drive
624
What channels are inserted into the apical membrane of collecting duct cells by ADH?
Aquaporin-2 channels
625
What structure of the nephron maximizes the countercurrent exchange and multiplier mechanisms?
Hairpin loop structure
626
What is the role of vasa rectae in the medullary osmotic gradient?
Exchanges ions and water with the surrounding interstitium
627
What is the effect of constricting both cortical and medullary vessels in the kidney?
Reduces total renal blood flow and decreases GFR, thus decreasing the filtered load of sodium.
628
What are ACE inhibitors used for?
They reduce the production of AT2.
629
What does aldosterone stimulate in the nephron?
Sodium reabsorption in both the proximal tubule and distal nephron.
630
Which sodium transporters are stimulated by aldosterone in the proximal tubule?
* NHE3 sodium/hydrogen antiporter * Na-K-ATPase
631
What is the role of NCC in the distal tubule?
It is a sodium/chloride symporter that imports sodium.
632
What is a major stimulator of sodium reabsorption in the distal nephron?
Aldosterone.
633
What happens to aldosterone in the presence of elevated AT2 levels?
It promotes the activity of luminal NCC sodium/chloride symporters in the distal tubule.
634
True or False: Aldosterone is effective at stimulating NCC activity without AT2.
False.
635
What are the cellular targets of aldosterone?
Cells in the distal tubule and beyond.
636
How does aldosterone act on tubular cells?
It combines with mineralocorticoid receptors in the cytoplasm.
637
What is the consequence of aldosterone binding to its receptor?
It promotes gene expression of specific proteins.
638
What is the role of aldosterone in other epithelial tissues?
Stimulates sodium transport in sweat and salivary ducts and the intestine.
639
What segments of the nephron are involved in calcium and phosphate transport?
* Proximal Convoluted Tubule (PCT) * Thick Ascending Limb of the Loop of Henle * Distal Convoluted Tubule (DCT) and Connecting Tubule (CNT) * Collecting Duct (CD)
640
How is calcium reabsorbed in the PCT?
* Paracellular pathways via passive diffusion * Transcellular pathways via calcium channels and transporters
641
What transporters facilitate phosphate reabsorption in the PCT?
Sodium-dependent phosphate co-transporters.
642
What occurs in the thick ascending limb regarding calcium?
Minimal calcium reabsorption occurs mainly through paracellular pathways.
643
What is the role of PTH in the DCT and CNT?
Stimulates calcium reabsorption by increasing calcium channel activity.
644
What is the phosphate handling in the DCT and CNT?
Minimal reabsorption; primarily phosphate secretion.
645
How do hormones like PTH and calcitonin affect calcium handling in the CD?
They modulate the activity of calcium channels and transporters.
646
What is the main process for phosphate excretion?
Occurs in the urine under the influence of PTH and FGF23.
647
What is the primary function of buffer systems in the body?
To maintain acid-base homeostasis by minimizing changes in hydrogen ion (H+) concentration.
648
List the major buffer systems in the body.
* Carbonic Acid-Bicarbonate Buffer System * Protein Buffer System * Phosphate Buffer System * Ammonia Buffer System * Bone Buffer System
649
Where is the Carbonic Acid-Bicarbonate Buffer System primarily located?
In the extracellular fluid (ECF), including blood plasma.
650
What is the importance of the Carbonic Acid-Bicarbonate Buffer System?
It is one of the most important regulators of blood pH, involving the reversible reaction between carbonic acid (H2CO3) and bicarbonate ions (HCO3-).
651
How do protein buffers function?
They contain amino acid residues that can accept or donate H+ ions, helping to maintain pH stability.
652
Where is the Phosphate Buffer System primarily found?
In the intracellular fluid (ICF) and renal tubular fluid.
653
What role do phosphate ions play in the Phosphate Buffer System?
They act as weak acids and bases, buffering changes in pH by accepting or donating H+ ions.
654
Where is the Ammonia Buffer System primarily located?
In the renal tubular fluid and urine.
655
How does the Ammonia Buffer System function?
Ammonia (NH3) accepts H+ ions to form ammonium ions (NH4+), regulating urinary pH.
656
What is the significance of the Bone Buffer System?
Bone acts as a reservoir for alkaline salts that can neutralize excess H+ ions in the bloodstream.
657
What is the first task of the kidneys in acid-base balance?
To reabsorb most of the filtered bicarbonate.
658
Where does the reabsorption of bicarbonate primarily occur?
In the proximal tubule.
659
What is the major route for bicarbonate reabsorption?
An acid-base process involving the secretion of hydrogen ions.
660
What enzyme catalyzes the generation of hydrogen ions and bicarbonate from CO2 and water?
Carbonic anhydrase.
661
How do hydrogen ions get secreted into the tubular lumen?
In exchange for sodium via an antiporter or via a primary H-ATPase.
662
What is the role of the Na-H antiporter (NHE3) in the proximal tubule?
It mediates hydrogen ion secretion and sodium uptake.
663
What defines glomerulotubular balance?
The intrinsic ability of renal tubules to adjust their reabsorption rates according to changes in the filtered load.
664
How does hydrostatic pressure in the peritubular capillaries affect reabsorption?
Higher hydrostatic pressure facilitates the reabsorption of water and solutes.
665
What metabolic processes generate acids in the body?
* Carbohydrate metabolism * Fat metabolism * Protein metabolism
666
What is the fruit juice paradox in terms of metabolism?
The metabolism of acidic substances like citrus fruit can alkalinize the blood.
667
What condition can renal diseases lead to regarding acid-base balance?
Acidosis due to impaired excretion of hydrogen ions or reabsorption of bicarbonate.
668
What is renal tubular acidosis?
A condition that impairs the kidneys' ability to excrete acid or regenerate bicarbonate.
669
What triggers compensatory responses in acid-base physiology?
Disruptions in acid-base physiology
670
What is the renal response to acidosis?
Increase reabsorption of bicarbonate ions (HCO3-) and increase secretion of hydrogen ions (H+)
671
What is the renal response to alkalosis?
Decrease bicarbonate reabsorption and decrease hydrogen ion secretion
672
How does the respiratory system respond during acidosis?
Increases the rate and depth of breathing (hyperventilation)
673
What effect does hyperventilation have on blood CO2 levels?
Decreases CO2 levels
674
What is the respiratory response during alkalosis?
Decreases respiratory rate and depth (hypoventilation)
675
What happens to CO2 levels during hypoventilation?
Increases CO2 levels
676
What are the two main compensatory mechanisms for acid-base balance?
* Renal response * Respiratory response
677
Which compensatory response occurs more rapidly?
Respiratory response
678
Which compensatory response is slower but more powerful?
Renal response
679
What are the four categories of acid-base disorders?
* High pCO2: respiratory acidosis * Low pCO2: respiratory alkalosis * Low bicarbonate: metabolic acidosis * High bicarbonate: metabolic alkalosis
680
What is the Henderson-Hasselbalch equation used for?
To show the relationship between pH, bicarbonate, and PCO2
681
What indicates a primary uncompensated disorder?
Change in either PCO2 or bicarbonate concentration
682
What happens in respiratory acidosis due to low alveolar ventilation?
Increase in PCO2 and decrease in pH
683
How do healthy kidneys respond to increased PCO2 in respiratory acidosis?
Contribute new bicarbonate to the blood
684
What occurs in respiratory alkalosis regarding PCO2?
Decreased PCO2 and increased extracellular pH
685
What is the renal response to metabolic acidosis?
Produce more bicarbonate to return pH toward normal
686
How do kidneys respond to an acid load?
Reabsorb all filtered bicarbonate and increase formation and excretion of NH4+ and titratable acid
687
What indicates that kidneys are the cause of acid-base imbalance?
Bicarbonate concentration remains low despite renal response
688
Fill in the blank: In respiratory alkalosis, bicarbonate is _______ from the body.
lost

BMS 250 test 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions