module 2 - respiratory system Flashcards
(75 cards)
1
Q
what is external respiration?
A
The movement of gases between the environment and the cells of the body.
2
Q
what is ventilation (V)
A
The exchange of the air between the atmosphere and the lungs.
3
Q
what is internal respiration?
A
The movement of the gases from the lungs, through the bloodstream, and to the cells.
4
Q
what are the divisions of the RS and what do they include?
A
The upper respiratory system consists of the nose, pharynx, and associated structures
The lower respiratory system consists of the larynx, trachea, bronchi, and lungs
5
Q
structure and functions of the nasal cavity
A
- nasal conchae (superior, middle, and interior) - warm, humidify, filter, olfaction
- nasal meatuses (superior, middle, and interior) - direct airflow, olfaction, drain mucous and tears, resonance speech
- nasal vestibule - hair and sebaceous gland for protection and filtering, warming and humidifying, sensing touch and temperature
- tubal tonsil - immune and lymphatic drainage
- uvula - stops food moving into the nasal cavity, speech, and articulation, salivary glands, immune
- soft and hard palate - close off the nasal passages during swallowing and speech, help make m and n sounds
- olfactory epithelium and nerves - Olfactory receptor neurons: responsible for detecting odours and transmitting the sense of smell to the brain.
6
Q
structure and functions of the pharynx
A
Nasopharynx
- pharyngeal tonsil (Also known as adenoid)
- tubal tonsil
oropharynx
- palatine tonsil
- isthmus of the fauces - The passage that connects the oral cavity to the oropharynx.
laryngopharynx
- Food and air passage, protective sensory receptors
lingual tonsil
7
Q
external structures of the upper RS
A
body of hyoid bone - anchor point for muscles needed for swallowing and speech
jugular notch - used mechanically to assess venous pressure, inserting central venous catheter, observing the thyroid gland, radiological measurements
8
Q
structure and functions of the larynx
A
epiglottis
- Prevents food and liquids
from entering the airway
9
Q
structure and functions of the trachea
A
Flexible, slightly rigid tube in mediastinum
* Runs from end of larynx (C6) to T4/T5, where it bifurcates into the primary bronchi * Function: filter, warm, humidify air * Contains 15-20 U-shaped hyaline cartilages & trachealis muscle posteriorly
* Annular ligaments connect cartilage rings
mucosa
- pseudostratified ciliated columnar epithelium
- lamina propria (connective tissue)
submucosa
- seromucous gland in submucosa
hyaline cartilage
adventitia
10
Q
what are cilia
A
microscopic, hair-like, made of specialized protein structures and can move rhythmically – known as the “ciliary escalator.”
11
Q
name the 3 pleura membranes and their functions
A
Visceral Pleura: Covers the surface of the lungs
* Protects from friction
* Helps maintain shape
* Prevent lung collapse
* Synchronising movement with the chest wall
Parietal Pleura: Lines the thoracic cavity
* Covers not only the lungs but heart and major blood vessels
* Protects from friction
* Integrity of pleural cavity
Pleural Cavity: Contains Pleural Fluid (25mL): * creates a moist, slippery surface – easy sliding and ↓ friction * holds the lungs tight against the thoracic wall.
12
Q
describe bronchial circulation
A
Component of the systemic circulation. It consists of tiny bronchial arteries and veins that supply the bronchi and bronchioles of the lung
* Bronchial arteries branch from the anterior wall of the descending thoracic aorta and supply structures in the bronchial tree
* Larger bronchial veins
* collect venous blood and drain into the azygos and hemiazygous systems of veins
13
Q
lung structure
A
left main (primary) bronchus
lobar (secondary) bronchus
segmental (tertiary) bronchus
14
Q
There is a blockage in the Right Lobar Bronchus. What is the consequence of this?
A
less oxygen would move inalveol= less CO2 leaving, less oxygen in blood overall = tired, cold, dizzy
15
Q
bronchioles
A
- Hyaline cartilage is replaced by smooth muscle (keep them open)
- Terminal bronchioles branch
into respiratory bronchioles - Respiratory bronchioles branch
into alveolar ducts & alveoli
16
Q
alveolus function and pneumocyte types
A
Perfusion (Q): delivering blood to tissues and organs in the body
pneumocytes
Type 1
* Simple squamous epithelial cells.
* Form the walls of the respiratory membrane
Type 2
* Simple Cuboidal epithelial cells
* Produce surfactant
Alveolar Macrophages
* Resident immune cells
* Phagocytose pathogens
17
Q
respiratory muscles of inhalation
A
sternocleidomastoid, scalenes, external intercostals, diaphram
18
Q
respiratory muscles of exhalation
A
internal intercostals, external oblique, internal oblique, transversus abdominis, rectus abdominis
19
Q
what is Eupnea
A
Quiet breathing at rest. It can be diaphragmatic or costal
20
Q
what is diaphragmatic breathing
A
deep breathing - Diaphragmatic contraction expands the thoracic cavity
Exhalation is passive. The diaphragm relaxes
21
Q
what is Costal breathing
A
shallow breathing - Ext. Intercostal muscles contract, elevate the ribs and enlarge the thoracic cavity
Exhalation is passive. The muscles relax
22
Q
what is Hypereupnea
A
Fast-forced breathing
23
Q
describe Inspiration
A
Accessory muscles assist external intercostal muscles to elevate the ribs and enlarge the thorax
* Scalene muscles (elevate 1stand 2ndribs)
* Serratus anterior and posterior
* Pectoralis minor and major
* Sternocleidomastoid
24
Q
describe exhalation
A
Internal intercostal muscles depress the ribs
At very rigorous breathing: Exhalation Abdominal muscles compress abdominal contents & reduce the volume of the thoracic cavity
* External and internal obliques
* Transversus abdominis
* Rectus abdominis
25
explain Boyle's Law
the volume of a gas and pressure are inversely proportional at a given temperature (e.g., body
temperature).
- gases move from a higher pressure to a lower pressure
- decrease V = increased P
26
what are the 3 types of pressure? and explain them
Intrapulmonary pressure
* the pressure in the alveoli (also known as alveolar pressure)
* Inspiration -> increase lung volume -> decrease pressure -> less than the atmosphere -> air in
* Expiration -> ↓ lung volume -> increase pressure -> air out
Intrapleural pressure:
* Generally lower than the intrapulmonary and atmospheric pressures.
* Keep the lungs inflated and allow them to adhere to the chest wall, enabling efficient breathing.
* ↑ lung volume -> smaller intrapleural space -> increase pressure
* ↓ lung volume -> larger intrapleural space -> decrease pressure
Transpulmonary (transmural) pressure: the difference between these
* Always positive because the pressure inside the lungs is normally higher than the pressure
27
how do changes in transpulmonary pressure lead to changes in lung size
How much the lung and chest wall can stretch (distensibility).
Thin elastic band = Easily stretched (compliance)
Thick elastic band = Not easily stretched (low compliance)
High compliance: lungs and chest wall expand easily with each breath in, so it takes less effort to breathe.
Low compliance: they're stiffer and it takes more effort to fill them with air.
28
what is airway resistance and what is it related to?
The resistance (opposition/ hindrance) to the flow of air through the respiratory tract during the process of breathing.
It's a measure of how much effort is required to move air in and out of the lungs.
Related to
* Length
* Radius
* Cross-sectional area of the airways
* Bronchodilation
* Bronchoconstriction
* Density, viscosity (does not really change too much)
* Velocity of the gas
29
explain the role of pressure gradient & airway resistance
Airflow (F) is the volume of air flowing through the lungs at any point in time, It is directly proportional to the pressure gradient between the external atmosphere & alveoli, & inversely proportional to the resistance of airway passages:
F ∝ ΔP / R
* The volume of air that moves into or out of the lungs at any given point in time. ΔP= pressure gradient
* The difference in air pressure between two points e.g., external atmosphere and the alveoli R= resistance
* the opposition or difficulty that the air encounters as it moves through the airway passage
30
what is elastic recoil?
After we take a breath in, the lungs want to return to their normal state.
The chest wall also has elastic recoil, but outwards, counteracting the inward elastic recoil of the lungs.
This is the opposite of compliance.
Thin elastic band Easily stretched (compliance) BUT not great recoil!
Thick elastic band Not easily stretched (low compliance) BUT
good recoil!
31
inspiration sequence of events
1. inspiratory muscles contract (diaphragm descends; rib cage rises)
2. thoracic cavity volume increases
3. lungs are stretched; intrapulmonary volume increases
4. intrapulmonary pressure drops (to - 1 mm Hg)
5. air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure)
32
expiration sequence of events
1. inspiratory muscles relax (diaphragm) rises; rib cage descends due to recoil of costal cartilages)
2. thoracic cavity volume decreases
3. elastic lungs recoil passively; intrapulmonary volume decreases
4. intrapulmonary pressure rises (to +1 mm Hg)
5. air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0
33
in terms of forces acting on the lungs, what is keeping the alveoli open?
Transmural Pressure Gradient
* The pressure inside the alveoli (the air you’ve breathed in), compared to the pressure in the pleural space (less than atmospheric pressure).
Pulmonary Surfactant
* Reduces the surface tension within the alveoli (discussed
today)
Alveolar interdependence
* If one alveolar in the middle is collapsing, those around it can stop this from happening due to their shared walls and connective tissue.
34
in terms of forces acting on the lungs, what is promoting alveolar collapse?
Alveolar Surface Tension
* The inward pull due to the polar water molecules.
Elasticity of stretch pulmonary connective tissue
* Recoil of the lungs and chest wall.
35
The exchange of oxygen (O2) and carbon dioxide (CO2) between the external environment and the body's cells through the respiratory system. Why do we need this?
cellular respiration - oxygen to cells so we can create ATP, a by-product of ATP is CO2 and we need to breath that out. if we don't out blood becomes acidic = unwell
36
describe the process of gas exchange: external respiration
* Occurs in the lungs
* Oxygen (O2) is delivered from the alveoli to the pulmonary capillary
* Carbon dioxide (CO2) is delivered to
the alveoli from the pulmonary capillary
37
describe the process of gas exchange: internal respiration
* Occurs at the cellular level
* Oxygen (O2) is delivered from the bloodstream to the body's tissues and cells.
* Carbon dioxide (CO2) produced by cellular metabolism, moves from the cells into the bloodstream
38
describe external respiration type 1 cells and how these cells help gas exchange
Type 1 (alveolar cells/ pneumocyte)
* Simple squamous epithelial cells.
* Form the walls of the respiratory membrane
Fick's law of diffusion:
The shorter the distance through which diffusion must take place,
the greater the rate of diffusion
The greater the surface area across which diffusion can take place, the greater the rate of diffusion
-> that's why they're so thin and aid gas exchange
39
describe external respiration type 2 cells and how these cells help gas exchange
type 2
* Simple Cuboidal epithelial cells
* Produce surfactant -> keeps alveolar open and polarity causes network of bonds (hydrogen bonds) -> makes them really attracted and sticky
40
what is surfactant and what role does it play
A detergent-like mixture of phospholipids, surfactant proteins, and neutral lipids - it is amphiprotic (some of it is non-polar and another part is polar).
Decreases water cohesiveness
Reduces surface tension of alveolar fluid, & reduces tendency to recoil (alveolar collapse)
Surfactant reduced alveolar tension in smaller alveoli more than
larger alveoli
41
explain Dalton's Law
Each gas has its own partial pressure, based upon its concentration in the solution. The sum of these is the overall pressure. i.e., the total pressure of the air in your lungs is the sum of the pressures each of these gases would exert if they were alone.
42
explain Henry's Law
the amount of dissolved gas in a liquid (blood) is proportional to the partial pressure above the liquid.
43
what does gas exchange mean and what 3 factors impact/ aid it
O2 & CO2 need to move between lungs & other body cells transported in blood & exchanged by passive diffusion
1. Partial pressure gradient (Dalton’s and Henry’s Law)
2. Thickness & surface area of exchange membranes (Fick’s Law)
3. Ventilation-perfusion coupling (V/Q)
44
what is Ventilation-perfusion coupling (V/Q)
when ventilation < perfusion = pulmonary arterioles constrict and bronchioles dilate = decreased perfusion and increased ventilation
when ventilation > perfusion = pulmonary arterioles dilate and bronchioles constrict = increased perfusion and decreased ventilation
45
summarise gas transport: O2 in
1. Ventilation of the lungs.
2. Diffusion of oxygen from the alveoli into the blood in the pulmonary capillaries.
3. Perfusion of systemic capillaries with oxygenated blood.
4. Diffusion of oxygen from systemic capillaries into the cells
46
summarise gas transport: CO2 out
1. Diffusion of carbon dioxide from the cells into the systemic capillaries.
2. Perfusion of the pulmonary capillary bed with deoxygenated blood.
3. Diffusion of carbon dioxide into the alveoli.
4. Removal of carbon dioxide from the lungs by ventilation.
OPPOSITE OF O2 IN
47
How does hemoglobin aid gas transport?
* Haemoglobin (Hb) molecule consists of four protein chains called globins
* Each globin chain is attached to a heme group that contains an iron atom.
* Each iron atom has the capacity to bind with one molecule of oxygen.
48
how is oxygen transported?
Only approximately 1.5% of inhaled O2
is dissolved in blood plasma
* This is what diffuses into cells
About 98.5% of blood O2 is bound to iron in haemoglobin.
– Oxyhaemoglobin
When all Hb is converted to oxyhaemoglobin (Hb–O2) ->
Hb is fully saturated.
* Partial saturation occurs with a mix of Hb and Hb–O2.
49
how is CO2 transported?
CO2is carried as:
* Bicarbonate ions (70%)
* Carbaminohemoglobin (20%) - where it binds to amino groups in haemoglobin
* Dissolved in plasma (10%).
50
explain what Haldane effect in the tissues and lungs
The binding or release of one oxygen molecule changes the conformation or shape of the haemoglobin molecule, making it easier for the subsequent oxygen molecules to be released.
1. In the tissues:
Oxygen is released from haemoglobin = increased capacity to bind with carbon dioxide and protons (forming bicarbonate) -> removes these from tissues.
2. In the lungs:
Oxygen binds to haemoglobin = decreased capacity to bind with carbon dioxide and protons -> release to be exhaled
51
how does pH impact gas transport?
The Bohr effect:
A lower pH (more acidic conditions) -> increase of O2 from hemoglobin -> promotes CO2 binding.
52
how does temperature impact gas transport?
* Higher temperatures promote the release of O2
* ↑ oxygen to actively metabolizing tissues, where heat is generated
53
how does 2,3-BPG impact gas transport?
* Binds to haemoglobin
* Reduces affinity for O2
* ↑ oxygen release
54
how is breathing regulated?
* Respiratory muscles contract only when stimulated by nerves
* Rhythmic breathing is established by cyclic neural activity from the brainstem to respiratory muscles
(although origin of this rhythm not well understood)
* Maintains breathing & reflex adjustments when required
* Can be voluntarily modified
55
what are the neural mechanisms that control breathing and what do they do
Neurons in the Medulla Oblongata:
* Nucleus tractus solitarius (NTS) contains the Dorsal Respiratory Group (DRG) - control the muscles of respiration, particularly for inspiration. * Ventral Respiratory Group contains the Pre-Botzinger Complex - spontaneous firing neurons: basic pacemaker of respiratory system. Also, controls muscles for active breathing.
There is also the Pons Respiratory Centre:
- fine-tunes breathing during activities such as talking, sleeping, exercise
- integrates inputs from peripheral sensory receptors & higher brain centers
- communicate & modifies DRG & VRG neurons
56
In terms of afferent signaling to the medulla, what excitatory and inhibitory stimuli are the respiratory centres sensitive to?
* Chemical factors: arterial CO2, H+, O2
via central & peripheral chemoreceptors
* Inflation reflex: stretch receptors signal respiratory centres via vagal nerve afferents to end inspiration & lungs recoil
* Pulmonary irritants: mucus, dust, fumes stimulate bronchiole receptors that communicate with respiratory centres via vagal nerve afferents -> Reflex constriction, cough, sneeze
* Higher brain centres: hypothalamus (emotions & pain) & motor cortex (voluntary control)
57
what are the 3 chemoreceptors and what do they do in relation to afferent signaling
Carotid body chemoreceptors:
* Nerve fibers pass to the glossopharyngeal nerves and to the DVG.
* High blood flow
* Detects
* ↓ PaO2 (hypoxemia) (60 down to 30 mm Hg)
* No change in ventilation until < 20 mm Hg
* Insensitive to ↑ PaO2 above 50–60 mm Hg.
Aortic body chemoreceptors:
* Nerve fibers pass through the vagus nerve, and to the DVG.
* Lower blood flow
* Detects
* ↓ PO2 (hypoxemia)
* ↑ PCO2 (hypercapnia)
* ↑ H+ (this does what to pH
Central chemoreceptors:
* In Medulla oblongata
* Detects in CSF
* ↑ PCO2 (hypercapnia)
* ↑ H+ (this does what to pH
58
what are stretch receptors and what do they do in relation to afferent signaling
Located in the walls of the airways in the lungs, these receptors detect
the degree of lung inflation. Nerve impulses via the vagus nerve
If the lungs become over-inflated, the stretch receptors send inhibitory signals to the medulla -> temporary halt in inspiration
59
what are nociceptors and what do they do in relation to afferent signaling
Sensory nerve endings that respond to noxious or harmful stimuli.
Activated by inhaled irritants:
* Chemicals
* Temperature Extremes
* Mechanical Injury
* (and Inflammation)
Activation results in sensations of pain or discomfort and might induce reflexes like constriction, cough, sneeze.
For some reflexes, the spinal cord acts as the integration center – this does not reach the medulla oblongata.
60
where are afferent signals interpreted?
medulla oblongata
61
what systems could be activated once afferent signals are interpreted by the medulla oblongata?
* Sympathetic Nervous System Activation
* Parasympathetic Nervous System Activation
62
how is that sympathetic system activated by afferent signals and once activated what does the SNS do? (efferent response)
SNS responding to some sort of stressor -> activate afferent signal to signal to medulla oblongata -> interpret as threat -> SNS activated
released neurotransmitter (noradrenaline) -> activating something in respiratory system to increase rate and depth of respiration -> related to contraction of muscles that open airways
changes air coming in -> gas pressure change -> gas exchange -> amount of O2 in blood....
63
what does the peripheral NS do in response to afferent signals? (efferent response)
- releases acetylcholine
- Reduces the heart rate and respiratory rate.
64
define the depth of breathing and what determines the depth
* How much air is inhaled or exhaled during a single breath (tidal volume).
* Determined by degree of neuronal stimulation from respiratory centres
↑ stimulation of inspiratory neurons
↑ force of respiratory muscle contraction resulting in greater thoracic expansion
65
define the rate of breathing and what determines the rate
* The number of breaths taken in a minute
* Determined by how long the inspiratory neurons are active.
* If they're active for a more extended period, inhalation will last longer, leading to a slower breathing rate
* If they're active for a shorter time, the breathing rate will be faster.
66
how do we regulate breathing during exercise?
Ventilation
↑ 10-20-fold during vigorous exercise due to ↑ tidal volume & respiratory rate: 4L/min to 80L/min
Greater force of contraction of respiratory muscles & activation of accessory muscles that further ↑ thoracic volume
How?
* ventilation ↑ as soon as exercise begins & arterial PCO2 & PO2 remain relatively constant (although capillary & venous levels change)
* Psychological – anticipation of exercise
* Simultaneous cortical motor & respiratory centre activation
* Proprioceptors in active muscles, tendons, & joints stimulate respiratory centers
67
what are the causes, consequences, and treatment for Obstructive Sleep Apnoea?
Upper airway obstruction during sleep
caused by:
* Neck circumference, caused by a number of factors such as
– Excess weight (10% weight gain ↑ risk by x 6)
– Obstruction due to muscles or glands
– Anatomy
* Hypothyroidism
* Excess growth hormones
* Smoking
* Alcohol or drug abuse
Consequences:
* Increased risk of
– Hypertension
– Stroke
– Heart attack – Diabetes
– GORD
– Heart failure
– Arrythmias Respiratory Diseases
Treatment: CPAP, Mild air pressure to keep breathing airways open during sleep.
68
what are the causes, consequences, and treatment of cystic fibrosis?
Cause:
* Autosomal recessive multisystem disease
* Mutation in the CFTR gene, located on chromosome 7.
* Must inherit two faulty CFTR genes (one from each parent)
* Defective epithelial chloride ion transport (CFTR channel)
- Chloride can’t move out of cells
- Decreased Na+ and H2O movement - - Dehydration of mucous
- Thick and sticky
consequences:
* Impaired cilia
* Trapped pathogens that can’t be cleared
* Airway obstruction
* Chronic inflammation -> hyperplasia of goblet cells, bronchiectasis, pneumonia, hypoxia, fibrosis
treatment: Pancreatic enzyme supplements, high-calorie diet, aerosolised DNAse, antibiotics, chest physio, lung transplantation
69
what are the causes, consequences, and treatment of asthma?
* Chronic inflammatory disorder of the airways
* Inflammation results from hyperresponsiveness of the airways
* Can lead to obstruction and status asthmaticus Symptoms include: expiratory wheezing
* Dyspnoea
* Tachypnoea
* Cough
* Chest tightness
Peak flow meters used to monitor
can lead to
Obstructive
Conditions where airflow is impeded, making it hard to exhale all the air in the lungs.
Narrowing or blockage of the airways. e.g., * Chronic Bronchitis
* Emphysema
* Collectively called Chronic Obstructive Pulmonary Disorder (COPD)
* Asthma
Restrictive
Conditions where the lungs cannot fully expand in volume.
Often due to stiffness in the lungs or weakness in the chest wall muscles. e.g.,
* Pulmonary fibrosis
* Sarcoidosis
* Chest wall deformities.
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