Bio Final Flashcards
(247 cards)
1
Q
Immune system
A
the bodies protection system
includes 2 subsections
-> Innate (non specific)
-> adaptive (specific and memory)
a complex collection of cells and organs that destroys or neutralized pathogens
2
Q
Adaptive immune system
A
specific and memory
- humoral (antibodies)
- cellular (APCs - antigen presenting cell)
slow response -> 4-14 days
3
Q
Innate immune system
A
non specific
- physical (barriers)
- cellular(agranulocytes and granulocytes)
- chemical (substance in secretions)
fast response -> 0-4 hours
4
Q
Innate immune cells
A
- natural killer cell (large granular lymphocyte)
- basophil
- neutrophil
- eosinophil
- monocyte -> macrophage
5
Q
adaptive immune cells
A
small lymphocyte
-> T lymphocyte
-> B lymphocyte -> plasma
cell
6
Q
adaptive immunity
A
an acquired defense against foreign pathogens that is characterized by specificity and memory
first exposure to an antigen stimulates a primary response -> subsequent exposures stimulate a faster and stronger secondary response
a dual system involving humoral immunity and cellular immunity
7
Q
antigen
A
aka immunogens
a foreign molecule that will trigger an immune response
molecules that activate adaptive immunity
a single antigen possesses smaller epitopes, which are each capable of inducing a specific adaptive immune response
its ability to stimulate an immune response depends on is molecular class, complexity, and size
8
Q
humoral immunity
A
part of adaptive immunity
it is antibodies produced by B cells
9
Q
cellular immunity
A
part of adaptive immunity
it is T cells that are directed against intracellular pathogens
10
Q
T cells
A
attack infected cells
11
Q
B cells
A
attack invaders outside the cells
12
Q
epitopes
A
the part of the antigen that antibodies attaches to
13
Q
major histocompatibility complex (MHC)
A
a collection of genes coding for glycoprotein molecules expressed of the surface of all nucleated cells
are essential for the presentation of normal “self” antigens
14
Q
MHC I
A
cells that become infected by intracellular pathogens can present foreign antigens on MHC I -> marking the infected cell for destruction
15
Q
MHC II
A
MHC II molecule are expressed only on the surface of antigen-presenting cells (macrophages, dendritic cells, and B cells)
antigen presentation with MHC II is essential for the activation of T cells
16
Q
Antigen-presenting cells (APCs)
A
- macrophages
- dendritic cells
- B cells
ingest pathogens by phagocytosis, destroy them in the phagolysosomes, process the protein antigens, and select the most antigenic/immunodominant epitopes with MHC II for presentation to T cells
17
Q
T cell maturation process
A
immature T lymphocytes are produced in red bone marrow -> travel to the thymus for maturation -> undergoes thymic selection which is a 3 step process of negative and positive selection that determines which T cells will mature and enter the peripheral bloodstream
18
Q
thymus
A
located behind the sternum
different from the thyroid
19
Q
Central tolerance
A
involves the negative selection of self-reactive T cells in the thymus
20
Q
Peripheral tolerance
A
involves the anergy and regulatory T cells that prevent self-reactive immune responses and autoimmunity
21
Q
Helper T cells
A
activation = APCs presenting antigens with MHC II
functions = orchestrate humoral and cellular immunity and are involved in the activation of macrophages and NK cells
CD4
22
Q
Regulatory T cells
A
activation = APCs presenting antigens associated with MHC II
functions = involved in peripheral tolerance and prevention of autoimmune responses
CD4
23
Q
Cytotoxic T cells
A
activation = APCs or infected nucleated cells presenting antigens associated with MHC I
function = destroy cells infected with intracellular pathogens
CD8
once activated they target and kill cells infected with intracellular pathogens
-> requires recognition of specific pathogen epitomes presented on cell surfaces using MHC I molecules
Killing is mediated by perforin and granzymes that induce apoptosis
24
Q
T-Cell Receptor (TCR)
A
similar in structure to immunoglobulins, but less complex
millions of unique epitope- binding TRCs are encoded
25
Immunoglobulins
aka antibodies
are glycoproteins produced by plasma cells
are Y-shaped glycoproteins with two Fab sites (V part of the Y) for binding antigens and an Fc portion (I portion of the Y) involved in complement activation and opsonization (makes a foreign cell more susceptible to phagocytosis)
26
classes of T cells
can be divided into 3 classes
- helper T cells
- cytotoxic T cells
- regulatory T cells
based on their expression of CD4 or CD8, the MHC molecules they interact with for activation and their respective funcitons
27
CD4
a glycoprotein that serves as a co-receptor for the T cell receptor
lead the fight against infections
28
CD8
a transmembrane glycoprotein that serves as a co-receptor for the T cell receptor
can kill cancer cells and other invaders
29
Activated helper T cells
differentiate into TH1, TH2, TH17, or memory T cell subtypes
differentiation is directed by the specific cytokines to which they are exposed
30
TH1, TH2, TH17
perform different functions related to the stimulation of adaptive and innate immune defenses
TH1 = stimulates cytotoxic T cells and produce memory cytotoxic T cells, stimulates macrophages and neutrophils for more effective killing of pathogens, and stimulates NK cells to kill more effectively
TH2= stimulate B cell activation and differentiation into plasma cells and memory B cells, direct antibody class switching in B cells
TH17= stimulate immunity to specific infections such as chronic mucocutaneous infections
31
Memory T cells
are long lived cells that can respond quickly to secondary exposures
remember a specific pathogen and mount a strong, rapid, secondary response upon re-exposure
32
Perforin
responsible for pore formation in cell membranes of target cells -> punch holes into the target cell membrane
33
Granzymes
induce the the death of virus-infected and other potentially harmful cells
34
Apoptosis
a type of cell death in which a series of molecular steps in a cell lead to its death
the process of programmed cell death
35
B cell maturation process
B cells are produced in the bone marrow, where the initial stages of maturation occur -> move to the spleen for the final steps of maturation into naive mature B cells
B cells produce antibodies involved in humoral immunity
36
5 classes of antibody
- IgM = 10 antigen binding sites
- IgG = 2 antigen binding sites
- IgA = 4 antigen binding sites
- IgE = 2 antigen binding sites
- IgD = 2 antigen binding sites
each differs in size, arrangement, location within the body, and function
37
5 primary functions of antibodies
- neutralization
- opsonization
- agglutination
- complement activation
- antibody-dependent cell-mediated cytotoxicity (ADCC)
38
opsonization
makes a foreign cell more susceptible to phagocytosis
39
antibody-dependent cell-mediated cytotoxicity (ADCC)
A type of immune reaction in which a target cell or microbe is coated with antibodies and killed by certain types of white blood cells
40
B cell receptors (BCRs)
membrane-bound monomeric forms of IgD and IgM that bind to specific antigen epitopes with their Fab antigen binding regions
41
T-dependent antigens
protein antigens that can only activate B cells with the cooperation of helper T cells
involves processing and presentation of protein antigens to helper T cells, activation of the B cells by cytokines secreted from activated TH2 cells, and plasma cells that produce different classes of antibodies as a result of class switching
memory B cells are also produced
42
T-independent antigens
molecule classes that do not require T cell cooperation to active B cells
43
Cytokines
when TH2 cells are activated they secrete specific signalling molecules called cytokines-> they play a crucial roles in activating B cells
facilitate various nonspecific responses by innate immune cells
play a key role in the inflammatory response -> phase proteins, histamine, leukotrienes, prostaglandins, and bradykinin
44
class switching
aka isotype switching
B cells change the class of antibodies they produce while maintaining the same antigen specificity, this allows for the production of antibodies of different classes
45
secondary exposures to T-dependent antigens
results in a secondary antibody response initiated by memory B cells
develops more quickly and produces higher and more sustained levels of antibody with higher affinity for the specific antigen
46
lymphatic system
a system of vessels, cells, and organs that carries excess fluid to the bloodstream, and filters pathogens from the blood
blood pressure causes leakage of fluid from the capillaries -> interstitial space -> lymph
47
lymph
immune cells and dietary fats
lymph is forced through the lymphatic vessels by the movements of the body, contraction of skeletal muscles, and breathing
48
pathway of the cells of the immune system
cells of the immune system use lymphatic vessels to make their way from interstitial spaces back into the circulation
and use lymph nodes as major staging areas for the development of critical immune responses
49
lymph node
a small, bean-shaped organ located throughout the lymphatic system
found commonly near the groin, armpits neck, chest, and abdomen
50
lymphatic vessels
one way valves (semi-lunar) in the vessels keep lymph moving forward toward the heart
51
movement of lymph
interstitial pressure increases -> flaps open -> lymph -> lymphatic capillaries -> lymphatic vessels -> dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck
52
chyle
in the small intestine, dietary triglycerides combine with other lipids and proteins and enter the lacteals (the lymphatic vessels of the small intestine) to form a milky fluid called chyle
chyle travels through the lymphatic system and will eventually enter the bloodstream
essential for immune function as is transports immunoglobulins and T lymphocytes through the body
53
lymphatic ducts
superficial and deep lymphatics merge to form larger vessels called lymphatic trunks
54
What drains into the right lymphatic duct
the right sides of the head, thorax, and right upper limb drain lymph fluid into the right subclavian vein via the right lymphatic duct
55
what drains into the thoracic duct
the left side of the body drains into the larger thoracic duct, which then drains into the left subclavian vein
56
lymphoid organs
are where lymphocytes mature, proliferate, and are selected = attack pathogens without harming the cells of the body
57
primary lymphoid organs
- bone marrow
- thymus gland
58
secondary lymphoid organs
- lymph nodes (lymph filters)
- spleen (blood filter)
- lymphoid nodules
59
lymphoid nodules
occur most typically in the cortex of lymph nodes (outer layer), in the spleen, tonsils
60
physical barriers
- the skin
- endothelia
- cell junctions
- mucociliary escalator (transports mucus with any captured foreign particles in an upstream direction towards the upper airway away from the alveoli)
61
mechanical defences
microbes trapped are removed from the body by mechanical actions -> shedding skin cells, mucociliary sweeping, coughing, peristalsis, flushing of bodily fluids
62
microbiome
the resident microbiota provide a physical defense by occupying available cellular binding sites and competing with pathogens for available nutrients
63
nonspecific innate immune defenses
- physical barriers
- mechanical defences
- microbiome
- chemicals and enzymes in body fluids
- antimicrobial peptides (AMPs)
- plasma protein mediators
- cytokines
- inflammation-eliciting mediators
- granulocytes
- agranulocytes
64
chemical and enzymes in body fluids
chemical mediators like sebum, saliva, mucus, gastric and intestinal fluids, urine, tears, cerumen, and vaginal secretions are found in body fluids
65
antimicrobial peptides (AMPs)
AMPs found on the skin and in other areas of the body are largely produced in response to pathogens
66
plasma protein mediators
plasma contains various proteins that serve as chemical mediators -> acute-phase proteins, complement proteins, and cytokines
67
complement protein system
The complement system is made up of a large number of distinct plasma proteins that react with one another to opsonize pathogens and induce a series of inflammatory responses that help to fight infection
involves many precursor proteins that circulate in plasma
these proteins become activated in a cascading sequence in the presence of microbes -> results in the opsonization of pathogens, chemoattraction of leukocytes, induction of inflammation, and cytolysis (disruption of cells) through the formation of a membrane attack complex
68
membrane attack complex (MAC)
forms pores in the plasma membrane of pathogens or targeted cells, leading to osmolysis (rupture of cell)
69
Granulocytes
leukocytes characterized by a lobed nucleus and granules in the cytoplasm
include neutrophils, eosinophils, and basophils
70
neutrophils
leukocytes found in the largest numbers in the bloodstream
primarily fight bacterial infections
71
eosinophils and basophils
eosinophils target parasitic infections
eosinophils and basophils are involved in allergic reactions
both release histamine and other pro-inflammatory
72
agranulocytes
natural killer (NK) cells are lymphocytes that recognize and kill abnormal of infected cells by releasing proteins that trigger apoptosis (cell death by a series of molecular steps)
73
Fas ligand
a type II membrane protein that is involved in the regulation of cell death (apoptosis)
74
Monocytes
large, mononuclear leukocytes that circulate the bloodstream
may leave the the bloodstream and enter tissues where they differentiate and become tissue-specific macrophages and dendritic cells
75
inflammatory response
the hallmark of the innate immune response is inflammation
cardinal signs = pain, heat, redness, swelling, loss of function
brings fluid and cells to the site to destroy the pathogen and remove debris from the site, and isolates the site limiting the spread of the pathogen
76
Acute inflammation
short-term inflammatory response to an insult to the body
77
chronic inflammation
ongoing inflammation -> 2 months
78
4 parts of the inflammatory response
tissue injury -> the injured cells stimulate the release of mast cell granules and inflammatory mediators like histamine, leukotrienes, and prostaglandins
vasodilation -> increased blood flow allows for grater access of the blood to the site of inflammation, is responsible for the heat and redness of inflamed tissue
increased vascular permeability -> leakage of fluid into the interstitial space, results in swelling
recruitment of phagocytes -> leukotrienes attract neutrophils from the blood to the site of infection by chemotaxis, stimulating more macrophages to clean up the debris
79
effect of histamine
histamine released -> vasodilation -> increased blood flow -> plasma leaks out into interstitial fluid -> causes swelling
80
leukotrienes
attract neutrophils from the blood by chemotaxis and increase vascular permeability
81
prostaglandins
cause vasodilation by relaxing vascular smooth muscles and a major cause of pain associated with inflammation
82
2 divisions of the respiratory system
- the conducting zone
- the respiratory zone
83
conducting zone
consists of all of the structures that provide passageways for air to travel into and out of the lungs
the nasal cavity = the conchae and meatuses helps warm, filter, and humidify air
pharynx = the nasopharynx(by nose), oropharynx (by mouth), and laryngopharynx (this is in order going down toward the lungs)
trachea
bronci
84
conchae
projections of the ethmoid bones in the nose
curved shelf of bone
85
meatus
three spaces in the nasal cavity
86
respiratory zone
includes the structures of the lung that are directly involved in gas exchange
terminal bronchioles
alveoli
87
respiratory epithelium
pseudostratified ciliated columnar epithelium with goblet cells - trachea
mucus traps pathogens and debris, and cilia move the mucus superiorly toward the throat where it is swallowed
as the bronchioles become smaller and near the alveoli the epithelium thins and is simple squamous epithelium in the alveoli
88
respiratory membrane
the endothelium of surrounding capillaries and the alveolar epithelium = the respiratory membrane
this is a blood-air barrier through which gas exchange occurs by simple diffusion
89
lungs
the major organs of the respiratory system
responsible for performing gas exchange
paired and separated into lobes
right lung = 3 lobes
left lung = 2 lobed
90
parasympathetic and sympathetic control of the respiratory system
the lungs are controlled by the parasympathetic and sympathetic nervous systems -> bronchodilation and bronchoconstriction of airways
91
pleura membrane
the membrane that encloses the lungs
composed of visceral (closer to the lung) and parietal layers (closer to the chest wall), with the pleural cavity in between
the mesothelial cells of the pleural membrane create pleural fluid
92
pressure
Boyles law describes = as volume increases, pressure decreases
as volume decreases, pressure increases
pressure is influenced by resistance
93
direction of air flow
air flows from a space of higher pressure to a space of lower pressure
94
pulmonary ventilation
it is the process of breathing, driven by pressure differences between the lungs and the atmosphere
consists of the process of inspiration and expiration, air entering and leaving the lungs
95
atmospheric pressure
the force exerted by gases present in the atmosphere
96
intraalveolar (intrapulmonary) pressure
the force exerted by gases within the alveoli
760 mmHg
will equalize with atmospheric pressure
97
intrapleural pressure
the force exerted by gases in the pleural cavity
756 mmHg
98
transpulmonary pressure
intrapleural pressure is lower to intra-alveolar pressure, this difference is called transpulmonary pressure
760 mmHg - 756 mmHg = 4 mmHg
99
resistance
created by inelastic surfaces and the diameter of the airways
reduces the flow of gases
surface tension of the alveoli also influences pressure
100
pulmonary surfactant
helps reduced the surface tension so that the alveoli do no collapse during expiration
101
lung compliance
the ability of the lungs to stretch
plays a role in gas flow, the more the lungs can stretch the greater the potential volume of the lungs
the greater the volume of the lungs, the lower the air pressure within the lungs
102
inspiration
atmospheric pressure is positive and lung pressure is negative
103
expiration
atmospheric pressure is negative and lung pressure is positive
104
forced exhalation
the intercostal and abdominal muscled may be involved in forcing air out of the lungs
105
respiratory volume
describes the amount of air in a given space within the lungs and that can be moved by the lungs
dependent of a variety of factors
- tidal volume = quiet respiration
- residual = prevents collapsing
- inspiratory reserve = forcefully past tidal
- expiratory reserve = forcefully past tidal
106
respiratory capacity
the combination of 2 or more respiratory volumes
107
anatomical dead space
air within the respiratory structures that never participates in gas exchange, as it doesn't reach functional alveoli
108
respiratory rate
number of breaths taken per min
rate and depth are controlled by the respiratory centres of the brain -> medulla oblongata is stimulated by factors like chemical and pH changes in the blood
109
chemoreceptors of the respiratory system
changes in chemical and pH concentration in the blood are sensed by chemoreceptors
central chemoreceptors are located in the brain
peripheral chemoreceptors are located in the aortic arch and carotid arteries
110
apneustic center
in the pons
increases the depth and duration of inspiration
111
pneumotaxic centre
in the pons
decreased the depth and duration of inspiration
112
daltons law
states that each specific gas in a mixture of gases exerts force independently of other gases in the mixture
113
henrys law
states that the amount of a specific gas that dissolves in a liquid is a function of its partial pressure -> the greater the partial pressure of a gas, the more of that gas will dissolve in a liquid
114
gas molecules
move down a pressure gradient
partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries -> oxygen diffuses across the respiratory membrane into the blood
partial pressure of CO2 is high in the pulmonary capillaries and low in the alveoli -> CO2 diffuses across the respiratory membrane into the alveoli
115
external respiration
refers to gas exchange that occurs in the alveoli
116
internal respiration
refers to gas exchange that occurs in the tissue
117
perfusion
affects the flow of blood in the capillaries
118
transport of oxygen
is primarily transported through the blood by erythrocytes
blood cells contain a metalloprotein called hemoglobin -> composed of 4 subunits with a ring-like structure, each subunit contains one atom of iron bound to a molecule of heme
119
heme
binds oxygen so that each hemoglobin molecule can bind up to 4 oxygen molecules
when all heme units are bound to oxygen, the hemoglobin is saturated
partially saturated hemoglobin is when only some units are bound to oxygen
120
transport of CO2
3 different mechanisms
- dissolved carbon dioxide (10%)
- bicarbonate (70%)
- carbominohemoglobin (20%)
carbon dioxide + water + enzyme carbonic anhydrase -> carbonic acid -> spontaneously dissociates into bicarbonate and hydrogen ions
121
bicarbonate
as it builds up in erythrocytes, it moves across the membrane into the plasma in exchange for chloride ions by a mechanism called the chloride shift
122
polycythemia
elevated count of red blood cells due to chronic exposure to high altitudes
123
digestive system
includes the organs of the alimentary canal (aka the digestive tract) and accessory structures
alimentary canal forms a continuous tube that is open to the outside environment at both ends
organs include:
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
accessory structures:
- teeth
- tongue
- salivary glands
- liver
- pancreas
- gallbladder
124
tissue layers of the alimentary canal
inner to outer layers
- mucosa
-submucosa
-muscularis
-serosa
125
enteric nervous system
provided intrinsic innervation to the digestive system
126
autonomic nervous system
provides extrinsic innervation to the digestive system
127
myenteric plexus
aka plexus of Auerbach
is responsible for motility
stimulates the smooth muscles in the intestines
128
submucosal plexus
aka plexus of Meissner
responsible for regulating digestive secretions and reacting to the presence of food
129
blood supply in the digestive system
transport the protein and carbohydrate nutrients absorbed by mucosal cells after food is digested in the lumen
lipids are absorbed via lacteals
blood vessels' second function is to supply nutrients and oxygen
130
aortic arch and thoracic aorta (digestive system)
supply the more anterior parts of the intestines with branching arteries
131
abdominal aorta (digestive system)
supply the inferior alimentary canal with branching arteries
132
celiac trunk
supplies the liver, stomach, and duodenum with blood
133
superior and inferior mesenteric arteries
supply blood to the small and large intestines
134
6 activities of the digestive system
- ingestion
- motility/propulsion/peristalsis
- mechanical/physical digestion
- chemical digestion
- absorption
- defecation
these processes are regulated by neural and hormonal mechanisms
134
neuronal mechanisms of the digestive system
mechanoreceptors, chemoreceptors, and osmoreceptors (osmotic stimuli)
135
GI hormones
are secreted by endocrinocytes located in the mucosal epithelium of the stomach and small intestines
stomach secretes gastrin
small intestine secretes secretin, cholecystokinin (CCK), and gastric inhibitory peptide
136
gastrin
secreted in response to the presence of food
stimulates the secretion of gastric acid by the parietal cells of the stomach mucosa
released mainly by the enteroendocrine G cells
137
secretin
stimulates a watery secretion of bicarbonate by the pancreas
138
cholecystokinin (CCK)
stimulates the secretion of pancreatic enzymes and bile from the liver and release bile form the gallbladder
139
gastric inhibitory peptide
inhibits gastric secretion and slows gastric emptying and motility
140
mouth and accessory structures
the mouth, tongue and teeth begin mechanical digestion
saliva begins chemical digestion
141
saliva
98-99.5% water and remaining % is ions, glycoproteins, enzymes (amylase), growth factors, and waste products
142
lingual lipase
minor role in breaking down triglycerides
143
pharynx
runs from the nasal and oral cavities to the esophagus (for digestion) and to the larynx (for respiration)
during swallowing the soft palate rises to close off the nasopharynx, the larynx elevates, and the epiglottis fold over the glottis
144
sections of the esophagus
the upper esophageal sphincter -> protects against the reflux of food into the airways and prevents entry of air into the digestive tract
-> made of skeletal muscle
the lower esophageal sphincter -> protects the esophagus from the reflux of gastric contents -> made of smooth muscle
cells in the esophageal wall secrete mucus that eases the passage of the food bolus
145
stomach
participates in all digestive activities except ingestions and defecation
it vigorously churns good
secretes gastric juices that break down food and absorbs certain drugs, including aspirin and some alcohol
begins the digestion of proteins and continues the digestion of carbs and fats
stores food as an acidic liquid called chyme and releases it gradually into the small intestine through the pyloric sphincter
146
pyloric sphincter
the sphincter between the stomach and small intestines
147
parietal cells
located primarily in the middle region of the gastric glands
they are relatively large cells that produce HCl and intrinsic factor
148
HCl
is responsible for the high acidity (pH 1.5 to 3.5) of the stomach and is needed to activate the protein-digesting enzyme, pepsin that helps denature proteins
149
Intrinsic factor
necessary for the absorption of vitamin B12 in the small intestine
150
chief cells
they secrete pepsinogen, the inactive proenzyme from of pepsin
HCl is necessary for the conversion of pepsinogen to pepsin
150
enteroendocrine cells
secrete various hormone into the interstitial fluid of the lamina propria (the mucosa) -> gastrin
151
3 main regions of the small intestine
duodenum, jejunum, ileum
152
purpose of small intestine
where digestion is completed and virtually all absorption occurs
these activities are facilitated by structural adaptations that increase mucosal surface area
-> circular folds, villi, and microvilli
153
microvilli in small intestine
around 200 million per square mm of small intestine
they contain brush border enzymes that complete digestion or carbs and proteins
154
intestinal juices
combined with pancreatic juice, they provide the liquid medium that is needed to further digestion and absorb substances from chyme
155
main regions of the large intestine
cecum, colon (ascending, transverse, and descending), and rectum
156
purpose of the large intestine
absorbs water and forms feces
is responsible for defecation
157
bacterial flora in large intestine
break down additional carbohydrate residue and synthesize certain vitamins
158
mucosa of the large intestine
has a large amount of goblet cells that secrete mucus that eases the passage of feces
the entry of feces into the rectum activates the defecation reflex
159
accessory organs for the small intestine
chemical digestion in the small intestine is enhanced by :
- the liver -> produces bile and delivers it to the common hepatic duct (bile contains bile salts and phospholipids that emulsify large lipid globules into small lipid droplets)
- the gallbladder -> stores and concentrates bile, releasing it when it is needed by the small intestine
- the pancreas -> produces amylase, lipase, trypsin (activates chymotrypsin), and bicarbonate rich pancreatic juice and delivers it to the small intestine through ducts
160
pancreatic juice
buffers the acidic gastric juice in chyme, inactivates pepsin from the stomach, and secretes chymotrypsin and elastase
161
difference between male and female urinary structures
the urethra is the only urinary structure that is significantly different
the male urethra is longer than the female urethra
162
who has a higher chance of developing an UTI
females shorter urethra contributes to the higher incidence of UTIs
163
what is filtered to form urine
blood is filtered through the kidneys to form urine
164
what does the urinary system protect the body against
protects the body against the accumulation of waste products and excess substances in the bloodstream
maintains proper fluid balance and regulating electrolyte levels
165
pathway of the urethra
stemming from the bladder, the urethra transports urine to the outside of the body
166
trigone
the trigone is a triangular area in the urinary bladder formed by the two ureteral orifices and the internal urethral orifice
located at the base of the bladder (inside)
167
internal urinary sphincter
under involuntary control
made of smooth muscle
controls urination
168
external urinary sphincter
under voluntary control
made of skeletal muscle
controls urination
169
urethra
arises from the trigone area at the base of the bladder
170
prostatic urethra
the portion of the male urethra that travels through the prostate that is located just below the bladder
171
retroperitoneal
means that an organ is positioned behind the peritoneum (the lining of the abdominal cavity)
172
bladder
is largely retroperitoneal and can hold up to 500 - 600 nL urine
173
micturition
the process of voiding the urine and involves both involuntary and voluntary actions
aka urination
174
detrusor muscle
the wall of the bladder
comprised of smooth muscle fibres oriented in multiple different directions
it is not the only way to create enough force to void urine, the external urinary sphincter, pelvic floor muscles, and abdominal muscles all assist
175
voluntary control of micturition
requires a mature and intact sacral micturition centre
also requires an intact spinal cord
176
sacral micturition centre
an area of the spinal cord near the base, between S2 and S4
controls your bladder and internal sphincter
177
flap valve
the oblique angle that the ureters join the bladder creates a valve-like sphincter or flap valve
prevents urine from backing up into the ureters and kidneys
178
ureters
are not passive, they actively move urine through muscular contractions (peristalsis)
there are smooth muscles in the walls of the ureters -> thick muscular wall
are retroperitoneal
lead from the renal pelvis of the kidney to the trigone area of the bladder
179
what protects kidneys
they are protected by several layers or tissues and fat in the retroperitoneal space -> includes the renal fat pad, overlying ribs, and muscle
180
amount of cardiac output kidneys receive at rest
20 -25 % of the cardiac output from the heart
181
left kidney placement
located higher than the right kidney because it the right kidney is displaced by the liver -> the liver pushes it down
182
renal fat pad
aka adipose capsule
serves as a protective cushioning layer around the kidneys
provides insulation and protection against physical trauma
surrounds the kidneys in the retroperitoneal space
183
adrenal glands
found on top of the kidneys
they produce the hormones adrenaline, aldosterone, and cortisol
184
structure of kidney
divided into two regions
cortex (outer)
medulla (inner)
185
distribution of cardiac output to body
brain 15%
skin 5%
heart 5%
muscles 20%
kidneys 20-25%
liver 25%
other 10%
186
renal arteries
arise directly from the aorta
187
renal papillae
bundles of collecting ducts the transport urine to the calyces
187
renal vein
drain directly into the inferior vena cava
188
renal hilum
the renal artery, renal vein, and renal pelvis all enter or exit the kidney from the renal hilum
189
efferent arterioles
carry blood away from the glomerulus
blood that is not filtered into the nephron via the renal corpuscle, passes form the glomerulus to the efferent arteriole -> becomes the peritubular capillaries and then the vasa recta
goes around the nephron and drains into the renal vein
190
afferent arterioles
carry blood towards the glomerulus and supplies the nephrons with blood
branch off from the renal artery
191
nephrons
filter waste products and excess substances from blood to form urine
the basic structural and functional unit of the kidney
1,3 million per kidney
consists of the renal corpuscle, PCT, loop of Henle, and DCT
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glomerulus
is formed from a tuft of the afferent arteriole
filters blood and the filtrate is captured by Bowman's capsule
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renal corpuscle
formed by Bowmans capsule and the glomerulus
is the blood filtering component of the nephron
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Vasa recta
form the second capillary bed that surrounds the proximal and distal convolutes tubules and the loop of Henle
remove water and solute from the nephron
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reabsorption
occurs as the filtrate flows through the nephron
substances that the body needs is reabsorbed back into the blood -> glucose and water
begins in the proximal convoluted tubule which majority of the tubular reabsorption occurs, but also occurs through the length of the nephron
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secretion
a process in which substances move from the blood to the peritubular capillaries into the filtrate
allows for additional wastes and other materials to leave the body in the urine
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filtrate
is processed and gathered by collecting ducts that are connected to the distal convoluted tubules
the collecting ducts drain into the renal papilla which merge with the renal calyx -> the filtrate then moves from the calyx to the renal pelvis and then the ureters
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nephron in cortex
bowmans capsule
proximal convoluted tubule
distal convoluted tubule
parts of the collecting duct
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nephron in the medulla
the loop of Henle descends into the medulla in juxtamedullary nephrons
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juxtamedullary nephrons
nephrons that have long loops of Henle that extend deep into the medulla
15% of nephrons of juxtamedullary
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cortical nephrons
have short loops of Henle
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principle functions of the nephrons
filtration
reabsorption (back into the blood)
secretion (from the blood into the urine)
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renin
an enzyme made by special cells in your kidneys
part of the renin-angiotensin-aldosterone system -> designed to regulate your blood pressure
renin controls the production of aldosterone
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podocytes and their pedicels
are found in the lining of the Bowman's capsule
the pedicels extend from the podocytes and warp themselves around the capillaries of the glomerulus to form filtration slits
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fenestrated
small pores or opening
the glomerulus is fenestrated which allows for efficient filtration of blood plasma
allows for the passage of water, ions, and small molecules but prevents proteins and blood cells from passing
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mesangial cells
smooth muscle-like cells that contain actin and myosin
contraction of mesangial cells regulates the size of the capillary lumen and the amount of glomerular blood flow
they can also phagocytize trapped debris and protein within the glomerulus, prevents blockages
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filtration regulation
regulated by fenestration in capillary endothelial cells, podocytes with filtration slits, membrane charge, and the basement membrane between capillary cells
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juxtaglomerular apparatus (JGA)
is a microscopic structure located between the renal corpuscle and the returning DCT
maintains blood pressure and acts as a quality control mechanism to ensure proper glomerular flow rate and efficient sodium reabsorption
JGA cells produce the enzyme renin -> central role in blood pressure regulation
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Macula densa
the wall of the DCT that forms part of the JGA
are salt sensors that generate chemical signals in the JGA that control kidney functions
sense changes in sodium chloride levels and will tigger a response to increase of decreases reabsorption of ions and water in the blood
cluster of cuboidal cells
release paracrine signals
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blood osmolarity
when blood osmolarity goes up, filtration and urine formation decrease and water is reabsorbed and conserved
-> more ADH is secreted, less urine is secreted
When blood osmolarity goes down, filtration and urine formation increase and
water is excreted
-> less ADH is secreted, more urine is produced
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aldosterone
helps control the balance of water and salts in the kidneys, by keeping sodium in and releasing potassium from the body
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Glomerular filtration rate (GFR)
is influenced by hydrostatic pressure and colloid osmotic pressure
under normal circumstances -> hydrostatic pressure is significantly greater and filtration occurs
blood inside the glomerulus creates glomerular hydrostatic pressure which forces fluid out of the glomerulus into the glomerular capsule
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hydrostatic pressure of the glomerulus
depends on systemic blood pressure, auto regulatory mechanisms, the sympathetic nervous system, and paracrine hormone
the kidney can function under a wide range of blood pressures due to the auto regulatory nature of smooth muscle
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mechanisms of solute recovery
active transport
simple diffusion
facilitated diffusion
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formation of filtrate
most filtered substances are reabsorbed back into the bloodstream
urea, NH3, creatinine, and some drugs are filtered or secreted as wastes
H+ and HCO3- are secreted or reabsorbed as needed to maintain acid-base balance
water movement is primarily due to pressure
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PCT
proximal convoluted tubule
the most metabolically active part of the nephron
almost 100% of glucose, amino acids, and vitamins are recovered in the PCT
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descending loop of Henle
promotes the recovery of water due to high interstital osmolarity
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ascending loop of Henle
does not allow water to pass through, but actively recovers Na+, reducing filtrate osmolarity
90% of water is recovered before the forming urine reaches the DCT, which will recover another remaining 10%
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ANS of the kidneys
the kidneys are supplied with
sympathetic nerves (innervated) from the ANS
sympathetic nerves typically decreases blood flow to the kidney,increases renin production
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chemical reactions of life
take place in aqueous solutions
body is mostly water
balance of water and solute concentrations must be maintained to ensure cellular functions
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electrolyte
an mineral dissociated from a salt that carries an electrical charged (ions) is called an electrolyte
help stabilize enzyme structures and conduct electrical impulses along cell membranes
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hydrostatic pressure
the force exerted by a fluid against a wall, causes movement of fluid between compartments
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state of the cytosol
if the cytosol is too concentrated due to water loss, cell functions begin to deteriorate
if the cytosol becomes too dilute due to water intake, cell membranes can be damages and the cell can burst
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hypertonic
external environment has increased concentration of solutes and water will flow out of the cell
cell shrinks
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isotonic
no net movement of water into or out of the cell
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hypotonic
external environment has decreased concentration of solutes and water will flow into the cell
cell expands
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water intake
homeostasis requires that water intake and output be balanced
10% of water available to the body is generated at the end of aerobic respiration during cellular metabolism, the rest comes from food and liquid
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ADH
a hormone that helps the body to retain water by increasing reabsorption by the kidneys
released by the posterior pituitary gland
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plasma osmolality
the ratio of solutes to water in blood plasma
osmoreceptors are sensory receptors in the thirst centre in the hypothalamus that monitors osmolality -> stimulates the release of ADH
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aquaporin
are strongly expressed and functionally important is the kidneys, CNS, eyes, skin, and exocrine glands
purpose is to transport water across cell membranes in response to osmotic gradients created by active solute transport
pores the increase the flow of H2O
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electrolyte stimulation on hormones
electrolytes stimulate the release of aldosterone
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6 key electrolytes
Sodium -> major extracellular fluid cation
Potassium -> major intracellular fluid cation
Chloride
Bicarbonate -> buffer systems
Calcium
Phosphate
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Hyponatremia/ Hypernatremia
hyper = too much sodium and not enough fluid
causes -> dehydration, diarrhea, kidney disfunction, taking diuretics
hypo = too much fluid and not enough sodium
causes -> diuretics, vomiting, diarrhea, CHF, renal and liver disease
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hypokalemia/ hyperkalemia
hyper = too much potassium in your blood
causes -> high diet in potassium, kidney disease, drug use
hypo = low potassium levels in blood
causes -> alcohol uses, chronic kidney disease, excessive sweating, diarrhea
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Hypochloremia/ Hyperchloremia
hypo = reduced levels of chloride in blood
causes -> diarrhea, vomiting, kidney problems, excessive sweating, chronic respiratory acidosis
hyper = increased levels of chloride in blood
causes -> renal failure, diarrhea
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hypocalcemia/ hypercalcemia
hyper = increased levels of calcium in blood
causes -> excess parathyroid hormone produced
hypo - decreased levels of calcium in blood
causes -> vitamin D deficiency, hypoparathyroidism, renal disease
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Hypophosphatemia/ Hyperphosphatemia
hypo = decreased phosphate in blood
causes -> malnutrition, vitamin D deficiency, issues with electrolytes
hyper = increased phosphate in blood
causes -> advanced chronic kidney disease, hypoparathyroidism, metabolic and respiratory acidosis
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Angiotensin II and Aldosterone
control the exchange of sodium (reabsorbed) and potassium (excreted) between the renal filtrate and the renal collecting tubule
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PTH, calcitriol, and calcitonin
regulate calcium and phosphate
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ideal pH of the blood and body fluids
7.35 - 7.45
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buffers
a substance that prevents radical change in fluid pH by absorbing excess hydrogen or hydroxyl ions
buffers in the body include
- cell and plasma proteins
- hemoglobin
- phosphates (travels in weak acid or base forms)
- bicarbonate ions
- carbonic acid
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acid-base homeostasis
the respiratory and renal systems play major roles in acid-base homeostasis by removing CO2 and hydrogen ions, respectively
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bicarbonate buffer
the primary buffering system of the intracellular fluid surrounding the cells in tissues
(increases pH, more basic) carbon dioxide + water <-> carbonic acid <-> bicarbonate and hydrogen ion (decreases pH, more acidic)
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hemoglobin as a buffer
during the conversion of CO2 to bicarbonate, hydrogen ions liberated in the reaction are buffered by hemoglobin
