Bios 355 Exam 3 Flashcards
(158 cards)
1
Q
Systole
A
Contraction phase
2
Q
Diastole
A
Relaxation phase
3
Q
Cardiac cycle
A
- Both atria and ventricles are relaxed
- Blood return from venous system enters atria (AV valves between atria & ventricle are open, blood enters ventricle)
- Ventricles expand to accommodate the increase in volume of blood
- SA node initiates AP
- Blood is forced through the AV valves into the ventricles
- AP has progressed through the AV node down the Bundle of his and into Purkinje fibers
- Begin ventricular contraction
- Pressure continues to rise (isovolumetric contraction)
- Ventricular pressure exceeds arterial pressure
- AP is completed
- When ventricular pressure falls below arterial pressure semilunar valves close (2nd heart sound)
- Ventricle replaces isovolumetrically
- When the ventricle pressure falls below the atrial pressure the AV valves will open
4
Q
Collagen cords (cardiac tendinae)
A
Tether the valves
5
Q
End diastolic volume
A
Max volume in ventricles
6
Q
Vasculature (flow of blood through the system)
A
- Blood returns to heart via vena cava
- Through the tricuspid valve to the right ventricle
- Ventricle contracts and pushes blood
- Out of pulmonary circulation
- Coalesce into pulmonary vein
- Pulmonary vein delivery blood to left atria
- Heart contracts
- Aorta > systemic calculation, blood is subdivided to various organs/tissues
- Coalesce into systemic veins
7
Q
Lungs
A
Total volume: 5 L/min
% C.O.: 100%
Increase in physical activity: 16 L/min
8
Q
Brain
A
Total volume: 0.7 L/min
Weighted volume: 55mL/100g
% C.O.: 14%
Increase in physical activity: 0.7 L/min (no change)
9
Q
Heart
A
Total volume: 0.2 L/min
Weighted volume: 70mL/100g
% C.O.: 4%
Increase in physical activity: 0.6L/min
10
Q
GI tract
A
Total volume: 1.35L/min
Weighted volume: 100mL/100g
% C.O.: 27%
Increase in physical activity: 0.5L/min
11
Q
Kidneys
A
Total volume: 1L/min
Weighed volume: 40mL/100g
% C.O.: 20%
Increase in physical activity: 0.4L/min
12
Q
Skeletal muscle
A
Total volume: 1L/min
Weighed volume: 5mL/100g
% C.O.: 21%
Increase in physical activity: 12L/min
13
Q
Skin
A
Total volume: 0.25L/min
Weighed volume: 10mL/100g
% C.O.: 5%
Increase in physical activity: 1.5L/min
14
Q
Characteristics of fluid flow
A
- Pressure falls as a function of distance (pressure drops due to friction)
- Decrease size of container and the amount of fluid stays the same (pressure increases)
- Blood flows from regions of high to lower pressure
- Resistance opposes flow
15
Q
Parameters that influence resistance
A
- Length of the tube (increase length > increase resistance)
- Radius of the tube (decrease radius > increase resistance)
- Viscosity of the fluid (increase viscosity > increase resistance)
16
Q
Blood vessels
A
Lined with endothelial cells
Communicate with SM
Low resistance
17
Q
Arteries
A
Diameter of 4mm Thick walls 1mm Lots of SM Elastic tissue Fibrous tissue (prevents rupture, strength)
18
Q
Arterioles
A
Diameter of 30 micrometers
Walls: 6 micrometers
SM
Little elastic/fibrous tissue
19
Q
Capillaries
A
Diameter: 8-9 micrometers
Single layer of endothelial cells
20
Q
Venules
A
Diameter: 20-25 micrometers Fibrous tissue Veins Wall: 0.5 mm SM, fibrous and elastic tissue
21
Q
Blood distribution 1. Pulmonary circulation 2. Heart 3 systemic arteries 4. Systemic capillaries 5. Systemic veins
A
- 9%
- 7%
- 13%
- 7%
- 64%
22
Q
Mean pressure
A
Arteries: 90 mmHg Arterioles: 60 mmHg Capillaries: 25 mmHg Venules: 15 mmHg Veins: 0-10 mmHg
23
Q
Flow velocity Arteries Arterioles Capillaries Venules Veins
A
48 cm/s 15 cm/s 1 cm/s 4 cm/s 30 cm/s
24
Q
Vascular peripheral resistance
A
Overall resistance to blood flow through the system
25
Vasoconstriction
```
Decrease radius
Increase resistance
Decrease flow
1. NE
2. Serotonin release
3. Endothelin (paracrine)
```
26
Vasodilation
```
Increase radius
Decreases resistance
Increase flow
1. Epi
2. Nitric oxide
3. Adenosine
```
27
Metabolic rate (indicators of high metabolism)
```
High CO2
Low O2
Low pH
High potassium
(Increase radius, decrease resistance, increase flow)
```
28
Histamine
Local inflammatory molecule
Can cause vascular endothelial cells to contract
Increase in blood flow
Vasodilation
29
Vasoactive intestinal peptide
Increase blood during digestion
| Produce neurons of the enteric nervous system
30
Capillary exchange
1. Single endothelial layer
2. Gap between cells that allow fluid out
3. Fluid is pushed out of the capillary by the hydrostatic pressure
Fluid bathes cells
Diffusion and transcytosis
Bulk flow
31
Vascular SM
Regulating the radius of arterioles
| Controls blood flow to the capillaries
32
With histamine
```
Bigger gaps between endothelial cells
Decrease resistance to flow
More fluid exits along with proteins
Allows WBC to exit
Swelling
Swelling creates gaps (make it easier for immune cells to get to site of inflammation)
Swelling is beneficial at a local level
```
33
Cardiac shock
Heart failure
34
Hypovolumic shock
Blood volume is too low
| Blood loss due to hemorrhaging
35
Septic shock
Bacterial infection
| System wide inflammation
36
Anaphylactic shock
Immune cell over reaction
37
Miscellaneous agents that influence blood flow
1. Inflammation (immune response)
2. Malnutrition
3. Anemia (low RBC concentration)
38
Systemic circulation
Left side of heart contracts, pulls blood to periphery
| Vasodilate when O2 is low, CO2 is high, pH is low
39
Pulmonary circulation
Right side of heart contracts, pulls blood to lungs
Vasodilate (SM)
Bloods gains O2
Gets rid of CO2
40
Angeiogenesis
Growth of blood vessels
Vascularization of a tissue
Exercise promotes angiogenesis in skeletal muscle
Very active during growth and development
Wound healing
41
Pathologies
Like to promote angiogenesis in coronary heart tissue
| Like to prevent angiogenesis in cancer
42
Blood
5 liters in body
40% blood cells
60% fluid
43
Erythrocytes
RBC
| Gas transport
44
Leukocytes
WBC
Defense
Immune response
45
Platelets
Coagulation
Cell fragments
Contain mitochondria, ER, secretory vesicles
Respond to collagen
46
Proteins in blood
Albumins: transport/attach hydrophobic molecules
Globulins: antibodies
Fibrinogen: blood clotting
47
Hematocrit
% of RBC in whole blood
Males: 40-52%
Females: 38-48%
48
Blood cell production
Marrow of bones
RBC > half life of about 4 months
WBC > half life of les than a day (100 billion)
49
Multipotent progenitor cells
Uncommitted blood stem cell
| Lymphocyte stem cell (acquired immune cells, T-cells, B-cells, antibodies)
50
Uncommitted blood stem cell
Route 1: erythroblast > differentiate > mature RBC
Route 2: megakaryocyte > produce platelets
Route 3: inmate immune cells
51
RBC production
1. Production is regulated by the hormone erythropoietin (EPO)
2. EPO is produced by kidney
3. EPO target bone marrow (activate the uncommitted blood stem cells)
4. Produce erythroblasts (nucleated)
5. Nucleus condenses
6. Erythroblasts > reticulocyte
7. Reticulocytes exit bone marrow (enter circulation)
8. 24 hours to mature into adult RBC
(Last about 120 days)
9. Take on biconcave disk appearance
52
Reticulocytes
Immature
Migratory
Leave bone marrow and enter circulation
53
Biconcave disk
Flexible
Increases surface area (more surface area, greater diffusion rate)
Stackable (less adhesion)
54
Iron transport systems
Intestine
Fe binds to a protein called transferrin
Transferrin: deliver to bone marrow used in Hb synthesis
55
Thrombopoietin
In liver
| Megakaryocytes produce more platelets
56
Colony-stimulating factor/interleukins
Increase WBC production
57
Hematopoiesis
Blood cell production
58
RBC degradation
```
Damaged RBC are consumed by macrophages
Occurs in spleen/liver
Digest RBC
Bilirubin in the blood
Filtered by kidney > excreted in urine
```
59
Bilirubin
Incorporated into bile in liver
Excreted
Color feces
60
Jaundice
Decrease in bilirubin excretion
| Increase in bilirubin in blood
61
Anemia
```
RBC disorder
1. Blood loss
2. Hemolytic anemia
> cytoskeletal defects
> hemoglobin defects (sickle cell)
> parasitic infection
> autoimmune disease
> drugs
3. Decrease RBC production
> iron deficiency
> vitamin deficiency (folic acid, B-12)
> certain drugs
4. Kidney problems
> decrease EPO production
> decrease RBC
```
62
Polycythemia Vera
```
Overproduction of RBC
Stem cell dysfunction
Hematocrit 60-70%
> increase blood velocity
> increase flow resistance
> decrease O2 delivery
> increase pressure (strain on heart)
```
63
Secretory vesicles
Contain cytokines (growth-factors)
> stimulate growth to seal the ruptured area
Contain ATP (released into interstitial fluid)
> vasoconstrictor
> decrease blood flow
Serotonin
> vasoconstrictor
64
Coagulation
Platelets respond to collagen
Collagen wrapped around vessels
Collagen stimulates a receptor on platelets that cause vessels to fuse with PM
Release vasoconstrictor: cytokinesis
Platelets stick to collagen and begin forming a plug
Release thromboxane A2 (induces platelet sticking)
Induces blood clotting
65
Final stage
Thrombin (enzyme)
Fibrinogen into fibrin
X-link protein is factor 13 (XIII)
66
Prothrombinase
Factor X and thromboplastin
| Can convert prothrombin into thrombin
67
Antithrombrin III
Prevents clots
| Basophils > heparin (anticoagulant)
68
Thrombmodulin
Promote the breakdown of fibrin
| Plasmin > digest clots
69
Prostaglandins
Required for clot formation
70
Respiration
1. Ventilation of the lungs
2. Exchange of gas between the lungs and blood (gas in blood)
3. Transport of gas in the blood
4. Exchange of gases in the blood and the tissues (gas out of the blood)
71
Conducting system
1. Mouth and nose
2. Pharynx and larynx
3. Trachea (large pressure changes)
4. Primary bronchi (reinforced)
5. Secondary bronchi (semi-rigid)
6. Bronchioles (wrapped by SM)
> control air flow (regulation)
7. Terminal bronchioles
8. Alveoli (end sack) (gas exchange)
72
Pressure velocity
High at trachea/bronchi
| Low at bronchioles/alveoli
73
Alveoli
```
Single cell layer
Type I: very abundant
Very thin
Gas exchange
Type II: thicker
Secrete surfactants (detergent)
Not as abundant
```
74
Detergent
Decrease surface tension
Decrease cohesion
Prevents alveoli from sticking and collapsing
75
Gas laws
1. Total pressure of a mixture of gases is the sum pressures of the individual gases (Dalton's law)
2. Gases move from areas of high pressure to areas of low pressure
3. Boyle's law: P1V1 = P2V2
Ideal gas law: PV = nRT
76
Factors that influence the amount of the gas that can be dissolved in a fluid
1. Gas pressure (gradient) (regulate)
2. Gas solubility (constant)
3. Temperature (constant)
77
Process the air
1. Conducting system has very high surface area
2. Bring gas to body temperate (usually warming)
3. Bring gas to 100% humidity (saturated with water) > can't afford to dry out endothelial cells
4. Clean the gas > lining of conducting system produces mucus, has cilia that beat in one direction
Create a conveyer belt moving the mucus out of the lungs
78
Cystic fibrosis
Broken Cl channels
Lungs cannot produce fluid
Mucus gets too thick > cilia can't move
Mucus builds up in the lungs > decrease gas exchange > pulmonary infection
79
Lungs (alveoli)
Expand during inspiration (compliance)
| Return to resting volume during expiration (elasticity)
80
Emphysema
Destroys elastic fibers
| Lung is compliant but no recoil (difficult to exhale)
81
Fibrotic lung disease
Loss of compliance
| Difficult to inhale
82
Ventilation
Inspiration > air flow follows the changes in pressure
Rest: atmospheric pressure = intrapulmonary pressure (no air flow)
Muscles in thoracic cage contract > pull on the pleural membrane > force is transmitted to the pleural fluid > pulls on the alveoli
Rapture the pleural membrane > nothing pulling on lung tissue > due to elastic nature it collapses
Increase volume in lungs > decrease pressure in lungs
Atmospheric pressure is greater than the intrapulmonary pressure
83
Ventilation 2
Airflow from atmosphere > lungs > contraction stops > pressure equilibrates
84
Expiration
Lack of contraction
Relaxation is passive
Elasticity decreases lung volume > increases lung pressure
Lung intrapulmonary pressure is greater than atmospheric pressure
85
Regulate frequency and depth
Respiratory control center (medulla)
A. Dorsal respiratory group (DRG)
B. Ventral respiratory group (VRG)
86
Quiet respiration
DRG controls activity of the intercostal muscles and diaphragm (rhythmic increase in AP frequency) > stimulate skeletal muscle for inspiration
VRG is inactive
87
Force respiration
DRG AP increases in freq.
stimulates VRG
Increase force of inspiration
Stimulation of VRG provides forced expiration (internal intercostal muscles)
88
Control of respiratory center
```
1. Apneustic center (pons)
Stimulate DRG
2. Pneumotaxic center (pons)
Inhibits Apneustic center
These neurons receive sensory info > O2, CO2, pH
```
89
Increase activity of pneumotaxic center
Result will be short and shallow ventilation
90
Decrease activity of pneumotaxic center
Result will be slow deep ventilation
91
Physical and chemical stimuli in the lungs
```
Irritants
Temperature
Pain
Water
Trigger apnea protective reflexes
Coughing/sneezing
Reflex ability to stop respiration during swallowing/vomiting
```
92
Hering-Brewer reflex
Inflation reflex
Prevents over inflation during forced inhalation
Sensors send AP to both Apneustic center and DRG
AP to VRG > excitatory (promote exhalation)
Increase stretch > increase AP frequently in lungs
> make it increasingly difficult for the DRG to stimulate the muscles
93
Deflation reflex
Prevent over deflation during forced exhalation
| Sensors fire AP to the VRG > inhibitory synapse blocks the VRG > end exhalation
94
Lung volume capacity
TIDAL volume: normal volume of air exchanged per breath at rest (500 mL)
INSPIRATORY reserve: additional volume during forced inhalation (2500 mL)
EXPIRATORY reserve: additional volume during forced exhalation (1000 mL)
RESIDUAL volume: volume of air remaining in the lungs at the end of max forced exhalation (1000 mL)
VITAL capacity: max total volume that can be exchanged (4800 mL)
TOTAL LUNG capacity: vital capacity + residual volume (6000 mL)
DEAD SPACE: volume of gas residing in the conducting airways (no gas exchange)
Tidal volume must exceed dead space
95
Chemoreceptors
CO2 + H2O ↔️ H + HCO3
| Increase CO2 > increase H (decrease pH)
96
Bronchiole tubes (air flow)
Increase CO2: dilate
Decrease CO2: constrict
Increase O2: constrict
Decrease O2: dilate
97
Pulmonary arterioles (blood flow in lungs)
Increase CO2: constrict
Decrease CO2: dilate
Increase O2: dilate
Decrease O2: constrict
98
Systemic arterioles
| Blood flow periphery
Increase CO2: dilate
Decrease CO2: constrict
Increase O2: constrict
Decrease O2: dilate
99
Chemoreceptors
1. CO2/pH sensors
2. O2
HO-2 heme oxygenase
100
Heme oxygenase
```
Decrease O2
Produces CO
Activates qua cyclase
GTP > cGMP
cGMP > inhibits K channel
> depolarize
> activate v-gated Ca channel (increase Ca influx, release NT)
Fire AP to the respiration control center
```
101
Hypoxia-inducible factor
HIF alpha
HIF beta
Both dimer (transcription factor)
Hypoxia stimulate growth of blood vessels
Up regulation of glycolytic enzymes
Stimulate EPO production/increase RBC production
102
Regulation of respiration
Primary signal is pH (99.99%)
103
Gas exchange
1. Rate of diffusion for a gas is directly proportional to partial pressure concentration gradient
2. " " directly proportional to the available surface area
3. " " directly proportional to distance
104
Total gas pressure
Sea level: 760 mmHg
Atmosphere: 593 mmHg nitrogen
160 mmHg oxygen
0.25 mmHg CO2
105
O2 transport in blood
Free dissolved O2 (2% total) (usable fraction)
98% of the O2 is carried bound to the Hb inside the RBC
O2 diffuse from the alveoli to the interstitial fluid
O2 diffuse from interstitial fluid to the blood inside the capillary
O2 diffuse from the capillary to inside the RBC (bind to Hb)
Hb is an oxygen buffer (binds O2 when the O2 is high, releases O2 when the O2 is low)
106
Hemoglobin
4 subunits (centered around an iron)
4 O2 binding sites
Fetal/adult
107
Factors that influence O2 binding to Hb
1. Concentration gradient
2. pH (Bohr Effect)
Decrease pH > decrease Hb affinity for O2
Increase pH > increase " "
3. Temperature
Decrease temp > increase " "
Increase temp > decrease " "
4. Organo-phosphates (glycolytic byproducts)
2,3-diphosphoglycerate
Increase 2,3-DPG > decrease Hb affinity for O2
108
How does an active tissue induce Hb to release O2?
1. Active cell produce a lot of CO2
CO2 + H2O <> H2CO3 <> H + HCO3 (increase CO2 > decrease pH)
2. Decrease pH will cause a decrease in Hb affinity for O2 > release O2 (Bohr effect)
109
Bohr Effect
Cells that produce high CO2 levels also consume high levels of O2
CO2/pH as a proxy for O2 demand
110
Transport of CO2
1. Free dissolved CO2 (7%)
2. Conversion of CO2 > HCO3
CO2 + H2O <> H2CO3 <> H + HCO3 (70%)
3. Carbamino linkages
CO2 binding to amine groups > only when the pH decreases
Increase CO2 > decrease pH > induces carbamino linkages
Cl/HCO3 exchanger (band 3 protein) maintains gradient for CO2 diffusion into RBC
Cl maintains electrical neutrality
111
Unloading of CO2 at lungs
1. Alveoli PCO2 is lower than pulmonary blood PCO2 (diffusion of CO2 from blood to alveoli)
2. CO2 + H2O <> H2CO3 <> H + HCO3 (decrease CO2)
Converting all the HCO3 back to CO2
CO2 is free to diffuse toward alveoli
Cl shifts in opposite direction as CO2 decreases and pH increases > cause the carbamino linkages to break > release CO2
Hb gains affinity for O2 > Hb binds O2
112
Pulmonary
Increase pH (decrease CO2)
O2 binds
CO2 is released
113
Systemic
Increase CO2 (decrease pH)
Release O2
Bind CO2
114
Ventilation
Maintain PCO2 at the alveoli
pH drives ventilation
Increase activity > increase CO2 production, decrease pH
Respiratory sensors cause ventilation to increase
115
Hyperventilation
Increase alveoli ventilation above and beyond requirements
Decrease PCO2 beyond normal level
pH increase higher than normal
pH influences Hb O2 binding affinity
Hb binds O2 with greater affinity
Increase in pH Hb does not release O2 (start starving tissue of O2, CNS stutters due to drop in ATP)
116
Hyperventilation summed up
```
Decrease lung PCO2 (too far)
Decrease blood PCO2 (too far)
Increase blood pH (too far)
Increase Hb affinity for O2 too much (can't let go)
Decrease O2 delivery to tissues
```
117
Metabolic acidosis
Respiratory compensation
Decrease PCO2 lower
pH increases
118
Metabolic alkalosis
Vomiting (loss of acid)
Body fluids pH increases
Respiratory compensation: decrease ventilation, increase PCO2, pH decreases
119
Asthma
```
Hypersensitive bronchiole SM
Over constricts
Increase air flow resistance
Decrease ventilation in lungs
Inflammatory signals, histamines, leukotrienes, Ach cause bronchiole SM to constrict
```
120
Treatment for asthma
Anti histamine
Beta-adrenergic receptor agonists (sympathetic) cause relaxation
Inhalers
Blockers of leukotrienes production
Steroids (anti inflammatory)
Active transcription factors
Produce a protein that blocks phospholipase A2 > makes substrate for leukotriene production
121
Renal physiology
1. Regulate extra cellular fluid volume
2. Regulate osmolarity
Increase osmolarity > decrease water conc. (Eat a big of potato chips: increase osmolarity, drink water: decrease osmolarity)
3. Regulation of ion conc. (Na, K(influence on voltage) Cl, Ca
4. Regulate pH (pH changes protein structure)
Excrete excess protons
Conserve protons (add or subtract H protons)
5. Excretion of waste (or anything foreign)
Urea (nitrogenous waste)
Bilirubin (heme breakdown from RBC)
Creatinine (breakdown of creatine)
6. Sensory (endocrine gland)
EPO production
Hormones for Ca homeostasis
122
Deamination
```
Releases ammonia (NH3)
Very toxic (liver)
Convert NH3 into urea
Urea is less toxic
```
123
Uric acid
By product of purine breakdown
Much less soluble
Birds/reptiles > Uric excretion
Uric acid precipitates on shell during development
124
Renal fascia
Collagen fibers that extend from renal capsule and anchor to the peritoneum
125
Nephrons
Functional unit of kidney
126
Glomerulus
Filtration
Fluid out
Modified capillary
127
Peritubular capillary
Reabsorption occurs
Fluid back in
Coalesce > renal vein > exist kidney
128
Bowman's capsule
Surrounds glomerulus and is the collection point for the filtrate
Filtrate is essentially blood minus RBC, WBC, platelets, and big proteins
180 liters/day
Recreate entire fluid phase of blood 60 times a day
129
Proximal tubule
Nutrient reabsorption
| End of proximal tubule: 54 liters/day
130
Loop of Henle
```
Create an osmotic gradient (induces osmosis)
Promotes retention of water
End of loop: 18 liters/day
99% of blood is in the cortex
1% of blood flow to the medulla
```
131
Distal tubule
Fine tune urine conc.
K
pH
Ca
132
Collecting duct
Regulated water permeability
Control the amount of water reabsorbed
Uses gradient created by the loop of Henle
1.5 liters/day (becomes urine)
133
Kidney process
1. Filtration
2. Reabsorption (from urine to blood)
3. Secretion (from blood to urine)
4. Excretion (urination aka micturition)
134
Filtration route
1. In plasma
2. Cross the endothelium of the glomerulary capillary
3. Cross basement membrane (connective tissue)
4. Epithelia of Bowman's capsule (enters lumen of capsule)
135
Bowman's Capsule epithelia
Prodocyte (foot)
| Wrap around the capillary
136
Slits
Gaps between the podocytes
Dictate filtration resistance
Increase size of slits > decrease resistance > more filtrate
137
Mesangial cells
Contractile
Pull on podocytes
Regulate the slit size and resistance
Phagocytitic >consume clogged debris that gathers in the slits (keep filter clean)
138
Force driving filtration at the glomerulus
Blood pressure: 50 mmHg + (favors filtration)
Bowman's capsule: 15 mmHg - (works against filtration)
Osmotic pressure gradient: 25 mmHg -
Total net pressure: 10 mmHg +
139
Glomerular filtration rate
1. Net filtration pressure
2. Slit resistance
3. Surface area (how much is available)
Average GFR is 125 mL/min
140
Renal blood flow
Increase flow rate through the glomerulus (no change in blood pressure)
Blood pressure stays at 50 mmHg
Bowman's capsule stays at 15 mmHg
Increase flow rate > less change in OP > Change in pressure decreases > net pressure increases
141
Constrict afferent arteriole
Decrease blood pressure at glomerulus
Decrease flow rate
Decrease GFR
142
Dilate afferent arteriole
Increase blood pressure at glomerulus
Increase flow rate
Increase GFR
143
Dilate both afferent and efferent arterioles
```
No change in blood pressure
Increase flow (decrease OP)
Increase GFR
```
144
Regulatory routes
1. Auto regulation (myogenic, SM)
2. Auto regulation (tubulo glomerular) flow rate of a fluid through the nephron
3. Hormonal
4. Autonomic nerves
145
Myogenic auto regulation
Maintain GFR despite changes in local blood pressure/flow
Reflex changes by the vascular SM
Endothelial cells produce paracrine signals
A. Constrict (decrease pressure/flow)
B. Dilate (increase pressure/flow)
146
Tubuloglomerular auto-regulation
Regulating GFR based on rate of flow through the nephron flow is too fast
Autonomically decrease GFR to slow down the rate the filtrate is entering the nephron
Giving the nephron time to reabsorb all the essential nutrients
Flow is measured by distal tubule
147
Regulation of GFR
1. Myogenic auto regulation
2. Tubularglomerular auto regulation
Based on flow rate of fluid through the nephron
Sensor is the macula densa cells of the distal tubule
148
Example of regulation of GFR
1. Increase GFR
2. Increase flow rate through the nephrons
3. Increase flow at macula densa
4. Distal tubule reabsorbs Na
> increase flow > increase Na availability > increase Na transport > cause a voltage change at the macula densa (signal)
5. Cause the release of a paracrine vasoconstrictor
6. Afferent arteriole constricts
> increase flow resistance > decrease glomerular pressure > decrease flow to the glomerulus
7. Decrease GFR
149
Autonomic regulation
1. Both afferent/efferent arterioles are innervate by sympathetic neurons > release NE > SM - alpha adrenergic receptors
2. Activation of receptor causes vasoconstriction
Decrease blood pressure > decrease flow > decrease GFR
150
GFR issues
```
Endurance athletes
Chronic vasoconstriction at glomerulus
Wastes accumulate
Low O2 at kidneys
Glomerular damage
```
151
Liver damage
Decrease plasma protein
Decrease blood OP
Unusually high GFR
152
Reabsorption at proximal tubules
Excrete 1.5 liters per day
Reabsorb 178.5 liters per day
Anything not selected remains in the nephron and becomes urine (urea, bilirubin, Uric acid, anything not recognized)
153
Transcytosis
Small proteins can fit through the glomerular slits and enter Bowman's capsule
P.T. Cells can bind proteins and encapsulate into endocytosis vesicles
154
Renal physiology
P.T. > reabsorption > Na linked nutrient transport > transcytosis > water by osmosis
155
Clearance
The ability of the kidneys to clean or clear the plasma (blood) of a certain substance
Clearance of Uric acid should be very high
Clearance of glucose should be very low
156
Inulin
Modified sugar
Filtered but no reabsorption
Clearance of inulin = GFR
157
PAH (para amino huyperic acid)
Filtered and totally secreted
No reabsorption
Clearance of PAH = total renal blood flow
If clearance exceeds GFR > substance is secreted
If clearance is less than GFR > substance is reabsorbed
158
Holding your breath
Increase PCO2
| Decrease pH > stimulates ventilation
