Set 7 (Part I) Flashcards
1
Q
What detects a decrease in blood volume and blood pressure?
A
- Volume receptors in the atria
- Carotid and aortic baroreceptors
2
Q
How does a decrease in blood pressure affect the cardiovascular system?
A
- Increase in cardiac output
- Vasoconstriction (vagus nerve, epinephrine)
- Increase in BP
3
Q
How does a decrease in blood pressure affect behaviour?
A
- Thirst causes increased water intake
- ECF and ICF volume increases
- Increase in BP
4
Q
How does a decrease in blood pressure affect the kidneys?
A
- Conserve H2O to minimize further volume loss
- ADH (reabsorption of water in tubules)
5
Q
When would a decrease in blood volume or blood pressure occur?
A
Major bleeding or extreme dehydration
6
Q
How does an increase in blood pressure affect the cardiovascular system?
A
- Decrease in cardiac output
- Vasodilation
- Decrease blood pressure
7
Q
How does an increase in blood pressure affect the kidneys?
A
- Excrete salts and water in urine
- Decrease in ECF and ICF volume
- Decrease blood pressure
8
Q
Describe the process of blood transportation to the kidneys.
A
- Renal artery brings blood to the kidneys
- After filtration through the kidneys (20% of blood), the fluid leaves through the renal vein
- The rest of the blood enters the capillary system that surrounds the tubules of the kidney
9
Q
How are the kidneys connected to the bladder?
A
Ureters
10
Q
How are the contents of the bladder emptied?
A
Through the urethra
11
Q
How much water can the bladder contain?
A
2 cups
12
Q
How does caffeine and alcohol affect the urine output?
A
- They are diuretics, so they increase urine output
- Thirst mechanism increases as well
13
Q
What are the functional units of the kidneys?
A
Nephrons
14
Q
What is the calyx?
A
- Also called the renal pelvis
- Collecting ducts from individual filtering units
- Empty into the ureter
15
Q
What are the differences between the male and female urethra?
A
- Urethra passes through the prostate in males
- Urethra is much longer in males
16
Q
What causes men to urinate more slowly and frequently as they age?
A
- Prostate gland enlarges due to andropose
- Prostate squeezes on the urethra, which decreases in diameter
17
Q
What consequences does a shorter urethra cause in women?
A
More prone to bladder infections
18
Q
How many nephrons are there in the kidney?
A
A million
19
Q
What sits in the renal cortex?
A
- Bowman’s capsule
- Proximal and distal tubules
- Start of the collecting duct
20
Q
What sits in the renal medulla?
A
Loop of Henle
21
Q
What are the two components of a nephron?
A
- Vascular component
- Tubular component
22
Q
Where does the blood that is not filtered by the glomerulus travel to?
A
- Efferent arteriole, which breaks down into capillaries
- Serve in ongoing absorption and excretion through the tubules
23
Q
How may substances be excreted if they are not filtered through the glomerulus?
A
Via the capillary network that surrounds the tubule
24
Q
What are the two distinct regions within the nephrons of the kidney?
A
- Renal cortex
- Renal medulla
25
Where is the dominant portion of the vascular component?
- The glomerulus
| - Tight ball of capillaries located within the Bowman's capsule
26
What is the filtered fluid of the glomerulus like? What does it become as it passes through the tubules?
- The filtered fluid is like plasma
| - Becomes filtrate as it passes through the tubules
27
How does the diameter of the afferent arteriole compare to the efferent arteriole?
- Afferent arteriole has a wider diameter than the efferent arteriole
- High hydrostatic pressure, which promotes filtration through the glomerulus
28
Describe the vascular route through the nephron.
- Afferent arteriole
- Glomerulus
- Efferent arteriole
- Peritubular capillaries
- Venules
- Renal vein
29
What are peritubular capillaries?
- Surround the tubular part of the nephron
| - Supply the blood for the exchange with the fluid in the tubular lumen
30
What is the structure of the Bowman's capsule membrane?
- Double epithelial cell-layered structure
- Single layer of epithelial cell (capillary lumen)
- Podocytes are fused to the endothelial cells that make up the glomerulus (lumen of Bowman's capsule)
31
What structure of the nephron creates an osmotic gradient?
The loop of Henle in the renal medulla
32
What occurs at the descending limb of Henle?
- Permeable to water (water moves out)
| - Not permeable to salt
33
What occurs at the ascending limb of Henle?
- Thicker epithelium
- Not permeable to water
- Permeable to salt (salt moves out)
34
What controls the concentration of urine? What hormone acts on that region?
- Distal tubule
| - ADH, aldosterone
35
What is the juxtaglomerular apparatus?
The ascending limb of Henle passes through a fork created by the afferent and efferent arteriole
36
Is glomerular filtration discriminant? What does it let pass through?
- Non-discriminant
| - Blood cells and plasma proteins are not filtered
37
What occurs to 20% of the plasma that enters the glomerulus? What occurs to 80% of the plasma?
- 20% of the plasma that enters the glomerulus is filtered
| - 80% of the plasma that enters the glomerulus is not filtered and leaves through the efferent arteriole
38
What are RBCs and WBCs or damaged tubular cells in a urine sample a sign of?
- Problem with the kidneys
| - Infection: largely WBCs and some RBCs
39
Why would you see WBCs and some RBCs in urine during an infection?
- Inflammation makes cell leaky
| - If the cells that are filtering in the glomerulus are leaky, they might let WBCs and RBCs pass through
40
What is tubular reabsorption? Is it selective?
- Highly selective
| - Movement of filtered substances from the tubular lumen into the peritubular capillaries
41
What is tubular secretion? Is it selective?
- Selective movement of non-tubular filtered substances
| - From the peritubular capillaries into the tubular lumen (for excretion)
42
Urine results from which three basic renal processes?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
43
What is the important statement to remember?
Anything filtered or secreted but not absorbed is excreted
44
To be filtered, a substance must pass through what?
1. The pores between the endothelial cells of the glomerular capillary
2. Acellular basement membrane
3. Filtration slits between the foot processes of the podocytes of the inner layer of Bowman's capsule
45
What is the effect of glomerular capillary blood pressure? Why?
- Favours filtration
- Afferent arteriole is much wider than efferent arteriole
- Blood is rushing through the complex at a HIGH pressure
- Hydrostatic force
46
Fluid moves from ____ pressure to ____ pressure in the glomerulus.
high
| low
47
What is the effect of plasma-colloid osmotic pressure?
Opposes filtration
48
What causes the plasma-colloid osmotic pressure?
- Larger plasma proteins cannot be filtered across the glomerulus membrane and enter Bowman's capsule
- They exert a colloid osmotic pressure on the filtered fluid in the Bowman's capsule
49
What is the effect of Bowman's capsule hydrostatic pressure?
Opposes filtration
50
What causes Bowman's capsule hydrostatic pressure?
Fluid pressure in Bowman's capsule opposes filtration
51
Which pressure may increase in the case of a blockage, such as kidney stones?
- Bowman's capsule hydrostatic pressure
| - Causes inflammation, pain, and damages the kidney
52
What are the three forces involved in filtration?
- Glomerular capillary blood pressure
- Plasma-colloid osmotic pressure
- Bowman's capsule hydrostatic pressure
53
How does the concentration of urine change from the cortex to the medulla of the descending loop of Henle?
Concentration increases
54
What is the urine concentration in the thick ascending limb?
- Removal of solute
| - Creates hyposmotic fluid
55
What states would influence reabsorption by the distal tubule?
- Dehydration: concentrated urine (more reabsorbed)
| - High blood pressure: dilute urine (less reabsorbed)
56
What is absorbed in the proximal tubule? Is it passive or active transport?
- HCO3- (passive)
- NaCl (active)
- H2O (passive)
- Nutrients (active)
- K+ (passive)
57
What is secreted in the proximal tubule?
- H+ (active)
| - NH3 (passive)
58
What is absorbed in the descending loop of Henle?
H2O (passive)
59
What is absorbed in the thin segment of the ascending limb of Henle? Is it active or passive?
- NaCl (passive)
| - Inner medulla
60
What is absorbed in the thick segment of the ascending limb of Henle? Is it active or passive?
- NaCl (active)
| - Outer medulla
61
What is absorbed in the distal tubule? Is it passive or active transport?
- NaCl (active)
- H2O (passive)
- HCO3 (active)
62
What is secreted in the distal tubule? Is it passive or active transport?
- K+ (active)
| - H+ (active)
63
What is absorbed in the outer medulla of the distal tubule?
NaCl (active)
64
What is absorbed in the inner medulla of the collecting duct?
- Urea (passive)
| - H2O (passive)
65
What allows for the absorption of water in the collecting duct? What does that contribute to?
- Absorption of urea
- Contributes to the hyperosmolarity found in the medulla
- Important in the countercurrent mechanism of exchange
66
Where is the highest osmolarity found in the nephron?
- In the inner medulla
| - Loop of Henle and collecting duct
67
As a result of NaCl movement out of the tubule into the medullary, what does the interstitial fluid become?
Hypertonic
68
How does the histology of the ascending limb differ from the descending limb?
Ascending limb is much thicker and limits the diffusion of most molecules
69
What occurs in terms of osmolarity of urine at the distal tubule?
Osmolarity decreases as NaCl has diffused into the interstitial fluid
70
What is the structure that makes concentrated urine? What structure maintains the osmotic gradient?
- Collecting duct: makes concentrated urine
| - Loop of Henle: maintains osmotic gradient
71
The water permeability of the _________ is adjustable.
collecting duct
72
How is the permeability of the collecting duct adjusted?
Adding or removing aquaporins
73
Describe how vasopressin causes insertion of water pores into the apical membrane of the collecting duct.
1. Vasopressin binds to membrane receptor
2. cAMP second messenger
3. Insertion of water pores into the apical membrane (storage vesicles)
74
How does the osmolarity of the medullary interstitial fluid compare to the osmolarity of the vasa recta? What does that cause?
- Osmolarity of the medullary interstitial fluid is lower than the osmolarity of the vasa recta
- Pulls water into the blood by osmosis
75
How does high osmolarity cause vasopressin release?
- Signals hypothalamic osmoreceptors
- Interneurons to hypothalamus
- Hypothalamic neurons synthesize vasopressin and is released from the posterior pituitary
76
How does decreased atrial stretch due to low blood volume cause vasopressin release?
- Atrial stretch receptor
- Sensory neuron to hypothalamus
- Hypothalamic neurons synthesize vasopressin and is released from the posterior pituitary
77
How does decreased blood pressure due to low blood volume cause vasopressin release?
- Carotid and aortic baroreceptors
- Sensory neuron to hypothalamus
- Hypothalamic neurons synthesize vasopressin and is released from the posterior pituitary
78
How does plasma osmolarity affect vasopressin release?
As plasma osmolarity increases, the levels of vasopressin secreted does as well
79
What two factors can affect filtration in the kidney?
1) Myogenic regulation
| 2) Tubuloglomerular feedback
80
How does myogenic regulation respond to an increase in arterial pressure?
1) Renal afferent arteriole is stretched
| 2) Vascular smooth muscle responds by CONTRACTING (increases resistance)
81
What is the function of the myogenic regulation?
The kidney does not want an increase of blood from an increase in arterial pressure, so it contracts to increase resistance
82
Which tubule is the juxtaglomerular apparatus located?
Distal tubule
83
What kind of cells are at the fork of the juxtaglomerular apparatus? What are they called in the wall of the afferent arteriole?
- Smooth muscle cells
| - Afferent arteriole: granular cells
84
What is the function of the macula densa in the juxtaglomerular apparatus?
Cells that act to detect changes in salt level in the fluid passing by them
85
What does the macula densa do in response to a larger quantity of fluid passing through the tubule?
- More salt is detected
| - Causes the macula densa to release adenosine
86
What does adenosine do?
- Acts as a paracrine regulator causing vasoconstriction at adjacent granular cells (afferent arteriole)
- Resistance increases
- Hydrostatic pressure in glomerulus decreases
- Glomerular filtration rate decreases
87
What part of the nephron forms the juxtaglomerular apparatus?
A) Bowman's capsule
B) Where the collecting duct joins the ureter
C) Where the ascending limb of Henle joins the distal tubule
D) Where the proximal tubule joins the descending limb
E) Where the descending limb joins the ascending limb
C) Where the ascending limb of Henle joins the distal tubule
88
What happens to the glomerular filtration rate when the afferent arteriole dilates?
A) Increases
B) Decreases
C) Stays the same
A) Increases
89
```
The plasma is most similar in chemical composition to the fluid in the _______.
A) Proximal tubule
B) Collecting duct
C) Distal tubule
D) Bowman's capsule
E) Ascending limb of the loop of Henle
```
D) Bowman's capsule
90
```
"Secretion" in a nephron always refers to transport of
A) Water into the nephron lumen
B) Water out of the nephron lumen
C) A solute into the nephron lumen
D) A solute out of the nephron lumen
```
C) A solute into the nephron lumen
91
```
After drinking a large volume of water, compensation is primarily achieved by a decrease in the level of the hormone
A) Aquaporin
B) Aldosterone
C) Vasopressin
D) Atrial natriuretic peptide
```
C) Vasopressin
92
Aldosterone secretion will be _______ by an increase in plasma potassium.
A) increased
B) decreased
C) not changed
A) increased
93
```
An 83–year–old woman with severe orthostatic hypotension is given Florinef, a potent aldosterone agonist. In addition to following her blood pressure, what parameter should also be monitored?
A) Heart rate
B) Serum potassium
C) Serum sodium
D) Serum chloride
E) Serum bicarbonate
```
B) Serum potassium
94
```
The hormone that most directly influences Na + balance in the body is
A) Vasopressin
B) Angiotensin
C) Renin
D) Aldosterone
E) Atrial natriuretic peptide
```
D) Aldosterone
95
```
Eating salty dry food without drinking will cause (before any response) a(n) ________ in body fluid osmolarity and ________ in the volume of the body fluids.
A) Decrease; no change
B) Decrease; an increase
C) Decrease; a decrease
D) Increase; no change
E) Increase; an increase
```
D) Increase; no change
96
The vasa recta are the _______.
A) peritubular capillaries associated with the loop of Henle
B) Osmoreceptors in the hypothalamus
C) Kidney cells that produce renin
D) Liver cells that produce angiotensinogen
A) peritubular capillaries associated with the loop of Henle
97
Where are mesangial cells found?
Between and around the glomerular capillaries
98
What is the function of mesangial cells?
They possess actin-like filaments that enable them to contact and alter blood flow through capillaries
99
What are granular cells?
Mechanoreceptors that secrete renin in response to a decrease in BP in the afferent arteriole
100
What are macula densa cells?
Chemoreceptors that monitor NaCl content going into the distal tubule, altering their absorption
101
Define the glomerular filtration rate.
The volume of fluid that filters into the Bowman's capsule per unit of time
102
What three hormones act to increase blood pressure?
- Vasopressin
- Angiotensin II
- Aldosterone
103
What hormone acts to decrease blood pressure?
Atrial natriuretic peptide
104
What is myogenic regulation?
Intrinsic ability of vascular smooth muscle to respond to pressure changes
105
What is the myogenic response in response to stretch in the afferent arteriole?
Vascular smooth muscle CONTRACTS
106
What is the tubuloglomerular feedback?
Paracrine signaling mechanism through which changes in fluid flowing through the loop of Henle influence GFR
107
What is the tubuloglomerular feedback in response to an increase in GFR?
1) Flow through tubule increases
2) Flow past macula densa cells increase
3) Paracrine signal (adenosine) from macula densa cells to afferent arteriole
4) Afferent arteriole constricts
5) GFR decreases
108
Is the osmolarity of the collecting duct cell lower or higher than the osmolarity of the vasa recta? What makes you say that?
- Osmolarity is higher in the vasa recta
| - Because water moves from the cell to the vasa recta by osmosis
109
People who inherit vasopressin V2 receptor deficiency will have urine that is dilute or concentrated?
Dilute because there is less water reabsorption
110
Why is less urine produced overnight than during the day?
- Vasopressin secretion shows a circadian rhythm
| - Increased secretion (increased absorption of water) overnight
111
Would vasopressin secretion be increased or decreased with dehydration?
Increased
112
What would occur if there was no high osmolarity in the medullary interstitium?
There would be no concentration gradient for osmotic movement of water out of the collecting duct
113
If a nephron has a shorter loop of Henle (does not dip as deep into the medulla), how would the concentration at the tip of the loop compare to a regular loop?
The concentration would be lower
114
What is the net result of the countercurrent multiplier in the kidney? What does it produce? What is hyperosmotic and what is hypoosmotic?
- Hyperosmotic interstitial fluid in the medulla
| - Hypoosmotic filtrate leaving the loop of Henle
115
Why doesn't the water leaving the descending limb of Henle dilute the interstitial fluid of the medulla?
- Because the capillaries of the vasa recta remove the water
| - Plays an important role in keeping the medullary solute concentration high
116
What hormone controls sodium balance?
Aldosterone
117
If a person experiences hyperkalemia, what happens to resting membrane potential and the excitability of neurons and the myocardium?
- Resting membrane potential depolarizes
| - Excitable tissues fire one action potential but are unable to repolarize to fire a second one
118
What controls physiological aldosterone secretion from the adrenal cortex? (2)
- Increased extracellular potassium concentration
| - Decreased blood pressure
119
What do sympathetic neurons stimulate in response to decreased blood pressure?
Stimulate granular cells to secrete renin
120
When fluid flow in the distal tubule decreases, what do macula densa cells signal granular cells to do?
Secrete renin
121
What are the effects of angiotensin II?
- Increases vasopressin
- Stimulates thirst
- Systemic vasoconstrictor
- Increases sympathetic output to the heart
- Increases proximal tubule Na+ reabsorption (aldosterone)
122
How does decreased blood flow in the renal arteries cause elevated renin levels?
- Decreases pressure in the afferent arteriole
- Decreases GFR
- Both events stimulate renin release
123
Why is it more efficient to put ACE in the pulmonary vasculature than in the systemic vasculature?
All blood passes through the pulmonary blood vessels with each circuit
124
What are the actions of ANP at afferent arterioles?
- Vasodilation to increase GFR
| - Inhibits renin secretion
125
What are the actions of ANP in the nephron?
Decrease Na+ and water reabsorption
126
What hormones does ANP influence?
Inhibits renin, aldosterone, and vasopressin secretion
127
What are the effects of hypokalemia?
- More difficult for hyperpolarized neurons and muscles to fire action potentials
- Failure of respiratory muscles and the heart
128
Glucose is found in the filtrate and not in the urine.
A) True
B) False
A) True
