Regulation of water and Na+ balance, ECF volume, and blood pressure

32 cards

5/3/10 9:00 AM


 
  
Created May 5, 2010
by
laurnb22

 

 
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1
What is the basic principle of body water balance?
 
Intake must be equal to output.
2
Where is ADH released from?
 
The posterior pituitary gland.  it is stored in secretory granules in nerve endings in...
3
Where are the cell bodies of the nerves that contain ADH located?
 
In the hypothalamus.
4
What causes the release of ADH?
 
Depolarization of the nerve terminals, which causes an increase in Ca2+ influx into the terminal,...
5
What are the 2 main stimuli of ADH release?
 
An increase in plasma osmolality (more important)Decrease in ECF volume
6
Increased plasma osmolality causes what 2 events?
 
1. ADH release2. Thirst
7
Large loss of ECF leads to what 2 events?
 
1. ADH release2. Thirst
8
T/F.  Large loss of ECF does NOT cause ADH release and thirst if the plasma osmolality...
 
FALSE.  Even if the plasma osmolality is low, a large loss of ECF will cause ADH release...
9
What is another name for ADH?
 
Vasopressin, or arginine vasopressin
10
Why is ADH also called vasopressin?
 
Because when it is released in response to a large decrease in ECF volume, it also acts as...
11
In what causes would ADH be released when the plasma osmolality is low?
 
In functional hypovolemia.  Even though there is not actually a decrease in ECF volume...
12
What is functional hypovolemia?
 
A state in which ECF can be massively expanded, but the body is reacting as is ECF volume is...
13
Give 4 examples of functional hypovolemia?
 
Congestive heart failureCirrhosisNephrotic syndromeAV shunting due to fistula or congenital...
14
Describe the feedback regulation of body water in response to water deficit.
 
Water deficit causes increased plasma osmolality, which triggers 2 things- ADH release and...
15
What is the main determinant of ECF volume balance?
 
Na+ balance in the bodyi.e. a constant amount of Na+ in the body
16
T/F.  Plasma Na+ concentration is a good indicator of the amount of Na+ in the body.
 
FALSE.  It does not tell you anything about the Na+ amount in the body.  For example,...
17
How is ECF volume related to Na+ content?
 
ECF volume is directly proportional to the amount of Na+ in the body.  SO if you have...
18
Why does it make sense that an increased salt intake would lead to an increased ECF and body...
 
If you're taking in additional salt, you are going to have increased reabsorption of salt from...
19
How fast does the body adjust the Na+ excretion rate to be equal to the increased Na+ intake?
 
It takes a few days for sodium excretion rate to match the new sodium intake rate, and during...
20
What is pressure natriuresis?
 
All else being equal, increases in blood pressure will cause increase in Na+ and water excretion.
21
What is salt-sensitive hypertension?
 
Increase Na+ intake in some hypertensives, and will increase their blood pressure even more....
22
What is the GT balance?
 
The nephron's ability to maintain a constant 2/3 reabsorption of NaCl from the PCT>
23
What is atrial natriuretic peptide (ANP)?
 
Released from the atria of the heart when stretch receptors in the walls of the atria are activated...
24
What are the 3 main actions of ANP?
 
1. Systemic relaxation of vascular smooth muscle, decreasing TPR.2. Relaxation of afferent...
25
What are the 2 effects of sympathetic tone on the nephron?
 
1. Decreases filtration2. Increases peritubular reabsorptive forces
26
Describe the effects of sympathetic tone on the nephron.
 
Constricts the efferent and afferent arterioles, which decreases the GFR.  This means...
27
______ can stimulate the proximal convoluted tubule to absorb more salt.
 
Angiotensin II, catecholamines
28
How do angiotensin II and catecholamines stimulate the PCT to absorb more salt?
 
They act directly on the cells of the PCT to increase Na/H antiporters in the lumenal membrane
29
________ and ______ are the 2 major hormones that act to increase Na+ reabsorption.
 
Aldosterone, angiotensin II
30
Where does aldosterone increase Na+ reabsorption from?
 
Acts on the medullary collecting duct
31
Where does Angiotensin II increase Na+ reabsorption from?
 
The PCT
32
Describe the response to hypovolemia (decreased ECF volume)
 
1. Release of renin, ADH, and NE2. Renin activates Ang II --> activates aldosterone, which...

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