L11 Flashcards
(167 cards)
1
Q
What percentage of the human body is water?
A
Approximately 55%
2
Q
What are the two major fluid compartments?
A
Intracellular and extracellular fluid
3
Q
Which fluid compartment holds the majority of water?
A
Intracellular fluid (ICF)
4
Q
What percentage of total body water does ICF account for?
A
2/3
5
Q
What are the two components of extracellular fluid (ECF)?
A
Interstitial fluid and plasma
6
Q
What percentage of ECF is interstitial fluid?
A
75%
7
Q
What percentage of ECF is plasma?
A
25%
8
Q
Where is interstitial fluid located?
A
Between cells
9
Q
What is plasma?
A
The fluid component of blood
10
Q
What are the primary sources of water gain?
A
Food and drink
11
Q
What is another source of water gain in the body?
A
Metabolic processes
12
Q
What is the primary route of water loss?
A
Urine
13
Q
How much water is typically lost through urine per day?
A
1.5 L/day
14
Q
What are other routes of water loss?
A
Skin (sweat), lungs (breath), feces
15
Q
What does excessive water loss disrupt?
A
Homeostasis
16
Q
What disease can result from excessive water loss?
A
Hypotension/shock
17
Q
What happens to blood pressure with excessive water loss?
A
Decreased blood pressure
18
Q
What are symptoms of excessive water loss?
A
Confusion, chest pain, very low blood pressure, minimal urine
19
Q
Where does excess water back up in the body?
A
Lungs, legs, and abdomen
20
Q
What difficulties arise from too much water?
A
Breathing, walking
21
Q
What is the consequence of decreased extracellular fluid?
A
Decreased blood pressure
22
Q
What organ is responsible for urine production?
A
Kidneys
23
Q
What can excessive fluid loss change?
A
Amount of fluid loss
24
Q
Where is blood filtered?
A
Through the bloodstream into the kidneys
25
What are the sections in the kidneys called where filtering occurs?
Nephrons
26
What is produced as a result of kidney filtration?
Urine
27
What are the main parts of the kidney shown in the diagram?
Cortex, medulla
28
What is the function of the ureter?
Transports urine to the bladder
29
What is the bladder's role in the urinary system?
Stores urine
30
What three processes form urine in the nephron?
Filtration, reabsorption, secretion
31
How much filtrate is formed per day?
180 L
32
How much urine is excreted per day?
1.8 L (1%)
33
How much blood flows to the kidneys per day?
1584 L
34
What happens to plasma in the nephron?
It is filtered
35
What may the body decide to do with filtered substances?
Reabsorb them
36
What might the body decide to secrete into the external environment?
More substances
37
What do filtration, reabsorption, and secretion contribute to?
How much urine one produces
38
What controls the tiny range of urine production?
Hormones
39
What is the nephron responsible for?
Excreting waste
40
What does the nephron regulate?
Blood volume
41
What does the nephron control?
Electrolytes
42
What does the nephron help maintain?
Blood pH
43
What vitamin is the nephron involved in producing?
Vitamin D
44
Where does blood enter the nephron?
Glomerulus
45
What happens to plasma in the glomerulus?
It is filtered
46
What are the three main processes in urine formation?
Filtration, reabsorption, and secretion
47
Where does filtration primarily occur in the nephron?
Proximal tubule
48
What is the osmolarity of the filtrate entering the nephron?
300 mOsM
49
What needs to happen to the majority of the filtrate?
It needs to be reabsorbed
50
Where does the majority of excess water reabsorption occur?
Collecting duct
51
What is osmolarity?
Concentration of solute particles per liter
52
What is the significance of the collecting duct?
Final fine-tuning of water production in urine
53
What is the effect of vasopressin on water reabsorption?
Increases it
54
What are the two main effects of aldosterone?
Na+ reabsorption and K+ secretion
55
What is the overall effect of atrial natriuretic peptide (ANP)?
Decreases Na+ and H2O reabsorption
56
What happens when water reabsorption increases?
Less urine is produced
57
What does aldosterone do to water reabsorption?
Increases it
58
Where is vasopressin synthesized?
Hypothalamus
59
Where is vasopressin secreted from?
Posterior pituitary
60
What is another name for vasopressin?
Antidiuretic hormone (ADH)
61
What does ADH prevent?
Excess urine production
62
Where is ADH released?
Into circulation
63
What type of hormone is ADH?
Peptide hormone
64
What is the primary function of ADH?
Increase water reabsorption in the kidneys
65
What does increased permeability in kidney cells lead to?
Increased reabsorption and low urine output
66
What are the effects of ADH on the body?
Conserves body water, maintains water balance, increases blood volume and pressure
67
How does ADH affect water balance?
Maintains fluid homeostasis
68
What happens when ADH increases permeability?
Increased reabsorption and low urine output
69
What is the most important stimulus for vasopressin release?
Osmolarity
70
How is low blood pressure detected?
Reduced stretch in the:
- Walls of the atria
- Aortic and carotid arteries
71
What detects osmolarity changes?
Osmoreceptors in the hypothalamus
72
What triggers ADH secretion in the hypothalamus?
High saltiness (excess ions)
73
What is the purpose of conserving water?
To dilute high ion concentration
74
Where does ADH travel after secretion?
To the kidneys
75
What are barrel receptors involved in?
Detecting changes in blood volume and pressure
76
What is the effect of ADH on the collecting duct?
Increased water permeability.
77
What happens to vasopressin levels within normal osmolarity ranges?
They are minimal
78
What triggers a significant increase in plasma vasopressin?
Exceeding the normal osmolarity range
79
What does a small increase in serum sodium indicate?
Increased osmolarity
80
What sensation can vasopressin release trigger?
Feelings of thirst
81
What is the normal range of plasma osmolarity?
270-290 mOs/kg
82
What is the effect of exceeding the normal osmolarity range?
Huge increase in plasma vasopressin
83
What does increased serum sodium lead to?
Vasopressin release
84
What is the relationship between osmolarity and vasopressin?
Osmolarity is the most potent stimulus for vasopressin release
85
What happens when plasma osmolarity increases?
Vasopressin is released
86
Where does vasopressin bind to?
Proper receptor on cells of nephrons
87
What does the signal cascade result in?
Insertion of aquaporin 2
88
Where are aquaporin 2 inserted?
Membrane side facing inside of nephron (apical)
89
What is the role of aquaporin 2?
Water pores
90
What happens when water travels through aquaporin 2?
Absorbed back into bloodstream
91
What is the effect of water being pulled into the bloodstream?
Lowers osmolarity in blood
92
What is the final destination of vasopressin?
Kidneys
93
What happens to the collecting duct in the presence of vasopressin?
Freely permeable to water
94
Where does water lead to?
Capillaries
95
What happens to the urine?
quite concentrated
96
What is the main function of vasopressin?
Anti-diuretic
97
What type of hormone is aldosterone?
Steroid hormone
98
Where is aldosterone synthesized?
Adrenal cortex
99
What is the first main function of aldosterone?
Na+ reabsorption
100
What does Na+ reabsorption lead to?
Retain water
101
What is the second main function of aldosterone?
K+ secretion
102
Where does aldosterone act?
Distal tubule and collecting duct
103
What is aldosterone closely tied to?
Water
104
What is the location of synthesis?
Zona Glomerulosa
105
What type of feedback controls aldosterone synthesis?
Negative feedback
106
Name a simple stimulator of aldosterone synthesis.
High plasma [K+]
107
What complex pathway stimulates aldosterone synthesis?
Renin-Angiotensin II
108
What inhibits aldosterone synthesis?
High osmolarity (extracellular fluid)
109
What system is the RAAS pathway?
Renin-angiotensinogen pathway
110
Where does aldosterone act?
Distal tubule and collecting duct
111
What is the primary action of aldosterone?
Sodium reabsorption
112
What is the net effect of aldosterone?
Increased Na+ reabsorption, increased K+ secretion
113
Where is aldosterone synthesized?
Adrenal cortex, zona glomerulosa
114
What is the chemical nature of aldosterone?
Steroid
115
What stimulates aldosterone release?
Low blood pressure, high K+
116
What inhibits aldosterone release?
Natriuretic peptides
117
What is the receptor for aldosterone?
Cytosolic mineralocorticoid (MR) receptor
118
How does aldosterone enter the cell?
Freely diffuses through the plasma membrane
119
Where does aldosterone translocate after entering the cell?
Nucleus
120
What does aldosterone influence in the nucleus?
Expression of Na+ and K+ channels and Na+/K+ ATPase
121
What does aldosterone prevent?
Degradation of apical Na+ channels
122
What does aldosterone increase the expression of?
Na+ and K+ channels and Na+/K+ ATPase
123
What is the result of increased Na+ reabsorption and K+ secretion?
Pumps back into blood as needed
124
What is the importance of the channels?
Help balance sodium and potassium
125
What is the location of the apical membrane?
The inside of the nephron
126
What enzyme do juxtaglomerular cells secrete?
Renin
127
When do these cells secrete renin?
When blood pressure falls
128
Where are juxtaglomerular cells located?
Where the bloodstream meets the nephron
129
What is the primary function of these cells?
To sense blood pressure
130
What part of the nephron do these cells interact with?
The glomerulus
131
What type of cells are juxtaglomerular cells?
Neurons
132
What is the significance of their location?
They can sense blood pressure changes
133
What triggers renin secretion?
A drop in blood pressure
134
What system is activated by renin secretion?
The Renin-Angiotensin-Aldosterone System (RAAS)
135
What is the starting point of the RAAS pathway?
A drop in blood pressure
136
What enzyme initiates the RAAS pathway?
Renin
137
Where is angiotensinogen produced?
In the liver
138
What converts angiotensin I to angiotensin II?
ACE (angiotensin-converting enzyme
139
Where does the conversion of angiotensin I to angiotensin II occur?
In the lungs
140
What are some effects of angiotensin II?
Increases vasopressin, stimulates thirst, vasoconstriction
141
What does angiotensin II stimulate the adrenal cortex to release?
Aldosterone
142
What type of molecules are natriuretic peptides?
Tiny peptide molecules
143
What is the primary function of natriuretic peptides?
To stimulate water release from the body
144
What type of glands secrete these peptides?
Secondary endocrine glands
145
Name three types of natriuretic peptides.
ANP, BNP, CNP
146
Where is ANP primarily released?
In the atria of the heart
147
What cells release ANP?
Myocardial cells and neurons
148
Where is BNP primarily released?
In the ventricles of the heart
149
What cells release BNP?
Myocardial cells and neurons
150
Where is CNP primarily released?
Brain, pituitary, vessels, kidneys
151
What is the overall effect of natriuretic peptides?
To lower blood pressure
152
What was the key finding in the research by de Bold et al.?
They found a rapid and potent natriuretic response to atrial myocardial extract in rats
153
What are the two main types of natriuretic peptides mentioned?
Atrial Natriuretic Peptide (ANP) and Brain Natriuretic Peptide (BNP)
154
What is a key effect of natriuretic peptides on sodium and water reabsorption?
They decrease Na+ and H2O reabsorption
155
What is the effect of natriuretic peptides on potassium reabsorption?
They increase K+ reabsorption
156
Which other hormones do natriuretic peptides suppress?
Renin, aldosterone, and vasopressin
157
What stimulates the release of these peptides from the heart?
Stretch of the heart chambers (atria and ventricles)
158
What does sensing heart stretch indicate to the body?
It can indicate too much pressure or volume
159
What is the primary stimulus for ANP release shown in the diagram?
Increased blood volume causing atrial stretch
160
What cells sense the atrial stretch and release natriuretic peptides?
Myocardial cells
161
How does ANP affect sodium reabsorption in the tubule?
It decreases Na+ reabsorption
162
What happens to NaCl and H2O excretion as a result of ANP?
It increases
163
How does ANP affect blood volume?
It decreases blood volume
164
What is the ultimate effect of ANP on blood pressure?
It decreases blood pressure
165
How does ANP affect renin release?
It decreases renin
166
How does ANP affect aldosterone release?
It decreases aldosterone
167
How does ANP affect vasopressin release?
It decreases vasopressin
