Urinary System Flashcards
1
Q
Name the functions of the kidney
A
- Excretion of wastes
-H20 balance (plasma volume)
-Blood pressure control (renin) - acid-base balance
- blood cell production (erythropoietin)
- vitamin d activation
2
Q
What does the urinary system consist of?
A
- Kidneys
- blood supply (20%)
- transport vessels
3
Q
What are the 3 transport vessels in the urinary system?
A
- Ureters
-Urinary bladder - urethra
4
Q
What are the 2 types of nephrons?
A
- Cortical
-juxtamedullary
5
Q
Which type of nephron is shorter?
A
Cortical
6
Q
Which type of nephron controls the osmotic gradient?
A
Juxtamedullary
7
Q
What type of nephrons are there more of?
A
Cortical
8
Q
What are the vascular components of the nephron?
A
- Renal artery
- efferent arteriole
-Glomerulus
-Efferent arterial - peritubular capillaries
- renal vein
9
Q
What are the parts of the tubule? (In order)
A
- Bowman’s capsule
- Proximal tubule
- Loop of henle (ascending, descending)
- Distal tubule
- Collecting duct
10
Q
What are the 3 renal processes?
A
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
11
Q
Where does filtration occur?
A
Bowman’s capsule
12
Q
Where does reabsorption occur?
A
Loop of henle, proximal tubule, distal tubule, collecting ducts
13
Q
Where is the osmotic gradient created?
A
Loop of henle
14
Q
In what part of the tubule is reabsorption hormone controlled?
A
Distal tubule
15
Q
What is filtered in the glomerulus?
A
Everything but RBC’s and proteins (too big)
16
Q
What is reabsorbed?
A
Na, cl, ca, PO4, water, glucose
17
Q
What is secreted?
A
K,H, large organic
18
Q
What is the glomerulus?
A
Fenestrated tuft of capillaries surrounded by bowman’s capsule
19
Q
What are the 3 layers of the glomerular membrane?
A
- glomerular capillary wall
- basement membrane (acellular gelatinous layer, collagen and glycoproteins)
Inner layer of bowman’s capsule (consists of podocytes that encircle the glomerulus tuft)
20
Q
How much is filtered a day in the glomerulus?
A
160 -180L/day ( 125ml/min)
21
Q
What moves into tubules in glomerular filtration?
A
Electrolytes, water, glucose (RBC’s and most proteins are too big to be filtered)
22
Q
True/false: podocytes can change shape
A
True
23
Q
What do podocytes do?
A
Control filtration
24
Q
What happens during renal failure in relation to podocytes?
A
Large slits form allowing proteins and rbc’s in
25
What are the 3 main forces involved in glomerular filtration?
1. Glomerular capillary blood pressure
2. Plasma - colloid osmotic pressure
3.bowman's capsule hydrostatic pressure (hydrostatic wants to more water out)
Bowman's capsule osmotic pressure has small effect
26
Which forces favour glomerulus filtration?
Glomerular blood pressure
27
Which forces opposes filtration?
-Plasma-colloid osmotic pressure
- bowman's capsule hydrostatic pressure
28
What is the glomerular filtration rate dependant on?
- Net filtration pressure
- glomerular surface area available for penetration
- permeability of the glandular membrane (podocytesslit size can change with infection)
29
True/false: GFR won't change if the blood hydrostatic pressure changes
False (will change)
30
How is GFR auto-regulated?
-tubuloglomerular feedback ( local (paracrine) control)
- hormones/autonomic (Change arteriole resistance)
31
Afferent arteriole __________ will lower GFR
Constriction
32
Afferent arteriole __________ will increase GFR
Dilation
33
Efferent arteriole __________ will lower GFR
Dilation
34
Efferent arteriole __________ will higher GFR
Constriction
35
What controls long-term regulation of arterial BP?
Sympathetic control (input to afferent arterioles, baroreceptor reflex)
36
Does lower blood pressure mean higher or lower GFR?
Lower GFR (and retention of fluids)
37
How do you measure GFR?
Use inulin (No reabsorption or secretion so excretion = filtration)
38
True/false: trans-cellular transport can be active or passive
True
39
How are Na and glucose moved?
Trans-cellular transport
40
What is paracellular transport?
Passive only (diffusion of water, ions)
41
What are the 2 ways things are reabsorbed in tubular reabsorption?
- Passive and active reabsorption
42
What is passive reabsorption?
No energy, down electrochemical or osmotic gradients
43
What is active reabsorption?
Requires energy, moves against electrochemical gradient
44
How is Na reabsorbed?
- Active process
-na-k ATPase pump in absolute rail membrane
45
Where is 67% of Na reabsorbed?
Proximal tubule
46
What is the role of Na reabsorption?
Plays role in reabsorbing glucose, amino acids, water, chlorine, urea
47
Where is 25% of Na reabsorbed?
Ascending loop of henle
48
What is the role of Na reabsorption in the ascending loop of hence?
Plays critical role in kidneys ability to produce urine of varying concentrations
49
Where is 8% of Na reabsorbed?
Distal and collecting tubules
50
What is the role of Na reabsorption in the distal and collecting tubules?
Variable and subject to hormonal control; plays role in regulating ECF volume
51
How does the na/k pump facilitate Na reabsorption?
Creates Na gradient across membrane
52
How is water reabsorbed?
Via osmotic gradient created by Na reabsorption
53
How is Cl reabsorbed?
Via electrical gradient
54
How is glucose reabsorbed?
By carriers (sodium linked glucose réabsorption in the proximal tubule)
55
What is tubular maximum?
When all glucose carriers are full (excess glucose stays in tubules and is lost in the urine)
56
What is renal threshold?
Blood glucose level where the carriers are full and glucose is seen in the urine
57
What is a disease where we see renal threshold reached frequently?
Diabetes mellitus
58
How is urea reabsorbed?
Through a passive process only till equilibrium is reached (50%)
59
True/false: urea is small and diffusible
True
60
How much glucose is reabsorbed?
100%
61
How much urea is reabsorbed?
50%
62
What does aldosterone control?
Na/k ATPase pumps
63
When is aldosterone released?
If blood volume is low
64
What does high aldosterone cause?
- increased speed of pump
-Inc Na reabsorption
-Inc water reabsorption (decreased urine)
65
True/false: aldosterone is decreased when dehydrated
False ( inc to inc water reabsorption)
66
What does the renin-angiotensin-aldosterone system (raas) regulate?
Na and blood pressure/volume
67
What is atrial natriuretic peptide (anp) antagonist to?
Aldosterone
68
What does ANP do?
-Inactivates na/k pump
-Inhibits Na reabsorption
69
When is ANP secreted by the atria?
- Inc blood pressure
- inc Na
- inc stretch of atria (inc volume)
70
What is secretion?
Transfer of molecules from extracellular fluid into tubule
71
Is secretion a passive process?
No, active
72
How is k+ secreted?
Na/k pump (later reabsorbed)
73
How is h+ secreted?
Acid-base balance
74
How are large organic secreted?
Biotransformed
75
What is the main thing that happens in the collecting ducts?
Water reabsorption
76
What is water reabsorption in the collecting ducts controlled by?
ADH
77
What does water reabsorption in collecting ducts require?
Osmotic gradient from loop of hence
78
True/false: descending loop of henle impermeable to water and permeable to salts
False, permeable to water, impermeable to salts
79
Which part of the loop of henle does filtrate become more concentrated?
Descending
80
Which part of the loop of henle does filtrate become less concentrated?
Ascending
81
True/false: ascending loop of henle permeable salts and impermeable to water
True
82
Which part of the loop of henle actively reabsorbs NaCl
Ascending
83
What is the vessel following the loop of henle?
Vasa recta (has similar osmotic gradient in blood supply)
84
What does the loop of henle do?
Creates a large vertical osmotic gradient in medulla (100 → 1200 mosm/ L)
85
How is water reabsorbed?
ADH cause insertion of water pores into the apical membrane
86
When is ADH (anti-diuretic hormore) released?
If blood osmolarity is high
87
What does ADH control?
Permeability of collecting ducts
88
What happens with low ADH?
Dilute, high volume of urine (water not reabsorbed
89
What happens with high ADH?
Lower volume of concentrated unive (reabsorb more water)
Dehydrated
90
What happens when you’re dehydrated?
- Inc ADH
- inc aldosterone
- Dec ANP
- inc water reabsorption → Dec urine (more concentrated)
91
What are some behavioural mechanisms related to the kidneys?
- Drinking replaces fluid loss
- low sodium stimulates salt appetite
Avoidance behautors help prevent dehydration (desert animals avoid the heat)
92
What happens with water loading?
- ADH decreases
- aldosterone also decreases
- ANP inc
-dec water reabsorption
- more urine, less concentrated
93
How much Na, Cl and water is reabsorbed in the proximal tubule?
67%
94
True/false: 100% of glucose and amino acids are reabsorbed in the proximal tubule
True
95
What happens to k in the proximal tubule?
Small amount is secreted/ reabsorbed
96
What happens to h+ in the proximal tubule?
Variable secretion
97
T/f: organic ion secretion in proximal tubule is controlled
False, not controlled
98
T/f: phosphate and electrolyte reabsorption in proximal tubule is controlled and variable
True
99
Does urea reabsorption occur in the proximal tubule?
Yes
100
What happens in the distal tubule?
-variable Na reabsorption (controlled by aldosterone and anp)
-variable water reabsorption (controlled by aldosterone and anp)
-variable K secretion/reabsorption (controlled by aldosterone)
-variable H secretion (depends on acid-base balance)
101
What happens in the collecting ducts?
-variable water reabsorption (controlled by ADH)
-variable H secretion
-variable urea reabsorption (related to loop of henle)
102
What does excretion =?
Filtration-reabsorption + secretion
103
What is clearance?
Rate at which a solute disappears from the body
- non-invasive way to recastre GFR (inulin, creatinine)
104
What does renal clearance equal?
RC =uv /p
-U= concentration of substance in urine
-V= flow rate of urine formation (GFR)
-P = concentration of same substance in plasma
105
What is inulin clearance equal to?
GFR
106
What is glucose clearance equal to?
Usually 0 (100% reabsorbed)
107
What is micturition?
Urination reflex
108
How does the urination reflex work?
Autonomic control of sphincters and detrusor muscle (CNS can override or initiate-stretch receptors)
109
What occurs during filling of bladder?
Detrusor muscle relaxed, sphincters contracted
110
What occurs during micturition?
Stretch receptors increase their firing
-sphincter relaxe, detrusor contracts, you pee
111
What are causes of acute renal failure?
-Infections/toxic agents
-Innappropriate immune responses
- obstruction of urine flow
-Insufficient renal blood supply
112
What are causes of chronic renal failure?
- Hyper tension
- diabetes (type 2)
- chronic exposure to toxins/drugs
113
What happens with renal failure?
-Build up of wastes to toxic levels
-Loss of calcium (osteoporosis)
- Na and k imbalance (affects nerve and muscle)
- loss of proteins -edema
- loss of rbc's - anemia
- low BP (Dec renin)
114
What are kidney stones?
Crystallization of minerals in either kidney, ureters or bladder
Calcium, oxalates (from veggies with rich colours), dehydration (binge drinking)
115
What is the normal ph range?
7.38 - 7.42 (veins more acidic then arteries)
116
What does absformal pt affect?
Can alter tertiary structure of proteins
Affects nervous system
117
What happens with acidosis?
Neurons became less excitable (cns depression)
118
What happens with altealosis?
Neurons are hyperexcitable
119
When is pH disturbed?
When k+ is disturbed
120
What is metabolic acidosis?
Metabolic organic acid production (lactic acid, ketoacids)
121
What is respiratory acidosis?
Production of CO2 (acid production)
122
What is metabolic alkalosis?
Dietary sources of bases (tums)
-vomiting
-pyloric stenosis
123
What is respiratory alkalosis?
Hyperventilation (high altitude)
124
How do we maintain pH homeostasis?
Buffers (fastest)
-combine with or release H
Ventilation
-75% of disturbances
Renal regulation (30 min, slowest)
-directly excreting or reabsorbing H
125
What ave some examples of buffers?
_Phosphate
- protein (hemoglobin)
-Bicarbonate
126
How does renal compensation work?
Either retains or eliminates h+ or HCO3 -
127
How does the body correct for acidosis?
To raise pH:
- buffers bind to h+
- breathing increases (Dec CO2 and H+ via carbonic acid)
- kidney excerpts H+ and keep bicarbonate
128
What type of interrelated cells function in acidosis?
Type A
129
What do type an intercalated cells do?
Secrete h+, reabsorb bicarb
130
What is the body's correction for alkalosis?
To lower pH
-buffers release H+
-Breathing slows down (retains C02 and H+)
-Kidney retains H+ and secretes bicarbonate
131
What type of intercalated cells function in alkalosis?
Type B
132
What do type b intercalated cells do?
- Secrete bicarb
-Reabsorb h+
