Urinary System Flashcards
1
Q
The urinary system regulates:
A
- plasma composition (ions)
- plasma volume + pressure
- plasma osmolarity
- plasma pH
2
Q
The urinary system indirectly regulates:
A
MAP through solute and water composition in plasma
3
Q
How does the urinary system regulate plasma pH?
A
through H+ ions and HCO3- with the lungs and blood buffering system
4
Q
The urinary system removes:
A
- metabolic waste
- foreign substances
5
Q
How does the urinary system remove metabolic waste?
A
- Removal of metabolic wastes from nutrient breakdown (urea, uric acid from proteins and nucleic acids)
- waste products entering the body ie. Food additives, drugs
6
Q
Name some other functions of the urinary system.
A
- secrete EPO and renin
- activate vitamin D3 to calcitriol
- gluconeogenesis
7
Q
The secretion of EPO does what?
A
- makes them endocrine organs
- EPO signals bone marrow to increase production of RBCs
8
Q
The secretion of renin does what?
A
renin involved with RAAS system that regulates MAP
9
Q
Vit D activation is necessary to:
A
regulate calcium in the blood
10
Q
What is gluconeogenesis?
A
creates glucose from non-carbohydrate intermediates (as necessary ie. CHO low)
11
Q
Describe the kidneys.
A
- paired
- bean shaped
- approximate size of fist: 115-170 g
- retroperitoneal
- from urine
12
Q
What do ureters do?
A
transport urine from kidneys to bladder
13
Q
What does the bladder do?
A
store urine
14
Q
What does the urethra do?
A
excrete urine from bladder to outside of body
15
Q
nephron =
A
functional unit
16
Q
Renal corpuscle consists of:
A
- glomerulus
- Bowman’s capsule
17
Q
glomerulus =
A
capillary network for filtration
18
Q
What does the Bowman’s capsule do?
A
- receives the filtrate
- inflow to renal tubules
19
Q
Renal tubules consists of:
A
- proximal tubule
- Loop of Henle
- distal convoluted tubule
- collecting duct
20
Q
What makes up the proximal tubule?
A
- proximal convoluted tubule
- proximal straight tubule
21
Q
What makes up the Loop of Henle?
A
- descending limb
- thin ascending limb
- thick ascending limb
22
Q
What makes up the distal convoluted tubule?
A
connecting tubule
23
Q
What are the 2 types of nephrons?
A
- cortical
- juxtamedullary
24
Q
Describe cortical nephrons.
A
- short loop of Henle
- most numerous, 80-85%
25
Describe juxtamedullary nephrons.
- long loop of Henle extends into medulla
| - responsible for the medullary osmotic gradient
26
Which type of nephron produces urine?
both types
27
Loop of Henle establishes conditions necessary to....
- concentrate urine
| - minimizes water loss
28
Juxtaglomerulus apparatus cell location:
- DCT
| - afferent arteriole + some efferent
29
Macula densa =
- secretes paracrines based on changes in fluid movement and sodium concentration past the cells
- impacts smooth muscle of afferent arteriole
30
Juxtaglomerular cells (granulosa cells) =
- secrete renin (renin-angiotensin-aldosterone system (RAAS))
- located in the afferent arteriole + few in the efferent arteriole
31
Renal arteries enter the kidney at the _____.
hilus
32
Renal arteries receive ___% of cardiac output at rest.
20%
33
Renal veins exit at ______.
hilus
34
Peritubular capillaries associated with...
efferent arteriole of cortical nephrons
35
Vasa recta (straight vessels) associated with...
efferent arterioles of the juxtamedullary nephrons
36
Movement of protein-free plasma from _____ to _____ _____.
glomerulus to Bowman's capsule
37
Glomerular filtrate crosses 3 barriers to Bowman's:
- capillary endothelial layer
- surrounding epithelial layer
- basement membrane
38
Glomerular filtration is from ______ to ______ _____.
glomerulus to Bowman's capsule
39
Reabsorption if from _____ to _____ ______.
tubules to peritubular capillaries
40
Secretion is from _____ _____ to ______.
peritubular capillaries to tubules
41
Excretion is from ____ to ______.
tubules to out the body
42
What do podocytes do?
provide gaps for movement of material
43
Describe starling forces that favour filtration.
- glomerular capillary hydrostatic pressure
| - Bowman's capsule oncotic pressure
44
Describe glomerular capillary hydrostatic pressure.
- 60 mm Hg
| - high due to resistance of efferent arteriole
45
Describe Bowman's capsule oncotic pressure.
- 0 mm Hg
| - low due to lack of protein in filtrate
46
Describe starling forces that oppose filtration.
- Bowman's capsule hydrostatic pressure
| - glomerular oncotic pressure
47
Describe Bownman's capsule hydrostatic pressure.
- 15 mm Hg
| - relatively high (compared to systemic capillaries) due to large volume of filtrate in closed space
48
Describe glomerular oncotic pressure.
- 29 mm Hg
| - higher than in systemic capillaries due to plasma proteins in smaller volume of plasma
49
Name 3 ways for intrinsic regulation of GFR.
- myogenic regulation
- tubuloglomerular feedback
- mesangial cells
50
Describe myogenic regulation.
- smooth muscle in wall of afferent arteriole
| - contracts in response to stretch (from increases to MAP) to maintain GFR (vv. if MAP falls)
51
Describe tubuloglomerular feedback.
- Macula densa cells secrete paracrine factors in response to an increase in flow of fluid past them
- smooth muscles of arterioles contract in response to these paracrinse
52
Describe mesangial tubuloglomerular feedback.
reduced SA for filtration (reduces flow to some capillaries)
53
Describe extrinsic tubuloglomerular feedback.
both afferent and efferent arterioles are constricted (decr. GFR, incr. MAP)
54
Extrinsic control of GFR is influenced by _____. _____ changes accordingly
- MAP
| - GFR
55
Kidneys have the ability to deal with changes to MAP within ___ to _____ mm Hg. Beyond this range:
- 80-180 mm Hg
| - beyond this range, GFR is altered (falls below "normal" or increases above "normal")
56
Reabsorption most occurs in ____ _____ and most is/is not regulated.
- proximal tubules
| - not regulated
57
Describe solute reabsorption.
- most occurs in PCT
- some occurs in DCT
- 100% glucose reabsorbed (most other ions and water as well)
58
What can effect the rate of transport?
- can occur with carriers
| - if carriers saturated, some solute is excreted
59
When solute is transported across epithelium by carrier proteins, _______ can occur when solute concentration rises
saturation of carriers
60
What is renal threshold?
plasma concentration at which spillover into urine occurs
61
Name 5 secreted substances.
- potassium
- hydrogen ions
- choline
- creatinine
- penicillin
62
______ reabsorption in the proximal tubules.
non-regulated
63
______ reabsorption and secretion in the distal tubules and collecting ducts.
regulated
64
Water conservation in the ________ because it:
- loop of Henle
| - concentrates urine
65
____ _____ is the mass reabsorber.
- proximal tubule
66
Proximal tubule reabsorbes ____% sodium and water.
70%
67
Proximal tubule reabsorbes ____% glucose.
100%
68
_____ ____ in the proximal tubule provides for large surface area.
brush border
69
____ ____ _____ in the proximal tubule allow paracellular transport.
leaky tight junctions
70
____ increases surface area.
villi
71
What drive active transport?
many mitochondria
72
In the distal tubule, transport is regulated across ______.
epithelium
73
____ _____ limit paracellular transport.
tight junctions
74
There are ____ mitochondria in the distal tubule.
fewer
75
What does aldosterone do?
Na+ reabsorption
76
What does ANP do?
opposes Na+ reabsorption
77
What does ADH do?
water retention/reabsorption
78
Amount of substance excreted =
amount filtered + amount secreted - amount reabsorbed
79
Amount excreted depends on 3 factors:
- filtered load
- secretion rate
- reabsorption rate
80
If amount of solute excreted per minute is less than filtered load:
solute was reabsorbed
81
If amount of solute excreted per minute is greater than filtered load:
solute was secreted
82
Micturition =
urination
83
Urine formed in ____ ____.
renal tubules
84
Fluid drains into ____ _____ and into _____.
- renal pelvis
| - ureter
85
Ureters lead to ______.
bladder
86
_____ stores urine until it is excreted.
bladder
87
Describe what happens in terms of blood flow and the urinary system when we exercise.
- 25% below resting
- blood flow to kidneys reduced in favour of active muscles
- primary factor is to offset vasodilation in muscles
- more Na+ reabsorbed
88
Describe the intensity effect.
- proteinuria (RBCs and WBCs)
| - hydration can offset this
89
Describe the reduction in BP with training.
decreased circulating NE (due to decreased sympathetic activity) with training
90
Gluconeogenesis at the kidneys increases by ____% following exercise.
- 50%
| - lactic acid is converted to glucose
91
Recovery from dehydration and changes in electrolytes from exercise, particularly:
heavy intensity, long duration persists for hours/days following
