Chapter 42 Flashcards
1
Q
What is the purpose of the urinary system?
A
- blood plasma balancer
- adjusts ions, water, and pH
2
Q
What are the accessory organs of the urinary system?
A
- ureters
- urinary bladder
- urethra
3
Q
Where are the kidneys?
A
- retroperitoneal
- T12-L3
- liver pushes the right kidney lower
4
Q
What is the perirenal fat pad?
A
-fat surrounding the kidney
5
Q
What is the hilum?
A
-where the veins, arteries, nerves, and ureters enter and leave the kidney
6
Q
What is the fibrous capsule?
A
-dense CT that surrounds the kidney
7
Q
What is the internal anatomy of the kidney?
A
- renal cortex
- renal medulla
- renal papilla
- minor and major calyx
- renal pelvis
- nephrons
8
Q
What is the glomerulus?
A
-knot of fenestrated capillaries for increased porosity for filtration
9
Q
What is the blood supply of the kidney? (trace is from aorta to IVC)
A
- aorta->thoracic aorta->abdominal aorta
- renal artery->segmental arteries->interlobar arteries
- arcuate arteries->interlobular arteries->afferent arteriole
- glomerular capillaries->efferent arterioles->peritubular capillaries
- interlobular veins->arcuate veins->interlobar veins
- renal vein->inferior vena cava
10
Q
What makes up the nephron?
A
- renal corpuscle: glomerulus and Bowmans capsule
- renal tubule: proximal tubule, loop of Henle, distal tubule, and collecting duct
11
Q
What is the Bowman capsule?
A
-cup shaped mouth of the nephron
12
Q
What is the function of the Bowman capsule?
A
- two epithelial layers with a space in between where fluid, waste, and electrolytes pass through
- filtrate
13
Q
What are podocytes? Function?
A
- cells in the glomerular capsule
- filtration slits
14
Q
What are pedicels?
A
- the feet of the podocytes that wrap around the capillaries
- this forms the filtration slits
15
Q
Why is it important to know that the ascending loop is thick? What is best transported here?
A
-
-sodium, potassium, calcium, chloride, magnesium
16
Q
What are the different routes of reabsorption in the proximal tubule?
A
- paracellular reabsorption: in between the cells
- transcellular reabsorption: through the cells
17
Q
How does reabsorption in the proximal tubule of negative ions and urea occur?
A
-since sodium is reabsorbed and positive, it pulls the negative ions out
18
Q
How does reabsorption in the proximal tubule of water occur?
A
-water gets reabsorbed because of the high osmotic pressure
19
Q
Which hormones regulate reabsorption and secretion of the tubular?
A
- antidiuretic
- RAAS
- atrial natriuretic
- parathyroid
20
Q
What does antidiuretic hormone do? What stimulates its secretion? What secretes is?
A
-posterior pituitary
21
Q
What it the renal tubule? Function?
A
- the winding, hollow tube of the nephron (everything except the renal corpuscle)
- allows for reabsorption and secretion
- detects changes in the composition and flow of filtrate
22
Q
What does angiotensin II do? What does it stimulate?
A
- vasoconstriction which decreases GFR
- aldosterone
23
Q
What is the juxtaglomerular apparatus?
A
- afferent arteriole that gets really close to the distal tubule
- right off the renal corpuscle
24
Q
What are juxtaglomerular cells? Function?
A
-cells in the wall of the arteriole that secrete renin
25
What is the macula densa? Function?
- tightly packed cells in the distal tubule
| - measure sodium chloride levels in filtrate
26
What is the collecting duct? Function?
- where the distal tubule drains into
- converges with several other ducts and tubules which then extends into the medulla
- releases urine into a minor calyx
27
What is the renal papilla?
-the point where the collecting ducts from the pyramids release urine into the minor calyces
28
Where is urine released?
-minor calyx
29
What is the blood supply to the nephron?
- afferent arteriole
- glomerular capillaries
- efferent arteriole
30
What are peritubular capillaries? Vasa recta?
- capillaries which surround the renal tubule
| - vasa recta are the capillaries that follow the loop of Henle
31
What are cortical nephrons?
-85% of nephrons that remain in the cortex
32
What are juxtamedullary nephrons?
-15% of nephrons that extend down into the medulla
33
What is the function of the kidney?
- maintain fluid-electrolytes balance
| - secretion of hormones
34
What hormones are secreted by the kidney?
- erythropoietin
- aldosterone
- vitamin D
35
What hormones influence the action of the kidney?
- RAAS
- aldosterone
- ADH
- ANH
36
What are the three basic processes of the production of urine?
- filtration (glomerulus)
- tubular reabsorption
- tubular secretion
37
What is glomerular filtration? Where does it occur?
- movement of water and solutes from glomerular capillaries into Bowman's capsule and into the renal tubule
- glomerulus
- fenestrations allow faster filtration
38
What makes up the filtration membrane?
- podocytes
| - capillary (glomerular) endothelial cells
39
What three layers does the filtrate cross to get into the Bowman capsule? Function
- glomerular endothelial cells: fenestrated capillaries
- basal lamina: prevents filtration of large plasma proteins
- filtration slits of podocytes: allow most small molecules to pass
40
What is effective filtration pressure?
-the net driving force which pushes fluid into Bowman's capsule
41
What is glomerular blood hydrostatic pressure? What does it do?
- blood pressure in glomerular capillaries
| - promotes filtration
42
What is capsular hydrostatic pressure? What does it do?
- pressure exerted by fluid already in capsular space
| - opposes filtration
43
What is blood colloid osmotic pressure? What does it do?
- pressure exerted by presence/concentration of blood proteins
- opposes filtration
44
What is glomerular filtration rate? (GFR)
- the rate of movement of fluid out of the glomerulus and into the capsular space
- filtration per minute
45
What happens if the GFR is too high or too low?
- too high: substances pass too quickly without being reabsorbed
- too low: everything is reabsorbed and wastes are not excreted
46
How does the GFR relate to effective filtration pressure?
-the higher the GFR, the higher the EFP
47
How is the GFR changed?
- adjustment to blood flow via vasodilation or vasoconstriction
- alteration of glomerular capillary surface area also via vasodilation or vasoconstriction
48
How is the GFR regulated?
- myogenic mechanisms
| - tubuloglomerular feedback
49
What is the myogenic mechanism?
- high BP: stretching of vessel walls that triggers vasoconstriction of afferent arterioles; decreases blood flow
- low BP: vessel walls relax causing dilation of afferent arterioles; increases blood flow
50
What is the tubuloglomerular feedback mechanism?
- the macula densa cells sense increased delivery of ions and water
- they inhibit nitric oxide which causes vasoconstriction of afferent arterioles
- this is slower than myogenic mechanism
51
What is tubular reabsorption?
-occurs along the renal tubule (mostly the proximal tubule) where active and passive transport allow materials to go back into the blood
52
What is the difference between reabsorption and absorption? Where does it mostly occur?
- reabsorption happens after water and ions are filtered out of your blood and then into the kidneys
- they get reabsorbed back into your blood in the renal tubule
- mainly in proximal tubule
53
What molecules in the urinary tract use sodium cotransport?
- glucose
| - amino acids
54
What are antiporters?
-they allow one thing in and one thing out at the same time
55
Which ions use antiporters? Which ion comes into the cell and which goes out? How can this be used to regulate blood pH?
- sodium and hydrogen
- sodium go into the cells and into blood
- hydrogen goes out of cells and into tubule
56
How would urine volume change with each hormone?
- absence of ADH = dilute urine
- presence of ADH = concentrated urine
- absence of ANH = more concentrated urine
- presence of ANH = more dilute urine
57
What is micturition?
- urination
- involuntary contractions of the detrusor muscle
- control from external urethral sphincter
58
Which ions use antiporters? Which ion comes into the cell and which goes out?
- sodium and hydrogen
- sodium go into the cells and into blood
- hydrogen goes out of cells and into tubule
59
Why is it important to know the descending loop is thin? What is transported best here?
- the descending loop is best for urea and water transport
| - it is impermeable to ions
60
Why is it important to know that the ascending loop is thick? What is best transported here?
- it is impermeable to water
- best for ion transport
- sodium, potassium, calcium, chloride, magnesium
61
What important cation is mostly reabsorption in the distal convoluted tubule? What hormone stimulates this?
- calcium
| - parathyroid hormone
62
What other ions are reabsorption in the distal convoluted tubule?
- sodium
- chloride
- 10-15% of water
63
What are principal cells? Where are they found?
- cells that reabsorb sodium and secrete potassium
| - found in the collecting duct
64
What are intercalated cells? where are they found?
- cells that reabsorb potassium and bicarbonate and that secrete hydrogen
- found in the collecting duct
65
What does antidiuretic hormone do? What stimulates its secretion? What secretes is?
- retains water; raises blood pressure
- plasma osmolarity
- posterior pituitary
66
What is the difference between antidiuretic function and aldosterone function? Why must they work together?
- antidiuretic: causes the kidneys to take up water
- aldosterone: causes the kidneys to take up salt
- they need water and sodium to both go through to raise blood pressure
- both help with putting water back in blood
67
What is osmolarity? How does it change during the course of the nephron?
- the concentration of water to ions
| - the percent decreases as it goes down the nephron; highest in the proximal tubule
68
What is the RAAS?
- juxtaglomerular cells secrete renin
- this causes angiotensinogen to be converted into angiotensin 1
- ACE (lungs) converts angiotensin 1 into angiotensin 2
- this causes vasoconstriction which lowers GFR and stimulates the release of aldosterone by the adrenal cortex
