Renal 1: Introduction to the kidneys --> from blood plasma to urine (filtration) Flashcards
1
Q
What are the 4 functions of the kidneys?
A
- Regulates the extracellular fluid (ECF)
- Acid-base balance (maintenance of pH)
- Waste disposal
- Hormone production
2
Q
How is the ECF regulated?
A
- ECF volume
- Water & Na+balance
- Electrolyte composition
- Na+, Cl-, K+, Ca2+, H+ (pH= acidic), bicarbonate, phosphate, sulfate, magnesium
- Osmolarity
- 300 mOsm/L (needs to maintain this)
3
Q
What is waste that needed to be disposed thorough the kidneys?
A
Waste disposal –Eg. Urea & foreign compounds (drugs etc)
4
Q
What are the hormones that are produced by the kidneys?
A
Erythropoietin (production of red blood cells), renin (blood volume), vitamin D activation (vit. D for blood Ca+)
5
Q
Urine _____ varies as the kidneys maintain homeostasis
A
composition Eg. eat salty –> get rid of salt –> pee out salt
6
Q
What is the structure of the renal system?
A
7
Q
Where are the kidneys located?
A
8
Q
The ___ kidney is lower than __. Why?
A
R; L
make space for the liver (which takes up a lot of space)
9
Q
Kidneys are _____ (intra/retroperitoneal). What does that mean?
A
retroperitoneal behind the peritoneal cavity- surround by fat and connective tissue (“retro”= behind)
10
Q
What is the structure of the kidney?
A
11
Q
What are the 5 main structures of the kidney
A
- Outer cortex
- Renal pyramid (inner medulla)
- Calyces
- Renal pelvis
- Ureter
12
Q
Where does urine travel from? (start in the renal pyramids)?
A
- Urine drains from renal pyramids into calyces into renal pelvis (dilated part)
- Urine leaves via the ureter
13
Q
The renal system is __ (highly/lowly) vascularised? Why?
A
very highly vascularised- due to function for homeostasis
14
Q
The kidneys make up < 0.5% body weight, but receive ______ of the cardiac output
A
20%
15
Q
What is the nephron?
A
- (smallest part of kidney that carries out function- where urine is being produced)
- Functional units of the kidneys
16
Q
What are 3 structures are found in the nephron?
A
- Renal corpuscle (filtered)
- Renal tubule
- Collecting system (–> ureters)
17
Q
What happens at the glomerulus?
A
capillary bed- where blood is filtered
18
Q
What happens at the Bowman’s capusle?
A
(funnel/cup- being captured)
19
Q
What is the proximal tubule?
A
closest to renal corpuscle convoluted
20
Q
What is the sequence of urine flowing in the nephron to the collecting duct (to the ureter)?
A
- Glomerus
- Bowman’s capsule
- Proximal convoluted tubule
- Loop of Heenle
- Distal tubule
- Collectig duct
- Ureter
21
Q
What are the 2 types of nephrons?
A
- Cortical nephrons
- Juxtamedullary nephrons
22
Q
What are 3 characteristics of cortical nephrons?
A
- 80%
- Short loop of Henle
- Mostly in cortex (sit very high up/to the surface of kidney)
23
Q
What are 3 characteristics of juxtamedullary nephrons?
A
- 20%
- Long loop of Henle
- Dips deep into medulla
24
Q
What are the juxtamedullary nephrons important for?
A
Important for balance Na+ and H20
25
What is the vascular component of the cortical nephron?
26
Where are the vessels for the nephrons?
Surrounding
27
Wha are efferent arterioles?
Remaining blood --\> peritubular
28
What is the glomerus?
Blood is filtered
29
What is the afferent arteriole?
Heads towards glomerus
30
What are peritubular capillaries?
* wrap around nephron - molecules such as Na and glucose move between fluid inside tubule and peritular capillaries
* important that they are close--\> flux between these 2
31
What is the vasa recta?
head down and around Loop of Heenle
32
What is the pathway for the blood in the nephon?
1. Afferent arteriole glomerulus
2. efferent arteriole
3. peritubularcapillaries/vasa recta
33
What is the different in the vascular component between cortical and juxtamedullary nephrons?
C: peritubular capillaries
J: vasa recta
34
What are the 3 steps of how to make urine?
1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion (Excretion) Important to note: can occur simultaneously
35
What are the 2 structures in the renal corpuscle?
1. Glomerulus
2. Bowman's capsule
36
What are 2 characteristics of the glomerulus?
1. Tuft of capillaries
2. Surrounded by podocytes ("visceral" layer- form a barrier)
37
What is a characteristic of the Bowman's capsule?
Funnel for catching filtrate
38
Plasma enters via afferent _____ and exits via efferent ____ in the renal corpuscle.
arteriole; arteriole
39
In Glomerular filtration, there is ____ (high/low) pressure in glomerulus.
high
40
In Glomerular filtration, as blood travels through glomerulus, some plasma is pushed out into \_\_\_\_\_\_\_\_.
Bowman’s capsule
41
What is filtrate? What are 5 components?
plasma without proteins
1. Water
2. Electrolytes (eg. Na+, K+, Cl-)
3. Nutrients (glucose, amino acids)
4. Waste products (drugs, food additives)
5. Urea
42
What are the 3 layers of the glomerular membrane that the filtrate must pass through?
1. Glomerular capillary wall (epithelial cells- endothelial cells- lines vessels)
2. Basement membrane
3. Podocytefiltration slits
43
What does the Glomerular capillary wall have?
Has fenestrations (pores) ("window"- hole)
44
What does the Glomerular capillary wall allow?
Allows passage of most plasma components except large proteins and cells (eg. RBC/WBC- too large)
45
What is the base membrane?
(thin- "glad-wrap" like)
Gel-like zone
46
What are the 2 barriers of the basement membrane?
1. Physical
2. Electrical
47
What is the physical barrier of the basement membrane?
proteins can’t fit through
48
What is the electrical barrier of the basement membrane?
Negative charge repels proteins
49
Since the base membrane is acellular, what is it made up of?
Proteins
50
What are the 3 characteristics of the Podocytefiltration slits?
1. Capillaries lined with podocytes(cells with long foot processes)
2. Adjacent podocytesinterlace
3. Spaces between processes called filtration slits
51
The rate at which filtrate is produced depends on ______ forces in the renal corpuscle. What are the 2 types of forces?
opposing
1. Hydrostatic pressure (pushing force)
2. Osmotic pressure (pulling force)
52
What are 2 examples of Hydrostatic pressure (pushing force) in the renal corpuscle?
1. Glomerular capillary blood pressure
2. Bowman’s capsule hydrostatic pressure
53
What is an example of Osmotic pressure (pulling force) in the renal corpuscle?
Plasma-colloid osmotic pressure
54
What is the net filtration pressure in renal corpuscle?
balance of both forces= which one is stronger determines if filtrate is made or not, and how much Forces favouring filtration minus forces opposing filtration
55
What are 4 characteristics of Glomerular capillary blood pressure?
1. Pressure of blood inside the glomerular capillaries
2. Efferent arteriole has a smaller radius than afferent arteriole = high pressure
3. 50 mm Hg
4. **Favours** filtration (pushing pressure --\> into Bowman's capsule
56
Does Glomerular capillary blood pressure favour or oppose filtration?
Favours filtration (pushing pressure --\> into Bowman's capsule
57
What are 4 characteristics of Plasma-colloid osmotic pressure?
1. Plasma proteins suck in glomerular capillaries
2. Osmolarity is greater inside the capillaries than Bowman’s capsule
3. Pulls fluid back into capillaries
4. **Opposes** filtration
58
Does Plasma-colloid osmotic pressure favour or oppose filtration?
Oppose filtration
59
What are 2 characteristics of Bowman’s capsule hydrostatic pressure?
1. Pressure of fluid inside Bowman’s capsule
2. **Opposes** filtration
60
What is the glomerular capillary blood pressure (CBP)?
61
What is the plasma-colloid osmotic pressure (PCOP)?
62
What is the Bowman’s capsule hydrostatic pressure?
63
What is the net filtration pressure (NFP)?
64
What are the 3 factors that control glomerular filtration?
65
What is the Glomerular filtration rate (GFR)? What is the average GFR?
GFR = The amount of filtrate the kidneys produce each minute
Average: 125 ml/min
66
GFR depends on _______ pressure. Anything that alters _____ pressure will change GFR
net filtration; net filtration
67
What are Kidney stones?
Obstructs the urinary tract (eg. Ureters)
68
Which pressure will be affected by kidney stones?
Increased Bowman's capsule hydrostatic pressure
69
What effect will kidney stones have on GFR?
Decreased GFR
70
What are burns?
Damages the integumentary system –Loss of protein-rich plasma
71
Which pressure will be affected by burns?
Decreased Plasma-colloid osmotic pressure
72
What effect will burns have on GFR?
Increase GFR
73
GFR remains constant when _______ pressure fluctuates within a normal range (80-180 mm Hg)
mean arterial blood
74
The glomerulus is “protected” from changes in arterial pressure by adjusting the ______ of the afferent arteriole
diameter
75
Arteriole vasoconstriction ____ (increases/decreases) the GFR.
decrease
76
Arteriole vasodilation ____ (increases/decreases) the GFR.
increase
77
The _______ regulates glomerular capillary blood pressure
juxtaglomerular apparatus
78
What does the juxtaglomerular apparatus consist of?
modified tubular and vascular cells at the point where the distal tubule and arterioles meet
79
What is the function of the Macula densa cells?
detect changes in salt conc. in the filtrate
80
Where are the Macula densa cells found?
distal tubule
81
Paracrine signals act on \_\_\_\_\_cells (smooth muscle cells) to cause vasoconstriction or vasodilation of ____ (afferent/efferent) arteriole
granular; afferent
82
How does GFR increase and then end up decreasing?
83
What is there is a large drop in blood pressure (eg. Haemorrhage)?
The baroreceptor response causes the constriction of the afferent arteriole which decreases GFR
