Lesson 28: Topic 24 - Intro to Renal Physiology

Question 1

what is the main functional unit of the kidney?

Answer 1

the nephron

Question 2

what is the kidney attached to?

Answer 2

the ureter

Question 3

where do we produce urine from?

Answer 3

the ureter, from the kidney undergoing filtration and then exits the renal pelvis and then dumps the urine into the ureter

Question 4

where do we have the renal medulla?

Answer 4

in the renal pyramid

Question 5

where is the nephron?

Answer 5

in the renal medulla

Question 6

where does filtration - reabsorption of the kidney happen?

Answer 6

in the nephron

Question 7

what is the outer layer of the kidney?

Answer 7

the renal cortex

Question 8

what is on the deeper level of the renal cortex?

Answer 8

the renal medulla

Question 9

what are the five functions of the kidney?

Answer 9

1. maintain fluid and ion homeostasis
2. waste excretion
3. drug removal
4. hormone production
5. glucose synthesis

Question 10

how does the kidney maintain fluid and ion homeostasis?

Answer 10

by:
- regulating extracellular volume and blood pressure
- osmolarity ; controlling how many solutes are being absorbed back into your blood or how much can be excreted
- ion balance
- pH (by filtering H+ ions)

Question 11

what hormones does the kidney produce?

Answer 11

• epo - erythropoietin - important for the production of red blood cells
• vitamin D activation
• renin –> angiotensin 2

Question 12

what is the total body fluid volume?

Answer 12

40L

Question 13

how much of our body fluid volume is blood?

Answer 13

5L out of the 40

Question 14

of our 5L of blood in our body, how much is plasma?

Answer 14

3L of the 5L (60%)

Question 15

what is our cardiac output per day?

Answer 15

7200L/Day

Question 16

how much of our cardiac output is given to the kidneys?

Answer 16

20% (about 1500L/day)

Question 17

what part of the blood does the kidney filter?

Answer 17

the plasma

Question 18

if our kidneys has 1500L per day of cardiac output, how much of that is plasma

Answer 18

60% of 1500 = 900L/day of plasma is going to flow in the renal system

Question 19

how much renal plasma flow is filtered by the glomerulus per day?

Answer 19

GFR = 180L/day (900 x 20%)
- only 20% of plasma is filtered

• GFR means glomerular filtration rate

Question 20

what percent of our fluid is lost as urine per day?

Answer 20

1%

Question 21

our cardiac output is about 5L/min, 20% enters the kidney. how much /min enters the kidney? how much of that is plasma?

Answer 21

about 1.041L total blood/min. 60% is plasma = 625ml plasma/min

Question 22

the glomerulus only filters 20% of the blood that enters the kidney, so how much is it filtering?

Answer 22

1.041L blood/min –> 625 ml plasma/min
20% of 625 = 125ml/min the glomerulus filters

Question 23

the 1.041L of blood enters the kidney how?

Answer 23

via the afferent arteiole

Question 24

the 80% of blood that did not get filtered (bypasses) by the glomerulus in the kidney exits the kidney how?

Answer 24

via the efferent arteriole and then goes down into the peritubular capillary and then goes back into the venous system

Question 25

what is a glomerulus?

Answer 25

it is a capillary in order to filtrate

Question 26

after the plasma is filtered by the glomerulus, where does it immediately go?

Answer 26

into the Bowmans capsule

Question 27

what is the beginning of the kidney tubule system?

Answer 27

the Bowman's capsule

Question 28

of the 20% (125mL) that enters into the kidney tubule, what percentage is reabsorbed by the peritubular capillary?

Answer 28

99% (120mL) - the 1% is excreted as urine (5mL)

Question 29

adding the reabsorbed plasma with the plasma that was not filtered, how much plasma/min is in the venous system?

Answer 29

620mL/min of the 625mL (the 5mL is excreted)

Question 30

when secretion happens, it is a very small amount. in what direction does it happen? (in the kidney)

Answer 30

from the peritubular capillary to the kidney tubule

Question 31

if cardiac output is 4L/min in a healthy child, how much plasma would be filtered by the kidneys in ml/min

Answer 31

4000mL/min x 20% of CO to the kidneys = 800mL 800mL x 60% is plasma = 480mL 480mL x 20% of plasma is filtered by glomerulus = 96 ml/min = 96 ml/min

Question 32

what is the functional unit of the kidney?

Answer 32

the nephron

Question 33

what encompasses and surrounds all of the tubule system?

Answer 33

the peritubular capillaries

Question 34

where does the peritubular capillaries drain into?

Answer 34

the venules then to the veins

Question 35

what is the tubule system immediately after the Bowman's capsule called?

Answer 35

the proximal tubule

Question 36

the proximal tubule turns into?

Answer 36

the descending loop of henle

Question 37

the descending loop of henle turns into?

Answer 37

the ascending loop of henle

Question 38

the ascending loop of henle turns into?

Answer 38

the distal tubule

Question 39

what does the distal tubule dump into?

Answer 39

the collecting duct which then excretes urine

Question 40

what is apart of the renal corpuscle?

Answer 40

- glomerulus and Bowman's capsule

Question 41

what is apart of the tubule system?

Answer 41

- proximal tubule - descending/ascending loop of henle - distal tubule - collecting duct

Question 42

what branches off of the collecting duct?

Answer 42

nephrons - many nephrons dump waste into the collecting duct

Question 43

what is the pathway of filtration through nephrons?

Answer 43

glomerulus --> bowman's space --> proximal convoluted tubule --> proximal straight tubule --> D thin Loop --> A thin Loop --> A thick Loop --> distal convoluted tubule --> cortical collecting duct --> medullary collecting duct --> renal pelvis

Question 44

which part of the collecting duct is the medullary duct?

Answer 44

the deeper, bottom section

Question 45

what is the pathway for the 80% of the plasma that bypasses the filtration?

Answer 45

renal artery --> afferent arteriole --> glomerulus --> efferent arteriole --> peritubular capillaries or Vasa Recta --> venues --> renal vein

Question 46

what is the vasa recta?

Answer 46

continuation of the efferent arteriole

Question 47

what are the two types of nephrons?

Answer 47

1. cortical 2. juxtamedullary

Question 48

** the renal corpuscle of ALL nephrons is where?

Answer 48

in the cortex region of the kidney

Question 49

where is the glomeruli in the juxtamedullary nephrons?

Answer 49

in the inner layer of cortex, closer to the medulla

Question 50

what % of nephrons are the juxtamedullary nephrons?

Answer 50

20%

Question 51

what is the size of the Henle's loop in the juxtamedullary nephrons?

Answer 51

Long Henle's loop

Question 52

true or false: the juxtamedullary nephrons produce concentrated urine?

Answer 52

true - due to the vasa recta because it is deep in the medulla

Question 53

the vasa recta is a unique structure to which nephron?

Answer 53

the juxtamedullary nephrons

Question 54

the glomerulus of the cortical nephrons sits where?

Answer 54

on the outer layer of the renal cortex

Question 55

what percentage of nephrons is cortical nephrons?

Answer 55

80%

Question 56

which nephron plays a role in respiratory and regulatory functions including water absorption. solute absorption and ion absorption?

Answer 56

the cortical nephrons

Question 57

true or false: vasa recta is a continuation of the efferent arteriole in the juxtamedullary nephrons

Answer 57

true

Question 58

true or false: blood from the afferent arteriole flows next into the peritubular capillary

Answer 58

false

Question 59

true or false: plasma enters the loop of henle from the distal tubule

Answer 59

false

Question 60

what are the three critical functions of the nephron?

Answer 60

1. glomerular filtration 2. tubular reabsorption 3. tubular secretion

Question 61

what is glomerular filtration?

Answer 61

nondiscriminant filtration of a protein-free plasma from the glomerulus into the Bowman's capsule (some proteins will not filter - like albumin)

Question 62

what is tubular reabsorption?

Answer 62

selective movement of filtered substances from the tubular lumen into the peritubular capillaries

Question 63

what is tubular secretion?

Answer 63

selective movement of nonfiltered substances from the peritubular capillaries into the tubular lumen

Question 64

what is the equation to figure out the amount of solute excreted?

Answer 64

amount filtered - amount reabsorbed + amount secreted

Question 65

can RBC, WBC or plasma proteins enter through into the glomerulus?

Answer 65

no. only plasma, water, ions and small molecules - they cannot fit through the filtration barrier (it has a certain size) therefore are just sent to venous system (good, this is why we do not urinate blood)

Question 66

the plasma that enters into the glomerulus is referred to as?

Answer 66

filtrate

Question 67

what are the structures of the glomerulus?

Answer 67

- endothelial cells - basement membrane - lumen

Question 68

the tubule and bowman's capsule is composed of?

Answer 68

epithelial cells (does not allow for good filtration - we want this, this is good)

Question 69

the glomerulus is made up of?

Answer 69

podocytes, which are separated by filtration slits which is where the filtration happens

Question 70

the movement of filtrated is through?

Answer 70

the pores between the endothelial cells, then passes through the basement membrane where it allows for endothelial cells to attach to, and then exits through the podocyte filtration slits

Question 71

the pores between the endothelial cells can be called?

Answer 71

fenestrations ( a pore, a window, an opening )