Physiology 2 Flashcards Preview

SM Renal > Physiology 2 > Flashcards

Flashcards in Physiology 2 Deck (61):
1

What foreign compounds do the kidneys excrete

Drugs and their metabolites
food additives
pesticides

2

What metabolic waste do the kidneys excrete

Urea, bilirubin and uric acid

3

What is bilirubin a byproduct of

Haemoglobin

4

What is uric acid a byproduct of

purine metabolism

5

What is urea a byproduct of

protein metabolism

6

Why can we never completely turn of urine production

we have to get rid of some metabolic wastes in the solution

7

What does renin do

control the renin-angiotensin system and controls arterial blood pressure

8

What do we do in response to hypoxia

Increase the secretion of erythropoietin to bring about more RBC production

9

Why do we need calcitriol

To stimulate calcium absorption in the GI tract

10

How is vitamin D converted into Calcitriol

The OH group added by either the liver or by cells in the kidney

11

What is the primary function o the kidney

to regulate the volume, composition and osmolarity of the body fluids

12

How do we maintain homeostasis in the body

Input = Output

13

What is the major loss of water from the body

Urine

14

Where are the kidneys located

Between T12 and L3

15

What helps the smooth muscle of the ureter to propel urine for the kidney down to the bladder

Peristalsis

16

What does the urinary bladder act as

A temporary store vessel for urine until there is an appropriate time to expel the urine

17

What is the renal medulla made up of

several renal pyramids

18

What appearance does the renal cortex have

granulated appearance

19

How much do the kidneys receive of the cardiac output

20-25%

20

What appearance does the renal medulla have

Striped or striated

21

What is a nephron

The functional unit of the kidney

22

How many nephrons does each kidney have

about 1 million

23

What are the 3 functional mechanisms of the nephron

filtration
reabsorption
secretion

24

What does the filtration form

the initial tubular fluid at the start of the nephron

25

What does the tubular fluid lack compared to the plasma

The large plasma proteins and red blood cells

26

Describe the vascular supply to the nephron

Initially an afferent arteriole which subdivides into a glomerulus (tuft) which then drains back into an efferent arteriole
Unique to anywhere else in the body

27

Where does the blood go after passing through the peritubular capillaries

Renal vein

28

What is the tubular component of the nephrons made up

single epithelial cell wall

29

What happens between the glomerulus and the Bowman's capsule

Glomerular filtration

30

What is the loop of Henle made up of

descending and then ascending limbs

31

How can the tubular fluid be modified

Through reabsorption and secretion of molecules into the tubules

32

What happens when the tubular fluid leaves the collecting duct and why

It is then called urine and no further modification can occur here

33

What are the 2 different types of nephrons in the kidney

Cortical (most common)
Juxtamedullary (20%)

34

What are the 2 main differences between the Cortical and juxtamedullary nephrons

Juxtamedullary have a very long loop of Henle
and they have a single network of capillaries (Vasa recta) whereas the cortical nephron have peritubular capillaries

35

What causes the renal medulla to have the striated appearance

Loads of Nephrons in particular the loop of Henles

36

What do the Juxtamedullary nephrons allow us to do

Produce a concentrated urine

37

Why is the desert rat able to produce more concentrated urine than us as humans

They have more juxtamedullary nephrons than we do

38

What does the concentration or relaxation in the afferent arteriole do

Determines how much blood will flow into the glomerular capillary

39

What cells make up the inner layer of the Bowman's capsule

Podocytes

40

What do the foot-like processes of the podocytes do

They interdigitate with the neighbouring cells forming slits for filtration

41

How much of the plasma that flows through the capillaries ends up forming the tubular fluid

around 20%

42

What is the difference in composition of the tubular fluid and the plasma

Tubular fluid is identical other than lacking large plasma protein and RBCs

43

What is formed between the podocytes and the epithelial cells

Basement membrane (an acellular layer)

44

Where does glomerular filtration occur

across the glomerular membrane

45

What happens in the juxtaglomerular apparatus

The distal tubule passes through the fork that is formed between the afferent and efferent arterioles

46

What do the granular cells (modified vascular cells) do

The produce and secrete renin

47

What are the specialised tubular cells also known as

Macula densa

48

What does the macula densa do

they sense the amount of salt in the tubular fluid as it passes through the region of the nephron

49

What can urine be thought of as being

modified filtrate of the blood

50

In order to produce urine, what must the kidneys incorporate

filtration system
rich blood supply
mechanisms for urine modification (tubular reabsorption and secretion)

51

What renal processes occur in the production of urine

glomerular filtration
tubular reabsorption
tubular secretion

52

What happens to the majority of the plasma that enters the glomerulus ?

it is not filtered and leaves through the efferent arteriole

53

How can we calculate the rate of excretion of a particular substance

Rate of filtration + rate of secretion - rate of reabsorption

54

What is the rate of filtration equal to

The concentration of the substance in the plasma x Glomerular filtration rate

55

What is GFR for a healthy adult at rest

125ml/min and kept relatively constant

56

What happens if we increase the concentration of the substance in the plasma

The rate at which the kidneys filter the substance will increase as GFR is constant

57

How can we calculate the rate of excretion of a substance

The concentration of the substance in urine x urine flow rate

58

What does the rate of excretion depend on

The hydration status of the body

59

What happens if the rate of filtration is greater than the rate of excretion

The kidneys are filtering more than what is being excreted - more reabsorption

60

If the rate of filtration is less than the rate of excretion, what has happened to the net secretion

Net secretion of that substance has occurred

61

What is important to do to the GFR when calculating the rate of filtration

convert it from ml/min to litres / min so that the units are consistent