Physiology 2

Question 1

What foreign compounds do the kidneys excrete

Answer 1

Drugs and their metabolites
food additives
pesticides

Question 2

What metabolic waste do the kidneys excrete

Answer 2

Urea, bilirubin and uric acid

Question 3

What is bilirubin a byproduct of

Answer 3

Haemoglobin

Question 4

What is uric acid a byproduct of

Answer 4

purine metabolism

Question 5

What is urea a byproduct of

Answer 5

protein metabolism

Question 6

Why can we never completely turn of urine production

Answer 6

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

Question 7

What does renin do

Answer 7

control the renin-angiotensin system and controls arterial blood pressure

Question 8

What do we do in response to hypoxia

Answer 8

Increase the secretion of erythropoietin to bring about more RBC production

Question 9

Why do we need calcitriol

Answer 9

To stimulate calcium absorption in the GI tract

Question 10

How is vitamin D converted into Calcitriol

Answer 10

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

Question 11

What is the primary function o the kidney

Answer 11

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

Question 12

How do we maintain homeostasis in the body

Answer 12

Input = Output

Question 13

What is the major loss of water from the body

Answer 13

Urine

Question 14

Where are the kidneys located

Answer 14

Between T12 and L3

Question 15

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

Answer 15

Peristalsis

Question 16

What does the urinary bladder act as

Answer 16

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

Question 17

What is the renal medulla made up of

Answer 17

several renal pyramids

Question 18

What appearance does the renal cortex have

Answer 18

granulated appearance

Question 19

How much do the kidneys receive of the cardiac output

Answer 19

20-25%

Question 20

What appearance does the renal medulla have

Answer 20

Striped or striated

Question 21

What is a nephron

Answer 21

The functional unit of the kidney

Question 22

How many nephrons does each kidney have

Answer 22

about 1 million

Question 23

What are the 3 functional mechanisms of the nephron

Answer 23

filtration
reabsorption
secretion

Question 24

What does the filtration form

Answer 24

the initial tubular fluid at the start of the nephron

Question 25

What does the tubular fluid lack compared to the plasma

Answer 25

The large plasma proteins and red blood cells

Question 26

Describe the vascular supply to the nephron

Answer 26

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

Question 27

Where does the blood go after passing through the peritubular capillaries

Answer 27

Renal vein

Question 28

What is the tubular component of the nephrons made up

Answer 28

single epithelial cell wall

Question 29

What happens between the glomerulus and the Bowman's capsule

Answer 29

Glomerular filtration

Question 30

What is the loop of Henle made up of

Answer 30

descending and then ascending limbs

Question 31

How can the tubular fluid be modified

Answer 31

Through reabsorption and secretion of molecules into the tubules

Question 32

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

Answer 32

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

Question 33

What are the 2 different types of nephrons in the kidney

Answer 33

Cortical (most common) | Juxtamedullary (20%)

Question 34

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

Answer 34

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

Question 35

What causes the renal medulla to have the striated appearance

Answer 35

Loads of Nephrons in particular the loop of Henles

Question 36

What do the Juxtamedullary nephrons allow us to do

Answer 36

Produce a concentrated urine

Question 37

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

Answer 37

They have more juxtamedullary nephrons than we do

Question 38

What does the concentration or relaxation in the afferent arteriole do

Answer 38

Determines how much blood will flow into the glomerular capillary

Question 39

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

Answer 39

Podocytes

Question 40

What do the foot-like processes of the podocytes do

Answer 40

They interdigitate with the neighbouring cells forming slits for filtration

Question 41

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

Answer 41

around 20%

Question 42

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

Answer 42

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

Question 43

What is formed between the podocytes and the epithelial cells

Answer 43

Basement membrane (an acellular layer)

Question 44

Where does glomerular filtration occur

Answer 44

across the glomerular membrane

Question 45

What happens in the juxtaglomerular apparatus

Answer 45

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

Question 46

What do the granular cells (modified vascular cells) do

Answer 46

The produce and secrete renin

Question 47

What are the specialised tubular cells also known as

Answer 47

Macula densa

Question 48

What does the macula densa do

Answer 48

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

Question 49

What can urine be thought of as being

Answer 49

modified filtrate of the blood

Question 50

In order to produce urine, what must the kidneys incorporate

Answer 50

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

Question 51

What renal processes occur in the production of urine

Answer 51

glomerular filtration tubular reabsorption tubular secretion

Question 52

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

Answer 52

it is not filtered and leaves through the efferent arteriole

Question 53

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

Answer 53

Rate of filtration + rate of secretion - rate of reabsorption

Question 54

What is the rate of filtration equal to

Answer 54

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

Question 55

What is GFR for a healthy adult at rest

Answer 55

125ml/min and kept relatively constant

Question 56

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

Answer 56

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

Question 57

How can we calculate the rate of excretion of a substance

Answer 57

The concentration of the substance in urine x urine flow rate

Question 58

What does the rate of excretion depend on

Answer 58

The hydration status of the body

Question 59

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

Answer 59

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

Question 60

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

Answer 60

Net secretion of that substance has occurred

Question 61

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

Answer 61

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