Physiology

Question 1

Podocytes - location

Answer 1

Make up the inner layer of the bowman capsule

Question 2

Podocytes - definition

Answer 2

Feet like extensions which extend out from the cell body. These extensions wrap around the capillaries and form a barrier of the capillary wall

Question 3

Podocytes - function

Answer 3

Act as a barrier of the capillary wall

Question 4

Mesangial cells

Answer 4

Contractile cells which keep the glomerulus clean and keep it together physically
Provides support to capillaries

Question 5

Vasa recta (peri-tubular capillaries)- definition

Answer 5

Loops of thin walled blood vessels that arise from the efferent arteriole
They look like hairpins as they descend from the cortex -> medulla

Question 6

Vasa recta capillaries are freely permeable to salt and water. True or false?

Answer 6

True

Question 7

Vasa recta - location

Answer 7

Run alongside the loop of henle of the juxtamedullary nephrons

Question 8

GFR

Answer 8

The rate at which protein-free plasma is filtered from the glomeruli -> bowman capsule per unit time

Question 9

What is the major determinant of GR?

Answer 9

Blood pressure

Question 10

Extrinsic regulation of GFR

Answer 10

Baroreceptor reflex

Question 11

Extrinsic control can over-ride intrinsic control. True or false?

Answer 11

True

Question 12

Increased arterial blood pressure INCREASES/DECREASES the GFR

Answer 12

Increases (due to vasodilation)

Question 13

Decreased arterial blood pressure INCREASES/DECREASES the GFR?

Answer 13

Decreases (due to vasoconstriction)

Question 14

What is used clinically to measure plasma renal flow?

Answer 14

Para-amino hippuric acid (PAH)

Question 15

ADH - function

Answer 15

Stimulates renal tubular cells to increase water reabsorption.
Changes expression of aquaporins at the distal tubule and collecting duct

Question 16

What are aquaporins?

Answer 16

Water channels

Question 17

High ADH levels means LOTS/FEW aquaporin expression?

Answer 17

LOTS of

Question 18

Low ADH levels means LOTS/FEW aquaporin expression?

Answer 18

FEW

Question 19

ADH has influence over water AND salt reabsorption. True or False?

Answer 19

False

- water reabsorption only

Question 20

ADH role in the dehydrated state?

Answer 20

Dehydrated -> increased plasma osmolarity -> increased ADH secretion -> lots of aquaporins expressed -> distal tubule more permeable to water reabsorption

Question 21

In the dehydrated state, patients have a LARGE/SMALL volume of CONCENTRATED/DILUTE urine?

Answer 21

Small

Concentrated

Question 22

ADH role in the over hydrated state?

Answer 22

Decreased plasma osmolarity -> decreased ADH secretion -> no aquaporins expressed -> distal tubular cells are impermeable to water -> no water reabsorption

Question 23

In the over-hydrated state, patients have a LARGE/SMALL volume of CONCENTRATED/DILUTE urine?

Answer 23

Large

Dilute

Question 24

Nicotine STIMULATES/INHIBITS ADH release?

Answer 24

Stimulates

Question 25

Alcohol STIMULATES/INHIBITS ADH release?

Answer 25

Inhibits

Question 26

What is the overall function of aldosterone release?

Answer 26

To increase arterial BP

Question 27

Increased aldosterone means INCREASED/DECREASED Na reabsorption?

Answer 27

Increased

Question 28

Increased aldosterone means INCREASED/DECREASED K+ reabsorption

Answer 28

Decreased | - therefore, increased K+ secretion in the urine

Question 29

When is aldosterone secreted? (state 3 reasons)

Answer 29

When there is a rising plasma conc of K+ When there is a fall in Na+ plasma conc When RAAS is activated

Question 30

What is Anti Natriuretic Peptide (ANP) ?

Answer 30

Peptide hormone produced by the heart and stored in atrial muscle cells

Question 31

When is ANP released?

Answer 31

When atrial muscle cells are stretched 9due to circulating plasma volume)

Question 32

ANP function?

Answer 32

Decrease plasma volume and lowers BP

Question 33

What are the 2 mechanisms involved in the process of bladder emptying?

Answer 33

Micturation reflex | Voluntary control

Question 34

Micturation reflex

Answer 34

Involuntary emptying of the bladder by simultaneous contraction and opening of both the internal and external urethral sphincters

Question 35

Voluntary control - urine excretion

Answer 35

Over-riding the micturition reflex through voluntary control until there is a convenient time and place to excrete urine There is deliberate tightening of the external urethral sphincter and surrounding diaphragm