W9 Renal Physiology

Question 1

Where are the kidneys located

Answer 1

one on either side of the spine located in the posterior wall of the abdominal cavity just below the rib cage

Question 2

why is the right kidney slightly lower than the left because of the position of the liver

Answer 2

due to the position of the liver

Question 3

what is the average weight of an adult human kidney

Answer 3

120 - 140g

Question 4

what flows in the renal artery

Answer 4

nutrients such as

• Na+
• K
• Amino acids
• Glucose

Oxygen

Waste such as
- Urea

Question 5

what is the vasa recta

Answer 5

the capillary networks that supply blood to the medulla

Question 6

what are peritubular capillaries

Answer 6

tiny blood vessels in your kidneys. They deliver wastes to be secreted into urine (pee). They also reabsorb nutrients your body needs. Peritubular capillaries play an essential role in your urinary system.

Question 7

how much of the cardiac output do the kidneys recieve

Answer 7

25%

Question 8

how much plasma on average do the kidneys filter in a 70kg human

Answer 8

120 litres

Question 9

Label a kidney

Answer 9

slide 1

Question 10

what are the three main parts of the nephron

Answer 10

renal corpuscle
renal tobule
capillary network

Question 11

label a nephron

Answer 11

label a nephron

Question 12

where do the peritubular capillaries surround

Answer 12

they surround the proximal and distal convoluted tubules

Question 13

what does the vasa recta surround

Answer 13

the loop of henle

Question 14

what are the three main processes that take place in the nephron

Answer 14

ultra filtration
reabsorption
secretion

Question 15

Where does ultra filtration take place

Answer 15

occurs in the glomerulus & bowmans capsule

Question 16

how does ultra filtration take place

Answer 16

blood enters the glomerulus under a high pressure due to the size difference in the lumen of afferent and efferent arteriole at either end of the glomerulus

the constituents from the blood leave the glomerulus and enter the nephron which forms the filtrate.

Question 17

what is filtration dependent on

Answer 17

filtration is determined on the size of the molecule for example small molecules such as water and have a molecular mass of up to 5000 flow freely however larger molecules such as albumin with 69,000 mw are less likely to move across

Question 18

what is reabsorption

Answer 18

movement of constituents from the tubular fluid back into the blood to stop the constituents from being excreted.

Question 19

what is reabsorption aided by

Answer 19

vasa recta + peritubular capillaries

Question 20

what is transcellular and paracellular mean

Answer 20

Transcellular transport involves the transportation of solutes by a cell through a cell

Paracellular transport refers to the transfer of substances across an epithelium by passing through the intercellular space between the cells.

Question 21

in what form of transport does reabsorption rely on

Answer 21

both paracellular + transcellular

Question 22

what is secretion

Answer 22

movement of constituents from the blood into the tubular fluid so that they are excreted in the urine

Question 23

what is the easiest way to remember the difference between secretion and reabsorption

Answer 23

reabsorption is removing stuff from final product of urine

secretion adds to final product of the urine

Question 24

what form of transport does secretion rely upon

Answer 24

both paracellular + transcellular

Question 25

what are the 4 main roles of the kidney

Answer 25

homeostasis produce an active form of vitamin D that promotes strong and healthy bones control the production of red blood cells remove drugs from the body

Question 26

how is the kidney involved in homeostasis

Answer 26

removing waste products from the body regulating the pH of your blood and blood pressure by regulating inorganic ions regulating water balance to maintain osmolality releasing hormones that influence water balance and regulate blood pressure

Question 27

what is the main component of urine

Answer 27

urea

Question 28

what is contained in the urine

Answer 28

urea uric acid creatinine

Question 29

what is completely reabsorbed by the body

Answer 29

protein and glucose

Question 30

how much Na+ is reabsorbed

Answer 30

60-70%

Question 31

how much HCO3- is reabsorbed

Answer 31

90%

Question 32

where is Na+ and HCO3- reabsorbed

Answer 32

proximal convoluted tubule

Question 33

is the descending limb of the loop of henle impermeable to ions

Answer 33

yes

Question 34

what does the ascending limb contain

Answer 34

Na/K pumps Na/K/Cl transporters

Question 35

what does the containment of pumps and transporters in the asscending limb mean

Answer 35

Na, Cl and K ions leave the tubular fluid via the vasa recta

Question 36

where does the reabsorption of water take place

Answer 36

tubules of the nephrons

Question 37

what are the two ways in which we can reabsorb water

Answer 37

along an osmotic gradient (passive) by the release of hormones from the kidneys (active)

Question 38

what is the general relationship with sodium and water

Answer 38

wherever sodium goes water follows

Question 39

where is the majority of the water absorbed

Answer 39

proximal convoluted tubule as this is where 60-70% of the sodium is reabsorbed

Question 40

what hormones does the kidney release to regulate blood pressure

Answer 40

anti diuretic hormone it is also involved in the renin angiotensin aldosterone system

Question 41

what cell is involved in the release of renin

Answer 41

juxtaglomerular cells

Question 42

when do they release renin

Answer 42

when we have a low blood pressure sympathetic nerves low sodium levels picked up by the mascular densa cells

Question 43

what are the mascular densa cells

Answer 43

Macula densa (MD) cells are chief cells within the kidney, playing key sensory and regulatory functions in the maintenance of body fluid, electrolyte homeostasis, and blood pressure.

Question 44

what is a chief cell

Answer 44

chief cells (zymogenic) are basophilic cells that are located in the bottom of the gland and which produce different gastric enzyme precursors

Question 45

describe the affects of rennin

Answer 45

liver produces angiotensinogen which is inactive renin combines with this to produce angiotensin 1 endothelial cells produce angiotensin converting enzyme (ACE) ACE combines with angiotensin 1 to produce angiotensin 2

Question 46

what does angiotensin 2 target

Answer 46

smooth muscle cells causing increased resistance in the form of vasoconstriction increasing blood pressure kidneys as it signal them to reabsorb more Na+ and therefor more water pituatary gland signaling for the release of anti diuretic hormone (ADH) Adrenal gland signalling to release aldosterone

Question 47

where is ADH released from

Answer 47

pituitary gland

Question 48

what is the goal of ADH

Answer 48

reabsorption of water

Question 49

what is release of ADH triggered by

Answer 49

angiotensin 2 (Renin angiotensin aldesterone system) osmoreceptors if there is a higher concentration of blood low blood volume: the sympathetic nerve ending in the veins of the heart will sense this low blood pressure: sympathetic nerve endings in the arteries of the heart will sense this

Question 50

what is a condition that can cause ADH to not work correctly

Answer 50

diabetes insipidus - kidneys are unable to conserve water making pale watery urine at an increased rate of urination (15-20 mins) increased thirst, always feeling dry

Question 51

what are the two types of diabetes insipidus

Answer 51

cranial diabetes insipidus nephrogenic diabetes isnipidus

Question 52

what can cause cranial diabetes insipidus

Answer 52

brain trauma damaging hypothalamus or pituitary gland severe head injury damaging hypothalamus or pituitary gland complications that occur during brain or pituitary gland surgery

Question 53

what are the causes of nephrogenic diabetes insipidus

Answer 53

nephrons unable to respond to ADH genetic acquire from use of longterm lithium for bipolar disease or other causes such as hypercalcaemia or obstruction of the ureters