PHYSIOLOGY

Question 1

What are the two types of nephrons in the kidney?

Answer 1

Cortical (85%)

Juxtamedullary (15%)

Question 2

What is the function of vasa recta

Answer 2

concentration/dilution of urine
nutreints/oxygen to nephrons
secretiom

Question 3

List the arteries starting from renal that blood passes through to get to the Bowman’s capsule?

Answer 3

Renal=> segmental=> Interlobar=> Arcute=> Interlobular => affarent

Question 4

What is known by term Ultrafiltration

Answer 4

passive movement of plasma ultrafiltrate from glomerular capillaries into Bowman’s capsule

Question 5

if two dextrins of the same size were to cross a membrane one being mostly +vely charged (cation) and the other negatively charged (anion) which one would cross more easily and why ?

Answer 5

anion=> the basement membrane and endothelial cells are negatively charged and so they repel anions and attract cations.
Note: podocytes differentiate based on size only

Question 6

what is a response of SMC to change in pressure of affarent arterioles

Answer 6

decreased pressure= relax

increased pressure = construct

Question 7

How is the increase in GFR detected

Answer 7

More Na in DCT=> macula densa stimulated

Question 8

What are the local mediators that can alter flow in affarent arteries

Answer 8

adenosisn => vasoconstriction

prostaglandins=> vasodilation

Question 9

What is a threshold for glucose reabsorption?

Answer 9

200mg/ 100ml

Question 10

What precentages of various substances are reabsorbed in PCT

Answer 10

• 100% filtered nutrients
• 65% filtered water
• 80-90% filtered HCO3-
• 60% filtered Cl-
• 67% filtered Na+
• 65% filtered K+

Question 11

Give some examples of secreted anions (Kidney)

Answer 11

bile salts, fatty acids, penicilin, NSAI

Question 12

Give some examples of secreted cations (Kidney)

Answer 12

dopamin, histamin, seratonin, Morphine , atropine

Question 13

What are the properties of peritubular capilaries that allow substance reabsorption

Answer 13

high oncotic pressure

low water and electrolyte continence (also hydrostatic and oncotic pressure in the intestitial fluid)

Question 14

Give a definition of glomerular filtration rate

Answer 14

amount of filtrate that is produced from the blood flowing through the glomerulus per unit time

Question 15

what is the equation for filtration fraction

Answer 15

GFR/RPF (vol of blood without RBC)

Question 16

Define clearance rate

Answer 16

• The volume of plasma from which the substance is completely removed by the kidney per unit time

Question 17

Give an equation for clearance rate

Answer 17

(urine con. x urine flow)/plasma con

Question 18

Why is creatin used to asses GFR

Answer 18

completely cleared hence GFR=CR

Question 19

What is an ideal substance for measuring of GFR

Answer 19

• Freely filtered across the glomerulus
• Not reabsorbed or secreted
• Not metabolised

Question 20

What moleculs are transported by NAN dependent transport in PCT

Answer 20

AA, Carboxilic acid, Phosphate, Lactate, glucose, Hydrogen (out)
Cl distally (trans and paracellular)

Question 21

What are the bases of movement in thin descending limb

Answer 21

oncotic pressure of the intestitium (vertually no transporters)

Question 22

What are the key transporters in the thick ascending limb

Answer 22

APICAL
NAKCC2=> (NA, K and 2 Cl in )
ROMKA => K out
Basolateral
Na/K ATPase => 3Na out, 2K in 
Cl channel => Cl out

Question 23

where is the Na/K ATPase located

Answer 23

Basolateral membrane

Question 24

What are the key transporters in the DCT

Answer 24

Na/Cl co-transporter and Ca channel apically
Basolateral:
Cl channe, NCX(Na in Ca out)

Question 25

What are the two types of cell in theCD

Answer 25

principal (70%) and intercalated (30%)

Question 26

What are the principlechannels of Principal cells

Answer 26

ENaC (Na in) K out Aquapoirin 2 (ADH depdendent)stimulated

Question 27

What are the functions of atrial nutriuretic peptide?

Answer 27

increased GFR=> vasodialtion of affarent arterioles increasedvasa recta flow => reduction in gradient of medulla decreased Na reabsorption in CD and DCT inhibition of renin secretion

Question 28

How is release of atrial natruretic peptide

Answer 28

Reelased in response of atrial stretch (large end diastolic volume)

Question 29

What is the role of sympathetic nervous sytem on kidney

Answer 29

vasoconstriction of renal arteries induction of Na/H excxhanger(PCT) increasein renin

Question 30

What factor stimulate renin release

Answer 30

SNS, high Na or CL in DCT (macula densa detection)

Question 31

Where is renin released and why is it important

Answer 31

Granular cells of jaxtoglomerularapparatus | key regulation of Angiotensin 2 pathway

Question 32

What isthe ffect of angiotenisn 2

Answer 32

``` vasoconstriction of arteries Aldosteron release SNS activation ADH release Nareqabsorption through Na/H exchanger ```

Question 33

what isthefunction of aldosteron

Answer 33

increased na reabsorption and K seceretion through transcriptional regulation

Question 34

Why is prostaglandin and bradykinin important in the kidney

Answer 34

vasodilators that act agains vasocconstriction

Question 35

What is an extra effect of ACE

Answer 35

break down of bradykinin

Question 36

What are three causes of secondary hypertension related to adrenal glands

Answer 36

Conn's (aldosteron secreting adenoma) Cushion's Pheochromocytoma (na and NA and adrenalin secretion=> CO)

Question 37

What is the location of osmoreceptors? What do they stimulate

Answer 37

supraoptic and paraventricular nuclei thirst 10% dehydration ADH 1% dehydration

Question 38

What sort of hormon is ADH and where is it synthesised and relased

Answer 38

peptide S: supraoptic nucleus of hypothalamus R: posterior pituitary

Question 39

What arethe actions of ADH

Answer 39

increased water reabsorption (aquaporin 2) | vasoconstriction

Question 40

What is meant by diaresis

Answer 40

hypo-osmotic urine

Question 41

What is corticopupillary osmotic gradient and how is it maintained

Answer 41

gradient formed by blood flow that is opposit to filtrate flow in the vasa recta. maintains the osmotic gradient i.e. intestitium always hyperosmotic

Question 42

Why is countercarrent of vasa recta important?

Answer 42

it maintains the concentration gradient down the medulla i.e. initially blood hypo-osmotic taking up irons from thick ascending limb then as it progresses back up the blood is hyperosmotic allowing absorption of water

Question 43

Where in the kidney is calcium reabsorbed and in what proportions

Answer 43

PCT 66% Loop of henly 24% DCT/CD 10% (regulated)

Question 44

What is the name of crystals formed in the bones

Answer 44

hydroxyapetite

Question 45

Where most of absorption of alkaline phosphate occurs

Answer 45

PCT => 95%

Question 46

What factors increase excretion of alkaline phosphate

Answer 46

PTH, acidosis, glucocorticosteroids

Question 47

What part of nephron is important in potassium regulation and why? how is it controlles?

Answer 47

Principal cells of DCT and CD secret K+ (15-120%=> {} dependent) controlled by aldosteron that increases expression of K+ channel K+/NA+ ATPase and ENaC

Question 48

whatis the relationshipbetween Na and K balance

Answer 48

reabsorption of Na leads to loss of K

Question 49

What channel is used in reabsorption of K in intercalated cells

Answer 49

H/K ATPase

Question 50

How is normal ECf K plas maintained forllowing a meal

Answer 50

Shift of K into ICF followin insulin and catechalamines relase tha both increase activity of K/NA ATPase as well as increased excretion of K in the kidney

Question 51

Whatfactors increase ECF [K]

Answer 51

cell lysis, post exercies, acidosis, plasma hyperosmolarity