renal physiology

Question 1

eliminates an aqueous solution derived from the blood

Answer 1

urine

Question 2

regulates the composition and volume of blood and ECF by controlling water and solute excretion

Answer 2

homeostasis

Question 3

Tubular elements that eventually discharge into the environment

Answer 3

kidney

Question 4

Kidney structure

horse

Answer 4

heart shaped

Question 5

Kidney structure

cow

Answer 5

lobular

Question 6

Kidney structure

Pig, human, rodent, sheep

Answer 6

bean shaped

Question 7

Kidney cross-section

Cortex (outer region): 2

Answer 7

• Corpuscles (glomeruli/ Bowman’s capsule)

- Proximal and distal convoluted tubules

Question 8

Kidney cross-section

Medulla (inner portion): 3

Answer 8

Loop of Henle

Collecting duct

Empty into the calyx and renal pelvis

Question 9

Functional unit of the kidney

Answer 9

the nephron

Question 10

Superficial/cortical nephrons =

Answer 10

mainly in cortex, short Loop of Henle

Question 11

Juxtamedullary (JM) nephrons =

Answer 11

= long loop of Henle, extending well into the medulla

Question 12

More JM neurons =

Answer 12

better ability to concentrate urine and conserve water

Question 13

Nephron is a series of tubes that are connected to each other and eventually _______

Answer 13

provide urine a way to exit into the environment

Question 14

Parts of the nephron: 6

Answer 14

• Glomeruli
• Bowman’s capsule
• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule
• Collecting duct

Question 15

Flow of “urine” through the nephron: 9

Answer 15

glomeruli (blood that is filtered) → Bowman’s capsule → PCT → L of H → DCT → Collecting duct → calyx → renal pelvis → ureter, etc.

Question 16

Key processes of urine formation

Glomerular filtration

Answer 16

Bowman’s capsule and glomerulus

Question 17

Key processes of urine formation

Selective tubular secretion (blood → urine)

Answer 17

Proximal and distal convoluted tubule

Question 18

Key processes of urine formation

Selective tubular reabsorption (urine → blood)

Answer 18

Proximal and distal convoluted tubule

Question 19

Key processes of urine formation

Urine concentration (hyperosmotic urine) (water from urine → blood)

Answer 19

Loops of Henle, collecting tubules

Question 20

Ultrafiltration:

Answer 20

mechanism that introduces fluid into the kidney tubules; exclusion of large molecules (proteins, RBC)

Question 21

Glomerular filtration “filter” includes

Answer 21

capillary fenestrations (slits in capillary membrane),

basement membrane,

podocytes

Question 22

Glomerular filtration, Rate depends on the balance of:

Answer 22

Blood hydrostatic pressure (BP; pressure due to afferent and efferent arteriole)

Colloid osmotic pressure (COP; proteins in the blood “pull” fluid back)

Capsule fluid hydrostatic pressure (CFP; pressure by fluid already in Bowman’s Capsule)

Question 23

net pressure=

Answer 23

filtration pressure

Question 24

What is filtered?

Answer 24

Water
Ions
Glucose, amino acids
Small proteins

Question 25

Other factors affecting filtration

Answer 25

Shape of molecule- can it “fit” through the filter? Charge- positive more likely to be filtered than negative

Question 26

Tubular reabsorption

Answer 26

substances returned to the blood from the “urine”

Question 27

Tubular secretion

Answer 27

substances from the blood added to the urine for excretion

Question 28

Proximal convoluted tubules

Answer 28

Primary site of reabsorption/secretion- at least 60% reabsorbed

Question 29

Proximal convoluted tubules Absorption of:

Answer 29

``` Glucose Amino acids NaCl HCO3- K+ H2O ```

Question 30

Proximal convoluted tubules Secretion of:

Answer 30

H+ Ammonia Organic compounds (drugs)

Question 31

The majority of solute and water reabsorption occurs in the ____

Answer 31

Proximal convoluted tubules

Question 32

Solutes and water must cross several layers to get from tubule to capillary what are they? 3

Answer 32

Tubular epithelial cell: apical membrane (urine side) Tubular epithelial cell: basolateral membrane (blood side) Capillary endothelium (interstitial fluid and capillary exchange quite freely)

Question 33

Involved in creating hypertonic urine

Answer 33

Loop of Henle

Question 34

Fluid leaving the L of H is very ____

Answer 34

dilute

Question 35

Site of hormonal regulation of water and Na+ reabsorption

Answer 35

Distal convoluted tubules

Question 36

Distal convoluted tubules ADH:

Answer 36

increases water reabsorption via aquaporins ↑ ADH = ↑ aquaporins in the DCT and collecting ducts (luminal/apical side) = ↑ H2O from the urine into the blood stream (concentrated urine)

Question 37

Distal convoluted tubules Aldosterone:

Answer 37

: increases Na+ reabsorption and K+ secretion Increases expression of transport proteins on basolateral membrane (Na+, K+-ATPase) and channels on apical membrane (K+ and Na+) Active transport of Na+ back into the blood, K+ into the urine

Question 38

Distal convoluted tubules Parathyroid hormone and Vitamin D

Answer 38

Increase calcium reabsorption by increasing Ca2+ channels on apical membrane

Question 39

Distal convoluted tubules Role in acid-base balance

Answer 39

H+ secretion, HCO3- reabsorption

Question 40

Organs of water regulation In mammals and birds =

Answer 40

kidney

Question 41

Capable of regulating how much water is lost from the body

Answer 41

kidney

Question 42

U/P = 1

Answer 42

urine and plasma are isosmotic

Question 43

U/P > 1

Answer 43

urine is more concentrated in solutes than plasma (hyperosmotic)- water conservation

Question 44

U/P < 1

Answer 44

urine is more dilute in solutes than plasma (hyposmotic)- water loss

Question 45

Only some species have the ability to produce hyperosmotic urine

Answer 45

U/P > 1 Mammals, birds, insects

Question 46

Urine concentration occurs in the ______ _______ and requires the processes of the _________

Answer 46

collecting duct Loop of Henle

Question 47

Hairpin loop configuration, with different permeabilities in the ascending and descending loops, allows for the establishment of a gradient: descending

Answer 47

Descending: permeable to water; water enters the interstitial fluid (and blood) from the urine -Urine and medulla become more concentrated (increased Osm) as you go deeper in the medulla

Question 48

Hairpin loop configuration, with different permeabilities in the ascending and descending loops, allows for the establishment of a gradient: ascending

Answer 48

Ascending: active transport of Na+ into the interstitial fluid (and blood) from the urine; impermeable to water -Urine and medulla become less concentrated (lower Osm) as you move towards the cortex

Question 49

Avian kidney Urine

Answer 49

exits the colada

Question 50

No Loop of Henle

Answer 50

Avian kidney

Question 51

Cannot produce hyperosmotic urine

Answer 51

Avian kidney