The kidneys – anatomy and normal physiology

Question 1

Where are the kidneys located?

Answer 1

Retroperitoneally at the level of the lower ribs

Question 2

What major vessels do the kidneys extend from?

Answer 2

Inferior vena cava
Aorta

Question 3

Where are adrenal galnds located?

Answer 3

On the superior end of each kidney

Question 4

What structure connects each kidney to the bladder?

Answer 4

Ureter

Question 5

How is the kidney divided?

Answer 5

Into an outer cortex and an inner medulla

Question 6

Where does urine go after leaving the nephrons?

Answer 6

Into the renal pelvis, then through the urter into the bladder

Question 7

What is the functional unit of each kidney?

Answer 7

The nephron

Question 8

How many nephron are in each kidney?

Answer 8

Millions

Question 9

What are nephrons composed of?

Answer 9

Small tubules and associated blood vessels

Question 10

Where are nephrons loacated?

Answer 10

Within the medulla of the kidney

Question 11

How is filtrate modified?

Answer 11

By transport to and from the tubule lumen

Question 12

What leaves via the collecting ducts?

Answer 12

Urine

Question 13

Where does filtration occur in the nephron?

Answer 13

At the renal corpuscle

Question 14

How much filtrate is produced per day?

Answer 14

180 L/day

Question 15

How much filtrate is reabsorbed by teh proximal tubule?

Answer 15

About 70% (54 L/day remains)

Question 16

What happens in the loop of Henle?

Answer 16

More solute is reabsorbed than water, making the filtrate dilute (100 mOsm)

Question 17

How much filtrate remains at the end?

Answer 17

1.5 L/day with 100-1200 mOsm depending on hydration

Question 18

What is the equation for amount excretion?

Answer 18

Excreted = filtration - reabsorbed + secreted

Question 19

What are the main functions the kidney?

Answer 19

Filtration
Reabsorption
Seccretion
Excretion

Question 20

What is filtrate?

Answer 20

Fluid filtered from blood into the nephron

Question 21

Where does reabsorption occur?

Answer 21

In the peritubular capillaries

Question 22

What is secretion?

Answer 22

Movement of materials from blood into the tubule

Question 23

What perceent of plasma is filtered in the glomerulus?

Answer 23

20%

Question 24

How much filtered fluid is excreted?

Answer 24

Less than 1%

Question 25

What are the 3 filtration barriers?

Answer 25

Capillary endothelium Basement membrane Podocytes

Question 26

What influences Glomerular Filtration Rate (GFR)?

Answer 26

Net filtration pressure and filtration coefficient

Question 27

How is GFR regulated?

Answer 27

Primarily by renal arterile blood flow

Question 28

What detects NaCl in the nephron?

Answer 28

Macula densa cells

Question 29

What do granular cells secrete?

Answer 29

Renin

Question 30

What makes up the juxtaglomerular apparatus?

Answer 30

Macula densa and granular cells

Question 31

What does paracrine signaling between nephron and arteriole do?

Answer 31

Influences GFR

Question 32

What are the two type of transport in reabsorption?

Answer 32

Transepithelial (transcellular) Paracellular

Question 33

How is sodium reabsorbed?

Answer 33

Actively, through trasnporters

Question 34

WHat follows sodium passively?

Answer 34

Water and urea

Question 35

How are proteins reabsorbed?

Answer 35

By receptor-mediated endocytosis

Question 36

How is glucose trasnported into cells?

Answer 36

Via SGLT (Sodium-glucose co-transporter)

Question 37

How does glucose exit cells?

Answer 37

Via GULT (Facilitated diffusion)

Question 38

What poers sodium trasnport?

Answer 38

Na+/K+ ATPase pump

Question 39

What is transported maximum (Tm)?

Answer 39

The rate when all transporters are saturated

Question 40

What is the renal threshold?

Answer 40

Plasma concentration when saturation begins

Question 41

What happens to glucose above the renal threshold?

Answer 41

It appears in the urine (excretion begins)

Question 42

What is reabsorbed in the proximal convoluted tubule (PCT) ?

Answer 42

65% of Na+ and most other solutes

Question 43

How does pressure affect reabsorption?

Answer 43

Low hydrostatic pressure in peritubular capillaries favours reabsorption

Question 44

When is osmolarity highest?

Answer 44

Deep in the renal medulla

Question 45

What reabsorbs only water?

Answer 45

Descending limb of the loop of Henle

Question 46

What reabsorbs solutes but not water?

Answer 46

Thick ascending limb

Question 47

What maintains medullary osmotic gradient?

Answer 47

Contercurrent exchange in vasa recta

Question 48

Why is ascending limb impermeable to water?

Answer 48

To create dilute filtrate and allow salt reabsorption

Question 49

What moleucles are secreted?

Answer 49

K+ H+ Organic anions

Question 50

What transporter is involved in secretion?

Answer 50

Organic Anion Transporter (OAT)

Question 51

What type of transporter does secretion involve?

Answer 51

Tertiary active transport

Question 52

What is clearance?

Answer 52

Rate a solute disappears from plasma

Question 53

What substance is used to measure GFR?

Answer 53

Isulin

Question 54

What is glucose celarence normally?

Answer 54

0 (fully absorbed)

Question 55

What is penicillin clearence like?

Answer 55

Net secretion

Question 56

What is micturition?

Answer 56

The process of urination

Question 57

Where is urine stored?

Answer 57

In the bladder

Question 58

What controls urine flow from the bladder?

Answer 58

Internal and external sphincters

Question 59

What initiates bladder contraction?

Answer 59

Parasympathertic signals from spinal reflexes

Question 60

Can micturition be controlled voluntarily?

Answer 60

Yes, by brainsetm and cortex override