MCQ 4 - Renal System

Question 1

Components of urinary system

Answer 1

2 Kidneys = produces urine
Ureter = transports urine to urinary bladder
Urinary bladder = stores urine prior elimination - process called urination
Urethra = conducts urine to exterior (semen too in males)

Question 2

3 Major functions of urinary system

Answer 2

Excretion = removes organic waste from body fluids
Elimination = discharge of waste products to environment
Homeostatic regulation = of volume + solute concentration of blood

Question 3

Location and position of the kidney

Answer 3

Either side of vertebral column (T12 + L3)
Against dorsal abdominal wall
Right kidney lower (left superior to right) (right inferior to left)
Adrenals on upper surface - on superior surface
Embedded in fat

Question 4

5 main homeostatic functions in urinary system

Answer 4

Regulate blood volume + pressure = adjust water loss in urine, release erythropoietin + renin

Regulate plasma conc. (Na, K, Cl ions) = lost via urine, Ca ions controlled in kidneys via calcitriol synthesis

Stabilise blood pH = control loss of H + bicarbonate ions in urine

Conserve valuable nutrients

Assist liver = detoxifying poisons

Question 5

2 functional layers of kidney

Answer 5

Cortex

Medulla

Question 6

Name of lobed structures in kidney

Answer 6

Medullary pyramids

Question 7

What is hilum

Answer 7

Central fissure where - renal artery/vein, lymphatics, nerves, ureter enter and leave

Question 8

What is the renal calyces

Answer 8

Joining to form renal pelvis where urine empties

Question 9

Waste excretion

3 main parts

Answer 9

Filtration = filters serum (including waste, toxins, nutrients, ions, water)
Reabsorption = selectively absorbs needed substances
Secretion = secretes unwanted substances

Question 10

What is urine

Answer 10

Nitrogenous by-product from protein metabolism = urea, uric acid, creatine, broken down haemoglobin, urobilin gives colour, toxins, drugs, waste

Question 11

What is the blood supply to the kidney?

How does it enter/leave?

Answer 11

25% of cardiac output through kidney
Blood is filtered approximately 60 times a day

Blood enters via renal artery
Clean blood leaves via renal vein (waste out via ureter)

Question 12

Structure of renal artery

Answer 12

Segmented arteries then to…

Interlobar arteries between renal pyramids

Question 13

Structure of nephron (in order)

Answer 13

Renal corpuscle (glomerulus + bowmans capsule) = FILTRATION
Proximal convoluted tubule = REABSORPTION/SECRETION 
Loop of Henle = REABSORPTION 
Distal convoluted tubule = REABSORPTION/SECRETION 
Collecting duct = REABSORPTION

Question 14

Divide nephron structure into 2 functional layers (cortex + medulla)

Answer 14

Cortex = glomerulus + convoluted tubule (distal + proximal)

Medulla = loop of Henle, collecting duct + tubular capillaries

Question 15

How is the kidney kept into position

Answer 15

Fibrous capsule = layer of collagen fibres covering outer surface of entire organ

Perinephric fat = thick layer of adipose tissue, surrounding fibrous capsule

Renal fascia = dense, fibrous outer layer, anchors kidney to structures around it

Question 16

Renal pyramids

Answer 16

In renal medulla 
6-18 
Distinct triangular structures
Base of pyramid touches cortex 
Tip of pyramid (renal papilla) projects into renal sinus

Question 17

Renal columns

Answer 17

Bands of cortical tissue
Separate renal pyramids
In medulla

Question 18

Renal circulation order

Blood circulation

Answer 18

Renal artery ➡️ segmented arteries ➡️ interlobar arteries ➡️ arcuate arteries ➡️ cortical radiate arteries ➡️ afferent arterioles ➡️ glomerulus ➡️ efferent arteriole ➡️ peritubular capillaries ➡️ venules ➡️ cortical radiate veins ➡️ arcuate veins ➡️ interlobar veins ➡️ renal veins

Question 19

Name of the kidneys functional unit

Answer 19

Nephron

Question 20

Juxtamedullary nephrons (15%)

Answer 20

Adapted for water reabsorption
Long loop of Henle extends into medulla
No lymphatic drainage

Regulates volume of urine

Question 21

Cortical nephron (85%)

Answer 21

Small loop of Henle
Adapted for regulation of urine composition, not volume
Good lymphatic supply

Question 22

What’s the glomerulus (filtration)

Answer 22

Filter unit 
Input = afferent arteriole 
Output = efferent arteriole (smaller diameter)
High pressure 
Ball of narrow capillaries 
Sits in Bowman’s capsule

Question 23

Peri-tubular capillaries

Answer 23

Input = efferent arterioles
Output = renal venous system
Adapted for absorption - porous/low pressure

Question 24

Divide nephron of kidney into capillary and tubular portions

Answer 24

Capillary = glomerulus + peri-tubular capillaries

Tubular = PCT, loop of Henle, DCT, collecting duct

Question 25

Types of cell in tubular portion of the kidneys nephron

Answer 25

Modified epithelial cells:
Squamous, cuboidal
Microvilli
Fenestrations
Selectively permeable 
Transporter expression

Question 26

Cellular structure of glomerulus

Answer 26

Fenestrated epithelium (holes)
Podocytes = strength 
Mesangial cells - structural, contractile, phagocytic 
Negatively charged 
Collagen 
Extracellular matrix

Question 27

Glomerular filtration rate (GFR)

Answer 27

KF (kidney permeability constant) x net filtration pressure

Kf = ml min-1 mmHg-1 = dependant on membrane permeability + filtration area