Renal System

Question 1

What are the function of the renal system?

Answer 1

• production of urine
• blood volume regulation
• osmolarity regulation
• hormone production
• acid base balance
• electrocyte balance

Question 2

What is osmolarity?

Answer 2

Measure of the number of particles in a litre of the liquid they’re dissolved in

Question 3

What is osmolality?

Answer 3

Measure of the number of particles in a kg of the liquid they’re dissolved in

Question 4

What do osmolarity and osmolality measure?

Answer 4

The concentration of extra cellular fluid (plasma and serum)

Question 5

What is the hormone renin?

Answer 5

Controls blood volume and involved in hydration. Also helps to regulate blood pressure.

Question 6

What is vitamin D?

Answer 6

Helps absorption of calcium and phosphate

Question 7

What is erythropoietin?

Answer 7

Promotes red blood cell production

Question 8

What is the acid base balance?

Answer 8

To ensure that the bloodstream base is not overly acidic or alkaline. Breathing is altered to respond to this

Question 9

How is the kidney protected?

Answer 9

By a mass of fat; a sheath of fibrous connective tissue, the renal fascia, encloses the kidney and renal fat.

Question 10

How much blood does the kidney receive from the heart?

Answer 10

1/4 of the blood supply every time the heart pumps

Question 11

What is the main functional unit of the kidney?

Answer 11

The nephron, of which there are over 1 million

Question 12

What is the role of the collecting ducts?

Answer 12

To collect and transport urine to the calyces

Question 13

What is the glomerular (Bowman’s) capsule?

Answer 13

Cup shaped capsule at the end of the collecting duct which encloses a coiled tuft of capillaries, named the glomerulus

Question 14

What are the three remaining sections of the nephron continuing from the glomerular capsule?

Answer 14

• proximal convoluted tubule
• medullary loop (loop of Henle)
• distal convoluted tubule, leading into a collecting duct

Question 15

What are the three processes of urine formation?

Answer 15

Filtration, selective reabsorption and secretion

Question 16

What is the filtration process? 5 steps

Answer 16

• blood flows through the glomerulus
• water and solutes pass through capillary endothelium
• through basement membrane
• through epithelium
• into Bowman’s space becoming filtrate

Question 17

What is the selective reabsorption process? 3 steps

Answer 17

• most reabsorption occurs in proximal convoluted tubule
• less reabsorbed in loop of Henle and distal convoluted tubule
• main function of collecting ducts is to reabsorb water depending on body’s needs

Question 18

What is the secretion process?

Answer 18

• occurs at the distal convoluted tubule from peritubular capillaries
• urine is formed and traverses along ureter to be expelled

Question 19

What is the journey of the urine for secretion?

Answer 19

Travels from collecting ducts through renal papilla at bottom of renal pyramid into ureters

Question 20

What are the ureters?

Answer 20

Carry urine to urinary bladder; hollow muscular tubes approx. 25-30cm long with diameter of approx. 3mm.
Passes downwards through abdominal cavity and passes obliquely through posterior wall of bladder

Question 21

What happens when the urinary bladder and urethra are distended?

Answer 21

Bladder rises into the abdominal cavity

Question 21

What happens when urine accumulates in the bladder?

Answer 21

Stretch receptors in bladder wall activated, generating sensory (afferent) impulses which are transmitted to spinal cord where spinal reflex is initiated. This is the micturition reflex, stimulating involuntary contraction of detrusor muscle and relaxation of internal urethral sphincter, expelling urine from bladder.

Question 21

At what level of urine accumulation does the need to pass urine develop?

Answer 21

around 300-400mL in adults