Renal

Question 1

What is the overall function of the renal system?

Answer 1

To produce, store and eliminate urine
Regulate fluid, electrolyte and acid-base balance
Regulate BP
Stimulate erythropoietin

Question 2

What organs comprise the renal system?

Answer 2

Kidney
Ureter
Bladder
Urethra

Question 3

What are the 3 regions of the kidney?

Answer 3

Renal Cortex
Renal Medulla
Renal Pelvis

Question 4

What is the renal cortex?

Answer 4

Outer region of kidney
Numerous renal corpuscles (filtration unit)
Produces and releases erythropoietin to stimulate RBC production when hypoxia detected

Question 5

What is the renal medulla?

Answer 5

Middle region of kidney
Many calyces/renal pyramids which contain tubules and collecting ducts that transport urine to the renal pelvis

Question 6

What is the renal pelvis?

Answer 6

Inner region of kidney
Carries urine from calyces to ureters

Question 7

What is a renal calculi?

Answer 7

Kidney stone
Hard deposit of mineral/salt that form when concentration of minerals are high and urine lacks the substances to prevent crystals sticking together
Ranges in size and location
Factors include dehydration and foods high in oxalate, salt and protein
SX: waves of stabbing pain in back/side that may radiate to groin/abdo, hematuria, polyuria, persistent urge but small amounts of urine

Question 8

What is a nephron?

Answer 8

The functional unit of the kidney
Consists of a renal corpuscle and a renal tubule

Question 9

What is a renal corpuscle?

Answer 9

Glomerulus = group of specialised capillaries surrounded by Bowman’s Capsule
Glomerulus filters blood so that small molecules (water, ions) are removed from the blood and go into Bowman’s capsule

Question 10

What is a renal tubule?

Answer 10

A long tube comprised of a proximal convoluted tubule, loop of Henle and distal convoluted tubule
Involved in the movement of substances in and out of the blood and tubule - reabsorbs important substances into blood and secretes waste products into the urine

Question 11

How much can an adult bladder hold?

Answer 11

500ml

Question 12

Where is the bladder located?

Answer 12

Pelvis

Question 13

What is prostate disease?

Answer 13

Inflammation of prostate puts pressure on urethra which restricts urine passage
SX: abdo/pelvic pain, urine burn, hematuria, polyuria

Question 14

What are the 4 stages of kidney filtration?

Answer 14

Glomerular filtration
Tubular reabsorption
Tubular secretion
Excretion

Question 15

What is glomerular filtration?

Answer 15

Blood flows into glomerulus
Small molecules forced into Bowman’s Capsule = filtrate
Process is driven by pressure gradient between the glomerulus and Bowman’s Capsule

Question 16

What is tubular reabsorption?

Answer 16

Renal tubule walls have special cells that absorb specific substances
Molecules are selectively reabsorbed from tubules into blood (active + passive)
Aim to balance electrolytes and fluid

Question 17

What is tubular secretion?

Answer 17

Waste substances are actively transported from blood into tubule
Allows waste not filtered by glomerulus to still be excreted

Question 18

What is excretion (stage of filtration)?

Answer 18

Fluid remaining after tubular action is urine
Tubule —> collecting duct —> renal pelvis —> ureter —> bladder —> urethra

Question 19

What signals the brain that we need to urinate?

Answer 19

Stretch of the bladder wall

Question 20

What is voluntary control of urination?

Answer 20

External sphincter consciously relaxes

Question 21

What is involuntary control of urination?

Answer 21

Micturition reflex
Distended bladder sends signal to spinal cord = reflex response
Detrusor muscle (bladder wall) contracts and internal sphincter relaxes

Question 22

What is urinalysis retention?

Answer 22

Inability to empty, start or maintain voiding
Acute: sudden and complete inability (obstruction, meds, nerve issue)
Chronic: doesn’t empty completely (muscle weakness, blockage)

Question 23

How does antidiuretic hormone act in the renal system?

Answer 23

Released by posterior pituitary in response to changed blood osmolarity and volume
Acts on the renal tubules + ducts to increase water reabsorption

Question 24

How does aldosterone work in the renal system?

Answer 24

Acts on the tubules to increase reabsorption of sodium and increase excretion of potassium
The conservation of sodium helps regulate electrolytes and fluids

Question 25

What is atrial natriuretic peptide?

Answer 25

Produced by the atria when blood volume or stretch is too much
Increases the excretion of sodium and water (opposite to aldosterone)

Question 26

What is the renin-angiotensin-aldosterone system?

Answer 26

Regulate BP, fluid and electrolytes
1. Juxtaglomerular cells in kidney sense low BP/Na and release renin into blood
2. Renin acts on angiotensinogen protein (from liver) converting it to angiotensin I
3. Angiotensin converting enzyme (from lung) converts angiotensin I to angiotensin II
4. Angiotensin II causes vasoconstriction, release of aldosterone and stimulates thirst

Question 27

How does the paediatric renal system differ?

Answer 27

Immature kidney = poor fluid balance ability
Excretion of drugs varies
Inefficiency to concentrate urine leads to fluid loss
Low excretion of hydrogen risks acidosis

Question 28

How does the geriatric renal system differ?

Answer 28

Enlarged prostate leads to retention
Bladder capacity reduced
Polypharmacy and comorbidity = renal failure
Reduced filtration from stiff vessels and reduced blood flow

Question 29

What are the SX of a UTI?

Answer 29

Polyuria, urgency, burn/pain, cloudy or bloody urine, pelvic pain
If upper UTI: fever, back/flank pain, N+V