Week 26 urinary system 1

Question 1

Urinary system

Answer 1

Made up of;
-Kidneys -> pressure filter producing urine from blood, renal pelvis which urine is drained into
-Ureters -> transport urine to bladder
-Bladder -> stores urine
-Urethra -> tube between bladder and external environment, transports urine out of the body

Question 2

Excretion

Answer 2

Removal of metabolic wastes from body

Question 3

Function of the kidneys:

Answer 3

-Regulate blood volume and electrolytes
-Removal of urea from blood stream
-Conserving nutrients
-Regulating acid - base balance
-Regulate blood pressure
-Calcium homeostasis
-Production of erythropoeitin and renin

Question 4

Kidney damage / disorders:

Answer 4

-Acute kidney injury
-Chronic kidney disease
-Polycystic kidneys
-Kidney infection
-Kidney stones

Question 5

Kidneys:

Answer 5

Form the urine,
Three major renal processes:
1) Filtration
2) Tubular reabsorption -> passive and active process returning material to the blood from the filtrate
3) Tubular secretion -> removing material from the blood into the filtrate

Question 7

Substances filtered / reabsorbed

Answer 7

-WATER -> Glomerular filtrate 120/180 l/day (urinary volume 1.5l/day approx -> most of water filtered is reabsorbed)
-SODIUM CHLORIDE -> nearly all NA+ and Cl- is reabsorbed to maintain internal O.P
GLUCOSE -> Reabsorbed as long as plasma glucose < 200mg/100ml
-HYDROGEN IONS -> Normal diet generates H+ ions and kidneys eliminate them
-UREA -> end product of protein metabolism, 2/3 of that filtered is passed out in urine - remainder is reabsorbed
-TOXIC SUBSTANCES -> body metabolites drugs and drug metabolites - some of these may be actively secreted

Question 8

Urine

Answer 8

High concentrations of;
-Urea
-Uric acid
-Creatinine
-K+
-Other substances that are toxic
(Rest reabsorbed)

Question 9

Kidney : structure

Answer 9

-Renal cortex
-Renal medulla
-Renal pelvis
-Renal pyramid
-Ureter

Question 12

The nephron

Answer 12

-The functional unit of the kidney (renal corpuscle and tubule)
-Each nephron has two components:
->Vascular (blood)
->Tubular (filtered fluid)
-Some of the nephron is in renal cortex -> outer region and granular
-Some of the nephron is in renal medulla -> inner region and made up of triangles (renal pyramids)

Question 13

Nephron -> vascular components

Answer 13

Starts with the afferent arteriole (aa) -> this splits into the glomerulus (g) which is a ball of capillaries responsible for filtration -> these then rejoin to make the efferent arteriole (ea) - (a venule) -> this then splits again into peritubular capillaries, a second capillary bed that supplies the renal tissue with blood, receives compounds reabsorbed by tubule and is a source of compounds secreted by tubule

Question 14

Nephron - tubular component

Answer 14

Composed of epithelial cells
-Bowmans capsule (BC) -> encloses glomerulus, in cortex, where filtration occurs
-Proximal convoluted tubule (PCT) -> in cortex, responsible for most reabsorption/ secretion
-Loop of henle (LH) -> cortex/medulla, responsible for osmotic gradient in medulla
-Distal convoluted tubule (DCT) -> in cortex, ‘fine-tuning’ of solute / water reabsorption
-Collecting tubules / ducts (CD) -> in cortex/ medulla, ‘fine-tuning’ of urine concentration