Compendium 7 - How do we get rid of toxic waste?

Question 1

what are the 3 layers surrounding the kidney

Answer 1

renal capsule - connective tissue lining kidney

adipose tissue - surrounding capsule

renal fascia - connective tissue joining adipose tissue to abdominal wall

Question 2

what is found in the hilum

Answer 2

blood vessels and nerves entering the kidneys on medial side

Question 3

outline the pathway from renal pyramid to ureter

Answer 3

renal papilla (apex of pyramid) funnel into major calyces which merge to form renal pelvis which narrows at the hilum to form the ureter

Question 4

what are the 2 types of nephrons, what % of each is there and where are they located

Answer 4

juxtamedullary nephrons (15%) - renal corpuscle is located deep in the cortex (close to the medulla)
cortical nephrons (85%) - renal corpuscle located near periphery of cortex

Question 5

what is the filtration part of the nephron and what is it made of

Answer 5

Renal Corpuscle
- glomerulus (network of capillaries)
- Bowman’s capsule (double walled chamber that filters the fluid)

Question 6

where does blood move in and out of the renal corpuscle and what causes it to filter into the nephron

Answer 6

in via the afferent arteriole and out via the efferent arteriole. the afferent is bigger that the efferent therefore it creates pressure that forces the blood through the filter.

Question 7

what cells make up the 2 layers in the bowman’s capsule

Answer 7

parietal - simple squamous
visceral - podocytes

Question 8

what are 2 characteristics of the renal corpuscle that are specialised for filtration

Answer 8

fenestrae - between blood vessels endothelial cells and basement membrane cells

filtration slits - gaps between the extensions of the podocytes

Question 9

what cells make up the proximal CT and what is reabsorbed here

Answer 9

simple cuboidal epithelium with lots of microvilli

reabsorbs Na+, K+, Cl-

Question 10

what are the cells of the loop of henle

Answer 10

simple cuboidal in thick sections and simple squamous in thin sections

Question 11

what cells make up the distal CT

Answer 11

simple cuboidal, with very few microvilli

Question 12

where are substances reabsorbed into from the nephron?

Answer 12

peritubular capillaries around tubules, that then drain into the renal vein

Question 13

what are the layers of the ureters from the innermost to outermost

Answer 13

• transitional epithelium
• mucosa
• muscularis (smooth muscle layer)
• adventitia (connective tissue layer)

Question 14

what are the layers of the bladder from the innermost to outermost

Answer 14

• transitional epithelium
• lamina propria
• submucosa
• detrusor muscle (pushes urine out)

Question 15

what are the 2 main functions of the renal system

Answer 15

• excretion of waste products from metabolism and toxic molecules
• regulation of blood volume and pressure

Question 16

what are the 3 stages in urine production

Answer 16

1. filtration
2. tubular reabsorption
3. tubular secretion

Question 17

what is renal fraction

Answer 17

proportion of cardiac output that passes through kidneys (average 20%)

Question 18

what is glomerular filtration rate

Answer 18

amount of filtrate produced each minute (roughly 125ml/min)

Question 19

what does filtrate contain

Answer 19

water, glucose, fructose, amino acids, urea, urate ions, creatinine, ions (Na+, K+, Ca2+, Cl-)

Question 20

the layer of simple cuboidal epithelium in the proximal CT has 2 surfaces, what are they

Answer 20

Apical surface = facing in
Basal surface = facing interstitial fluid

Question 21

what in the filtrate is reabsorbed

Answer 21

reabsorbed= water, glucose, fructose, amino acids, Na+, k+, Ca2+, Cl-, HCO3-

Question 22

how are substances reabsorbed

Answer 22

sodium potassium pump moves sodium out of the epithelial cells which created and conc gradient so sodium moves out and other substances move out by symport.

Question 23

what is the composition of urine

Answer 23

1% filtrate, 95% water, 2% urea, 0.05% ammonia

Question 24

what is the micturition reflex

Answer 24

process of elimination of urine from the bladder
full bladder = stretch receptors alert CNS = voluntary control relaxes sphincters and contracts bladder