lecture 29: urinary system

Question 1

the nephron

Answer 1

• functional units of the kidney, millions work together to maintain body’s fluid and electrolyte balance

Question 2

flow of fluid through a juxtamedullary nephron

Answer 2

glomerular capsule -> proximal convoluted tubule -> descending limb of the nephron loop -> thin ascending limb of the nephron loop -> thick ascending limb of the nephron loop -> distal convoluted tubule

Question 3

flow of fluid through a juxtamedullary (next to medulla) nephron

Answer 3

type of nephron in the renal cortex, regulate concentration of urine

glomerular capsule -> proximal convoluted tubule -> descending limb of the nephron loop -> thin ascending limb of the nephron loop -> thick ascending limb of the nephron loop -> distal convoluted tubule
(look histology of the renal corpuscle)

Question 4

juxtaglomerular apparatus

Answer 4

cells here become specialized and regulate blood pressure (it an endocrine structure)

Question 5

functions of nephrons

Answer 5

• glomerular filtration: blood is filtered within the nephron
• tubular reabsorption: substances that were filtered out of the blood in the glomerulus are reabsorbed back into the bloodstream
• tubular secretion
  (filter+reabsorbed+secreted)

Question 6

details of the filtration membrane

Answer 6

1. fenestration (pore) of glomerular endothelial cells: prevents filtration of blood cells but allow all components of blood plasma to pass through
2. basal lamina of glomerulus: prevents filtration of larger proteins
3. slit membrane between pedicels: prevents filtration of medium-sized

filtration membrane is a specialized structure located within the renal corpuscle of the nephron, responsible for filtering blood and removing waste.

Question 7

glomerular filtration

Answer 7

• the fluid that enters the capsular space is called the glomerular filtrate
• avg daily volume of glomerular filtrate is 150 liters in females and 180 litres in males
  (not called urine at point)

process by which blood is filtered within the glomerulus of the nephron, the functional unit of the kidney

Question 8

ureter

Answer 8

• ureters start in renal pelvis, made up of major calyces
• psoas muscle runs anterior, joining into iliac
• transport urine from kidneys to urinary bladder

Question 9

mucosal folds

Answer 9

allow expansion of urinary bladder as it fills

Question 10

peritoneum

Answer 10

holds urinary bladder in place

Question 11

trigone of bladder

Answer 11

triangular area

Question 12

internal urethral sphincter

Answer 12

involuntarily controls opening and closing of urethra

Question 13

external urethral sphincter

Answer 13

in deep muscles of perineum (voluntarily controls opening and closing of urethra)

Question 14

external urethral orifice

Answer 14

opening of urethra to outside

Question 15

detrusor muscle

Answer 15

contracts to push urine into urethra

Question 16

internal urethral orifice

Answer 16

opening into urethra

Question 17

urethra

Answer 17

passageway for discharging urine from body

Question 18

male vs females

Answer 18

• urethra is 5x times longer in males than in females
• urethra is divided into three segments in males but only one short tube in females
• the urethra is a common duct for the urinary and reproductive systems in males. these two systems are entirely separate in females

Question 19

aging in the urinary system

Answer 19

• kidneys shrink in size and have decreased blood flow
• kidney disease
• dehydration
• urinary bladder reduces in size and capacity and muscles weaken
• urinary tract infections

Question 20

distal convoluted tubule

Answer 20

(part of renal tubule, less coiled then proximal tubule - you’ll see less)

Question 21

renal corpuscle

Answer 21

where filtration starts

Question 22

afferent glomerular arteriole

Answer 22

branch off

Question 23

collecting duct

Answer 23

collect filtrate

Question 24

papillary duct

Answer 24

empty urine into minor calyx

Question 25

proximal convoluted tubule

Answer 25

part of renal tubule

Question 26

renal cortex

Answer 26

capsules and tubules are found here

Question 27

renal medulla

Answer 27

nephron loop + connective ducts