Lecture 7: Urinary system

Question 1

What are the functions of excretory system?

Answer 1

1-excretion
2-osmoregulation
3-produces erythroietin
4-produces renin
5- activates vitamin D

Question 2

what is excretion?

Answer 2

Removal of nitrogenous waste products (urea)

Question 3

what is osmoregulation?

Answer 3

Regulating solute and water balance (maintains osmotic pressure)

Question 4

what does erythropoietin produce?

Answer 4

production of red blood cells

Question 5

why are kidneys very important?

Answer 5

to maintan homeostatsis

Question 6

what does renin do?

Answer 6

Enzyme that regulates blood pressure by activating angiotensin

Question 7

where is urea made in?

Answer 7

in the liver by combining NH3 with CO2

Question 8

true and false: urea can be transported and stored at low concentrations

Answer 8

False, at high concentrations

Question 9

what does urea impact?

Answer 9

has a large impact on water balance (osmoregulation)

Question 10

what does our kidneys regulate?

Answer 10

regulate composition of blood
which regulates composition of ISF
which regulate composition of cells.

Question 11

what is the pathway of urine?

Answer 11

kidneys -> ureters -> urinary bladder -> urethra

Question 12

where is urine stored?

Answer 12

in the urinary bladder

Question 13

is the internal urethral sphincter voluntary or involuntary?

Answer 13

involuntary

Question 14

is the external urethral sphincter voluntary or involuntary?

Answer 14

voluntary

Question 15

what are the two distinct regions of the kidney? what do they both contain?

Answer 15

1- outer renal cortex
2-inner renal medulla
they both contain nephrons and
associated blood vessels

Question 16

how does blood enter and exit kindneys?

Answer 16

enter the renal artery and exit renal vein

Question 17

what percentage of resting cardiac output passes through the kidneys every minute?

Answer 17

20%

Question 18

how many times is plasma volume filtered by kidneys?

Answer 18

60 times per day

Question 19

what are nephrons and collecting ducts lined by and what does that do?

Answer 19

they are lined by transport epithelium that is specialized to reabsorb water and solutes to control the composition of urine

Question 20

Name the two parts of the nephron

Answer 20

1- renal corpuscle
2- renal tubule

Question 20

what are the three process of urine formation?

Answer 20

1- glomerular filtration
2- tubular reabsorption
3- tubular secretion

Question 21

what does glomerular filtration do?

Answer 21

• Fluid is pushed out of the glomerular capillaries
  into Bowman’s capsule
• Mostly non-selective (only depends on size)

Question 22

what does tubular reabsorption do?

Answer 22

• H2O and valuable solutes are reabsorbed back
  into the blood (glucose, amino acids, some salts)
• Much more selective!

Question 23

what does tubular secretion do?

Answer 23

• Some solutes are selectively pumped by active
  transport into the nephron (some salts, H+,
  drugs)

Question 24

where does the fluid from nephrons drain into?

Answer 24

a collecting duct

Question 25

where does the collecting duct drains into?

Answer 25

drain into the renal pelvis,
which drains into the ureter

Question 26

what are podocytes?

Answer 26

Specialized “octopus-like” cells called podocytes form the inner layer of Bowman’s capsule and
wrap around the glomerular capillaries

Question 27

what are filtration slits?

Answer 27

Spaces between foot-processes of podocytes

Question 28

how is flow driven in the glomerular capillaries?

Answer 28

by high hydrostatic pressure

Question 29

what are some examples of filtrates?

Answer 29

water, salts, sugars, amino acids, nitrogenous waste

Question 30

what happens during reabsorption and secretion?

Answer 30

99% of water and most of the glucose, amino acids and vitamins in the filtrate are reabsorbed!

Question 31

Filtrate has that same composition of blood except

Question 32

what are the two types of nephrons?

Answer 32

juxtamedullary(20% of nephrons) and cortical

Question 33

what can justamedullary nephrons create?

Answer 33

can create a steep osmotic gradient in the kidney to produce urine that is hyperosmotic to the body.