Excretory system

Question 1

Hypotonic

Answer 1

• concentration of solute is higher in cell than solution
• water will move into cell

Question 2

Excretory system

Answer 2

• Regulates concentration of blood
• gets rid of waste and reabsorbs nutrients

Question 3

Hypertonic

Answer 3

• Concentration of solute is higher in solution than in cell
• water from the cell will move to solution

Question 4

Functions of excretory

Answer 4

1. maintaining water and salt balance - osmoregulation - Na+ ions ice cells cause osmosis
2. control of special ion regulation - K+ and Na+
3. Acid base regulation - 7.4 PH, - kidney/Nephron absorb HCo3 and excrete H+
4. Removal of metabolic waste

Question 5

What does urea contain and how do we excrete it

Answer 5

1. Deaminated protien - getting rid of ammonia: NH3 (deamination happens in the liver!!!)
2. NH3 combines with CO2 to make it 100 000x less toxic
3. Urea makes up about 2% or urine

Question 6

Why is pee yellow?

Answer 6

RBC are converted into urobilin -

Question 7

Kidneys

Answer 7

• Flat sized organ in lower back
• Fat cushion = protection
• If one kidneys is removed other one will enlarge

Question 8

Urinary bladder

Answer 8

• Where urine is temporarily stored
• controlled by 2 sphincters - 1 is under conscious control
• relaxed = drainage
• contracted = storage

Question 9

Urethra

Answer 9

• Where urine is drained
• men = 20 cm - single tract
• woman = 4 cm - one tract for repro one for pee

Question 10

Ureter

Answer 10

Tube connecting from kidneys to bladder

Question 11

Renal pelvis

Answer 11

• Opening from ureter into kidney
• cup like extensions - collecting ducts - receive urine from renal tissue

Question 12

Renal tissue

Answer 12

Inner region - renal medulla
Outer region - renal cortex

Question 13

Nephron

Answer 13

• 1 million per kidney
• FUNCTIONAL UNIT OF EXCRETORY SYSTEM
• filter blood and transport substances to urine
• embedded in cortex expands into medulla

Question 14

Nephron regions

Answer 14

1. a tube - proximal and distal and
2. a duct - collecting ducts
3. a filter - glomerulus

Question 15

Urine formation in Nephron

Answer 15

1. Glomerulus filtration
2. Tubular reabsorption - recovery of substances in proximal tube
3. Tubular reabsorption and secretion - distal tube
4. Final reabsorption

Question 16

Glomerulus filtration

Answer 16

• Filters water and solutes (no proteins) from blood
• Filtered liquid is called filtrate - contains the small solutes that can fit through hole - Na+, glucose, Ca+, amino acids, Vitamins, hormones
• filtrate collected in bowman’s capsule

Question 17

How does the glomerulus cause filtration

Answer 17

1. Increase BP
2. Selectively permeable holes in capillary walls

1600-2000L of blood per day

Question 18

Tubular Reabsorption: recovery of substances in the
proximal tubule

Answer 18

• reabsorb/recover certain important molecules from blood stream
• Lots of mitochondria
• Reabsorb Sodium for osmoregulation
• secrete H+
• absorb bicarbonate - 7.4
• reabsorb 60-70 percent of water

Question 19

Loop of Henle

Answer 19

• in second stage - tubular reabsorption proximal
  1. Descending limb
• water permeable
• High concentration of sodium outside tube - draws water out into capillaries
• causes filtrate to be more concentrated
  2. Ascending limb
• thick walls= water impermeable
• Actively pump out last Na+ from filtrate = salty medulla (hypertonic) - water wants to go to bloodstream

Question 20

Tubular reabsorption and secretion - distal tube

Answer 20

• in renal cortex
• fine tunes homeostatis -osmoregulation
• Salt and water, ADH, aldosterone secreted from filtrate secreted from filtrate
• Regulates PH
• concentration of Hyrdogen and bicarbonate
• H+ in filtrate and K+, bicarbonate in bloodstream

Question 21

Final Reabsorption in the Collecting Duct

Answer 21

• final homeo adjustments
• collecting duct descends into salty medulla - final chance to reabsorb water from filtrate
• now filtrate is very concentrated = urine
• Urea and urobilin
• Ph = 4.6-8.0 - H+ ions
• Urine drains into pelvis then ureter - bladder - toilet

Question 22

Osmotic pressure

Answer 22

• Force bc osmosis
• higher concentration = higher osmotic pressure
• blood concentration is held equal
• kidneys regulates this equality

Question 23

Osmoreceptors

Answer 23

• Made in hypothalamus from the pituitary gland
• sense concentration of blood

Question 24

If blood is concentrated

Answer 24

1. Osmotic pressure rises
2. Osmoreceptors send signals from hypothalamus to the brain
   3.Pituitary releases ADH

Question 25

ADH

Answer 25

Decrease production of urine 1. Dehydrated - ADH acts on distal tube + collecting duct - allowing more H2O to be absorbed into blood 2. Hydrated - Blood plasma is dilute = low osmotic pressures - Osmoreceptors prevent release of ADH - Distal tube and collecting duct becomes less permeable to water = more water excreted in urine

Question 26

Kidney regulation: salt

Answer 26

- When Na+ levels drop - hormone from adrenal glands - on top of kidneys release aldosterone - Aldosterone acts of distal tubules to + collecting ducts - make them reabsorb more Na+ - they absorb through active transport - water + chloride ions follow passively

Question 27

Dialysis

Answer 27

- assists via diffusion - not forced hemo = outside - more minor surgery 1x paretoneal - in abdomen - inside body -