D3: Exceratory

Question 1

Organs of System

Answer 1

Kidney- Main, excretes waste and regulated water:salt balance

Ureter- Tube extending from each kidney that Carrie’s urine to bladder

Bladder- Sac that stores urine

Urethra- Tube that allows urine to exit body

Question 2

Function of System

Answer 2

Removes waste
Water balance
Removes toxins, excess salt, glucose and solvable vitamins
Regulates blood pressure (BP)

Question 3

Osmotic pressure

Answer 3

Tendency of solution to gain water

Hypertonic solution gains water (water moves out of cell into solution) so it has high osmotic pressure

Question 4

Formation of Urine: Step 1

Answer 4

Filteration- Water and solutes move from blood to renal tubule
•Blood enters glomerulus (capillaries surrounded by Bowman’s capsule)- BP pushes water and solutes from capillaries to capsule
•Filteration membrane is selectively permeable so it blocks plasma proteins, erythrocytes and platelets from passing through so they stay in blood

Question 5

Formation of Urine: Step 2

Answer 5

Reabsorption- Tubule back to blood (proximal tubule)
•Sodium ions actively transported out of nephron into blood (Cl- and HCO3- followed due to electrostatic attraction): stops when threshold reached
•Glucose/amino acids actively transported out of nephron into blood too
•Solutes and proteins create osmotic pressure that pushes water back into blood (concentrates solutes in nephron)

Question 6

Step 2: Loop of Henle

Answer 6

Descending Limb- Permeable to water but not solutes like salts

Ascending Limb- Membrane permeable to salt not water
•Thin segment- NaCl diffuses out
•Thick segment- NaCl transported out actively

Question 7

Formation of Urine: Step 3

Answer 7

Secretion- Blood to nephron
•Occurs in distal tubule (active)
•Nitrogen wastes, histamines, excess H+ and mineral levels are balanced
•Secreted ion and remaining filaments=urine

Question 8

Kidneys and blood pH

Answer 8

Blood ph maintained by acid-base buffers (bicarbonate-carbon dioxide system)

Kidneys balance out H+ and HCO3 (high blood acidity=h+ excreted and HCO reabsorbed and returned to blood

Question 9

Antidiuretic Hormone (ADH)

Answer 9

•Made in hypothalamus and stored/released from pituitary gland
•Controls how much water Kidneys absorb
•More released when dehydrated, Hugh salt intake or low BP
•Makes controlling duct more permeable to water so kidneys hold more water instead of releasing it in urine

Question 10

Hormone control of osmoregulatory functions (aldosterone)

Answer 10

•Released from adrenal glands when Na+ goes down or potassium goes up (Na is major solute in blood plasma so when it drops=drop in blood osmolarity=ADH secretion)
•Stimulates distal tubule and collecting ducts to reabsorb Na which is followed by Cl- and H2O= Net effect of retaining salt and water
•Promotes secretion of potassium in tubule

Promotes retention of Na and water which increase blood volume and maintains osmolarity