Biology - Chapter 11.9: Excretory System

Question 1

4 Main Processes that occur at Nephron

Answer 1

1) Filtration
2) Reabsorption
3) Secretion
4) Excretion

Question 2

Filtration

Answer 2

• occurs at glomerulus
• blood from afferent arteriole enters glomerulus
• fenestrations allow small substances (water and solue) to be filtered into the Bowman’s capsule while large substances remain in the blood
• efferent arteriole forms the peritubular capillaries

Question 3

Reabsorption

Answer 3

• Throughout the nephron, water and solutes that the body needs are reabsorbed from filtrate back into the blood
• Water is reabsorbed into the blood as filtrate travels down the descending limb
• Solutes are reabsorbed as filtrate travels up the ascending limb

Question 4

Secretion

Answer 4

• Occurs at the distal convoluted tubule and the proximal convoluted tubule
• transfer of solutions from blood vasculature directly into the nephron tubule filtrate

Question 5

Excretion

Answer 5

• Filtrate (now urine) travels from nephrons to collecting ducts, renal pelvis and then ureter
• is then peed out

Question 6

Parathyroid Hormone

Answer 6

• More blood calcium
• Stimulates calcium reabsorption in tubules
• Stimulates osteoclasts to break down bone

Question 7

Calcitonin

Answer 7

• less blood calcium
• inhibits calcium reabsorption in tubules
• inhibits osteoclasts, less bone breakdown

Question 8

Juxtaglomerular cells

Answer 8

• Can detect changes in blood pressure and sodium levels

- When blood pressure/blood sodium is low, release renin

Question 9

Renin

Answer 9

• Enzyme that activates angiotensinogen to activate it to angiotensin I
• Angiotensin converting enzyme ((ACE) acts on angiotensin I to convert it to angiotensin II (active hormone)

Question 10

Angiotensin II Effects

Answer 10

• stimulates aldosterone release
• increases Na+ reabsorption
• vasoconstrictor
• makes ya thirsty ;)

Question 11

Aldosterone

Answer 11

• Mineralocorticoid produced by adrenal cortex

- increases salt and water reabosorption and potassium secretion in distal tubules and collecting ducts

Question 12

Antidiuretic Hormone

Answer 12

• ADH/vasopressin
• released from posterior pituitary
• causes aquaporins to insert into collecting duct of nephron, increasing water reabsorption

Question 13

Atrial natriuretic peptide

Answer 13

• reduce blood volume and blood pressure
• does this by increasing glomerular filtration rate, decreasing sodium reabsorption and increasing sodium excretion, inhibiting renin