Module 3, Lecture 2: Homeostasis: Regulation of Osmolarity, Glucose & Oxygen

Question 1

Osmoregulation

Answer 1

Controls water and salt levels to keep fluid balance stable

Question 2

Glucose Regulation

Answer 2

Keeps blood sugar in a narrow range using hormones and nerves

Question 3

Oxygen Regulation

Answer 3

Maintains steady oxygen levels for cells to survive and function

Question 4

Loop of Henle – Function

Answer 4

• Reabsorbs water and NaCl
• Creates concentrated urine and conserves water.

Question 5

Descending Limb

Answer 5

• Water leaves (via aquaporins), salt stays
• Water exists by osmosis
• filtrate becomes more concentrated

Question 6

Ascending Limb – Thin Segment

Answer 6

• Impermeable to water; NaCl diffuses out

Question 7

Ascending Limb – Thick Segment

Answer 7

• NaCl actively transported out into interstitial fluid
• Impermeable to water

Question 8

Osmolarity at Loop Tip

Answer 8

• Highest solute concentration
• Mainly NaCl & urea, due to water loss

Question 9

Hyposmotic

Answer 9

Water loss

Question 10

Hyperosmotic

Answer 10

Salt lose

Question 11

ADH (arginine vasopressin)

Answer 11

Hormone that helps body keep water by letting it be reabsorbed, so you pee out less

Question 12

Kangaroo Rat

Answer 12

Desert rodent that adapted to dry environments by conserving water through highly efficient kidneys and concentrated urine

Question 13

How does the kangaroo rat save water during kidney filtration and reabsorption?

Answer 13

• Lots of ADH hormones
• Longer loop of Henle

Question 14

What happens when glucose is too low?

Answer 14

Secrete glucagon

Question 15

What happens when glucose is too high?

Answer 15

Secrete insulin

Question 16

What does the pancreas make?

Answer 16

Makes both insulin and glucagon

Question 17

Pancreatic Islets

Answer 17

Clusters of endocrine cells in the pancreas

Question 18

Alpha Cells

Answer 18

Found in islets; produce glucagon

Question 19

Beta Cells

Answer 19

Found in islets; produce insulin

Question 20

How do animals keep blood glucose steady when not eating?

Answer 20

Animals use glycogenolysis, gluconeogenesis, and ketosis to make or use energy. Hormones like glucagon, cortisol, and epinephrine keep glucose levels steady.

Question 21

Glycogenolysis

Answer 21

breaks down stored glycogen

Question 22

Gluconeogenesis

Answer 22

makes glucose from fats/proteins

Question 23

Ketosis

Answer 23

Uses fat for energy

Question 24

How can arctic ground squirrel maintain blood glucose during 7+ month hibernation?

Answer 24

• Bulk up before hibernating
• Become hypothermic and reduce metabolic rate
• Reduce insulin secretion and lower metabolic rate

Question 25

Bird lungs

Answer 25

Two cycles of inhalation and exhalation are required to pass one breath through the system

Question 26

Bird lungs - step 1

Answer 26

First inhalation draws oxygen rich air into posterior sacs

Question 27

Bird lungs - step 2

Answer 27

First exhalation moves fresh air into lungs

Question 28

Bird lungs - step 3

Answer 28

Secon inhalation moves stale oxygen from lung into anterior air sacs

Question 29

Bird lungs - step 4

Answer 29

Second exhalation moves air out of anterior air sacs