Multicellular Organisms - Hormones

Question 1

What is blood glucose regulated by?

Answer 1

Insulin and Glucagon
* Their target cells are found in the liver

Question 2

• What is a Hormone?
• Describe the specificity of Hormones

Answer 2

• Chemical messengers that are released in the blood plasma to target and bind to cells to produce a response.
• A specific hormone can only affect cells if the cells have a receptor for it.

Question 3

What happens when the blood glucose concentration:
* rises too much
* falls too much

Answer 3

• Water concentration of the blood falls and water will diffuse out of cells by osmosis.
• Body cells will not receive much glucose → unable to release as much energy in respiration.

Question 4

• In what part of the body is glucose stored?
• How is glucose stored here?

Answer 4

• Liver
• Liver cells take glucose molecules from the blood using insulin and stores them in the form of glycogen.

Question 5

Describe how the concentration of glucose is regulated

Answer 5

1. Blood glucose conc. is at a set point
2. Increase/decrease in blood glucose? → detected by cells in pancreas
3. INCREASE? - pancreas releases more insulin and less glucagon into the blood → liver cells store more glucose from the blood as glycogen, then blood glucose decreases.

DECREASE? - pancreas releases less insulin and more glucagon into the blood → liver cells break down glycogen to release glucose into the blood, then blood glucose increases.

Question 6

What are the roles of the following:
* Insulin
* Glycogen
* Glucagon

Answer 6

• insulin - helps liver cells store glucose as glycogen
• glycogen - stores glucose
• glucagon - breaks down glycogen to release glucose into the blood when needed.

Question 7

Describe the features of Hormones

Answer 7

• Made from protein
• Released from endocrine glands
• Carried in blood
• Chemical messengers
• Can have a long lasting affect