Hormone Synthesis and Action

Question 1

What does the endocrine system regulate?

Answer 1

• Metabolism
• Homeostasis
• Reproduction

Question 2

Types of glands

Answer 2

• Endocrine glands
• Exocrine glands (NOT PART OF ENDOCRINE SYSTEM)
• Mixed glands

Question 3

What do endocrine glands release and where to?

Answer 3

Hormones into bloodstream (directly from cells - ductless)

Question 4

What do exocrine glands release and where to?

Answer 4

Secretions outside of the body (may be ducted)

Question 5

What do mixed glands release?

Answer 5

Hormones and other secretions

Question 6

What is negative feedback?

Answer 6

Process by which body senses change and activates mechanism to reduce it

Question 7

What is positive feedback?

Answer 7

Process by which body senses change and activates mechanism to amplify it

Question 8

3 types of hormones

Answer 8

• Protein/peptide hormones
• Steroid hormones
• Amine hormones

Question 9

What is the significance of protein hormones being hydrophilic?

Answer 9

Can be transported in blood without a carrier protein

Question 10

Where are protein hormones preformed and stored?

Answer 10

Membrane bound vesicles

Question 11

By what process are protein hormones released?

Answer 11

Exocytosis

Question 12

What are protein hormones produced as?

Answer 12

Large precursor molecules (pre-prohormones)

Question 13

What are steroid hormones made from?

Answer 13

Cholesterol

Question 14

When are steroid hormones produced and how are they released?

Answer 14

Produced as required and immediately diffuse out of cell

Question 15

Steroid hormone synthesis

Answer 15

• Cholesterol moves to mitochondrion
• Cholesterol converted to pregnenolone
• Pregnenolone processed and hormone released

Question 16

What enzyme regulates movement of cholesterol to mitochondria?

Answer 16

Steroid acute regulatory protein (StAR)

Question 17

What enzyme converts cholesterol to pregnenolone?

Answer 17

CYP11A

Question 18

How are steroid hormones eliminated and excreted?

Answer 18

• Inactivated by inactivating metabolic transformations
• Excreted in urine or bile

Question 19

Site of action of protein hormones

Answer 19

Cell surface receptors

Question 20

How do protein hormones create a response?

Answer 20

Activate a second messenger cascade to cause change in cellular function

Question 21

Site of action of steroid hormones

Answer 21

Intracellular receptors (cytoplasm or nuclear)

Question 22

How do steroid hormones create a response?

Answer 22

Hormone-receptor complex binds to hormone response elements (HREs)