Lecture 32: Endocrine System

Question 1

Endocrine System:

Answer 1

• Regulates internal environment by secreting hormones that travel through the bloodstream to target areas

Question 2

Hormones are _____ _______ regulators:

Answer 2

• Long distance

Question 3

Major endocrine glands include:

Answer 3

• Hypothalamus
• Pituitary Gland
• Thyroid Gland
• Adrenaline Glands

Question 4

Lil hormone pathway:

Answer 4

• Hormone secreting cell secretes hormone
• Hormone travels through blood stream
• Targets cells in one or more distant places in the body

Question 5

Hormones are…

Answer 5

• Chemical messengers produced in one location and transported to a second location (target cells) where they elicit an effect

Question 6

Water-soluble hormones include…they are made….

Answer 6

• Peptides
• Catecholamines
• And stored inside the cell until required

Question 7

Lipid-soluble hormones include…..

Answer 7

• Steroids

- Thyroid hormones

Question 8

The difference between steroids and thyroid hormones…

Answer 8

• Steroids aren’t made until required

- Thyroid hormones are stored and released when required

Question 9

How do water soluble hormones have an effect on cells?

Answer 9

• Water soluble hormone recognises it’s receptor protein
• Binds and changes receptor protein to change shape slightly
• This activates another protein inside the cell that is attached to the receptor protein
• Activates specific transporters
• Domino effect inside the cell

Question 10

Give an example of a water soluble hormone having an effect on a cell:

Answer 10

• Epinephrine has multiple effects in mediating the body’s response to short-term stress
• Epinephrine binds to receptors on the plasma membrane of liver cells
• This triggers the release of messenger molecules that activates enzymes and result in the release of glucose into the bloodstream

Question 11

How do lipid-soluble hormones have an effect on a cell?

Answer 11

• Hydrophobic, lipid-soluble
• Easily goes through plasma membrane
• Once inside cell it can bind to specific receptor protein
• That receptor protein is always a transcription factor
• This binds to the promoter in the nucleus and makes mRNA
• Makes protein

Question 12

Which has the quickest response: Water-soluble hormones or lipid-soluble hormones?

Answer 12

• Water-soluble

Question 13

How do hormones have a specific effect on their specific target cell?

Answer 13

• Hormone = key
• Receptor = lock
• Specific matching system
• A hormone can only affect cells with specific receptors for that hormone

Question 14

Regulation of target cell sensitivity:

Answer 14

• Sensitivity of a target cell depends on the number of receptors expressed for that hormone
• Receptors are constantly degraded and synthesized to ensure efficiency
• Provides a method to change receptor number when needed
• Synthesis > Degradation –> Up-regulation
• Synthesis Down-regulation

Question 15

Hormones are slower than the neuronal system because of…

Answer 15

• Travelling distance

- They have to be secreted