Lecture 15

Question 1

What is a hormone? What are the qualifications a hormone must meet?

Answer 1

A chemical messenger that travels through blood to reach target organs
- must be: produced by one cell, bind to and activate protein receptors located on another cell, travel in the circulatory system

Question 2

What is a primary endocrine organ?

Answer 2

An organ who’s primary function is to secrete hormones

Question 3

What are the differences between the nervous system and the endocrine system?

Answer 3

• one uses electrical signals other uses bloodstream transport
• speed of response (nervous is faster)
• duration of response (endocrine is longer)
• more global vs. More precise

Question 4

What are the three structural classes of hormones?

Answer 4

1. Amino acid derivatives
2. Peptide derivatives
3. Lipid derivatives

Question 5

How are lipid derivatives synthesized? What are some examples?

Answer 5

• modifications of cholesterol by enzymes in the smooth ER and mitochondria
• eicosanoids: prostaglandin, steroids: estrogen

Question 6

How are peptide derivatives synthesized? What are some examples?

Answer 6

• gene products: synthesized as larger inactive proteins by ribosomes and then activated through enzyme cleavage
• insulin, oxytocin, calcitonin, ACTH

Question 7

How are amino acid derivatives synthesized? Examples?

Answer 7

• modified from amino acids by enzymes
• epinephrine is produced by adrenal medulla, and stored in vesicles and released by exocytosis
• thyroid hormones are synthesized by modifying thyroglobulin with iodide and tyrosine amino acids

Question 8

What is a GPCR? What kind of hormone acts on it?

Answer 8

• G protein coupled receptors: metabotropic receptors that activate intracellular signalling
• amino acids and sometimes peptide

Question 9

What is an enzyme kinase? What kind of hormone acts on it usually?

Answer 9

• A type of enzyme-linked receptor that catalyzes intracellular reactions by adding phosphate groups to other proteins and changing their activity
• peptide hormones

Question 10

What is an intracellular hormone receptor? What kind of hormone acts on them?

Answer 10

• Proteins that are usually acting as transcription factors, enhancing genes when they are bound to their ligand
• lipid

Question 11

What are the two kinds of effects that hormones can produce? What is an example of each type

Answer 11

Homeostatic:
Allostatic:

Question 12

What are the four different ways that hormones can interact on a cell or across organ systems?

Answer 12

1. Antagonistic
2. Additive
3. Integrative
4. Permissive

Question 13

What are the similarities between endocrine and nervous systems?

Answer 13

• both direct or modify the activity of other organ systems
• both use specific chemical messengers
• both are involved in feedback and homeostasis
• Both are involved in allostatic adaptions

Question 14

How does PTH meet the criteria to be a hormone?

Answer 14

• produced by chief cells
• acts on a hormone that stimulates osteoclasts
• travels through blood stream

Question 15

Will PTH be released as soon as it is synthesized, or will it be stored in vesicles? Will PTH secreting cells have more RER or SER? Will PTH require carrier protein to transport it through the bloodstream

Answer 15

• stored in vesicles
• SER
• no carrier protein

Question 16

What is an example of endocrine allostasis?

Answer 16

Adrenal glands release cortisol to initiate fight or flight response in anticipation of stress