Hormones

Question 1

What are Hormones?

Answer 1

Chemicals secreted by one cell group (glands) that travel through blood to act on organ cells

Question 2

What are endocrine glands?

Answer 2

Glands that release hormones within the body

Question 3

What are exocrine glands?

Answer 3

Glands that ue ducts to secrete fluids outside of the body (Sweat and tears)

Question 4

What is the difference between Hormones and neural signalling?

Answer 4

NS: involves chemical release & diffusion across synaptic cleft
ES: involves hormones being releases into bloodstream to act on targets

Question 5

What are the principles of Hormone Action?

Answer 5

1. Hormones act in gradual fashion
2. Act by changing the probability or intensity of a behaviour
3. Relationship between hormones and behaviour is reciprocal
4. A hormone may have multiple effects and one behaviour can be affected by multiple hormones
5. Often have a pulsatile secretion pattern
6. Some hormones are controlled by circadian clocks
7. Hormones can interact with other hormones and can change their effects

Question 6

What are the 3 ways hormonal communication is similar to neural communication?

Answer 6

1. they both produce and store chemicals and release upon stimulation
2. both NT’s and hormones bind to receptors to stimulate targets
3. Some chemicals can act as either hormones or NTs depending area of release

Question 7

What are the 4 was neural and hormonal communication differ?

Answer 7

1. NC travels to precise points, HC spreads through whole body and is picked by cells with right receptor
2. NC is faster (ms) than HC (seconds/minutes)
3. Neural distance varies while hormones may travel over a metre
4. NC can be under voluntary control while HC is involuntary

Question 8

What are the major classes of hormones?

Answer 8

1. Peptide/Protein hormone - string of amino acids
2. monoamine hormones - a modified amino acid, could also be in brain as transmitters
3. Steroid hormones - four rings of carbon acids

Question 9

Hormone receptors are not in?

Answer 9

Ion channels

Question 10

How do hormones effect cells?

Answer 10

Hormones bind to receptors and trigger release of intracellular second messengers which then spread throughout the cell and cause alot of physiological changes. Second messenger effect in cell are rapid

Question 11

where are steroid hormone receptors?

Answer 11

Steroid hormone receptors are in cell freely floating in cytoplasm

Question 12

What are steroid hormones?

Answer 12

Steroid hormones are all made from cholesterol (testosterone, estrogen, cortisol, etc) and they are lipophilic and can pass through cell memberane

Question 13

What do steroid hormones do in cells?

Answer 13

The steroid receptor bind to DNA and acts as a transcription controlling gene expressions.
Transcription factor mediated mechanisms are slow (few hours) but are long lasting

Question 14

What are the effects of hormones on the organs?

Answer 14

1. Promote proliferation, growth, and differentiation of cells
2. Modulate cell activity and metabolism
3. Modulate hormone secretion from endocrine glands

Question 15

What is the Pituitary Gland?

Answer 15

It is the master gland of the body, it secretes many different hormones, and regulates other hormone secreting glands in body

It is separated into 2 parts

Question 16

What are the 2 separate parts of the Pituitary gland?

Answer 16

Anterior pituitary: Connected to the hypothalamus via portal (blood vessels)
Posterior pituitary: Connected by the neurons which stimulate the release of hormones

Question 17

What controls the release of hormones from the pituitary gland?

Answer 17

The hypothalamus via connections it has with different parts

Question 18

What is the Hypothalamic Pituitary-Adrenal axis?

Answer 18

it is a major neural system activated during stress. Acts in 3 ways

Hypothalamus: releases corticotropin releasing hormone
Pituitary: Acts on anterior pituitary to release adrenocorticotropic releasing hormone
Andrenal: Acts in adrenal gland which releases glucocorticoids (cortisol)

Question 19

How does the endocrine system self-regulate itself?

Answer 19

The various hormonal systems use negative feedback to control their function. Negative feedback is critical in maintaining homeostasis

Question 20

What is negative feedback?

Answer 20

Negative feedback is counteraction or reduction of an effect that occurs as a result of the effect itself