Hormones and behaviour

Question 1

What are hormones?

Answer 1

• Chemical messengers that are released into bloodstream and affect the function of target cells at a distance from their source.

Question 2

How many classes of hormones are there?

Answer 2

3

Question 3

What are protein hormones?

Answer 3

• Most vertebrate hormones are proteins **composed of amino acids. **
• Can be stored in endocrine cells and include examples such as insulin and ghrelin.
• Bind to receptors on the SURFACE of target cells.

Question 4

What are monoamine hormones?

Answer 4

• Derived from a** single amino acid**.
• Include hormones like epinephrine and dopamine.
• Some act as both hormones and neurotransmitters.

Question 5

What are steroid hormones?

Answer 5

• **Produced mainly by the adrenal glands, gonads, and brain. **
• Derive from cholesterol and include cortisol and testosterone.
• Bind to receptors INSIDE target cells, and are not stored but released immediately.

Question 6

What are the 2 different glands?

Answer 6

Exocrine and endocrine.

Question 7

What are exocrine glands?

Answer 7

• Secrete products through ducts to an epithelial surface (skin or digestive tract).
• Produce substances like enzymes, mucus, sweat, and saliva.
• Include salivary glands, sweat glands, sebaceous glands, and pancreas.
• Functions in digestion, lubrication, protection, and temperature regulation.

Question 8

What are endocrine glands?

Answer 8

• Release hormones directly into the bloodstream.
• Regulate body processes such as growth, metabolism, and reproduction.
• Include glands like the pituitary, thyroid, adrenal, and pancreas.
• Hormones travel to target organs and tissues to exert effects.

Question 9

What are glands? How do they link to hormone production?

Answer 9

• A group of cells formed by ingrowth from an epithelial surface.

**- Not all glands produce hormones **

Question 10

How do hormones influence behaviour?

Answer 10

• May influence sensory, central processing, and output systems.
• Hormones do not directly cause behaviour, but change the probability of certain responses.

Question 11

What is the effect of hormones on target cells?

Answer 11

• Hormones interact with receptors, leading to activation of enzymatic pathways/changes in gene expression.
• Hormones may change cell morphology/size.
• Responsiveness depends on hormone concentration, number of target recepors, and the influence of other hormones.

Question 12

What are the 2 feedback mechanisms?

Answer 12

Positve and negative

Question 13

What is positive feedback?

Answer 13

• A process where a hormone’s release stimulates further release, amplifying its effect.
• Often seen in reproductive systems, e.g., oxytocin during childbirth.
• Leads to rapid changes or intensification of a particular behavior or physiological response.

Question 14

What is negative feedback?

Answer 14

• A regulatory process that maintains homeostasis by reducing hormone production when levels rise.
• Involves a hormone inhibiting its own release or the release of another hormone.
• Helps stabilize physiological processes and behaviors, such as temperature, metabolism, and stress response.

Question 15

What is hormone clearance?

Answer 15

• Hormones are broken down by enzymes, the liver, and bloodstream disintegration.
• Hormones are excreted via bile or urine.

Question 16

How do you determine hormone bheaviour effects?

Answer 16

• A hormonally dependent behaviour should disappear when hormone action is blocked or removed.
• Restoration of missing hormonal sources should reinstate absent behaviour.
• Hormone concentrations and the behaviour should be covariant.

Question 17

What is neural transmission vs hormonal communication?

Answer 17

Neurons:
- Travel along existing nerve tracks.
- Messages have rapid onset and offset, taking place in milliseconds (ms).
- Subject to voluntary control.

Hormones:
- Travel throughout the body via the circulatory/system,
- Effects may take minutes or hours to manifest and last longer.
- No voluntary control over relase.

Question 18

Hormone Receptors

Steroid hormones?

Answer 18

• Not water-soluble and require carrier proteins to travel in the bloodstream.
• Blind to receptors inside target cells.

Question 19

Hormone Receptors

Protein hormones?

Answer 19

• Cannot pass through plasma membranes.
• Bind to receptors on the target cell surface.

Question 20

Regulation of Receptors

Up-Regulation?

Answer 20

• Increased production of receptors.
  e.g., when hormone concentrations are low, it increases sensitivity.

Question 21

Regulation of Receptors

Down-regulation?

Answer 21

• Decreased prodcution of receptors lowers sensitivty.
• Hormones may regulate receptors for other hormones.