W3: Animal Behaviour (Hormones & Behaviour) [Dr. Madikiza] Flashcards
Why is it important to understand animal behaviour? / Why are we learning about animal behaviour?
Hormones?
= chemical substances that are secreted in one part of the body, that causes changes in other parts of the body.
Pathways/Ways in which hormones are secreted by? (2)
- Endocrine glands.
- Neurons.
Hormones secreted by endocrine glands?
= hormones.
Hormones secreted by neurons or nerve cells?
= neurohormones.
Hormones vs Neurohormones? (3)
1) Hormones
= secreted by endocrine glands.
= take days to have an effect.
= not localised (travel through all vessels of the body).
2) Neurohormones
= secreted by neurons/nerve cells.
= quick but not long-lasting.
= very localised.
Types of hormones? (2)
- Peptide hormones.
- Steroid hormones.
Peptide hormones?
= protein molecules or amino acid chains.
Peptide hormones attributes? (4)
- Water soluble.
- Fat insoluble (can’t pass through lipid membranes).
- Binds to the receptors on the cell surface.
- Short-term changes in the cell membrane & long-term changes in protein function.
How do peptide hormones cause short-term changes in the cell membrane & long-term changes in protein function?
Egs of Peptide hormones? (2)
- LH.
- FSH.
- All secreted by the pituitary gland.
Mechanism of action of peptide hormones?
Hormones bind to the receptors found on the cell membrane and …
Steroid hormones?
= chemically derived from cholesterol.
Steroid hormones attributes? (5)
- Highly fat soluble (can pass through cell membranes of lipids).
- Made of cholesterol.
- Primarily secreted by gonads & adrenal glands.
- Divided into 4 major classes.
- Attach to DNA & affect gene expression and protein synthesis.
4 major classes of Steroid hormones?
- Progestins.
- Androgens.
- Estrogens.
- Corticosteroids.
List of sex steroids? (3)
- Progestins.
- Androgens.
- Estrogens.
Mechanism of action for Steroid hormones
Hormones pass through the membrane, goes through the cytoplasm and nucleus of the cytoplasm, and then affects gene expression & protein synthesis.
Thing to note about hormones & behaviour?
Hormones don’t influence/have a direct influence on behaviour, instead they have an effect at the cellular level (enzymes, etc) & these changes then cause changes in the animal’s behaviour.
How do hormones affect behaviour? (3)
- Sensory systems.
- Development of the CNS.
- Effector muscles.
Sensory systems (perceptual mechanism)?
= hormones influence the ability to detect stimuli & the preference of a particular stimuli.
Development/Activity of the CNS?
= hormones influence the CNS & different regions of the brain.
Muscles important in the execution of behaviour?
= hormones influence by affecting the muscles & motor neurons.
Egs of Sensory systems? (2)
- Newts.
- Sticklebacks.
Explain Newts? (3)
- Effects on sensation & perception.
- Vasotocin affects how males react to visual. chemical & tactile stimuli from females.
- Males rely on visual cues (eg, size, shape, colour) & olfactory cues to identify a females & determine whether to mate with a female.
Explain Three-spined sticklebacks? (3)
- Effects on preference.
- Thyroxine can modify preference in these fish.
- High levels of Thyroxine influence the migrating behaviour of sticklebacks (change the preference of the fish of whether they are going to stay in marine or stream water.