Week 10 - Hormones and Behaviour Flashcards
What are hormones?
Chemical substances, formed in a specialized gland or group of cells, released into the blood that affect target cells in another organ.
Hormones reach all parts of the body, but only target cells have receptors for that hormone.
The endocrine system refers to what?
a set of glands that produce chemical messengers called hormones.
What does the pituitary gland regulate?
“Master Gland” that regulates all other EndocrineGlands, also releases growth hormone.
What does the thyroid gland regulate?
Metabolism, body heat, bone growth.
What do the parathyroids regulate?
Use of Calcium and Phosphorous.
What does the hypothalamus gland regulate?
Links nervous system to endocrine system.
What does the adrenal gland regulate?
Response in emergency or stressful situations, metabolism, blood pressure, salt balance.
What are the activational effects of hormones?
Short-term, reversible effects that occur in the fully developed organism (e.g. alteration of transmission in neural networks that respond to certain aspects of the environment).
What are the organisational effects of hormones?
Long-term, irreversible effects on tissue differentiation and development (e.g. brain, ovary) that can either directly (brain) or indirectly (ovary) influence behaviour.
What are the two major classes of hormones the endocrine system produces?
protein hormones and steroid hormones.
What are protein hormones?
These comprise amino acids. They exert their effect by binding to the membrane receptor of the target cell.
What are steroid hormones?
These are derived from cholesterol from the diet and exert their effects in two ways:
i) They bind directly to membrane receptors.
ii) As they are fat-soluble they pass through cell membranes where they attach to receptors in the cytoplasm. Here they determine gene expression.
Differentiate peptide hormones and polypeptide hormones.
Both are protein hormones comprising of amino acids. those that are only several amino acids in length are called peptide hormones, whereas larger ones are called polypeptide hormones.
What are the three main types of protein hormones?
insulin, glucagons, and leptin.
What is insulin?
A protein hormone, made in the pancreas, it increases the entry of glucose into the cells and regulates fat storage.
What are glucagons?
A protein hormone, made in the pancreas, are responsible for increasing the conversion of stored fats to blood glucose.
What is leptin?
A protein hormone, produced by the fat cells, informs the brain how much fat is contained in the body.
How does leptin relate to appetite?
When leptin levels are high appetite is decreased. When leptin levels are low appetite is increased and bodily activity is reduced.
What are the main types of steroid hormones?
corticoids and sex steroids.
What are the main types of corticoids (explain them)?
Glucocorticoids(principally cortisol) are released by the adrenal glands in response to stress. They increase the breakdown of fats and proteins into glucose to trigger escape or defence (“fight or flight”).
Mineralocorticoids(e.g. aldosterone) are also produced by the adrenal glands and reduce salt secretion in the kidneys.
What are the three sex steroids?
Androgens, estrogens, and progesterone.
What is androgen?
Testosterone, is produced in large amounts in males and has masculinising and defeminising effects; maintaining male secondary sexual characteristics (sex distinguishing features that are not directly related to reproduction) and promoting courtship, aggressive and sexual behaviours.
What is estrogen?
Estradiolis produced in large amounts in females and has feminising effects, promoting female secondary sexual characteristics, water retention, calcium metabolism, sexual behaviour and maternal behaviours.
What is progesterone?
prepares uterus and breasts for pregnancy and regulates the stages of pregnancy.
True or false: sex steroids are sex-specific?
False, both males and females produce androgens and estrogens though their relative concentrations differ.
True or false: Individual differences in behaviour and physiology reflect differences in hormone concentration?
False, While overall concentration is indeed important, of equal importance is the receptivity of the cells to the hormone. A high hormone concentration will have little effect if cells lack receptivity. An excellent example of this is Androgen Insensitivity Syndrome.
What two key structures control hormone release?
The hypothalamus and the pituitary gland.
What is the primary purpose of the hypothalamus?
To maintain homeostasis.
The DNA molecule is packaged into thread-like structures called what?
Chromosomes.
In humans, each cell nucleus contains how many pairs of chromosomes?
23 for a total of 46.
What are autosomes?
The first 22 pairs of chromosomes not including the sex chromosome.
What is Y?
The male sex chromosome for many species.
Differentiate the Wolffian system from the Mullerian system.
Wolffian system – male system. Mullerian system – female system. All babies begin with both sets of ducts, differentiation happens in the third month.
Later in pregnancy, females secret large amounts of hormones like oxytocin and prolactin, what is the purpose of these hormones?
Prolactin is necessary for milk production. Oxytocin is associated with maternal behaviour and social attachment.
