The Endocrine System Flashcards
What does the endocrine system do?
Supplements the work of the nervous system
Secretes hormones through the blood vessels
Regulates physiological processes of the body
What are parts of the endocrine system?
Pineal gland
Thyroid
Gonads - testes/ovaries
Pituitary gland
Adrenal gland
What is the process of what happens in the endocrine system?
- Hypothalamus sends a releasing hormone to the pituitary gland
- Pituitary gland sends a stimulating hormones into the bloodstream
- That hormone signals the target gland to release its hormone
- Levels of the hormone rise in the bloodstream
- Hypothalamus shuts down the releasing hormone
- Pituitary shuts down the stimulating hormone
- Target gland slows down its secretion
- Results in a stable concentration of hormones in the bloodstream.
What does the hypothalamus do?
Releases growth releasing hormone (GRH) which stimulates the pituitary gland
What does the pituitary gland do?
Anterior pituitary:
Releases ACTH which then stimulates the adrenal cortex, releasing adrenaline
Posterior pituitary:
Releases oxytocin which stimulates the release of prostaglandins that produce contractions during childbirth and lactation during breastfeeding
What does the pineal gland do?
Produces melatonin which regulates biological rhythms eg. the sleep-wake-cycle.
What does the thyroid gland do?
Releases thyroxine which regulates our metabolism
What are the parts in the adrenal gland?
Adrenal medullae - middle
Adrenal cortex - outside
What does the adrenal medulla do?
Releases both adrenaline and noradrenaline
Noradrenaline releases glucose, increases blood flow, inhibits the bladder and bowel.
Adrenaline increases blood pressure, expands air passages and enlarges the pupils.
What does the adrenal cortex do?
Releases cortisol which regulates blood pressure, metabolism, stimulates release of glucose for energy
Sometimes called the ‘stress’ hormone
What do the ovaries do?
Produce oestrogen which regulates the female menstrual cycle, menstruation and pregnancy.
What do the testes do?
Produce testosterone
testosterone develops the male sex characteristics during puberty, addition to muscle development
