Endocrine System Flashcards
What is the endocrine system?
The collection of glands that produce hormones regulating metabolism, growth, tissue function, sexual function, reproduction …
What are the major endocrine glands?
- Pineal gland
- Hypothalamus
- Pituitary gland
- Thymus
- Pancreas
- Gonads
- Adrenal glands
- Parathyroid gland
- Thyroid gland
Where is the thymus located?
The superior mediastinum
What is the role of the thymus?
The maturation of bone marrow derived stem cells into immunocompetent cells. (Thymosin)
(Thymus cell education)
What are the four types of hormone?
Peptide hormones
Steroid hormones
Catecholamines
Thyroid hormones
What are some of the roles of the hypothalamus?
Thermoregulation
Plasma osmolality
Heart rate
Blood pressure
Emotion, sexual behaviour
Lactation …
What does the hypothalamus produce?
ADH and oxytocin
4 stimulatory and 2 inhibitory hormones that travel to the anterior pituitary
What are the two lobes of the pituitary?
Anterior
Posterior
What is the stress response?
The activation of endocrine, nervous and immune systems to maintain homeostasis in the presence of adverse stimuli.
Where are the principal effectors of the stress response located?
The hypothalamus, the anterior love of the pituitary gland, the adrenal gland.
List the adrenal cortical hormones:
Glucocorticoids (cortisol) and mineralocorticoids (aldosterone)
What makes up the medulla of the adrenal gland?
Epithelioid cells called chromaffin cells.
Modified neurons
Describe the secretion by chromaffin cells:
Myelinated presynaptic sympathetic nerve fibres reach the chromaffin cells.
When they reach the chromaffin cells these cells release their adenaline/noradrenaline
What are the effects of adrenaline and noradrenaline?
Glycogen broken down to glucose
Increase blood pressure
Increases breathing rate
Increases metabolic rate
Increases alertness
Decreased digestive + reproductive system activity
What are the effects of mineralocorticoids?
Retention of sodium and water by kidneys
Increases blood volume and blood pressure
What are the effects of glucocorticoids?
Proteins and fats converted to glucose or broken down for energy
Increases blood sugar
Suppression of immune system
How are oxytocin and ADH released?
They are produced in the hypothalamus, travel down the neuronal axons and secreted adjacent to the capillaries of the posterior pituitary
What does the pineal gland do?
Produces melatonin
Calcified in early adulthood and is visible in x rays
What does melatonin do?
Controls the circadian rhythm
Inhibits release of gonadotrophins
