17. Endocrine system Flashcards
What is the endocrine system?
A system of control which helps maintain stable chemical environment for the cells of the body to function/maintain homeostasis
What are hormones?
Chemicals released by endocrine glands into blood stream.
What do hormones do?
- Regulation (of metabolic rates)
- Maturation (e.g. of bone growth)
- Control (e.g. of reproductive cycle.)
What is the difference in the nervous response and the endocrine response?
The nervous response is rapid and short lasting, endocrine response is slow, but maintained.
Where is the hypothalamus and pituitary gland located?
Base of brain + intimately connected
What do hypothalamus and pituitary gland do?
Control many functions of endocrine glands by stimulating hormones that stimulate those other glands.
Help co-ordinate hormone releases by participating in regulatory feedback mechanisms.
What are the two lobes of the pituitary glands?
Anterior pituitary and posterior pituitary.
What is the role of the anterior pituitary (adenohypophysis)?
Receive chemical messages from the hypothalamus via the blood stream (releasing factors). Responds by making further hormones of its own
What is the role of the posterior pituitary (neuropophysis) ?
Receives secretions (hormones) from nerve cells in hypothalamus which it stores.
- Releases two hormones - oxytocin, anti diuretic hormone (ADH) they are made in hypothalamus but stored in pituitary.
What are the seven anterior pituitary hormones?
- Human Growth Hormone (hGH) (somatotrophin)
- Prolactin
- Thyroid stimulating hormones (TSH) (thyrotropin)
- Follicle stimulating hormone (FSH)
- Luteinising Hormone (LH)
- Adrenocorticotropic hormone (ACTH) (corticotropin)
- Melanocyte Stimulating Hormone (MSH)
Where are the adrenal glands located?
On top of superior poles of each kidney
Consists of inner medulla and outer corticol layer.
What hormones do the adrenal glands use?
Aldosterone, androgens/oestrogens, cortisol, adrenaline, noradrenaline.
What is the pancreas + its role?
An endocrine and an exocrine gland. Exocrine gland, releases digestive enzymes into duct that empties into small bowel. (insulin and glucagon).
What is the difference between endocrine and exocrine?
Endocrine: Releases into blood
Exocrine: Releases via ducts/opening to body surface.
Where is the thyroid gland located?
Just below and anterior to larynx
What is the thyroid gland?
A highly vascular structure composed of right and left lobes joined by an isthmus.
The hormones is deals with are thyroxine (T4), tri-iodothyine (T3) and calcitonin.
Where are the parathyroid glands located?
Usually situated behind the thyroid gland although can be anywhere in neck + upper chest.
What is the functions of the parathyroid glands?
Secrete parathyroid hormones (PTH)
- Increases blood Calcium levels by mobilisation from bone and re-absorption of Ca2+ and Mg2+ from urine.
This is the opposite effect to calcitonin from thyroid.
