The Endocrine System Flashcards
Which other systems is the endocrine system closely linked to?
The nervous and immune systems.
What are the means of control in the endocrine system?
Hormones transported via the bloodstream to most of the cells in the body.
What is the speed response of endocrine compared to nervous?
Endocrine takes seconds or days whereas nervous takes milliseconds. Endocrine has a prolonged effect.
Where is the hypothalamus located?
This is between the cerebellum and brainstem, houses pituitary gland and hypothalamus.
What does the hypothalamus regulate?
This is the ‘control freak’, detects if there are changes or not. Regulates temp, fluid volume, growth, pain and pleasure, hunger and thirst.
What are some examples of hypothalamus hormones?
-CRH
-TRH
-GH
What is the meaning of releasing and inhibiting hormones?
These don’t have a direct effect but inhibit other endocrine glands (eg TRH causes pituitary gland to release TSH).
Where is the pituitary gland located?
Sits beneath hypothalamus, ‘master gland’, divided into anterior and posterior pituitary glands.
What kind of system is the anterior pituitary connected to?
Connect to hormonal.
What kind of system is the posterior pituitary connected to?
Connect to neuronal (synaptic control).
What are the anterior pituitary hormones?
-growth hormone (bone and muscle)
-prolactin (lactation)
-stimulating hormones (TSH, FSH, LH, ACTH).
What is TSH?
The thyroid stimulating hormone and this stimulates the thyroid to produce T3 and T4, also stimulate the growth of thyroid gland.
What are the posterior pituitary hormones?
-ADH (in kidney, reduces urine output)
-oxytocin (in uterus/ breast, milk release).
Which hormones are present in the kidneys?
-1,25 dihydroxyvitamin D (calcium absorption in intestines)
-renin (RAAS)
-erythropoietin (increases RBC production).
Which hormones are present in the ovaries?
-estrogen
-progesterone (menstrual cycle, maintains pregnancy).
Which hormones are present in the testes?
-androgens
-testosterone (secondary sexual characteristics, sperm production)
Which hormones are present in the thymus?
-release thymosin and thymopoietin
-affects maturation of T lymphocytes
What are the functions of the pineal gland?
-screte melatonin
-role in sleep wake cycles, body temp and sleep
-ageing and fertility.
What are the functions of the thyroid gland?
-metabolism
-sweating
-HR, RR
-produces thyroid hormone and calcitonin
-takes up iodine from blood
-calcitonin (lowers calcium levels).
Why is iodine important for production of T3 and T4 hormones?
T3 contains 3 I2 molecules, T4 contains 4.
What are the functions of thyroid hormones?
-increase metabolic rate (low levels cause you to put on weight as can’t process calories)
-increase heat production
-regulate metabolism
What do follicular cells do in the thyroid?
These extrete T3 and T4.
What do thyroid C cells do in the thyroid?
Produce calcitonin- lowers blood calcium and phosphate levels.
Where are parathyroid glands?
Embedded in the thyroid gland.
What do the parathyroid glands secrete and function?
Chief cells secrete parathyroid hormone (PTH)- increases blood calcium levels.
What hormones does the adrenal medulla secrete?
Adrenaline and noradrenaline (involved with the stress response).
What hormones does the adrenal cortex secrete?
Steroid hormones:
-glucocorticoids like cortisol
-mineralocorticoid like aldosterone
-adrenal androgens (converted to testosterone).
What happens to other levels if you have high aldosterone?
High Na+ and H20 retention, low K+ and H+ (inhibiting) and therefore, low pH.
What are the functions of cortisol?
-regulates metabolism and stress response (chronic stress)
-raises blood sugar
-breakdown of fat and protein
-anti- inflammatory actions
-immune suppression.
What are the functions of aldosterone?
-maintains salt and water balance
-acts on kidney to retain water
-regulates blood volume and blood pressure
Where is the pancreas located?
Between the spleen and duodenum.
What are the 2 main functions of the pancreas?
-digestive enzymes
-releases two hormones: insulin and glucagon.
In pancreatic tissue, what kind of cell is glucagon in?
Alpha cells.
In pancreatic tissue, what kind of cell is insulin in?
Beta cells.
In pancreatic tissue, what cells are digestive enzymes in?
Exocrine cells.
What is glycogenesis?
Turning glucose to glycogen in the liver.
What is glycogenolosis?
Turning glycogen to glucose in the liver.
