Endocrine System

Question 1

Steroid Hormones

Answer 1

lipid- solube.
bind to transport proteins in bloodstream, then diffuse across cell membrane and combine with receptor protein in nucleus or cytoplasm. the hormone-receptor complex activates genes controlling the synthesis of particular proteins, by binding to promoter section of the gene and either stimulating or inhibiting protein synthesis. slow to take effect, but long lasting.

Question 2

Protein & Amine Hormones

Answer 2

water-soluble.
bind to receptors on cell membranes, which causes a secondary messenger to diffuse through cell and activate particular enzymes. fast to take effect, but short lasting.

Question 3

Hypothalamus

Answer 3

• secretes releasing and inhibiting factors, which stimulate and slow down the secretion of a hormone. (both of these factors through blood vessels to the anterior lobe of pituitary gland)
• other hormones are produced by the hypothalamus and then taken to the posterior lobe of the pituitary gland via nerve fibres

Question 4

Anterior lobe

Answer 4

controlled by releasing and inhibiting factors.
produces and releases:
Follicle-stimulating hormone
Luteinising hormone
Growth hormone
Thyroid-stimulating hormone
Adrenocorticotropic hormone
Prolactin

Question 5

Posterior lobe

Answer 5

releases:
Oxytocin
Anti-diuretic hormone

Question 6

FSH

Answer 6

stimulates the development of the follicles in the ovaries, and the production and maturation of sperm in the testes

Question 7

LH

Answer 7

stimulates ovulation and forms corpus luteum in the ovaries, and the production and secretion of testosterone in the testes

Question 8

Growth hormone

Answer 8

stimulates body growth by increasing the rate of protein synthesis; secreted throughout life

Question 9

TSH

Answer 9

stimulates production and secretion of the hormones from the thyroid gland

Question 10

ACTH

Answer 10

stimulates the production and secretion of the hormones from the adrenal cortex

Question 11

Prolactin

Answer 11

initiates and maintains milk production in females

Question 12

Oxytocin

Answer 12

stimulates the contraction of uterine muscles, especially during labour, and also stimulates contraction of cells in the mammary glands, therefore the release of milk during breastfeeding

Question 13

ADH

Answer 13

stimulates the kidneys to remove water from the urine being formed by increasing permeability of DCT and CDs. i.e. increased water reabsorption, and can also cause, in high concentrations, vasoconstriction of arterioles. (hence why it can be called vasopressin)

Question 14

Pineal gland

Answer 14

releases melatonin, which is involved in the regulation of sleep patterns

Question 15

Thyroid gland

Answer 15

releases thyroxine, which controls body metabolism, and is often involved in increasing the body’s internal temperature

Question 16

Parathyroid glands

Answer 16

release parathyroid hormone, which increases calcium levels in the blood and phosphate excretion in the urine

Question 17

Thymus

Answer 17

releases group of hormones called thymosins, which influence the maturation of T-lymphocytes

Question 18

Adrenal Medulla

Answer 18

releases adrenaline, which helps to prepare the body for a situation involving rigorous exercise and noradrenaline, which has similar effects to adrenaline, in particular increasing the rate and force of the heartbeat

Question 19

Adrenal Cortex

Answer 19

releases cortisol, which promotes normal metabolism, helping the body to withstand stress and repair damaged tissues, and aldosterone, which increases the amount of potassium and decreases the amount of sodium in the urine.

Question 20

Pancreas

Answer 20

releases:
insulin, which reduces the amount of glucose in the blood by promoting the uptake of glucose from the blood by cells; in the liver, it causes the conversion of glucose to glycogen and fat, in the skeletal muscles, it causes the formation of glycogen from glucose, and in adipose tissue, causes glucose to be converted into fat
glucagon, which does the opposite to insulin, mainly by promoting the breakdown of glycogen to glucose in the liver, and the breakdown of fat in the liver and adipose tissues