12U Biology Endocrine System

Endocrine system

regulates growth, development, tissue function, metabolism, sexual function and reproductive processes

Hormones

chemical messages-send messages from one part of the body to the next

Endocrine hormones

produced by glands and secreted directly into the blood

Exocrine hormones

glands that secrete substances through ducts

Steroid hormone

made from cholesterol, soluble in fat, but not water (sex hormones and cortisol)

Protein hormone

composed of amino acids, soluble in water (insulin and GH)

Hypothalamus

regulates the pituitary gland through nerves

action of steroid hormones

1. diffuses from cell

2. diffuese into target cell and attaches to receptor molecule

3. hormone receptor complex moves into the nucleus and attaches to DNA

4. a gene activated in the DNA initiates protein synthesis

action of protein hormones

1. hormone is released from cell

2. hormone attaches to receptor site on the outside of cell membrane

3. the hormone-receptor complex promotes the formation of cyclic AMP

4. cyclic AMP acts as a messenger to activate other enzymes to do their job

Anterior pituitary galnd

1. Prolactin

2. GH

3. TSH

4. ACTH

5. FSH & LH (gonadotropins)

Prolactin

mammary glands; milk production

GH (growth hormone)

cell division, protein sythesis and bone growth; responsible for controlling metabolism- acts by binding to muscle cells and other tissues releasing IGF

TSH (thyroid-stimulating hormone)

stimulates the scretion of throid hormones and the growth of the thyroid gland

ACTH (adrenocorticotropic hormone)

triggers hormone/glucocorticoids scretion in adrenal cortex

FSH (folical stimulating hormone) and LH (luteinizing hormone)

gonadotropins- regulate the gonads/ secretion og sex hormones

oxytocin

promotes uterine contraction

thyroid gland

1. calcitonin

2. T4, T3

cA

Posterior pituitary gland

1. ADH

2. oxytocin

ADH (antidiuretic hormone)

increases blood volume and pressure by increasing water reabosorption in the kidneys when increase in sodium detected

Glucagon

Promotes conversion of glycogen to glucose

Insulin

Increases the permeability of cells to glucose

Medulla

Inside; secretes epinephrine and norepinephrine. These can act as hormones or neurotransmitters

Adrenal Cortex

Releases aldosterone (osmoregulation)

Pineal Gland

Responsible for biorhythms

Secretes melatonin

Long Term Stress Response

1. Hypothalamus releases a hormone which stimulates the pituitary to realize ACTH

2. ACTH travels through the blood to the adrenal cortex and stimulates it to release mineralocorticoids and glucocorticoids

3. These hormones are carried to the liver and muscles where amino acids are converted into glucose or used in protein synthesis