Endocrine System

Functions of Endocrine System

produce hormones that monitor/coordinate body activities

Amino Acids

made of proteins (all but adrenal cortex/sex glands)

Steroids

made from cholesterol (lipids) - adrenal cortex hormones and sex glands, most in -sterone

1. negative feedback

(most common, corrective) - cause target tissue to produce more, circulates in blood sensed by the brain causing it to stop producing

2. positive feedback

(keep going) - hormone response produces more hormone

3. rhythmic pattern

hormones released on set schedule

hypothalamus

sends hormones and nerve implants that control secretion of pituitary, produces hormones, two stored in posterior lobe of pituitary

pituitary/hypophysis gland “master gland)

* produces hormones that regulate secretion of other glands
* two lobes that together produce 8 hormones

anterior: 6 hormones

posterior 2 hormones (made in hypothalamus and stored here)

anterior 1: growth hormone

promotes growth all body tissue

anterior 2: thyroid

stimulating hormones (thyroidtrophic): stimulates secretion of the thyroid to release hormones

anterior 3: Adrenocorticotropic hormone

stimulates secretion of adrenal cortex and growth

anterior 4: prolactin

stimulates production of milk (mammary glands)

anterior 5: follicle

stimulating hormone, stimulates growth of follicles, sperm-cells/testes

anterior 6: luteinizing hormone

stimulating hormones (males)

* development of corpus luteum/ovulation/stimulate testosterone secretion in males

posterior 1: antidiuretic hormone

kidney reabsorbs water into blood during urine formation

posterior 2: oxytocin

causes contraction of uterine muscles during labor, eject milk from mammary glands

pineal body

pea sized, located deep within brain - regulates mood, influence sleep cycle, sexual development

thyroid (largest endocrine gland)

increases metabolic rate physically and mentally

parathyroid

posterior capsule of thyroid

* secretes parathyroid hormone: raise level calcium in blood
* causes liver modify vitamin D into calcitriol: hormone works with parathormone: increase blood calcium

adrenal glands

produce 30 hormones

adrenal cortex

produces:

* mineralcorticoids: regulate electrolyte balance
* glucocorticoids: help w/ starvation, increasing glucose in times of stress, suppress inflammation response

adrenal medulla

response to stress, increase heart rate, BP, blood sugar, decrease blood flow to internal organs for flight or fight

pancreas

islets of langerhans that secrete


1. insulin by beta cells (feasting): lowers blood sugar, stimulates manufacture of amino acids into protein, store fat
2. glucagon by alpha cells (fasting): increase blood sugar

gonads (sex organs)

ovaries and testes produce hormones to

* develop sexual characteristics
* maintain reproductive organs
* bone and muscle growth and repair

male sex hormone/androgen

* testosterone - stimulates growth of the testes and promotes secondary sec characteristics

female sex hormones

* estrogen: stimulates growth of the testes and promotes secondary sex characteristics
* progesterone: prepares the uterus lining for implantation of the fertile egg, aids in maintaining pregnancy