Download Body Systems - Bishop Ireton High School

Endocrine
Function
 Produce hormones-released into bloodstream
 Maintain homeostasis
 Works through negative feedback: Obtaining a desired
response to a hormone inhibits further production or
secretion of that hormone.
 Example- when blood glucose levels are high, insulin is
produced to remove glucose from blood. Glucose is
stored in the cells. When blood glucose levels are low,
glucagon is produced to cause cells to release stored
glucose into the blood. When desired level is reached,
hormone production is turned off.
 Other example of negative feedback- when body
doesn’t take in enough water it becomes dehydrated.
Anti diuretic hormone(ADH) will be produced to tell
large intesine to absorb as much water as possible.
 Hormone- substance produced in one area (like a
gland) that has an effect in another area or target cell.
 Glands produce and release hormones into blood
stream.
2 types of hormones
 Steroid-fat soluble- move through cell membrane
easily
 Nonsteroid- need a receptor on cell membrane to bind
to it. This sends signal inside cell that causes another
enzyme to act as messenger to cause effect.
Hypothalmus-in brain
 Master gland- controls nervous system and endocrine
system.
 Will stimulate pituitary gland to release its own
hormones to stimulate other glands.
Pituitary Gland-in skull
Pituitary Gland
Hormone
Action
Posterior
ADH
Kidneys reabsorb water
Posterior
Oxytocin
Uterine contactions and milk production
Anterior
FSH
Production of egg and sperm
LH
Prepares uterus for implantation
TSH
Release thyroxin from thyroid
GH
Protien synthesis in cells
Prolactin
Milk production
ACTH
Stimulates adrenal cortex
Thyroid Gland
 In base of the neckRegulates boby’s metabolism by
production of thyroxine
 Too much- hyperthyroidism- weight loss, nervousness
 Too little- hypothyroidism- weight gain, lethargy
Parathyroid Gland
 Located behind thyroid
 Parathyroid Hormone regulates calcium levels
Adrenal Gland-Cortex
 Aldosterone- regulates Na reabsorption and excretion
of K
Pancreas
 Maintains blood glucose levels
 Insulin lowers BG.
 Glucagon increases BG.