Download Endocrine System Notes

The Endocrine System
I.
II.
Endocrine Glands
A. “Ductless” Glands
B. Pass their secretions directly into the bloodstream
Hormones
A. “Chemical Messengers”
B. Regulate chemical reactions in the body, bodily functions
III.
Thyroid Gland
A. Located at the base of the neck, just below Larynx
B. Hormone – Thyroxin
C. Controls metabolism
D. Too little thyroxin may lead to sluggishness, weight gain
E. Too much thyroxin may lead to hyperactivity, increased appetite,
no weight gain
IV.
Parathyroid Gland
A. Four small pea-shaped glands on the backside of the Thyroid
B. Hormone – parahormone specific to the balance of calcium
V.
VI.
VII.
Adrenal Glands
A. Located on top of the kidneys
B. Hormone – Adrenaline
C. “glands of combat” - fight or flight response
D. Controls body’s reaction to stress – increase sugar levels/energy
E. Also controls levels of salt and water in the body
Islets of Langerhans
A. Located throughout the Pancreas
B. Hormone – Insulin
C. Regulates amount of glucose (sugar) in the blood
D. If gland does not operate correctly - Diabetes
Thymus Gland
A. Located behind top of sternum (breast bone)
B. Hormones – Thymosin, Thymopoietin
C. Important in the normal development of the immune response
D. Large in infants and children; begins to shrink by adolescence
and adulthood.
VIII.
Ovaries – Female only – inactive until Puberty
A. Two glands in pelvic region
B. Hormones - Estrogen, Progesterone
C. Primary function as an organ to store ovum
D. Estrogen controls female characteristics – development of
breasts, widening of pelvic bones, menstruation
E. Progesterone secreted during pregnancy
IX.
Testicles/Testes – Male only – inactive until Puberty
A. Two glands in scrotum
B. Hormone – Testosterone
C. Primary function as an organ to produce sperm
D. Testosterone controls male characteristics – growth of body hair,
widening of shoulders, muscle development, enlargement of
larynx (Adam’s Apple) and deepening of voice
X.
Pineal Gland
A. Located in the brain
B. Hormone - Melatonin
C. Regulates sleep, hibernation (animals), aging – “sociological” or
“biological clock”
XI.
XII.
Hypothalamus
A. Located in the brain
B. Controls many bodily functions including the release of hormones
from the pituitary gland
C. Regulates body temperature, thirst, and hunger
D. Site of emotions and the effect emotions can have on the body
Pituitary Gland
A. Located at the base of the brain
B. Hormone – Human Growth Hormone (HGH)
C. Regulates body’s growth and development
D. Also produces several other hormones
E. Referred to as the “Master Gland” – controls the functioning of
many other glands/organs – thyroid, adrenal, kidney