Chapter 9 Endochrine System Flashcards
Endochrinology
Scientific study of glands/cells and hormones
Hormones
Chemical messengers
Endochrine System
communicates with hormones
releases hormones into blood but only target cells respond
causes change in metabolic activites of target cells
reacts slowly (seconds to days)
may continue long after stimuli stops
Nervous system
communicates with electrical impulses and neurotransmitters
releases neurotransmitters at synapses with target cells
relatively local, specific effects, muscles contract or glands secrete
reacts quickly
stops quickly
Major Endochrine Glands
Hypothalmus
Pituitary
Thyroid
Pancreas
Adrenal
Gonads: ovaries and testes
Pituitary Gland
Growth hormone secreted by gland
directs growth of skeletal muschel and bone
Homeostatic imbalances of Growth Hormone
Pituitary dwarfism
gigantism
acromegaly
Pituitary Dwarfism
hyposecretion of GH during childhood
person max 4ft
Gigantism
hypersecretion of GH during childhood
extremely tall
Acromegaly
hypersecretion of GH in adults
facial bones, hands and feet enlarge
Oxytocin
stimulates powerful contractions during childbirth
pitocin: synthetic oxytocin used to induce or hasten labor
Thyroid Gland
Thyroxin- major hormone
stored in colloid of follicles
regulates body metablolism, important for normal development of nervous system
Goiter
enlargement of thyroid gland when body
deficient in iodine
Homeostatic imblances of thyroxine
Cretinism
Myxedema
Cretinism
hyposecretion of thyroxine in children results in mental retardation
Myxedema
Hypothyroidism in adults results in mental and physical sluggishness
Pancreas
Insulin
secreted by beta cells decreases blodd glucose levels
Glucagon
secreted by alpha cells raises blood glucose levels between meals
work together to keep blood glucose levels relatively constant
Homeostatic Imbalances of Insulin
Diabetes
Type 1-juvenile diabetes
beta cells destroyed by immune system
decreased insulin
Type 2-adult onset
tissues have a decreased responsiveness
to insulin
