Homeostasis and Endocrine System Flashcards
Definition of homeostasis
Maintenance of a constant internal environment
What is the internal environment regulated by
Autonomic nervous system
Endocrine system
What do positive feedback do
Amplify the change, deviation from the norm is not corrected
Give examples of positive feedback
Oxytocin for uterine contraction
Blood clotting
What is the endocrine system made up of
Hormones
Glands
Target cells
Communication
Give examples of endocrine glands
Testes
Ovary
thyroid gland
placenta
adrenal gland
hypothalamus
pituitary gland
What do adrenal glands release
cortisol and medulla adrenaline
Difference between endocrine and exocrine
Endocrine - no excretory ducts, hormones released locally/into blood, target cells
Exocrine - excretory duct, secretory products released through ducts
What produces thyroxine
thyroid gland
What stimulates thyroxine and form where
TSH - thyroid releasing hormone from pituitary gland
What regulates thyroxine and where from
TSH - thyrotropin releasing hormone from hypothalamus
Thyroxine target cells?
All cells
What are some major effects of thyroxine
Increase body temp + basal metabolic rate
Regulates growth hormone production
Calcium ion metabolism
Gonadal function
Lactation
Where is parathyroid hormone made
Parathyroid gland
What stimulates PTH
Low plasma calcium ion levels
Target for PTH
Bone, kidney (distal tubules)
Major effects of PTH
Stimulates osteoclast breakdown to release Ca2+
Stimulate distal tubule of kidney to reabsorb Ca2+
Stimulates vitamin D production by kidney
Stimulate small intestine to increase absorption of Ca2+
Where is calcitonin made
Thyroid gland
What stimulates calcitonin
increase calcium ion levels
Target for calcitonin
Bone, kidney
Where is melatonin made
Pineal gland
What stimulates melatonin
Lack of daylight - light suppresses melatonin production
Target for melatonin
Brain
Major effects of melatonin
reproduction - GnRH production
