Endocrine System Flashcards
endocrine system characteristics
- has ductless glands and composed of endocrine tissues
- secretes hormones into blood
target cells
any cell w/ receptor for specific hormone
hormone classes
steroid hormone, hormones derived from amino acids & peptide+protein hormones
steroid hormones
- derived from cholesterol
- has lipids: hydrophobic, lipid soluble
hormones derived from amino acids
- tyrosine: amino acids used to make thyroid hormones (T4)
- tryptophan: amino acid makes serotonin + melatonin
peptide & protein hormones
- from chains of amino acids
- hydrophilic, water soluble
- ex: oxytocin + growth hormone
pituitary glands characteristics
- suspended by hypothalamus
- located at sella turcica o sphenoid bone
- highly vascular (allows secretions of hormones)
- composed of the anterior + posterior pituitary
what secretes from the hypothalamus?
regulating hormones are secreted
what do the regulating hormones do?
regulate the secretion of hormones from the pituitary gland
anterior pituitary gland function
secretes hormones that affect growth, metabolism + reproduction
hormones anterior pituitary gland secrets:
- follicle stimulating hormone (FSH): reproduction
- leutinizing hormone (LH): reproduction
- adrenocorticotropic hormone (ACTH): stimulates secretion of steroids from adrenal glandss
- thyroid stimulating hormone (TSH): stimulates secretion of thyroid
- prolactin (PRL): milk formation
- growth hormone (GH): growth + metabolism
posterior pituitary gland
- ext. of hypothalamus formed from nervous tissue
- secretes hormones produced in hypothalamus
hormones posterior pituitary gland secretes:
- oxytocin: stimulates uterine contractions
- antidieuretic hormone (ADH): vasopressin–stimulates water reabsorption in kidney
thyroid gland characteristics
- located on superior surface of trachea below larynx
- shaped like butterfly
- composed of 2 diff cells (follicles + parafollicular)
thyroid gland cell types follicles:
- follicular epithelial cells
- produce thyroxine (T4) hormone
- controls metabolism, growth + development
- produced in lumen of gland + secreted from follicular cells
thyroid gland cell types parafollicular cells:
- surround follicle
- secrete calcitonin
what does calcitonin do?
- stimulates calcium uptake by bone, decreasing plasma calcium
- builds bone matrix (osteoblasts)
parathyroid gland
- consists of 4 glands on posterior surface of thyroid gland
- produces parathyroid hormone (PTH)
functions of PTH
- acts to increase calcium levels
- stimulates breakdown of bone matrix (osteoclasts)
how can PTH increase calcium levels?
- decreasing calcium excretion from kidney
- increasing vitamin D activation in kidney
function of vitamin D
increase calcium reabsorption in intestine
adrenal gland basic characteristics
- located on superior surface of kidney
- 2 glands (adrenal cortex + adrenal medulla)
adrenal cortex
- secretes steroid hormones
- 3 layers (zona glomerulosa, fasciculata, reticularis)
zona glomerulosa
- secretes mineralocorticoids: predominantly aldosterone (regulates salt balance)
