Lecture 14: Endocrine System Flashcards
what is the function of the endocrine system?
- secrete hormones into the bloodstream
- works with the nervous system to control organ activity
what is the thyroid gland?
outgrowth from floor of pharynx
- homologue of endostyle
what are the 2 main hormones of thyroid gland?
thyroxine and triiodothyronine
- contain iodine and influence metabolism
what is the thyroid structure of cyclostomes/teleosts
dispersed masses of follicles
how does thyroid promote metabolism?
- TH elevate oxygen consumption and heat production in endotherms
- but an oveproduction of TH causes grave’s disease
describe moulting
replacement of hairs, feathers, or layers of epidermis
describe reproduction role of TH
promote gonad maturation
what are parathyroid glands
paired glands near the thyroid that have developed from pharyngeal pouches
what is the function of parathyroid glands?
secrete PTH which promotes release of calcium in the bloodstream
what are adrenal glands?
paired structures located near the kidneys
what are the two tissue types of adrenal glands?
- adrenocortical tissue: develops from sphlanchnic mesoderm and secretes corticosteroid hormones
- chromafin tissue: develops from neural crest cells and secretes adrenalin and noradrenaline hormones
what is the function of adrenocortical tissue
regulates carbohydrate metabolism, sexual dev. and water and sodium balance
what is the function of chromaffin tissue
promote short term fight or flight response to threats
what is the adrenal gland tissue arrangement of cyclostomes and teleosts?
adrenocortical and chromaffin tissues dispersed near the kidneys
what is the adrenal gland tissue arrangement of chondrichthyans?
adrenocrotical is in glands, while chromaffin is dispersed
what is the adrenal gland tissue arrangement of lissamphibians?
organised or scattered
what is the adrenal gland tissue arrangement of reptiles?
mingled within distinct glands
what is the adrenal gland tissue arrangement of mammals?
adrenocortical tissue external to chromaffin tissue
pancreas: what is exocrine
secretion of digestive enzymes via ducts
pancreas: what is endocrine
secretion of hormones into bloodstream from islets of langerhans
what hormones do islet of langerhans produce
insulin, glucagon, somatostatin, pancreatic polypeptide
what is the pancreatic structure of cyclostomes/teleosts?
islets outside of exocrine
what is the pancreatic structure of chondrichthyans/tetrapods
islets within exocrine
what is the pancreatic structure of birds
islets form distinct pancreatic lobes
where is the pituitary gland and what does it do?
below the hypothalamus; releases hormones
what is the anterior lobe of the pituitary and what does it do?
adenohypophysis; secretes hormones from buccal cavity
what is the posterior lobe of the pituitary and what does it do?
neurohypophysis; secrete neurohormones from hypothalamus
adenohypophysis hormones: what does growth hormone do?
regulates growth
adenohypophysis hormones: what does thyroid stimulating hormone do?
promotes release of hormones from thyroid
adenohypophysis hormones: what does corticotropins do?
stimulate adrenal gland
adenohypophysis hormones: what does gonadotropins do?
promote maturation of gametes
adenohypophysis hormones: what does melanophore do?
influences pigmentation of skin
adenohypophysis hormones: what does prolactin do
various; tail regeneration in lizards or brooding in birds
neurohypophysis hormones: what does vasopressin do?
promotes vasconstriction and elevated blood pressure
neurohypophysis hormones: what does oxytocin do?
promote contraction in reproductive organs
