deck_685208 Flashcards
Steroid hormone
cholesterol derived-Gonadal (estrogen, Testosterone) -> secreted by cells of ovaries and testes-Adrenocortical (aldosterone, cortisol) -> secreted by cells of adrenal cortexNeed protein carriers
Peptides/protein hormones
Dissolve in blood don’t need carrier proteins (but most have them)secreted from:Hypothalamus, pituitary, thyroid, parathyroid, Pancreas, GI tract, Respiratory System
Amino Acid Hormone
- Thyroid Gland (thyroid hormones)- Adrenal medulla (nor/epinephrine)- Dissolve readily in blood
Pituitary Gland parts
Hypothalamus -> median eminence -> infundibulum -> Posterior and anterior pituitary (seated in the sella turcica of sphenoid bone)- Posterior pituitary: infundibular stalk -> pars nervosa- Anterior Pituitary: Pars tuberalis, Pars intermedia, Pars distalis
Anterior Pituitary embrology
: Evagination of oropharynx ectoderm toward Rathkes pouch
Posterior Pituitary embryology
invagination of neural ectoderm infundibular process
Anterior pituitary
(adenohypophysis)- Pars distalis (anterior lobe)- Pars Tuberalis- Pars Intermediavascular connection to Hypothalamusregulates other endocrine glands (tropic hormones) and some nonendocrine tissues
Posterior Pituitary
- Infundibulum -> continuous with median eminence… contains neurosecretory axons forming hypothalamohypophyseal tracts- Pars Nervosa (posterior lobe)Neurological connection to hypthalamous -> stores hypothalamus neurosecretions stores and secretes ADH and Oxytocin
Herring Bodies
Store and secrete hypothalamus neurosecretions in the posterior pituitary
Neuronal Cell bodies of Hyp.
supra-optic nucleus - synthesize and secrete primarily ADHParaventricular nucleus - synthesizes and secretes primarily oxytocin
Anterior Pituitary cell types
Basophils• Gonadotrophs - FSH and LH in response to GnRH• Thyrotrophs - Thyrotopin/TSH in response to TRH• Corticotrophs – ACTH in response to CRHAcidophils•Somatotropes – release GH/Somatotropin stimulated by GHRH•Mammotrops/lactotropes – prolactin in response to TRH
Pituitary gland blood supply
Superior Hypophyseal artery • From internal carotid -> supplies median eminence, pars tuberalis and infundibulumInferior Hypophyseal artery• From Internal Carotid -> supply pars nervosa• Capillary net work in hypothalamous• Capillary net work in anterior pituitaryHypothalamo-hypophyseal portal system
hypothalamo-hypophyseal portal system
carries neuroendocrine secretions and hypothalamic nerves from median eminence to pars distalisin particular… carries hypothalamic releasing hormones
pituitary regulation
2 levels of inhibition: 1) Hormone production in the pituitary gland is inhibited 2) hypothalamic releasing hormones are regulatedPrimarily negative feedback
Pineal Gland
regulates daily body rhythm