Exam 3- Hypothalamus Flashcards
how are neurohormones transported from the hypothalamus to the anterior lobe of the pituitary?
hypothalamic-pituitary portal system
what peptide hormones are released from the posterior pituitary?
oxytocin
antidiuretic hormone (ADH)
what does antidiuretic hormone (ADH) regulate?
extracellular fluid volume and osmolarity
does antidiuretic hormone increase or decrease renal reabsorption of water?
increases it
what are oxytocin’s main effects on?
contraction of uterine smooth muscle
mammary gland myoepithelial cells
what do tropic hormones do?
regulate release of other hormones and development and growth of target glands
what type of hormones does the anterior pituitary release?
all tropic hormones except prolactin
what is episodic hormone secretion?
pattern of secretion with regular intervals, leading to oscillations in blood levels
what are two hormones that follow episodic hormone secretion?
follicle stimulating hormone (FSH)
luteinizing hormone (LH)
what innervates melanotrope cells in the intermediate pituitary lobe?
hypothalamic dopaminergic neurons
what regulates the secretions of the anterior pituitary endocrine cells?
hypothalamic hormones delivered to anterior pituitary directly and in high concentrations
where is oxytocin released (what areas of brain)?
nerve endings in parts of brain associated with bonding and trust
in thyroid stimulating hormone, luteinizing hormone, and follicle stimulating hormone, what are their subunits and which one conveys specificity?
alpha and beta
beta conveys specificity: alpha is same for all three hormones
what peptide hormones does the posterior pituitary release?
oxytocin
antidiuretic hormone
how does antidiuretic hormone regulate extracellular fluid volume and osmolarity?
increases number of aquaporins in distal tubule and collecting ducts
how does dopamine affect milk?
facilitates milk let-down by causing contraction of myoepithelial cells
are all of the peptide hormones released from the anterior pituitary tropic?
no, not prolactin
what does cortisol and corticosterone stimulate?
production steroid hormones from adrenal cortex
what do estrogen and inhibin do?
stimulate production sex hormones and growth and maturation of germ cells
what do thyroxine and triiodothyronine do?
stimulate production of thyroid hormone and growth of thyroid gland
are all hypothalamic hormones peptide hormones?
yes
what is a circadian secretion pattern and what hormone(s) follow it?
regular oscillations with a cycle of 24 hours
some pituitary hormones, eg ACTH
what is the primary secretory product of the intermediate pituitary lobe in most species?
melanocyte stimulating hormone
how are posterior pituitary hormones released?
stored in secretory vesicles as prohormones, then cleaved into hormones when transported to nerve terminal for release
what is the half life of posterior pituitary hormones?
3-5 minutes
what are the anterior pituitary hormones and which ones are tropic?
follicle stimulating hormone: tropic
luteinizing hormone: tropic
adrenocorticotropic hormone: tropic
thyroid stimulating hormone: tropic
growth hormone: tropic
prolactin
what is the structure of the ACTH family of hormones (those from POMC: ACTH, beta-endorphin, melanocyte stimulating hormone)?
large peptide prohormone that has sequences that are biologically active when cleaved off
what two hormones control growth hormone secretion?
growth hormone releasing hormone
somatostatin
how is POMC production suppressed?
hypothalamic dopaminergic neurons innervate melanotrope cells
dopamine binds to melanotrope cells
