ENDOCRINE Flashcards
Endocrine glands (location + alternate names)
- Pineal g.
- Hypothalamus
*Infundibulum (connects PPG to HT) - Pituitary g. (hypophysis)
- Anterior p.g. (adenohypophysis)
*Pars intermedia (between APG and PPG) - Posterior p.g. (neurohypophysis)
- Anterior p.g. (adenohypophysis)
- Thyroid + Parathyroid g.
- Pancreas
- Adrenal gs. (suprarenal gs.)
- Testes or Ovaries
- *Placenta (only during pregnancy)
Pituitary g. tumour (name, effect, symptoms, removal)
pituitary adenoma –> can cause a depression in the hypothalamus (called mass effect)
symptoms: visual defects (optic chiasm, bitemporal hemianopia) and headaches
removal: transsphenoidal hypophysectomy, remove tumour through sphenoid sinus (up nose), replace with fat and seal in with cartilage and glue
Bone where pituitary is located (name, main structures)
Sphenoid bone:
- Turk’s saddle/sella turcica
- tuberculum sellae
- hypophyseal fossa (pituitary g. sits here)
- dorsum sellae
Pituitary g. blood supply (for each + main issue)
- Ant: superior hypophyseal artery –> hypophyseal portal veins –> ant. hypo. v. (AHV)
- Post: inferior hypophyseal artery –> post. hypophyseal veins
issues: BP extremely low in AHV, if BP drops in body (eg: extreme blood loss) it’s easy for blood flow to stop here, APG can die –> panhypopituitarism
Pituitary gland development
anterior: outgrowth of the ectoderm of the roof of the mouth (pars distalis)
posterior: outgrowth of the ectoderm at the base of the hypothalamus (pars nervosa)
pars intermedia: seperates ant. and post.
(develops at 5 - 16 weeks of pregnancy)
*W13, the pituitary, 3:00
3 types of hormone communication (name, steps, examples)
Endocrine: hormones from endocrine cell –> blood –> cell (trigger effect) –> detach (effect dissipates)
Paracrine: hormones from paracrine cell –> nearby cells
eg: prostaglandins (inflammation, blood flow + clots, induce labor), Nitric Oxide (dilates BV, reduce BP)
Autocrine: hormones from autocrine cell –> effects same cell
eg: IGF-1 sometimes
Hunger signalling hormones
- Leptin: from fat cells when ‘full’ –> signal hypothalamus –> stop eating
- Ghrelin: from empty stomach –> signal hypothalamus –> start eating
Hydrophilic hormones (circulation steps)
- water soluble, travel through blood
- bind to extracellular receptors
- message must be transduced to effect the cell
- *leads to production of second messengers (eg. cAMP, IP3)
- second messengers alter cellular function (one H hormone can cause many SM)
- SM concentration fluctuates depending on H hormone receptor binding
*some hormones (eg: insulin) do not need second messengers
Lipophilic hormones (circulation steps)
(all steroids are lipophilic)
- travel through blood
- pass through phospholipid bilayer (intracellular or even intranuclear)
- bind to intracellular receptors
- hormone-receptor complex binds to DNA
Tropic vs Non-tropic hormones
Stimulating: go to other endocrine glands to stim. production of another hormone vs Direct: go to desired cell to incur hormonal effects
hormones for long bone growth
- hGH stimulates formation of new cartilage at epiphyseal line
- growth plate is ‘closed’ by testosterone and estrogen (puberty)
development of lactating (active) mammary glands
high levels of estrogen and progesterone trigger activation
- that’s why breaks are needed from hormonal birth control pills
Hormones produced in Hypothalamus
to APG
- TRH: thyroid releasing hormone –> produce TSH
- CRH: corticotropin releasing hormone –> produce ACTH
- GnRH: gonadotropin releasing hormone –> produce FSH and LH
- GHRH: growth hormone releasing hormone –> produce hGH
- GHIH: growth hormone inhibiting hormone (somatostatin) –> inhibit hGH AND TSH
to PPG
- PIH: prolactin inhibiting hormone (dopamine) –> inhibit PRL
to PPG
- Oxytocin
- ADH: antidiuretic hormone (vasopressin)
(8 total)
Main hormones produced in Anterior pituitary
Tropic:
- FSH: follicle stimulating hormone - promotes follicle and sperm development
- LH: luteinizing hormone - promotes ovulation, sex steroid production
- ACTH: adrenocorticotropic hormone/corticotropin - promote production of glucocorticoids
- TSH: thyroid stimulating hormone - stims thyroxin release
Non-tropic:
- PRL: prolactin - stimulates milk production in F
- hGH: human growth hormone - promote protein synthesis + bone growth + increase blood glucose
Pars intermedia:
- MSH: melanocyte stimulating hormone - increase pigmentation
(FLAT PeG M)
Regulation of prolactin
Hypothalamus:
- TRH promotes PRL (weak)
- PIH inhibits PRL
APG:
- PRL produced
Breasts:
- lactation
- suckling inhibits PIH
Meds:
- domperidome (dopamine receptor blocker) inhibits PIH
