physio

• -ductless glands
• -specific target cells

• -regulate organic metabolism
• -regulate eater and electrolyte balance
• -induces heat to help body cope with stresses
• -promote growth and development
• -control reproduction
• -regulate RBC production
• -CV & GI control

• -1 gland makes & secretes multiple homones
•     ex: pituitary
• -1 homone from multiple glands
•   -ex: somatostatin
• -1 homone goes to multiple targets 
•    ex: vasopressin
• -cyclic secretion patterns
• -multiple hormones go to the same target
• -insulin vs. glucagon

• -same chemical messanger can be either nt or homone
• ex= NE
• -some organso of endocrine system perfrom non endocrine functions
• ex= testes, pancreas

the amount of free homrone in plasma

ex: as secretion increases, amount of homone increases

• ex: thyroid hormone
• -T3 more potent than T4

• lipophilic hormones
• -unbound H is monitored

• liver, kidney,etc.
• clearance

-output conteacts a change in input

• -amplifies intital effect of hormone
• -a "vicous cycle"

ex: blood clot, allergic reaction, childbirthing + breastfeeding

produce sudden increase in hormone secretion

ex: adrenaline rush

• -hormones that fluctaute over 24 hours
• -happens on a daily activity

• ex: melatonin
• -melatonin is highest at the night time 

• 1*= decrease in secretion due to glandular abnormality
• =genetic, dietary, chemical toxicity, immunologica, 2nd to disease process, Iatrogenic ( some other disease but physicans medicine causes gland not to function), idiopathic
• 2*= decrease in secretion as a result in decrease in stimulus by trophic hormone

• 1*=increase in secretion due to glandular abnormality
• 2*=increase in secretion due to increase stimulation of gland
• -tumors, immunological factors ( antiboitics that mimic TSH), substance abuse

• 1. grow
• 2. secrete its hormone

• -lack of receptos
• ex: testicular feminization syndrome=
•           -external genitalia looks female
•          - short blind puch vagina
•          - no unterus, no ovaries, no fallopian tubes
•          - testes located in abdomen (not descended)
• -lack of cellular component in response pathway
• ex: enxyme, 2nd messanger

• -so miuch homrone the cell stops responding to it
• ex: insulin insensitivity, individuals eat carbs all the time & insulin is chronically high

(-more internalization of receptor and u cannot replace empty receptors to membrane, so u lose response to insulin & you have chronic high glucose)

-one hormone must be present for full effect of another hormone

• several hormones are complimentary
• -combines effect greater than that of one

ex= progesterone prevents estrogen from causing uterine contactions during pregancy

• -body temperature
• -thirst and appetite
• -uterine contraction & milk ejection
• -ANs coordination center

• Bridge to endocrine:
• -stimulates or inhibts AP hormones secretion via releasing or inhibting hormones
• -synthesizes P.P. hormones

• -has a 24 cycle for body functions
• ex: temp, gene expression, behavior, hormone secretion

• Suprchiasmatic nucleus (SCN)
• -cluster of neuron cell bodies above optic chiasm
• -input from each eye (establishment of inherent daily rthyms)

• -"Self starting" generes of SCN neurons = synthesis of proteins
• **see synoposis made in notes

• -SCN is reset dauly by external cues (light intensity)
• **pineal gland secretes melatonin to synchronize

-if not adjusted, individuals circardian rhyms falls out of sync with day and night

• -different than for vision
• -specialized retinal ganglion cells
• -Pineal gland responds with cycle of melatonin (24 hr cycle)

• -idolamine
• -secreted during periods of darkness
• -proposed roles=
• -can induce natural sleep, inhibits sex hormones, (puberty initated by melatonin levels), (in other species: hibernation, seasonal breeding), birth control (high levels shut down ovulation), antioxidant, slows againg process, enhances immunity (also slows regression of thymus)

-Anterior Lobe: true glandular tissues "Adenohypophysis"

• -Posterior Lobe: extension of hypothalamus "Neurohyphophysis"
•    

• -Suproptic Nucleus SON
• -Paraventricular Nucleus PVN

• -terminals in posterior lobe
• -SON & PVN contain neurons that produce peptide hormones (but only one hormone produced per cell!)
• -Hormones:
•     - Vasopressin & Oxyctocin

• Release Triggered By:
• -hypothalamic osmoreceptors
• -left atrial volume receptors
• -acute infection, pain, trauma (inappropriate H20 retention)

• Targets:
• -kidney
• -arteriolar smooth muscle (**Crucial during hemorrhage)

• Released by:
• -stimulation of cervical mechanoreceptors
• -stimulations of mechanoreceptors in nipple
• Actions:
• -at uterus, decrease threashold potentioal
• -at breast, increases myoethithial tone
• Also influences: maternal bleeding

• -hypophsiotropic hormones
• -secreted in pulses

hypothalamic releasing hormones= stimulates release of hormones from anterior piuitray cells

hypothalamic inhibiting hormones= inhibits release of hormone from anterior pitiuitary

• -capillary to capillary link
• -direct route from hypothalamus to pituitary 

(neurosecretory neurons terminate on the capillares of portal system)

• -can be either stimulatory or inhibitory
• -neural connections with other portions of the brain
• -environment factors
• -chemical signals: hypothalamic regions unprotected by blood brain barrier

• suppress secretion of trophic hormones that is driving it
• -negative feedback control: once its hormonal signal is activated, its secretion does not continue unabated

• -Lactotropes: Prolactin (protein similar to GH)
• -Somatropes: Growth Hormone 
• -Thyrotropes: TSH
• -Corticotropes: ACTH
• -Gonadotropes: FSH & LH 

• -FSH & LH
• -ACTH
• -GH
• -TSH

• -under influence of growth hormone
• -net synthesis of proteins
• -increase in growth of long bones
• -increase in # of soft tissues

• -genetics
• -diet
• -freedom from disease & stressful environment
• -normal levels of growth influencing hormones:
•    **thyroid hormone, insulin, sex hormones

• Fetal growth:
• -placental hormones
• -GH not involved!!!
• -genetic/environmental factors
• Children:
• -postnatal growth spurt (1st 2 yrs)
• -pubertal growth spurt ( 11 yrs female, 13 yrs male)
• **Both T and E2= halt bone growth @ end of puberty 

• -GH is most abundant AP hormone secreted
• ---binds directly to target tissues: adipose, skeletal muscles, liver

**also stimulates protein synthesis