Online Reading: Neuroendocrinology Flashcards
Define a HORMONE
- Substance prod by 1 tissue which enters the bloodstream to act on another tissue & prod an effect
- Must be released in 1 location, be transported via circulatory system, & act elsewhere
Describe how the anterior pituitary regulates its targets.
ANTERIOR PITUITARY:
- regulates the target glands
- is regulated by the hypothalamus
= via NEGATIVE FEEDBACK
- ie) Hypothalamus rel GnRH to anterior pituitary
–> Anterior pituitary rel Gonadotropins to testes
–> Testes prod testosterone
… - Testes prod enough testosterone
–> (-) feedback to hypothalamus to stop sending GnRH to anterior pituitary
–> Anterior pituitary stops sending Gonadotropins to testes
–> Testes stops making testosterone
Describe hypothalamic control of the ANTERIOR pituitary.
- Hypothalamus rel hormones that enter bloodstream
- -> Hormones reach anterior pituitary via blood
- -> Cause anterior pituitary to release its OWN hormones
- aka hypothalamic hormones = structural distinct from anterior pituitary hormones
Describe hypothalamic control of the POSTERIOR pituitary.
- Posterior pituitary rel hormones which are manufactured IN hypothalamus
- aka what we refer to as posterior pituitary hormones are actually prod in hypothalamus & move down axon to those hypothalamic neurons
- -> axon terminals of this neuron are located in posterior pituitary
- -> after hypothalamic hormones reach posterior pituitary, released into blood
Describe negative feedback regulation of the anterior pituitary, its targets, & its control mechanisms (5).
Gonadotropins (LH, FSH):
- TARGETS = ovaries & testes
- DIRECT control mech = hypothalamic hormone GnRH
- INDIRECT control mech = gonadal steroids which control gonadotropins via (-) feedback
ACTH:
- TARGET = adrenal cortex
- DIRECT control mech = hypothalamic hormone CRH
- INDIRECT control mech = adrenal steroids
TSH (thyroid stimulating hormone)
- TARGET = thyroid gland
- DIRECT control mech = hypothalamic hormone, thyroid releasing hormone (TRH)
- INDIRECT control mech = thyroid hormones
GH (Growth hormone)
- Control mech for GH incl. both releasing hormones & inhibiting hormones
- GnRH causes release of GH from anterior pituitary
- GHIH (growth hormone inhibiting hormone) inhibits rel of GH
Prolactin:
- TARGET = breast tissue
- DIRECT control mech = dopamine + PIH
- -> inhibits rel of prolactin
- -> prevents us from cont having ^prolactin thus ^lactation
- INDIRECT control mech = suckling stimulation
- -> ^prolactin secretion
- -> ^lactation
Discuss the relationship b/w gonadotropic releasing hormone (GnRH), gonadotropins, & gonadal hormones.
- Hypothalamus rel GnRH
- -> Stimulates anterior pituitary to rel gonadotropins (FSH, LH)
- -> Stimulates rel of gonadal hormones (ie. testosterone)
Define UNILATERAL CASTRATION
- Remove 1 of 2 testes
Discuss why unilateral castration do not prod sterility.
- Man prod less testosterone
- -> (-) feedback to hypothalamus
- -> hypothalamus prod ^GnRH
- -> ^gonadotropins & ^testosterone via compensation of remaining testes
- -> remaining testes prod 2x more testosterone than before
- -> ^sperm production
- -> No sig change/impairment in fertility
Define FERTILE
- Prod adequate sperm count
Define STERILE
- Prod inadequate level of sperm
Discuss difference b/w fertility & potency
- POTENCY = opposite of erectile dysfunction
- Fertility & sterility have nothing to do w/ sex behaviour
- -> only refers to sperm count
- Individual can be potent & yet sterile, or could have erectile dysfunction & still be fertile.
Define MENOPAUSE & describe its hormonal consequences.
- Ovaries stop prod estrogen & progestin
- -> (-) feedback
- -> ^GnRH & ^Gonadotropins
- -> but can’t prod estrogen
- -> decreased estrogen
- -> ^vaginal dryness
Describe the hormonal consequences of oral contraceptives.
- Some oral contraceptives contain synthetic estrogen & progestin
- -> Decreased GnRH & Gonadotropins
- -> Decreased natural estrogen & progesterone from ovaries
- -> Decreased ova release
What 2 hormones does the ADRENAL MEDULLA produce?
- Epinephrine & norepinephrine
- aka adrenaline & noradrenaline
Discuss the relationship b/w the adrenal medulla & emotions - discuss the 2 hypotheses.
Hypo #1:
- ^epinephrine + ^norepinephrine –> ^emo experience
Hypo #2:
- ^emo experience –> ^epinephrine + ^norepinephrine
> Both hypotheses are correct aka:
- Strong emotion experiences can ^catecholamine levels in blood AND ^catecholamines can ^emo experience
