Neuro Unit 2, lecture 6: Hormones

hormones

chemicals released by glands that travel through blood stream to act on target tissues

endocrine glands

release products INSIDE blood stream

exocrine glands

release products outside of bloodstream (sometimes outside of body) ie blood and sweat

peptide hormones

short string of amino acides (vasopressin (pair bonding)

amine hormones

modified version of a singular amino acid, aka monoamine hormones, ie epinephrine

steroid hormones

come from cholesterol, made from four rings of carbon atoms

where are hormones made?

PERIPHERAL SYSTEM: endocrine glands- adrenal and thyroid glands, gonads (testicles and ovaries) CENTRAL SYSTEM: neurohormones are produced by neuroendocrine cells (hypothalamus)

How do protein and amine hormones influence tissues?

protein and amine hormones bind onto specific receptors on the surface of a cell and activate chemical signals- second messengers- inside of the cell

how do steroid hormones impact the cells

steroid hormones cross the cell membrane and bind to receptors inside of the cell- steroid-receptor complex binds to specific regions of DNA and controls the expression of specific processes, slower than peptide/ amine hormones

pituitary gland

“master gland” releases important hormones and regulates other endocrine glands- two parts, anterior and posterior

pituitary stalk

connects the pituitary gland to the thalamuis

neuroendocrine cells

found in the pituitary, release hormones into the bloodstream

posterior pituitary gland

releases oxytocin and vasopressin into the bloodstream (social and parental behavior, mating/bonding) produce in neuroendocrine cells in the supraoptic and paraventricular nuclei of the hypothalamus, when AP in these cells reached terminal, neurohormones released right into thalamus

anterior pituitary

contains neuroendocrine cells that make and release TROPIC HORMONES: hormones that affect the release of other endocrine glands- hypotha;klamus regs the release of tropic hormones from the anterior pituitary using RELEASING HORMONES- axons of neuroendocrine cells that produce these hormones meet at MEDIAN EMINENCE-

tropic hormones

hormones that affect the release of other endocrine glands

Median eminence

contains blood vessels that form the HYPOTHALAMIC PITUITARY PORTAL SYSTEM- hypothalamic neurons make releasing hormones, which travel to the anterior pituitary, triggering the release of tropic hormones into circulation

how is cortisol released into the body

In response to stress or waking up rhythm, hypothalamus synthesizes and releases CRH (corticotropin releasing hormone) into the pituitary gland, which signals it to release the tropic hormone ACTH (adrenocorticotropic hormone) which travels through the bloodstream to the adrenal glands on top of the kidneys which release cortisol

how are sex hormones released in the body

the hypothalamus produces the releasing hormone GnRH (gonadotropin releasing hormone) which travels to the anterior pituitary triggering the release of the tropic hormones LH and FSH which travel to the gonads (testes+ovaries) and trigger the release of sex hormones testosterone and progesterone

differences between male and female brains

male brain is 8-10% heavier, sexually dimorphic nucleus of the preoptic area (SNDPOA)=2.5x larger in males, 2.2x more cells, interstitial nucleus of the hypothalamus (INAH) 2 and 3 cell groups have larger volume in men compared to women

role of hormones in sex diferentiation

genes effect gonad development- XY have SRY (sex determining region y for production of testosterone) X X do not, gonadal hormones initiate sexual diff of brain (masc or non masc brain) environmental factors can impact gene and hormone expression

Who are transgender male to female womens’ brains most similar to?

BIOLOGICAL WOMEN- environmental factors in pregnant women can alter the expression of SRY, leaving brain structure of MTF women most biologically similar to ppl AFAB