Lecture 5 (endocrine system) Flashcards
Hormones
chemical messengers that travel through the blood stream
types of hormones (three types:)
1.) Peptide Hormones = chains of amino acids (ex. endorphins)
2.) Amine Hormones = small molecules derived from a single amino acid (ex. seretonin)
3.) Steroid Hormones = lipid soluble hormones derived from cholesterol (ex. testosterone)
chains of amino acids (ex. endorphins)
peptide hormones
small molecules derived from a single amino acid (ex. seretonin)
amine hormones
lipid soluble hormones derived from cholesterol (ex. testosterone)
steroid hormones
Hormone receptors (two types:)
1.) Metabotropic receptors (GCPR’s)
*peptide and amine hormones
2.) Intracelluar nuclear receptors
*steroid hormones
*bind to receptor, active transport/pass through lipid membrane to the cell nucleus
Intracelluar nuclear receptors
used by steroid hormones
they bind to receptor, pass through due to being lipid soluble (via transporters) go to nucleus
what regulates hormones?
Negative feedback = brain monsters internal and external cues
*output of horses feedbacks to inhibit more output
Neuroendocrine cells
receive synaptic input and fire action potentials = when they do hormones are released into the bloodstream
posterior pituitary gland releases:
releases:
1.) oxytocin = promotes partition (mother infant bond, tribal bonds ect.)
2.) Vasopressin = regulates fluid balance (water/thirst regulation)
where are oxytocin and vasspressin made?
the supraoptic and paraventricular nuclei (hypothalamic regions)
what hormone does the anterior pituitary gland make?
tropic hormones = act on glands (such as gonads)
how does the anterior pituitary gland release hormones?
1.) neuroendocrine cells synthesize releasing hormones
2.) release hormones travel along the hypothalamic-pituitary portal system —– govern the release of hormone
3.) releasing hormone travels to anterior pituitary via portal veins
4.) cells in the anterior pituitary respond via releasing tropic hormone into the bloodstream
where are neuroendocrine cells ( which are responsible for secreting hormone into the bloodstream)
In the hypothalamic-pituitary portal system
type of releasing hormone (stimulates FSH and/or LH):
Gonadotropin-releasing hormone (GnRH)
* stimulate follicle-stimulating hormone (FRH)
and / or
* stimulate luteinizing hormone (LH)
In females = growth and maturation of eggs / secretion of estrogen from follicles
in males = sperm production
follicle - stimulating hormone (FSH)
made by neuroendocrine cels (a releasing hormone)
In females = stimulates follicles to rupture releasing eggs. which form the corpus luteum —which secretes progesterone
in males = produces testosterone
luteinizing-hormone (LH)
Leydig cells
made by neuroendocrine cells (a releasing hormone)
Luteinizing-hormone (LH)
In females = stimulates follicles to rupture releasing eggs. which form the corpus luteum —which secretes progesterone
in males = produces testosterone
follicle - stimulating hormone (FSH)
In females = growth and maturation of eggs / secretion of estrogen from follicles
in males = sperm production
Leydig cells
produce and secrete testosterone via LH
what do the ovaries produce (two things):
eggs (ova)
sex steroids
Two main types of sex steroids (females)
progestins = “to bear” helps maintain pregnancy
main steroid is progesterone
Estrogen = “frenzy” periodic cycle, receptivity
**main steroid is estradiol”
Ovulatory cycle (4 main steps:)
1.) Follicle-stimulating hormone stimulates follicles to grow secreting estrogen
2.) estrogen stimulates hypothalamus and pituitary to release luteinizing hormone which triggers the follicles to rupture releasing eggs. develop into corpus luteum.
3.) corpus luteum secretes progesterone which helps maintain uterus for pregnancy
4.) in no pregnancy then cycle begins again….
organizational/
activation hypothesis
differential exposure to hormones (in early development) influence the neural organization/circuit and underlying sexual behaviour
organizational effects
permanent changes that occur in the brain
activating effects
transient changes that occur to the brain
