Flashcards in Vertebrates 20 - Endocrine Deck (21)
5 ways of chemical signaling
Autocrine, paracrine, endocrine, neruoendocrine, exocrine
Go through bloodstream to travel to target
Stimulated and release hormones into blood. Neurons from hypothalamus
Especially pheromones, sensed by another organism
Peptides and proteins
Small. Insulin, ADH. Bind to membrane receptors.
From amino acids, epinephrine and thyroxine. Bind to membrane receptors
From cholesterol. Testosterone, estrogen, cortisol. Hydrophobic so they have carrier proteins and then diffuse through membrane
Ant. and Post. Controlled by the hypothalamus
Homeostatic mechanisms: hunger, thirst, temp. Responds to brain inputs (stress, circadian rhythms, etc).
Adenohypophysis. Releases TSH, FSH, LH, GH, Prolactin (milk and some brain), ACTH, MSH. Connected by a portal system to hypothalamus which sends hormone messages.
Neurohypophysis. Nerves from hypothalamus enter and release hormones from there. ADH and oxytocin.
Hypothalamus, less obvious pituitary. No distinct adrenal or thyroid glands.
More developed pituitary. Adrenal in separate places, cortex (suprarenal - cortisol) and medulla (interrenal - adrenalin).
Pituitary lacks portal system but has nerve connection to hypothalamus. Adrenal glands together but in multiple places.
Portal system present. thyroxine stimulates metamorphosis
One pair of adrenal glands
Prolactin stimulates crop milk (secretion to feed young in some birds). 10x Glucagon, more thyroxine for higher metabolism
Catabolic and anabolic pathways
Catabolic breaks down, so lower body weight (cortisol, thyroxine); anabolic builds (testoterone)
Know the thyroid, cortisol and testosterone axes
Hypo - TRH - Ant Pit - TSH - Thyroid - Thyroxine - shut off the others, increase metabolism. … ACTH - Adrenal - Cortisol - shut these off; Hypothalamus - GnRH - Ant Pit - LH - Testes - Testosterone - build muscle etc, turn off the other
Effects of hormones (general)
Cell response and also trophic effects (growth of cells)