BIOL 121 Lecture Notes - Lecture 26: Adrenal Medulla, Posterior Pituitary, Anterior Pituitary
Biol 121
Intro to Physiology
Summer 2018
● Control of secretion:
○ Plasma levels of nutrients/ ions
■ Parathyroid
■ Insulin
■ glucagon
○ Nervous system
■ close connections in posterior pituitary and adrenal medulla, sympathetic
controls adrenal medulla, anterior pituitary is controlled by the
hypothalamus, thyroid, adrenal cortex (cortisol), gonads
○ Other hormones (tropic hormones)
● Secretion- glands do this, specific action of kidneys
○ Endocrine
■ secrete hormone
○ Exocrine
■ not hormone excretion
○ Excretion
■ process of removing something from our bodies, like a waste material or
something, kidneys, liver, ungs (excrete co2) skin, GI tract
○ Absorption
■ from Gi tract into the tissues, minor absorption through skin and mucous
membranes
● Reabsorption- specialized function of the kidney
○ Kidney function: blood goes through the filtration system unto a filtrate, cells and
proteins stay in the blood, water and other small substances go into the filtrate
which is excreted as urine, can have reabsorption and secretion.
○ Take something from the filtrate and reabsorb it back into the blood, secretion
would increase the concentration of something in the urine and reabsorption
would decrease it
● Resorption
○ break down of a tissue, primarily bone
● Endocrine system can secrete a hormone activate in blood by metabolism also inactivates
by metabolism, excreted in urine, target cells bind to receptor and produce a cellular
response,
● Water/lipo soluble is relative
● Sewage system has a lot of estrogen from women’s birth control when they urinate.
Human estrogen affect wildlife
● Permissiveness-when 2 hormones are present fatty acid is released, but if epinephrine and
thyroid secrete fatty acid it is not just a 1 + 1 effect, it is much higher
○ One hormone is manipulating something on activation sites and response is
greater than expected
○ Pharmacological effects on hormones- ???? administration of large quantities of
hormones give different effect than naturally released hormones
