IB Bio Endocrine System

endocrine system

body system made up of glands & hormones they produce

all hormones are ligands but…

not all ligands are hormones

glands

maintain homeostasis (constant environment) & regulate development

hormones

transported throughout body by blood

blood acts as a…

highway

what amount of hormone is needed to have significant influence on target tissues?

minute amounts of hormone

target tissues

tissues where its cells have receptors that bond to hormone

hormones can be what?

* steroids
* peptides
* modified amino acids

non-endocrine glands

make other substances besides hormones

example of non-endocrine glands

sweat glands

how do hormones cause coupled reaction?

1. hormone bonds to receptor on membrane of cells in target tissue
2. inactive messengers become active messengers

what happens to effect of hormone in coupled reaction?

effect of hormone = amplified

why is pituitary gland called “master gland”?

b/c acts as target tissue of some hormones released by other glands

pituitary gland consists of?

* anterior (front) pituitary gland
* posterior (back) pituitary gland

hypothalamus relationship w/ pituitary gland

hypothalamus sends signals that tells pituitary to secrete certain hormones

hormones in posterior pituitary gland

* ADH (antidiuretic hormone)


* oxytocin

what makes ADH & oxytocin?

neurosecretory cells of hypothalamus

ADH function

* increases reabsorption of H2O in kidneys (takes H2O out of blood to store in kidneys)
* determines whether kidneys absorb or release H2O into blood? (\*\*clarify)

oxytocin function

stimulates release of milk from mammary glands

how does the nervous system and endocrine system differ? 

* nervous: made up of neurons, faster
* endocrine: made up of glands & hormones they produce, slower, causes developmental changes.

posterior pituitary gland function

controls body parts, not other glands

anterior pituitary gland function

regulates hormone production of other endocrine glands

what is anterior pituitary gland affected by?

affected by releasing hormones made by neurosecretory cells of hypothalamus

what do releasing hormones in the anterior pituitary gland stimulate?

stimulate release of tropic hormones

tropic hormones

hormones whose target cells are other endocrine glands

hormones in anterior pituitary gland

* TSH (thyroid stimulating hormone)
* ACTH (adrenocorticotropic hormone)
* FSH (follicle stimulating hormone)
* LH (luteinizing hormone)
* PRL (prolactin)
* GH (growth hormone)

non tropic hormones

hormones whose target cells do not make up other endocrine glands

two non tropic hormones

PRL & GH

TSH function

affects thyroid by secreting T3 & T4

ACTH function

affects adrenal cortex by secreting glucocorticoids

FSH function

affects ovaries by regulating oogenesis

LH function

affects testes by regulating spermatogenesis

oogenesis

meiosis that produces eggs

spermatogenesis

meiosis that produces sperm

PRL function

helps mammary glands regulate milk production

GH function

stimulates muscle & bone cell growth

how does pancreas produce antagonistic hormones?

by having bundles of glucocorticoids w/ alpha & beta cells

how does liver store sugar?

by converting glucose → glycogen for storage

alpha cells

* produce glucagon
* increases blood glucose level in liver
* glycogen in liver → released into blood as glucose

beta cells

* produce insulin
* decreases blood glucose level in liver, muscle & fat cells
* glucose leaves blood → stored in liver as glycogen

pancreas (diagram)

blood---------liver

glucose → glycogen (using insulin/beta cells)

glucose

adrenal gland parts

medulla & cortex

hormone in medulla

epinephrine (adrenalin)

epinephrine function

* affects blood vessels, liver, & heart
* causes increase in blood glucose, blood vessel constriction, & fight or flight response

hormones in cortex

* glucocorticoids (ex: cortisol)
* mineralocorticoids (aldosterone)

glucocorticoids function

* affect entire body
* help increase blood glucose
* greater in long-term stress

mineralocorticoids function

* affect kidney
* increases rate of reabsorption of Na+ & K+

hormones in thyroid

* T4 (thyroxin)
* T3 (triiodothyronine calcitonin)
* calcitonin

T4 & T3 function

causes body to increase cellular metabolism

cellular metabolism

sum total of all chem reactions in organism

calcitonin function

causes bones to absorb Ca2+ from blood

where is parathyroid?

within thyroid

hormone in parathyroid

PTH (parathyroid hormone)

PTH function

causes bones to release Ca2+ into blood

PTH works antagonistic to…

to calcitonin

as women grow older…

calcium in body decreases b/c calcitonin decreases or PTH increases

hormone in testes

testosterone

testosterone function

* affects testes & to lesser extent, rest of body
* affects spermatogenesis & secondary sexual characteristics

hormone in ovaries

* estrogen
* progesteron

estrogen function

* affects uterus & to lesser extent, rest of body
* affects menstrual cycle & secondary sexual characteristics

progesterone function

* affects uterus & to less extent, rest of body
* affects menstrual cycles & pregnancy

pineal gland location

in brain

hormone in pineal gland

melatonin

melatonin function

* affects entire body
* helps regulate circadian rhythms
* disrupted during spring forward

how does adipose tissue store glucose?

excess glucose gets stored in the liver as glycogen or, w/ help of insulin, converted into fatty acids, circulated to other parts of the body, & stored as fat in adipose tissue

what is fight or flight response?

automatic physiological reaction to an event perceived as stressful or frightening & is triggered by release of hormones