physio UNIT 2 (endocrine)

cells with hormone receptors are

target cells

hormones can only cause action if

there is a target cell with the right receptor

steroid hormones

• bind to intra-membrane receptors

• modify genes and create new proteins,, takes awhile but effects are long term

• changes transcription of genes (increase or decrease of protein synthesis)

protein/amino hormones

• bind to receptor on cell membrane which triggers g protein activation

• activates pre existing proteins

posterior pituitary

• recieves hormones via axons in the hypothalamic hypophseal tract then capillaries

• acts on kidney (adh) , breast + human behaviour + uterine (oxytocin)

• cant make own hormones, stores them

oxytocin

peptide neurohormone that’s secreted by hypothalamus and stored in posterior pituitary

• cuddle + bonding

• promotes uterine contraction and milk ejection

adh (vasopressin)

30 day supply in posterior pituitary

• helps kidneys abosrb more water and pee less when body is dehydrated or has too much salt

lack of adh causes

frequent urination

Diabetes Insipidus

gland

stimulated to secrete hormones

ex. pituitary , adrenal

follicle

store hormones and release them when stimulated

ex. thyroid follicles

thyroid

• one of the largest endocrine glands

• butterfly shaped

• changes size when not functioning normally

• sitmulated by TSH (from anterior pituitary)

• makes T3 and T4

thyroid hormones are made in

the thyroid follicles

• ARE LIPOPHILLIC

• release is stimulated by tsh

8 functions of thyroid hormones

1. increases cardiac output and resting heart rate

2. increased circulation and vasodilation

3. increased hB and resp rate, more oxygen

4. bone remodelling

5. important for reproductive cycle

6. increased metabolism

7. clearance of medication and drugs

8. support alert and wakefullness

thyroglobin

cluster of tyrosine located in colloid

t4 is a

precursor of t3

all hormones made from adrenal cortex are

steroid hormones

5 major categories of hormones

1. androgen

2. estrogen

3. progestin

4. mineralocorticoids

5. glucocorticoid

there are ____ zones of adrenal cortex

3

zones of adrenal cortex

1. glomerulosa

2. fasciculata

3. reticularis

glomerulosa

top layer of adrenal cortex

• mineralocorticoids

• ex. aldosterone

fasciculata

second layer of adrenal cortex

• glucocorticoids

• regulate glucose metabolism

• ex. cortisol

reticularis

third layer of adrenal cortex

• androgen, estrogen, progestin

• ex. DHEA

adrenal medulla

NOT steroid hormone, acts on sympathetic ns

cortisol production and secretion is regulated through

hypothalamic-pituitary-adrenal axes

thyroglobin

protein that contains tyrosine, produced by follicular cells

• transported to colloid

neurotransmitters are always hydrophillic because

they must diffuse through cytoplasm

the peptide hormone-receptor complex causes change by

activating G-protein, affect intracellular enzymes, or alter function of ion channel

size and shape of the hormone is important

true

in order to be considered a hormone, it must be secreted by the endocrine glands

false. other organs can release hormones (the chemical must travel through blood)

pea sized gland

pituitary

purpose of pituitary gland

body fluid volume, metabolism, growth, stress adaptation, etc.

frequent urination of a symptom of

diabetes insipidis (lack of water absorption, dehydration from insufficient ADH)

ADH vs aldosterone

ADH is peptide hormone stored by post. pituitary. Increases water absorption in kidney and less urination. Decreases blood osmolarity since only water is exchanged, no ions.

Aldosterone is a steroid hormone secreted by zone glomerulus in adrenal cortex. Increases blood pressure by promoting Na absorption and K+ excretion. Water follows blood, so water/blood volume increases.

posterior pituitary hormones are stored in

axon terminal, released to bloodstream when needed

TRH is released by _____ to stimulate _______ and target _______

hypothalamus , TSH, targets thyroid gland to release T3/T4

CRH is released by _______ to stimulate _______ and target ________

hypothalamus to stimulate ACTH and target adrenal cortex (fasciculata) to release cortisol (and some aldosterone)

DHEA is released by ________

zone reticularis of adrenal cortex

epinephrine is released by _______ when stimulated by ______

sympathetic NS when stimulated by medulla cortex

dopamine inhibits

prolactin secretion

PRH stimulates ________ which targets _________

prolactin secretion and targets mammary glands to make milk

GnRH is released by ________ to stimulate secretion of _________ (A.P) which targets _________

hypothalamus, A.P. secretes LH, FSH to target gonads

GHRH is released by _______ to stimulate ________ which targets ________

hypothalamus to stimulate GH secretion to target liver and other tissues (makes energy for muscle and bones)

thyroxin

T4

T4 is more abundant, but less active so it’s condsidered a

precurser to t3

• t4 doesnt bind as strong to receptors

Thyroid hormone acts on almost every nucleated cell

true

• mostly by raising BMR

ACTH (anterior pituitrary) is activated by

CRH (hypothalamus)

CRH is released in response to

physical and emotional stress, (according to )circadian rhythem/wake cycle, low blood sugar

cortisol is a ______ and ______ hormone

sugar (glucocorticoid) and CATABOLIC hormone

cortisol promotes catabolism of

muscle (proteins) and adipose tissue (fatty acid)

cortisol promotes the liver to do

gluconeogenesis

cortisol has what effect on the immune system

supresses

cortisol is highest in the morning to help release _______

fuel for the day

• promote gluconeogenesis and hunger hormone

cortisol is mainly for regulating long-term

stress and sugar levels

blood glucose regulation by glucagon and insulin is _____ term

short term (hour by hour)

cushing’s syndrome is caused by

glucocorticoid medication causing excessive cortisol

cushing’s disease is caused by

pituitary tumour, releasing too much ACTH and excessive cortisol released

hyperglycemia

high blood sugar

symptoms of cushing disease/syndrome

• hyperglycemia

• weakened muscles

• osteoporosis (slowed growth in children)

• skin easily bruised and thin

• frequent infections

• fat redistributed to trunk and face

mineralocorticoid

secreted by glomerulus zone , regulate ions

main stimulus of aldosterone

RAAS/angiotension but also ACTH

effects of aldosterone

• increased Na+ absorption, K+ excretion

• increased blood volume (more water)

• increased blood pressure

• changes genes for Na/K pump

T3 and T4 are _____ hormones

hydrophobic amine

epinephrine is a ______ hormone

hydrophillic amine

catecholamines

water-soluble amine hormones/neurotransmitters derived from tyrosine

ex. epinephrine, dopamine (can be a neurohormone)

epinephrine binds on ____ receptors

extracellular

effects of epinephrine

• increased heart rate

• increased blood pressure

• vasodilation in muscle (need to fight)

• vasoconstriction in stomach and skin (conserve blood for important organs)

• increase gluconeogenesis (brain) + glycogen breakdown

• widened airways

onset and duration of epinephrine

quick-acting, short duration

epinephrine is best used for

fear/danger

cortisol is best used for

prolonged stress or fasting

cortisol onset and duration are

minutes to hours and long lasting

cortisol changes gene expression

true

islets of langerhans

endocrine cells in pancreas

secrete glucagon , insulin and somatostatin

beta cells

release insulin

alpha cells

release glucagon

delta cells

release somatostatin

pancreatic exocrine cells are _________ and make up ___% of pancreatic cells

acinar cells and duct tissue that release digestive enzymes , 98%

endocrine cells of pancreas make up _%

1-2 %

when blood sugar rises

beta cells release insulin

• stops lipolysis, glycogen breakdown

• signals muscle and adipose to take up glucose, store as glycogen in liver

• glucose leaves blood for storage or ATP (if needed)

glucose is only important for energy needs of

the brain

FA is mostly used by ______ for energy

muscles

when blood sugar drops

alpha cells release glucagon

• signals liver for glycogen breakdown and gluconeogenesis (new glucose)

• glucose released to blood

Type 1 diebetes

• appears in childhood

• due to destroyed beta cells by immune system (autoimmune)

• inherited or immune response

• treat with insulin

• 5-10% of cases

t3 and t4 are _______ hormones

hydrophobic amine

glycogen storage is stimulated by

insulin when blood glucose is high

glycogen breakdown and ______ are stimulated by

gluconeogenesis, glucagon (alpha cells)

type ____ diebetes is more common

2

type 1 diabetes is inherited and autoimmune

true

type 2 diebetes is _____ onset

gradual

• usually later in adulthood

type 1 diabetes is _____ onset

sudden

type 2 diebetes is caused by _________

target cells gaining insulin resistance from excessive sugar intake and lack of excersise. insulin is secreted initially but don’t respond well to receptors anymore , beta cells get tired and stop secreting

main risk factors of type 2

• lack of excersise

• diet

• family history

treatment for type 2

diet, excersise, oral drugs, insulin

main risk factors for type 1

inheritance, immune response

treatment for type 1

insulin

insulin, glucagon and serostatus are ____ hormones and their onset is

peptide, fast onset (works in minutes)

insulin is released as blood sugar rises after ____

eating

glucagon is released when blood sugar falls ______

between meals and after fasting

hormones secreted by neural triggers

neurohormones (TRH, CRH, GnRH, PRH, GHRH, dopamine)

hormones triggered by other hormones

TSH, ACTH, cortisol, t3/t4, testosterone/estrogen, aldosterone

hormones secreted by changes in body (humeral)

aldosterone, insuline, glucagon