17 Endocrine

hypothalamus

this gland produces ADH, oxytocin, & releasing and inhibiting hormones

• located in third ventricle

antidiuretic hormone (ADH)

Hormone conserves water by targeting distal tubules of nephrons

• slows urine formation

• hyposecretion: diabetes insipidus

diabetes insipidus

Due to hyposecretion of ADH resulting in polyuria & polydipsia due to body’s inability to regulate fluid balance

Oxytocin (pitocin)

delivery of baby by stimulating smooth muscle contraction of uterus

• works in conjunction w/t prolactin, stimulate contraction within breast

• Males: movement of sperm through reproductive tract

Posterior pituitary

Stores oxytocin & ADH

• called neurohypophysis (composed of neurons)

growth hormone (GH), prolactin (PRO), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle stimulating hormone (FSH), luteinizing hormone (LH), interstitial cell stimulating hormone (ICSH)

What hormones does the anterior pituitary gland produce? (7)

anterior pituitary

Also called the adenohypophysis (gland below thalamus)

• produces: growth hormone, prolactin, thyroid stimulating hormone, adrenocorticotropic hormone, follicle stimulating hormone, luteinizing hormone, interstitial cell stimulating hormone

sella turcica, sphenoid

the pituitary gland sits in the ____ ____ which is located in the _______ bone

tropic hormones

hormones that target another endocrine gland to secrete hormones

mineralocorticoid

hormones from the adrenal cortex that regulate composition & concentration of electrolytes (ions) in body fluids

• Ex: aldosterone

glucocorticoid

group of hormones released from the adrenal cortex, helps regulate glucose levels

• includes cortisol & corticosterone

growth hormone (GH)

Hormone produced by anterior pituitary responsible for growth & protein synthesis

• Targets: general + epiphyseal discs

• hyposecretion: dwarfism & Simmond’s disease

• hypersecretion: giantism & acromegaly

prolactin (PRO)

Produced by anterior pituitary responsible for formation of milk

• targets mammary glands

thyroid stimulating hormone (TSH)

Hormone produced by anterior pituitary for thyroid stimulation

• targets thyroid gland

adrenocorticotropic hormone (ACTH)

hormone produced by anterior pituitary that stimulates adrenal cortex

• targets adrenal cortex

follicle stimulating hormone (FSH)

hormone produced by anterior pituitary responsible for oogenesis & estrogen production in females or spermatogenesis in males

• stimulates maturation of follicle & oocyte

• targets ovarian follicles or seminiferous tubules

• hyposecretion: infertility

Luteinizing hormone (LH)

hormone produced by anterior pituitary responsible for ovulation, formation of corpus luteum, & secretion of progesterone

• peaks at day 14 causing ovulation

interstitial cell stimulating hormone (ICSH)

hormone produced by anterior pituitary that promotes testosterone production

• targets interstitial cells of testes

thyroid

gland also known as “shield” in Latin, produces T3, T4, & calcitonin

follicular cells, thyroglobulin

_____ _____ of the thyroid is responsible for the production of T3 & T4

• _____ is the pink colloid and precursor of T3/T4

parafollicular cells

thyroid cells that are responsible for secreting calcitonin

triiodothyronine & thyroxin (T3, T4)

Hormones produced by the thyroid that are responsible for metabolism & development

• Target: general

• w/o it, neural connections can’t be made

• newborns tested for this, given synthroid

• hyposecretion: cretinism & myxedema

• hypersecretion: grave’s disease

calcitonin

Hormone produced by thyroid gland responsible for Ca deposition, stimulates osteoblast to pull calcium into bones

• target: bone

parathyroids

posterior of thyroid usually 4 nodules, releases PTH

parathyroid hormone (PTH)

Hormone that raises blood Ca

• withdraws Ca from bone via osteoclasts

• Targets: bone, kidney, intestine

• hyposecretion: tetany

• hypersecretion: osteitis, fibrosa, cystica

adrenal medulla

Highly vascularized portion of the adrenal gland, core of gland

• release catecholamines epinephrine (adrenaline) & norepinephrine

epinephrine (adrenalin)

Hormone secreted by adrenal medulla, same function as sympathetic nervous system (flight/fight)

• target: general

• hypersecretion: hypertension

urinary, reproductive, digestive

Epinephrine inhibits what 3 systems?

adrenal cortex

outer portion of adrenal gland responsible for secreting cortisol, cortisone, aldosterone, and sex hormones (androgens)

Cortisol, cortisone

Hormones released by the adrenal cortex functions in stress and anti-inflammatory responses; considered glucocorticoids

• target: general

• hyposecretion: Addison’s disease

• hypersecretion: Cushing’s disease

aldosterone

a mineralocorticoid, conserves NaCl and water

• targets kidney tubules

• hyposecretion: Addison’s

• hypersecretion: cushing’s

70-100 mg/dL

At what concentrations is blood glucose maintained at?

estrogen, androgen

Sex hormones produced by the adrenal cortex

• hypersecretion of one of these hormones in females may lead to varying degrees of precocity & virilism; while this is a secondary site of production in males it is the primary site for females

pancreatic islets

Also known as islet of Langerhans, produces insulin and glucagon

ascinus

cells in the pancreas, surrounding islet of Langerhans that secrete digestive enzymes

insulin

hormone produced by beta cells of pancreatic islets, function in sugar transport, storage, & usage

• target: general

• hyposecretion: diabetes mellitus

glucagon

produced by alpha cells of pancreatic islets, function is to raise blood sugar

• target: general

testes

gonads, responsible for production of testosterone

• #13

testosterone

hormone produced primarily in the testes, promotes maleness

• target: general

• hyposecretion: infertility

ovaries

gonads that produce estrogen & progesterone

estrogen

hormone produced in the ovaries that promote femaleness + secondary sex characteristics

• target: general

• hyposecretion: infertility

• lack of linked to osteoporosis

progesterone

hormone produced by the ovaries that maintain pregnancy; levels increase after ovulation

• target: uterus

• hyposecretion: infertility

thymus

gland is located in the chest, creates thymosin

thymosin

hormone secreted by the thymus responsible for immunity

• target: lymphoid tissue

• hyposecretion: immune failure

hormon

Derived from Greek, meaning to excite

• hormones can also be inhibitory

pineal

Gland that secretes melatonin

melatonin

hormone produced by the pineal gland causes drowsiness & inhibit early sex development

• targets: sex organs

hormonal, humoral, nervous

What are the 3 forms of endocrine stimulation (mode of secretion)?

hormonal stimulation

stimulation, the release of another hormone triggers release of the hormone

• Ex: thyroid stimulating hormone from anterior pituitary triggers thyroid hormone in the thyroid

humoral stimulation

changes in level of nutrient or ion in the blood triggers release of the hormone

• Ex: insulin, glucagon, ADH

nervous system stimulation

stimulation by the nervous system triggers release of the hormone

• Ex: epinephrine & norepinephrine

direct gene activation

steroid (fat soluble) hormones enter target cells & bind to intracellular receptors & can influence gene expression

liver, kidney

Hormones are quickly broken down in the ____ & ____

Permeability, protein synthesis, enzyme activation/ suppression, secretion, mitosis

Typically effects (mechanisms) of hormones include: (5)

reproduction, development, stress, fluid/ electrolyte balance, metabolism

Significant things controlled by hormones include: (5)

goiter

caused by iodine deficiency, abnormal growth of the thyroid gland (capture more iodine)

• non toxic vs toxic (cancerous)

amino acid/ protein and steroids

What are the 2 general chemical groups of hormones?

• some are simply altered (adrenalin & thyroxin), short (ADH), or long (insulin) chains

• complex rings made from cholesterol, includes all sex hormones + products of adrenal cortex

Hormone receptor complex

In a lipid soluble hormone a _____ _____ _____ is formed when the unbound hormone binds with intracellular receptors

Hormone response element

For lipid soluble hormones, once the HRC binds with a DNA sequence called _______ _______ ______ it stimulates mRNA synthesis resulting in a new protein

signal transduction pathway

biochemical events initiated when water soluble hormone binds to plasma membrane receptor

• the hormone is considered the first messenger

second messenger

an intracellular chemical that modifies activity within a cell after a first messenger binds to plasma membrane

• Ex: cAMP, DAG, Ca2+

adenylate cyclase & phospholipase C

What are the 2 most common signal transduction pathways?

G protein

specific protein that when activated by membrane receptor, relays signal to another membrane protein & alters the activity of that protein

• Both signal transduction pathways go through this

cAMP

When adenylate cyclase & G protein binds together, increases the formation of ______ which activates protein kinase

protein kinase

an enzyme that adds phosphates to other molecules (phosphorylation), results in activation or inhibition

PIP2

Binding of G protein & phospholipase C results in splitting of _____

• splitting of ____ results in two secondary messengers DAG & IP3

DAG

second messenger that remains in the membrane, similar action to cAMP where it activates protein kinase which phosphorylates other molecules

IP3

second messenger that diffuses into cytosol, causes an incr in intracellular Ca2+ [] which acts as a third messenger

Diabetes mellitus

An endocrine disorder that affects 5% of those in the US, 3rd cause of death

• Starving in the land of plenty

• syndrome: glucosuria, hyperglycemia, polyphagia, ketoacidosis

• complications: retinopathy, nephropathy, atherosclerotic coronary & peripheral arterial disease, peripheral & autonomic neuropathies

Type 1 diabetes (IDDM)

most serious of the diabetes mellitus with juvenile onset

• 5-10% of total

• prone to ketosis, microangiopathy, gangrene, blindness, impotence

• could be autoimmune

• insulin injections vital

ketosis

Occurs when fats & proteins are burned anaerobically producing ketones, making the blood acidic > denaturing of proteins

• cholesterol of cell membrane taken out, resulting in rigid membrane

type 2 diabetes (NIDDM)

Onset typically more mature, causes can be genetic or obesity

• 80% are obese

• atherosclerosis: saturated fats no good but unsaturated fats good

• treatment: diet, exercise, oral hypoglycemics

gestational diabetes (GDM)

may occur during pregnancy, “warning shot”

• 80% become NIDDM within 20 years unless they get their fat% in check

• breast feeding helps shed some fat

• aerobic exercise

general adaptation syndrome (GAS)

Responses that occurs in stress reactions, same responses despite different stressors

• tachycardia, hyperventilation, sweating, hyperglycemia, hypertension, high adrenalin + cortisol

• stressors typically extremes

alarm and resistance reaction

What are the two types of response mechanisms to stress monitored by the hypothalamus?

alarm reaction

reaction in response to stress, involves sympathetic nervous system & adrenal medulla

• SNS speeds things up

• Adrenalin prolongs SNS responses

• lasts seconds to minutes

resistance reaction

Slower & more prolonged stress response involving cortisol & aldosterone

• body is supported for increased activity over a period of time

• response & hormones can suppress pain

exhaustion stage

Occurs following prolong stress & body can’t continue to work in high stress capacity

• cortisol levels may be depleted

• hypokalemia (low potassium) may lead to cell death

• organ fatigue & failure

  • aldosterone gets rid of further potassium

health, age, sex, nationality, past experiences

What factors influence stress reaction? (5)