BIOL 2150 ECU Dr. Jones EXAM 1

what is the length of time it takes for hormones to decrease in blood? what hormones have the shortest?

half life; lipid insoluble

the _____________ _____________________ releases chemical messengers (hormones) into the blood

endocrine system

long distance chemical signals that control the metabolic activities of cells

hormones

organ response is often ______________ but ________________-

delayed but prolonged

the endocrine system consists of a ____________________ _____________, _____________ and _______________ dispersed throughout the body

neuroendocrine system, glands and tissue

name some features of the endocrine system

ductless, release hormones into surrounding tissue fluid and highly vascularized

goblet cells release

mucus

the neuroendocrine organ is the

hypothalamus

name the endocrine glands

pituitary, thyroid, parathyroid, adrenal, pineal

what are some other organs containing endocrine tissue?

pancreas, ovaries/testes and placenta

endocrine cells are also found scattered throughout the body, they are found where?

adipose cells, thymus, small intestine, stomach, kidneys, heart

what are some functions of hormones?

regulate the activity of cells, change plasma membrane permeability, stimulate protein synthesis, activate/deactivate enzymes, induce secretion of molecules from cells, stimulate mitosis

hormones that cannot get through the plasma membrane receptors and bind to transmembrane protein receptors in the phospholipid membrane

amino acid based hormones

hormones that diffuse easily across the plasma membrane and bind to an intracellular receptor complex

steroid based hormones (and thyroid hormones)

what are the three types of stimuli that cause release of hormones?

humoral, neural, hormonal

type of stimuli in which hormones are released in response to levels of molecules or ions in the blood

stimulus: low conc. of Ca+ in the blood

response: parathyroid gland release PTH which increases Ca+

humoral stimulus

type of stimuli where nerve activity stimulates hormone release

stimulus: action potentials in the preganglionic sympathetic fibers to adrenal medulla

response: adrenal medulla releases epinephrine and norepinephrine

neural stimuli

type of stimuli where a hormone from one gland causes a hormone to be released from another

stimulus: hormones from hypothalamus

response: anterior pituitary gland secretes hormones that stimulate other endocrine gland to secrete hormones

hormonal stimuli

hormones circulate the entire body through the vascular system but only affect certain tissue cells, these are called

target cells

the response of target cells depends on several factors:

blood levels of the hormone (amount of hormone)

# of receptors on target cells

affinity of binding between hormone and receptor

receptors are dynamic and can change in both ______________ and ________________

number and affinity

number of receptors is increased, happens when hormone levels are low and cell is trying to produce a response to the hormone

up regulation (exocytosis)

number of receptors is decreased, happens when hormone levels are high and cell is trying to reduce its response to the hormone

down regulation (endocytosis)

when receptors are in a _______________ _______________ state, the receptor has a strong attraction for the hormone and do not need much hormone for activation

high affinity

when receptors are in a _______________ _______________ state, the receptor has a weak attraction for the hormone and need much hormone for activation

low affinity

distant regulation

endocrine

self regulating

autocrine

local regulation

paracrine

if a hormone is _________ _________________ (all other hormones) it is transported freely in the blood; their target organ effect is usually rapid

lipid insoluble

why does free floating hormone by itself in blood not last long and only target effect is rapid?

because it cannot last long in blood when not attached to anything

if a hormone is ________________ _____________ it is transported in blood attached to a plasma protein; their target organ effect takes hours or days

lipid soluble

for a full target cell response there must be more than one hormone present

permissivness

when more than one hormone produces the same effects but together their effect is much larger

synergism

when one hormone opposes the action of another

antagonism

secretes 6 major hormones, connected to the hypothalamus by the infundibulum and has two major lobes; the anterior and posterior

the pituitary gland

is neural tissue; not a true endocrine gland

the posterior pituitary

a hormone storage area, releases neurohormone made in the hypothalamus, does NOT itself make hormone

posterior pituitary

supraoptic and paraventricular nuclei of the hypothalamus send ADH and pxytocin to the posterior pituitary via the ________________ __________________ tract

hypothalamic hypophyseal tract

posterior lobe of the pituitary gland + infundibulum =

neurohypophysis (neural part of the pituitary gland)

made in the paraventricular nucleus and is release in high amounts during child birth and in nursing mothers, result of positive feedback mechanism

oxytocin

controls blood volume directly related to blood pressure, made in the supraoptic nucleus, prevents urine formation and prevents dehydration

ADH (antidiuretic hormone)

what in the hypothalamus monitor the blood?

osmoreceptors

how does ADH work in the body?

osmoreceptors send impulses to the supraoptic nucleus, ADH is made and released, goes to the kidney tubules and causes water to be reabsorbed and less urine is produced

ADH is also called _______________ because it causes vasoconstriction when released in large amounts if BP drops severely low

vasopressin

how is alcohol a diuretic?

it inhibits ADH secretion causing an increase in urine output

ADH deficiency or ________ ___________________ causes large urine output and intense thirst

diabetes insipidus

diabetes = ____________ insipidus = ___________________ mellitus= _____________________

siphon, without taste, sweet taste

glandular, no neural (without neurons) connection to the hypothalamus, is a vascular connection

anterior pituitary gland

the anterior pituitary is also called the ________________ _________________ system: primary capillary plexus, hypophyseal portal veins and secondary capillary plexus

hypophyseal portal system

in the anterior pituitary, hormones from the hypothalamus control the release of hormones from the

adenohypophysis

a portal system is two ______ _______________________ (beds) connected by veins

capillary plexuses

the anterior lobe of the pituitary have ____ major hormones, all of which are proteins (steroid based hormones); four are ________________ (TSH, ACTH, FSH, LH) and regulate secretory action of other endocrine glands which then produce the final hormones

two are _______________ (growth hormone and prolactin) they are the final hormones

6 hormones, trophic, not trophic

what are the trophic hormones? what do trophic hormones do?

TSH, ACTH, FSH and LH; regulate secretory action of other endocrine glands

what are the "final hormones" that are not trophic?

growth hormone and prolactin

the major target of growth hormone is?

bone and skeletal muscle

growth hormone is an _______________ or building hormone

anabolic

secretion of growth hormone is regulated by what?

GHRH (growth hormones releasing hormones) and GHIH (growth hormones inhibiting hormones)

________ stimulates growth hormone release and ____________ inhibit growth hormone release

GHRH and GHIH

the hypothalamus stimulates the _____________ __________________ to release growth hormone

anterior pituitary

what actions does growth hormone have on metabolism?

takes fats and uses as fuel, conserves blood glucose levels by decreasing glucose uptake and use

growth hormone stimulates the liver, skeletal muscles and bone to produce what?

insulin-like growth factors

what do insulin-like growth factors stimulate?

skeletal muscle and bone growth

caused by excess growth hormone in children

gigantism

caused by excess growth hormone in adults, causing coarse, flaccid features and thickening of soft tissue

acromegaly

insufficient growth hormone in children, proportionate

pituitary dwarfism

caused by insufficient growth hormone in adults (very rare), leads to slightly accelerated aging

acquired or genetic growth hormone deficiency

a trophic hormone which stimulates the development and activity of the thyroid gland

TSH

release of TSH from the anterior pituitary gland is triggered by what?

TRH (thyrotrophin-releasing hormone) from the hypothalamus

what inhibits TSH secretion?

thyroid hormone and Somatostatin

a hormone that stimulates the adrenal cortex to release corticosteroid hormones, e.g. glucocorticoids

ACTH (adrenocorticotrophic hormone)

release of ACTH is stimulated by what?

corticotrophin releasing hormone from the hypothalamus

the gonadotropins are

FSH and luteinizing hormone

hormones that are absent prior to puberty

FSH and LH

release of FSH is stimulated by

gonadotropin releasing hormone

a final hormone which stimulates milk production in females and may enhance testosterone production in males

prolactin

low levels of estrogen lead to increased ________________

prolactin inhibiting hormone

high levels of estrogen lead to increased __________________

prolactin releasing hormone

the largest pure endocrine gland in the body, heavily vascularized and composed of hollow spherical follicles

the thyroid gland

follicular cells of the thyroid gland produce a glycoprotein called what?

thyroglobulin

how is iodine in the thyroid trapped into follicular cells?

by active transport

Iodine + tyrosine =?

MIT (monoiodotyrosine)

Iodine x2 +tyrosine= ?

DIT (diiodotyrosine)

DIT + DIT=?

T4 (thyroxine)

DIT +MIT= ?

T3

iodinated tyrosine from thyroglobulin makes

thyroid hormone

the thyroid gland is unique in that it is able to what?

store hormone extracellularly

what cells produce calcitonin?

parafollicular cells

is the body's major metabolic hormone, consists of T4 and T3

thyroid hormone

name some functions of thyroid hormone

-increases the body's use of glucose

-increases metabolic rate of cells

-increases heat production

-maintains blood pressure

-regulates tissue growth and development

-maturation of reproductive organs

-very important for skeletal and nervous system development

how does T3 affect target tissue receptors?

by entering the cell and bind to intranuclear receptors which results in an increase in DNA transcription

hypothyroidism in adults is also called

Myxedema

what causes hypothyroidism (myxedema)?

defective thyroid, TSH or TRH too low and inadequate dietary iodine

what are some symptoms of hypothyroidism?

cold, constipation, dry skin, edema, lethargy and mental sluggishness

caused by low iodine, also when colloid is produced but no iodine is available to make thyroid hormone and the pituitary secretes increasing amounts of TSH (which is useless)

goiter

what is the number one cause of hypothyroidism?

Hashimoto's disease

also known as chronic lymphocytic thyroiditis, the immune system attacks the thyroid gland resulting in inflammation causing hypothyroidism; primarily affects middle aged women

Hashimoto's

in children, hypothyroidism is called

neonatal hypothyroidism

caused from a missing or abnormally developed thyroid gland, the pituitary gland fails to stimulate the thyroid and results in defective thyroid hormone production

symptoms: short/disproportionate body, irreversible effects on mental development, puffy face and not reversible

cretinism

What is the most common cause of hyperthyroidism? what are some other causes?

Grave's disease; inflammation of they thyroid (viral) or noncancerous tumors

when abnormal antibodies mimic TSH so blood thyroid hormone levels are high

hyperthyroidism