BIOL2151 Jones Exam 1 Review

hormones

long distance chemical signals that control metabolic activities of cells

delayed; prolonged

in the case of hormones, organ response is usually _____________ but _____________

neuroendocrine organ, glands, tissue

the endocrine system consists of:

ductless, highly vascularized, releases hormones into surrounding tissue fluid

three special features of the endocrine system

thyroid, adrenal, pituitary, pineal, parathyroid

list the endocrine glands (TAPPP)

pancreas, ovaries and testes, placenta

other organs containing endocrine tissue

pancreas, adipose cells, thymus, hypothalamus, heart, kidneys, gastrointestinal, gonads

more endocrine tissues and organs (PATHH K GIG)

hypothalamus

what is the neuroendocrine organ?

amino acid or steroidal

what are the two classifications of hormones?

change membrane permeability, stimulate protein synthesis, activate/deactivate enzymes, induce secretion of molecules, stimulate mitosis

5 activities of the endocrine system

humoral, neural, hormonal

3 types of stimuli that trigger the release of hormones

humoral stimulus

altered levels of certain critical ions or nutrients stimulates the release of hormones

neural stimulus

neural input stimulating the release of hormones

hormonal stimulus

trophic hormones stimulate the release of other hormones

specificity

Target cells must have receptors specific to each hormone in order to attract hormone and affect change. This is known as ___________

blood levels of hormones, number of receptors on target cells, affinity of binding between hormone and receptor

response of target cells to hormones depends on:

dynamic

receptors are ___________, meaning they can change in number and affinity

high affinity

receptor has a strong attraction to the hormone and they fit together in a lock and key formation; requires less hormone for activation

low affinity

receptor has a weak attraction to hormone, so it takes more hormone for activation or does not activate at all

freely in blood, rapid

if a hormone is lipid insoluble (amino acid based), it is transported ______________________ and the target organ effect is _______________

with a plasma protein (albumin), hours or days

if a hormone is lipid soluble (steroidal), it is transported in the blood _________________ and the target organ effect takes _______________

permissiveness

in this interaction with target cells, for a full response, there must be more than one hormone (ex: growth and thyroid hormones)

synergism

in this interaction with target cells, more than one hormone produce the same effect, but together have a larger effect (ex: glucagon and epinephrine)

antagonism

in this interaction with target cells, one hormone opposes the actions of another (ex: calcitonin and parathyroid hormone)

pituitary gland

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

hypophysis

another name for the pituitary gland

posterior pituitary lobe

not considered a true endocrine gland, derived from neural tissue; acts as a storage area for hormones made in the hypothalamus (ADH and Oxytocin)

supraoptic nucleus

this area of the hypothalamus sends ADH to the posterior pituitary lobe via the hypothalamic hypophyseal tract

paraventricular nucleus

this area of the hypothalamus makes and sends oxytocin to the posterior pituitary lobe via the hypothalamic hypophyseal tract

oxytocin

hormone made in the paraventricular nucleus of the hypothalamus; released in greater quantities during childbirth and breastfeeding; stimulates uterine contractions and milk ejection

antidiuretic hormone (ADH)

hormone made in the supraoptic nucleus of the hypothalamus; prevents urine formation and dehydration; in instances of dehydration, osmoreceptors alert the supraoptic nucleus to release this hormone to the kidney tubules to reabsorb water

pain, low blood pressure, nicotine, morphine

triggers for the release of ADH

vasopressin

when blood pressure drops dramatically, large amounts of ADH are released and cause vasoconstriction; in these instances, ADH is referred to as:

300 million osm

normal blood osmolarity level

diabetes insipidus

large urine output and intense thirst caused by an insufficiency of ADH

anterior pituitary lobe

true endocrine gland (no neural connection to hypothalamus); vascular connection to hypothalamus via the hypophyseal portal system in the infundibulum; responsible for releasing and inhibiting hormones from the ventral hypothalamus; hormones from hypothalamus control the release of these hormones

TSH, ACTH, FSH, LH

4 trophic hormones of the anterior pituitary lobe

trophic hormones

regulate the secretory action of other endocrine glands which will produce the final (nontrophic) hormones; NOT FINAL HORMONES

growth hormone, prolactin

2 nontrophic hormones released by the anterior pituitary lobe; FINAL HORMONES

Growth Hormone

also called somatotrophin; nontrophic hormone that stimulates most body cells to grow and divide; main targets are bone, skeletal muscle, connective tissue

GHRH, GHIH

secretion of growth hormone (GH) is regulated by __________ and ____________ via a negative feedback mechanism

mobilizes fat deposits for use as fuel, conserves blood glucose by decreasing glucose uptake and use

direct actions of growth hormone (GH) on metabolism

stimulates liver, skeletal muscles, and bone to produce IGFs which stimulate skeletal muscle and bone growth

indirect actions of growth hormone (GH) on metabolism

gigantism

excess growth hormone in children leads to

acromegaly

excess growth hormone in adults results in ________________, causing enlarged feet, hands, and face, thickening of soft tissue, and coarse flaccid features

pituitary dwarfism

idiopathic insufficiency of growth hormone in children causes_________________, which is a type of proportionate dwarfism

slightly accelerated aging, muscle and fat loss, and psychological changes

acquired growth hormone deficiency in adults causes

thyroid stimulating hormone

also called thyrotrophin; trophic hormone that stimulates the development and secretory activity of the thyroid gland; its release is triggered by TRH from the hypothalamus; inhibited by TH and somatostatin

Adrenocorticotrophic hormone

ACTH; trophic hormone that stimulates the adrenal cortex to release corticosteroid hormones; release is stimulated by CRH from the hypothalamus

FSH and LH

gonadotrophins that are absent prior to puberty and induce maturation of the gonads

prolactin

nontrophic hormone that stimulates milk production in females and may enhance testosterone in males; release stimulated by PRH from the hypothalamus and inhibited by PIH (AKA dopamine)

thyroid gland

largest pure endocrine gland in the body; located in anterior trachea below larynx; highly vascularized; hollow spherical follicles produce thyroglobulin; trapped iodide becomes oxidized to I2 and covalently bound to tyrosine residues in thyroglobulin molecules; result is the linkages of MIT and DIT to produce TH

calcitonin

parafollicular cells in the thyroid make:

thyroid hormone

body’s major metabolic hormone, made of thyroxine T4 and triiodothyronine T3; affects almost every cell in the body; increases use of glucose, metabolic rate of cells, heat production, maintains blood pressure, regulates tissue growth and development, and helps with maturation of reproductive organs

hypothyroidism

also called myxedema in adults; caused by defective thyroid, low TSH or TRH, inadequate dietary iodine, or Hashimoto’s thyroiditis; decreases cell metabolism and results in cold, constipation, dry skin, edema, lethargy, and brain fog

cretinism

caused by neonatal hypothyroidism; usually from missing or abnormally formed thyroid gland, pituitary gland failing to stimulate the thyroid, or the defective or abnormal formation of thyroid hormones; causes short, disproportionate body, irreversible mental developmental defects, puffy face, dull look, thick protruding tongue; treated with replacement thyroid hormone and is irreversible

hyperthyroidism

increased cell metabolic activity due to high levels of TH in the blood, most commonly caused by Grave’s disease; causes sweating, increased heart rate, nervousness, weight loss, exophthalmos, tachycardia, arrhythmia, hypertension; usually treated by excision of thyroid gland or radioactive iodine swallow

Grave’s disease

autoimmune disease in which antibodies mimic TSH causing high levels of thyroid hormone in the blood stream

calcitonin

hormone produced by the parafollicular cells of the thyroid gland; thought to play a role in bone remodeling in adults and bone growth in children; lowers blood calcium and phosphate, decreases osteoclast activity and stimulates osteoblasts; used to treat Paget’s

parathyroid glands

small glands on the posterior thyroid that secrete PTH

parathyroid hormone

most important hormone for regulating blood calcium; falling blood calcium levels stimulate its release and increased blood calcium inhibits it; targets the skeleton, kidneys, and intestines; stimulates osteoclasts to break down bone and release calcium into the bloodstream; causes decreased loss of calcium in urine and increased calcium absorption from the intestine

hyperparathyroidism

“stones, bones, abdominal moans, psychiatric overtones” refers to a slew of symptoms associated with this pathology of the parathyroid glands: kidney stones, bone pain from easily fractured soft bones, weak skeletal muscles, peptic ulcers, CNS symptoms, confusion, and lethargy; most likely cause is parathyroid tumor

hypoparathyroidism

usually a result of thyroid excision or trauma to parathyroid glands; symptoms associated with resulting decrease in blood calcium levels include muscle twitches, excitable neurons, and loss of sensation

adrenal glands

pyramid shaped glands sitting on top of the kidneys that secrete hormones that help us deal with extreme stress

adrenal cortex

true endocrine portion of the adrenal glands; arranged in 3 distinct layers: zona glomerulosa, zona fasciculata, and zona reticularis

zona glomerulosa

layer of adrenal cortex that produces mineralocorticoids and controls the balance of minerals and water in the blood

zona fasciculata

layer of adrenal cortex that produces glucocorticoids and influences cell metabolism to resist stress

zona reticularis

layer of adrenal cortex that produces gonadocorticoids (mainly androgens)

mineralocorticoids

steroid hormones secreted from adrenal cortex that regulate electrolyte concentrations (especially Na+ and K+), most abundant of which is aldosterone

aldosterone

most potent and abundant mineralocorticoid secreted by the adrenal cortex; maintains electrolyte balance, stimulates Na+ reabsorption, K+ secretion; primary target is kidney tubules; secretion is stimulated by increased blood K+, decreased blood Na+, and decreased blood volume and pressure; inhibited by decreased blood K+, increased Na+, and increased blood volume and pressure

increased blood K+, decreased blood Na+, decreased blood volume and pressure

triggers for secretion of aldosterone

decreased blood K+, increased Na+, increased blood volume and pressure

triggers for inhibition of aldosterone

aldosteronism

hypersecretion of aldosterone; excess Na+ secretion causes excess fluid volume, hypertension, and edema; excess K+ secretion causes muscle weakness, decreased neuron activity, and paralysis

Addison’s disease

hyposecretion of aldosterone and cortisol that causes either low Na+ or low K+, hypotension, dehydration, and is treated with HRT

glutocorticoids

hormones produced in the adrenal cortex that help regulate metabolism to resist stress and help the body adapt to intermittent food intake by keeping blood sugar and blood volume constant; levels increase in times of high stress; most important of these hormones is cortisol

cortisol

also called hydrocortisone; important glucocorticoid hormone that creates glucose from fats and proteins, breaks down proteins and reuses amino acids, works with adrenaline to increase blood pressure for rapid delivery of fuel to cells; peaks in the morning and is lowest right before bed; becomes very active during times of high stress

Cushing’s disease

condition resulting from excess cortisol from pituitary or adrenal cortex tumor or clinical doses of cortisol; results in muscle and bone loss, water and salt retention, hypertension and edema, distribution of fat to posterior neck, and the possibility of severe infections

gonadocorticoids

mostly androgens like testosterone, play a role in the onset of puberty, and sex drive in women; amount secreted by adrenal cortex is insignificant compared to amounts produced by gonads

adrenal medulla

middle portion of the adrenal glands that secretes epinephrine and norepinephrine into blood; not true endocrine tissue, but sympathetic nervous tissue; responsible for producing fight or flight response; release of E and NE results in increased heart rate, blood sugar, metabolic rate, and vasoconstriction

pancreas

organ located behind the stomach; has both endocrine and exocrine functions; islets in this organ (islets of Langerhan’s) contain two kinds of hormone producing cells: alpha (produce glucagon) and beta (produce insulin)

glucagon

pancreatic hormone that stimulates the release of glucose into the bloodstream; mainly targets the liver and causes the breakdown of glycogen into glucose

insulin

pancreatic hormone that lowers glucose levels in the blood (by increasing the transport of blood glucose to muscle and fat cells); increases tissue’s ability to take up glucose and amino acids; excess glucose is stored as glycogen in skeletal muscle and liver and as fat in adipose tissue

diabetes mellitus

condition caused by insufficient insulin; results in glucose staying in the blood, which starves the body cells of fuel, leading to the breakdown of fat instead of glucose; causes hyperglycemia, nausea, glucose in urine, increased urine production, lethargy, fatigue, irritability, hyperosmolarity of blood

oral glucose tolerance test

test used to check for type two diabetes

60-100 mg/dL

normal fasting blood glucose values

less than 200 mg/dL

normal blood glucose levels 1 hour after eating

less than 140 mg/dL

normal blood glucose values 2 hours after eating

between 140-200 mg/dL

fasted blood glucose levels indicating pre-diabetes

over 200mg/dL

fasted blood glucose levels indicating diabetes mellitus

type 1 diabetes

insulin dependent diabetes affecting 3% of people with diabetes; decreased insulin secretion developing from autoimmune destruction of pancreatic islets; symptoms usually only appear after 90% of pancreatic islets have been destroyed; manifests most commonly in young people and is treated with insulin injections

type 2 diabetes

non-insulin dependent diabetes affecting 97% of people with diabetes; tissues cannot respond to insulin; direct cause remains unknown but there is a high genetic component and is commonly associated with obesity; affects people between 40-45 and is treated with insulin and diet

pineal gland

endocrine gland located beneath the third ventricle of the brain; secretes melatonin, which induces drowsiness and reaches peak levels in the evening

thymus

endocrine gland located in the thorax; is large in infants and children and shrinks with age (becomes adipose and connective tissue); produces thymopoietins and thymosins and is involved in the development of T-cells

heart

produces atrial natriuretic peptide hormone that works at the kidney tubule to increase “salty” urine and decrease blood volume

atrial natriuretic peptide

hormone secreted by the heart that works at the kidney tubules to increase “salty” urine and decrease blood volume

kidney

secretes erythropoietin, which signals the bone marrow to increase the production of red blood cells

erythropoietin

hormone secreted by the kidneys that stimulates the bone marrow to produce more red blood cells

adipose tissue

tissue that releases leptin into the blood that binds to the ventral medial nucleus of hypothalamus and signals satiety;

adiponectin

hormone secreted by adipose tissue that increases cells’ sensitivity to insulin

leptin

hormone secreted by adipose tissue that binds to the ventral medial nucleus of the hypothalamus to signal satiety