Exam 1 - Endocrine System Flashcards
describe the endocrine system
endocrine glands and cells are located throughout the body and play an important role in homeostasis
which 2 systems control all physiological processes?
nervous system and endocrine system
describe the way the nervous and endocrine system work to deliver their messages
nervous system: exerts point-to-point control through nerves; nervous control is electrical by nature and FAST
endocrine system: broadcasts its hormonal messages to essentially all cells by secretion into blood and extracellular fluid; cells MUST BEAR A RECEPTOR for the hormone
define hormones
long distance chemical signals that travel in blood or lymph fluids
OR
chemical substances secreted by cells into extracellular fluid to regulate a metabolic function
define autocrines and paracrines
autocrines: chemicals that exert effects on the same cells that secrete them
paracrines: locally acting chemicals that affect cells other than those that secrete them
describe endocrine glands
ductless glands
what hormones are produced by
hormones enter blood stream or lymph fluid
what are the types of cellular changes that hormones can produce in target cells?
alter plasma membrane permeability by opening/closing ion channels
stimulate protein synthesis
activate or deactivate enzyme systems
induce secretory activity
stimulate mitosis
name the 2 types of hormones
amino acid based and steroid based hormones
describe amino acid based hormones
make up the majority of all hormones
includes amines, thyroxine (T3 & T4), peptide, water soluble, and protein hormones
second messengers: cAMP, DAG, IP3, Ca++
binds to receptor on plasma membrane
describe steroid based hormones
made from cholesterol
includes gonadal (testosterone and estrogen) and adrenocortical hormones (aldosterone, cortisol, & androgens) *sex hormones and adrenal cortex hormones)
bind to intracellular receptors
name the 2 mechanisms used by hormones to alter target cell activity
second messenger system
direct gene activation
describe the second messenger system
for water soluble/amino acid based hormones
cannot enter target cells alone
use G protein coupled receptors on plasma membrane of cell to transmit intracellular response (cAMP, DAG, IP3, Ca++)
describe direct gene activation
for lipid (fat) solube hormones (steroid and thyroid)
act directly on intracellular receptors which activates genes
phosphodiesterase
quickly degrades G protein cAMP
describe insulin
an amino acid based hormone, BUT it does not require a second messenger system
binds to receptor TYROSINE KINASE on plasma membrane
describe thyroxine & triiodothyronine
thyroid hormone; T4 AND T3
EXCEPTION TO THE AMINO ACID BASED HORMONE RULES
acts like a steroid hormone by diffusing easily into cell and binding to an intracellular receptor (taken to DNA for protein synthesis)
major metabolic hormone; increases the metabolic rate and body heat production by stimulating enzymes used in glucose metabolism
other roles: maintenance of blood pressure, regulation of tissue growth, development of skeletal and muscle systems, reproductive capabilities
describe the blood calcium figure 8
blood calcium increases, thyroid gland releases parafollicular cells (c cells), calcitonin is produced, osteoblasts are stimulated causing calcium to be deposited into bone from blood, result: decreased calcium in blood stream
blood calcium decreases, parathyroid glands release chief cells, parathyroid hormone (PTH) aka parathormone is produced, osteoclasts are stimulated causing bone to be broken down into calcium and deposited into the blood, result: increased calcium in blood stream
average blood calcium level
9-11 mg/dl
describe the blood glucose figure 8
blood glucose increases, pancreas releases beta cells (B cells), insulin is produced, attaches to RECEPTOR:TYROSINE KINASE & glucose enters cells (liver, muscle, fat), result: decreased glucose in blood stream
blood glucose decreases, pancreas releases alpha cells (fish cells), glucagon is produced, sent to liver to break down glycogen, result: increased glucose in blood stream
average blood glucose level
70-110 mg/dl
what kind of cells do hormones activate?
target cells
define target cells
must have specific receptors that the hormones can bind to
may be intracellular (steroid based) or located on the plasma membrane (amino acid/protein/peptide/water soluble based)
name the 3 factors that target cells depend on for activation
blood levels of the hormone
relative number of receptors on the target cell
the strength of those receptors for the hormone
define up-regulation
target cells form more receptors in response to hormone
define down-regulation
target cells lose receptors in response to prolonged hormone exposure
hormones are controlled by
negative feedback
blood calcium and blood glucose levels are controlled by
humoral stimuli
the adrenal medulla and its production of epinephrin (adrenaline) and norepinephrin (noradrenaline) is controlled by
neural stimuli
the hypothalmus and pituitary are controlled by
hormonal stimuli
master switchboard
hypothalmus
hypopheseal portal system
blood vessels that run from the hypothalmus to the anterior pituitary
how hormones from the hypothalmus reach the anterior pituitary
what are the hormones called that are sent through the hypopheseal portal system
releasing and inhibiting hormones
hypothalmic hypopheseal tract
aka infundibulum “stalk”
aka nerve tract
“funnel”
how hormones from the hypothalmus are sent to the posterior pituitary to be stored and released
name all of the major endocrine glands
pituitary (hypophysis) thyroid gland parathyroid glands adrenal glands pancreas gonads pineal gland thymus
master gland
anterior pituitary
describe the posterior pituitary
aka neurohypophysis
made of neural tissue and the infundibulum
receives, stores, and releases 2 hormones from the hypothalmus
describe the anterior pituitary
aka adenohypophysis
made up of glandular tissue
manufactures and releases 7 hormones
name and describe the types of hormones manufactured and released by the anterior pituitary
tropic hormones: going to cause change in another endocrine gland; use NEGATIVE FEEDBACK to maintain homeostasis and decrease their release
- FSH - follicule stimulating hormone (sperm/egg)
- LH - luteinizing hormone (testosterone/estrogen & progesterone)
* *^gonads^** - ACTH - adrenocorticotropic hormone
- TSH - thyroid stimulating hormone
direct hormones: go directly to cells/tissue; release is decreased by INHIBITING HORMONES exception to negative feedback
- Growth hormone
- Prolactin (produces milk)
- MSH - melanocyte stimulating hormone
describe growth hormone
also known as somatotropin
stimulates liver, skeletal muscle, bone, and cartilage to produce growth factors
growth factors: amino acid absorption, protein synthesis, and increased growth
release of GH increases the breakdown of glycogen and fats which are stored for fuel
describe the effects of hypersecretion and hyposecretion of GH
hypersecretion: usually results from an anterior lobe tumor
in children/before plates close: gigantism
in adults/after plates close: acromegaly - enlarged extremities
hyposecretion:
in children: pituitary dwarfism (can be treated with GH injections, but could result in fluid retention, joint/muscle pain, diabetes, and possibly cancer)
in adults: no major problems
describe prolactin
stimulates milk production
stimulated by estrogen & PRH
role in males not well understood
name the hormones stored and released by the posterior pituitary
OT - oxytocin
ADH - antidiuretic hormone
describe oxytocin
uterine contractions milk "let down" sexual arousal/orgasm "cuddle hormone" promotes nurturing/affectionate behavior *regulated by POSITIVE FEEDBACK pitocin is artificial form
describe ADH
H20 reabsorption
hypothalmic osmoreceptors respond to changes in the solute concentration of the blood
high solute conc/low water: ADH is synthesized and released, inhibiting urine formation (keeping water in)
low solute conc/high water: ADH is not released, allowing water loss
vasopressin/vasoconstriction of visceral blood vessels
targets renal tubules of kidneys; ADH causes these ducts to reabsorb more water during times of high solute levels
describe the effects of hypersecretion and hyposecretion of ADH
hypersecretion:
in children with meningitis; following neurosurgery, trauma, or secreted by cancer cells
after general anesthesia: can lead to SIADH (syndrome of inappropriate ADH secretion)
hyposecretion:
can result in diabetes insipidus
huge urine output; intense thirst
describe the process of the hormonal stimuli chart
the hypothalmus will either use the hypothalmic hypopheseal tract (to pp) or the hypopheseal portal system (to aa)
option 1: OT or ADH will be released
option 2: negative feedback for tropic hormones (FSH, LH, ACTH, TSH) or releasing hormones for direct hormones (GH, prolactin, MSH) to be released
hormones are released to find target gland
target gland releases target hormone (from thyroid, adrenal cortex, or gonads)
negative feedback for tropic hormones/inhibiting hormones for direct hormones
hormones sent to target cells
name the inhibiting and releasing hormones and their anterior pituitary matches
GnRH (gonadotropin releasing hormone)»_space; FSH & LH
CRH (corticatropin releasing hormone»_space; ACTH
TRH (thyroid releasing hormone)»_space; TSH
GHRH (growth hormone releasing hormone) & GHIH (growth hormone inhibiting hormone)»_space; GH
PRH (prolactin releasing hormone) & PIH (prolactin inhibiting hormone)»_space; PRL
describe the thyroid gland
located in the neck where it wraps around the trachea
produces thyroid hormone (t4 and t3)
describe the effects of hypersecretion and hyposecretion of TH
hyperthyroidism:
Grave’s disease - autoimmune disease; overproduction of antibodies that resemble TSH
- elevated metabolic rate, sweating, rapid/irregular heartbeat, nervousness, weight loss, bulging eyes
hypothyroidism:
(in adults) Myxedema - lack of iodine; low metabolic rate, chilled, constipation, thick/dry skin, puffy eyes, edema, lethargy, mental sluggishness
(in kids) Cretinism - mental retardation, disproportionate body, thick tongue and neck
describe the parathyroid glands
4-8 tiny glands located in the posterior thyroid
chief cells produce parathyroid hormone
PTH is the most important hormone is calcium homeostasis
describe the effects of hypersecretion and hyposecretion of PTH
hyperparathyroidism: rare; due to a tumor
bones soften and deform (osteitis fibrosa cystica)
elevated blood calcium depress nervous system and contribute to the formation of kidney stones (calculi)
hypoparathyroidism:
following gland trauma or removal (or prolonged Mg deficiency)
increases excitability of muscles; results in tetany, respiratory paralysis, and possibly death
describe the adrenal glands
both adrenal glands sit atop the kidneys and are composed of an outer cortex and inner medulla
*the cortex is subdivided into additional zones
name the 3 layers of the adrenal cortex & their hormones
- Guys Fight Regularly*
- AL, CORey, & ANDRew*
zona glomerulosa - ALdosterone
zona fasciculata - CORtisol
zona reticularis - ANDRogens
describe aldosterone
produced by the zona glomerulosa
MINERALcorticoid
reabsorption/water retention in kidneys, Na+ resorption & K+ secretion, increase blood pressure, increase blood volume
mineralcorticoid
regulate electrolytes (usually Na+ and K+)
effect volume of blood and ECF
describe the effects of hypersecretion and hyposecretion of aldosterone
hypersecretion:
aldosteronism
due to adrenal tumors
hypertension and edema due to excessive amounts of Na+
excretion of K+ leads to abnormal function of neurons and muscles, possibly coma & death
hyposecretion:
usually along with hyposecretion of glucocorticoids
Addisons’s disease - weight loss, glucose & Na+ levels drop, K+ levels rise
dehydration and hypotension
treated with corticosteroid replacement therapy
describe cortisol
primary hormone during long term stress
produced by the zona fasciculata
in response to ACTH, patterns of eating/activity, stress
GLUCOcorticoid
increases blood glucose, decreases inflammation, weakens immune system
(the more stress you’re under, the more cortisol is produced, the more your immune system is weakened)
glucocorticoids
keep blood glucose levels relatively constant
maintain blood pressure
major group released especially during long term stress
describe the effects of hypertension and hypotension of glucocorticoids
hypersecretion:
Cushing’s Syndrome -
depressing cartilage and bone formation
anti-inflammatory and anti-immune effects
promotes changes in cardiovascular, neural, and GI function
loss in muscle and bone protein, water and salt retention leading to higher BP and edema (swelling)
hyposecretion: Addison’s Disease (along with deficit of mineralcorticoids)
describe androgens
produced by the zona reticularis
GONADocorticoid
male sex hormones, testosterone onset to puberty
appearance of secondary sex characteristics
can be converted into estrogen for females, only source of testosterone in females
gonadocorticoids
most are androgens
converted into testosterone or estrogen
released from the gonads during puberty
describe the effects of hypersecretion of gonadocorticoids
adrenogenital syndrome (masculinization)
males: rapid maturation of the reproductive organs and secondary sex characteristics in young males; generally not visible
females: hair growth in areas associated with males; clitoris can elongate to resemble a small penis
describe the adrenal medulla
made up of chromaffin cells that seceret 80% epinephrin & 20% norepinephrin
production stimulated by the sympathetic nervous system in response to short term stress
increased bp & heart rate, blood diversion from digestive system to brain, heart, skeletal muscle, etc.
prep for fight or flight
describe the pancreas
(excocrine function) acinar cells secrete a digestive enzyme that travels to the small intestine through the pancreatic duct
(endocrine function) secretion of insulin and glucagon; these regulate the rate of glucose metabolism in the body
name the hormones secreted by the pancreas
glucagon and insulin
describe glucagon
hyperglycemic agent - raises blood glucose levels
its major target is the liver where it promotes:
release of glucose into the blood from liver cells
works in opposition to insulin
glycogenolysis: the breakdown of glycogen into glucose
gluconeogenesis: synthesis of glucose from non-carbohydrates
controlled by negative feedback
describe insulin
hypoglycemic agent: lowers blood glucose levels
effects:
enhances membrane transport of glucose into fat and muscle cells
inhibits glycogenolysis and gluconeogensis
controlled by negative feedback
describe the effects of hypersecretion and hyposecretion of insulin
hyperinsulinism: hypoglycemia, disorientation, unconsciousness
hyposecretion: results in diabetes mellitus
1. polyuria - huge urine output; excess glucose by osmosis pulls water out
2. polydipsia - excessive thirst
3. polyphagia: excessive hunger and food consumption
- hyperglycemia; results in glycosuria: output of glucose in urine
- lack of glucose means tissues must use fatty acids for energy; results in high level of fatty acids and their metabolites (aka ketone bodies) i n the blood
- rapid collection of ketone bodies can lead to ketoacidosus: kidney damage/failure, coma, and death
what are the types of diabetes mellitus?
Type 1: insulin dependent
early onset, total lack of insulin production
long term vascular & neural problems such as high cholesterol, risk of vascular diseases, arteriosclerosis, stroke, heart attack, blindness
Type 2: non-insulin dependent
late onset, inadequate amounts of insulin or resistant insulin receptors
90% characterized by overweight
describe the female gonads
paired ovaries in the abdominopelvic cavity
estrogen:
maturation of reproductive organs
appearance of secondary sexual characteristics
thickening of the uterus in preparation for pregnancy
progesterone (& estrogen):
breast development
menstrual cycle
describe the male gonads
testes located in extra-abominal sac (scotum)
testosterone:
initiates maturation of reproductive organs
appearance of secondary sexual characteristics
necessary for sperm production
maintains reproductive organs in their functional state
describe the pineal gland
small gland hanging from the roof of the 3rd ventricle in the brain
produces melatonin:
involved in timing of sexual maturation and puberty
day/night sleep/wake cycle
involved in psychological processes that show rhythmic variations (body temp, sleep, appetite)
describe the thymus
located deep in the sternum
large in children, but shrinks with age
produces thymopoietins and thymosins:
essential for the development of lymphocytes (T cells) in the immune system
