Term
|
Definition
- regulatory system
- transmits electrical impulses to skeletal muscles and exocrine glands
- system is "wired" (short): sends electrical signals through distinct, highly organized pathways; rapid
- these pathways are interconnected (anatomically connected) therefore affect other systems
- messenger is neurotransmitter |
|
|
Term
|
Definition
- regulatory system
- secretes hormones (chemical messengers) into the circulating blood to distant sites in the body (anatomically distinct sites)
- glands are NOT connected; rather, scattered throughout the body
- DO NOT HAVE DUCTS
- target cells that have receptors specific to the hormone used as a messenger
- slow; long in duration; influences other systems |
|
|
Term
|
Definition
|
|
Term
|
Definition
- release neurohormones
- adrenal glands
- also distributed by the bood to target cells
- mix between nervous stimulation and endocrine hormone secreted |
|
|
Term
| Fxs of the endocrine system |
|
Definition
- regulates organic metabolism and water/electrolyte balance (i.e. antidiuretic)
- induces adaptive changes to deal with stress
- promotes smooth, sequential growth and development (i.e. hormone)
- controls reproduction (i.e. testosterone and estrogen)
- regulates RBC production
- regulates circulatory and digestive Fxs |
|
|
Term
|
Definition
- regulates secretions of another endocrine gland
- i.e. tropic hormones are secreted by the anterior pituitary gland |
|
|
Term
| contribution of hormones to the complexity of endocrine system |
|
Definition
- one endocrine gland can produce multiple hormones
- a single hormone can be produced by more than one endocrine gland and have more than one type of effect (b/c it has more than one target cell)
- a single target cell can be influenced by more than one hormone b/c diff. receptors allow diff. responses by tissue
- rate of secretion of a hormone can vary over time (female repro. cycle)
- same chemical messengers can be a hormone or neurotransmitter (e.g. norepinephrine)
- some organs have exclusively endocrine Fxs.; others (e.g. testis) have endocrine and nonendocrine Fxs. |
|
|
Term
|
Definition
1. proteins
2. amines
3. steroids |
|
|
Term
|
Definition
- proteins
- shorter chains
- aa in chains of varying length
- majority of hormones
- secretory vesicles pinched off and stored in cytoplasm
- hormones released from endocrine cells by exocytosis - rate of secretion is controlled by regulation of release of presynthesized stored hormone
- synthesis |
|
|
Term
| synthesis of peptide hormones |
|
Definition
- have precursors = preprohormones
- made on ribosomes of the ER
- converted to prohormones and, finally, active hormones in the Golgi complex
- golgi complex concentrates active hormone into secretory vesicles |
|
|
Term
|
Definition
- cholesterol derivatives are common precursor
- series of enzymatic steps modify cholesterol into a different hormone in a specific endocrine cell
- specificity is due the enzymes present in the specific steroidogenic organ
- only precursor stored; the lipid-soluble hormone is not stored
- once formed, lipid-soluble hormones diffuse through steroidogenic cell's lipid plasma membrane and enter blood
- rate of secretion is controlled by rate of hormone syntesis
- once these hormones get into the blood they are lipophilic therefore do not travel well through the blood - need carriers - can be converted into more potent hormones |
|
|
Term
|
Definition
- derived from the aa tyrosine
- secreted by the adrenal medulla (and thyroid)
- proteins/peptides and amines (except TH which are not hydrophilic) are hydrophilic (water-soluble) hormones
- are stored until they are secreted
- secretion by endocytosis and exocytosis |
|
|
Term
|
Definition
- all hormones are transported in the blood
- they are not transported in the same way |
|
|
Term
| transport of hydrophilic hormones |
|
Definition
- peptide and catecholamines
- dissolved in the plasma
- solubility in aqueous environment therefore transported by the blood |
|
|
Term
| transport of lipophilic hormones |
|
Definition
- TH and steroid hormones
- bound reversibly to plasma proteins
- bind reversibly because they can't do their job attached to proteins
- released by plasma proteins when they actively signal target cells |
|
|
Term
| In general, how do hormones produce their effects? |
|
Definition
| - by alternating itracellular proteins |
|
|
Term
| How do hydrophilic hormones produce their effects? |
|
Definition
- bind to a receptors on the surface of target cells
- a few hydrophilic hormones alter the permeability of the target cell's membrane
- most activate second messanger which changes pre-existing activity in the target cell |
|
|
Term
| How do lipophilic hormones produce their effects? |
|
Definition
- pass through targte cell membranes readily and bind to receptors inside the target cell
- activate specific genes which activates hormone production |
|
|
Term
| How do hydrophilic hormones activate second-messanger systems? |
|
Definition
- bind to receptor on target cell surface
- binding activates an intermediate G protein
- this activates adenylylcyclase, which converts intracellular ATP to cyclic AMP (cAMP)
- cAMP triggers steps that alter the activity of a protein (often an enzyme - kinase)
- this produces a physiological response in the target cell
- STUDY FIGURE |
|
|
Term
| how do lipophilic hormones stimulate a gene thus promoting protein synthesis? |
|
Definition
- hormone passes through the target cell membrane
- binds with an intracellular receptor that binds to DNA, turning on a gene
- gene makes RNA, making a specific protein at the ribosome
- this newly synthesized protein changes the physiological response in the target cell
- STUDY FIGURE |
|
|
Term
| concentration of hormones |
|
Definition
| - subject to control - varies according to homeostatic need |
|
|
Term
| what determines the concentration and availability of hormones to receptors? |
|
Definition
- rate of secretion
- transport (e.g. extent of binding to plasma proteins, if it is lipophilic)
- rate of metabolic activation; that is, its metabolism
- rate of removal from the blood; that is, its excretion
- removal can be by metabolic inactivation or urinary excretion |
|
|
Term
|
Definition
- maintains the plasma concentration of a hormone at a needed level
- STUDY EXAMPLES IN NOTES |
|
|
Term
| what causes endocrine disorders |
|
Definition
- hyposecretion
- hypersecretion |
|
|
Term
|
Definition
- can be primary or secondary
- too little hormone
- idiopathic
- genes (heredity) - "inborn errors of metabolism"
- dietary deficiency
- chemicals and toxins
- immunologic factors (antibodies)
- diseases processes (e.g. CA - tumors on endocrine gland not subject to normal regulatory control; or TB)
- iatrogenic (caused medically) |
|
|
Term
|
Definition
| - can be primary (abnormal gland) or secondary (due to the deficiency of the hormone's tropic hormone) |
|
|
Term
| target cell responsivness |
|
Definition
- can vary by deliberately regulating the number of hormone-specific receptors (down regulation)
- OR affected by interacting hormones (permissiveness, synergism, or antagonism) |
|
|
Term
|
Definition
- reduction in number of receptors as direct result of elevated hormone concentration
- prevents target cells from overreacting to high [hormone]
- target cells are desensitized to hormone
- ex: DM2 - increased insulin in plasma therefore decreased receptors therefore desensitized |
|
|
Term
|
Definition
- one hormone must be present in sufficient amounts for the full effect of another hormone to occur
- ex: TH increased number of receptors for epenephrine therefore for epinephrine to have full effect, TH must be present |
|
|
Term
|
Definition
- several hormones complement each other and combine effects
- ex: FSH and testosterone combine to make sperm in males |
|
|
Term
|
Definition
- one hormone causes decrease in another hormone's receptors, therefore diminishing the effectiveness of the other hormone
- ex: estrogen increases when females are pregnant therefore decreased receptors for estrogen therefore prevents uterine contraction |
|
|
Term
| Suprachiasmatic nucleus (SCN) |
|
Definition
- master biological clock; serves as a pacemaker for body's circadian rhythms
- cluster of nerve cells bodies in hypothalamus above the optic chiasm
- cyclic changes in their concentration change the neural output from the SCN (block their own transcription)
- changes in neural output produce cyclic changes in effector organs through the day
- daily changes in light intensity are the major environmental cues used to adjust the SCN master clock (receptors in the retina)
- SCN works in conjunction with the pineal gland to regulate circadian rhythms |
|
|
Term
|
Definition
- small, pine-cone shaped structure in the brain
- secretes the hormone melatonin
- melatonin helps keep the body's inherent circadian rhythms in synchrony with the light-dark cycle
- melatonin also increases up to 10-fold during darkness and falls to low levels in ligh (increased melatonin = sleepiness)
- othre neural and blood-borne signals may be involved in the timekeeping in the body |
|
|
Term
|
Definition
- circadian timekeeping
- induces natural sleep w/o side effects of sedatives
- inhibits hormones that stimulate reproductive activity
- effective antioxidant in vitro, helping eliminate biologically damaging free radicals
- may slow aging process by removing free radicals
- appears (speculative) to enhance immunity, reducing age-related shrinkage of thymus (which is the source of T cells) |
|
|
Term
|
Definition
- "hypophysis"
- small structure at the base of the brain |
|
|
Term
| 2 lobes of the pituitary gland |
|
Definition
- neurohypophysis (aka posterior lobe) which is composed of nervous tissue
- adenohypophysis (aka anterior lobe) which is glandular tissue
- STUDY FIGURE ON PAGES 8,9, AND 10 |
|
|
Term
| How do the posterior lobe of the pituitary gland and the hypothalamus act as a unit? |
|
Definition
- connected via neural pathways
- secrete vasopressin (smooths muscle walls; antidiuretic hormone) and oxytocin (stimulate contraction during child birth and promotes milk ejection during breast feeding)
- vasopressin and oxytocin produced by hypothalmic neurons are stored in the neuron terminals in the posterior lobe
- STUDY FIGURE |
|
|
Term
| anterior pituitary (adenohypophysis) |
|
Definition
- synthesizes and secretes six hormones
- synthesizes its own hormones (diff. from posterior)
- vascular network w/in the hypothalamus allows each anterior pituitary hormone to be secreted through signaling by a releasing hormone from this region of the brain
- many hormones are tropic |
|
|
Term
| 6 hormones of the anterior pituitary |
|
Definition
- TSH
- ACTH
- FSH
- LH
- GH
- Prolactin |
|
|
Term
| throid-stimulating hormone (TSH) |
|
Definition
- thryotropin
- tropic
- stimulates the secretion and growth of the thyroid gland |
|
|
Term
| If a hormone is considered tropic, what does this mean? |
|
Definition
| - it regulates the secretion of another gland |
|
|
Term
|
Definition
- somatotropin
- [increased] even in adults
- regulates overall body growth
- important in intermediary metabolism
- liver production of simatonedins
- some consider GH tropic |
|
|
Term
| adrenocorticotropic hormone (ACTH) |
|
Definition
- adrenocorticotropin
- tropic
- stimulates the growth and secretion of hormones from the adrenal cortex |
|
|
Term
| follicle stimulating hormone |
|
Definition
- stimulates growth and development of ovarian follicles in females; sperm production in males
- tropic |
|
|
Term
|
Definition
- tropic
- stimulates ovulation and luteinization (female)
- stimulates testosterone secretion (males) |
|
|
Term
|
Definition
- enhances breast development in females
- not entirely clear on Fx in males, but plays a role in refractory period after ejaculation |
|
|
Term
|
Definition
| - hypothalamic releasing and inhibiting hormones regulate anterior pituitary hormone secretion |
|
|
Term
| 7 types of hypothalamic releasing and inhibiting hormones |
|
Definition
- TRH
- CRH
- GnRH
- GHRH
- GHIH
- PRH
- PIH |
|
|
Term
|
Definition
- thyrotropin releasing hormone
- stimulates the release of TSH |
|
|
Term
|
Definition
- corticotropin releasing hormone
- stimulates the release of ACTH |
|
|
Term
|
Definition
- glucotropin releasing hormone
- stimulates the release of FSH and LH |
|
|
Term
|
Definition
- growth hormone releasing hormone
- stimulates the release of the GH |
|
|
Term
|
Definition
- growth hormone inhibiting hormone
- inhibits the release of the GH and TSH |
|
|
Term
|
Definition
- prolactin releasing hormone
- stimulates the release of prolactin |
|
|
Term
|
Definition
- prolactin inhibiting hormone
- inhibits release of prolactin |
|
|
Term
| chain of command in hypothalamic hormones |
|
Definition
- involved in a 3-hormone chain of command
- mnay hypothalamic hormones have more than one effect
- a single anterior pituitary hormone may be regulated by two or more hypothalamic hormones
- rate of secretion in response to two or more signals depends upon concentraion of signals and intensity of other regulatory input
- these hormonal chemical messengers are produced in many brain areas outside the hypothalamus
- STUDY FIGURE |
|
|
Term
| hypothalamic-hypophyseal portal system |
|
Definition
- hypothalamic regulatory hormones reach the anterior pituitary by a vascular link, a capillary to capillary connection, the hypothalamic-hypophyseal portal system
- blood in this system carries hypothalamic signals to the anterior pituitary
- hypothalamic hormones are delivered directly and at high concentrations to anterior pituitary quickly |
|
|
Term
| control of hypothalamic hormones |
|
Definition
- regulation of the secretion of hypothalamic hormones depends on numerous inputs
- complete regulation is not well understood in some; others are
- target gland hormones inhibit hypothalamic and anterior pituitary hormone secretion via negative feedback
- ex: if cortisol from the adrenal cortex can feed back and reduce CRH secretion (hypothalamus) and the sensitivity of the ACTH secreting cells (anterior pituitary) to CRH; if cortisol falls in the blood, the direction of the other responses is reversed (decresed sensitivity = decreased response = decreased ACTH = decreased cortisol)
- STUDY FIGURE |
|
|
Term
| endocrine control of growth |
|
Definition
- growth of signal by GH, but GH not the sole factor
- GH does not play a role in fetal development (placental Fx) |
|
|
Term
| factors other than GH contributing to growth |
|
Definition
- genetics
- adequate diet
- freedom from chronic disease and stress
- normal levels of other growth-influencing hormones (ex: permissive hormones)
- growth req. net protein synthesis |
|
|
Term
|
Definition
- postnatal growth spurt
- pubertal growth spurt - GH and androgens contribute |
|
|
Term
|
Definition
- estrogen in females
- testosterone in males |
|
|
Term
|
Definition
- androgens
- imapct cell division therefore increase cell growth |
|
|
Term
| intermediary metabolic effects of GH |
|
Definition
- mobilizes fat stores as a major energy source
- increases [blood glucose] levels by decreasing glucose uptake by muscles
- conserves glucose for glucose-dependent tissues (such as brain)
- important for maintaing body during prolonged fasting or times when body's energy needs exceed glucose stores
- promotes growth in both soft tissues and skeleton |
|
|
Term
| ways that GH promotes growth in both soft tissues and skeleton |
|
Definition
- by signaling an increase in the number of cells (hyperplasia) and increase in size of cells (hypertrophy) in target organs
- stimulates cell division and prevents apoptosis (cell #)
- stimulates the uptake of AA and protein sythesis in target cells (cell size) |
|
|
Term
| bone (what is it and what are the parts) |
|
Definition
- bone is connective tissue
- cells and extracellular organic matrix (collagen fibers in mucopolysaccharide-rich semisolid gel) aka the "ground substance"
- osteoblasts
- diaphysis
- epiphysis |
|
|
Term
|
Definition
- precipitation of calcium within matrix
- cartilage is like bone, but it is not calcified (lacks precipitate) |
|
|
Term
|
Definition
| - cell that produces organic matrix |
|
|
Term
|
Definition
- long bone shaft
- ex: femur - do a lot of growing towards height |
|
|
Term
|
Definition
- flared, articulating knob at end of long bone
- growing bone; diaphysis separated from epiphysis by layer of cartilage called the "epiphyseal plate" which is where growth occurs |
|
|
Term
|
Definition
- stimulates growth in the length and thickness of long bones
- comes from hyperplasia and hypertrophy at the epiphyseal plate |
|
|
Term
| how does GH stimulate bone lengthening |
|
Definition
- stimulates osteoblast activity and the proliferation of epiphyseal cartilage(condrocytes - these divide at epiphyseal plate)
- new bone tissue replaces cartilage in this region for diaphysis
- STUDY FIGURE |
|
|
Term
| how does GH stimulate bone thickening? |
|
Definition
| - by activating osteoblasts under the periosteum (new bone surround old bone) |
|
|
Term
| fxs of GH (other than metabolic) |
|
Definition
- exerts effects indirectly by stimulating somatomedins, also called insulin-like growth factors
- IGF-I
- IGF-II |
|
|
Term
|
Definition
- stimulated by GH and mediates most of the growth-promoting effects of GH
- main source is liver
- production depends on adequate nutrition
- production also age-dependent (increased age = increase IGF-I) |
|
|
Term
|
Definition
- production not dependent upon GH
- "intermediary"
- important in fetal development (not under influence of GH) |
|
|
Term
|
Definition
| - regulated by GHRH and GHIH |
|
|
Term
| factors influencing GH secretion |
|
Definition
- increases one hour after a deep sleep (diurnal rhythm)
- increase in exercise = increase secretion of GH
- hypoglycemia = increased secretion of GH
- increased blood AA = increase secretion of GH
- increased stress = increased secretion of GH
- decreased blood fatty acids = increased secretion of GH
- STUDY FIGURE |
|
|
Term
| GH-associated abnormalities that occur when there is a DEFICIENCY of GH |
|
Definition
- childhood hyposecretion produces dwarfism (decresed skeletal growth due to decreased GH)
- in Laron dwarfism, tissues fail to respond to GH (receptor failure)
- pygmies - lack of somatomedins (IGFs)
- adults - reduces muscle mass and strength (due to exercise, stress, etc) |
|
|
Term
| GH-associated abnormalities that occur when there is an EXCESS of GH |
|
Definition
- childhood hypersecretion; produces gigantism; VERY RARE; often results from benign tumors but can be a genetic disorder
- if hypersecretion occurs after the epiphyseal plates have closed, acromegaly develops |
|
|
Term
|
Definition
- hypersecretion of GH
- most obvious in extremities (hands and feet) and face (jaws and cheekbones)
- of course this also occurs with excress exogenous GH (athletes) |
|
|
Term
| hormones other than GH responsible for normal growth |
|
Definition
- TH - permissive role in skeletal growth
- insulin - a growth promoter
- androgens - role in pubertal growth spurt; protein synthesis |
|
|
Term
| 4 types of peripheral endocrine glands |
|
Definition
- thyroid
- adrenal glands
- endocrine pancreas
- parathyroid glands |
|
|
Term
| overview of the thyroid gland |
|
Definition
- lies over the trachea, below larynx
- two lobes of endocrine
- regulates overall basal metabolic rate
- tissue "butterfly"
- major secretory cells are the follicular cells
- also contain C cells |
|
|
Term
| follicular cells of the thyroid gland |
|
Definition
- ring of follicular cells enclose inner lumen filled with colloid
- colloid serves as EC storage site of TH
- Thyroglobulin (TGB) main constituent of colloid, with TH incorporated into TGB
- produce T4 (tetraiodothyronine or thyroxine) and T3 (tri-iodothyronine) which make up the TH |
|
|
Term
| what are C cells in the thyroid gland? |
|
Definition
- cells that make up the interstitial space bt follicular cells
- secrete calcitonin
- plays a role in Ca2+ metabolism |
|
|
Term
| why do you need to store TH? |
|
Definition
| - b/c they are lipophilic and must be stored w/in a protein (TGB) in the colloid |
|
|
Term
|
Definition
- TGB released into colloid space by exocytosis
- tyrosine is incorporated in TGB and end up in colloid
- iodine is transported by the blood to the colloid by follicular cells
- iodine is attached to tyrosine on TGB (resulting in monoiodotyrosine)
- anothre iodine added (di-iodotyrosine)
- coupling of DITs and MITs results in T4 or T3
- a stimulus is transported and follicular cells phagocytize colloid and the phagosome connects with lysosome which increases enzymes which produces appropriate products from T3 and T4 and b/c it is lipophilic they freely diffuse into the blood and transport through transport molecules
- you can recycle iodine to be used in this process again
- STUDY FIGURE |
|
|
Term
|
Definition
- metabolic rate
- cardiovascular
- gastrointestinal
- neuromuscular
- EVERY CELL IN THE BODY IS AFFECTED BY TH |
|
|
Term
|
Definition
- 90% of secreted product is T4, but T3 is 4x more potent
- most of T4 is converted to T3 outside the thyroid
- T4 loses one of its iodines in the liver or kidney
- increases overall basal metabolic rate
- regulates body's use of o2
- calorigenic (heat producing)
- large amt. of secreted hormone converts glycogen into glucose and stimulate protein degradation
- sympathomimetic effects which increase target cells' responsiveness to epinephrine and norepinephrine
- increases heart rate and the force of heart contraction
- stimulates GH secretion and promotes the effect of this hormone on increased protein synthesis |
|
|
Term
| regulation of TH secretion |
|
Definition
- regulated by the hypothalamus-pituitary-thyroid axis
- TSH from the anterior pituitary stimulates the release of the TH
- TSH also maintains the structural integrity of the thyroid gland
- increased TH feeds back to decrease TSH secretion (negative feedback)
- TRH from the hypothalamus turns on TSh secretion
- only known factor to increase TRH secretion is exposure to the cold in newborn infants |
|
|
Term
| abnormal thyroid fx (general) |
|
Definition
- most common endocrine disorder
- two major categories (hypothyroidism - deficient hormone; hyprethryoidism - excessive hormone)
- imbalances in the TH cause changes in development because it has CNS effects |
|
|
Term
|
Definition
- most common cause of hyperthyroidism
- autoimmune disease (body produces Ab to is own proteins)
- Abs (TSI) continuously stimulate TSH receptor
- women > men (5:1)
- age of onset - 20-40yrs. |
|
|
Term
|
Definition
- increased metabolic rate leading to increased perspiration and poor heat tolerance
- decreased body wt. despite increased appetite and consumption
- increased heart rate |
|
|
Term
|
Definition
- radioactive iodine
- surgical removal
- if all removed, supplement with thyroid supplements |
|
|
Term
|
Definition
- extreme form of thyrotoxicosis (life threatening)
- sudden and severe
- fever
- hyperthermia
- tachycardia
- congestive heart failure
- angina (chest pain)
- agitation
- delirium |
|
|
Term
|
Definition
- cooling blankets
- protect heart (beta blockers such as propranolol)
- antithyroid medications |
|
|
Term
|
Definition
- enlarged thyroid gland
- develops when the thyroid gland is overstimulated, either by TSI or TSH
- not very common now (common before because lack of iodine) |
|
|
Term
| role of hypothyroidism in goiters |
|
Definition
- leads to high levels of TSH due do decreased negative feedback
- TSH acts on the follicular cells to increase their size and number |
|
|
Term
| role of hyperthyroidism in goiters |
|
Definition
- grave's disease
- thyroid stimulating immunoglobulin (TSI)
- continuously stimulating thyroid gland therefore growth occurs and it is not controlled by the Ab
- TSI binds with TSH receptors causing this continual stimulation |
|
|
Term
|
Definition
- important for metabolizing nutrients, adapting to stress, maintaining salt balance
- there are two adrenal glands which are imbedded in a capsule of fat on top of each kidney |
|
|
Term
| 2 sections that each adrenal gland has |
|
Definition
- steroid secreting cortex (outer portion of gland)
- catecholamine secreting (epinephrine and norepinephrine) medulla (inner portion) |
|
|
Term
|
Definition
- consists of 3 layers
- each secretes a different family of hormones
- mineralocorticoids influence mineral balance
- glucocorticoids |
|
|
Term
| 3 different zones of the adrenal cortex |
|
Definition
- zona glomerulosa
- zona fasculata
- zona reticuleris
- STUDY FIGURE |
|
|
Term
| families of hormones secreted by the adrenal cortex |
|
Definition
- mineralocorticoids
- glucocorticoids
- sex hormones |
|
|
Term
| how do mineralocorticoids influence mineral balance? |
|
Definition
- regulates volume especially in the circulatory system
- signal the kidneys (distal tubule and collecting duct) to retain Na+ (plus water) and eliminate potassium
- aldosterone secretion is increased by activation of the renin-angiotensin-aldosterone system
- essential to life
- this part of adrenal gland has no ACTH receptors because it is not controlled by ACTH |
|
|
Term
| main glucocorticoid in the adrenal cortex |
|
Definition
|
|
Term
|
Definition
- new glucose production
- e.g the conversion of AA into carbs
- occurs mainly in the liver |
|
|
Term
|
Definition
- stimulate gluconeogenesis
- inhibits glucose uptake mostly by the muscle cells
- stimulates protein degradation
- promotes lipolysis |
|
|
Term
| role of glucocorticoids in adaptation to stress |
|
Definition
- induced by the noxious stimuli
- includes physical, chemical, physiologic, psychological, emotional, and social sources
- e.g. if depressed of psychologically dependent on drugs, increased amt. of glucocorticoids
- increased concentration of glucose in the blood is major response to these stressors |
|
|
Term
| regulation of cortisol secretion |
|
Definition
- regulated by the hypothalamus-pituitary-adrenal cortex axis
- ACTH from the anterior pituitary stimulates the secretion of cortisol from the adrenal cortex
- ACTH secretion triggered by CRH from the hypothalamus
- negative feedback loops from cortisol in the blood to the hypothalamus and the anterior pituitary regulate the level of cortisol in the blood
- other influences include stress and diurnal rhythm
- precursor is cholesterol
- STUDY FIGURE |
|
|
Term
| adrenal cortex: sex hormones |
|
Definition
- androgens and estrogens are produced in both genders
-main production site is in the gonads
- normally amt. produced is not enough to result in masculizing or feminizing effects
- DHEA secretion
- ACTH controls adrenal androgen secretion |
|
|
Term
| Dihydroepiandrosterone (DHEA) |
|
Definition
- only androgen secreted by adrenal cortex with biological importance (can affect females who otherwise lack androgens; males have abundant testosterone which overwhelms DHEA Fx)
- secretion begins at puberty and peaks bt 25-30.
- responsible for pubic and auxillary hair growth, enhancing growth spurt, development and maintenance of female sex drive |
|
|
Term
| primary hyperaldosteronism |
|
Definition
- "conn's syndrome"
- caused by hypersecreting adrenal tumor made up of aldosterone-secreting cells |
|
|
Term
| secondary hyperaldosteronism |
|
Definition
| - caused by high activity of the renin-angiotensin mechanism (due to chronic reduction in blood flow to kidneys; may be caused by narrowing of renal arteries) |
|
|
Term
| symptoms of primery and secondary hyperaldosteronism |
|
Definition
- hypernatremia
- hypokalmeia
- high BP (fluid retention - Na+) |
|
|
Term
|
Definition
| - excessive Na+ retention |
|
|
Term
|
Definition
|
|
Term
|
Definition
- excessive cortisol secretion
- caused by increased amt. of CRH of ACTH, adrenal tumors, or ACTH-secreting tumors elsewhere (paraneoplasic syndrome) |
|
|
Term
|
Definition
- excessive gluconeogenesis resulting from exaggerated effects of glucocorticoids
- increased blood glucose at expense of protein breakdown
- excess glucose deposited in abdomen ("moon face"; "buffalo hump")
- loss of protein leads to muscle wasting and fatigue
- blood vessels weaken, due to lack of structural proteins (collagen)
- poor would healing due to lack of collagen, a major structural protein
- weakened skeleton, due to collagen loss |
|
|
Term
|
Definition
- adrenal androgen hypersecretion
- manifests different effects depending on the biological sex and age of the subject except in adult males which has no affect |
|
|
Term
| symptoms of adrenogenital syndrome in adult females |
|
Definition
| - develop male characteristics: hirsutism, deepening voice, more muscular arms and legs, smaller breasts |
|
|
Term
| Sxs of adrenogenital sydrome in newborn females |
|
Definition
- male-type external genitalia (e.g. clitoris enlarges resembling a penis)
- major cause of female pseudohermaphroditism |
|
|
Term
|
Definition
|
|
Term
|
Definition
| - condition in which ovaries are present but external genitalia resemble male |
|
|
Term
| Sxs of adrenogenital syndrome in prepubertal males |
|
Definition
| - premature development of secondary sexual characteristics (e.g. deep voice, enlarged penis, sex drive, beard) |
|
|
Term
| what is the most common cause of adrenogenital syndrome? |
|
Definition
- enzymatic defect resulting in decreased cortisol and an increase in everything else
- STUDY FIGURE |
|
|
Term
| primary adrenocortical insufficiency |
|
Definition
- "addison's disease"
- usually an autoimmune disease; affecting the whole cortex
- aldosterone and cortisol are deficient (sex hormone not as important) |
|
|
Term
| Sxs of primary adrenocortical insufficiency |
|
Definition
- mineralocorticoids result in potassium retention and sodium/chloride depletion resulting in water loss (hyperalemia) dehydration, hypovolemic shock, orthostatic hypotension
- poor response to stress
- glucocorticoids result in hypoglycemia, lethargy, weakness, fatigue, anorexia, nausea, vomiting
- affects the heart
- may be life threatening because aldosterone essential
- ACTH increased resulting in hyperpigmentation |
|
|
Term
| secondary adrenocortical insufficiency |
|
Definition
- results from abnormality of the pituitary (hypopituitarism) or hypothalamus (tertiary), with insufficient ACTH the result
- only cortisol is deficient because aldosterone not dependent upon ACTH stimulation
- decreased response to stress
- hypoglycemia
- decrease gluconeogenesis
- rapid withdrawl of glucocorticoids vs. common cause (drugs suppress HPA system, causing adrenal cortical atrophy and loss of cortisol) |
|
|
Term
|
Definition
- onset sudden or over a few days
- hypotension and cardiovascular collaspe (shock) result |
|
|
Term
| causes of acute adrenal crisis |
|
Definition
- addison's disease plus exposure to illness or stress
- adrenal hemorrhage due to trauma, anticoagulants, adrenal vein thrombosis, adrenal metastases, meningococcal septicemia |
|
|
Term
| Txs of acute adrenal crisis |
|
Definition
- 5 S's
- salt replacement
- sugar replacement
- steroid replacement
- support physiologic Fxing
- search for and treat underlying cause |
|
|
Term
|
Definition
| - Fx is important in metabolizing nutrients |
|
|
Term
|
Definition
- inner core of the adrenal gland
- modified part of the sympathetic nervois system (making it a modified postganglionic neuron)
- signaled by a preganglionic neuron |
|
|
Term
|
Definition
- stores and secretes epinephrine and norepinephrine (epinephrine is most abundant)
- released into the blood by sympathetic stimulation only making it a neurohormone because it travels through the blood |
|
|
Term
|
Definition
- reinforce sympathetic nervous system and exerts add'l metabolic effects
- fight or flight response
- constricts most blood vessels raising total peripheral resistance
- dilates the blood vessels supplying the heart and skeletal muscles
- promotes glycogenolysis in the liver and skeletal muscles while stimulating glucagon secretion and inhibiting insulin secretion therefore overall increase glucose in the blood
- promotes lipolysis
- causes CNS arousal
- decreased blood supply to systems not used
- increased alertness |
|
|
Term
|
Definition
- pattern of reactions to a situation that threatens homeostasis
- common group of responses ("genearl adaptation syndrome") to noxious stimuli
- sympathetic nervous system and pinephrine play a role
- result in readiness and mobilization of biochemical resources
- cardiac output increases
- blood shunted to heart and skeletal muscles while being diverted away from other organs
- CRH-ACTH-cortisol system activated
- blood glucose increased by decreased insuling and increased glucagon secretions
- renin-angiotensin-aldosterone system and vasopressin maintain BP and blood vol.
- multifaceted stress response is cooridnated by hypothalamus (activates the sympathetic nervous system and CRH-ACTH-cortisol release)
- activation of this response by chronic psychosocial stressor may be harmful because hypoglycemia at expense of energy stores (increase BP, increase blood vol. etc.) |
|
|
Term
| what three areas does the hypothalamus stimulate a response from? |
|
Definition
- posterior pituitary
- SNS
- anterior pituitary
- STUDY FIGURE |
|
|
Term
|
Definition
| - all of the chemical rxns. w/in the cells of the body |
|
|
Term
|
Definition
- "intermediary metabolism"
- degradation, synthesis, and transformation of proteins, carbs, and lipids
- digestions includes macromolecules broken down into smaller absorbable subunites |
|
|
Term
|
Definition
- synthesis of large organic molecules
- "anabolic steroids" - building muscles mass |
|
|
Term
|
Definition
- breakdown of large molecules (digestion0
- rxns. (hydrolysis and glucose oxidation) make ATP
- smaller subunites produced by catabolism can be used for energy or cellular synthesis
- STUDY FIGURE |
|
|
Term
| nutrient storage of glucose |
|
Definition
- nutrients from meals must be stored and released bt meals
- excess circulating glucose is stored as glycogen in the liver and skeletal muscles (limited - once limit is reached, stored as triglycerides in adipose tissue)
- brain needs constant supply of glucose becaue it cannot store glycogen therefore blood glucose of the brain is highly regulated
- when fasting, many body cells burn fatty acids to spare glucose for the brain
- to suppy the brain AA can be converted to gucose by gluconeogenesis |
|
|
Term
| nutrient storage of glucose |
|
Definition
- nutrients from meals must be stored and released bt meals
- excess circulating glucose is stored as glycogen in the liver and skeletal muscles (limited - once limit is reached, stored as triglycerides in adipose tissue)
- brain needs constant supply of glucose becaue it cannot store glycogen therefore blood glucose of the brain is highly regulated
- when fasting, many body cells burn fatty acids to spare glucose for the brain
- to suppy the brain AA can be converted to gucose by gluconeogenesis |
|
|
Term
| nutrient storage of fatty acids and AA |
|
Definition
- excess fatty acids made into triglycerides in adipose tissue
- excess AA made into glucose and fatty acids ult. stored as triglycerides in adipose tissue
- muscles are main site of AA storage via structural proteins
- proteins not first source for E |
|
|
Term
| how long do you store fat? |
|
Definition
|
|
Term
| two functional metabolic states of nutrient storage and use |
|
Definition
- absorptive (fed) state
- postabsorptive (fasting) state |
|
|
Term
|
Definition
- occurs when ingested nutrients are being absorbed into the blood following a meal (approx. 4 hrs)
- metabolic fuels are stored during this state |
|
|
Term
|
Definition
- nutrients are not being absorbed at this time (bt meals)
- metabolic fuels are mobilized during this state
- stored molecules are catabolized to maintain glucose concetration and for E production |
|
|
Term
| what is catabolized during the postabsorptive state |
|
Definition
| fat and glycogen, but glycogen is first |
|
|
Term
| fuel metabolism regulation |
|
Definition
- insulin and glucagon from pancreas regulates fuel metabolism
- pancreas - endocrine cells in pancreas organized into the islets of Langerhans |
|
|
Term
| cells w/in islets of Langerhans |
|
Definition
- beta cells which only produce insulin
- alpha cells which onlyh product glucagon
- somatostasin from pancreatic D cells can inhibit both alpha and beta cells |
|
|
Term
|
Definition
- lowers blood glucose, fatty acid, and AA levels (promotes storage)
- facilitates glucose transport into most cells
- glucose transporter acts as a plasma membrane carrier to accomplish this process
- insulin and this transporter also assist the transport of fatty acids into tissues
- stimulates glycogenesis in skeletal muscle and liver cells
0 inhibits glycogenolysis and gluconeogenesis
- catalyzes the production of fatty acids from glucose (promotes entry of fatty acids from blood into adipose)
- promotes the transport and inc. of AA into cells for protein synthesis |
|
|
Term
|
Definition
- increae in blood glucose concentraion increases insulin secretion (brings blood glucose don to a norm. level)
- decrease in glucose below normal inhibits insulin secretion (shifts metabolism from the absorptive to the postabsorptive state)
- elevated blood AA stimulate insulin secretion
- SNS decreases insulin secretion
- inadequate insulin action produces DM resulting in hyperglycemia
- STUDY FIGURE |
|
|
Term
|
Definition
- opposes the actions of insulin
- secretion increases during the postabsorptive state (increases when blood glucose concentration is too low)
- insulin and glucagon work as a team to control blood concentration of glucose and fatty acids |
|
|
Term
|
Definition
- increase blood glucose
- GH
- cortisol
- epinephrine
- glucagon |
|
|
Term
| how does glucagon oppose the actions of insulin |
|
Definition
- promotes glycogenolysis and stimulates gluconeogenesis
- promotes fat breakdown
- promotes protein breakdown in the liver |
|
|
Term
|
Definition
- endocrine system controlled
- plasma Ca2+ must be tightly controlled
- homeostasis
- balance |
|
|
Term
|
Definition
- neuromuscular excitability
- excitation-coupling in cardiac and smooth muscle
- stimulus-secretion coupling (exocytosis)
- maintenance of tight junctions bt cells
- blood clotting |
|
|
Term
|
Definition
| - involves immediate (short term) adjustments to control Ca2+ in the blood |
|
|
Term
|
Definition
| - involves long term alow adjustments to maintain the total amt. of Ca2+ in the body |
|
|
Term
| parathyroid hormone (PTH) |
|
Definition
- secreted by parathyroid gands loaced at back of thyroid gland
- raises level of Ca2+ ions in the blood
- signals the bones, kidneys, and intestine resulting in increased plasma Ca2+
- lowers phosphate ions in the blood |
|
|
Term
|
Definition
- bones consistenly undergo remodeling which keeps skeleton at max effectiveness and helps maintain plasma Ca2+ level
- results from an interplay of bone deposition and bone resorption
- in adults, rates of deposition and resorption are about equal
- deposition of Ca2+ increases the mechanical strength of bones
- too much bone resorption can weaken bones
- osteoporosis is a reduction in bone mass
- bones are living tissues |
|
|
Term
| relationship bt PTH and Ca2+ |
|
Definition
- overall effect of PTH is to release Ca2+ ions from bones into blood
- PTH quickly releasess Ca2+ from labile pool in bone fluid (immediate need)
- stimulates the transfer of Ca2+ across the osteocytic-osteoblastic bone membranes in bones
- Ca2+ in this area is quickly replaced from mineralized bone
- PTH also promot |
|
|
Term
| relationship bt PTH and Ca2+ |
|
Definition
- overall effect of PTH is to release Ca2+ ions from bones into blood
- PTH quickly releasess Ca2+ from labile pool in bone fluid (immediate need)
- stimulates the transfer of Ca2+ across the osteocytic-osteoblastic bone membranes in bones
- Ca2+ in this area is quickly replaced from mineralized bone
- PTH also promot |
|
|
Term
| relationship bt PTH and Ca2+ |
|
Definition
- overall effect of PTH is to release Ca2+ ions from bones into blood
- PTH quickly releasess Ca2+ from labile pool in bone fluid (immediate need)
- stimulates the transfer of Ca2+ across the osteocytic-osteoblastic bone membranes in bones
- Ca2+ in this area is quickly replaced from mineralized bone
- PTH also promotes the slow transfer of Ca2+ and phosphate from a stable pool of minerals in the bones (chronic need) via localized dissolution of Ca2+ in bones into the surround ECF
- STUDY FIGURE |
|
|
Term
|
Definition
PTH signals kidneys to conserve Ca2+ and eliminate phosphate
- this effect adds Ca2+ to blood
- inverse relationship bt Ca2+ and phosphate levels in blood bc they are in equilibrium w/bone cyrstals
- product of their two concentrations must be constant |
|
|
Term
|
Definition
- indirectly promotes intestinal absorption of Ca2+ and phosphate by playing a role in vitamin D activation
- in turn, vitamin D increases intestinl Ca2+ absorption |
|
|
Term
|
Definition
- plasma concentration of Ca2+
- PTH secretion rises in response to a decrease in Ca2+ in the blood |
|
|
Term
|
Definition
- thyroid gland
- lowers Ca2+ levels in the blood but is not important in norm. control of Ca2+ metabolism
- it does protect against hypercalcemia |
|
|
Term
| control of phosphate metabolism |
|
Definition
| - controlled by the same mechanisms that regulate Ca2+ metabolism |
|
|
Term
|
Definition
- hyperparathyroidism
- can cause hypercalcemia and hypophophatemia (increase Ca2+ and decreased phosphate)
- reduces the excitability of muscle and nervous tissue because change in [ion]
- cardiac disturbance can occur
- thinning of bone
- development of kidney stones |
|
|
Term
|
Definition
| - can cause hypocalcemia and hyperphophatemia- increases neuromuscular excitibility |
|
|
Term
|
Definition
- decreases intestinal absorption of can cause hypercalcemia and hypophophatemia
- can lead to rickets (bones not a strong as should be) in kids and osteomalacia (softening of bones) in adults |
|
|
Term
|
Definition
- lack of insulin
- high [blood glucose]
- break down of fat and muscle in order to get energy supply that lacks due to decreased [blood glucose]
- 10-20% of all DM are type 1 |
|
|
Term
|
Definition
- autoimmune destruction of pancreatic beta cells
- autoantibodies
- type 1A - immune mediated; genetic predisposition; HLA markers; no genes identified yet
- type 1B - idiopathic disease; strong genetic pattern; no autoimmunity present |
|
|
Term
|
Definition
- associated with obesity and increased age
- not associated with HLA markers or autoantibodies
- free fatty acids - increase insulin secretion from pancreas initially but later it decreases
- hepatic stimulation of glucose production
- STUDY SLIDE! |
|
|
Term
|
Definition
- not really a type of DM but still related
- insulin resistance similar to type 2
- high [plasma triglycerides]
- low [plasma HDL]
- hypertension
- systemic inflammation; c-reactive protein/other mediators detected
- abnormal fibrinolysis
- abnormal fx of vascular endothelium
- macrovascular disease; coronary artery, cerebrovascular, peripheral artery disease |
|
|
Term
|
Definition
- glucose intolerance during pregnancy
- females who have GDM have increased risk to develop DM2 later in life |
|
|
Term
|
Definition
- family history of DM
- still births and spontaneous abortions leads to GDM in later pregnancies
- previous large or heavy-for-date baby
- obesity
- increased age
- more than 5 pregnancies |
|
|
Term
|
Definition
- close observation of mother and fetus
- nutrition - necssary nutrients resulting normoglycemia |
|
|
Term
|
Definition
- sudden
- polyuria
- polydipsia
- polyphagia
- blurred vision: hyperosmolar fluids in lens
- weight loss despite eat |
|
|
Term
|
Definition
- sudden
- polyuria
- polydipsia
- polyphagia
- blurred vision: hyperosmolar fluids in lens
- weight loss despite eat (occurs when it is uncontrolled with no Tx) |
|
|
Term
|
Definition
- slow
- polyuria
- polydipsia
- blurred vision: hyperosmolar fluids in lens
- obesity in the upper body |
|
|
Term
| sites of action for biguanides |
|
Definition
- DM2
- major effect is decreased hepatic glucose output due to a breakdown of glycogen
- minor effect is an increase of peripheral glucose uptake
- STUDY FIGURE |
|
|
Term
| sites of action for thiazolidinediones |
|
Definition
- DM2
- TZD's
- major effect is an increase in periphereal glucose uptake
- minor effect is decrease hepatic glucose output due to a breakdown of glycogen |
|
|
Term
|
Definition
- osmotic diuresis due to glucose
- excess urination |
|
|
Term
|
Definition
- dehydration from diuresis
- freq. drinking |
|
|
Term
|
Definition
- due to cell starvation
- eat a lot |
|
|
Term
|
Definition
- fasting glucose > 126mg/dl; not eating for 8 hrs.
- random glucose > 200mg/dL
- glucose tolerance test > 200 mg/dL; common in pregnant female in order to test for GDM; tested at intervals after given drink with high glucose levels
- A1C (glycated/glycosylated Hb) > 8%; how much glucose is incorporated into the Hb over time (high inc. = high risk for DM or have DM if >8%; norm. is bt 4-6%) |
|
|
Term
|
Definition
- dependent upon type of DM
- goal is to prevent long-term complications
- diet
- exercise
- insulin always req. for DM1; may be req'd for DM2 depending on how well it is regulated
- oral antidiabetic agents |
|
|
Term
| sites of action for alpha glucosidase inhibitors |
|
Definition
- oral hypoglycemic agents
- DM2
- target decreased glucose absorption |
|
|
Term
| sites of action for alpha glucosidase inhibitors |
|
Definition
- oral hypoglycemic agents
- DM2
- target decreased glucose absorption |
|
|
Term
| site of action for sulfanilureas |
|
Definition
- beta cell stimulators
- DM2
- increase insulin secretion
- only effective when residual beta cell fx in pancreas |
|
|
Term
| acute complications of DM |
|
Definition
- ketoacidosis (DM1)
- hyperosmolar hyperglycemic state (DM2)
- hypoglycemia (DM1 and DM2) |
|
|
Term
|
Definition
- lack of insulin
- cells break down triglycerides to form FFA and glycerol
- FFA metabolism forms ketones (ketones are acidic)
- often precipitated by infection, non-use of insulin, or OH
- have metabolic derangements |
|
|
Term
| types of metabolic derangements in ketoacidosis |
|
Definition
- hyperglycemia
- ketosis
- metabolic acidosis |
|
|
Term
| hyperglycemia in ketoacidosis |
|
Definition
- 250-1000 mg/dL (REALLY HIGH)
- osmotic diuresis
- dehydration
- electrolyte disturbances
- vomiting
- fatigue
- hypotension
- tachycardia
- hypovolemic shock |
|
|
Term
|
Definition
- ketones in the blood
- fruity breath
- fatty acid metabolism |
|
|
Term
| metabolic acidosis in ketoacidosis |
|
Definition
- contributed by ketones and AA utilized
- low pH
- low bicarbonate (bicarbonate is a regulator)
- hyperkalemia
- kussmaul breathing |
|
|
Term
| Tx for metabolic derangements of ketoacidosis |
|
Definition
| - fluid and electrolyte replacement |
|
|
Term
|
Definition
| - exhale small puffs of breath in attempt to decrease pH by blowing off CO2 |
|
|
Term
| hyperosmolar hyperglycemic state of DM |
|
Definition
- plasma osmolarity high (> 310 mOsm/L)
- blood glucose high (> 600mg/dL)
- usually result of insulin resistance in the periphery and increased carb intake and decreased fluid intake
- hyperosmolarity draws fluid from ICF to ECF (tissues lose fluid, including brain)
- often occurs in elderly b/c loss of thirst response |
|
|
Term
| Sxs of hyperosmolar hyperglycemic state |
|
Definition
- severe dehydration (thrombus formation)
- neurologic: lethargy, decreased mental capacity, coma, seizures, muscle fasciculations (twitching/squirming of muscles due to change in [ion]) |
|
|
Term
| Tx of hyperosmolar hyperglycemimc state |
|
Definition
- rehydration with caution (threat of cerebral edema)
- replacement of potassium |
|
|
Term
|
Definition
- "insulin rxn."
- rapid onset resulting from too much insulin (dosing error - DM1), low food intake, stress, exercise, OH and overuse of oral hypoglycemics (DM2) |
|
|
Term
|
Definition
- neurological: HA, difficulty problem solving, altered behavior, slurred speech, coma
- activation of ANS: hunger (parasympathetic initially), then anxiety, tachycardia, sweating, constriction of skin vessels (sympathetic) |
|
|
Term
|
Definition
|
|
Term
| counterregulatory mechanisms of DM |
|
Definition
- somogyi effect
- dawn effect |
|
|
Term
|
Definition
- cycle of insulin-induced posthypoglycemic episodes
- "hypoglycemia induces hyperglycemia" (CYCLE)
- results from increased levels of catecholamines, glucagon, cortisol, GH (counterregulatory hormones) |
|
|
Term
|
Definition
- increased levels of fasting glucose or insulin requirements, or boh bt 5-9am
- still unknown whether it is a change in normal circadian rhythm for glucose tolerance |
|
|
Term
| chronic complications of DM |
|
Definition
- diabetic nephropathy (kidney disease)
- diabetic retinopathy (retinal disfx)
- diabetic peripheral neuropathies (change in neuron fx in peripherals)
- macrovascular disorders (CHD, stroke, peripheral vascular disease)
- foot ulcers
- infections (bc no blood needed in certain areas therefore no WBCs) |
|
|
Term
| preventions for chronic complications of DM |
|
Definition
- tight control of blood glucose levels
- maintenance of normal lipid levels
- control of HTN |
|
|
Term
| 3 pathophysiologic theories of chronic complications of DM |
|
Definition
- polyol pathway
- glycoprotein formation
- tissue oxygentaion |
|
|
Term
|
Definition
| - sorbitol formation and cellular swelling |
|
|
Term
|
Definition
| - high blood glucose: eye, kidney, vasculature |
|
|
Term
|
Definition
|
|
