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overall function of endocrine system
- metabolism
- growth and development
- reproduction
- homeostasis
-
components
hormones- chemicals secreted by endocrine glands
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Glands
organs of endocrine system
-
endocrine glands
- ductless
- secrete chemicals(hormones) into intracellular space
- diffuse into blood-- target cells/tissues
-
exocrine glands
- secrete substances into ducts that empty onto surfaces or into cavities
- sudoriferous
- eccrine-sweat
- apocrine
- sebaceous
- saliva glands
-
location of endocrine glands
- cranial
- necks
- ab cavity
- medistinum
-
mechanisms of hormone action-- protein hormones
- non steroid hormones
- 1st messenger(open lock)
- bind to receptors on the target cell membrane (lock and key) mechanism triggers
- 2nd messenger(inside cell)
- enter nucleus and acts on DNA
- changes cell's activities
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steroid hormones
- fats- fatty
- lipid soluble
- pass thru cell membrane to nucleus
- bind to receptors within the target cell
- influence cell activity by acting on DNA
- causes formation of a new protein
- aldosterone, corisol, testosterone, estrogen, progesterone, androsone
-
regulation of hormone secretion controlled by homeostatic feedback
- negative feedback
- mechanism that reverse the direction of a change
- positive feedback
- mechanism amplify physiological change
- blood clot
- child birth
-
if gland is unable to respond to feedback mechanism
- hyposecretion
- hypersecretion
-
prostaglandins
- powerful substances found in a wide cariety of body tissues
- produced in a tissue and diffuse only a short distance to act on cells in that tissue or neighboring tissue
- produced close to site of action
- effects of prostagmandins
- immune system and inflammation- vasodilation and increased capillart permeability
- relaxation of smooth muscle
- circulatory system- platlet aggregation
- GI- protect lining of GI tract
- reproductive- uterine contractions
- sensitization of nerve cells to pain
-
prostaglandin inhibitors
- anti-inflammatory agents prevent the synthesis of prostaglandins at the site of inflammation
- effect
- decrease inflammation
- decrease pain
- commin agents
- NSAIDS
- ASA
- prostaglandin analogs- induce labor
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pituitary gland- cranial cavity-location
sella turcia of sphenoid bone
-
pituitary stalk
attached to hypothalmus
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Parts of pit gland- anterior
- adenohypohysis
- structure- endocrine gland
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posterior pit gland
- neurohypophysis
- structure more closely related to nervous system.
-
anterior pit
- tropic hormones- stimulate another endocrine gland
- thyroid stimulating hormane- TSH
- stimulates growth and secretion of thyroid gland
- Adrenocorticotropic hormone
- stimulates growth of adrenal cortex
- stimulates secretion of glucocorticoids
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gonadotrophins
- stimulate the gonads
- FSH- ovarian follicle to mature
- seminiferous tubules to frow sperm
- LH-
- ovulation
- testosterone production by interstitial cells
-
Growth Hormone- functions
- accelerated protein anabolism
- accelerate fat catabolism
- slows glucose catabolism
- increase blood glucose levels
- hyperglycemia
-
abnormal functions of GH
- gigantism- hyper secretion during childhood
- dwarfism- hypo secretion during childhood
- acromegaly
- hyper secretion in adulthood
- enlargement of bones in
- hands
- feet
- jaws
- cheek
-
prolactin- lactogenic hormone
- stimulates breast development during pregnancy
- stimulates production of breast milk
- abnormal secretion- prolactinemia
- women- galactorrhea- lactation not associated with childbirth or nursing
- men-
- erectile dysfunction
- decreased libido
- cause- pit tumor
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post pit gland ADH
- stores and releases hormones produced by hypothalmus
- release of hormones caused by nervous stim
- ADH
- accelerates water reabsorption from kidney tubules nack to the blood
- decreases urine volume-- concentrates urine
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Post pit gland- oxytocin
- stimulates the pregnant uterus to contract
- responsible for let down reflex- release of milk into ducts
-
hypothalmus
- produces hormones secreted by post pit gland
- ADH
- Ocytocin
-
thyroid gland- location
below pharnyx, in front and on either side of the trachea.
-
tyroid hormones
- throxine- t4
- thriodothyronine- t3
- production require iodine
-
tyroid functions
- affect all body function that depend on energy
- affect BMR
- speed release of energy
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tyroid hormone- calcitonin
- maintains homeostasis of blood calcium levels
- prevents hypercalcemia
- tones down blood calcium
- decreases blood calcium levels
- prevents resorption of bone
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Parathytoid gland-
- works with calcitonin
- 4 of them
- hormone
- Function
- prevent hypocalcemia
- increase calcium levels
- increase resorption of bone
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Pancreas
- exocrine gland- digestive function
- endocrine gland- diffuse into blood carry into tissues
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Pancreatic islets- islets of langerhans
- Hormones and functions
- Glucagon
- alpha cells
- increas BG levels
- glycogen converted to glucose
- Insulin
- beta cells
- decrease BG levels
- facilitates passage of glucose into cells
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Ovaries
- Ovarian follicles- estrogen
- secondary sex characteristics
- Corpus luteum
- maintains pregnancy
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Testes
- semiferous tubules- produce sperm
- interstitial cells- testosterone
- secondeary sex characteristics
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Placenta- temp endocrine gland
- Hormones
- estrogen
- pregesterone
- Function
- maintains pregnancy
-
Human Gonadotropin (HCG)
- maintains corpus luteum
- estorgen
- pregesteronee- lining of uterus maintained
- produced by chorion of fetus- outer membrane of embryo
-
Thymus- t-cells
- Hormone thymosin
- immunity
- mediastinum
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Pineal gland
- roof of 3rd ventricle of the brain
- secretory activity releated to light
- received input from optic nerve
- 3rd eye
-
Melatonin
- produced by pineal gland
- regulates internal hormone
- induce sleep
- regulates onset of puberty
- inhinits ovary activity- affects menstrual cycle
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clinical implications of melatocin
- SAD
- treatment of jetlag
- fibrotic with age
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ANH
- secreted by atrial wall of heart
- stimulates sodium loss from kidneys
- decrease BP
- antagonist to aldosterone
- only hormone stimulate loss of sodium
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Adrenal Glands location
curve over tops of kidneys
-
parts of adrenal gland
- adrenal cortex- outer layer
- mineralocorticoids- salt
- glucocorticoids- sugar
- androgens- sex
- adrenal medulla- inner layer
- catchecholamines
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Layers of adrenal cortex
- zona glomerulous
- outrmost
- secretes mineralocorticoids
- zona fasciculata
- middle later
- secrets gluco
- zona reticulairis
- inner layer
- secretes androgens
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mineralocorticoids
- affects body minerals
- increase blood sodium
- decrease blood K
- affects fluid volume
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Glucocorticoids or Corticosteroids- Cortisol
- maintains BG levels
- increase blood glucose levels
- gluconeogenesis- new glucose formed from fats and proteins
- spares glucose for use by brain
- WAKE UP
- Anti-infmmatory effect
- Increase gastric acid and pepsin secretion
- Necessary for full functioning of the catecholamines and the general adaptation response
- enchance effect of
- epinephrine
- norepinephrine- vasoconstriction
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Androgens
- sex hormones
- masculinazion in males
- estorgen in women- postmenapausal
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pharmocological dose of glucocorticoids
- replacement therapy- reduce symptoms
- anti-allergy/anti-imflammatory
- respiratory disorders
- malignacies
- cerebral edema
- organ transplant
- ulcerative colitis
- eye disease
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Adverse reaction of glucocorticoids
- delayed wound healing
- increase infection
- fluid imbalance- hypokalemia, edema, hypertention
- muscle wasting
- osteoporosis
- mood changes
- cataracts, glacoma
- thrombosi
- hypercholesterolemia
- athersclerosis
- belly fat
- moon face
- buffalo hump
- trucal obesity
- increase BG- diabtetes
- adreogentic effect- beard mustache(women)
- acne
- bruising
- gastritis and peptic ulcer
- adrenocortical insuffiency
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Adrenal Cortex clinical conditions-
- cushing syndrome
- increased secretion of hormones of the adrenal cortex
- prolonged adm of high doses of corticosteroids
- hypertention, hyperglycemia, hypokalemia, immunosuppression, osteoporosis
- addison's disease
- decreased function of adrenal glands
- hypotension, hypoglycemia, hyperkalemia, intolerence to stressors.
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Corticosteroids
Glucocorticoids
pharmacological implications
- uses
- replacement therapy- physiological doses
- reduce symptoms- pharmacologic dose
- reduce imflammations and allergic responses
- malignancies
- ulcerative colitis
- eye disease
- respirtaory disorders
-
steroid withdrawal syndrome
- adrenocortical insufficiency
- supression of anterior pit gland- ACTH
- may occur 1 week after pharm dose
- suppression of acth may last up to 2 years. should be monitored 1-2 years after high dosage or long term treatment
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symptoms of steroid withdrawal syndrome
- anorexia
- nausea
- lethargy
- headache
- joint pain
- fever
- wt loss
- hypotension
- rebound of condition being treated
-
pt teaching of steroids
- take with food, milk or antacids
- total dose should be taken first thing in the AM
- nicotine raises blood levels-- avoid smoking
- alcohol enhances effect
- do not stop abruptly- taper dose as ordered
- side effects
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Adrenal Medulla
- structure-- sympathetic ganglia
- hormones- catchecholamines
- epinephrine- heart rate
- nor ephinephrine- potent vasoconstrictor
- Function
- intensify and prolong effects of sympathetic nervous system
- allows for stress response or general adaption syndrome
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general adaptation syndrome
- based on work of Hans Selye
- adaptation is the process of responding to change
- describes both the physiological and psychological responses to change
- callista roy
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Stress
- response produced by a change in the environment that is perceived as challenging, threatening, or damaging to homeostasis.
- stress occurs when the equilibrium of the body is disturbed
- non specific response
- regardless of stimulus
- response is the same
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Universal stressors- Internal- physiological stressors
- heat or cold
- microbial invasion(flu, mrsa)
- trauma/surg
- hemorrhage
-
individual stressors- psychological
- day to day problems
- major life events
- maybe be positive- wedding, bday party
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Sources of stress
- Internal
- originate within an ind
- External
- outside ind
- Developmental
- occurs at predictable times throughout life
- school, marriage, retirement
- Situational
- unpredictable
- Anticipatory
- worry
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response to sress depends on
- perception
- degree of health and fitness
- previous life experiences and personality
- social support system- culture
- personal coping mechanisms
*stimulus must be perceived as a stressor in order for stess response to be excited*
-
common pt stressors
- hospital gown
- sharing a room
- change in sleep
- excessive light/noise
- wait
- uncertainty
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sense of control over stressors help decrease stress response
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stages of sress response
- alarm
- resistance
- exhaustion
-
Alarm
- fight or flight
- sympathetic response
- local adaption
- inflammaion
-
resistance
- continuing endocrine activity allows body to adapt or compensate for stressor
- cortisol secretion is increased
- counters inflamm response
- glucose for energy
- epinephrine and norephinephrine secretion continues
- maintains fluid volume- spares sodium
- vasocontriction
- maintains BP
-
adaptation
- body compensates for stressor
- body limits stressor to a small area
- Mal-adaption
- prolonged resistance can lead to a sress related disorder
- hypertension
- infection/delayed wd healing
- stress ulcers
-
exhaustion
- prolonged exposure to stressor
- depletes body's resources
- result
- rest- the body enters a stage where the primary goal is conversation of energy in order to survive
- damage to vital body systems
- circulatory system
- immune system
- DEATH
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Adaptation VS Exhaustion
- adaptive energy resources of ind- heartyness of pt
- severity of stressor
- external adaptive resources- medical interventions
-
General Adaptation syndrome
a
activates a neuroendocrine mechanism
-
neuroendocrine mechanisms component
- CNS
- hypothalmus
- SNS
- Ant pit gland
- post pit gland
- adrenal cortex
- adrenal medulla
-
Effective stress response
- increase glucose available for energy
- increased oxy uptake
- increased excretion of carbon dioxide
- blood volume and cardiac output maintained-- BP maintained
- increased mental alertness
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Prolonged stress response
- increased BP
- decreased immunity
- increased gastic secretion- sress ulcers
- arrhythmias
- backpain
- decreaed libido
- fertility problems
- headache
- asthma
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