metabolic and endocrine systems Flashcards
metabolic system
- governs chemical and physical changes that take place within body to enable growth and function
- catabolism: organic compounds breaking down
- anabolism: combining simple molecules for tissue growth
inherited metabolic disorders
- diagnosed in utero via amniocentesis or chorionic villus sampling
- s/s tend to include lethargy, apnea, poor feeding, tachypnea, vomiting, hypoglycemia, urine changes, seizures
- more immediate symptoms = more dangerous disorder
phenylketonuria
PKU - amino/organic acid metabolic disorder
- intellectual disability w/ behav and cog issues secondary to elevation of serum phenylalanine - excess primarily affects brain
- deficiency in enzyme ohenylalanine hydroxylase - normally converts excessive phenylalanine to tyrosine
- etiology: autosomal recessive, white people
- s/s: within few months of birth; gait disturbances, severe intellectual disability, hyperactivity, psychoses, lighter features, abnormal body odor
- treatment: dietary restriction of phenylalanine throughout lifetime can avoid all manifestations of disease
tay-sachs disease
lysosomal storage disorder
- absence of deficiency of hexosaminidase A - produces acculmulation of gangliosides (GM2) within brain
- etiology: autosomal recessive, eastern european jewish
- s/s: at 6 MO, miss developmental milestones; continue to deteriorate in motor and cog skills; die by 5 YO
- treatment: no effective treatment; rec genetic testing in high risk populations
mitochondrial disorders
- over 100 forms - each has different spectrum of disability
- etiology: genetically inherited or spont mutation in DNA -> impaired function of proteins in mitochondria
- s/s: vary depending on disorder; can include loss of muscle coordination, muscle weakness, visual and hearing problems, learning disability, heart, liver, kidney disease, GI disorders, dementia
- treatment: new diagnoses w/ varied treatment to alleviate symptoms and slow progression
wilson’s disease
hepatolenticular degeneration
- inherited disorder in eastern europeans but can be any group, appears in people < 40 YO and can be in children 4-6 YO
- etiology: autosomal recessive; defect in body’s ability to metabolize copper -> accumulates in brain, liver, cornea, kidny
- s/s: kayser-fleischer rings around iris d/t copper deposits, basal ganglia degenerative changes, hepatitis, ataxic gait; emotional/behav changes, eventual MSK deformity, pathologic fracture, osteomalacia, muscle atrophy, contractures
- treatment: pharm intervention w/ B6 and D-penicillamine to excrete excess copper; prevent hepatic failure
rehab for pts with inherited metabolic disorders
- awareness of dietary restrictions
- training to prevent deleterious effects from metabolic disease
- facilitate developmental milestones w/in pt tolerance
acid-base metabolic disorders
- metab regulated by endocrine and NS
- if acid-base balance compromised, can alter metabolic function and cause s/s
metabolic alkalosis
- increase in bicarbonate accumulation or loss of acids
- pH > 7.45
- etiology: after continuous vomitting, antacid ingestion, diuretic therapy; associated with hypokalemia or nasogastric suctioning
- s/s: nausea, diarrhea, prolonged vomiting, confusion, muscle fasciculations, muscle cramp, hyperexcitability, convulsions; if untreated, comatose, seizures, resp paralysis
- treatment: manage underlying cause, correct electrolyte imbalance, KCl administration
metabolic acidosis
- accumulation of acids due to acid gain or bicarb loss
- pH < 7.35
- etiology: renal failure, lactic acidosis, starvation, diabetic or alcoholic ketoacidosis, diarrhea, toxins
- s/s: compensatory hyperventilation, vomiting, diarrhea, HA, malaise, hyperkalemia, cardiac arrhythmias; untreated can cause coma and death
- treatment: treat cause, correct imabalnce, administer sodium bicarb
rehab considerations for pts with acid-base disorders
- recognize high risk populations - renal, CV, pulm disease; burns, fever, sepsis; mech vent; DM; vomiting, diarrhea, enteric drainage
- recognize signs of dehydration in a diabetic pt
- injury prevention during involuntary muscle contractions secondary to metabolic alkalosis
- pts w/ diuretic therapy may be at risk for potassium depletion
- trousseau’s sign during blood pressure - indicates calcium deficiency and early stages of tetany
metabolic bone disease
- disruption in normal metab w/ skeletal system that houses calcium and phosphorus to continuously balance remodeling of cortical and trabecular bone to optimize structure of skeleton
- disruption of homeostasis - result in deformity, bone loss, frature, softening of bone, arthritis, pain
osteomalacia
- metabolic condition where bones are soft secondary to calcium or phosphorous deficiency - adequat bone matrix but insufficient calcification in matrix d/t deficiency
- etiology: calcium lost d/t inadequate intestinal absorption and phosphorus lost d/t increase in renal excretion; can also be due to vit D deficiency
- s/s: aching, fatigue, weight loss; myopathy and sensory polyneuropathy w/ periarticular tenderness and pain, thoracic kyphosis deformity; bowing of LEs; struggle with trans and standing
- treatment: underlying etiology, increased nutrition, pharm intervention w/ vit D or phosphate supplements
osteoporosis
- decrease in bone mass - increases risk of fracture; primarily affects trabecular and cortical bone where rate of bone resorption accelerates while rate of bone formation declines
- declining osteoblast function coupled with loss of calcium and phosphate salts will cause bones to becomes brittle
- etiology: primary - idiopathic, postmenopausal, involutional (senile); secondary - result of another primary conditoin or with meds
- s/s: compression and other spine fractures, low thoracic or lumbar pain, loss of lumbar lordosis, kyphosis, dowager’s hump
- treatment: vitamin and pharmacological intervention, nutrition, assistive and adaptive devices, some surgical intervention
paget’s disease
- metabolic condition with heightened osteoclast activity - bone formation lacks true structural integrity
- bone appears enlarged but lacks strength d/t high turnover secondary to abnormal osteoclast proliferation
- etiology: genetic and geographical incidence, most common > 50 YO
- s/s: MSK pain w/ bony deformities; common with skull, clavicle, pelvis, femur, spine, and tibia; pain, HA, vertigo, hearing loss, mental deterioration, fatigue, increased cardiac output, HF
- treatment: pharmacological intervention using biphosphates to inhibit bone resporption and improve quality of involved bone; exercise, weight control, cardiac fitness
rehab considerations for pts with metabolic bone disease
- awareness of signs of compression fracture
- resistance training and endurance training to build bone density and increase strength
- avoid treatments that exacerbate condition or placae pts at risk for fracture
medical conditions that may cause low bone mass
- cushing’s syndrome
- osteomalacia
- hyperthyroidism
- hyperparathyroidism
- celiac
- RA
- renal failiure
- hypogonadism
- osteogenesis imperfecta
osteopenia
- low bone mass not severe enough to qualify as osteoporosis
- may not have actual bone loss but naturally lower bone density than established norms
- t-score > -2.5 SD
osteopetrosis
- conditions characterized by impaired osteoclast function causing bone to become thickened but fragile
- inherited condition
- s/s vary widely
bone mineral density
- t-score: how many SDs above or below average young healthy adult norms in BMD is
- z-score: how many SDs above/below age and gender adjusted norms BMD is
- non-modifiable risk factors: age, early menopause, h/o fx, slender build, family history, female, Asian or white, sometimes glucotcorticoids
- modifiable: vitamin D and calcium intake, estrogen deficiency, smoking, drinking, caffeine, sedentary
- interventions for children/adolescents: nutrition, regular physical activity, avoid smoking/drinking
- interventions for adults: nutrition - vit D and calcium, regular WB exercises, avoid smoking and drinking, postural education and fall prevention
osteoporosis
- t-score -2.5 SD or lower
- severe is -2.5 SD or lower w/ one or more related fractures
endocrine system
- endocrine glands (specialized, ductless) secrete hormones in bloodstrem to travel to signal specific target cells throughout body
- work with NS to regulate metabolism, response to stress, sexual reproduction, BP, water and salt balance
endocrine system vs NS
- endocrine system
- secreting cells send hormones through blood to signal specific target cells
- hormones diffuse into blood, travel long distances to virtually every area of body
- endocrine effectors consist of virtually all tissues
- regularoty effects slow and long lasting
- nervous system
- neurons secrete NTs to signal nearby cells that have appropriate receptor site
- NTs sent short distances across synapse
- nervous effectors limited to muscle and glandular tissue
- regulatory effects appear rapidly and are often short lived
hypothalamus
- part of diencephalon below thalamus and cortex
- connects to pituitary gland through infundibular or pituitary stalk
- responsible for regulation of ANS - body temp, appetite, sweating, thirst, sexual behavior, rage, fear, BP, sleep
- affects other endocrine glands through impact on pituitary
pituitary gland
- normally pea sized, located at base of brain just beneath hypothalamus
- two parts: adenohypophysis (anterior) and neurohypophysis (posteroir)
- considered most important part of endocrine system d/t it releasing hormones that regulate other endocrine glands
- “master gland” influenced by seasonal changes and emotional stress
- secretes endorphins that act on NS and reduce senstivity to pain
- controls ovulation, works as catalyst for testes and ovaries to create sex hormones
thyroid gland
- on anterior and lateral surfaces of trachea immediately below larynx, shaped like bow tie or butterfly w/ 2 lobes (R and L) joined by an isthmus
- produces thyroxine and triiodothronine - control rate at which cells burn fuel from food
- increased thyroid hormones = increased rate of chemical reactions in body
parathyroid glands
- 4 found on post surface of thyroid’s lateral lobes
- produce paraythyroid hormone - antagonist to calcitonin, important for maintenance of normal blood levels of calcium and phosphate
- PTH increases reabsorption of calcium and phosphate from bones to blood
- PTH secretion stimulated by hypocalcemia and inhibited by hypercalcemia
- normal calcium levels impacts neuromuscular excitability, normal clotting, and cell membrane permeability
adrenal glands
- 2 adrenals on top of each kidney - out portion is adrenal cortex and inner is adrenal medulla, each secrete different hormones
- adrenal cortex: corticosteroids that regulate water and sodium balance, body’s response to stress, immune system, sexual development and function, metabolism
- adrenal medulla: epinephrine that increases HR and BP w/ stress
pancreas
- in upper L quadrant of abdomen from duodenum to spleen
- has exocrine and endocrine tissues
- islets of langerhans: cells that produce hormones in pancreas
- alpha cells - glucagon
- beta cells - insulin
- [above] work in combo to ensure consistent level of glucose in bloodstrem and maintenance of energy stores within body
ovaries
- provide estrogen and progesterone - contribute to regulation of menstrual cycle and pregnancy
- estrogen secreted by ovarian follicles - develop and maintain female sex characteristics (breast development, cycles)
- progesterone produced by corpus luteum - maintains lining of uterus at level necessary for pregnancy
testes
- in scrotum btw upper thughs
- secrete androgens (including testosterone) - regulate changes associated with sexual development and support production of sperm
steroid hormones
prostaglandins
- all cells create prostaglandins from phospholipids of cell membrane
- unique as they do not circulate in blood - instead exert effects only where they are produced
- capable of variety of effects - related to inflammation, pain mechanisms, vasodilation, vasoconstriction, nutrient metabolism, blood clotting
amine hormones
catecholamines
- include epinephrine, norepinephrine, dopamine - synthesized from chromaffin cells within adrenal medulla
- SMS stimulation releases catecholamines into blood stream
- epi has one of largest effects on SNS - produces fight of flight response, targets CV and metabolic systems
- catecholamines also increase cardiac contraction, blood vessel constriction, activate glycogen breakdown, block insulin secretion, increase metabolic rate, dilation of airways in lungs
peptide hormones
insulin
- insulin secreted by beta cells of islets of langerhans within pancreas
- released when there is elevation in blood glucose - insulin produces increase in cellular uptake of glucose for metabolism
- insulin stimulates skeletal muscle and liver to store glucose and increase amino acid transport across hepatic, muscle, and adipose tissues
- insulin release affects all body systems w/ primary goal to reduce blood glucose levels
growth hormone-releasing hormone
- released by: hypothalamus
- target: pituitary gland
- function: increases release of GH
- regulation of secretion: CNS feedback, circulating levels of hormones
growth hormone-inhibiting hormone
- released by: hypothalamus
- target: pituitary gland
- function: decreases release of GH
- regulation of secretion: CNS feedback, circulating levels of hormones
gonadotropin-releasing hormone
- released by: hypothalamus
- target: pituitary gland
- function: increases release of luteinizing hormone and follicle-stimulating hormone
- regulation of secretion: CNS feedback, circulating levels of hormones
thyrotropin-releasing hormone
- released by: hypothalamus
- target: pituitary gland
- function: increases release thyroid-stimulating hormone
- regulation of secretion: CNS feedback, circulating levels of hormones
corticotropin-releasing hormone
- released by: hypothalamus
- target: pituitary gland
- function: increases release of adrenocorticotropic hormone
- regulation of secretion: CNS feedback, circulating levels of hormones
prolactin-releasing hormone
- released by: hypothalamus
- target: pituitary gland
- function: stimulates release of prolactin
- regulation of secretion: CNS feedback, circulating levels of hormones