Endocrines Flashcards
Hypothalamic pituitary axis
Releasing hormones stimulates synthesis and secretion disorders
Inhibiting hormones prevent synthesis and secretion
Hormones released by hypothalamus acting on anterior lobe
Growth hormone releasing hormone
Growth hormone inhibitory hormone
Thyrotropin releasing hormone
Corticotropin releasing hormone
Gonadotropin releasing hormone
Prolactin inhibitory hormone
Growth hormone stimulus
Stimulus
-growth hormone releasing hormone From hypothalamus
-fasting low sugar and vigorous exercise
-grhelin secreted in stomach
Growth hormone inhibited by
Somatostatin/ growth hormone inhibitory hormone
GH inhibits GHRH
Growth hormone over the years
Peaks at teenage years, every 3 to 5 hours, highest peak, one hour after onset of sleep
Released by somatotrophs
Action of growth hormone
increases in muscle mass
decrease adipose tissue
Increase linear growth of bone
Increase cell number and cell size
Proteins synthesis and gluconeogenesis
T3 is needed for GH to work
Action of growth hormone on muscles and adipose tissue
Muscle- increase muscle mass- Decreasing glucose uptake, increase amino acid uptake, increased protein synthesis, leading to increase in muscle mass
Adipose- decrease adipose tissue- increase lipolysis, decreased glucose uptake, decreased adipose tissue
Action of growth hormone on bones
Increased linear growth
Increase collagen synthesis
Increase protein synthesis
Cell proliferation
Action of growth hormone in liver
Proteins synthesis
gluconeogenesis
Conserves carbohydrates
Growth hormone abnormalities
Hypopituitarism- pituitary defect, this function of the hypothalamus
Dwarfism- Hyposecretion in a child
Deficiency in adults-few symptoms cardiovascular disease, osteopenia, social, isolation, disturbed sexual life)
GH excess
- tumor of GH cells
- Hypopituitarism
-Gigantism, increase in GH before epiphyseal plates close
-Acromegaly, increase in GH after puberty
Acromegaly
Enlargement of cranium and lower jaw
Malocclusion teeth
Bulging forehead
Coarsening of facial features
Bulbous nose, thick lips, enlarged tongue
Enlarged hand and feet
Enlarged heart, liver and spleen
Factors that contribute proper production of thyroid hormones
Iron
Iodine
Tyrosine
Zinc
Selenium
Vitamin E, B2, B6, C, D
Factors that inhibit production of thyroid hormones
Stress
Infection, trauma, medication
Fluoride
Toxins- pesticides mercury lead
autoimmune disease
Factors that increase conversion of T4 to T3
Zinc
Selenium
Factors that improve cell sensitivity to thyroid hormones
Vit A
Zinc
Exercise
Thyroid hormone in the liver
Converts glucose to glycogen
Increase fat synthesis
Thyroid hormone in bone
Bone growth
Bone maturation
Stimulation of epiphysis.
Thyroid hormone in CNS
Infants- axonal maturation
Adults - decreased alertness, decreased velocity of conduction
Hyperthyroidism
Hypermetabolism intolerance to heat
Increased sympathetic activity
Increased heart rate
Increased stroke, volume
Increase cardiac output
Hyperdynamic circulatory state
Treatment- thyroidectomy, radioactive iodine injections
Toxic goiter
Hyperthyroidism
2 to 3 times the normal size , hyperplasia
Each cell increases the rate of secretion
Hyperthyroidism examples
Toxic goiter
Thyrotoxicosis
Graves’ disease (auto immune disorder)
Anterior pituitary adenoma (secondary)
Hypothalamic tumor (tertiary)
Hypothyroidism
Decrease metabolism intolerance to cold
Weight gain
Bradycardia, cardiac complications
Sluggishness
Etiology- iodine deficiency, infiltrative disorders
Treatment- levothyroxine
Hypothyroidism examples
Myxedema
-Total lack of thyroid hormones
-Medication to reduce the low thyroid hormone
Cretinism
Early intervention can reverse damage
Extreme hypothyroidism in fetal life
Presents after a few weeks as they adapt with maternal thyroid levels in utero
Hashimotos atrophic thyroiditis - autoimmune
Thyroid hormone stimulus
Role of temperature
Thyrotropin releasing hormone from hypothalamus
Thyroid Stimulating hormone from anterior pituitary
Thyroid hormones
Thyroxine T4
T4 converts to T3
Triiodothyronine T3
Thyroid and BMR
Increases heat production
Increases O2 consumption
Increases cardiac output
Parathyroid glands
4 located over the thyroid
One gland is adequate to maintain calcium and phosphate homeostasis
Parathyroid glands stimulus
Low blood calcium
Parathyroid gland function
Make more parathyroid hormone (PTH)
PTH causes the body to put more calcium into the blood
PTH causes the bones to release their calcium into the blood
Hyperparapthyroidism
Increases PTH
Primary hyperparapthyroidism
By neoplasm or hyperplasia
-80% by adenoma
-18% by hyperplasia
-2% by parathyroid carcinoma
Secondary hyperparapthyroidism
By chronic renal failure
-undistinguishable from primary parathyroid hyperplasia
- Hyperfunction is compensatory mechanism triggered by Hypercalcemia
Hereditary hyperparapthyroidism
Hereditary
<5%
Hypoparathyroidism
Decreased PTH
most common after surgical, exploration, or resection of thyroid gland, removal of parathyroid glands
Recover function with supplemental synthetic PTH
Rare causes - congenital, genetic or auto immune
Signs and symptoms of hypoparathyroidism
Deficiency of PTH hypocalcemia
- Neuromuscular excitability
- Muscle contraction spastic
- Hypocalcemic tetany
- Heart with arrhythmias - arrest
Adrenal gland hormone stimulus
Hypothalamus releases corticotropin, releasing hormone CRH
Stimulates anterior pituitary release of ACTH
Target cells are the adrenal glands
Adrenal gland cortex and medulla
Three layers of cortex
1 Zona glomerulosa - release mineralocorticoids (aldosterone, corticosterone)
2 Zona fasciculata- release glucocorticoids (cortisol, cortisone)
3 Zona reticularis - release androgens (estrogen, testosterone)
Medulla- Catecholamines
Glucocorticoids
Cortisol- steroid
Adrenal hormone
Glucocorticoids stimulus
Circadian rhythm, stress, hypoglycemia, trauma, broken bones, Burns, surgery, cold infection, anxiety, psychological stress
Function of glucocorticoids
Muscle- decrease glucose uptake, increased protein degradation, decreased protein synthesis
Adipose issue- increase fat mobility, decreased glucose uptake
Liver- gluconeogenesis and glycogen synthesis
Bone- decreased bone formation
Pancreas- counter interacts insulin production
Increases GFR- dilates afferent
CNS- limbic system, stress hormone
Which hormone is released in minutes during trauma?
Glucocorticoids- cortisol
Immunosuppressant effects of glucocorticoids
Suppresses the immune system
Inhibits the inflammatory response
For treating bee stings poison ivy and pollen allergies
Helps prevent rejection of transplanted organs
Exogenous administration will do what to glucocorticoids?
May shut down ACTH production and cause atrophy of adrenal cells
Mineralocorticoids
Aldosterone (steroid)
Mineralocorticoids stimulus
Renin- angiotensin and high potassium
Action of Mineralocorticoids (aldosterone)
Increased renal sodium reabsorption
Increased renal potassium secretion
Renin
Function of Mineralocorticoids aldosterone
Regulating, sodium and potassium on renal distal tubule
Controls BP
Maintains electrolyte balance
Androgens
Estrogen
Testosterone
Sexual characteristics and function
Hypercortisolism
Cushing’s syndrome- Increase secretion of ACTH from anterior pituitary (secondary aldosteronism)
Adrenal tumor secretes cortisol
Pituitary tumor that autonomously secretes ACTH
Hypercortisolism effects
Moon face
Buffalo hump
Thinning of skin
Osteoporosis
Excessive hairiness
Excessive breakdown of protein and lipid reserves
Hypertension
Impaired glucose metabolism
Striae cutis
Fatigue weakness
Hypocorticolism
Addisons disease
Hyposecretion of all adrenal steroid hormones
Too little cortisol and aldosterone
All age groups
Life-threatening
Hyperaldosteronism
Primary-overproduction at Adrina wins
Secondary - due the kidneys, overactivity of renin, which acts on the RAAS system
- Raise arterial hypertension
-Low potassium, high sodium
Symptoms of hyperaldosteronism
Hypertension, related, headaches, face flushing, hyponatremia
hypokalemia, constipation, polyuria, paralysis, cardiac disturbances
Androgenital syndome
Virilization by androgens
By inborn error of steroidal metabolism
Adulthood by tumors
Affected women present with hirsutism, loss of menstrual cycles, change of voice
Signs and symptoms of Addison’s disease
Fatigue
Weight loss, decreased appetite
Low blood pressure craving salt, low blood sugar
nausea, vomiting, diarrhea
Abdominal pain
Muscle and joint pain
Depression
Loss of body hair and sexual dysfunction
Diagnosis of Addison’s disease
Blood test ACTH stimulation
imaging tests
Treatment of Addison’s disease
Oral corticosteroids
Corticosteroid injections
ADH stimulation
Hyperosmotic plasma, Hypovolemia, hypotension, sympathetic stimulation
Angiotensin two stimulates posterior pituitary to release ADH
Action of ADH
Target tissue, the kidney
Increases water reabsorption at the kidney and thus decreasing plasma osmolarity
Hyper secretion of ADH
Water intoxication due to fluid retention
Hyponatremia
CNS dysfunction due to brain swelling
Manage- correct sodium in balance, and underlying cause
Rehabilitation implications - monitor for weight gain, and blood pressure
Hypo secretion of ADH
Diabetes insipidus- ADH insufficiency
- kidneys fail to absorb water
Large amounts of dilute urine
Polydipsia , dehydration, constipation
Management- exogenous replacement of ADH
Oxytocin stimulus
Newborn sucking breast, sight, smell, sound of an infant
Oxytocin, inhibitory stimulus
Stress and Catecholamines
Moms need to relax when pumping or nursing
Action of oxytocin
Milk let down in mammary glands
Uterine contractions in labor facilitates delivery of the baby and placenta
Catecholamines
Released from adrenal medulla, considered a big sympathetic ganglia
Epinephrine and norepinephrine
Stimulates by sympathetic nervous system
Actions of Catecholamines
Liver- increase blood glucose, glycogen, broken down to glucose
Adipose tissue
Muscle
Fight and flight response - increase in blood pressure, increasing respiratory rate, increasing metabolic rate
Tumor- pheochromocytoma can lead to hypersecretion
