Endocrine Flashcards
Function of Endocrine System
Differentiate reproductive and CNS in developing fetus
Stimulate sequential growth and development during childhood and adolescence
Coordinate male and female reproductive systems
Maintain optimal internal environment throughout life (homeostasis)
Initiate the corrective and adaptive responses when emergency demands occur
Hormones
Secreted into blood stream from endocrine glands
Initiate or regulate activity of organ or group of cells in another part of body
Characteristics of Hormones
Specific rates and patterns of secretion
Operate in feedback system
Affect only target cells with specific receptors
Excreted by kidneys or deactivated by liver
Hormones vs. Neurotransmitters
Both must bind to a receptor to send signal
Neurotransmitters localized
Hormones widespread
Hormones slower and longer lasting
Proteins + Peptides
Hormones mad from chains of amino acids
Water-soluble
On cell surface, cannot enter cell membrane
Circulate in free unbound forms
Short half life
Steroids
From cholesterol
Lipid soluble
Action within cell
Transported by carrier or binding proteins
Last in blood for hours to days
Amines
Simple molecules, act like proteins/peptides or steroids, derived from tyrosine
Hormone Release
Response to altered cellular environment or in maintenance of regulated level of hormone or other substance
Negative feedback
Endocrine regulation
Neural control
Hormone Transport
Throughout blood and by lymphatic system
Target Cell Receptor Functions
Recognize and bind specifically to particular hormone
Initiate signal to appropriate intracellular effectors
Direct Effect Action
Changes in cell function specifically from stimulation by a particular hormone
Permissive Effect Action
Less obvious changes that facilitate maximal response or function of a cell
Hormone cannot exert full effects without presence of another hormone
Synergistic or antagonistic effects
Hormone Removal
Concentration returns to normal follow target action.
Enzyme-catalyzed reactions to inactivate a hormone
Excreted by kidney
Deactivated by liver
Hypothalamus
Links nervous system to endocrine system
Function of Hypothalamus
Maintain homeostasis
Control hormones
Hypothalamic Homeostasis
Exerts control on ANS
Receives information from internal environment, operates on the environment by projecting onto the medulla
Hypothalamic Control
HR and BP
Temp, sweating
Fluid and electrolyte balance, thirst
Digestion, appetite, body weight
Glandular secretion of stomach and intestines
Production of substances influencing pituitary gland
Sleep cycle
Hypothalamic Hormones Anterior Pituitary
Corticotropin releasing hormone
Dopamine
Gondatropin releasing hormone
Growth releasing hormone
Melatonin
Somatostatin
Thyrotropin-releasing hormone
Hypothalamic Hormones Posterior Pituitary
Oxytocin
Vasopressin
Corticotropin Releasing Hormone
Combines with vasopressin to stimulate AP to secrete ACTH
Dopamine
Inhibits secretion of prolactin from AP
Gondatropin-releasing hormone
Stimulates AP to secrete LH and FSH
Growth releasing hormone
Stimulates AP to secrete growth hormone
Melatonin
Influences sleep pattern and immune system
Somatostain
Inhibits secretion of growth hormone for the AP
Thyrotropin releasing hormone
Stimulates AP to secrete TSH
Oxytocin
Influences uterus and milk ejection in pregnant/lactating women
Vasopressin
Influences water reabsorption
Hypothalamic Dysfunction
Depression
Hyperactivity
Sleep disorders
Hormone dysfunction
Immune system disorders
Autonomic system dysfunction
Abnormal responses to stress
Temp regulation problems
Pituitary Gland
Functionally linked to hypothalamus
Affects almost every body function
Anterior Pituitary Regulation
Secretion of hypothalamic peptide hormones or releasing factor
Feedback effects of hormones secreted by target cells
Direct effects of mediating neurotransmitters
Adrenocorticotropic Hormone
Stimulates cortex of adrenal gland to produce glucocorticoids, mineralocorticoids and sex hormones
Thyroid Stimulating Hormone
Stimulates thyroid gland to produce thyroid hormones
Also effects CNS, cardiovascular, calcium metabolism
Prolactin
Proliferation and secretion of mammary glands
Follicle Stimulating Hormone
Stimulates growth and maturation of ovarian follicles
Regulates menstruation or spermatogenesis
Luteinizing Hormone
Regulates reproduction
Ovulation, formation of corpus lute or spermatogenesis and secretion of sex hormones
Growth Hormone
Somatotropin
Promotes growth
Increased GH Stimulation
1 hour after sleep
Hypoglycemia
Exercise
Puberty
GH Regulation
Negative feedback loop via somatostatin to tell hypothalamus to stop producing GH
Pituitary Adenoma
Benign tumour classified based on size
Hypersecretion of pituitary hormones
Effect of Pituitary Adenoma
Gigantism and acromegaly from too much GH
Cushing’s disease from ACTH
Hyperthyroidism from TSH
Pituitary apoplexy
Cushing’s Syndrome
Hormonal disorder from prolonged exposure to high levels of cortisol
S/Sx of Cushing’s Syndrome
Upper body obesity, round face, increased fat around the neck, and thinning arms and legs
Women have excess hair growth on faces, necks, chest, abdomens, and thighs, menstrual periods irregular or stop
Men have decreased fertility with decreased sex drive
Fatigue, weak muscles, HTN, high BS, irritable, anxious, depressed
Posterior Pituitary
Hormones packaged in neurons of hypothalamus and travel to posterior pituitary
Released from depolarization
Vasopressin
Increased water reabsorption and more concentrated urine
Increased secretion in response to increased plasma osmolality
Increases of ADH secretion
Decreased intravascular volume
Stress, trauma, pain, exercise, nausea, nicotine, exposure to heat + drugs
Vasoconstrictor at high doses
Decreases of ADH secretion
Plasma osmolality, increased intravascular volume, HTN, alcohol ingestion
Oxytocin
Women: contractions of uterus and milk ejection
Men: sperm motility, prostate
Syndrome of Inappropriate Secretion of ADH
Small cell lung carcinoma
Hyponatremia and inappropriately concentrated urine
Management of SIADH
Water restriction
Seizure treatment with 3% saline
Na replacement slow
Thyroid Gland
Located in neck below larynx
Produces hormones that control rate of metabolic processes throughout body
Thyroid Hormones
Thyroxine (T4)
Triiodothyronine (T3)
Role of Thyroid Hormones
Increases rate of protein, fat, glucose metabolism, results in increased body temp
Works with parathyroid hormone to regulate calcium levels
Promotes GI tract, cardiovascular, reproductive and temp functions
Increases sensitivity to sympathetic stimulation
Promotes growth and development
CNS function and development
Hypothyroidism Causes
Congenital defects, autoimmune disorders (hashimoto’s disease, sarcoidosis)
Iodine deficiency
Medications (amio, lithium)
Abnormal growth/tumours (thyroid/pituitary)
Neuro + hypothyroidism
Confusion, syncope, lethargy
Pulmonary + hypothyroidism
Dyspnea, hypoventilation + CO2 retention from changes in respiratory muscles
Reproductive + hypothyroidism
Decrease hormones causing an ovulation, oligospermia
Endocrine + Hypothyroidism
Increased prolactin
Hematological + Hypothyroidism
Decrease red cell mass, iron, and folate absorption
Cardiovascular + hypothyroidism
Decrease SV, HR, CO, increase PVR, cold intolerance, enlarged heart
ECG Changes + Hypothyroidism
Bradycardia
Prolonged PR
Depressed P waves
Flattened or inverted T waves
Low amplitude QRS
Renal + Hypothyroidism
Decrease blood flow and GF causing increased water retention + hyponatremia
GI + Hypothyroidism
Decrease appetite, weight gain, fluid retention, decrease metabolism, glucose absorption, increased insulin sensitivity
MSK + Hypothyroidism
Muscle aching + stiffness, decrease bone formation, increase bone density, aching + stiff joints
Integumentary + Hypothyroidism
Dry, flaky, brittle head and body hair, reduced growth of hair + nails, slow wound healing, cool skin
Myxedema
Sign of severe + long standing hypothyroidism
Altered composition of dermis and tissues from hyaluronic acid
Diseases causing hyperthyroidism
Graves disease
Adenoma/Plummer’s Disease
Thyroiditis
Thyroid cancer
Endocrine + hyperthyroidism
Enlarged thyroid gland, increased cortisol degradation, hypercalcemia, decreased insulin sensitivity
Reproductive + Hyperthyroidism
Impotence, amenorrhea
GI + Hyperthyroidism
Weight loss, peristalsis, n/v, anorexia, abdominal pain, increase use of hepatic glycogen stores and adipose + protein stores
Integumentary + Hyperthyroidism
Excess sweating, heat intolerance, temporary hair loss
Sensory + Hyperthyroidism
Elevated upper eyelid, blinking, protruding eyeballs
Cardiovascular + hyperthyroidism
Increased CO, decreased PVR
Nervous + Hyperthyroidism
Restlessness, short attention span, fatigue, tremor, insomnia
Pulmonary + Hyperthyroidism
Dyspnea
S/Sx Thyroid Storm
Enhanced SNS activity
CNS effects
Cardiovascular
GI
Parathyroid Gland Function
Secrete parathyroid hormone to maintain levels of calcium in blood and ECF
PTH in Kidney
Acts on plasma receptor in proximal tubule of nephron
Increases calcium reabsorption and decreases phosphorus reabsorption
Decreases proximal tubule reabsorption of bicarb
Stimulates synthesis of vitamin D
Increases GI absorption of calcium
Adrenal Gland
Made of inner medulla and outer cortex
Role of Adrenal Gland
Regulates stress
Cholesterol needed
Adrenal Medulla
Best in relation to SNS
Innervated by preganglionic sympathetic fibers
Secretes epi and NE
Adrenal Cortex
Outer region of adrenal gland
Zones of adrenal cortex
Zone Glomerulosa
Zone Fasciculata
Zone Reticularis
Adrenal Cortex Hormones
Glucocorticoids
Mineralocorticoids
Sex Steroids
Cortisol
Main secretory hormone of adrenal cortex
Secreted by ACTH via hypothalamus and anterior pituitary gland
Cortisol + Insulin
Decreases glucose uptake and increases synthesis in liver
provides amino acids for glucose production in liver
Promote lipolysis and increased blood cholesterol levels
Aldosterone
Most potent mineralocorticoid
Maintains salt + water balance and promotes K excretion
Stimulates RAAS
Androgens
Primarily dehydroepiandosterone
Precursos to sex hormones
Pheochromocytoma
Tumors of adrenal gland which produce excessive catecholamines
Secrete excess epi and NE
Can be life threatening due to adrenal crisis
Glucagon + Pheochromocytoma
Stimulates adenylate cyclase to produce increase cAMP, promotes hepatic glycolysis + gluconeogenesis, resulting in rise in BG
Effect of glucagon on heart resembles catecholamines
Dopamine + Pheochromocytoma
Sympathomimetic agent
Cushing’s Disease
Tumor in pituitary gland stimulating excess release of cortisol from adrenal gland through large amounts of ACTH
Cushing’s Syndrome
Too much cortisol in blood stream (regardless of cause)
Addison’s Disease
Chronic adrenal insufficiency
Production of insufficient glucocorticoids and mineralocorticoids
S/Sx of Adrenal Crisis
Severe vomiting + diarrhea
Fever
Tachycardia
Hypotension
Altered LOC
Hypoglycemia
Seizures
Sudden penetration pain in the legs
Lower back or abdomen pain
Pancreas
Endocrine + exocrine gland
Endocrine Pancreas
Islets of Langerhans
Glucagon
Produced by alpha cells and cells lining GI tract
Release inhibited by high glucose and increased by low glucose
Stimulated by alanine, glycine, and asparagines
Acts in liver through glycogenolysis and gluconeogenesis
Antagonistic to insulin
Glucagone Secretion
Hypoglycemia
Amino acids
Acetylcholine
NE
Epinephrine
Inhibition of Secretion
Fatty acids
Somatostatin
Insulin
Insulin
Produced by beta cells
Promotes glucose uptake from blood to cells
Synthesis of proteins, carbs, lipids, nucleic acids
Intracellular transport of K
Promotes glucose storage
Enhances glycolysis
Promotes lipogenesis and inhibits lipolysis
Regulating Insulin
Chemical, hormonal, and neural control
Somatostatin
GHIH
Produced by Delta cells
Essential in carb, fat and protein metabolism
Regulates alpha cell and beta cell function by regulating secretions of insulin, glucagon, and pancreatic polypeptide
Type I Diabetes
Inability of beta cells to produce insulin
Destruction of pancreatic beta cells
Type 2 Diabetes
Impaired ability of tissues to respond to insulin
Normal or higher amounts of insulin in circulation
DKA Patho
Cells cant use glucose
Free fatty acids metabolized
Osmotic diuresis
High anion gap, vasodilation, Kussmauls
HHS
Poorly controlled type 2 diabetes
Decreased utilization of glucose from insulin resistance
Osmotic diuresis with glycosuria and volume depletion
No kussmauls resps
HHS vs DKA
HHS different with greater degree of hyperglycemias, lesser degree of acidosis, absent/minimal serum + urine ketones
Glucagon uses
Hypoglycaemia
Beta blocker toxicity
Anaphylaxis with refractory hypotension
CCB toxicity refractory to IV calcium
Relief of lower esophageal foreign body
