Endocrine System Flashcards
Endocrine system
Regulates bodily function & maintains homeostasis through network of organs that communicate directives to various tissues
Eustress
Positive, desirable form of stress; increased: neural efficiency, vascular compliance, O2 extraction, cardiac function, musculoskeletal integrity & function
Distress
Negative form of stress; increased: platelet adhesion, cortisol production, LDL & triglycerides, susceptibility to inflammation, loss of protein sparing
Role of hormones
Released by endocrine glands to direct actions of other tissues via chemical messenger
Steroid hormones
Cholesterol based compounds impact sexual development, reproduction, tissue synthesis, inflammation, metabolism (cortisol, estrogen, testosterone)
Polypeptide hormones
Chains of amino acids synthesized within endocrine cells, activate secondary messengers (insulin, glucagon)
Pituitary Gland
Releases growth hormone
Thyroid
Releases thyroxine
Adrenal Cortex
Releases aldosterone, cortisol
Growth Hormone Action
Stimulates IGF, protein synthesis, growth & metabolism
Thyroxine Action
Stimulates metabolic rate, regulates cell growth & activity
Aldosterone Action
Promotes sodium, potassium metabolism & water retention
Cortisol Action
Promotes use of fatty acids and protein catabolism, conserves sugar, maintains blood glucose
Adrenal Medulla
Releases epinephrine, norepinephrine
Epinephrine action
Increases cardiac output, increases glycogen catabolism and fatty acid release
Norepinephrine action
Properties of epinephrine, constricts blood vessels
Pancreas
Releases insulin, glucagon
Insulin action
Promotes cellular glucose uptake, stores glycogen, aids in protein synthesis
Glucagon action
Releases sugar from liver into blood circulation
Liver
Releases insulin like growth factors
IGF action
Increases protein synthesis
Ovaries
Release estrogen
Estrogen action
Stimulates bone remodeling activity; female sex hormone
Testes
Release testosterone
Testosterone action
Stimulates growth, increases protein anabolism, reduces body fat; male sex hormone
Anabolic hormones
Compounds involved in tissue growth and protein synthesis
Growth hormone
Promotes cell division by facilitating protein synthesis; mobilizes lipids for fuel, protecting glycogen stores
IGF1
Central signalling hormone for muscle growth following resistance training
Testosterone
Anabolic hormone in men and woman; stimulates male secondary sex characteristics in men and acts on gene expression of protein synthesis; men have 10x women
Estrogen
Steroid hormone integral to bone health in men and women; promotes secondary sex characteristics in women; men convert to estradiol
Carbohydrates are metabolized into glucose to
Regulate blood sugar levels
Pancreas has two main functions
Produce digestive enzymes to break down macronutrients for absorption in lining of small intestine; regulate blood sugar levels through release of insulin and glucagon
Hyperglycemia
Abnormally high blood glucose levels; can damage bodily tissues including vascular structures (diabetes)
Hypoglycemia
Abnormally low blood glucose levels; metabolic demands of brain and CNS can’t be met
Glucagon
Stimulates glycogen breakdown in liver to increase blood glucose levels
Insulin
Pulls blood glucose into tissue; dysfunction associated with insulin resistance and diabetes
Thyroid
Primary regulator of growth and metabolism rate; acts via T3 & T4
Hypothyroidism
Low thyroid activity; results in weight gain, can retard growth & mental development
Catecholamines
Potent neurotransmitters that help the body respond to stress or elicit fight/flight response (dopamine, epinephrine, norepinephrine)
Cortisol
Released in response to exercise stress and low glucose levels; chronic elevation associated with overtraining
Fight or flight response
Acute increase in adrenal activity; enhanced CO, blood flow, energy metabolism in response to perceived threat
Adrenal glands are very important to managing
Exercise based stress response
Hormone response to anaerobic training
Increased: GH, T3/T4, cortisol & epinephrine (heavy only), testosterone
Decreased: Insulin
Hormone response to aerobic training
High intensity (above lactate threshold) increases GH
Testosterone suppressed in high intensity training
Higher insulin sensitivity, glucagon when prolonged
Steady catecholamines
Increased cortisol when prolonged
Does not stimulate GH-IGF pathways
