Diploma Prep Endocrine System PDF

Nervous and Endocrine System Breakdown Nervous System (~10 marks) Endocrine System (~6-7 marks) 5 marks, 1NR - Glands & hormones (2) - Neuron (2) - Specific hormone functions - Impulse (1) (2) - Synaptic transmission (2) -...

Nervous and Endocrine System Breakdown Nervous System (~10 marks) Endocrine System (~6-7 marks) 5 marks, 1NR - Glands & hormones (2) - Neuron (2) - Specific hormone functions - Impulse (1) (2) - Synaptic transmission (2) - Negative feedback loops (ie 5 marks, 1NR TSH, ACTH) (1) - Brain (2) - What if (1) - Eye & Ear (2-3) - Disorder (1) Endocrine System  Outline the roles of the endocrine Hormones that affect growth and metabolism system vs. the nervous system (hGH, thyroxine, TSH, calcitonin, PTH) Describe examples of positive vs. Hormones that affect the body’s response to negative feedback stress (epinephrine & norepinephrine, cortisol, Identify the principal glands of the ACTH) endocrine system Hormones that affect blood sugar (insulin and (hypothalamus/pituitary complex, glucagon) Hormones that affect water and ion balance thyroid, parathyroid, adrenal glands, (ADH and aldosterone) and islet cells of the pancreas) and Physiological consequences of hormone describe what they are responsible for imbalance, including diabetes mellitus (hypo vs. Compare water soluble vs. fat soluble hypersecretion) hormones * Ensure that you understand where each hormone is produced, what tissues/organs it targets, its overall effect on the body, and how it is regulated through negative feedback.  Nervous System vs. Endocrine System Nervous System Endocrine System Mode of Action Neuron Bloodstream Signal Electrochemical impulses (action Chemical messengers (hormones) potential & neurotransmitters) Form of Cell to cell (ie. neuron to neuron or Hormones travel through blood to communication neuron to effector cell) target cells Speed of response Fast Slow Length of response short-term long-lasting Endocrine system: responds to internal changes via feedback loops Positive feedback: - Increases the stimulus that sets off the response - Generally moves body away from homeostasis - Eg. oxytocin release during parturition Endocrine system: responds to internal changes via feedback loops Negative feedback: - Inhibits the stimulus that sets off the response - Generally returns the body to homeostasis - Eg. regulation of estrogen, progesterone and testosterone Key glands of the endocrine system Each gland secretes specific hormones that will target specific tissues resulting in different physiological effects Hypothalamus & Pituitary Gland - Hypothalamus regulates the pituitary gland - Release tropic hormones (stimulate other glands to release hormones) - Pituitary = “master gland” - Releases hormones involved in growth, development, metabolism and reproduction  Pituitary hormones - Posterior pituitary: releases hormones produced by the hypothalamus - Oxytocin and ADH - Anterior pituitary: releases hormones it has synthesized - hGH, prolactin, TSH, ACTH, FSH and LH Adrenal Gland - Adrenal medulla (inner layer) - Epinephrine and norepinephrine → short-term stress response - Adrenal cortex (outer layer) - Glucocorticoids (eg. cortisol) and mineralocorticoids (eg. aldosterone) → long-term stress response Pancreas - Secretes digestive enzymes into small intestine - Islets of Langerhans = specialized pancreatic cells secreting hormones to regulate glucose retention - Alpha cells secrete glucagon - Beta cells secrete insulin Water Soluble & Fat Soluble ○ Water soluble hormones (proteins, peptides, and amino acid derivatives) cannot cross the lipid membrane, and thus interact with cells by binding to external receptor sites (e.g. hGH, epinephrine) ○ Fat soluble hormones (steroids) are able to diffuse across the lipid membrane, and thus interact with cells by binding to receptor sites within the cytoplasm (e.g. sex hormones) Hormone Responses: 1. Growth and metabolism (hGH, TSH, thyroxine, calcitonin and PTH) 2. Stress (epinephrine, norepinephrine, cortisol, ACTH, aldosterone) 3. Blood glucose balance (glucagon, insulin) 4. Water and ion balance (ADH)  Textbook: pg. 444 - 450 Notes: pg. 25 - 27 Hormones: Growth & Metabolism  Human Growth Hormone (hGH) - Secreted by anterior pituitary gland - Targets almost all body tissues - Increases protein synthesis, cell division, and metabolic release of fat from adipose tissue Pituitary Dwarfism - Promotes growth of cartilage, bone and muscle tissue - Important in childhood development Gigantism  Thyroxine (T4) - Secreted by thyroid gland - Targets almost all body tissues - Increases metabolism of fats, proteins and carbohydrates - High T4 = hyperthyroidism - symptoms? - Low T4 = hypothyroidism - symptoms? T4 controlled via negative feedback by TSH Thyroid requires iodine to produce thyroxine - Lack of iodine in diet = inhibits thyroxine production - No thyroxine = no signal to stop TSH release - Constant stimulation of thyroid gland by TSH results in goitre formation Calcitonin - Secreted by thyroid gland - ↑ [Ca2+] in blood = calcitonin stimulates uptake of calcium from blood into bones - Lowers blood Ca2+ levels Parathyroid Hormone - Secreted by parathyroid gland - ↓ [Ca2+] in blood = PTH released 1. bones break down into calcium phosphate (Ca2+ released into blood) 2. kidneys reabsorb Ca2+ from filtrate 3. vitamin D activated which stimulates increased Ca2+ reabsorption in intestines - Increases blood Ca2+ levels Calcitonin and PTH work antagonistically to regulate blood [Ca2+]  Textbook: pgs. 451 - 455 Notes: pg. 30-31 Hormones: Stress Response Stress hormones are secreted by the adrenal glands  Epinephrine and Norepinephrine - Secreted by the adrenal medulla - Regulates short-term stress response - “Fight or flight” - Stimulated by nerve impulse from the hypothalamus (rapid response) - Tiggers increased breathing rate, heart rate and blood flow to heart and muscles. Glucose released into the bloodstream  Cortisol (glucocorticoid) - Secreted by adrenal cortex - Regulated by ACTH* (released by anterior pituitary) - Regulates long-term stress response - Increases blood glucose levels - Promotes muscle breakdown into amino acids (amino acids go to liver to make glucose) - Promotes breakdown of fat cells *ACTH = adrenocorticotropic hormone  Aldosterone (mineralocorticoid) - Secreted by adrenal cortex - Regulates long term stress response - Increased O2 and nutrient delivery to cells - Increased sodium absorption in nephrons (kidneys) - Increased solute in blood = more water reabsorbed = increased blood pressure  Textbook pgs: 456 - 462 Hormones: Blood Sugar, Water & Ion Balance  Hormones affecting blood sugar: Insulin & Glucagon - Insulin and glucagon are secreted by cells in the pancreas Insulin: lowers [glucose] in blood - Secreted by beta cells of the islets of Langerhans in the pancreas - Targets: - Skeletal muscle and adipose tissue: increases permeability to glucose - Liver cells: increases permeability to glucose, glucose is stored as glycogen Glucagon: increases [glucose] in blood - Secreted by alpha cells of the islets of Langerhans in the pancreas - Targets: - Liver cells: glycogen breaks down into glucose and is released into the bloodstream - Adipose (fatty) tissue: breaks down into glucose and is released into the bloodstream Insulin & glucagon work antagonistically to maintain blood glucose levels Diabetes mellitus: inability to produce enough insulin or respond appropriately to insulin Type 1 - Diagnosed in childhood - Immune system attacks beta cells of pancreases - Decreased insulin production - Treatment: daily insulin injections Diabetes mellitus: inability to produce enough insulin or respond appropriately to insulin Type 2 - Develops over time - Cell receptors stop responding to insulin or beta cells produce less insulin - Treatment if cells unresponsive to insulin: diet, exercise, thiazolidinediones - Treatment if insulin production is low: insulin injections before meals, sulfonylureas Antidiuretic hormone (ADH): regulates water & ion balance - Secreted by posterior pituitary gland when blood osmotic pressure is high (↓ [water]) - Target: nephrons in kidneys - Regulates water reabsorption by making nephrons tubules more permeable to water (concentrated urine) - Decreased osmotic pressure in blood (↑ [water]) = negative feedback loop to hypothalamus inhibits ADH Diabetes Insipidus: inability to produce, store or properly respond to ADH - Patients produce large volumes of urine (loss of ions from blood) - Risk of dehydration - Can occur during pregnancy (some components of placenta break down ADH) - Treated by administering ADH Likely Disorder Questions on Diploma Diabetes (Mellitus type I, Mellitus type II, Insipidus) Growth (Too much or too little hGH → gigantism or drwarfism) Thyroxine (too much → high metabolism (Grave’s disease) or too little → low metabolism (goiter)) 1928 1143  Review: Endocrine Glands Stress Hormones Blood Glucose Hormones Growth & Metabolism Hormones