Endocrine System Notes PDF

The Endocrine System Comparison to the Nervous System: Nervous system - Speed - Takes less time, but also last shorter Endocrine system - Process - Takes longer to have. An effect, but it may last a longer period Hormones: Chemical that elicits a response, travels through the blood stream (railway)...

The Endocrine System Comparison to the Nervous System: Nervous system - Speed - Takes less time, but also last shorter Endocrine system - Process - Takes longer to have. An effect, but it may last a longer period Hormones: Chemical that elicits a response, travels through the blood stream (railway) - The key Targets: the place the hormone has an effect on - To have a target you must have a receptor Receptors: Target organs have where hormones fit - The keyhole Functions of the Endocrine System: 1. Regulate metabolism (building up and breaking of chemical in the body) 2. Maintain H2O balance (If there is too much it gets rid of it and vice versa) 3. Maintain electrolyte balance 4. Reproduction 5. Growth and Development Types of Stimulations: 1. Humoral (humor = blood) o Triggered by blood levels o ex. Pancreas with the production of insulin 2. Hormonal o Done by hormones telling hormones to produce more o ex. Testis to produce testosterone in males, and in females to produce more eggs 3. Neural o Nerve tells gland to produce hormone o Ex. Adrenalin hormone (flight or fight) How hormones travel through the blood: Free Hormones - Hydrophilic (water lover) Able to freely associate with water Travel freely through water-based plasma of blood Bound Hormones - Hydrophobic (not a fan of water) Complex binding protein in plasma Two main classes of hormones: 1. Amino acid based o Free hormones o Use a 2nd messenger 2. Steroid based o Bound hormones o Direct gene activation Mechanism of Action: - Hormones act in one of two ways, depending on their chemical nature and receptor location o Water-soluble hormones (all amino acid-based hormones except thyroid hormone) § Act on plasma membrane receptors § Act via G protein second messengers § Cannot enter cell o Lipid-soluble hormones (steroid and thyroid hormones) § Act on intracellular receptors that directly activate genes § Can enter cell Hormone Functions 1. Mitosis 2. Alter plasma membrane permeability 3. Secretion 4. Enzyme function 5. Synthesis of materials (make) Runs on Negative feedback: regulates hormone levels to maintain balance. When hormone levels deviate, the system acts to bring them back to normal, ensuring optimal functioning. Hypothalamus + Pituitary gland Anatomy: - Hypothalamus - Infundibulum - Anterior pituitary o Aka adenohypophysis - Posterior pituitary o Aka neurohypophysis Hypothalamus/ Posterior pituitary: - Hormones are made in the Hypothalamus, but stored/released in the Posterior pituitary - 2 Hormones o Oxytocin § The pleasure hormone § Targets: Mammary glands to release milk Uterus to contract § Works on a positive feed back Meaning It amplifies changes rather than reversing them o ADH § Antidiuretic hormone § Target: Kidneys to keep H2O § Condition: Hyposecretion Diabetes Insipidus o Due to tumor press in on a hypothalamus/ pituitary, and prevents ADH from being released o Causes: having to go the bathroom a lot and constantly drinking water Hypothalamic hormones that target Anterior Pituitary - GHRH (Growth Hormone Releasing Hormone) o Targets: Anterior Pituitary § To produce: GH (growth hormone) Targets: o Bones + Muscles to undergo mitosis - TRH (Thyrotropin Releasing Hormone) o Targets: Anterior Pituitary § To produce: TSH (Thyroid-stimulation Hormone) Targets: o the Thyroid to make more hormones - CRH (Corticotropin Releasing Hormone) o Targets: Anterior Pituitary § To produce: ACTH (Adrenocorticotropic hormone) Targets: o Adrenal Cortex to produce cortex’s hormones - GnRH (Gonadotropin Releasing Hormone) o Targets: Anterior Pituitary § To produce: FSH (Follicle Stimulating Hormone) Targets: Ovaries to mature the eggs Targets: Testes to make sperm § To produce: LH (Luteinizing hormone) Targets: Ovaries à Ovulation = kick that egg out of the ovaries Targets: Testes à produce testosterone = steroid hormone o Works on negative feedback o Steroids (testosterone) can decrease the production of sperm and sometimes make them sterile (unable to have kids) - PRH (Prolactin Releasing Hormone) o Targets: Anterior Pituitary § To produce: Prolactin (PRL) Targets: Mammary glands to produce MILK o This works on positive feedback (once it starts it will not stop!) o For it to stop women would have to go through pain The Thyroid Anatomy of the Thyroid Gland: Microscopically, composed of multiple spheres (thyroid follicles) Colloid - protein rich, gelatinous material; contains precursor for thyroid hormone and high concentration of iodine atoms, both important to thyroid hormone synthesis Parafollicular cells - in spaces between near thyroid follicles; large cells that produce calcitonin Regulation of Thyroid Hormone Secretion: (starts at hypothalamus) - TRH (Thyrotropin Releasing Hormone) o Targets: Anterior Pituitary § To produce: TSH (Thyroid-stimulation Hormone) Targets: o the Thyroid to make Thyroid Hormones (TH) § T3 and T4 T3 (Triiodothyronine): form that has two tyrosines with THREE bound iodine atoms T4 (Thyroxine): major form that consists of two tyrosines molecules with FOUR bound iodine atoms Body’s major metabolic hormone Both are iodine -containing amine hormones Effect: Almost every cell contains thyroid hormone receptors; makes effects widespread o Regulation of metabolic rate and thermoregulation- set basal metabolic rate (amount of energy required by body at rest) § Increases ATP consumption Thyroid disorders: Hyperthyroidism o Thyroid is working to much = a ton of T4 is being produced o Symptoms: § Wight loss § Feel warm due to metabolic (working faster) § Jittery § Hairy (mitosis is working more) § Goiter = enlarged gland § Exophthalmic Bug eyes = eyes bulging out o Examples: § Graves disease Autoimmune disease o Your antibodies have the same shape as TSH, Antibodies mimic TSH § Causes T4 to be produced = T4 Levels will be high § TRH levels would be low § TSH levels would be low Because if T4 is at a normal rage it won’t cause the other to rise Hypothyroidism o Thyroid that is under active (metabolic is not working very slow) o Symptoms: § Weight gain § Feel cold § Hair loss § Mentally sluggish § Thick dry skin o Examples: § Hashimoto Autoimmune disease can’t produce T3 and T4 Antibodies attack follicles cells TSH and TRH levels will be high § Iodine Deficiency Not enough production of iodine o Can produce T3 and T4 but it would not be functional, because there is no iodine § Myxedema widespread swelling, thickening, and water retention in the connective tissues, leading to facial puffiness, hoarseness, and other symptoms associated with a slowed metabolism. § Congenial Hypothyroid is a condition present at birth where the thyroid gland fails to produce sufficient thyroid hormones, potentially leading to developmental issues and cognitive impairments if not promptly treated with thyroid hormone replacement therapy. Thyroid / Parathyroids Anatomy of the Thyroid Gland: Microscopically, composed of multiple spheres (thyroid follicles) Colloid - protein rich, gelatinous material; contains precursor for thyroid hormone and high concentration of iodine atoms, both important to thyroid hormone synthesis Parafollicular cells - in spaces between near thyroid follicles; large cells that produce calcitonin Calcitonin: Under a Humoral stimulation levels are to high o Blood levels of Ca+ Production of Calcitonin by the Parafollicular cells is caused by high amounts of Ca+ in the blood. Job: is to take excess Ca+ from the blood and put into your bones to build bones (Trying to lower the level of Ca+ in the blood) Goal is to remove Ca+ from the blood this can happen in 2 ways: o 1) Surprising osteoclast activity, allowing for osteoblast are going to take Ca+ to build bone o 2) Target kidneys to execrate Ca+ > - Parathyroid Glands: Under a Humoral stimulation o Blood levels of Ca+ levels Parathyroid Hormone (PTH) Increase blood Ca+ levels, trigged by low Ca+ in the blood o Stimulate osteoclast to breakdown bone to get Ca+ o Kidneys will retain Ca+ from leaving as well > - are to low Adrenal Glands Cortex = outside of the organ Cortex: (all homerooms are steroid hormones ) Zona Glomerulosa o Produce mineralocorticoid Zona Fasciculata o Secrete glucocorticoids Zona Reticularis o Secrete gonadocorticoids (androgenic steroids) Mineralocorticoid: Aldosterone o Target kidneys à to retain Na+ (we also kick out some K+ ) § Indirectly water is going to want to follow § Results in increased blood volume and blood pressure o Stimulates K+ elimination by kidneys Glucocorticoids: Cortisol (STRESS hormone) o Inhibit inflammation by decreasing release of inflammatory chemicals o Depress immune system o Cortisol causes increase in blood levels of glucose, fatty acids, and amino acids o Prime metabolic effect is gluconeogenesis, formation of glucose from fats and proteins § Encourages cells to use fatty acids for fuel so glucose is “saved” for brain Hypersecretion of Cortisol o Cushing’s syndrome (medical induced) Moon Face (rounding of the face) Weight gain , usually fatty deposits § Induced to repress immunity, to not reject an organ Gonadocorticoids: Weak androgens (male sex hormones) converted to testosterone in tissue cells, some to estrogen May contribute to: o Onset of puberty and appearance of secondary sex characteristics o Sex drive in women o Source of estrogens in postmenopausal women Summary: Hormone Stimulus Inhibitor(s) for of Release Release Target Tissue(s) Aldosterone (Mineralocorticoid) ACTH Increased blood pressure Tubules of the kidneys Cortisol (Glucocorticoids) ACTH Increased level of cortisol Liver and muscle Effects Androgens (Androgenic steroids) ACTH Poorly understood ACTH comes from the anterior pituitary Multiple target tissues, including: Organs of the reproductive tract Brain Bone Skeletal muscle Increases sodium ion retention directly and water retention indirectly Increases potassium ion loss in the urine Increases gluconeogenesis in the liver Increases protein breakdown in muscle Increases lipolysis in adipose tissue Inhibits the inflammatory response Can be converted to testosterone in the circulation Likely responsible for development of female pubic hair and libido Adrenal Gland (Medulla) Medulla = inner piece Medulla: (amino acid based) Catecholamines Epinephrine (80%) and Norepinephrine (20%) Effects: o Vasoconstriction of blood vessels (increase blood pressure) o Increased heart rate o Increased blood glucose levels o Blood diverted to brain, heart, and skeletal muscle Both hormones have basically the same effects, but: o Epinephrine is more a stimulator of metabolic activates § ex. Bronchial dilation, and blood flow to skeletal muscles and heart o Norepinephrine has more of an influence on peripheral vasoconstriction and blood pressure Response to stressors is brief, unlike adrenal cortical hormones Pancreas Pancreas Has both exocrine and endocrine cells Acinar cells (exocrine) produce enzyme-rich juice for digestion Islets of Langerhans contain endocrine cells o Alpha (α) cells produce glucagon A way to remember is Gabi o Beta (β) cells produce insulin g = glucagon, a = Alpha (together) b= Beta, and i = insulin (together) Glucagon: Triggered by decreased blood glucose levels or sympathetic nervous system o Low blood glucose levels Raises blood glucose levels by targeting liver to: o Break down glycogen into glucose § Glucagon à glycogen à glucose o Release glucose into blood Insulin: Secreted when blood glucose levels increase Insulin lowers blood glucose o Enhances membrane transport of glucose into fat and muscle cells o glucose to form glycogen § glycogen is stored in skeletal muscles o Convert glucose to fat (particularly in adipose tissue) Diabetes Mellitus: Type 1 o (Hyposecretion of insulin) o The least prevalent o Autoimmune disorders (10%) antibodies destroy the beta cells o Treatment is to take insulin o Causes: genetic component / external component (viruses) Type 2 o (Hypoactivity of insulin ) o Receptor issue, meaning that you are unable to bring insulin into the cell o Treatment: diet and exercise 3 cardinal symptoms o Polyuria- Having to go to the bathroom a lot o Polydipsia- drinking a lot of water o Polyphagia- going to be hungry / eat like crazy § But they will lose weight because they are not in taking the glucose Pineal + Thymus Pineal: Small gland hanging from roof of third ventricle o Secrete melatonin o Affect: Day/night cycles Thymus: Large in infants and children; shrinks with age o Thymopoietins: Matures T cells Gonads Ovaries: Ovaries produce estrogen and progesterone o Progesterone § Prepares the body for pregnancy o Estrogen § Maturation of reproductive organs § Appearance of secondary sexual characteristics What comes after birth: o Hair in certainly spots o Development of breast o Fat deposits in some areas Testes Produce testosterone o Initiates maturation of male reproductive organs o Causes appearance of male secondary sexual characteristics and sex drive § What comes after birth: Hair in certainly spots Adams apple o Increased Muscle Mass o Stimulate Bone Growth o Increased RBC (red blood cells) o Necessary for normal sperm production Pineal + Thymus Pineal: Small gland hanging from roof of third ventricle o Secrete melatonin o Affect: Day/night cycles Thymus: Large in infants and children; shrinks with age o Thymopoietins: Matures T cells Gonads Ovaries: Ovaries produce estrogen and progesterone o Progesterone § Prepares the body for pregnancy o Estrogen § Maturation of reproductive organs § Appearance of secondary sexual characteristics What comes after birth: o Hair in certainly spots o Development of breast o Fat deposits in some areas Testes Produce testosterone o Initiates maturation of male reproductive organs o Causes appearance of male secondary sexual characteristics and sex drive § What comes after birth: Hair in certainly spots Adams apple o Increased Muscle Mass o Stimulate Bone Growth o Increased RBC (red blood cells) o Necessary for normal sperm production