Homeostasis PDF

HOMEOSTASIS 🏳️‍🌈 Maintaining Balance Homeostasis: maintenance of a steady internal state, despite changes in external environment Examples: Blood pressure, body temperature, blood glucose and ph, fluid balance Maintaining Homeostasis - Balance is obtained by mainta...

HOMEOSTASIS 🏳️‍🌈 Maintaining Balance Homeostasis: maintenance of a steady internal state, despite changes in external environment Examples: Blood pressure, body temperature, blood glucose and ph, fluid balance Maintaining Homeostasis - Balance is obtained by maintaining a dynamic equilibrium Made possible by 3 functional components: 1. Receptor or sensor: receives the stimulus or information 2. Control centre or coordinating centre: puts the information together (integrates) and determines (coordinates) the sequence of events follow 3. Effector or regulator: performs a response Feedback system - A cycle of events in which a variable (body temp, blood glucose, blood ph, etc) is continually monitored, assessed and adjusted. - Uses a sensor; a control centre and an effector Types of feedback systems: 1. Negative feedback - Process by which a mechanism is activated to restore conditions to their original state. 2. Positive feedback: - Process by which a small effect is amplified (moves the controlled variable even further from a steady state) - Reinforces the change - Ex. Womens contractions during birth giving (pressure on cervix, more hormones means more contractions and pressure on cervix) Thermoregulation Thermoregulation: the maintenance of body temperature within a range that enables cells to function efficiently Ectotherms: - Organisms that depend on air temperature to regulate metabolic rates - Body temperature is often regulated through sun exposure - Ex. Invertebrates, fish, amphibians, reptiles Endotherms: - Organisms that are able to maintain a constant body temperature regardless of their surroundings (within reason) - Regulation can occur through adjusting respiration rate, vasoconstriction and vasodilation, sweating, adjusting heart rate, shivering) - Ex. mammals and birds Core temperature - Core temperature: the temperature of internal body including organs such as the liver, heart, blood Human temperature: Core temperature Peripheral temperature Most constant fluctuates Between 36.5 and 37.5 Can be 4 C lower than 37 C on cold days Chest cavity, abdominal cavity Fingers, toes Heat and cold stress - The body is constantly exposed to heat stress & cold stress - Ex, Exercise, environmental temperature Regulating temperature - The hypothalamus is the key to regulation! - Gland in the vertebrate brain that coordinates nerve and hormone function Response to extreme cold 1. Hypothermia - Core temperature drops below normal range  - Can result in coma or death - Body responds by diverting heat from the periphery to the core 2. Metabolism of brown fat - Brown fat: dark adipose tissue with many blood vessels involved in the production of heat in hibernating animals and human babies - Converts chemical energy to heat - Studies show it is present in some capacity in adults; stimulated by cold Water Balance RECALL: osmosis: the movement of water from an area of high water concentration to an area of low water concentration Osmotic pressure: pressure that results from the difference in water concentration between two sides of a selectively permeable membrane - The greater the water gradient, the greater the osmotic pressure Hyperosmotic - A solution with higher solute concentration (less water), on one side of the membrane - Water moves towards the hyperosmotic side Hypoosmotic - A solution with lower solute concentration (more water), one one side of the membrane - Water moves from the hyperosmotic side Isosmotic - A solution with the same solute and water concentration - Water moves across the membrane when the two solutions have different water concentrations - Movement continues until they are isosmotic (no net movement) Osmoregulation & excretion - To ensure chemical and structural ability of body cells, the ECFd must be isosmotic with the intracellular fluids of cells  - Cells regulate ionic and pH balance and osmotic balance to maintain homeostasis - Certain ions and toxic compounds (metabolites of nitrogenous compounds must be eliminated) Excrecion - The elimination of waste products and foreign matter from the body - Maintains ionic and osmotic equilibrium - Involves excretory urinary system The kidney - The kidneys play a crucial role in - Eliminating wastes - Balancing blood pH - Maintaining water balance Importance of excreting waste - The cells of the body obtain energy by converting complex compounds into simpler ones, BUT… Many of these compounds can actually be harmful! Proteins - Protein is used to maintain tissue and promote cell growth - When excess protein is present, they are converted into carbohydrates (but proteins contain nitrogen - amino group) DEAMINATION: - Remove of an amino group from an organic compound - Occurs in the liver - Byproduct is ammonia (water-soluble gas) = extremely toxic The human excretory system (urinary system) - Is made up of the kidneys, ureters, bladder and urethra Renal arteries: branch from aorta, carries blood Kidneys - Weighs 170g, size of a fist, bean shaped, reddish brown colour  - Located on either side of the vertebral column, just below the diaphragm, protected by the lower rib cage, surrounded by protective fat - Hold much as 25% of the bodies blood at any given time - Filters waste from blood - Helps maintain H2O balance If cut Longitudinally- 3 major parts: - Cortex: outer region, somewhat granular appearance - Medulla: arranged in a group of pyramid shaped regions - Pelvis: innermost part, hollow chamber where urine collects before entering ureter - Average adult loses 2L of h20/day through urine, prespriation, exhaled air, volume increases as physical activity increases - Maininging h20 balance- humans c=must consume 2L of water per day - A drop of: - 1% causes thirst - 5% brings about extreme pain and collapse - 10% causes death Ureter: - Extend from each kidney and conducts urine from kidneys to bladder - Wall contains fibres of smooth muscle, contractions aid the movement of urine out the kidney - 25 cm long - Cells secrete mucus which lines the lumen walls and protects cells from the urine Urinary bladder - Stores urine until it is released - Hollow elastic-walled organ in the urinary systems of some fishes, most amphibians, some reptiles, and all mammals DID YOU KNOW? - When: - 200ML urine collected - Bladder stretches slightly & signal sent to the brain - ~400mL urine collected - More stretch receptors activated & message becomes more urgent - ~600mL urine collected - Voluntary control is lost, urinary sphincter relaxes, urine is expelled - Internal Sphincter - Ring of muscle at base of bladder under involuntary control - External sphincter - Ring of muscle under voluntary control - Urethra - Single tube that leads out of bladder - ~6mm in diameter - In males this tube also carries semen - Urine - Amber colored fluid made by the kidneys from the blood - It contains excess water, salts, proteins and waste products in the form of urea and some acid - Normal 1.5L passed every 24h - Intake of diuretic substances such as alcohol for caffeine increases urine productions (these substances inhibit secretion of antidiuretic hormone (AD), therefore less h20 reabsorbed) - Urination - When bladder is full - Stretch receptors in bladder wall activated - Stretch receptors in bladder wall activated - Nerve impulses sent to spinal cord - Results in urge to urinate - When opportunity arises, brain signals external sphincter causing it to relax - Smooth muscles in walls of bladder contract, urine expelled - Emptying under involuntary control - Relaxing of the external sphincter is under voluntary control (voluntary control must be learned through potty training) The nephron and urine formation The nephron - Tiny functional unit of the kidney that filters wastes from the blood - There are over a million nephrons in each kidney - Each nephron has its own blood Blood Flow - The pathway that blood flows from the heart to the kidney and back to the heart again 1. Aorta 2. Renal arteries - Connection to aorta ensures that kidneys have a large volume of high pressure blood necessary for filtrations 3. Afferent arterioles - Small branches from the renal artery - Supply the nephrons with blood 4. Glomerulus - Afferent arterioles branch further into a capillary bed called the glomerulus - Filtration of blood 5. Efferent arterioles - Carry blood away from the glomerulus 6. Peritubular capillaries - Enter peritubular capillaries (networks of small blood vessels that wrap around the nephron, reabsorbing solutes from, the nephron into the blood, secretes solutes from the blood back to the nephron) 7. Venules 8. Renal vein 9. Vena cava Parts of the nephron - Bowman's capsule - 1st part of the nephron where blood is initially filter - Small folded structure that encircles a group of capillaries (the glomerulus) in cortex - Has selectively permeable membrane Glomerulus: - A network of high pressure capillary bed enclosed by the bowman's capsule Parts of the nephron Proximal convoluted tubule (PCT) - Folded structure connected to the bowman's capsule where selective reabsorption occurs Loop of Henle: - A selectively permeable loop that descends into the medulla and establishes a salt gradient Distal convoluted tubule (DCT): - Folded structure connected to the loop of Henle where further selective reabsorption occurs Collecting ducts: - Several DCTS enter the collecting duct - Transports urine down the medulla to renal pelvis The formation of urine 3 steps: 1. Filtration: - Occurs as body fluids move from the blood into Bowman’s capsule 2. Reabsorption - Transfers essential solutes and water from the nephron back into the blood 3. Secretion - Transfers material from the blood back into the nephron Filtration - Starts at the bowman’s capsule: - The selectively permeable membrane admits water, glucose, amino acids, salts, some drugs, vitamins and urea - The higher pressure of the glomerulus drives fluid (water and solutes) from capillaries and into the capsule - Fluid is now called filtrate - Blood cells, platelets and plasma proteins are too large to pass through membrane and therefore stay in the capillaries Reabsorption - Filtrate enters into the proximal convoluted tubule (PCT) (most reabsorbed here) from the bowman's capsule - Water, ions and nutrients are transferred back into the ECF via passive and active transport. Urea and other unwanted compounds are not reabsorbed - When nutrients leave the nephron, a hypertonic solution is created and therefore, water will flow from the nephron to the ECG - Movement of water is also further facilitated by aquaporins - Nutrients and water now enter the peritubular capillaries - Reabsorption occurs until a threshold level is reached (max. Amount of materials that can cross nephron) - Selective reabsorption – only molecules recognized by carries molecules are actively transported Reabsorption CONT. - From PCT the filtrate continues to the loop of Henle: - Loop of Henle generates a high concentration of solutes in the cells and fluid of the medulla - Descending limb is.. - Permeable to water but impermeable to salt - Therefore, solute concentration in filtrate increases as loop descendants - Ascending limb is… - Permeable to salt but impermeable to water - In the lower region, NaCl is passive transport into ECF - In the upper region, NaCl is actively transport into the ECF - Therefore, solute concentration in filtrate decreases as loop ascends - Water cannot follow (impermeable) therefore, there is an increased salt concentration outside the tubule (within the medulla) - From the loop of Henle, the filtrate enters the distal convoluted tubule (DCT) - DCT - involved in fine tuning water balance  - Selective reabsorption of nutrients from the nephron into blood by active transport - More ions and solutes move out of the tubule than into it - Increases transportation of water out of the nephron - From the DCT, the filtrate enters the collecting ducts: - Collecting duct – functions as a conservation device - Further removal of water through ducts because it flows back down through the medulla and the concentration gradient set up by the loop of Henle - Now called urine - Reabsorbs NaCl by active transport - Urea is passively reabsorbed to aid in the concentration gradient set up in the medulla Secretion - Removal of waste products from the blood into the nephron - Wastes are secreted at several points in the nephron - PCT, DCT, collecting ducts - Examples include: - H+ ions are actively secreted (helps to balance acidity – coupled with HCO3- reabsorption) - K+ ions - Detoxified points (from liver) - Products of drugs - Small amounts of ammonia (from deamination) Pathway of urine: - Collecting ducts → renal pelvis → ureters → urinary bladder → exits body through the urethra ****** Urine output and water balance Water balance - Increased water intake = increased urine output - And vise versa - Increase exercise= increased water loss (through cell resp)  - There are special osmoreceptors in the hypothalamus that monitor the osmotic pressure of blood - (blood volume) - Cells in the walls of the distal tubules and collecting ducts will have receptors for two hormones: ADH and Aldosterone, affecting the permeability Conservation of water - Hypothalamus triggers secretion of ADH, making the walls of the nephron more permeable to water, increasing reabsorption of water - This makes urine more concentrated Elimination of water - When the body must lose excess water, ADH secretion is inhibited - The walls of nephron become impermeable to water, decreasing the reabsorption - This makes urine diluted Salt balance - If salt level is low, aldosterone from the adrenal gland is released - Aldosterone travels in the blood to the kidneys (ascending limb of the loop of Henle and the collecting duct) - Water follows sodium out of the tubule, therefor aldosterone also increases blood volume and pressure - When the body has too much sodium, aldosterone secretion is inhibited - Less sodium is reabsorbed and more is excreted - This causes the solute concentration to decrease in the extracellular fluid causing the hypothalamus to inhibit saliva production - The brain interprets the ensuing dryness as thirst Kidneys and blood pressure - Conditions that lead to increased fluid loss can decrease blood pressure, reducing the delivery of oxygen and nutrients to tissues - Blood pressure receptors found near the glomerulus detect low blood pressure, releasing renin (inactive) - Angiotensin is released from the juxtaglomerular apparatus - Constricts blood vessels, increasing blood pressure (increases blood volume)  - Angiotensin also stimulates the release of aldosterone from the adrenal gland - Increases sodium and water reabsorption, increasing blood pressure (increases blood volume) PH balance - Food and fluids consumed vary in PH level, but body remains at constant 7.3-7.5 - During cell resp. Cells produce carbon dioxide that forms carbonic acid - Carbonic acid and other excess acids ionize to produce H+ ions - Build up of H+ ions lowes pH of blood - Carbonic acid bicarbonate ion buffer system and breathing work to maintain blood pH - H2O (l) + CO2 (aq ) → H2CO 3(aq ) → HCO3 (aq ) + H +(aq) - Excess H+ ions are buffered by bicarbonate ions in the blood producing carbonic acid (weak acid) - Carbonic acid breaks down to form carbon dioxide and water - Carbon dioxide gets transported to lungs and exhaled bringing the pH level up - The buffer removes excess H+ ions but also needs to be restore - Kidney helps to restore the buffer by reversing the reaction - carbon dioxide is actively transported from the peritubular capillaries into the cells that line nephron - Water combines with carbon dioxide to generate H+ ions and bicarbonate ions - Bicarbonate ions diffuse back into blood and restore the buffer - H+ ions recombine with phosphate ions or ammonia and are secreted with urine - Kidneys also regulate pH - Mechanism is slower than buffer system, but more powerful - Kidneys needs to reabsorb HCO3- ions and excrete H+ ions as needed - If blood is basic - H+ ions are NOT excreted and bicarbonate ions are not reabsorbed - Since urine is usually acidic, excess H+ are being excreted - Many disorders can be detected by urinalysis - Endocrine System 2 main control systems: Nervous system: - works by nerve impulses (fast electric signals along nerves) - Travels fast and usually have ‘instant effect’ - Response is short lived - Impulse acts on individual cells (localized effects) Endocrine system - works by hormones transmitted in blood stream - Travel slowly and may take longer to act - Response is usually longer lasting - Widespread effects on different organs (with correct receptors Endocrine system - A system of glands located in various parts of the body: carries out its control via hormones - Acts as chemical messengers that are secreted directly into the blood or ECF - Travels to tissues or organs - Generally binds to a specific plasma protein carrier - Most encounter ‘target organ’ to be effective Endocrine glands vs exocrine glands Endocrine glands: - Ductless, secretory organs that secrete their hormones directly into blood or ECF (ex. Adrenal glands, thyroid gland) Exocrine glands: - Release secretions into ducts that lead outside the body or into body cavities (ex. Sweat and salivary glands) Types of hormones a) Protein hormones: - Contains chains of amino acids, hydrophilic (soluble in water) (ex. Growth hormones, insulin) b) Steroid hormones - Made from cholesterol (lipid compound)  - Composed of complex rings of carbon, hydrogen, and oxygen molecules - Hydrophobic, insoluble in water (ex. Sex hormones, cortisol, aldosterone) Pathways for water-soluble hormones (protein hormones) - Can diffuse well though blood and ICF, but cannot against membranes - Binds to receptors on the cell membrane - Forms a hormone-receptor complex that activates the production of adenylyl cyclase - Causes the cell to convert ATP into cyclic adenosine monophosphate (cyclic AMP), functioning as a messenger, activating enzymes in cytoplasm to carry out their normal functions Pathways for lipid-soluble hormones (steroid hormones) - Diffuse into capillaries into interstitial fluid and then into target cells - Can easily cross membranes - Bind to receptor c=molecules located in the cytoplasm - Hormone receptor complex then moves into the nucleus and binds to a control sequence on a gene - The hormone activates/deactivates a gene, therefore changing cellular activity The hypothalamus and pituitary gland Get off the damn phone. 📳 Us→ Its giving BRAIN The hypothalamus - Region of the brain that releases hormones from the pituitary gland - Hormones are secreted from the nerve ends of the cells of the hypothalamus and then the transported in the blood (via the portal vein) into the pituitary gland - It is under the control of the nervous system  - Negative feedback systems help to control how the hypothalamus releases its hormones Hormones released by the hypothalamus - Each type of hypothalamic hormone either stimulates or inhibits production or secretion of an anterior pituitary hormone - growth-hormone -releasing hormone (GHRH): stimulates the release of growth hormone (GH) from anterior pituitary - Corticotropin-releasing hormone (CRH): stimulates the release of ACTH from anterior pituitary - Thyroid-releasing hormone (TRH): stimulates the release of thyroid-stimulating hormone (TSH) Gonadotropin-releasing hormone (GnRH): stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from anterior pituitary Hormones produced by the hypothalamus: - The hypothalamus produces 2 hormones that are both stored and released by the posterior lobe of the pituitary: - Antridiuretic hormone (ADH): - Regulates blood pressure and promotes reabsorption of water by the kidneys - Oxytocin: - Induces labour (stimulates the contractions of the uterus and dilation of the cervix) and milk release from the mammary glands in females - In males, oxytocin is secreted into seminal fluid. When ejaculated into the vagina, it stimulates contractions of the uterus (aids movement of sperm) The pituitary gland - is often referred to as the ‘master gland’ because it exercises control over other endocrine glands - However, the hypothalamus stimulates the release of hormones of pituitary gland by way of nerves - This small sac-like structure (about one centimetre in diameter) is connected by a stalk to the hypothalamus and then transported in the blood (via the portal vein) into the pituitary gland - It is under the control of the nervous system - Negative feedback systems help to control how the hypothalamus releases its hormones The posterior lobe of the pituitary gland - stores and releases ADH and oxytocin that were produced in the hypothalamus, into blood when necessary The ANTERIOR lobe of the pituitary gland (Anterior lobe produces its own hormones unlike posterior lobe. Release of hormones is dictated by hypothalamus) - thyroid-stimulating hormone (TSH) & growth hormone: role of metabolism - Adrenocorticotropic hormone (ACTH): involved in the stress response - Follicle stimulating hormone (FSH) & Luteinizing hormone (LH): role in reproduction - Prolactin (PRL) - Influences reproductive activities - During pregnancy, it contributes to development of the mammary glands, and after birth, it stimulates the mammary glands to produce breast milk The INTERMEDIATE lobe of the pituitary gland?? - in humans, the intermediate love is not well developed and is seen only as a collection of cells located between the lobes of the pituitary, however it produces or releases the following hormones - endorphins: - Protein hormones produced by the hypothalamus and pituitary gland - Are released by the intermediate lobe of the pituitary gland - Endorphins act as neurotransmitters in pathways that control pain (natural pain killers) Melanocyte-stimulating hormone (MSH) - Target issue- melanocytes (skin cells that contains the black pigment melanin) in the skin - Promotes darkening of the skin Hormones that affect Metabolism Thyroid Gland - Located at base of the neck, in front of the trachea  - Consists of 2 lobes (looks like a bow tie) Thyroid Hormones - Vital to growth, development ,maturation and metabolism - Secretion of hormones is governed by the anterior pituitary gland which produces TSH - activated by TRH - TSH- stimulates thyroid gland to increase in size and secrete thyroid hormones Thyroxine (T4) (four iodine) - Primary thyroid hormone - Contains 4 iodine atoms - Derived from amino acid tyrosine Triiodothyronine (T3) - Secreted in smaller amounts - Both T4 and T3 enter cells BUT once inside, most of the T4 is converted to T3 (the form that combines with internal receptors) - Binding of T3 to receptors- alters gene expression which brings about the hormones effects (increases metabolic rate) Hypothyroidism (under-active thyroid) - Low thyroid output - Decreased T4 and T3 = decreased rate of oxidation of glucose and other materials - Excess blood glucose stored as glycogen/fat (long term) - Leads to weight gain Symptoms: - Sluggish mentally and physically - Intolerance to cold (cell resp is lower, it emits heat) - Weight gain - Decreased heart rate Treatment: - Drugs Hyperthyroidism (overactive thyroid) - Overproduction of thyroid hormones (TSH receptors active) - Increased t4/t3=increased rate of oxidation of glucose and other materials - 60% oxidized and released as heat, 40% transferred to ATP - Most common - graves disease - Autoimmune disorder  - Antibodies attach to TSH receptors, turning them ON constantly (thyroid turns on and continues making thyroid hormones even if it doesnt need) SymptomsSymptoms: - High body temperature - Profuse sweating - Weight loss (fast metabolism of glucose) - Irritability - Rapid and irregular heartbeat Treatment: - Surgical removal of thyroid gland - Anti-thyroid medications - Radioactive iodine that destroys overactive thyroid tissue Goiter: - Causes: - Less iodine in body = less thyroxine (T4) produced - Thyroid continuously stimulated by TSH - Over stimulated thyroid swells (produces goiter) Calcitonin - Protein hormone - Lower Levels of Ca2+ in the blood by inhibiting the relapse of Ca2+ from bones 1. Blood Ca2+ levels 2. Thyroid gland 3. Calcitonin 4. Stimul Parathyroid gland - Mammals have 4 parathyroid glands embedded in the surface of the thyroid - Produces parathyroid hormone (PTH) - Protein hormone - Secreted in response to decreases in Ca2+ in the blood Parathyroid hormones (PTH) 1. Blood ca levels decrease 2. Parathyroid gland 3. PTH 4. - Stimulates ca2+ uptake/reabsorption in kidneys - Stimulates release of Ca2+ release from bone - Increases ca2+ uptake intestines  5. Increase levels of Ca2+ to setpoint PTH underproduction - Causes Ca2+ concentrations in blood to fall steadily - Nerve and muscle function disturbed - Muscles twitch and contract uncontrollably leading to convulsions and cramping - Fatal of untreated because muscular contractions interfere with breathing PTH overproduction - Results in loss of calcium from bones - Makes bones brittle and fragile (osteoporosis) - Elevated Ca2+ in blood causes calcium deposits to form in soft tissue (kidney stones) Growth Hormone (somatotropin) - Produced by anterior pituitary gland - Stimulates body growth (ie cell division, protein synthesis) - GH binds to muscle and other target tissue - Causes them to release insulin like growth factors (IGF) - Protein hormones that directly stimulates growth -(causing elongation of skeleton) - Soft tissue and bone - grow by increasings # of (hyperplasia) and size of cells (hypertrophy) Acromegaly - GH is increased after cartilage plates are fused - Long bones don’t respond but others do (ex. jaw) Underproduction of GH - Pituitary dwarfs (dwarfism) - Remain small in stature Overproduction of GH - Pituitary Giants (gigantism) - Ie. result of a tumor on anterior pituitary Hormones that affect blood sugar Pancreas: - Consists of mostly exocrine tissue that produces digestive enzymes and exports them to the small intestine - Endocrine cells are located in the Islets of Langerhans Islets of Langerhans - 2 regions - Alpha cells: secrete the protein hormone GLUCAGON - Beta cells: secrete the protein hormone INSULIN Ur gettingtouched you are my beta 💗 don’t make me give you that radiohead 📻👏 Hormone Where its function Mode of action produces Insulin Beta cells Lowers blood Causes cells of muscles, liver and other sugar levels organs to be more permeable to glucose, increases the uptake of glucose from the blood Glucagon Alpha cells Raises blood Stimulates the breakdown of glycogen sugar levels into glucose Increases the release of glucose into blood Insulin and Glucagon feedback → Diabetes Mellitus - Caused by a deficiency of insulin or loss of response to insulin in target tissue - Leads to high blood glucose levels Three Types of Diabetes Mellitus Type 1 (Juvenile or insulin Dependent) - The immune system attacks the beta cells in the pancreas and body loses the ability to produce insulin - Treatment: insulin injections  Type II (adult-onset or insulin resistant) - Characterized by a deficiency of insulin or reduce responsiveness in target cells cause by a change in insulin receptors - Associated with obesity - Can develop into type 1 - Treatment: controlling diet, exercise, medication, insulin injections Gestational Diabetes - Temporary (usually) condition that occurs in 2-10% of pregnancies - Increases risk of diabetes in mother and child Classic Symptoms 1. Frequent urination - Increased blood glucose causes kidneys to be unable to reabsorb all glucose, causing an increase in the glucose in the nephron leading to more water being drawn from the blood into the nephron by osmosis 2. Increased thirst - Need to replace the excessive amounts of urine 3. Increased appetite - Body cells do not get enough glucose Hyperglycemia - High blood sugar Two kinds: - Postprandial / after-meal hyperglycemia - Blood sugar higher than 180 mg/dL two hours after you eat - Fasting hyperglycemia - Blood sugar higher than 130 mg/dL after not eating or drinking for 8 hours Causes: - Forgot insulin - Ate too many carbs - Infection or illness - Stress - Little exercise Symptoms: - Increased thirst - Weight loss  - Headache - Fatigue - Frequent urination - Vaginal and skin infections, damage to eyes, blood vessels or kidneys, ketoacidosis (diabetic coma) (in severe cases) Hypoglycemia - Low blood sugar, lower than 70 mg/dL Causes: - Certain medications to treat diabetes - Not enough carbohydrate intake or insulin takers Symptoms: - Sonfusong and dizziness - Sweating - Shaky feeling - Hunger - Headaches - Irritability - Poor concentration and coordination, numbness in mouth and tongue, passing out, coma (in severe cases) Adrenal Gland & Stress Response Adrenal glands: - Located above the kidneys - Made up of 2 glands with different cell types and functions: - Adrenal cortex: outer religion surrounding medulla - Adrenal Medulla - central region Adrenal Medulla - Under nervous system control - 2 hormones released - Epinephrine (adrenaline) - Norepinephrine (noradrenaline) - Regulates the body's short term stress response  - Secreted when the body encounters stresses (emotional excitement, danger, – fight or flight, anger, fear, injury) Epinephrine - Prepares the body for handling stress or physical activity Effects of epinephrine on the body 1. HR increases (heaRT RATE) 2. Glycogen and fats are broken down for fuel 3. Blood vessels dilate to increase blood flow in heart, lungs and skeletal muscles 4. elsewhere, blood vessels constrict – increase BP therefore reducing blood flow to intestines and kidneys, therefore slowing down digestion and water loss 5. Airways in lungs dilate to increase air flow increasing BR 6. Iresis of eyes dilate Effects of Norepinephrine - Effects on HR, BP and blood flow to the heart is similar to epinephrine - In contrast to epinephrine, blood vessels in skeletal muscles constrict - Antagonistic effect is largely cancelled out because epinephrine is secreted in much larger quantities Adrenal cortex - Responds to endocrine signals - Long term stress response - Stress-stimuli causes the hypothalamus to secrete CRH (corticotropin-releasing hormone) that stimulates the anterior pituitary gland to release ACTH (adrenocorticotropin – also called corticotropin) - ACTH stimulates the cells of the adrenal cortex to secrete a family of steroids called corticosteroids Corticosteroids 1. Glucocorticoids - Associated with blood glucose levels - More glucose is available for cell recovery - Cortisol is the major glucocorticoid secreted Cortisol - Steroid hormone  - Main job is to raise levels of blood glucose - Reduces glucose uptake by cells - promotes glucose synthesis from non-carbohydrates - Increases blood amino acid levels by promoting the break down of muscle protein; amino acids released are converted to glucose in the liver and returned to the blood - Adipose tissue is converted to fatty acids - Natural anti-inflammatory - Harmful long-term because it results in immunosuppressive effects 2. Mineralocorticoids - Major effects on salt and water balance - Aldosterone stimulates cells in the kidney to reabsorb sodium ions, which causes water reabsorption (increase in blood volume) and raises BP 3. Gonadocorticoids (sex hormones) - Supplement the reproductive hormones produced by gonads Other endocrine glands: Pineal gland: - Small mass of tissue near the centre of the brain - Secretes melatonin to regulate biological rhythms - Melatonin is secreted at night which helps synchronizes the biological glock with daily cycles of light and darkness Thymus: - Lies across the front of the neck - Large during childhood and diminishes in size when immune system - Secretes thymosin – stimulates the development of T-lymphocytes Adjustments to Stress - In response to stress, both endocrine and nervous systems make adjustments that enable the body to cope - nervous system – rapid, short term adjustments to stress - Sympathetic nerves stimulate adrenal medulla to release epinephrine and norepinephrine - Endocrine system – slower, long term adjustment in which hormones provide sustained response to stress stimulus - Ex. cortisol – released by adrenal cortex – stimulated by ATCH from anterior pituitary and CRH from hypothalamus Stress hormones: - Increase blood glucose – needed for elevated energy requirements - Inhibit insulin release – to maintain elevated blood glucose levels - Increase bP and blood volume - Increase of ADH - helps maintain body fluids Athletic stress - Increase in cardiovascular activity = increase in oxygen delivery to tissues for cell resp. = atp synthesis - Emotional or psychological stress - No physical outlet, making it more difficult to adjust to, cortisol levels always high, bad for blood vessels - Modern day problem - Difficult to adjust because increase energy supply is not always used - Long term stress = prolonged exposure to high blood glucose, BP and metabolic rate = problems for the body Prostaglandins - 16+ different hormones enzymatically derived from fatty acids - Produced by mediator cells in response to changes in immediate, local environment of cells - Secreted in low concentrations but secretions increase when changes take place - Potent but have short half-life before being inactivated and excreted, therefore, exert only an autocrine (act on the same cells from which it synthesized) or paracrine (locally active) function. They are absorbed quickly by surrounding tissues and few are absorbed by capillaries and carried in the blood - In response to stress: - Increased blood flow to local tissues - Relax smooth muscle in passages leading to lungs - Released during allergic reactions Chemically enhanced sports performance - Caffeine gives you an advantage during races/competitions - Mimics epinephrine (adrenaline) - Increases heart rate, BP and alertness - Anabolic steroids - Mimic muscle building traits of testosterone does not increase skills or oxygen delivery - Banned from competitive sports  - Hazards - Causes premature bone fusing of growth plates, decreases height potential - Causes mood swing, baldness, acne, bad breath, high BP, liver disease, cancer - In males: breast development, reduced sperm production leading to testicular atrophy - In females: breast reduction, changes reproductive cycle, increases body hair, deepening of voice - Beta blockers - Slow heart beat to steady nerves and aim used by sharpshooters and archers - Growth hormone (natural and artificial) - Decreases fat deposits and promotes synthesis of proteins - Enhances muscle development - Erythropoietin (EPO) - Increases RBC production = oxygen delivery to cells = increase in endurance and energy - Erythropoietin and growth hormone are more difficult to detect because they occur naturally Male and female reproductive hormones Parts of the male reproductive system structure function testes - Produces sperm cells - Produces testerone hormone Seminiferous tubules - Produces immature sperm cells epididymis - Matures and stores sperm cells in coiled tubules Vas deferens - Carries sperm from epididymis to its junction with the urethra Seminal vesicle - Secretes fructose into semen, provides energy for semen Prostate gland - Secretes alkaline buffer into semen to protect sperm from acidic environment of vagina Cowper's gland - Secretes mucus rich fluids into the semen that may protect the sperm from acids in the urethra urethra - Carries semen during ejaculation - Carries urine from bladder to exterior of body penis - Deposits sperm into the vagina during ejaculation - Contains the urethra Parts of female reproductive system structure function ovaries - Produces the hormones estrogen & progesterone - Site of ova (egg cell) development and ovulation Fallopian tubes (oviducts) - Carry the ovum from ovary to uterus fimbria - Sweep the ovum into the fallopian tube following ovulation Uterus (womb) - Pear shaped organ in which embryo and fetus develop - Involved in menstruation Cervix - Separates vagina from uterus - Holding fetus in place during pregnancy - Dilates during birth to allow fetus  to leave uterus Vagina - Extends from cervix to external environment - Provides passageway for sperm and menstruation flow - Functions as the birth canal Hormonal control of the male reproductive system 1. At puberty, the hypothalamus secretes gonadotropin-releasing hormone (GnRH) 2. GnRH activates the anterior pituitary gland to release follicle stimulating hormone (FSH) & luteinizing hormone (LH) 3. FSH travels in the bloodstream to the testes where it acts directly on the Sertoli cells of seminiferous tubules - Sertoli cells: are supportive cells that completely surround the developing spermatocytes in seminiferous tubules: providing nutrients - Produce the hormone called inhibin that sends a feedback message to anterior pituitary gland inhibiting production of FSH 4. LH travels in the bloodstream to testes where it stimulates the interstitial cells (Leydig Cells) to produce testerone 5. Testosterone primary function is to increase sperm production - spermatogenesis: production and development of sperm cells in the testes 6. High levels of testosterone in blood, travels to brain and is detected by both the pituitary gland and hypothalamus 7. This causes a decrease in GnRH production which inhibits the release of FSH and LH Hormonal control of the female reproductive system 1. At puberty, the hypothalamus secretes gonadotropin-releasing hormone (GnRH) 2. GnRH activates anterior pituitary gland to release follicle stimulating hormone (FSH) and luteinizing hormone (LH) 3. FSH travels in the bloodstream to ovaries and stimulates the development of an ovum sac-like follicle 4. The follicle enlarges and starts producing estrogen  - Estrogens effects - Thickens the endometrium - Develops breast tissue - Blocks FSH production - Stimulates the anterior pituitary gland to release LH 5. LH travels in the bloodstream to a follicle in the ovary where it causes this follicle to rupture, which releases the ovum. This is called ovulation (the ovum only lives 24-72 hours) 6. The ovum is swept into the fallopian tube by the fimbriae 7. The estrogen levels drop and the ruptured follicle becomes the corpus luteum 8. The corpus luteum produces the hormone progesterone - Progesterone effects: - Blocks FSH and LH production - Develops breast tissue - Thickens endometrium - Inhibits further ovulation - Inhibits uterine contractions 9. If the ovum is fertilized, it becomes a zygote. The zygote then begins to divide and implants itself on the endometrium of the uterus 10. This causes a decrease in GnRH production which inhibits the release of FSH and LH Female menstrual cycle List of hormones: Hormone gland target function ADH (antidiuretic Posterior pituitary Kidneys Increases water reabsorption in nephron hormone) tubules oxytocin Posterior pituitary Uterus and Initiates contractions for childbirth and mammary triggers milk release in lactating women glands STHRH/GHRH hypothalamus Anterior Stimulates synthesis and secretion of GH pituitary STH/GH Anterior pituitary Most cells Promotes growth GRH hypothalamus Anterior Stimulates release of ACTH pituitary ACTH Anterior pituitary Adrenal cortex Stimulates release of hormones involved in stress response, such as glucocorticoids, etc Glucocorticoid Adrenal cortex Liver and Stimulates conversion of protein and fat immune into glucose system Suppresses inflammatory response TRH hypothalamus Anterior Stimulates release of TSH and PRL pituitary TSH Anterior pituitary thyroid Stimulates release of T4 T3 and T4 thyroid Body cells Increase metabolic rate, increases heart rate and strength of heartbeat GNRH hypothalamus Anterior Increases releases of FSH and LH pituitary FSH Anterior pituitary Ovaries and Females: stimulates follicle to release testes estrogen Males: stimulates spermatogonia to produce sperm LH Anterior pituitary Females: Females: stimulates follicle to release follicle estrogens and develop[s into corpus Males: testes luteum Males: stimulates interstitial cells to  release testosterone PRLRH hypothalamus Anterior Stimulates release of PRL pituitary Prolactin Mostly anterior Mammary Helps preparation of future milk during pituitary, but many glands pregnancy (before) other cells Promotes synthesis of milk (after) pregnancy calcitonin thyroid Bone cells, Suppresses osteoclasts (bone cell kidney digesting cells)- decreasing calcium and phosphorus levels in blood Decreases reabsorption of CA and P in kidneys PTH Parathyroid Mostly bone Regulates calcium and phosphorus levels and kidney in ECF Extremely important in humans Insulin Beta cells of the Islets Skeletal Stimulates cells take up glucose and of Langerhans in muscles, liver, convert it to glycogen or fat, decreasing pancreas fat cells blood glucose Glucagon Alpha cells in the islets liver Stimulates conversion of glycogen into of Langerhans in glucose, increasing blood glucose pancreas Somatostatin hypothalamus Anterior pituitary Inhibits release of DH Inhibits release of TSH Melatonin pineal Not well understood Regulates sleep/wake up cycles (circadian rhythm) thymosin thymus Lymph nodes Stimulates immunological activity of lymphoid tissue Mineralocorticoid Adrenal cortex kidney Promotes reabsorption of Na+ ions Water follies increasing blood volume and BP Adrenalin Adrenal medulla Many cell types - heart beats faster and stronger - blood shunted Noradrenalin away from skin and viscera to the skeletal muscles, brain, coronary arteries - rise in blood sugar - increased metabolism - pupils, bronchi dilate - pilomotor response - prepare body for immediate and  vigorous action estrogen Ovaries of mature females Many target tissues Responsible for sexual maturation of women Participates in monthly menstrual cycle Participates in pregnancy progesterone Corpus luteum and endometrium Prepares endometrium for placenta possible pregnancy Secretion maintained if pregnancy occurs HGC Trophoblast of a Corpus luteum Prevents disorientation of blastocyst (embryo) corpus luteum after fourth week and allows pregnancy to continue commonly tested for in pregnancy tests testosterone Interstitial cells of testes Many cell types Develops secondary sexual characteristics Sperm production ANH Atria of heart kidneys Regulates BP by excreting more salt from kidneys Somatomedin liver Muscle and bone Insulin-like growth hormone renin kidney angiotensinogen Converts angiotensinogen into angiotensin || Causes several changes with result in increased blood pressure Erythropoietin (EPO) Stomach and duodenum Gastric cells of stomach Stimulates exocrine cells of stomach to secrete gastric juice Gastrin Stomach and duodenum Gastric cells of stomach Stimulates the exocrine cells of stomach to secrete gastric juices Secretin duodenum pancreas Stimulates pancreas to release bicarbonate ions into pancreatic fluid