Homeostasis: Organ System Interaction (ZOOLEC Notes PDF)

Ika Baquir Block 13D 1 BS Life Sciences ZooLec Homeostasis: Organ system interaction promote Negative feedback...

Ika Baquir Block 13D 1 BS Life Sciences ZooLec Homeostasis: Organ system interaction promote Negative feedback = common way to Homeostasis maintain homeostasis Introduction Hypothalamus - Supervisor that Animal’s body must maintain internal coordinates much of action temperature, blood pressure, chemical composition of fluids within certain limits Animal’s body consists mostly of water ○ Some moisture makes cytoplasm of every cell ○ Rest forms blood plasma and interstitial fluid that bathes body cells Interstitial fluid = part of internal environment because its inside body but outside cells Controlling Body Temperature ○ Many organ systems interact to Temperature needs to be constant at 37 C help maintain correct ○ Also temperature for enzymes concentrations of nutrients, salts, ○ Body balance amount of heat hydrogen ions, ad dissolved gases energy gain and lost through in body fluids respiration Homeostasis = processes by which body Hypothalamus in brain has receptors controls its internal environment sensitive to temperature of blood in bran Complementary activity of major body ○ Thermoregulatory center also systems maintains homeostasis receives impulses from skin providing info about skin Why is it important for all organisms to maintain temperature homeostasis? Different responses produced by effectors No stable internal environment = body to counteract increase/decrease on temp stops functioning, disease may result, What happens if you are too hot? organism may die ○ Hair flat ○ E.g. water in lungs = no longer ○ Sweat produced and evaporates acquire O2 or dispose of CO2 yet from skin to remove heat cells continue to respire ○ Blood vessels supplying vessels ○ Soon all available O2 will be dilate so blood flows closer to consumed = hypoxia and CO2 will surface accumulate to toxic levels = blood Makes easier for heat to acidic = cells die = person will be transferred from blood drown to environment Homeostasis = balancing inputs and What happens if you are too cold? outputs for internal environment ○ Hairs stand up Body has automatic control systems that ○ No sweat regulate internal environment ○ Blood vessels supplying skin ○ E.g. system that maintains capillaries constrict to close off temperature, blood glucose, water skin’s blood supply content ○ Shiver All automatic control systems have 3 main ○ Needs respiration = releases components energy to warm body ○ Receptors ○ Processing centers Controlling Blood Glucose ○ Effectors Ika Baquir Block 13D 1 BS Life Sciences ZooLec Glucose = source of energy for mammalian cells Type 1 - Pancreas produces little to no ○ Eating foods rich in CHO put Diabetes insulin glucose into blood from gut 1. Avoid food rich in CHO Normal metabolism of cells remove 2. Inject insulin during glucose from blood mealtimes What happens when you eat food containing CHO? Type 2 - Pancreas produces insulin but body Diabetes fails to respond ○ Digestive system breaks carbs - Late onset diabetes (Develops late into glucose which enters blood in life) ○ Glucose = energy substrate of - Poor diet or being obese increases brain risk Disturbances in blood 1. Eating food high in complex glucose cause disease CHO and fibers because and death they are digested slower so sugar is absorbed into blood Blood glucose over longer period of time concentrations must be within narrow limits ○ Pancreas = monitors and controls Positive Feedback the blood glucose changes Only few functions demonstrate positive Makes use of hormones feedback insulin and glucagon ○ Positive feedback = body reacts to Hormones released into change by amplifying it bloodstream in response ○ Other controls cut off positive to change feedback loop and restore equilibrium Childbirth = Example of Positive Feedback ○ Stretching of uterus triggers secretion of oxytocin by pituitary gland to speed up labor Blood clotting = Example CHO foods put blood sugar level up ○ Cut blood vessel constricts ○ What happens if a person cannot ○ Platelets aggregate in injured site keep blood sugar steady? if the ○ Proteins called clotting factors pancreas fails to produce insulin? activate other clotting factors in = Diabetes Mellitus positive feedback loop Ika Baquir Block 13D 1 BS Life Sciences ZooLec ○ Resulting complex series of reactions end with formation of blood clot How does the Integumentary system maintain Homeostasis? Your Skin ○ Keratinocytes = cells that produce keratin (protein) ○ Stratum corneum (outermost layer) = composed of highly keratinised stratified squamous Skin maintains homeostasis = body epithelium tissue temperature regulation by negative ○ Tough dry keratin protects skin feedback mechanism from disease causing Function of skin microorganisms (pathogens) ○ Abundant nerves, blood vessels, abrasion, heat, chemicals eccrine glands within dermis Melanin (pigment) = absorbs ultraviolet (skin’s deepest layer) help control radiation that can damage DNA body temperature ○ Melanocytes = produces melanin Response to high environmental ○ UV light exposure stimulates temperature melanin production ○ Hypothalamus stimulated blood ○ Darker skin, higher melanin vessels in skin to dilate = releasing concentration heat from deeper tissues to ○ Variation of different skin colors = surroundings same number of melanocytes but ○ Perspiration pours out from sweat differ in amount of melanin glands produced Response to low environmental Langerhans cells = carries out protective temperature functions that are immunologic in nature ○ Skin blood vessels constrict = ○ Cells induce first reactions against keep warm blood away from disease causing microorganisms body’s surfaces on skin ○ Production of sweat decreased ○ Macrophages in dermis Skin/Integument = one line of physical phagocytose bacteria and viruses protection that manage to penetrate skin ○ Skin serves as primary defense Cutaneous sensations = when epidermal mechanism from invaders cells detect touch, pressure, vibration, ○ Waterproof barrier that prevents thermal sensations, tickling entry of water ○ Sensory nerve fibers originate in ○ Keeps underlying tissues moist nerve root along spine and supply preventing dehydration sensations to specific areas of skin Epidermis has 5 strata (layers) = protective known as dermatomes function ○ Dermatomes = areas of skin that rely on specific nerve connections on your spine Ika Baquir Block 13D 1 BS Life Sciences ZooLec ○ Nerve fibers transmit sensations As injury heals, from skin to central nervous replacement skin system contains more collagen ○ Autonomic nerve fibers carry fibers than undamaged impulses to smooth music in walls epidermal skin layer of skin’s blood vessels, to muscles Resulting scar consists of around hair roots, to sweat glands new skin not like old Pain = important cutaneous sensation Also lacks hair follicles ○ Indication of tissue damage and sweat glands ○ Alerts body to potential damage Oily sebum from sebaceous glands = ○ Body's way of telling you protect skin and hair from drying out something is not right ○ Also contains bactericidal Referred pain = pain in one part of body is chemicals/antimicrobials that act caused by injury in another part as innate immune system of skin ○ E.g. heart attack shows up as referred pain in left shoulder Never underestimate how much someone hurts Hair = emerges from epidermis ○ Grows from follicle anchored in dermis ○ Cells at base of hair follicle divide Sweat glands = originate in dermal layer of pushing daughter cells passing oil skin glands along the way ○ Produce sweat = removal of water ○ Cells stiffen with keratin and die to and heat by evaporation form hair Excretes small amount of Functions of hair salts, CO2, ammonia, ○ Camouflage urea ○ Skin senses cold = hairs stand ○ Water cannot penetrate skin but because of smooth muscle tissues certain lipid soluble materials can surrounding follicles Lipid soluble vitamins Goosebumps (ADEK) This provides insulation Gases O2 and CO2 that prevents body heat ○ Collagen large protein = cannot Functions of tissue cells that make up penetrate skin to help synthesize dermis collagen fibers ○ Dermal layer = collagen fibers Vitamin D = synthesized by skin ○ Protein fibers = synthesized by ○ UV strikes skin = activates principal cells of dermis called precursor of vitamin D fibroblasts ○ Enzymes in liver and kidney ○ Collagen= provides strength and modify activated molecule elasticity to skin producing calcitriol ○ Scar = left because of injuries that damage dermis Ika Baquir Block 13D 1 BS Life Sciences ZooLec ○ Calcitriol = most active form of Too much or too little Vitamin D water is drawn into cell by Helps absorption of osmosis calcium in food from ○ Wrong amount of water damage gastrointestinal tract into cells and function blood So kidneys remove Regulate calcium and excess ions phosphate concentration Also why some in blood for bone strength ions are also lost in sweat The Kidneys and Homeostasis ○ E.g. kidneys will remove excess Your Kidneys sodium ions from blood if you eat high salt meal with too much sodium Adjustment of water content ○ Water taken into body as food and drink Secreted in three ways: urine, sweating, or breathing Body cannot control breathing Body has to balance water in and water out Kidneys = filters to clean blood Liquids Function of kidney consumed, ○ Removal of urea from blood amount sweated ○ Adjustment of ions in blood out, amount ○ Adjustment of water content excreted by ○ Regulation of blood volume and kidney in urine composition ○ Water lost when hot has to be ○ Regulation of of blood pressure replaced with water from food and ○ Contributes to metabolism drink Removal of urea from blood Nephrons = functional units of kidney ○ Proteins not stored by body ○ Kidney = 1.3 nephrons Liver = Excess amino ○ Capillaries = entwines nephrons acids are converted to fat Function of nephrons and carbs to be stored ○ Filtration Urea = waste from the ○ Reabsorption process above, poisonous ○ Secretion ○ Liver releases urea into blood stream and kidney filters it out of blood ○ Urea stored as urine in bladder and excreted from body Adjustment of ion content ○ Ions such as sodium taken into the body from food then absorbed in blood Ion of water content wrong = upset balance of ion and water Ika Baquir Block 13D 1 BS Life Sciences ZooLec Filtration ○ Hormones help ○ High pressure built up which ○ When water is scarce, squeezes water, urea, ions, and osmoreceptors in hypothalamus sugar out of blood and into send impulses to posterior glomerular capsule (Bowman’s pituitary gland capsule) ○ PPG secretes hormone called ○ Filters = membranes between antidiuretic hormone (ADH) blood vessels and glomerular (vasopressin) capsule ADH = triggers reabsorption of water ○ Big proteins and blood cells are ○ Urine becomes more not squeezed out and stay in concentrated blood Water content too high = ADH production ○ Presence of protein in blood stops = kidney reabsorbs less water = (proteinuria) = kidney damage more water eliminated in urine sine Water content regulation = negative ○ Presence of blood in urine feedback (hematuria) = infection or kidney ○ More water kidney absorbs, less stones or stones in bladder water passes as urine Reabsorption Some drugs interfere with affairs that ○ Liquid flows along nephron = increase urine volume useful substances like salts, water, ○ Diuretic = substance that increase glucose, amino acids return from volume of urine nephron to blood E.g. alcoholic beverages Active transport = Alcohol = suppresses production of ADH against concentration ○ Kidney reabsorb less water gradient ○ Since more water loss to urine = ○ Sufficient ions reabsorbed, excess intensify thirst ions not ○ Dehydration = hangover ○ Sufficient water reabsorbed Kidneys regulate blood pressure = secreting enzyme renin ○ Renin = activates renin-angiotensin pathway -> increase blood pressure Hormones adrenal glands act on kidney = regulate blood pressure ○ BP low, adrenal cortex (outer portion of adrenal gland) releases steroid hormone aldosterone Aldosterone = stimulates production of sodium channels in distal Secretion convoluted tubule ○ Toxic substances like urea, Water follows Na+ ions by creatinine, drug residues, osmosis = blood volume hydrogen ions, surplus ions, are increases = BP rises secreted into nephron, into ureter, down to bladder as urine Nephrons = maintain homeostasis of blood and urine is produced Hormones regulate kidney function Kidneys = adjust ion and water content Ika Baquir Block 13D 1 BS Life Sciences ZooLec The Homeostatic Role of the Lymphatic and Immune System Lymphatic system maintains circulation and protects against infection Lymphatic system = bridge of circulatory and immune ○ Blood circulation = RBCs remain confined to capillaries but many components of blood can pas between endothelial cells that make capillary walls ○ Fenestra = pores within endothelial cells For maintenance of Kidneys = do major work in urinary system normal endothelial for homeostasis functions, blood ○ Also help in Metabolism homeostasis and survival Kidneys = synthesize new glucose molecules during periods of starvation or How do fluid leaks out of blood vessels return to fasting the circulatory system? ○ Secrete hormone erythropoietin Lymphatic system = network of lymph that stimulates RBC production capillaries that collect lymph fluid, remove ○ Vitamin D synthesis bacteria, debris, cancer cells, and return fluid to the blood Lymph = colorless fluid of lymphatic system ○ Similar to blood plasma except proteins too large to pass through fenestrae Lymph nodes = where lymph passes, cleanses lymphs which return to blood stream ○ Inside are WBCs that fight phagocytosis dead cells and pathogens (disease causing microorganisms) ○ During infection, lymph nodes in neck pits groin swollen and tender as they accumulate extra WBCs Do you notice pain behind ears, jaw, side of neck during cold or sore throat? Swollen lymph nodes (lymphadenopathy) = body’s natural reaction to illness or infection Lymphoid tissues that guard mucous membrane where pathogens can enter ○ E.g. tonsils, appendix, and patches of lymphoid tissues in small intestine Ika Baquir Block 13D 1 BS Life Sciences ZooLec How does the immune response contribute to ○ Nonspecific = acts on different homeostasis? invader types Kinds of WBCs ○ Protective mechanisms: physical ○ Neutrophils barriers such as skin, mucous ○ Eosinophils membranes, secreted mucus that ○ Basophils prevent organisms from entering ○ Monocytes internal tissues ○ Lymphocytes [1A] First Line of Defense: Physical Mast cells = non circulating cells Barriers Neutrophils and macrophages = arise from ○ Skin and mucous membranes of monocytes digestive respiratory urinary and ○ Phagocytes that engulf and reproductive tract = physical destroy bacteria and cellular barriers block pathogens debris Epithelial barriers B and T cells = lymphocytes produced in ○ Unpunctured epithelial barriers = red bone marrow and mature in thymus most extensive barrier prevents gland invasion of microorganisms Natural killer cells = lymphocytes ○ Motile cilia = on some epithelial Invertebrates = have various nonspecific cells (e.g. trachea) to sweep defenses but cannot make specific immune materials to areas to be expelled response and destroyed Vertebrates = have two lines of body ○ Skin and mucous membranes = defenses against foreign invaders and can have antimicrobial and mucus make specific immune responses secretions Types of human immune system body ○ Sweat and sebum = make skin defenses: acidic and inhibit of ○ Nonspecific defense mechanism microorganisms (Innate immunity) Skin pH level = 3.5 to 5.8 ○ Hydrochloric acid in stomach = makes stomach acidic which kills most organisms ○ Flushing act of urinary tract (urine flow) = washes out potential microbes For sterility ○ Saliva flow = removes organisms from oral cavity ○ Enzymes and chemical antimicrobial factors = active in blood, mucus, milk, phagocytes, other body sites ○ Body’s normal microbiota ○ Specific defense mechanism E.g resident microbes on (adaptive immunity) skin and gut prevents pathogens Nonspecific defense mechanism (Innate E.g. Lactic acid bacteria immunity) predominate in vagina ○ Innate = always present ready to during child bearing years function to discourage pathogens ○ Prevent pathogen entry/attack through acid pH pathogen ○ Nonspecific defenses work together Ika Baquir Block 13D 1 BS Life Sciences ZooLec E.g. nose removes 90% ○ Plasma = leaks into tissues inhaled particles accounting to swelling but also Mucus in nose rich in delivering antimicrobial lysozyme substances to dilute toxic Motion of ciliated cells in materials respiratory tract propel ○ Heat and redness = increased blanket of mucus from blood flow through dilated blood lungs vessels Normal microbiota ○ Pain = increased fluid in tissue and prevent growth of effect of chemical on sensory microorganisms nerve endings [1B] Second Line of Defense ○ Neutrophils = predominate in area ○ Destroys pathogens in a of inflammation generalized way ○ Neutrophils and macrophages = ○ Phagocytes engulf pathogens phagocytise foreign materials ○ Phagocyte (WBC) = found in ○ Clotting factors = in fluids that blood and tissues leak in tissue to prevent bleeding ○ Phagocytosis process: and inviting of organisms in clot Injured mammalian cell ○ As inflammation subsides, healing releases chemoattractant occurs to phagocyte Healing = new capillary Phagocyte attaches to blood vessels grow into microorganism and area, destroyed tissues attaches itself replaced, scar tissue Microorganism engulfed formed by phagocyte into ○ Chemical Defenses: Antimicrobial vacuole (phagosome) Biochemicals Lysosome come into Complement = group of contact with phagosome blood proteins act in and release enzymes into sequence vacuole (phagolysosome) Help destroy Within phagolysosome, pathogens microorganism digested Some trigger Lysosome contents chain reaction eliminated by exocytosis that punctures ○ Inflammation = immediate bacterial cell localized reaction to membrane injury/pathogen Others cause ○ Area surrounding wound becomes mast cells to red, warm, swollen, painful release Fifth sign = loss of histamine to function increase permeability of blood capillaries to WBCs and proteins for them to kill the pathogens Cytokines = messenger proteins that bind to immune system cells and Ika Baquir Block 13D 1 BS Life Sciences ZooLec promote cell division and Cytokines travel activate defenses through body in Include bloods interferons, At hypothalamus, interleukins, they trigger colony increase of stimulating body’s factors thermostat Act at low Higher body concentrations temperature = and short ranges, inhibits bacteria powerful and viruses by Interferons (IFN) = speeding up produced by virus body defenses infected cells Bacteria and Cytokines sound fungi require alarm to alert more iron as immune system temperature Molecules of IFN rises act on nearby Fever reduces cells to prevent iron level in replication of blood virus So pathogens Interleukins (IL) = can't replicate cytokines produced by Phagocytes = leukocytes attack more Induce fever when Contribute to temperature inflammatory rises response [2C] Specific Defense Mechanisms Release of (Adaptive Immunity) neutrophils from ○ Antigen = target in specific bone marrow immune response Then bind to Molecules (proteins or blood vessel polysaccharides) on walls surface of cells Colony stimulating When pathogens invade, factors (CSFs) = antigens on cell surface multiplication and activates immune system differentiation of cells leukocytes when more ○ Phagocyte engulf pathogen are needed Phagocyte recognises Fever helps fight infection antigen on pathogen Body temp = 37 Lysosomal enzymes break C by down pathogen thermoregulatory Phagocyte presens in hypothalamus pathogen’s antigens Hypothalamus Sticks antigen on surface controls to activate other immune temperature system cells blood flow sweat Antigen Presenting Cells (APC) = phagocytes Ika Baquir Block 13D 1 BS Life Sciences ZooLec ○ Phagocyte Activate T-cells ○ Cell mediated immunity T cell= type of WBC T cells and other immune Proteins on surface that system cells bind to antigens Destruction of T cells varies in response intracellular pathogens by ○ T cells activate B cells macrophages B cell = WBC Antibodies not involved Covered with antibodies ○ Humoral mediated immunity Antibodies = proteins B cells and production of that bind antigen to form antibodies antigen-antibody T cells help activate B complex cells Each b cell has different Antibodies coat shaped antigen pathogens making it Activated b cell divides easier for phagocytes to into plasma cells engulf them ○ Plasma cells make more antibodies to specific antigen The immune response for antigens can be Plasma cells = identical to memorized b cell Primary immune response = antigen enters Secretes loads of body for first time, it activates immune antibody specific to system antigen ○ Slow because not many B cells ○ Function of antibody that can make antibody needed to Coating of pathogen to bind it engulf it ○ Eventually, body produce enough Coating of pathogen to of right antibody to overcome prevent it from entering infection host cells ○ Infected person will show Binding to and symptoms neutralizing toxins ○ After being exposed to antigen, T produced by pathogen and B cells produce memory cells ○ Two types of specific immune ○ Memory cells = record specific response antibodies needed to bind antigen Cell mediated immunity Person now immune Humoral mediated Immune system has immunity ability to respond quickly to second infection What happens if same pathogen enters body again? ○ Secondary immune system = Immune system produce quicker strong immune response Memory B cells divide into plasma cells that produce right antibody to antigen Gets rid of pathogen before you begin to show any symptoms Ika Baquir Block 13D 1 BS Life Sciences ZooLec The primary immune response gives us immunity Act early against a disease, but only after you have become ○ Adaptive/specific immunity infected. The best way to prevent many infectious Defends against specific diseases caused by viruses and other pathogens is pathogen vaccination. ○ Vaccine = teaches immune Vaccines = protect individuals and system to recognize components populations against disease of pathogen bypassing primary ○ Contain antigen that cause body immune response to produce memory cells against pathogen ○ Antigens may be free or attached to dead pathogen ○ You become immune without symptoms Vaccines reduce occurrence of disease = unvaccinated also less likely to catch it Booster vaccines = make sure memory cells produced New knowledge about vaccines and antibodies validated by scientists ○ If there is epidemic or pandemic, rush in developing vaccine ○ Difficult decision on who is first to receive Summary Homeostasis = maintenance of stable internal condition ○ Regulation of body temp ○ Chemical composition of blood fluid and interstitial fluid Autonomic control system = regulate internal environment using negative feedback All autonomic control systems have 3 components supervised by hypothalamus ○ Receptor ○ Processing centers ○ Effectors Positive feedback = amplifies action Skin = helps regulate body temp, conserve moisture, protect body from pathogens, vitamin D production Hormones, antidiuretic hormones (ADH) and aldosterone = regulate kidney function Lymphatic system vessels = collect and distribute lymph fluid Immune system = protects body against pathogens and cancer cells WBCs = immune system Immune system has 2 divisions ○ Innate/nonspecific immunity