Ch. 39-40 Digestive, Excretory and Immune Systems

Ch. 39-40 Digestive, Excretory and Immune Systems By: Brianna Shields June 3, 2006

GOAL • Identify five nutrients found in foods • Relate the role of carbohydrates, proteins, lipids, vitamins, minerals and water in maintaining a healthy body • Describe each of the parts of the USDA food guide pyramid • Name one health disorder associated with high levels of saturated fats in the diet • Relate the four major functions of the digestive system to the processing of food • Summarize the path of food through the digestive system • Identify the major wastes produced by humans • Describe the path of urine through the urinary system • Describe how skin and mucous membranes defend the body • Compare the inflammatory response with the temperature response

GOAL • Identify proteins that kill or inhibit pathogens • Analyze the roles of white blood cells in combating pathogens • List four kinds of immune system cells and describe their functions • Describe how white blood cells recognize pathogens • Identify the role of helper T cells in the immune response • Compare the role of T cells with B cells in the immune response • List five ways diseases can be transmitted to humans • Analyze how the body produces immunity to pathogens • Describe how vaccines produce immunity to pathogens • Describe several autoimmune diseases • Summarize how HIV disables the immune system

FOOD Amount of energy body needs depends on Age Sex Rate of growth Level of physical activity Nutrients- substance required by the body for energy, growth, repair and maintenance Carbohydrates Lipids Proteins Vitamins Minerals DIGESTIVE SYSTEM

Digestion Digestion- breaking down food into molecules the body can use (to make ATP during cellular respiration) Calorie- energy available in food Amount of heat required to raise temperature of 1 g of water 1 degree celsius DIGESTIVE SYSTEM

Carbohydrates Must be broken down into simple sugars to be used by cells Glucose Found in fruits, honey, onions Directly absorbed into blood, used by cells Starches- long chains of sugars Cereal grains, vegetables Cellulose- plant cell wall substance No energy for humans, can’t digest it (helps stimulate mucus production to slide food along) Excess carbohydrates Stored as glycogen in liver, to be broken down into glucose later Excess glucose converted to fat DIGESTIVE SYSTEM

Proteins Proteins- amino acids within are used by body to make other proteins, enzymes and antibodies 20 amino acids needed by body 10 can be made from other amino acids 10 essential amino acids must come from animal products (egg, milk, meat) or eating several types of plants Extra protein in body, converted to fat DIGESTIVE SYSTEM

Lipids Lipids- insoluble, organic compounds Fats that store energy Pad and insulate organs Solvents for fat soluble vitamins Too much saturated fat linked to high blood cholesterol levels Limit consumption of saturated fats DIGESTIVE SYSTEM

Balancing Nutrients and Energy Excess calories stored as body fat or glycogen = gaining weight Use more calories than you take in= lose weight Obesity = more than 20% heavier than ideal weight Risk of diabetes, heart disease, osteoarthritis Regular physical exercise needed to maintain balance DIGESTIVE SYSTEM

Vitamins Vitamins- organic substances in small amounts in food Need trace amounts for normal metabolic functioning Dissolve in water or fat Stored in fat = A, D, E and K Too much vitamin A and D can be deadly Extra water soluble vitamins (C and B) are excreted in urine and must be replaced by diet DIGESTIVE SYSTEM

Minerals Minerals- naturally occurring, inorganic substances Used to make body structures and substances Essential to nerve and muscle function (Mg, Ca, Na, K, Zn) Needed to maintain osmotic balance Aids in enzyme functioning Required by teeth and bones (Ca and P) Fe needed for transporting oxygen Must be replaced daily, because they’re soluble in water DIGESTIVE SYSTEM

Water Transports gases, nutrients, waste products Regulates body temperature 2/3 body weight = water DIGESTIVE SYSTEM

ASSESSMENT (use notesheet) • Predict four nutrients that would be found in a serving of green beans • Compare the functions of carbohydrates and proteins in maintaining a healthy body • Describe the type of information the USDA food guide pyramid provides • Evaluate the roles vitamins, minerals and water play in maintaining a healthy body

PATH OF FOOD Mouth Teeth chew food into shreds (mechanical digestion) Saliva moistens and lubricates food Amylases breakdown starches and simple sugars (chemical digestion) Pharynx (throat) Food swallowed Epiglottis moves to cover the trachea Esophagus No digestion, food simply descends to stomach Food pushed by peristalsis (waves of muscle contractions) DIGESTIVE SYSTEM

PATH OF FOOD Stomach Food enters stomach through sphincter (blocks acidic food from rising back up) Stores food Mechanically mushes food with peristaltic waves Chemically digests proteins with gastric juice (hydrochloric acid and pepsin) Food spends 2-6 hours here DIGESTIVE SYSTEM

PATH OF FOOD Small Intestine Food enters through a sphincter Long, coiled tubular organ with a small diameter Food mixed by peristalis Duodenum- first part, receives secretions from pancreas, liver, gallbladder Cells in lining of S.I. secreted enzymes to complete digestion Carbohydrates  monosaccharides Proteins  amino acids Lipids  fatty acids DIGESTIVE SYSTEM

PATH OF FOOD Small Intestine Bile produced from liver and stored in gall bladder is secreted, breaks fats into droplets Absorption of nutrients occurs Fingerlike villi in lining of S.I. increase surface area for absorption Sugar and amino acids enter villi capillaries DIGESTIVE SYSTEM

PATH OF FOOD Large Intestine (colon) Short in length, large in diameter No digestion, only temporary waste storage 5-10% of food is waste (90-95% absorbed by body) Mineral ions and water absorbed through walls Mostly contains dead cells, mucus, digestive secretions, bacteria and yeast DIGESTIVE SYSTEM

PATH OF FOOD Large Intestine (colon) Bacteria in colon make vitamin K and vitamin B for your body Bacteria transform and compact wastes into feces Peristalsis passes solids into rectum, and out anus Takes 12 to 24 hours for waste to exit Diarrhea- food and water pass through too quickly Constipation- food sits there too long and too much water is absorbed DIGESTIVE SYSTEM

PATH OF FOOD Liver (upper right abdominal cavity) Secretes bile for fat emulsification and absorption of fat soluble vitamins Increased bile in blood= jaundice (yellow skin) Converts extra sugar in blood to glycogen, and modifies amino acids Detoxifies poisons- but, heavy metals and pesticides accumulate there Drug and alcohol use damage it- causes liver scarring called cirrhosis DIGESTIVE SYSTEM

ASSESSMENT (use notesheet) • Summarize the path a piece of cheese pizza would follow through the digestive system • Relate the role of the mouth, stomach, small intestine, and large intestine in the digestion of a piece of cheese pizza. • Locate the area of the digestive system where nutrients are absorbed into the blood stream • State how the liver and pancreas are involved in digestion • A person has a small intestine that has villi but a reduced number of microvilli. Would you expect this person to be underweight or overweight? Explain.

Excretory System Excretion- rids the body of wastes such as toxic chemicals, excess water, salts, and carbon dioxide while maintaining osmotic and pH balance Lungs- excrete CO2 and H20 Skin- excretes water (sweat) and salt Liver- ammonia converted to urea, transported and removed from blood by kidneys EXCRETORY SYSTEM

Excretory System Kidneys- excrete water (urine) Regulates amount of water and salt in blood plasma Bean shaped organs in lower back Consists of 1 million nephrons (tiny tubes surrounded by capillaries) Filtration – water, salts and urea exit capillaries and enter Bowman’s capsule Reabsorption- filtrate passes through renal tubes, useful glucose, ions and water are removed from the filtrate and reenter bloodstream through capillaries Secretion – water, urea and salt leftover form urine that enter ureters leading from kidney to urinary bladder EXCRETORY SYSTEM

Excretory System Urine elimination Muscle contractions in ureters, move urine along Urine fills urinary bladder (sac expands) Bladder contracts to force urine out of body through urethra (urination) EXCRETORY SYSTEM

Excretory System Kidney Damage Can be life threatening because of vital role in maintaining homeostasis Usually due to diabetes, high blood pressure or immune system damage Kidneys often exposed to hazardous chemicals (paint, varnish, aerosol sprays, lead) Kidney failure causes urea to accumulate in plasma EXCRETORY SYSTEM

Excretory System Kidney Damage Kidney Dialysis Machine filters your blood temporarily Kidney Transplant Replace kidney with that from a donor Recipient’s immune system may reject it (if it sees antigens on surface of organ as “foreign”) EXCRETORY SYSTEM

ASSESSMENT (use notesheet) • Identify how the carbon dioxide in your body is produced and excreted • Relate the following terms to the formation of urine: filtration, reabsorption and secretion • Name the liquid stored inside the collecting duct of a nephron • Summarize how urine is stored and eliminated from the body • A doctor has just informed a patient that his urine contains a high sugar concentration. Explain why this may indicate damaged kidneys

Immune System Pathogen- disease causing agent Immune system- cells and tissues that detect and destroy pathogens, preventing or reducing the severity of infection IMMUNE SYSTEM

FIRST LINE OF DEFENSE Doesn’t target specific pathogens Skin- barrier to invading pathogens Oil and sweat make skin acidic, inhibiting pathogen growth Mucous Membranes- epithelial tissue coating in sticky mucus, barrier to pathogens Digestive system, Nasal passages, Lungs, Respiratory passage, Reproductive tract IMMUNE SYSTEM

SECOND LINE OF NONSPECIFIC DEFENSE Necessary when pathogens bypass the first line and reach deeper tissue Inflammatory Response Stimulated by injury or infection Cells near injury release histamine to increase blood flow WBC’s attack pathogens at infection site Swelling, redness and pus accumulate (contains WBC’s, dead cells and dead pathogens) IMMUNE SYSTEM

SECOND LINE OF NONSPECIFIC DEFENSE Temperature Response Increase in body temperature (fever) to prohibit disease causing bacteria from growing Temps over 103 F are dangerous Temps over 105 F are fatal IMMUNE SYSTEM

SECOND LINE OF NONSPECIFIC DEFENSE Proteins Complement System Proteins wander in blood, attack pathogens with ringlike MAC structure, punching a hole in the pathogen causing it to leak and die Interferon- released by virus infected cells to stop viruses from making proteins and RNA in other cells IMMUNE SYSTEM

SECOND LINE OF NONSPECIFIC DEFENSE White Blood Cells (patrol blood stream, wait in tissue for pathogens to kill) Neutrophils- engulf and destroy bacterial pathogens (kill themselves in the process) Macrophages- ingest and kill pathogens, clear dead cells and debris (many found in spleen and lungs) Natural Killer Cells- large, attacks cell infected by pathogens (punctures cell causing water to rush in and burst the cell)- can attack and kill cancer cells IMMUNE SYSTEM

ASSESSMENT (use notesheet) • Describe how the inflammatory and temperature responses help defend against infection • Identify the role of white blood cells in the second line of nonspecific defenses • Explain why a drug that reduces fever might delay rather than speed up your recovery from an infection

BODY’S THIRD LINE OF DEFENSE: Immune Response Cells Involved (all types of White Blood Cells) Wbc’s produced in bone marrow and circulate through blood and lymph Macrophages- consume pathogens and infected cells Cytotoxic T cells- attack and kill infected cells B Cells- label invaders for later destruction by macrophages Helper T cells- activate cytotoxic T and B cells IMMUNE SYSTEM

BODY’S THIRD LINE OF DEFENSE: Immune Response Infected body cells have ANTIGENS on their surface Antigens- substance that triggers immune response (made up of proteins and parts of pathogen cells) WBC’s recognize and bind to antigens that match their shape (lock and key fit) IMMUNE SYSTEM

Immune Response Pathway 1. Cells infected by virus, display antigens on surface 2. Macrophages engulf viruses, and display the viral antigens on their surface 3. Helper T cells bind to viral antigen on macrophages 4. Macrophages release interleukin-1 protein 5. Interleukin 1- activates helper T cells 6. Helper T cells activate cytotoxic T cells and B cells, and release interleukin 2 stimulating division of all T cells and B cells IMMUNE SYSTEM

Immune Response Pathway 7. B cells divide and develop into plasma cells 8. Plasma cells divide and make antibodies (y shaped defensive protein produced when exposed to an antigen, which can bind to that antigen) 9. Antibodies enter bloodstream, attach to viral antigens marking virus for destruction 10. Antibody/viral antigen clumps easily recognized and destroyed by macrophages 11. Cytotoxic T cells puncture infected cell membranes, killing them (recognize the antigens on surface) IMMUNE SYSTEM

ASSESSMENT (use notesheet) • List the different kinds of white blood cells involved in the immune response • Describe how white blood cells recognized and bind to pathogens • Compare the roles of B cells and T cells in the immune response • Explain the role of helper T cells in the immune response • How would an enzyme that destroys interleukins affect the immune response? • Summarize the immune response by listing the steps and drawing a picture

Disease Transmission Disease can be transmitted through Person to person contact- ex: sex, kissing or handshaking Air Food Water Animal bites IMMUNE SYSTEM

Disease Transmission Detecting disease- Koch’s Postulates Pathogen must be found in an animal with the disease Isolate pathogen from sick animal, grow in lab When isolated pathogen is injected into healthy animal, animal must develop disease Take pathogen from second animal, grow in lab, pathogen should be same as original pathogen IMMUNE SYSTEM

Disease Transmission Long Term Protection After immune response some B and T cells become memory cells that continue to patrol body tissues Some provide lifelong protection If pathogen reappears, memory cells activate antibody production against pathogen Macrophages destroy pathogen before you become ill You are “immune” or resistant to the disease IMMUNE SYSTEM

RESISTANCE TO DISEASE (IMMUNITY) Individuals who recover from an infectious disease, develop immunity to that disease Vaccination- medical procedure used to produce immunity Vaccine- solution of dead or modified pathogen that can no longer cause disease Triggers immune response, with no symptoms of infection System develops antibodies and memory cells Ex: Smallpox, measles, polio, tetanus, diphtheria Antigen Shifting- virus produces new antigens not recognized by immune system (ex: flu virus, since it mutates repeatedly over time) IMMUNE SYSTEM

ASSESSMENT (use notesheet) • List two ways that diseases can be transmitted between people • Summarize Koch’s postulates for identifying specific pathogens • Describe how vaccination produces immunity • Explain why you cannot get many diseases more than once

AUTOIMMUNE DISEASES The body launches an immune response against its own cells as if they were pathogens Can’t distinguish between “self” and “nonself” antigens Multiple Sclerosis- immune system destroys insulating material around nerve cells of the brain, spinal cord and eye Leads to vision, speech and coordination problems IMMUNE SYSTEM

AUTOIMMUNE DISEASES HIV- human immunodeficiency virus that causes AIDS HIV recognizes CD4 receptor proteins on some human cells, and enters WBC’s by binding to CD4 Invades Helper T cells- they die and immune system weakens and becomes overrun by pathogens it would normally detect and destroy Results in susceptibility to other diseases (opportunistic infections) IMMUNE SYSTEM

AUTOIMMUNE DISEASES HIV Testing Check for HIV antibodies in blood = HIV positive Check for T cell count HIV may be symptom free May take 10 years or longer to progress to AIDS IMMUNE SYSTEM

AUTOIMMUNE DISEASES HIV Transmission Sexual contact (risk reduced by using a condom) Passed between drug users sharing needles From pregnant mother to baby Nursing mothers to baby through breastmilk IMMUNE SYSTEM

AUTOIMMUNE DISEASES Allergic Reactions Allergy- body’s inappropriate response to normally harmless antigens Symptoms usually uncomfortable (runny nose, itchy eyes, sneezing, congestion) Common allergens: dust mites, fungus, pollen Most meds contain antihistamines Most severe allergic rx = asthma, which can be life threatening IMMUNE SYSTEM

Ch. 39-40 Digestive, Excretory and Immune Systems