Nutrition and Digestion PDF

Systems Lesson 1 -​ Nutrition and digestion -​ All living things need essential nutrients to survive -​ Basic chemical building blocks -​ Six Essential nutrients -​ Macronutrients -​ Carbohydrates -​...

Systems Lesson 1 -​ Nutrition and digestion -​ All living things need essential nutrients to survive -​ Basic chemical building blocks -​ Six Essential nutrients -​ Macronutrients -​ Carbohydrates -​ Proteins -​ Fats -​ Water -​ Micronutrients -​ Vitamins -​ Minerals -​ Molecules found in food are too large and complex for cells to use them -​ Digestive system breaks the food into smaller molecules, used for energy -​ Macromolecules build and maintain cell structure and function -​ Carbohydrates -​ Composed of carbon, hydrogen, and oxygen atoms -​ Source of energy accessed very quickly -​ Carbs can be simple molecules, such as glucose, or more complex, such as starch -​ Simple Sugars are found in fruits (fructose) and milk (galactose) -​ Examples of monosaccharides (mono = 1, sacchar = sugar) -​ Basic unit of carbs, can’t be broken down any further -​ Monosaccharides combine to form disaccharides and polysaccharides -​ Disaccharides are a double sugar -​ Form when two simple sugars combine -​ Ex: Sucrose (glucose-fructose), Lactose (Galactose-glucose), Maltose (glucose-glucose) -​ Polysaccharides are more complex, made of many simple sugars combined -​ Plants make starch, and animals make glycogen. -​ Both are made of glucose subunits -​ Cellulose is made by plants; provides structural support -​ In humans, glucose gets converted into glycogen -​ Broken down into glucose when energy is needed -​ Fiber is made of cellulose, and is found in fruits, veggies, whole-grain breads etc., -​ Known as “roughage”; not completely digested, cleans out the gut and moves food and waste through the digestive system -​ Lipids (fats) -​ Essential source of energy and provides building materials for cell membranes and hormones  -​ Insulate the body from the cold, protects organs from injury, absorbs vitamins and conducts nerve impulses -​ Made of a glycerol backbone, attached to three fatty acid tails -​ Sources include nuts, grains, seeds, meat, eggs, cheese etc., -​ Three types -​ Saturated fats -​ Straight chain bond -​ Mostly found in meats -​ Unsaturated fats -​ Cis Double bond between 2 carbons -​ “Good” fats, mostly found in plants -​ Trans fats -​ Hydrogenated Trans double bond between 2 carbons -​ Partially saturated - unsaturated fats, not healthy -​ Proteins -​ Made up of amino acids -​ Joined together by peptide bonds -​ Form polypeptides -​ Antibodies, enzymes and hormones are proteins -​ Help build and repair muscle and cell membranes -​ Our cells cant make 9 of the amino acids from other molecules, known as the “Essential amino acids” -​ Sources of essential amino acids include meat, legumes, eggs, cheese, milk, whole grain products -​ Vitamins and Minerals -​ Minerals are inorganic compounds that the body needs in small amounts -​ Enable certain chemical reactions and help build bones -​ Don’t contain carbon, absorbed into bloodstream -​ Essential components of hemoglobin, hormones, enzymes, vitamins -​ Come from the earth -​ Vitamins are required in the body in small amounts, but they are crucial -​ Found in plants and animals -​ Serve as coenzymes, needed to make enzymes function -​ Involved in tissue development and growth -​ Helps the body fight and resists disease -​ Body produces vitamin D when exposed to sunlight -​ Vitamin K and some B vitamins produced by bacteria in the intestines -​ Only vitamins A and D can be stored in the body -​ The rest must be consumed regularly -​ Water -​ Makes up ⅔ of the body -​ Needed for proper functioning of cells and organs  -​ Roles include -​ Transporting nutrients into cells that line the small intestine -​ Flushing toxins from cells -​ Lubricating tissues and joints -​ Formin essential body fluids -​ Regulating body temp -​ Eliminating waste -​ Vital for maintaining body's fluid balance, -​ Amount lost = amount in -​ Constant supply of water is needed to replenish lost fluids -​ Digestive system -​ We obtain energy through cellular respiration -​ C6H12O6 + O2 = CO2 + H2O + ATP -​ Glucose reacts with oxygen to produce energy, CO2 and H2O -​ 40% of the energy is used for cellular function, while the other 60% maintains the body's temperature (thermal energy) -​ Calories -​ Calorie is the amount of energy required to raise the temp of 1g of water by 1 degree -​ Dietary calories represent 1000 small calories -​ Carbs, proteins and fats generate energy through cellular respiration -​ Fats are rich in energy (twice that of carbs) -​ Disease fighting foods -​ Nutraceutical -​ Substance purified from food and ingested like a medicine -​ Ex: omega-3 fish oil supplement -​ Functional Food -​ Food beyond the normal nutritional benefit of the food -​ Ex: fruits and vegetables that contain vitamins A,C,E and beta carotene -​ Probiotics -​ Contain substances that support health and strengthen body's natural defense -​ Intestinal bacteria makes us healthier -​ Antibiotics kill helpful bacteria along with bad bacteria -​ Probiotic products help add beneficial bacteria back into the large intestine Lesson 2 -​ Structure and Function of Digestive System -​ Used to break down foods into nutrients, which pass into the circulatory system and take where they’re needed -​ Food → Digestion → absorption → Waste Disposal -​ Absorption → Nutrients can be used for energy, or as building blocks for molecules in the cells -​ Invertebrate digestive systems -​ Gastrovascular cavity has a single opening (used for ingestion and excretion) -​ Alimentary canal has two openings, mouth and anus -​ Human gastrointestinal tract -​ Passageway that goes from the mouth to the anus -​ Around 7 - 9 m -​ Inside of the digestive tract is considered outside of the body -​ Four stages of food processing -​ Ingestion: taking in food -​ Digestion: breaking down food into nutrients -​ Absorption: taking in nutrients by cells -​ Elimination/Egestion: removing leftover wastes -​ Organs -​ Includes any organs that food and liquid travel through -​ Accessory organs play roles in the digestive process, like producing and storing substances -​ Digestive system -​ Begins when food enters the mouth -​ Physically broken down by the teeth (mechanical digestion) -​ Chemically broken down by amylase, an enzyme in saliva that breaks down carbs (chemical digestion) -​ Tongue moves the food until it forms a ball called a bolus -​ Bolus is passed down the pharynx -​ Epiglottis ensures the bolus doesn’t go into the trachea, and goes into the esophagus -​ Bolus passes down the esophagus via peristalsis -​ Wave of muscular contraction that push the bolus into the stomach -​ Movement and Control -​ Peristalsis -​ Push food along by smooth muscle contraction in walls of digestive system -​ Sphincters -​ Muscular ring like valves, regulate the passage of material between sections of the digestive system -​ Accessory glands -​ Salivary glands, pancreas, liver and gallbladder -​ Secrete digestive juices (enzymes & fluid) -​ Swallowing -​ Epiglottis  -​ Flap of cartilage that closes the trachea when swallowing, so the food goes down the esophagus -​ Esophagus -​ Food moves down it through peristalsis -​ Ingestion -​ Mouth -​ Mechanical digestion -​ Teeth break down food -​ Chemical digestion -​ Saliva releases: -​ Amylase -​ Enzyme which digests starches and carbs -​ Mucin -​ Mucus that protects the lining of the digestive system -​ Lubricates the food for easy swallowing -​ Buffers -​ Neutralizes an acid to prevent tooth decay -​ Antibacterial chemicals -​ Kill bacteria that enter the mouth -​ In order to enter the stomach, the bolus passes through the lower esophageal sphincter, a muscle that keeps stomach acid out of the esophagus -​ The stomach -​ Has folds called rugae -​ Muscular tissues -​ Moves the bolus (physical/mechanical digestions) and mixes gastric juice into it (chemical digestion) -​ Gastric juice -​ Mixture of stomach acid, mucus and enzymes -​ Acid kills off any bacteria or viruses -​ Enzymes help break down protein and fats(lipids) -​ Mucus protects the stomach lining from being eaten by the acid -​ Participates in absorption of nutrients -​ Some medicines, water and alcohol are absorbed through the stomach -​ Digested bolus is called chyme → leaves the stomach via the pyloric sphincter -​ Functions -​ Food storage: can fit ~2L of food  -​ Disinfect food -​ HCl = pH 2 -​ Kills bacteria -​ Breaks apart cells -​ Chemical digestion -​ Pepsin -​ Enzyme that breaks down proteins -​ Secreted as pepsinogen -​ Activated by HCl -​ Chyme then enters the small intestine -​ Most absorption happens here -​ Liver and pancreas help the small intestine -​ Small intestine contains three parts -​ Duodenum -​ Bile, produced in the liver, stored in the gallbladder, enters through the bile duct -​ Breaks down fats -​ Pancreas secreted pancreatic juice to reduce the pH of chyme -​ Jejunum -​ Majority of absorption -​ Lined with villi, increasing the surface area for absorption of nutrients -​ Each villi contains microvilli, increasing the surface area -​ Each villus contains blood vessels and lymph vessels -​ Fatty acids and glycerol are transported into lymph vessels -​ Sugars and amino acids are absorbed into the bloodstream through blood vessels -​ Absorption: -​ Glucose -​ Absorbed by active transport -​ Fructose -​ Absorbed by passive transport -​ Amino acids -​ Absorbed by active transport -​ All are transported through the epithelial cell of the intestine to capillaries to the portal vein of the liver -​ Role of the liver  -​ Blood from the small intestine travels to the liver, where nutrients are used to build molecules -​ Molecules are modified and cleaned before going to the heart -​ Ileum -​ Last portion of the small intestine -​ Has fewer villi -​ Compacts the leftovers to pass through the caecum and into the large intestine -​ Large Intestine -​ Used to absorb water from the waste leftover -​ Produce vitamin K and some B vitamins -​ All leftover waste is compacted and stored in the rectum -​ When full, anal sphincter loosens and waste passes out through the anus -​ Pancreas -​ Digestive enzymes -​ Peptidases -​ Trypsin -​ Trypsinogen -​ Chymotrypsin -​ Chymotrypsinogen -​ Carboxypeptidase -​ Procarboxypeptidase -​ Pancreatic amylase -​ Buffers -​ Reduce acidity -​ Alkaline solution that contains bicarbonate -​ Liver -​ Produces bile -​ Stored in the gallbladder -​ Enters through the bile duct -​ Emulsifies fats (breaks down large drops into smaller ones) -​ Contains colors from old red blood cells collected in the liver -​ Iron in the RBC rusts and turns feces brown -​ Appendix -​ Located in the caecum -​ Links the small intestine to the large intestine  -​ Thought to be vestigial -​ Role in supporting the immune system -​ Safe harbour of good bacteria during gastrointestinal distress -​ Mesentery -​ Suspends the stomach and intestines to the abdominal cavity -​ Supplies the intestine with blood vessels to deliver oxygen and carry nutrients to the body -​ Supplies the intestine with nerves and lymph vessels Lesson 3 -​ Circulatory System -​ Transports gases, nutrients and waste -​ Regulates internal body temp and transport chemicals -​ Protect against blood loss -​ Blood -​ Circulates through the body delivering nutrients and removing waste -​ Made up of: -​ Red blood cells -​ White blood cells -​ Platelets -​ Suspended in plasma -​ Plasma -​ Makes up 55% of your blood -​ Made up of proteins, minerals, dissolved salts, and water -​ Red Blood Cells -​ Body produces two million red blood cells every second -​ Responsible for carrying oxygen to you lungs, and carrying carbon dioxide from your cells to your lungs -​ Contains hemoglobin -​ Protein that binds oxygen in the lungs and releases it through the body -​ Also binds CO2, removing it from the cells -​ Also known as erythrocytes (red hollow), -​ Get their red colour from the iron in hemoglobin, where oxygen binds -​ White blood cells -​ Aka leukocytes -​ Defend the body against foreign organisms, such as bacteria and viruses -​ Form antibodies, protecting the body from future attacks -​ Make up 1% of blood volume, but can increase when the body is fighting an infection  -​ Phagocytes attack pathogens, and destroy them via phagocytosis -​ 5 main types -​ Neutrophils -​ Most abundant -​ Found in body tissue and blood -​ Eosinophils -​ Found in mucus lining of digestive and respiratory tracts -​ Basophils -​ Secrete substances that attract phagocytes to destroy pathogens -​ Lymphocytes -​ Produce antibodies that incapacitate pathogens making them easily detectable and destroyable -​ Monocytes -​ Circulate in the bloodstream for a few days before specializing as macrophages which destroy bacteria -​ Platelets -​ Contains enzymes needed to turn clotting factors into fibrin, which heals wounds -​ Collect around the edges of a wound and break themselves open -​ Release enzymes that chemically react to help heal the wound -​ Aka thrombocytes -​ Blood vessels -​ Three types -​ Arteries -​ Carry blood away from the heart -​ muscular walls -​ Heart contracts, gush of blood is sent out under high pressure -​ Artery wall expands and balloons out -​ Arteries are thicker than veins and are deeper in our body -​ Arterial blood is under pressure, if a large artery is cut blood will spurt out in gushes -​ Veins -​ Blood vessels that carry blood toward the heart -​ Don’t have muscles, but have valves -​ Blood doesn't spurt from a vein, making clotting easier -​ -+  -​ Capillaries -​ Tiny blood vessels that join arteries to veins -​ Walls are max one cell thick -​ Nutrients and gases diffuse into the cells through the walls of capillaries -​ Waste diffuses from the cells to the capillaries -​ The Heart -​ A muscle that contracts and expands -​ Made up of four chambers -​ Left and right atria (sing. atrium) -​ Left and right ventricles -​ Atria are smaller than the ventricles → they don’t work as hard -​ Left ventricle is the strongest of the heart’s chambers -​ Each atrium is separated from the ventricle by a valve (atrioventricular valve) -​ Right atrium and right ventricle -​ Separated by the tricuspid valve -​ Made up of two flaps -​ Left atrium and ventricle -​ Separated by the bicuspid valve (or mitral valve) -​ Made up of two flaps -​ Other flaps are called semilunar valves due to their half-moon shape -​ The Lymphatic System -​ Network of vessels, nodes, and organs -​ Collects fluid that leaves capillaries and looks for any micro organisms -​ Releases lymphocytes to kill any diseases -​ Maintains fluid balance by collecting excess fluid and putting it back into the bloodstream -​ Fluid collected is called lymph -​ Clear watery fluid made of proteins, salt, glucose and other things -​ As blood circulates some leaks into tissues -​ Portion that escapes is called interstitial fluid -​ Most seeps back into the bloodstream, some is left behind -​ Lymphatic system removes this fluid and returns them into the bloodstream, preventing a fluid imbalance → edema (swelling) -​ Circuits of blood flow -​ Pulmonary circuit -​ Blood to lungs -​ Systemic circuit -​ Blood to body -​ Coronary circuit -​ Heart to heart -​ Supplies heart muscle with oxygen and nutrients  -​ Heartbeat -​ Heart is made of cardiac muscle -​ Muscle is myogenic, naturally contracts and relaxes -​ Receives no impulse from a nerve to make it contract -​ Initiated by the Sinoatrial node (SAN) or pacemaker -​ Sets the rhythm for all cardiac muscle -​ Pacemaker cells have a built in rhythm which is faster than the other cells in the heart -​ Sends out a wave of electrical activity to the atrial walls -​ Cardiac muscle responds by contracting at the same speed as the SAN -​ Causes both atria contract simultaneously -​ Delay between atrial contraction and ventricular contraction -​ Fibres between the two chambers that don't conduct the impulse cause the delay -​ Therefore, wave is conducted through fibres in the septum known as the atrio-ventricular node (AVN) -​ After 0.1 seconds the AV node passes the signal onto another set of fibres call the AV bundle (runs down the septum), which transmits it to the Purkinje fibres causing the ventricles to relax -​ Fibrillation is the result of the contractions becoming out of sync -​ Electric shock treatment restarts the SA node​ Lesson 4 -​ Respiration refers to all processes that supply oxygen to body cells and gets rid of carbon dioxide from the body -​ Respiration is divided into -​ Breatinhg: Air in and out of the lungs -​ External respiration: o2 and co2 exchanged between the air and blood -​ Internal respiration: exchanging of o2 and the tissue in the body -​ Cellular respiration: using oxygen to get the energy from glucose, producing co2 as a waste product -​ Tracing air -​ UPPER RESPIRATORY TRACT -​ Air enters through the nostrils -​ Nostrils warms and adds mosisture to the air -​ Catches any dust and particles -​ Passes through the phayrnx whch connects the mouth and nasal cavity -​ Passes by the glottis (opening of the trachea) -​ Epiglottis prevents food from entering the trachea -​ Passes through the larynx (voicebox) -​ Pases through when you exhale as well -​ Loose chords produce low sound -​ Right chords produce high sound -​ Goes down the trachea -​ Cartilage rings line the trachea to prevent it from collapsing  -​ Cilia line the tract to capture any particles (dust, bacteria) -​ Propels them back to the nose and throat (sneeze/cough) -​ LOWER RESPIRATORY TRACT -​ Trachea branches into 2 bronchi -​ Bronchus subdivides into smaller bronchioles -​ Each bronchiole ends in a cluster of tiny sacs called alveoli -​ Wall of each alveoli is one cell thick, and adjacent to small capillaries -​ Capillaries and alveolus are the area where gas exchange takes place -​ -​ Inhalation -​ Intercostal muscles contract, lifting up the rib cage, and outwards -​ Diaphragm contracts and pulls downward, as the lungs expand air moves in -​ Thoracic cavity is airtight, increasing the volume produces a increase in air pressure, are then enters the lungs (diffusion) -​ Exhalation -​ Intercostal muscles relax, rib cage returns to a normal position -​ Diaphragm moves upward, as the lungs contract air moves out -​ Composition of Air -​ Inhaled oxygen dissolves into the fluid lining the alveoli -​ Normally, the oxygen concentration in the air is greater than in the blood, causing the oxygen to move into the bloodstream through diffusion -​ Opposite is true for CO2 -​ Air is composed of -​ Oxygen -​ Carbon Dioxide -​ Nitrogen -​ Water vapor -​ key words -​ Lung capacity: volume of air in lungs at maximum inspiration -​ Tidal volume: volume of air inhaled and exhaled at normal breath -​ Inspiratory reserve volume: Additional volume of air that can be taken in past tidal volume -​ Expiratory reserve volume: additional volume of air that can be forced out of the lungs beyond tidal exhalation -​ Vital capacity: total volume of gas that can be moved in or out of the lungs -​ Residual volume: Leftover gas in lungs after full exhalation (so lungs don’t collapse) -​ Lung disorders -​ Cystic Fibrosis -​ Fatal genetic disease where thick mucus blocks the airways -​ Traps bacteria in the lungs leading to infection and damaged lung tissue -​ Affects several systems including respiratory and digestive -​ Physical therapy is a treatment; no cure -​ SARS -​ Severe Acute Respiratory Syndrome -​ Pneumonia-like respiratory disease -​ Causes inflammation of the lungs, fever and a cough -​ Breathing becomes difficult -​ Lung Cancer -​ Cells in the lungs start to grow too fast and clump together -​ Form tumours -​ Surgery is an option, as well as drugs and radiation