Animal Systems PDF

Animal Systems Lesson #1​ Key Concepts: -​ Food contains the nutrients that we need for energy and growth -​ A balanced diet provides fuel and building materials and promotes good health -​ You must process foods in your digestive system in order to use the nutrient...

Animal Systems Lesson #1​ Key Concepts: -​ Food contains the nutrients that we need for energy and growth -​ A balanced diet provides fuel and building materials and promotes good health -​ You must process foods in your digestive system in order to use the nutrients effectively - Food processing occurs in 4 stages Nutrients: -​ All living things must obtain nutrients (basic chemical building blocks) -​ There are 6 essential nutrients and they are organized under “macronutrients” (body needs greater amounts) or “micronutrients” (body needs smaller amounts) Macronutrients: Micronutrients: Carbohydrates Vitamins Protein Minerals Fat Water Processing Molecules: -​ The molecules found in your body are too large and complex to be used by the cells, which is why the digestive system breaks down food into smaller molecules that cells use for energy -​ Macromolecules are used to build and maintain cell structure and function Carbohydrates: -​ Carbohydrates are composed atoms of carbon, hydrogen and oxygen -​ Carbohydrates can be simple molecules like glucose, or more complex ones such as starch -​ Simple sugars are found in foods like fruits (fructose) and milk (galactose) -​ Glucose, fructose and galactose are all examples of monosaccharides(mono = 1, sacchar = sugar) -​ Monosaccharides are the basic unit of carbohydrates and cannot be broken down into simpler compounds -​ They combine chemically to form disaccharides and polysaccharides Disaccharides: Polysaccharides: - Disaccharides are a “double sugar” and form when - Polysaccharides are more complex carbohydrates 1 two monosaccharides (sugars) combine composed of many simple sugars linked together - Ex: Sucrose, Maltose and Lactose (poly = many) - Ex: Plants make starch and animals make glycogen. Both are made from glucose and store energy -​ In humans, glucose is converted into glycogen in the liver. It is broken down into glucose when energy levels are in high demand -​ Fiber is made of cellulose and can be found in fruits, vegetables, whole grains and bread. -​ Fibre is also known as “roughage” because it is not completely digestible, it acts like a scrub, cleaning out your gut and helping food get through the digestive system Lipids (fats): -​ Lipids are essential as both a source of energy and to provide building materials for cell membranes and hormones -​ Lipids are made of a glycerol backbone attached to 3 acid tails -​ The three types of fats are: saturated fats, unsaturated fats and trans fats Proteins: -​ Proteins consist of subunits called amino acids -​ These amino acids are joined together by peptide bonds to form long chains called polypeptides -​ Antibodies, many enzymes and hormones are proteins. Proteins help build and repair muscle and cell membrane -​ Human cells cannot make 9 of the amino acids from other molecules. These are known as “essential amino acids” Vitamins and Minerals: -​ Minerals are inorganic compounds that the body needs in small amounts -​ Minerals enable certain chemical reactions and help build bone and cartilage -​ They do not contain carbon, and are readily absorbed into the bloodstream -​ Minerals are essential components of hemoglobin, hormones, enzymes and vitamins -​ They serve as coenzymes, chemicals needed to make enzymes function -​ The body can produce vitamin D when exposed to sunlight, while vitamin K and some B vitamins are produced by bacteria in the intestines -​ Only vitamins A and D can, 2 of the 4 fat-soluble vitamins can be stored in the body Water: -​ Water makes up about two-thirds of the body’s mass and is needed for the proper functioning of all cells and organisms, its many roles include:​ Transporting dissolved nutrients into the cell that lines the small intestine 2 Flushing Toxins from cells Lubricating tissue and joints Forming essential body fluids such as blood and mucus Regulating body temperature (sweating) Eliminating waste materials (urine and sweat) The average adult produces 1.5L of urine a day and loses about 1L of water through the breath, perspiration and bowel Food as Fuel: -​ We obtain the energy from the food we eat through cellular respiration -​ Glucose reacts with oxygen to produce energy CO2 and H2O -​ 40% of this energy is used for cellular function while the other 60% is converted into thermal energy Calories: -​ A calorie is the amount of energy needed to raise the temperature of 1g of water by 1℃ -​ Dietary calories © represent 1000 calories -​ Carbohydrates, proteins and fats can generate energy through cellular respiration -​ Fats are rich in energy, containing more than twice the energy of carbohydrates per gram (9C/g and 4C/g respectively) -​ We require the minimum number of calories every day to perform the basic functions of life Foods that may Fight Disease -​ A nutraceutical is a substance that is purified from foods and taken like a medicine to provide health benefits including disease prevention, for example omega 3 fish oil supplements -​ A functional food is a food that has health benefits, including disease prevention that are beyond the normal nutritional benefit for food Probiotics -​ Probiotics contain substances that support health and may help to strengthen the body’s natural defense system -​ Intestinal Bacteria make us healthier -​ Probiotic products, such as probiotic yogurt, help to add beneficial bacteria back into the large intestine 3 Lesson #2 Digestion System: -​ The digestive system is used to break down food into nutrients which then pass into the circulatory system and are taken throughout the body -​ There are 4 stages to food processing Ingestion Taking in food DIgestion Breaking down food into nutrients Absorption Taking in nutrients by cells Egestion Removing any leftover waste -​ The gastrointestinal tract includes any organs that food and liquid travel through -​ The accessory organs play key roles in the digestive process, like producing and storing substances 4 The mouth and esophagus: -​ The digestive process starts once food first enters the mouth -​ There are two ways the mouth breaks down food:​ Mechanical Digestion Chemical Digestion - When food enters the mouth, teeth break up - Saliva (produced by your salivary glands) and mucin the food by chewing, causing mechanical (mucus) protects soft lying of your teeth and the digestive digestion system, while lubricating your food for easier swallowing - tongue moving food around the mouth - Amylase: enzyme that breaks down food (starch) - buffers: neutralize acid to prevent tooth decay -​ Once your food is broken down, your tongue moves food around until it forms a wet ball called a bolus -​ The bolus is then passed down to the pharynx (throat) -​ The epiglottis is a flap of cartilage that closes and opens the trachea (windpipe), and makes sure that the bolus is passed down the esophagus and NOT the trachea -​ Once the bolus enters the esophagus, peristalsis (a wave of muscular contractions in the esophagus that push the bolus towards the stomach) occurs Stomach: -​ Antibacterial chemicals: kill bacteria that enter mouth with food -​ To enter the stomach, the bolus must be passed down through the lower esophageal sphincter (a tight muscle that keeps stomach acid out of the esophagus) -​ There are two types of ways the stomach breaks down food: Physical Digestion Chemical Digestion - The stomach has a fold called rugae, and is a - Mixes it with gastric juice, a mixture of stomach acid, big muscular pouch that churns the bolus mucus and enzymes, this acid kills off any bacteria - The enzymes help break down proteins and lipids -​ The mucus protects the lining of the stomach from being decayed by the acid -​ The digested bolus is now called chyme, and it leaves the stomach by being passed through the pyloric sphincter Small Intestine: -​ The chyme is now in the small intestine -​ The majority of absorption happens in the small intestine -​ The small intestine is broken down into three parts: Duodenum Jejunum Ileum 5 - Bile, produced in the liver but - The jejunum is where the - The last portion of the small stored in the gallbladder, enters majority of absorption takes place. intestine is the Ileum which has through the bile duct. It emulsifies It has tiny fingerlike projections fewer villi and basically compacts fats and neutralizes chyme called villi lining it, which increase the leftovers to pass through the - The pancreas secretes pancreatic the surface area for absorbing caecum into the large intestine. juice which contain enzymes to nutrients. digest carbohydrates, proteins and - Each villi has tiny fingerlike fats projections called microvilli, further increasing the area of absorption Absorption: -​ Each villus contains a network of blood vessels and lymph vessels (carry fluids away from cells). Fatty acids and glycerol recombined and transported into lymph vessels. Sugars and amino acids are absorbed into the bloodstream through blood vessels -​ Glucose: Absorbed via active transport -​ Fructose: Absorbed via passive transport (no energy required) -​ Amino acids: Absorbed via active transport -​ All of the above: transported through the epithelial cell off the intestine to capillaries to the portal vein to the liver -​ Molecules are modified and detoxified before traveling to the heart for distribution to the rest of the body via circulatory system Pancreas: -​ Digestive enzymes:​ - peptidases (trypsin)​ - trypsinogen (chymotrypsin)​ - chymotrypsinogen (carboxypeptidase)​ - procarboxypeptidase (pancreatic amylase) -​ Buffers (reduces acidity) Liver: -​ Bile, which is produced in the liver and stored in the gallbladder, enters through the bile duct. -​ Bile emulsifies fats (i.e. breaks down large drops into smaller ones) to increase surface area for digestion Appendix: -​ The appendix is a small pouch located at the beginning of the large intestine (called the caecum) -​ It was thought to be vestigial, but now is understood to have at least two functions:​ - Roles in supporting the immune system​ - Provides a safe harbor of good bacteria during gastrointestinal distress -​ Appendicitis occurs when the appendix becomes infected with trapped bacteria 6 Large Intestine, Rectum and Anus: -​ The large intestine is used to absorb water from the waste material left over and to produce vitamin K and some B vitamins using the helpful bacteria that live there -​ All leftover waste is compacted and stored at the end of the large intestine called the rectum -​ When full, the anal sphincter loosens the waste (feces), and passes out the body through the anus Mesentery: -​ The mesentery (A folded membrane) has several essential functions: - Suspends the stomach and intestines to the abdominal cavity - supplies intestines with blood vessels to deliver oxygen and carry nutrients to the body - supplies intestines with nerves and lymph vessels Digestion and Homeostasis: -​ The endocrine, nervous, digestive and circulatory systems all work together to control digestion -​ Before we eat, smelling food releases saliva into our mouths and a hormone called gastrin in our stomachs which prepares the body for a snack by releasing gastric acid -​ A larger meal activates receptors that churn the stomach and empty it faster. If the meal was high in fat, digestion is slowed, allowing time for the fat to be broken down, hence why we feel dull after eating a high fat meal Lesson #3 Structure and Function of the Circulatory System: -​ Structures of the circulatory system include blood vessels, blood, and the heart. They work together to transport substances that are vital to health -​ The blood contains useful substances and cellular waste -​ The lymphatic system is a transport system that recycles fluids needed in the circulatory system Key Functions of the Circulatory System: 1)​ Transport gases (from the respiratory system), nutrient molecules, and waste materials (from the digestive system) 2)​ Regulate internal temperature and transport chemical substances that are vital to health from one part of the body to the other 3)​ Protect against blood loss from injury and against disease-causing microbes or toxic substances introduced into the body What is Blood? -​ Blood circulates through the body delivering nutrients and removing waste materials -​ Blood is made up of red blood cells, white blood cells and platelets all suspended in plasma Plasma: -​ About 55% of your blood is made up of plasma. Plasma is a liquid made up of proteins, minerals, dissolved salts and water 7 Red Blood Cells: -​ Your body produces two million red blood cells every second. Red blood cells are responsible for carrying oxygen from your lungs to your cells and for carrying carbon dioxide from your cells to your lungs where it is exhaled -​ One drop of blood contains approximately five million red blood cells that each contain about 250 million molecules of hemoglobin -​ Hemoglobin is a protein that binds oxygen in the lungs and releases it throughout the body -​ Hemoglobin also binds carbon dioxide, removing it from cells and bringing it to the lungs -​ Red blood cells are also known as “erythrocytes” (erythro = red, kytos = hollow) and get their red colour from the Iran portion of hemoglobin where oxygen binds White Blood Cells: -​ White blood cells, also called “leukocytes”, defend the body against attack from foreign organisms, such as bacteria and some viruses and form antibodies that protect the body from future attacks -​ White blood cells make up approximately 1% of blood volume, but may increase to than double normal levels when your body is fighting infection -​ Phagocytes attack pathogens, engulf them and destroy them via phagocytosis -​ There are 5 types of white blood cells Neutrophils Most abundant leukocyte, found in body tissues and in the blood Eosinophils Found in the mucous lining of the digestive and respiratory tracts Basophils Aid in immunity by secreting substances that attract phagocytes to destroy pathogens Lymphocytes Produce antibodies that incapacitate pathogens and allow them to be easily detected and destroyed Monocytes Circulate in the bloodstream for only a few days before specializing as macrophages, which destroy bacteria 8 Platelets -​ Platelets contain the enzymes needed to turn clotting agents into fibrin - fibrous strands that heal wounds. Platelets collect around the edges of a wound, break themselves open, and release enzymes that promote chemical reaction needed to heal the wound -​ Platelets are also known as thrombocytes -​ Each cubic millimetre of blood contains 250,000 - 500,000 platelets Blood Vessels: -​ Three types of blood vessels make up the body’s network: Arteries, veins and capillaries Arteries: -​ Arteries are blood vessels that carry blood away from the heart. They have muscular walls that send the blood on its journey to the outer regions of the body -​ Each time the heart contracts, it sends out a gush of blood under high pressure. As high pressure blood enters the main artery, the artery wall expands and balloons out. Between each heartbeat or contraction, the pressure decreases and the arteries return to their normal shape. Each time the artery expands and contracts, it pushes the blood along. -​ The rhythm of arterial expansion and contraction is called the pulse. Your pulse rate is the same as your heartbeat rate because it is a single beat of the heart that causes each expansion and contraction of the artery. -​ Arteries are much thicker than veins and most are located deep within our bodies -​ A good reason for this is arterial blood is under high pressure, and if a large artery is cut blood literally spurts out of the victim and they can bleed out and die relatively quickly Veins: 9 -​ Veins are blood vessels that carry blood toward the heart. Veins don't have muscles of their own, but they do have valves. -​ Valves are folds or flaps of skin that prevent blood from backing up in the vein. Since the blood in your veins is at a much lower pressure, veins are located closer to our body's surface. -​ Blood doesn't spurt from a cut vein, so clotting can easily stop the flow. -​ The way blood moves through the veins is similar to the way air is forced out of the lungs. In both instances, an external set of muscles squeezes the organ, reduces its volume and increases its pressure -​ The pressure difference causes the flow of blood (or air) from a region of high pressure to one of low pressure. One difference is that veins have valves to prevent the backflow of blood. -​ Lungs don't need valves because there is nowhere for the air to flow back to Capillaries: -​ Capillaries are tiny blood vessels that join arteries to veins. Their walls are usually no more than one cell thick -​ Nutrients and gases diffuse into the cells through capillary walls. Wastes diffuse from the cells to the capillaries The Heart: -​ The heart - the driving force behind the flow of blood in your circulatory system - is a four-chambered heart that contracts about 70 times a minute. That's over 2,557,204,000 in a 70 year lifespan! -​ The heart adjusts its contraction rate (heartbeat) to match the body’s needs. When you’re resting, your heart pumps from 2.5 to 4 litres of blood every minute. If you begin to exercise, your heartbeat speeds up within seconds Anatomy of the Heart: 10 -​ The heart is made up of special kinds of muscle cells. The muscle cells in the heart are connected so they contract and expand at exactly the same moment -​ The human heart has 4 chambers of compartments: The left and right atria (atrium) and the left and right ventricle -​ The atria are smaller than the ventricles and their walls are thinner because they don't have to work as hard - they only pump blood to the next compartment -​ The ventricles, on the other hand, have to pump blood to the lungs and around the whole body. The left ventricle is the strongest of the heart's chambers -​ Each atrium is separated from its ventricle by a valve. The valves act like one-way doors Valves of the Heart: -​ The atria and valves are separated from each other by two valves called atrioventricular valves -​ The atrioventricular valve on the right side is called the tricuspid valve because it has three flaps -​ The atrioventricular valve on the left side is called the bicuspid valve because it has only two flaps 11 -​ The other two valves are called semilunar valves because of their half-moon shape Lymphatic System: -​ The lymphatic system is a network of vessels, nodes and organs -​ It collects the fluid that leaves the capillaries and detects any micro-organisms. It releases lymphocytes to kill any disease-causing bacteria -​ It maintains fluid balance by collecting excess fluid and depositing it back into the bloodstream -​ The fluid collected by lymphatic vessels is called lymph -​ Lymph is a very clear, watery fluid made up of protein molecules, salt, glucose, and other substances -​ As blood circulates through the body, blood plasma leaks into tissues Control of the Heartbeat: -​ Cardiac muscle is myogenic, which means it naturally contracts and relaxes, therefore it needs no impulse from a nerve to make it contract -​ The cardiac cycle is initiated by a small patch of muscle called the sinoatrial node (SAN) or pacemaker -​ This node sets the rhythm for all the other cardiac muscles -​ There is a delay between atrial contraction and ventricular contraction. -​ Fibres between the two chambers that do not conduct the excitation phase cause this delay. 12 -​ Therefore, the wave is conducted through a patch of fibres in the septum known as the atrio-ventricular node or AVN. -​ The wave is then transmitted (very rapidly) down to the bottom of the septum, where it spreads through the ventricles’ walls in an upward direction. -​ This movement causes the muscle to contract and the ventricles squeeze the blood out of the heart. -​ Fibrillation is the result of the contractions of the atria and ventricles becoming erratic and out of sync. -​ Using electric shock treatment to restart the SA node can rectify the problem. Lesson #4 The Respiratory System: -​ Respiration refers to the process that supplies oxygen to the body’s cells and rids the body of carbon dioxide -​ In mammals, respiration can be subdivided into: Breathing Act of taking air into and out of the lungs External Respiration Exchange of O2 and CO2 between the air and the blood Internal Respiration Exchange of O2 and surrounding tissue Cellular Respiration Using O2 to make energy with CO2 as the waste Tracing Air Through the Respiratory Tract: -​ Air enters the nostrils which: - warms and moistens the air - Mucus catches dust 13 -​ Air passes through the pharynx that connects the mouth and nasal cavity -​ Air passes by the glottis, the opening of the trachea -​ The epiglottis prevents food from entering the trachea -​ Then, air passes through the larynx, or “voice box” housing the vocal cords -​ When air passes through the cords when you exhale, they produce a sound. Loose chords produce a low sound while tight chords produce a higher sound -​ After passing through the larynx, air goes down the trachea -​ Semicircle cartilage rings line the trachea to prevent it from collapsing -​ Cilia line the upper respiratory tract that traps foreign particles (dust, bacteria) and propel them back into the nose and throat 14 Lower Respiratory Tract: -​ The trachea branches into 2 smaller passageways called bronchi -​ Each bronchus subdivides into finer and finer tubes called bronchioles -​ Each bronchiole ends in a grape like cluster called alveoli, in which the walls are one cell thick and is adjacent to a network of tiny capillaries, these capillaries are the site of gas exchange Mechanism of Breathing: Inhalation - The intercostal muscles contract, lifting the rib cage up and out. At the same time, the diaphragm contracts and pulls downwards. As the lungs expand, air moves in - The thoracic cavity is relatively air tight. Increasing the volume produces a decrease in air 15 pressure. Air then enters the lungs, moving from high to low pressure Exhalation - The intercostal muscles relax, allowing the rib cage to return to normal position. The diaphragm also moves upwards, resuming its domed shape. As the lungs contract, air moves out BELL JAR LUNG DEMO: - As the diaphragm is pulled down, the column of the cavity increases. This causes the pressure to fall. Air rushes in to equalize the pressure causing the balloons to inflate. - As the diaphragm is pushed up, the volume of the cavity decreases, the pressure rises, and the air rushes out of the balloons causing them to deflate Composition of Air -​ Inhaled oxygen to enter the bloodstream must first be dissolved in fluid lining the alveoli -​ Under normal conditions, the concentration in the oxygen in air is greater than the concentration in the blood - causing the oxygen to move in the bloodstream (Diffusion) Lung Capacity -​ Lung capacity is the volume of air in the lungs upon the maximum effort of inspiration Tidal Volume Volume of air inhaled and exhaled in a normal breath Inspiratory Reserve Volume Additional volume of air that can be taken in, beyond a regular or tidal inhalation Expiratory Reserve Volume Additional volume that can be forced out of the lungs, beyond a regular or tidal exhalation Vital Capacity Total volume of gas that can be moved in or out of the lungs Residual Volume Amount of gas that remains in the lungs and passageways even after a full exhalation