Biology 8 3rd Grading Reviewer PDF

BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. WEEK 1: DIGESTIVE SYSTEM 3. Stomach An organ system that is responsible to the digestion of fo...

BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. WEEK 1: DIGESTIVE SYSTEM 3. Stomach An organ system that is responsible to the digestion of foods. The digestive system is a complex network of organs and structures Function: The stomach further breaks down food using that work together to break down food into nutrients, absorb these gastric juices, which are highly acidic. nutrients into the bloodstream, and eliminate waste products o Chyme: The semi-liquid mixture of food and Digestion – breaking down food into smaller pieces and turning it digestive juices formed in the stomach. into nutrients. CHEMICAL AND MECHANICAL 4. Small Intestine Mechanical Digestion The small intestine is the primary site for nutrient absorption. It Mechanical digestion refers to the physical processes that break has three parts: food into smaller pieces. This prepares food for chemical digestion by increasing its surface area. Chemical Digestion 5. Large Intestine (Colon) change food into smaller molecules Chemical digestion involves breaking down complex molecules in Function: Absorbs water, electrolytes, and some food into simpler molecules through enzymatic and chemical vitamins. It also compacts undigested material into reactions. This allows nutrients to be absorbed by the body. feces. DIGESTIVE SYSTEM MAJOR ORGANS 1. Mouth - Digestion begins in the mouth. The teeth mechanically break food into smaller pieces (chewing), and the salivary glands 6. Rectum and Anus produce saliva to moisten food. Anus: The final part of the digestive system through Enzymes: Saliva contains amylase, an enzyme that which waste is excreted from the body. starts breaking down carbohydrates into simpler sugars. ACESSORY ORGANS 2. Liver Bile is a greenish-yellow fluid that emulsifies fats, breaking them into smaller droplets for easier digestion by enzymes. Filters and detoxifies harmful substances from the blood, such as drugs and alcohol. 3. Emulsification-a process of breaking up of large fat particles into smaller ones 3. Gallbladder Location: A small, pear-shaped organ located beneath the liver. o Stores and concentrates bile produced by the liver. 2. Pharynx and Esophagus 3. Pancreas Pharynx: The throat, which serves as a pathway for food and air. Location: Behind the stomach, in the upper abdomen. A soft triangular gland. Esophagus: A muscular tube that connects the throat to the stomach. Food is pushed down through peristalsis ▪ Regulates blood sugar by producing (wave-like muscle contractions). insulin. p BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. ▪ Produces digestive enzymes to digest Cause: Binge eating followed by purging. fats, carbohydrates and proteins DIGESTIVE PROCESSES 1. Ingestion -The process of taking food and liquids into the body WEEK 2: NUTRIENTS: through the mouth. Nutrition and Bioenergetics 2. Absorption - The process by which nutrients from digested food are transferred from the digestive tract into the bloodstream or Plants - Synthesize glucose during photosynthesis. lymph for distribution throughout the body. Plants utilize sunlight, carbon dioxide, and water to produce 3. Assimilation -The process by which absorbed nutrients are glucose, which serves as their energy source and contributes to taken up by body cells and used for energy, growth, repair, and the global oxygen supply. other functions. Humans/Animals - Derive energy from food (stored as 4. Egestion -The process of eliminating undigested food, waste potential chemical energy). products, and unabsorbed substances from the body as feces. The food we consume is broken down into smaller molecules, DISEASES allowing the body to extract energy stored in chemical bonds for 1. Diarrhea - Frequent, loose, or watery stools. cellular functions. 2. Constipation -Difficulty in passing stools or infrequent bowel movements (less than 3 per week). Law of Conservation of Energy - Energy cannot be created or 3. Hepatitis A -A viral infection that causes inflammation of the destroyed but can change forms. liver, usually transmitted through contaminated food or water. This fundamental law governs all energy processes, such as the 4. Hepatitis B -infection of the liver, transmitted through blood, transformation of light energy into chemical energy during sexual contact, or from mother to child. photosynthesis or the conversion of food energy into mechanical 5. Gallstones -Hardened deposits of bile that form in the energy in the body. gallbladder. 6. Peptic Ulcer -Open sores on the lining of the stomach or Metabolism - All chemical reactions in the body. duodenum. Metabolism includes both anabolic (building molecules) and 7. Hemorrhoids - Also known as piles, occur when rectal veins are catabolic (breaking down molecules) processes that maintain life. inflamed and enlarged after straining and eliminating hard stools. Basal Metabolism - Energy required for vital activities at rest. 8. Appendicitis - Inflammation of the appendix, a small pouch attached to the large intestine. Even when at rest, the body requires energy for essential functions like breathing, heartbeat, and maintaining body temperature. DISORDERS ASSOCIATED WITH IMPROPER OR SUFFICIENT DIET Calorie - Energy needed to raise the temperature of 1g of water Undernutrition - Undernutrition occurs when the body does not by 1°C. receive enough nutrients or energy to sustain normal growth, development, and physiological functions. It is often associated Calories measure the energy content of food and are used by the with poverty, food insecurity, or specific health conditions. body to perform activities and maintain metabolic processes. Overnutrition - Overnutrition occurs when the body consumes NUTRIENTS IN FOOD more nutrients or calories than it needs, leading to excessive 1. Carbohydrates - Main source of energy (from plants as energy storage and associated health risks. sugar/starch). EATING DISORDERS Carbohydrates are the body’s primary energy source. They also a. Anorexia Nervosa help form nucleic acids, synthesize mucus, and can be converted into amino acids or fats if needed. Cause: Psychological condition leading to restricted food intake. 2. Proteins - Growth and repair of cells, enzyme/hormone/antibody synthesis, energy source. b. Bulimia Nervosa p BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. Proteins play a critical role in tissue repair and the production of Night Blindness - Caused by Vitamin A deficiency, enzymes, hormones, and antibodies necessary for immune leading to poor vision in low light. defense and biochemical processes. Rickets - Resulting from Vitamin D deficiency, causing Amino Acids weak and deformed bones in children. o Essential Amino Acids - Must be obtained VITAMINS from food, such as Histidine and Lysine. Vitamin A - Maintains good vision, epithelial tissue cohesion, and promotes skin cell growth. o Non-Essential Amino Acids - Synthesized by the body. Sources: Fruits, yellow and green vegetables, carrots, liver, butter, egg yolk, and milk. o Deficiency - Leads to conditions like Deficiency can impair vision, particularly in low-light conditions, Kwashiorkor, a severe protein deficiency and hinder immune and skin health. disorder in children. Vitamin D - Promotes calcium and phosphorus 3. Fats - Long-term energy storage. absorption; aids in bone and teeth formation. Fats store energy more efficiently than carbohydrates and insulate Sources: Fortified milk, fish oils, margarine, egg yolk, and beef the body. However, excessive fat consumption may lead to fats. Arteriosclerosis, where fat deposits accumulate in blood vessels, Deficiency may lead to rickets or bone weakening due to poor restricting blood flow. calcium utilization. 4. Vitamins - Essential organic compounds required in small amounts. Vitamin E - Maintains proper RBC structure, supports muscle maintenance, and acts as a coenzyme in the Fat-Soluble Vitamins (A, D, E, K) - Stored in fats and Krebs cycle. utilized as needed. Sources: Meat, dairy, whole grains, liver, and green leafy Water-Soluble Vitamins (B, C) - Not stored; must be vegetables. supplied regularly through diet. This vitamin protects cells from oxidative stress and supports overall muscle health. 5. Minerals - Build strong bones and teeth. Vitamin K - Essential for synthesizing prothrombin for Essential for bone strength, neural function, and enzyme activity. blood clotting. Examples include calcium and phosphorus. Sources: Green leafy vegetables and liver. 6. Water - Vital for survival (70% of body weight). Deficiency can lead to hemorrhage, a condition where the blood fails to clot, causing excessive bleeding. Water is crucial for regulating temperature, transporting nutrients, and eliminating waste. The recommended intake is 3 liters/day to WEEK 3: CARDIOVASCULAR SYSTEM maintain hydration and bodily functions. The cardiovascular system - It is the transport system of the body, comprising the blood, heart, and blood 7. Fiber - Found in vegetables and fruits. vessels. Fiber aids digestion by promoting healthy bowel movements and FUNCTIONS OF THE CARDIOVASCULAR SYSTEM supporting gut health. Transport of substances COMMON DISORDERS 1. Transport of nutrients - The cardiovascular Kwashiorkor - Protein deficiency in children. system transports nutrients absorbed from the This disorder causes swelling, growth failure, and muscle wasting digestive system to storage sites (such as the due to insufficient protein intake. liver) or directly to cells for energy. Arteriosclerosis - Fat deposits in blood vessels. 2. Oxygen and carbon dioxide exchange - Oxygen and carbon dioxide are exchanged Excessive fat accumulation narrows blood vessels, increasing the between the blood and tissues at the risk of heart disease and stroke. capillaries, supporting cellular respiration. Vitamin Deficiency - Lack of specific vitamins leading to various disorders. p BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. 3. Transport of waste products - Other waste right ventricle sends deoxygenated blood to the lungs via products, such as urea, are transported to the the pulmonary arteries, while the left ventricle pumps kidneys for excretion. oxygenated blood to the body through the aorta. Heart’s valves - They ensure one-way flow of blood. 4. Transport of hormones - Hormones produced Heart valves prevent backflow, ensuring blood flows in by endocrine glands are carried through the the correct direction. Their proper functioning is crucial bloodstream to target organs and tissues, for maintaining effective circulation throughout the body. regulating various physiological processes. Types of Heart Valves - These are categorized based on their location and function in regulating blood flow. Immunity Semilunar valves - The pulmonary valve and aortic valve o White blood cells and antibodies - These are are located between the ventricles and their transported through the bloodstream, corresponding arteries. contributing to the body's immune response The pulmonary valve regulates the flow of deoxygenated against infections and foreign substances. blood from the right ventricle into the pulmonary artery, which leads to the lungs. The aortic valve controls the flow of oxygenated blood from the left ventricle into the aorta, ensuring it reaches the rest of the body. COMPONENTS OF THE CARDIOVASCULAR SYSTEM Heart Atrioventricular (AV) valves - The tricuspid valve and mitral (bicuspid) valve are located between the atria and The heart - A four-chambered, hollow muscular organ the corresponding ventricles. approximately the size of your fist. The tricuspid valve separates the right atrium from the right ventricle, while the mitral valve (also known as the Type of muscle in the heart - Cardiac muscle, which is bicuspid valve) separates the left atrium from the left specialized for continuous contraction. ventricle. These valves open and close in response to pressure changes, ensuring blood moves from the atria Location of the heart to the ventricles without backflow. o Superior surface of the diaphragm. Semilunar valve structure - The pulmonary and aortic valves are called semilunar valves because their leaflets o Left of the midline. are shaped like half-moons. This unique shape allows the valves to function o Anterior to the vertebral column, posterior to efficiently, preventing blood from flowing back into the the sternum. ventricles after it is pumped out. Posterior vena cava - Responsible for returning FUNCTIONS OF THE HEART deoxygenated blood from the lower part of the body to Generating blood pressure - The heart generates the the heart. pressure required to circulate blood throughout the The posterior vena cava, also known as the inferior vena body. cava, carries blood from the abdomen, pelvis, and lower Routing blood - The heart routes blood into the limbs to the right atrium of the heart. pulmonary and systemic circulations. Anterior vena cava - Responsible for returning deoxygenated blood from the upper part of the body to Separation of pulmonary and systemic circulations - the heart. The heart ensures that oxygenated and deoxygenated Also referred to as the superior vena cava, it collects blood do not mix. blood from the head, neck, upper limbs, and chest, delivering it to the right atrium. PARTS OF THE HEART Aorta - Serves as the main artery that carries oxygenated Atria - The atria act as receiving chambers for blood blood from the heart to the rest of the body. returning to the heart.The atria are thin-walled chambers The aorta is the largest artery in the body. It branches into located at the top of the heart. They collect blood from smaller arteries, supplying oxygen and nutrients to veins and pass it to the ventricles. The right atrium tissues and organs. The high-pressure flow in the aorta receives deoxygenated blood from the body, while the ensures efficient distribution of blood. left atrium receives oxygenated blood from the lungs. Pulmonary arteries - Bring deoxygenated blood from the Ventricles - The ventricles act as pumping chambers to heart to the lungs. move blood out of the heart. These arteries originate from the right ventricle and The ventricles have thicker walls compared to the atria, transport blood to the lungs, where carbon dioxide is as they generate the force needed to pump blood. The p exchanged for oxygen during respiration. BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. Pulmonary veins - Bring oxygenated blood from the have a higher proportion of smooth muscle in the tunica lungs back to the heart. media. This allows them to regulate blood flow by The pulmonary veins return oxygen-rich blood to the left constricting or dilating their lumen in response to atrium, completing the pulmonary circulation cycle. This signals, ensuring blood is directed to where it is most blood is then pumped into the left ventricle and needed. distributed to the rest of the body. 3. Arterioles - The smallest arteries, with a caliber of between 0.3 mm and 10 microns (µm). Arterioles are critical in regulating blood flow into capillary beds. Their small size and muscular walls enable them to control resistance in the circulatory system, playing a significant role in blood pressure regulation. VEINS Transport blood from tissues back to the heart. Veins return deoxygenated blood (except for pulmonary veins) to the heart at low pressure. They act as capacitance vessels, storing a significant volume of blood while maintaining flow. Characteristics - Thinner walls than arteries, containing valves to prevent backflow. The walls of veins are less muscular, and elastic compared to arteries, allowing them to accommodate large volumes of blood. Valves within veins, especially in the limbs, prevent the backflow of blood and assist its return to the heart against gravity. BLOOD VESSELS Blood Vessels – A closed network of tubes where blood Superior and Inferior Vena Cava - Large veins that travels. These include: return blood to the right atrium. The superior vena cava collects deoxygenated blood o Arteries from the upper body (head, neck, and arms), while the o Veins inferior vena cava collects it from the lower body (abdomen and legs). Both deliver blood to the right o Capillaries atrium for oxygenation in the lungs. Pulmonary Veins - Carry oxygenated blood from the ARTERY lungs to the left atrium. Pulmonary veins are unique among veins as they Arteries transport blood under high pressure generated by the transport oxygen-rich blood. They play a critical role in heart. This ensures oxygen and nutrients are efficiently delivered completing pulmonary circulation by returning to the body's tissues. oxygenated blood to the heart for systemic distribution. The arterial walls consist of three layers: the tunica intima, tunica Venules - The smallest veins, receiving blood from media, and tunica adventitia. The thick tunica media (composed capillaries. of smooth muscle and elastic fibers) enables arteries to handle Venules are formed by the convergence of capillaries. the pressure of blood ejected from the heart. They drain deoxygenated blood from tissues and gradually converge into larger veins, continuing the 1. Elastic Arteries - Large vessels near the heart that return of blood to the heart. stretch and recoil to maintain blood pressure. Elastic arteries, such as the aorta and its major CAPILLARIES (5 8 micron) branches, have an abundance of elastic tissue in the The smallest blood vessels, bringing blood to the tunica media. This elasticity allows them to expand smallest and farthest cells. during systole (ventricular contraction) and recoil during diastole (ventricular relaxation), smoothing the flow of This is where the exchange of nutrients and gases with blood and maintaining pressure. the cells occurs. 2. Muscular Arteries - Distribute blood to specific organs, with more smooth muscle for precise control. Muscular arteries, such as the renal or coronary arteries, p BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. Megakaryocytes. These are important in the process of blood clotting. BLOOD FLOW The pulmonary circuit and systemic circuit - Two interconnected pathways that work together to facilitate the flow of blood throughout the body. The pulmonary circuit (pulmonary circulation) - Responsible for transporting deoxygenated blood from the heart to the lungs and then returning oxygenated blood back to the heart. BLOOD Blood is a specialized connective tissue made up of plasma and The systemic circuit (systemic circulation) - cells, each with important functions to maintain health. Responsible for distributing oxygenated blood from the heart to all the tissues and organs of the body, providing 1. Plasma: The liquid part of blood, making up about 55%. them with the oxygen and nutrients needed for cellular It's mostly water (90%), carrying nutrients, hormones, functions. waste, and gases. It also contains proteins like albumin (which helps maintain pressure), fibrinogen (for clotting), BLOOD FLOW PROCESS and globulins (for immunity). Deoxygenated Blood Returns to the Heart - Blood returns from the body to the heart through the superior 2. Red Blood Cells (RBCs): cells that transport oxygen and inferior vena cava. from the lungs to the different parts of the body. It does Right Atrium - Blood enters the right atrium of the heart. not possess nucleus. Right Atrium to Right Ventricle - Blood flows from the right atrium through the tricuspid valve into the right 3. White Blood Cells (WBCs): protect the body against ventricle. invading pathogen. It possesses nucleus. Larger that RBC but fewer in number.For every WBC in the blood, To the Lungs for Oxygenation - The right ventricle sends there are about 700 RBCs. blood through the pulmonary valve to the pulmonary artery, which takes it to the lungs to pick up oxygen. Oxygenated Blood Returns to the Heart - Oxygen-rich Neutrophils - Engulf and digest bacteria, acting as blood returns from the lungs to the left atrium through the body's initial defense team. They are the most the pulmonary veins. abundant white blood cells and are the first to respond to infections. Left Atrium to Left Ventricle - Blood flows from the left Eosinophils - Release chemicals to destroy atrium through the bicuspid (mitral) valve into the left parasites and help control allergic responses. They ventricle. are particularly important in defending against To the Body for Distribution - The left ventricle pumps parasitic infections and play a key role in allergic oxygenated blood through the aortic valve into the reactions like asthma. aorta, which sends it to the rest of the body. Basophils - Involved in inflammatory responses and allergy-related reactions. They release LHYMPHATIC SYSTEM histamine during allergic responses, contributing to The lymphatic system is a network of o rgans, vessels, inflammation and symptoms like itching and and tissues that moves a colorless, watery fluid called swelling. lymph back into your bloodstream. Lymphocytes - Play a major role in the immune response by producing antibodies (B cells) and It is a vital part of your immune system, protecting you recognizing and killing infected cells (T cells). They from infection and removing old or abnormal cells from are key players in both the adaptive and innate your body. immune systems. Monocytes - Engulf and digest dead cells, bacteria, The lymphatic system also helps maintain fluid levels and other debris left behind after an infection. They and absorbs fats and fat-soluble vitamins. later transform into macrophages when they enter tissues, continuing their cleanup job and helping in FUNCTIONS OF THE LYHMPHATIC SYSTEM immune responses. 1. Arteriole - Carries oxygen-rich blood to the capillaries in tissues. 4. Platelets: Are not true cells but fragments of the cytoplasm from large bone marrow cells known as p BIOLOGY GRADE EIGHT YLO: THIRD GRADING REVIEWER NOTE: MAXIMIZE THE USE OF OTHER RESOURCES SUCH AS GENYO AND YOUR BOOKS. 2. Tissue Fluid - Blood pressure forces water, oxygen, and Lymphocytes - These are specialized white blood cells nutrients out of the capillaries into the tissue spaces, that play a key role in the immune system. There are creating tissue fluid. different types of lymphocytes, including B-cells, which 3. Tissue Cells - The tissue fluid surrounds the tissue produce antibodies, and T-cells, which directly attack cells, delivering oxygen and nutrients, and picking up infected cells. They circulate through the lymphatic waste. system and bloodstream to detect and respond to 4. Tissue Spaces - The area around the cells where tissue foreign invaders. fluid collects. 5. Lymphatic Capillary - Extra tissue fluid that isn’t DISORDERS OF THE BLOOD VESSELES returned to blood capillaries is absorbed by the Atherosclerosis - Build-up of plaque (cholesterol, fat, lymphatic capillaries, turning into lymph. and other substances found in blood) inside the walls of 6. Lymphatic Vessel - The lymph is carried through the arteries that causes them to degenerate, harden, and lymphatic vessels and eventually filtered in lymph lose elasticity. nodes. Stroke - Results from blockage brought about by the 7. Venule - The leftover fluid that wasn’t picked up by hardening of arteries in the brain or neck vessels leading lymphatic capillaries is returned to the bloodstream to the brain. Stroke can also occur from a hemorrhage through venules. where a diseased artery suddenly bursts. Angina Pectoris - Reduced blood flow causes a painful sensation in the chest, left arm, and shoulder. Myocardial Infarction (Heart Attack) - Occurs when a large part of the heart muscle is damaged due to blocked blood flow to the Hypertension (High Blood Pressure) - Results from the tightening of the arterioles, which increases resistance to blood flow. Endocarditis - Inflammation of the innermost layer of the heart caused by rheumatic fever, typically resulting from untreated bacterial infections caused by Streptococcus pyogenes. DISORDERS OF THE BLOOD ORGANS OF THE LYMPHATIC SYSTEM Hemophilia - A genetic condition where the blood does Lymph Nodes - Small, bean-shaped structures that filter not clot properly, causing persistent bleeding. lymph (fluid collected from tissues) and trap harmful Anemia - A condition where the red blood cell (RBC) substances like bacteria, viruses, and cancer cells. They count stays persistently low (below 4 million), affecting also house immune cells like lymphocytes that help the ability of RBCs to carry oxygen. fight infections. Leukemia - A blood disorder characterized by the Lymphatic Vessels - A network of tubes that carry lymph abnormal increase in the number of white blood cells throughout the body, like how blood vessels carry blood. (WBCs), making it one of the most dangerous blood They transport lymph to the lymph nodes and back into disorders. the bloodstream. Thymus - Located behind the breastbone, the thymus produces T-cells, a type of lymphocyte (white blood cell) that is important for immune responses. Spleen - Filters blood, removing old or damaged red blood cells, and stores lymphocytes (including B-cells and T-cells) that help fight infections. It also helps remove waste from the blood. Tonsils - Lymphoid tissues located at the back of the throat. They help trap pathogens that enter through the mouth or nose and play a role in immune defense. Bone Marrow - The soft tissue inside bones that produces all blood cells, including lymphocytes (B-cells and T-cells). These immune cells are crucial for defending the body against pathogens. p