Organ Systems- Digestive, Circulatory and Respiratory PDF

Digestive System The digestive system is a series of organs that work together to break down food into nutrients that the body can absorb and use for energy, growth, and repair. Functions of the Digestive System 1. Ingestion: Taking in food. 2. Digestion: Breaking food into smaller molecules...

Digestive System The digestive system is a series of organs that work together to break down food into nutrients that the body can absorb and use for energy, growth, and repair. Functions of the Digestive System 1. Ingestion: Taking in food. 2. Digestion: Breaking food into smaller molecules: o Mechanical digestion: Physical breakdown of food (e.g., chewing, churning). o Chemical digestion: Enzymes and chemicals break down food molecules. 3. Absorption: Transport of nutrients into the bloodstream or lymph. 4. Egestion: Removal of undigested food and waste products. Organs of the Digestive System and Their Functions Organ Function Mouth Chews food (mechanical digestion). Saliva contains amylase, which begins starch digestion. Esophagus Moves food to the stomach using muscle contractions called peristalsis. Stomach Releases gastric juice (contains HCl and pepsin) to digest proteins. Churns food into chyme. Small Intestine Completes digestion with enzymes and absorbs nutrients into the blood or lymph. Pancreas Produces enzymes (amylase, lipase, protease) for digestion. Liver Produces bile, which emulsifies fats. Processes absorbed nutrients. Gallbladder Stores and releases bile into the small intestine. Large Intestine Absorbs water and forms feces. Rectum & Anus Stores and eliminates waste. What happens in the digestive process? The digestive process involves lots of steps and several stops as food and liquid move through your digestive system: 1. Digestion starts even before you take that first bite of food. When you see and smell food, your salivary glands get to work. They release saliva so you have some spit in your mouth to moisten food when you start chewing. 2. Next, your chewed-up food moves from your mouth to your esophagus. Your esophagus uses a process known as peristalsis to send food to your stomach. 3. Your stomach releases acid and enzymes that break food down. 4. Next, your small intestine turns semisolid food into fluid to absorb nutrients. 5. Your pancreas and liver help by sending digestive juices to your small intestine. Your gallbladder contributes bile. 6. The final step is when your small intestine sends leftover food waste to your large intestine. That food waste becomes feces that leaves your body via your rectum and your anus. How can I keep my digestive system healthy? In general, the following are ways to keep your digestive system healthy: 1. Drink enough water: Water helps the food you eat flow more easily through your digestive system. How much water you need depends on factors like your activity level, metabolism and size. 2. Get your fill of fiber: Fiber helps digestion. Adding fiber to balanced meals of lean protein, fruits and vegetables can keep your digestive system working as it should. 3. Add probiotics: Probiotics are good bacteria that fight off the bad bacteria in your digestive system. 4. Eat mindfully: Mindful eating focuses on how and why you’re eating. Practicing mindful eating helps you to slow down and chew your food thoroughly. 5. Avoid alcohol and smoking: Alcohol can increase the amount of acid in your stomach and can cause heartburn, acid reflux and stomach ulcers. Smoking almost doubles your risk of having acid reflux. 6. Manage your stress: Stress is associated with digestive issues such as constipation, diarrhea and IBS (irritable bowel syndrome). Respiratory System The respiratory system is responsible for the intake of oxygen and the removal of carbon dioxide, supporting the body’s energy needs through the process of respiration. It ensures a continuous supply of oxygen to the cells and helps maintain proper gas concentrations in the blood. Functions of the Respiratory System 1. Breathing (Ventilation): o Inhalation: Drawing oxygen-rich air into the lungs. o Exhalation: Expelling carbon dioxide-rich air from the lungs. 2. Gas Exchange: Swapping oxygen and carbon dioxide between the lungs and the blood. 3. Respiration: Oxygen is used by cells to produce energy from glucose. Key Structures and Their Roles 1. Nasal Cavity and Mouth Function: Air is inhaled, warmed, moistened, and filtered. The nasal cavity contains tiny hairs (cilia) and mucus to trap dust and pathogens. 2. Pharynx and Larynx Pharynx: A passageway for air and food. Larynx (Voice Box): Produces sound and directs air into the trachea. 3. Trachea (Windpipe) A tube reinforced with cartilage rings to prevent collapse. Lined with cilia and mucus to trap and move particles out of the airway. 4. Bronchi and Bronchioles Bronchi: Two branches of the trachea, each leading to a lung. Bronchioles: Smaller airways branching from the bronchi, carrying air to the alveoli. 5. Lungs The main organ of the respiratory system, containing millions of tiny air sacs called alveoli. 6. Alveoli Structure: Thin-walled, balloon-like structures surrounded by capillaries. Function: Site of gas exchange through diffusion. 7. Diaphragm and Intercostal Muscles Diaphragm: A dome-shaped muscle that contracts to pull air into the lungs. Intercostal Muscles: Located between the ribs, they help expand and contract the chest cavity. Process of Breathing (Ventilation) Inhalation (Breathing In) 1. The diaphragm contracts and flattens. 2. Intercostal muscles contract, pulling the ribcage up and out. 3. The chest cavity volume increases, lowering air pressure inside. 4. Air is drawn into the lungs to equalize pressure. Exhalation (Breathing Out) 1. The diaphragm relaxes and curves upward. 2. Intercostal muscles relax, allowing the ribcage to move down and in. 3. The chest cavity volume decreases, increasing air pressure inside. 4. Air is pushed out of the lungs. Gas Exchange at the Alveoli Oxygen diffuses from the alveoli into the blood in the capillaries. Carbon dioxide diffuses from the blood into the alveoli to be exhaled. This process occurs because of the concentration gradient: o High oxygen concentration in the alveoli → low oxygen concentration in blood. o High carbon dioxide concentration in blood → low carbon dioxide concentration in alveoli. How can I keep my respiratory system healthy? To keep your respiratory system healthy: 1. Don’t smoke or vape. Smoking causes many lung and airway diseases or makes them worse. Vaping liquids often have many of the same ingredients as cigarettes. 2. Avoid pollutants that can damage your airways. This includes secondhand smoke, chemicals and radon (a radioactive gas that can cause cancer). Wear a mask if you’re exposed to fumes, dust or other types of pollutants during your job or hobbies. 3. Stay hydrated. Drinking plenty of water keeps the mucus in your lungs thin and easier to clear out. 4. Exercise regularly. Exercise keeps the muscles in your lungs strong and makes breathing easier. 5. Prevent infections. Washing your hands often and getting vaccinated against respiratory illnesses can help prevent you from getting sick. Circulatory System The circulatory system is a network of organs and vessels that transports blood, nutrients, gases, and waste products throughout the body. It plays a key role in maintaining homeostasis and supporting cellular respiration. Key Components of the Circulatory System Component Description Heart A muscular pump that circulates blood through the body. Blood A fluid that carries oxygen, nutrients, hormones, and waste. Blood Vessels Tubes through which blood flows (arteries, veins, and capillaries). The Heart Structure: Atria: Two upper chambers that receive blood. Ventricles: Two lower chambers that pump blood out of the heart. Valves: Prevent backflow of blood (e.g., tricuspid, bicuspid, pulmonary, and aortic valves). Function: The heart works as a double pump: 1. Right side: Pumps deoxygenated blood to the lungs for gas exchange. 2. Left side: Pumps oxygenated blood to the rest of the body. Pathway of Blood Through the Heart: 1. Blood enters the right atrium from the body (via the vena cava). 2. Flows into the right ventricle, then is pumped to the lungs through the pulmonary artery. 3. Oxygenated blood returns to the left atrium via the pulmonary vein. 4. Enters the left ventricle, then is pumped to the body through the aorta. Blood Vessels Type of Vessel Structure Function Arteries Thick, muscular walls; high Carry oxygenated blood away from the heart pressure. (except the pulmonary artery). Veins Thinner walls; contain valves Carry deoxygenated blood toward the heart (except to prevent backflow. the pulmonary vein). Capillaries Very thin walls (one cell Site of nutrient, gas, and waste exchange between thick). blood and tissues. Blood Components Component Description Function Red Blood Contain hemoglobin; no Transport oxygen from the lungs to tissues and carbon Cells nucleus. dioxide from tissues to the lungs. White Blood Larger cells with a Defend the body against infections and pathogens. Cells nucleus. Platelets Cell fragments. Help in blood clotting to prevent excessive bleeding. Plasma Straw-colored liquid. Transports nutrients, hormones, waste products, and heat.