Section 3 Unit B Cells & Systems PDF

3.1 Digestive System Your digestive system is in charge of breaking down the food you eat into parts small enough to be used by your cells. Each of the different energy sources: carbohydrates, lipids, and proteins must be broken down into small usable particles as they travel through your digestive...

3.1 Digestive System Your digestive system is in charge of breaking down the food you eat into parts small enough to be used by your cells. Each of the different energy sources: carbohydrates, lipids, and proteins must be broken down into small usable particles as they travel through your digestive system. Types of Digestion 1. Mechanical Digestion involves the physical breakdown of food into very small pieces. 2. Chemical Digestion involves the breakdown of large particles into smaller particles by substances called enzymes. Path of your Digestive System 1 The food moves down toward your stomach by a wave-like movement known as peristalsis. Peristalsis is caused by contractions of muscle tissue that lines the esophagus. salivary glands makes saliva which chemically breaks down food using enzymes. tongue - mixes saliva with the food. teeth moved by the jaw to break down food. oesophagus wave-like muscle contractions called peristalsis, move the food down the oesophagus to the stomach. 2 The muscular wall of the stomach churns the food back and forth, while mixing it with secretions from the wall of the stomach, known as gastric juice. Gastric juice is composed of mucus, hydrochloric acid, water, and digestive enzymes. liver makes bile which helps neutralise stomach acid and digest some vitamins gall bladder bile is stored here until it is needed. stomach churns the food and is mixed with acid, gastric juices, until it turns into a goopy soup. stomach to small intestine wave-like muscle contractions called peristalsis, move the food down the oesophagus to the stomach. 3 stomach. duodenum - bile continues to break down food. large intestine absorbs water and electrolytes. pancreas makes enzymes that break down food. small intestine food is pushed through the small intestine by contractions absorbing nutrients. The area to absorb nutrients is increased by finger-like projections called villi. This process occurs over a distance, on average, of 22 feet. Breathing Breathing is the process your respiratory system uses to move air in and out of your lungs. Breathing occurs because of your rib and diaphragm muscles. Gas Exchange Process bronchus large windpipe carrying oxygen from the trachea to the lungs. bronchiole smaller branches that the bronchus divides into. capillaries the smallest blood vessels. alveoli the tiny air sacs at the end of the bronchioles which exchanges oxygen for carbon dioxide. 3.3 Circulatory System One of the circulatory system’s jobs is to deliver the nutrients absorbed by your digestive system to each cell in your body. Besides nutrients, your circulatory system must also transport oxygen to your cells and remove waste products. The circulatory system, then, is your body’s transportation network. The Heart Superior Vena Cava - brings deoxygenated blood back from the body. Aorta - carries blood from the left ventricle to the body. Left Pulmonary Artery Carries oxygen poor blood to your lungs veins from lungs to heart veins from lungs to heart Left atrium - receives oxygen rich blood from the lungs and pumps it into the left ventricle. Right atrium - receives blood low in oxygen from the body and pumps it into the right ventricle. Left ventricle - when it contracts it pumps blood to the body. Right ventricle - when it contracts it pumps blood to the lungs. Inferior Vena Cava- large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. major vein from lower body to heart Arteries, Veins & Capillaries Arteries - Vessels that carry blood away from the heart to all parts of your body. Veins - return blood from the body to the heart. Capillaries - located between arteries and veins which diffuse nutrients and gases. They can diffuse nutrients and gases easily because they are only one cell thick The Blood Red Blood Cells - carry oxygen, have no nucleus in order to carry as much oxygen as possible White Blood Cells - fight infection. Platelets - helps stop the bleeding at cuts Plasma (Hemoglobin) - the liquid portion of your blood transports nutrients to your cells and carries away waste product such as carbon dioxide. 3.4 Excretory System The body produces a number of different types of wastes. These wastes are poisonous, and, if not removed from the body, can cause you serious harm. The job of waste removal, excretion, is done by the excretory system. The interesting thing about the excretory system is that it involves organs from other systems. Liver - It takes the highly toxic ammonia produced by the body’s cells out of the bloodstream and converts it into a less harmful substance called urea. This less harmful urea is released back into the bloodstream. Kidney - The kidney is the waste filtering and disposal system of the body. ⅓ of all blood passes through the kidneys prior to flowing to the rest of the body tissues. The kidney has millions of nephrons. These microscopic units remove wastes from the blood and produce urine. Bladder - The bladder is connected to the kidneys by a long tube called a ureters. The purpose of the bladder is to act as a storage location for urine before it is expelled through the urethra. Urine & Disease Doctors can determine if you have certain diseases by testing your urine. Kidney Failure - often those with failing kidneys have protein in their urine because their kidneys have lost the ability to filter blood properly. High blood pressure and diabetes are the two most common causes of kidney failure. They can also become damaged from physical injury, diseases, or other disorders. Diabetes - those with diabetes will often have glucose in their urine. Their cells cannot absorb glucose, and glucose builds up in the bloodstream. Sometimes, as a result of damage or disease, kidneys don’t work properly. It’s called a kidney dialysis machine, and it removes all the wastes from the blood that a kidney normally would. Stimuli (the plural form of stimulus) can occur in many forms, such as changes in pressure, heat, cold, light, sound, or body chemistry. Stimuli may be external (outside your body), such as when you walk from the cold outdoors into a warm room, or they can be internal, such as the arrival of food in your stomach. It is the job of the nervous system to monitor and respond to these stimuli. Neurons The nervous system is mostly made up of one type of tissue called nervous tissue. Nervous tissue is made entirely of specialized cells called neurons. Your brain, spinal cord, and nerves are all made of them. A neuron’s job is to send and receive messages. soma - the core of the cell containing a nucleus dendrites - A dendrite (tree branch) is where a neuron receives input from other neurons connected by synapses. axon - The axon is a long extension of the cell that ends in small branches. It carries impulses away from the cell body & away from muscles and glands. CNS - Central Nervous System Command center of the body containing the brain and spinal cord. The spinal cord connects the brain to the peripheral nervous system, and it acts as a highway for messages between the brain and the body. It contains a type of neuron called an interneuron. These neurons connect one neuron to another. The three broad functions of the CNS are to: - take in sensory information - process information, and - send out motor signals CNS - Spinal Cord The spinal cord is an elongated cylinder of neuron cell bodies, bundles of axons and other cells, protected by connective tissue and bone. It connects to the brain at the medulla oblongata and runs down the vertebral column, the hollow tunnel enclosed within the vertebrae of the spine. The spinal cord is part of the central nervous system and serves as a kind of superhighway. Sensory information and motor commands travel up and down, heading to and from the brain. These signals speed in and out of the spinal cord via spinal nerves—the “on-ramps and off-ramps” that branch out to supply the limbs, torso, and pelvis. Some incoming signals demand a simple, immediate response. The spinal cord can shoot out a reflex command without bothering the brain. CNS - Brain The brain controls what you think and feel, how you learn and remember, and the way you move and talk. But it also controls things you're less aware of — like the beating of your heart and the digestion of your food. Think of the brain as a central computer that controls all the body's functions. The rest of the nervous system is like a network that relays messages back and forth from the brain to different parts of the body. PNS - Peripheral Nervous System This system comprises of all the nerves that branch out from the brain and spinal cord. Your peripheral nervous system has two main subsystems: autonomic and somatic. 1. Autonomic: These are nervous system processes your brain runs automatically and without you thinking about them. (reflex response 2. Somatic: These are functions you manage by thinking about them. Types of Nerves The nervous system is comprised of bundles of nerves. There are three types of nerves found within the peripheral system.. 1. 2. 3. Sensory: These nerves carry information to your brain and spinal cord. They either connect directly to your brain through your cranial nerves or carry information to your spinal nerves, which then feed into your spinal cord. The sensory nerve connections to your spinal cord are on the back of your spinal cord. Motor: These nerves carry command signals from your brain to various parts of your body. They only carry information away from your brain. The motor nerve connections are on the front of your spinal cord; meaning, these nerves are for sending muscle movement commands only. Autonomic: These nerves control the automatic functions of the organs and systems in your body. Your autonomic nerves often involve mixed nerve fibers, some of which carry commands from your brain to their destination, and others that carry information about an organ’s function back to your brain. The Reflex Response Reflex action is a sudden and involuntary response to stimuli. It helps organisms to quickly adapt to an adverse circumstance that could have the potential to cause bodily harm or even death. If you put your hand on a hot stove, a reflex causes you to immediately remove your hand before a "Hey, this is hot!" message even gets to your brain. Other examples: When light acts as a stimulus, the pupil of the eye changes in size. Sudden jerky withdrawal of hand or leg when pricked by a pin. Coughing or sneezing, because of irritants in the nasal passages. Knees jerk in response to a blow or someone stamping the leg.