TISSUES Are a group of cells that perform a single function. There are 4 basic types of tissues: Epithelial, Connective, Nervous, Muscle. Epithelial – includes glands and tissues that cover interior and exterior body surfaces. Connective – provides support for the body and connects its parts. Nervous – transmits nerve impulses throughout the body. Muscle – along with bones, enables the body to move.
NERVOUS SYSTEM Consists of the Brain, Spinal Cord, and Peripheral nerves. Recognizes and coordinates the body’s response to changes in its internal and external environments. Messages carried by the nervous system are electrical signals called impulses.Made of acell body,dendrites Nerve celland called aaxons neuron.
NERVOUS SYSTEM Cells that transmit impulses are called neurons. Neurons are classified into 3 types based on the direction in which the impulse travels. There are Sensory, Motor, and Interneurons. Sensory neurons – carry impulses from organs to the spinal cord and brain. Motor neurons – carry impulses from the brain and spinal cord to muscles and glands. Interneurons – connect sensory and motor neurons and carry impulses between them.
NERVOUS SYSTEM Divided into 2 major divisions: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS is the control center of the body. Relays messages, processes and analyzes information. Consists of the brain and spinal cord. The PNS receives information from the environment and relays commands from the CNS to organs and glands. Consists of all the nerves and associated cells that are not part of the brain and spinal cord.
CNS Brain – place to which impulses flow and where they originate. Contains about 100 billion neurons (many are interneurons). Has a mass of about 1.4 Kilograms (about 2.5 pounds). Parts of the brain are cerebrum, cerebellum, brain stem, thalamus, hypothalamus. Spinal Cord –the main communications link between the brain and the rest of the body. Certain kind of information, including kinds of reflexes are processed directly in the spinal cord. A reflex is a quick, automatic response to stimulus. Allows your body to respond to danger immediately, without thinking.
THE BRAIN (THE CEREBRUM) The largest and more prominent region of the brain. Responsible for the voluntary activities of the body. Site of intelligence, learning, and judgment. Divided into 2 hemispheres - connected by a bond called the corpus callosum. Divided into 4 lobes Each side of cerebrum deals with the opposite side of body. Right hemisphere associated with creativity and artistic ability. Left hemisphere associated with analytical and mathematical ability.
THE BRAIN (THE CEREBELLUM & BRAIN STEM) Cerebellum – second largest region of the brain located at the back of the skull. Coordinates and balances the actions of the muscles so the body can move gracefully and efficiently. Brain Stem – connects the brain and spinal cord located just below the cerebellum Includes 2 regions – the pons and medulla oblongata. Body’s most important functions – blood pressure, heart rate, breathing, and swallowing controlled by the brain stem.
THE BRAIN (THALAMUS & HYPOTHALAMUS) Found between the brain stem and cerebrum. Thalamus – receives messages from all sensory receptors and sends it to the proper part of the cerebrum. Hypothalamus – below the thalamus. Control center of hunger, thirst, fatigue, anger, and body temperature. Controls coordination of the nervous and endocrine systems.
PNS Can be divided into the sensory and motor divisions. Nerves are axons bundled together with blood vessels and connective tissue. Sensory – transmits impulses from sense organs to the CNS. Motor – transmits impulses from the CNS to muscles and glands. Divided into Somatic and Autonomic nervous systems. Somatic –regulates activities that are under conscious control. Movement of the skeletal muscles. Autonomic – regulates activities the are involuntary. Beating of the heart.
SENSES The body contains millions of neurons that react to stimuli from the environment, including light, sound, motion, chemicals, pressure, and changes in temperature. These neurons are known as Sensory Receptors. 5 categories of sensory receptors: pain receptors, thermoreceptors, mechanoreceptors, chemoreceptors, and photoreceptors.
SENSES Pain Receptors – located throughout body except brain. Indicate danger, injury, or disease. Thermoreceptors – located in skin, body core, and hypothalamus. Detect temperature changes. Mechanoreceptors – located in skin, skeletal muscles, sound and motion. Sensitive to touch, pressure, stretching of muscles, sound, and motion. Chemoreceptors – located in nose and taste buds. Sensitive to chemicals in external environment. Photoreceptors – located in eyes. Sensitive to light.
DISORDERS OF THE NERVOUS SYSTEM Multiple sclerosis (MS) – It is a chronic disease affecting more women than men often leading to progressive neurological deterioration and ataxic paraplegia. Lesions occur in all parts of the CNS white matter appearing gray and translucent. Some of the more prominent structures affected are the medial longitudinal fasciculus and the optic tract and chiasm. Damage to the neurons in these structures can lead to optic neuritis (with complete loss of vision in one eye), diplopia (double vision) and problems coordinating eye and head movements. Onset of the disease is usually between the ages of 20 and 40 years of age.
DISORDERS OF THE NERVOUS SYSTEM Epilepsy is a brain disorder in which a person has repeated seizures (convulsions) over time. Seizures are episodes of disturbed brain activity that cause changes in attention or behavior. Occurs when permanent changes in brain tissue cause the brain to be too excitable or jumpy. The brain sends out abnormal signals. Epilepsy seizures usually begin between ages 5 and 20, but they can happen at any age. There is no cure, but it is treatable.
SKELETAL SYSTEM Consists of Bones, Cartilage, Ligaments, and Tendons. Supports the body, protects internal organs, allows movement, stores mineral reserves, and provides a site for blood cell formation.
SKELETAL SYSTEM There are 2 types of skeletons. The axial and appendicular skeletons. Axial Skeleton – supports the central axis of the body. Consists of the skull, sternum, ribs, and spine. Appendicular Skeleton – Consists of the bones of the arms, legs, pelvis, and shoulder.
BONES They support and shape the body. Protect internal organs. Provide a system of levers on which muscles act to produce movement. Contain reserves of minerals, mainly calcium salts. Bones are a site of blood cell formation. 206 bones in the human body. Are a solid network of living cells and protein fibers that are surrounded by deposits of calcium salts.
STRUCTURE OF BONES Surrounded by a tough layer of connective tissue called the periosteum. Beneath the periosteum is a thick layer of compact bone. Compact bone is dense, but far from solid. Running through compact bone is a network of tubes called Haversian canals that contain blood vessels and nerves. Inside the outer layer of compact bone is a less dense tissue known as spongy bone. Found in the end of lone bones and middle of short.
STRUCTURE OF BONES Within bones are cavities that contain soft tissue known as bone marrow. There are 2 types of bone marrow: Yellow and Red. Yellow marrow is made up of primarily fat cells. Red marrow produces red blood cells, some kinds of white blood cells, and cell fragments known as platelets. Cartilage is made of tough collagen and flexible elastin.
JOINTS Where one bone attaches to another. 3 types of joints: Immovable, Slightly movable, and freely movable. Immovable – no movement Slightly movable – small amount of restricted movement. Freely Movable – movement in one or more directions. 4 types: Ball-and-Socket Joint – widest range of movement on any joint. Hinge Joint – back and forth motion. Pivot Joint – one bone to rotate around another. Saddle Joint – one bone to slide in 2 directions.
SKELETAL SYSTEM DISORDERS Arthritis – inflammation of the joint itself. Lesser condition called Bursitis which is inflammation of bursa(small sac of synovial fluid). Osteoporosis – weakening of the bone that can cause serious fractures.
MUSCULAR SYSTEM Movement is the function of muscular system. Includes large muscles and thousands of tiny muscles that help to regulate blood pressure, move food through the digestive system, and power every movement of the body. 3 types of muscle tissue: skeletal, smooth, and cardiac.Skeletal Muscle Smooth Muscle Cardiac Muscle
MUSCULAR SYSTEM Skeletal Muscle – Attached to bone. Cells are large from 1mm – 30cm. Consist of muscle fibers, connective tissues, blood vessels, and nerves. Consciously controlled by the CNS. Smooth Muscle – Not under voluntary control. Found in hollow structures such as the stomach, blood vessels, and intestines. Move food through the digestive tract, and control the way blood flows. Cardiac Muscle – found in just the heart. Shares features with skeletal and smooth muscle. Involuntary muscle.
MUSCULAR SYSTEM A muscle contracts when the thin filaments in the muscle fiber slide over the thick filaments. Skeletal muscles are only useful if they contract in a controlled fashion. Skeletal muscles are joined to bones by tough connective tissue called tendons. Tendons pull on the bones and make them work like levers. Regular exercise is important in maintaining muscular strength and flexibility.
DISORDERS OF THE MUSCULAR SYSTEM Muscular Dystrophy, or MD, is an inherited muscle disease that causes muscle fibers to become incredibly susceptible to harm. Muscles grow progressively weaker, and muscle fiber is replaced with fat and other tissue. Symptoms include lack of coordination, muscle weakness, and a progressive loss of mobility. There is no cure for the disease, but some therapies and medications can help slow its progression. Cerebral palsy is a disorder that impairs a persons motor function, posture, and balance. It occurs when there is damage to the area of the brain responsible for muscle tone, or the amount of resistance in a muscle. A person with cerebral palsy will often have difficulty performing physical tasks, though symptoms vary with the severity of the particular case. Atrophy refers to a state where muscle tissue wastes away, each muscle fiber shrinking in size. This can be caused by muscle disuse or when nerve impulses become ineffective.
INTEGUMENTARY SYSTEM Consists of the skin, hair, nails, and a variety of glands. Serves as a barrier against infection and injury, helps to regulate body temperature, removes waste products from the body, and provides protection against UV rays from the sun. Largest component of the integumentary system is the skin.
THE SKIN Contains several types of sensory receptors. Has many functions, but the most important function is protection. Serves as a gateway through which sensations such as pressure, heat, cold, and pain are transmitted to the nervous system. Made up of 2 main layers – the epidermis and the dermis. Beneath the dermis is a sub layer of fat called the hypodermis and loose connective tissue the help insulate the body.
EPIDERMIS Outer layer of the skin. Has 2 layers. The outer layer comes in contact with the environment and is made of dead cells. The inner layer is made of living cells and undergoes rapid cell division. The cells begin to produce keratin, a tough, fibrous protein. Contains melanocytes. Which are cells that produce melanin, a dark brown pigment that helps to protect the skin from damage by absorbing UV rays. Skin color is made by the number of melanin that is produced and where they are distributed.
DERMIS The inner layer of the skin. Lies beneath the 2 layers of the epidermis. Contains collagen fibers, blood vessels, nerve endings, glands, sensory receptors, smooth muscles, and hair follicles. Contains 2 major types of glands: sweat glands and sebaceous(oil). Sebaceous glands produce an oily secretion called sebum. Sebum helps keep the keratin-rich epidermis flexible and waterproof.
HAIR Covers almost every exposed surface of the body. Hair on the head protects the scalp from UV light and provides insulation from the cold. Hair in nostrils, external ear canals, and eyelashes prevent dirt and other particles from getting into the body. Hair follicles are at the base of the hair and are tubelike pockets of epidermal cells that extend into the dermis. All of the hair except the follicle is dead and filled with keratin.
NAILS Grow from an area of rapid cell division known as the nail root. During cell division, the nail root fills with keratin and produces a tough, platelike nail that protects the tips of the fingers and toes. Grow at an average rate of 3mm per month. Fingernails grow about 4 times as fast as the toenails.
DISORDERS OF THE INTEGUMENTARY SYSTEM Skin Cancer – an abnormal growth of cells in the skin. Caused by excessive exposure to sunlight. The three most common malignant skin cancers are basal cell cancer, squamous cell cancer and melanoma. Treatment is dependent on type of cancer, location of the cancer, age of the patient, and whether the cancer is primary or a recurrence. Acne vulgaris (or cystic acne) is a common human skin disease, characterized by areas of skin with Seborrhea (scaly red skin), Comedones (blackheads and whiteheads), Papules (pinheads), Pustules (pimples), Nodules (large papules) and possibly scarring. Acne affects mostly skin with the densest population of sebaceous follicles; these areas include the face, the upper part of the chest, and the back. Severe acne is inflammatory, but acne can also manifest in noninflammatory forms.
CIRCULATORY SYSTEM Humans have closed circulatory system – means that blood is within a system of vessels. Consists of the heart, a series of blood vessels, and blood.
THE HEART Composed almost entirely of muscle. Inside a protective sac called the pericardium. In the walls of the heart are 2 thin layers of epithelial and connective tissue that surround a thick layer of muscle called the myocardium. The myocardium pumps blood through the circulatory system. The heart muscle contracts about 72 times a minute, pumping about 70mL of blood with each contraction. In 1 year the heart pumps more than enough blood to fill an Olympic-sized swimming pool. An Olympic-sized swimming pool is about 2,000,000L. The heart pumps about 2,649,024L of blood in 1 year.
THE HEART Dividing the right and left sides of the heart is the septum. The septum prevents oxygen-poor and oxygen-rich blood from mixing. There are 2 chambers on each side of the septum. The upper chamber, which receives blood, is the atrium (plural: atria) The lower chamber, which pumps blood out of the heart is the ventricle. Has 4 chambers: 2 atria and 2 ventricles.
CIRCULATION THROUGH HEART Blood enters through the right and left atria and goes to the ventricles. When the heart contracts blood moves in and then out of the ventricles to the body or lungs. Flaps of tissue between the atria and ventricles are called valves. When blood moves from the atria it holds the valves open. When the heart contracts the valves close to prevent blood from flowing back into the atria. There are valves at the exits of the ventricles to keep blood from flowing back into the heart. The valves keep the blood moving in 1 direction.
CIRCULATION THROUGH BODY The heart functions as 2 separate pumps. 3 types of circulation. Coronary – pumps blood only to the vessels on the muscle of the heart. Pulmonary – oxygen-poor blood flows to the right side of the heart and then pumps the blood to the lungs to get oxygen. Systemic – the oxygen-rich blood the flows to the left side of the heart and is pumped to the rest of the body.
HEARTBEAT Each contraction begins in a small group of cardiac muscle cells known as the sinoatrial node (SA node), located in the right atrium. These cells are also known as the pacemaker. The impulse spreads from the SA node to the network of fibers in the atria. It is picked up by a bundle of fibers called the atrioventricular node (AV node) and carried to a network of fibers in the ventricles. When the network in the atria contracts, blood in the atria flows into the ventricles. When the muscles in the ventricles contract, blood flows out of the heart. This 2- step pattern of contraction makes the heart more efficient.
BLOOD VESSELS When blood leaves the left ventricle, it passes through the largest blood vessel in the body, the aorta. The aorta is the first of a series of blood vessels that carry blood on a round trip through the body and back to the heart. Blood flows through 3 types of blood vessels: arteries, capillaries, and veins. Arteries – large vessels that carry blood to the tissues of the body. Are the superhighways of the circulatory system. Except for pulmonary arteries, all arteries carry oxygen-rich blood. Have thick walls that help them withstand the powerful pressure produced when the heart contracts.
BLOOD VESSELS Capillaries – smallest of the blood vessels. Are the side streets and alleys of the circulatory system. The walls of capillaries are only 1 cell thick, and most are so narrow cells have to travel single file through them. The real work of the circulatory system – bringing nutrients and oxygen to the tissues and absorbing CO2 and other waste products from them – is done in the capillaries. Veins – responsible for returning oxygen-poor blood back to the heart. The walls contain connective tissue and smooth muscle. Large veins have valves to keep blood flowing to the heart. Many veins are located near and between skeletal muscle.
BLOOD PRESSURE When the heart contracts it creates a wave of fluid pressure in the arteries. The force of the blood on the arteries’ walls is known as blood pressure. Measured with a sphygmomanometer. A cuff is wrapped around the upper arm and filled with air until an artery is blocked. As the pressure is released, the pulse is listened to with a stethoscope and 2 numbers are recorded off a pressure gauge. The 1st number is the systolic pressure – the force felt in the arteries when the ventricles contract. The 2nd number is diastolic pressure – force of blood in the arteries when the ventricles relax. A typical blood pressure in a healthy person is 120/80.
DISORDERS OF THE CIRCULATORY SYSTEM Atherosclerosis – condition in which plaque builds up on the interior walls of the arteries. Particularly dangerous in the coronary arteries – if one gets blocked the heart can’t receive enough oxygen so the person has a heart attack. People can also experience a stroke – where a bod clot breaks free and gets stuck in one of the vessels leading to the brain. High Blood Pressure – or hypertension forces the heart to work harder, which may weaken and damage the heart muscle and blood vessels. People are more likely to develop coronary heart disease and other diseases of the circulatory system. At risk for heart attack and stroke.
BLOOD SYSTEM The human body contains 4-6 liters of blood. 8% of the total mass of the body. About 45% of blood volume contains cells which are suspended in the other 55% - a straw-colored fluid called plasma. Plasma – is about 90% water and 10% dissolved gases, salts, nutrients, enzymes, hormones, waste products, and plasma proteins. 2 types of cells: red and white blood cells. Red Blood Cells – transport oxygen. Get color from hemoglobin – iron containing protein that binds oxygen to the cells. Most numerous blood cell. Circulate for 120 days before destroyed by liver and spleen.
BLOOD SYSTEM White Blood Cells – or leukocytes do not contain hemoglobin. Red blood cells out number them about 1000 to 1. Known as the “army” of the circulatory system. They guard against infection, fight parasites, and attack bacteria. A special class of white blood cells, known as lymphocytes produce antibodies that are proteins that help destroy pathogens. Platelets – blood clotting is made possible by plasma proteins and cell fragments called platelets. Each fragment of cytoplasm made from a cell in the bone marrow is enclosed in a piece of cell membrane and released into the blood stream as a platelet.
DISORDER OF THE BLOOD SYSTEM Hemophilia – is a genetic disorder that results from a defective protein in the clotting pathway. People with hemophilia cannot produce blood clots that are firm enough to stop even minor bleeding. They must take great care to avoid injury. Fortunately, hemophilia can be treated by injecting extracts containing the missing clotting factor.
LYMPHATIC SYSTEM More than 3 liters of fluid leak from the circulatory system everyday. A network of vessels, nodes, and organs called the lymphatic system collects the fluid that is lost by the blood and returns it back to the circulatory system. This fluid is known as lymph. Ducts collect the lymph and return it to the circulatory system through 2 openings in the superior vena cava. Lymph nodes act as filters, trapping bacteria and other microorganisms that cause disease. Lymph vessels absorb fats and fat-soluble vitamins from the digestive tract and carry them to the blood. The spleen helps to cleanse the blood and remove damaged blood cells from the circulatory system.
DISORDERS OF THE LYMPHATIC SYSTEM Lymphedema - The lymphatic system clears away infection and keeps your body fluids in balance. If its not working properly, fluid builds in your tissues and causes swelling. Lymphoma is a cancer of the lymphocytes. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage of the disease
RESPIRATORY SYSTEM Function is to bring about the exchange of oxygen and CO2 between the blood, the air, and tissues. Consists of the nose, pharynx, larynx, trachea, bronchi, and lungs. Air moves from the nose to a tube at the back of the mouth called the pharynx. The pharynx, or throat. It serves as a passageway for both air and food. Air moves from the pharynx to the trachea, or windpipe. A flap of tissue called the epiglottis covers the entrance of it when you swallow. Air that enters the respiratory system must be warmed, moistened, and filtered to keep the lungs healthy.
RESPIRATORY SYSTEM Come cells that line the respiratory system create a thin layer of mucus. Mucus moistens the air and traps particles of dust or smoke that are inhaled. The cilia sweep the trapped particles and mucus away from the lungs toward the pharynx. The mucus and trapped particles are swallowed or spit out. The Larynx is at the top of the trachea. Contains 2 highly elastic folds of tissue known as the vocal cords. When muscles pull on the vocal cords they vibrate and produce sounds. The ability to speak, shout, and sings comes from these tissues.
RESPIRATORY SYSTEM From the larynx, air passes through the trachea into 2 large passageways in the chest called bronchi (singular: bronchus). Each bronchus leads into one of the lungs. Large bronchus divides into smaller bronchi, which divide into smaller passages called bronchioles. The bronchi and bronchioles are surrounded by smooth muscle that helps support them and enables the automatic nervous system to regulate the size of the passageways. The bronchioles continue to divide until they reach a series a dead cells – millions of tiny air sacs called alveoli (singular: alveolus).
RESPIRATORY SYSTEM Alveoli are grouped in little clusters. A delicate network of thin-walled capillaries surround each alveolus. There are about 150 million alveoli in each healthy lung. The air that is inhaled is about 21% oxygen and 0.4% CO2 Exhaled air has less than 15% oxygen and 4% CO2. Since oxygen dissolves easily there is no need for hemoglobin, but hemoglobin increases the oxygen- carrying capacity of the blood more than 60 times. Without hemoglobin your body would need about 300 liters of blood instead of 4-6 liters.
RESPIRATORY SYSTEM Breathing is the movement of air in and out of the lungs. The lungs are sealed in 2 sacs, called the pleural membranes. At the bottom of the chest cavity is a large, flat muscle known as the diaphragm. When you breath in the diaphragm contracts and the rib cage rises crating more volume in the chest cavity. The upper part of the respiratory system is usually able to filter out dust and other particles that could damage the lungs. Smoking tobacco damages and eventually destroys this protective system.
DISEASES OF THE RESPIRATORY SYSTEM Emphysema – is the loss of elasticity in the tissues of the lungs. This condition makes breathing very difficult. People who have it cannot get enough oxygen to the body tissues or rid the body of excess CO2. Chronic Bronchitis – the bronchi become swollen and clogged with mucus. Even smoking a moderate number of cigarettes on a regular basis can cause chronic bronchitis. Affected people often find simple activities, such as climbing stairs, difficult.
DIGESTIVE SYSTEM Calorie – is equal to 1000 calories(the amount of heat need to raise the temperature of 1g of water by 1 degree Celsius is 1 calorie.) Average amount of Calories needed per day for a female is 2200, for a male is 2800. The nutrients that the body needs are water, carbohydrates, fats, proteins, vitamins, and minerals. Every cell in the body needs water because many of the body’s processes, including chemical reactions take place in water.
DIGESTIVE SYSTEM Carbohydrates – are simple and complex. The main source of energy for the body. Fats – or lipids, body needs essential fatty acids to produce cell membranes, myelin sheaths, and certain hormones. Help body absorb vitamins. Proteins – supply raw materials for growth and repair of structures such as skin and muscle. Insulin and hemoglobin are just 2 examples of proteins. Vitamins – are organic molecules that help regulate body processes, often work with enzymes. Examples are vitamins A, D, E, K, C, B1, B12, B6. Minerals – inorganic nutrients that the body needs, usually in small amounts. Examples are calcium, iron, and magnesium.
DIGESTIVE SYSTEM Includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. Several major accessories including the salivary glands, pancreas, and liver add secretions to the system. Function of the system is to help convert foods into simpler molecules that can be absorbed and used by the cells of the body. Mouth – contain the teeth and saliva. Teeth do much of the work of mechanical digestion by cutting, tearing, and crushing food into small fragments. Saliva helps to moisten the food and make it easier to chew. Contains an enzyme called amylase that breaks down the chemical bonds in starches and releases sugars.
DIGESTIVE SYSTEM Esophagus – during swallowing, the combined actions of the tongue and throat muscles push the chewed food, called the bolus, down the throat. When you swallow, a flap of connective tissue called the epiglottis closes the opening of the trachea. This prevents food from blocking the airway. From the throat, the food goes down the esophagus, or food tube, into the stomach. Muscle contractions known as peristalsis, squeeze the food through to the stomach.
DIGESTIVE SYSTEM A thick ring of muscle called the cardiac sphincter, closes the esophagus after food has passed into the stomach and prevents the contents of the stomach from coming back up. Heartburn – is a painful, burning sensation that feels as if it is coming from the center of the chest, just above the stomach. Heartburn is the backflow of stomach acid. It is caused by overeating or drinking to much caffeinated drinks.
DIGESTIVE SYSTEM Stomach – food empties from the esophagus into the large muscular sac called the stomach. Continues the mechanical and chemical digestions. Alternating contractions of the stomach’s 3 smooth muscle layers thoroughly churn and mix the food. Chemical Digestion – the lining of the stomach contains millions of microscopic gastric glands that release a number of substances into the stomach. Some glands produce mucus that protect the stomach lining. Others produce hydrochloric acid, which makes the stomach contents very acidic. The acid activates pepsin, an enzyme that begins the digestion process along with hydrochloric acid.
DIGESTIVE SYSTEM Mechanical Digestion – as digestion proceeds, stomach muscles contract to churn and mix stomach fluids and foods, gradually producing a mixture known as chyme. After an hour or two, the pyloric valve, which is located between the stomach and small intestine, opens and chyme begins to flow into the small intestine. Small Intestine – as chyme is pushed through the pyloric valve, it enters the duodenum. The duodenum is the first of 3 parts of the small intestine, and it is where almost all of the digestive enzymes enter the intestine. Most of the chemical digestion and absorption of the food occurs in the small intestine. As chyme enters the duodenum, it mixes with enzymes and digestive fluids from the pancreas, liver, and the lining of the duodenum.
DIGESTIVE SYSTEM Pancreas – located just behind the stomach. Is a gland that serves 3 important functions. One is to produce hormones that regulate blood sugar. Within the digestive system, it plays 2 key roles. It produces enzymes that break down carbohydrates, proteins, fats, and nucleic acids. Also produces sodium bicarbonate that neutralizes stomach acids, so the enzymes can work. Liver – assists the pancreas. A large organ located just above and to the right of the stomach. Produces bile, a fluid loaded with lipids and salts. Bile dissolves and disperses droplets of fat found in fatty foods. Bile is stored in a small pouchlike organ called the gallbladder.
DIGESTIVE SYSTEM The folded surfaces of the small intestine are covered with fingerlike projections called villi. These folds and projections provide enormous surface area for the absorption of nutrient molecules. When chyme leaves the small intestine it enters the large intestine, or colon. The primary function of the large intestine is to remove water from the undigested material that is left.
DIGESTIVE SYSTEM DISORDERS Peptic Ulcer - when powerful acids of the stomach sometimes damage it’s own lining, producing a hole in the stomach wall. Caused by the bacteria Helicobacter pylori. They can be cured by powerful antibiotics. Diarrhea &Constipation – diarrhea is when not enough water is absorbed from the waste material. Constipation is when too much water is absorbed from the waste material.
EXCRETORY SYSTEM The kidneys play an important role in maintaining homeostasis. They remove waste products from the blood, maintain blood pH, and regulate the water content of the blood and, therefore, blood volume. Kidneys – are located on either side of the spinal column near the lower back. A tube, called the ureter, leaves each kidney, carrying urine to the urinary bladder. The urinary bladder is a saclike organ where urine is stored before being excreted. As waste-laden blood enters the kidney through the renal artery, the kidney removes urea, excess water, and other waste products and passes them to the ureter.
EXCRETORY SYSTEM Kidneys – the functional units of the kidney are called nephrons. Each nephron is a small, independent processing unit. As blood enters a nephron through the arteriole, impurities are filtered out and emptied into the collecting duct. The purified blood exits the nephron through the venule. The mechanism of blood purification involves 2 distinct processes: Filtration and reabsorption. Filtration – filtration of blood mainly takes place in the glomerulus. The glomerulus is a small network of capillaries encased in the upper end of the nephron by a hollow, cup-shaped structure called the Bowman’s capsule. The materials that are filtered from the blood are called the filtrate. The filtrate contains water, urea, glucose, salts, amino acids, and some vitamins.
EXCRETORY SYSTEM Reabsorption – not all of the filtrate is excreted. Most of the material removed from the blood at the bowman’s capsule makes its way back into the blood. Amino acids, fats, and glucose are reabsorbed by the capillaries. Almost 99% of the water is reabsorbed back into the blood. Urine Formation – the material that remains, called urine, is emptied into a collecting duct. Urine which contains urea, salts, and water, among other substances, is primarily concentrated in the loop of Henle. The loop of Henle is a section of the nephron tubule in which water is conserved and the volume of urine minimized.
EXCRETORY SYSTEM DISORDERS Kidney Stones – sometimes substances such as calcium, magnesium, or uric acid salts in the urine crystallize and form kidney stones. When kidney stones block the ureter, they cause great pain. They are often treated with ultrasound waves. The sound waves pulverize the stones into smaller fragments, which are eliminated with the urine.
EXCRETORY SYSTEM An inflammation of the nephrons of the kidneys can result in Nephritis, also sometimes referred to as Bright’s disease. There are many irritants that can cause inflammation, including exposure to turpentine, bichloride of mercy, or even exposure to a cold or following very mild throat infections. Nephritis may also arise after exposure to toxins from scarlet fever, tonsillitis, alcohol or measles. Avoiding fatigue or chilling, or anything that lowers the body’s resistence against infections and colds can decrease the probability of developing Nephritis. There are two kinds of nephritis: acute and chronic. In acute nephritis, the symptoms vary, but generally they involve dropsy in the ankles and eyelids, presence of albumen in the urine, suppression of urine, and sometimes convulsions. In most cases, there is no damage to the kidneys or other body parts, but in very severe cases death can result. When the kidneys suffer permanent damage, nephritis is chronic.
ENDOCRINE SYSTEM Made up of glands that release their products into the bloodstream. These products deliver messages throughout the body. The chemicals that “broadcast” messages from the system are called hormones. Hormones are chemicals released in one part of the body that travel through the bloodstream and affect the activities of cells in other parts of the body. They do this by binding to specific chemical receptors. The cells that contain the chemical receptors are called target cells. A gland is an organ that produces and releases a substance or secretion.
ENDOCRINE SYSTEM Unlike exocrine glands, endocrine glands release their secretions (hormones) directly into the bloodstream. Hormones are classified into 2 general groups: steroid hormones and nonsteroid hormones. Steroid hormones are produced from a lipid called cholesterol. Nonsteroid hormones include proteins, small peptides, and modified amino acids. Except for red blood cells, all cells have been shown to produce small amounts of hormone like substances called prostaglandins. They are modified fatty acids that are produces by a wide range of cells. The Endocrine system is regulated by feedback mechanisms that function to maintain homeostasis.
ENDOCRINE SYSTEM Pituitary Gland – a bean sized structure that dangles on a slender stalk of tissue at the base of the skull. Secretes 9 hormones that directly regulate main body functions and controls the actions of several other endocrine glands. Hypothalamus – above and attached to the back of the pituitary gland. Controls the secretions of the pituitary gland. Thyroid Gland – has the major role in regulating the body’s metabolism. Parathyroid Gland – act to maintain homeostasis of calcium levels in the blood.
ENDOCRINE SYSTEM Adrenal Glands – release hormones that help the body prepare for and deal with stress. Consists of 2 parts. Adrenal Cortex – 80% of the gland. Produces more than 2 dozen steroid hormones called corticosteroids. Adrenal Medulla – the release of its hormones is regulated by the sympathetic nervous system. Pancreas – the hormone producing portion consists of clusters of cells that resemble islands. Clusters are called islets of Langerhans. Each islet includes beta cells that produce insulin, and alpha cells that produce glucagon. Insulin and glucagon help to keep the level of glucose in the blood stable.
ENDOCRINE SYSTEM Reproductive Glands - the gonads are the reproductive glands. The gonads serve 2 important functions: the production of gametes and the secretion of sex hormones. The female gonads – the ovaries – produce eggs and produce the sex hormones estrogen and progesterone. The male gonads – testes – produce sperm and the sex hormone testosterone.
ENDOCRINE SYSTEM DISORDERS Diabetes mellitus – when the pancreas fails to produce or properly use insulin. The amount of glucose in the blood may rise so high that the kidneys actually excrete glucose in the urine. Very high blood glucose levels can damage almost every cell in the body, including the coronary artery. Addisons disease - occurs if the adrenal glands dont make enough of these hormones. A problem with your immune system usually causes Addisons disease. The immune system mistakenly attacks your own tissues, damaging your adrenal glands. Symptoms include: Weight loss, Muscle weakness, Fatigue that gets worse over time, Low blood pressure, Patchy or dark skin. Lab tests can confirm that you have Addisons disease. If you dont treat it, it can be fatal. You will need to take hormone pills for the rest of your life. If you have Addisons disease, you should carry an emergency ID. It should say that you have the disease, list your medicines and say how much you need in an emergency
IMMUNE SYSTEM The function of the immune system is to fight infection through the production of cells that inactivate foreign substances or cells. This process is called immunity. There are 2 categories of defense mechanisms: nonspecific and specific defenses. Nonspecific Defenses – do not discriminate between one threat and another. This includes physical and chemical barriers. First line of defense is to keep pathogens out of the body. Carried out by skin (most important), mucus, sweat, and tears. Second line of defense – when pathogens enter the body and release toxins the inflammatory response is activated. The inflammatory response is a reaction to tissue damage caused by injury or infection.
IMMUNE SYSTEM Interferons – virus-infected cells produce a group of proteins that help other cells resist viral infection. They interfere and block the growth of the virus. Specific Defenses – when the pathogen gets passed the nonspecific defenses. These defenses are called the immune response. A substance that triggers this response is known as an antigen. 2 types of cells that recognize specific antigens are B cells (B lymphocytes) and T cells (T lymphocytes). B cells provide immunity against antigens and pathogens in the body fluids. This is called humoral immunity. T cells provide a defense against abnormal cells and pathogens inside living cells. This is called cell-mediated immunity.
IMMUNE SYSTEM Humoral Immunity - when a pathogen enters the body, its antigens are recognized by a small fraction of the body’s B cells. These B cells grow and divide rapidly, producing large numbers of plasma cells and memory B cells. Plasma cells release antibodies. Antibodies are proteins that recognize and bind to antigens. Are carried in the bloodstream to attack the pathogen that is causing the infection. Cell-Mediated Immunity – the body’s primary defense against its own cells when they have become cancerous or infected by viruses. Important in fighting infection caused by fungi and protists.
IMMUNE SYSTEM Active Immunity – type of immunity produced by the body’s reaction to a vaccine. Vaccination – the injection of a weakened form of a pathogen to produce immunity. They stimulate the immune system to create millions of plasma cells ready to produce specific types of antibodies. Appears after exposure to an antigen, as a result of the immune response. May result from natural exposure (fighting an infection) or deliberate exposure (through a vaccine). Makes its own response antibodies to fight an antigen.
IMMUNE SYSTEM Passive Immunity – when antibodies are produced by other animals and is injected into the bloodstream, the antibodies produce a passive immunity against a pathogen. Lasts for only a short time because the body destroys foreign antibodies. Can develop naturally or deliberately. One kind of natural immunity is when a mother passes antibodies through the placenta or through breast-feeding. Vaccines for leaving to go to another country is an example of passive immunization
IMMUNE SYSTEM DISORDERS Allergies – the most common overreactions of the immune system. Common allergies include: pollen, dust, mold, and bee stings. Antigens that cause allergic reactions are called allergens. When allergy-causing antigens enter the body they attach to mast cells. Mast cells are specialized immune system cells that initiate the inflammatory response. The activated mast cells release chemicals known as histamines which increase blood flow to the surrounding area. They increase mucus production in the respiratory system. The mucus brings on sneezing, watery eyes, runny nose, and other irritations. You have to take anti-histamines which are drugs that are used to counteract the effects of histamines.
IMMUNE SYSTEM DISORDERS Asthma - Some allergic reactions can create a dangerous condition called asthma. It is a chronic respiratory disease in which the air passages become narrower than normal. The narrowing causes wheezing, coughing, and difficulty breathing. Heredity and environment play a role in the onset of asthma. It the leading cause of serious illness among children and can be life threatening. If treatment is not started soon enough or medication isn’t taken properly, it can lead to permanent damage to the lung tissue. Asthma attacks can be triggered by respiratory infections, exercise, emotional stress, and certain medications. There is no cure, but it can be controlled by medications that smooth the muscles around the airways, making it easier to breath.
REPRODUCTIVE SYSTEM Is the formation of new individuals. People can lead a normal life without reproducing. Could be thought of as the single most important system for the continuation of a species. It produces, stores, and releases specialized sex cells known as gametes. Neither the testes or the ovaries are capable of producing active reproductive cells until puberty. Puberty - is a period of rapid growth and sexual maturation during which the reproductive system becomes fully functional. The onset of puberty occurs between the ages of 9 and 15. Begins about one year earlier in females than in males. Puberty begins when the hypothalamus signals the pituitary to produce increased levels of follicle- stimulating hormone(FSH) and luteinizing hormone (LH).
REPRODUCTIVE SYSTEM Male Reproductive System – FSH and LH stimulates cells in the testes to produce testosterone. FSH and testosterone stimulate the development of sperm. The main function of the system is to provide and produce sperm. Before or just after birth the testes drop into the external sac called the scrotum. Within each testis are clusters of hundreds of tiny tubules called seminiferous tubules – are tightly coiled and twisted together. Sperm are produced in these tubules.
REPRODUCTIVE SYSTEM Male Reproductive System - Sperm then moves to epididymis which is a structure in which the sperm fully develop. From the epididymis, sperm are moved into a tube called the vas deferens which extends upward from the scrotum and eventually merges with the urethra the tube that leads to the outside of the body through the penis. About 2 to 6 milliliters of semen are released in an average ejaculation. There are 50-130 million sperm in 1mL of semen.
REPRODUCTIVE SYSTEM Female Reproductive System – primary organ is the ovaries. They produce estrogen. The main function is to produce ova. Also to prepare the female’s body to nourish a developing embryo. Unlike the millions of sperm produced each day in a male, the female on produces one mature ovum, or egg, each month. Egg Development – each ovary contain about 400,000 primary follicles which are clusters of cells that surround each egg. They help an egg mature. Although a female is born with thousands of primary follicles, only about 400 will be released.
REPRODUCTIVE SYSTEM Female Reproductive System Egg Release – after an egg has fully matured it is released in a process called ovulation. The follicle breaks open, and the egg is swept from the opening of the ovary in the fallopian tubes. The egg moves from the fallopian tubes after a few days, to the uterus. The lining of the uterus is ready to receive a fertilized egg. The Menstrual Cycle – after puberty, the female body goes through a complex series of events that lasts about 28 days. During the cycle, an egg develops and is released from an ovary. The menstrual cycle has 4 phases: follicular phase, ovulation, luteal phase, and menstration.
REPRODUCTIVE SYSTEM Follicular Phase – as a follicle develops, the cells surrounding the egg enlarge and produce increased amounts of estrogen. The estrogen level rises dramatically and the lining of the uterus thickens in preparation for a fertilized egg. The development of an egg in this stage takes about 10 days. Ovulation – shortest phase lasting about 3 to 4 days. The release of hormones causes the follicle to rupture, and a mature egg is released in one of the fallopian tubes.
REPRODUCTIVE SYSTEM Luteal Phase – the egg moves through the fallopian tubes and the cells of the ruptured follicle changes its color to yellow and is now known as the corpus luteum. It continues to release estrogen but also begins to release progesterone. In the first 14 days of the cycle, the increase of estrogen levels stimulate cell growth and the lining of the uterus thickens. Progesterone finishes the process by stimulating the growth and development of the blood supply and surrounding tissue. In the fist 2 days of this phase, the chances of an egg fertilizing is the greatest. Menstruation – the egg will pass through the uterus without implantation and the corpus luteum will disintegrate. The lining of the uterus will detach from the wall and the tissue and blood goes through the vagina. This phase lasts 3 to 7 days.
REPRODUCTIVE SYSTEM Fertilization – is the process of a sperm joining an egg. The sperm and egg fuse together to form a single diploid (2N) nucleus. A diploid cell contains a set of chromosomes from each parent cell. A fertilized egg is called a zygote. To prevent more than one sperm from attaching to the egg, the egg releases the granules below its surface to form a barrier around the egg. Development – 3 stages of early development: implantation, gastrulation, and neurulation. Implantation – 6-7 days after fertilization, the blastocyst attaches itself to the uterine wall. The embryo secretes enzymes that digest a path into the wall. The specialization process is called differentiation, is responsible for the development of the body’s tissues.
REPRODUCTIVE SYSTEM Gastrulation – the blastocyst gradually sorts itself into 2 layers, which then gives rise to 3 layers. The 3rd layer is produced by a process of cell migration known as gastrulation. Forms the 3 layers: ectoderm, mesoderm, and endoderm. These layers are the primary germ layers, because all the organs and tissues form from them. Neurulation – the development of the nervous system. Placenta – formed by the chorionic villi and uterine lining. Is the connection between the mother and developing embryo. Is the embryo’s organ of respiration, nourishment, and excretion. After 8 weeks of development, the embryo is called a fetus. After 3 months, most of the organs and tissues are developed.
REPRODUCTIVE SYSTEM DISORDERS Sexually Transmitted Diseases (STD) – infect millions of people each year and accounting for thousands of deaths. The most common is chlamydia. Puts females at risk of infertility due to damage of the reproductive system. Other STDs are syphilis, which can be fatal, and gonorrhea, which is easily spread by intercourse. STDs can be caused by bacteria and viruses. Viral infections cannot be treated with antibiotics. Ovarian Cancer - is the fifth most common cancer among women, and it causes more deaths than any other type of female reproductive cancer. The cause is unknown. Symptoms are often vague such as: bloating or swollen belly area, Difficulty eating or feeling full quickly, Pelvic or lower abdominal pain; the area may feel "heavy" to you (pelvic heaviness), Abnormal menstrual cycles, excessive hair growth that is coarse and dark, Sudden urge to urinate, Needing to urinate more often than usual. Surgery is used to treat all stages of ovarian cancer. Chemotherapy and radiation are also used.