Lesson 1 Your skin has two main layers which include the epidermis – the outer, thinner layer of your skin, and the dermis – the inner, thicker layer of your skin. The epidermis is made of both dead and living cells. New cells arise to the surface to replace the old ones. Some of the cells in the epidermis produce melanin , the pigment that gives skin, hair and the iris of the eyes their coloring. Melanin determines the color in your skin. The dermis is made up of connective tissue that gives the skin its elasticity, or spongy, flexible quality. Under the dermis is tissue called the hypodermis. Although it is not part of your skin, it attaches your skin to the bone and muscle. Structure of the Skin
Your skin shields you from injury, invasion by pathogens, and the sun’s harmful ultraviolet (UV) rays. Your skin is the main divider between your internal organs and the outside world. It is also waterproof and has a water-holding capacity.
Regulating Body Temperature
Skin keeps body temperature constant. Radiation is a process when tiny blood vessels in the skin enlarge, permitting internal heat to escape. This happens when your body is hot and sweat glands also become active, releasing perspiration, which cools the skin as it evaporates. You conserve body heat as your internal temperature drops because of how the blood vessels narrow.
Enabling you to Sense the World Around you
Skin serves as a means of communication with the outside environment. Nerve endings respond to touch, pain, pressure and temperature.
Skin Care and Problems With the Skin Lesson 1 Some common problems with the skin are as followed:
The skin should be washed every morning and evening with soap and water. A balanced eating style should also be used to promote healthy skin. Everyone needs to bathe, wash, or shower daily to prevent bacteria that causes body odor. Vitamin A also helps with your health and some items that include this are: milk, egg yolks, liver, green leafy and yellow vegetables, and yellow fruits.
Lesson 2 Functions The skeleton provides a strong, stable, and mobile framework on which muscles can act. It also supports and protects your internal organs. Structure Axial skeleton: -includes the 80 bones of the skull, spine, ribs, and sternum -the vertebrae protect your spinal cord -The ribs protect your lungs and heart Appendicular skeleton: -includes the 126 bones of the shoulders, arms, hands, hips, legs and feet Joints
The point at which two bones meet is a joint. Most joints allow a wide range of movement. There are several types of mobile joints:
Ligaments are tough bands of fibrous, slightly elastic tissue that bind the bone ends at the joint. Ligaments also prevent excessive movement of the joint. Tendons are fibrous cords that join muscle to bone or to other muscles.
Calcium is an important mineral found in dairy products essential for building strong bones. Phosphorus is another vital mineral that gives your bones their rigidity. Exercise promotes better blood circulation which increases nourishment to you bones.
Fractures are any type of break in your bone. Some include:
Lesson 3 Functions Without muscles, nothing in your body would work. Muscles pump blood through your body, move food through your digestive system, and control the movement of air in and out of your lungs. Structure The major muscles are: Smooth muscles: the type of muscle concerned with the movements of internal organs Skeletal muscles: the striped, or striated, muscles attached to bones that cause body movements Cardiac muscle: a special type of striated tissue that forms the walls of the heart Care
To maintain muscle tone , you need to keep active and eat nutritious meals.
Myasthenia Gravis: muscles become weak and easily fatigued
Muscular Dystrophy: an inherited disorder characterized by a progressive wasting away of skeletal muscles
Injury-Related Muscular Problems
Muscle strain: a tearing or stretching of muscle fibers as a result of suddenly pulling them too far
Bruise: a discolored area under the skin caused by leakage of blood after an injury
Tendinitis : the inflammation of a tendon
Hernia: a protrusion of an organ or tissue through a weak area in the muscle
Lesson 1 Function Your nervous system controls all your body’s actions and functions. Structure Central Nervous System: receives and analyzes information and initiates responses. Includes the spinal cord and brain. Peripheral Nervous System: gathers information from inside and outside of your body.
The Brain Stem
A 3-inch-long stalk of nerve cells and fibers that connect the spinal cord to the rest of the brain.
Medulla oblongata: the lowest part of the brain stem
Pons: pathway for nerve impulses passing to and from the cerebrum
Midbrain: shortest part of the brain stem
Thalamus: an important relay center for incoming sensory impulses
Hypothalamus: keeps body conditions balanced
Reflex Action A spontaneous response of the body to a stimulus.
Lesson 2 Care of the Nervous System To keep your nervous system functioning well, you need: -Regular exercise -Proper nutrition -Adequate rest and sleep Problems Accidents can damage or destroy nerve tissue Degenerative diseases can destroy nerve tissue in the brain or spinal column. Drug and alcohol use can lead to nervous system disorders. Head Injuries Any direct blow to the head can lead to possible brain injury. A concussion, a temporary disturbance of the brain’s ability to function, is the most common and mildest kind of brain injury. A contusion is more serious though and can result in a coma. Spinal Injuries Injury on the spinal cord can lead to paralysis. An injury at neck level may result in quadriplegia and paralysis is in both the arms and legs. Injury at the chest level or lower affects the legs and lower body. Degenerative Diseases Parkinson’s disease: caused by degeneration of the nerve cells within the brain that modify nerve impulses transmitted from the motor areas of the brain. Multiple sclerosis: the destruction of the myelin sheath that surrounds nerve fibers in the brain and spinal cord. Alzheimer’s disease: causes general mental deterioration Other Disorders Epilepsy: a disorder of the nervous system that is characterized by seizures Cerebral Palsy: a group of nonprogressive neurological disorders that are the result of damage to the brain before birth, during birth, in the newborn period, or in early childhood.
Lesson 3 Structure The principal structures are the endocrine glands which are ductless structures that secrete hormones . Hormones are chemical substances produced by ductless glands that regulate the activities of different body cells. Glands Pituitary Gland: regulates and controls the activities of all other endocrine glands. Thyroid Gland: produces hormones that regulate metabolism-the use of nutrients by the body’s cells-body heat production, and bone growth. Parathyroid Glands: structures that produce parathyroid hormone, which regulates the body’s calcium and phosphorus balance. Adrenal Glands: two glands located on the top of the kidneys. The Pancreas The pancreas is a gland that serves two systems-the digestive and the endocrine. It is located behind the stomach, attached to the first section of the small intestine by a duct that transports its digestive juice to the intestine. The Gonads Of all the endocrine glands, only the gonads are different in males and females. The ovaries (female) and testes (males) are apart of the reproductive system. The ovaries produce and release ova, and the testes produce and release sperm. Gonads play a huge part in the process of the reproductive system which will be discussed in chapter 19.
Most of the disorders are related to the production of too much or too little of hormone. Some disorders include:
Diabetes Mellitus: a disorder in which the pancreas produces too little or no insulin.
Graves’ Disease: an autoimmune disorder in which the thyroid gland becomes overactive and enlarged, producing excessive amounts of thyroid hormones.
Crushing’s Disease: overproduction of adrenal hormones
Goiter: and enlargement of the thyroid gland
If the anterior lobe of the pituitary gland does not produce enough of the growth hormone, a person does not grow. The person’s stature is short although the bones are usually in normal shape.
Chapter 17 The Circulatory and Respiratory Systems
Lesson 1 Functions Your circulatory system maintains an internal environment in which all the calls of you body are nourished. As your heart pumps blood, blood vessels carry oxygen and nutrients to body cells. At the same time another gas carbon dioxide, is carried along with waste matter from your cells and delivered to your lunges and kidneys for removal from the body.
The main parts of the circulatory system are your heart, blood, arteries, veins and capillaries.
The heart- Along with your brain, your heart is the most important part of your body's vital organs. The brain never rests; the muscular pump beats continuously to send blood to the and the rest of the body.
Blood- The fluid that transports all the substances that your body needs to sustain life. Blood delivers oxygen, hormones, and nutrients to the cells and carries away wastes that the cells produce. About 55% of the total volume of blood is made up of plasma the fluid in which the other parts of blood are suspended.
The Lymphatic system Your body's circulatory system is supported by a second network known as the lymphatis system. This system serves to functions. It drains tissue fluid back into the bloodstream, and it fights infection. All body tissues are bathes in watery fluids that comes from the blood. The remainder is carried to the heart through the lymphatic system. The lymphatic system is your second circulatory system. The fluid is circulated through your body’s muscles. Circulatory System
Care of the Circulatory and Lymphatic System Smoking puts added stress on your circulatory system. It increases blood pressure and heart rate by narrowing arteries. Being overweight is linked to high blood pressure and coronary heart disease, so maintaining an appropriate weight is important. Everyone should also have an aerobic exercise 3 times a week for 20 minutes and regular check ups are important too. Lesson 2 Blood Pressure Blood pressure is the force of blood in the main arteries. It rises and falls as the heart and muscles of the body cope with varying demands. When arterial pressure is at its greatest, it is called systolic pressure. When the arterial pressure is at its lowest, it is called diastolic pressure.
Lesson 1 The Digestive System Functions Digestion- the mechanical and chemical breakdown of foods for use by the body’s cells. Absorption- the passage of digested foods from the digestive tract into the circulatory system. Elimination- the expulsion of undigested food or body wastes Structure Digestion begins before you take a bite of food when the aroma of food activates the salivary glands. The Mouth and Teeth The primary function of your teeth is to break food you eat into smaller pieces. Mastication is the process of chewing. Organs That Aid Digestion The Liver The Gallbladder The Pancreas
Good eating habits are the best way to avoid or minimize digestive system problems.
Eat a variety of foods.
Avoid an overabundance of fried foods.
Do not hurry through your meals-eat slowly while sitting down.
Do not wash your food with liquid. Wait until you are finished chewing-swallow, and then take a sip of liquid
Drink plenty of water!
Do not eat when you are under stress.
The Urinary System The chief function of the urinary system is to remove water soluble waste products that result from chemical changes to cells. Urine contains nitrogen and, therefore, would become toxic if allowed to remain in your body. Your bladder is a hollow, muscular organ that acts as a reservoir for urine. Care of the urinary system is to regularly drink fluids and to have a well-balanced eating style. Problems of the Urinary system is Cystitis-a bacterial infection of the bladder that occurs mostly in females and Urethritis- an inflammation of the urethra. Lesson 3
Some of the problems that occur are related to menstruation. Others are related to infertility , the inability of a woman to become pregnant.
Problems Related to Menstruation
Toxic Shock Syndrome
Problems that Can Cause Infertility
Blocked Fallopian Tube
Pelvic Inflammatory Disease
Other Reproductive Disorders
Some other disorders include ovarian cysts and cancers of the reproductive system. About one out of every eight females develop cancer at sometime. Early sexual activity, as well as family history of cervical cancer and other factors, is related to an increased incidence of cervical cancer. A Pap test should be done every one or two years after a woman has reached 18 years of age or has become sexually active.