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The Human Body Chapter 19 Skin SkeletalSystem and Muscular System 19 1 Human Body Organization Cells Tissues Organs Organ systems. Organism Review parts of the cell the basic unit of Tissue a group of cells that work togetherto perform a specific function There are 4 main types of tissue in the human. Epithelial tissue Connective tissue Muscle tissue Nervous tissue Epithelial tissue. Covers the outside of the body and linesstructures inside the body Cells are closely packed to provide aprotective barrier for the body Connective tissue. Tendons ligaments bones and blood Holds together other tissues Cells are loosely packed Muscle tissue Muscles around bones and in organs . Allows movement Nervous tissue Gathers and transmits information throughoutthe body senses and responds A group of tissues working together to.perform a specific function Organ system A group of organs that work together to carryout one or more body functions Circulatory system. Pumps blood throughthe body bringsnutrients to cells carries wastes awayfrom cells . Skeletal system Supports the body andgives it shape Muscular system Enables the body to. Respiratory system Takes in oxygen fromthe air and gives offcarbon dioxide Digestive system. Takes in food andbreaks it down intousable energy Urinary system Rids the body of liquid.and dissolved wastesand helps balance saltsand water in the body Nervous system Takes in and responds.to information in theenvironment Endocrine system Helps regulate thebody s functions. Immune system Helps the body fight Reproductive system Allows the productionof offspring . 19 2 Skin Skin also known as the integumentary Largest organ of the body 2 square meters Sense organ Covers body and protects it from injury . Regulates body temperature Rids body of wastes Prevents water and blood loss Protects body from disease The skin is made of three layers . Epidermis Outer layer Dermis Middle layer Subcutaneous tissue Deepest layer Epidermis . The outermost layer Replaced every 28 days Made of cells called keratinocytes that producekeratin a protein that makes the skin tough Hair nails feathers claws and horns are alsomade of keratin . Keratinocytes protect deeper cells fromdamage and drying out and keep outmicroorganisms The cells in the epidermis are in layers Old keratinocytes fill up with keratin and get.pushed up by new keratinocytes which areproduced by the innermost layer of theepidermis As the cells get pushed away they are awayfrom the blood supply and die . These cells then flake off and become dust Other cells in the epidermis Melanocytes Produce melanin Melanin The chemical responsible for skin color More melanin darker skin . Melanin is released when the skin is exposed tothe sun causes a tan Protects skin from sun Langerhan s cells Immune cells Dermis the thick middle layer of the skin Contains many different items . Nerve endings Sense of touch Blood vessels Control body temperature Expand to release heat contract to keep heat Sweat glands Control body temperature Sweat evaporates to cool body off . Sweat also removes some wastes from the body More items in the dermis Connective tissue Collagen and elastin fibers Elasticity Hair follicles. Oil glands Keep skin smooth and waterproof andkeep hair from getting brittle Subcutaneous tissue The innermost layer of the skin Contains connective tissue and fat cells . Fat cells insulate the body and conserve heat First degree Just the epidermis Pain Second degree Epidermis and dermis Pain Third degree All three layers of skin No painbecause the nerve endings are destroyed . Skin Cancer Warning Signs The ABCDEs of Melanoma AsymmetryIf you draw a line through this mole the two halves will not match Border.The borders of an early melanoma tend to be uneven The edges may be scalloped orHaving a variety of colors is another warning signal A number of different shades ofbrown tan or black could appear A melanoma may also become red blue or some other color DiameterMelanomas usually are larger in diameter than the size of the eraser on your pencil 1 4.inch or 6 mm but they may sometimes be smaller when first detected EvolvingAny change in size shape color elevation or another trait or any new symptom suchas bleeding itching or crusting points to danger http www skincancer org melano... . Modified skin Mostly keratin Protect the soft tissue at the tips of the Covers the entire body except for palms soles and lips . Mostly keratin Protects eyes and nose from dust Keeps body warm Insulates head Goose Hair follicles Tiny saclike structures in dermisfrom which hair grows . There are 206 bones in the skeletal system Gives the body shape Supports the body Protects organs Allows movement . Stores nutrients Produces blood cells The skeleton is divided into two main Axial skeleton Bones ofthe head neck and.trunk in green Appendicular skeleton Bones of the limbs in Bones to know Sternum. Vertebrae Sacrum Coccyx Bones to know Clavicle. Scapula Humerus Radius Carpal bones Metacarpal bones. Phalanges Bones to know Pelvic girdle Patella Fibula. Tarsal bones Metatarsal bones Phalanges A bone s shape relates to its function Long bones In arms and legs for example . Short bones In fingers and toes for example Flat bones In skull and pelvis for example Irregular bones In backbone and ears for Composition of a bone A bone is made of three. Periosteum Compact bone Spongy bone plus bone marrow inthe middle of long. Periosteum Thin layer that covers the bone Contains blood vessels Compact bone Dense layer underneath theperiosteum Contains blood vessels nervecells osteocytes and minerals calcium and.phosphorous Spongy bone Strong but lightweight Bone marrow Found in the cavity in themiddle of long bones Red bone marrow Produces red blood cells and.some white blood cells Yellow bone marrow Contains mostly fat cells which store energy Bone growth and repair are allowed by twotypes of cells . Osteoblasts Produce bone Osteoclasts Break down bone Bone tissue Formation of bone Bones start out as cartilage in the fetus . Cartilage Soft flexible connective tissue The cartilage gradually changes to bonethrough a process called ossification At birth a person has over 300 bones As we develop some of these bones fuse so.we end up with 208 bones The place where two bones meet There are three classifications of joints Immovable Allow no movement Example Bones in the skull . Slightly movable Allow limited movement Example Bones in the spine Movable Allow movement in one or moredirections Example Bones in the arms and legs . There are four kinds ofmovable joints Ball and socket Allows movement in manydirections Examples Hip and shoulder .Ball and socket joint Gliding Allow bones to slide past each other Examples Wrist and ankle Hinge Allow back and forth movement Examples Elbow knee finger and toe . Pivot Allow bones to twist past each other Example Forearm Ligaments Thick connective tissue that holdsbones together at joints Tendons Attach muscle to bone . 19 4 The Muscular System There are more than600 muscles in your Muscles make up over40 your body mass . Muscles to know Sternocleidomastoid Deltoid Trapezius Pectoralis major. Biceps brachii Triceps brachii Rectus abdominus Muscles to know Sartorius. Gastrocnemius Latissimus dorsi Hamstring group Quadriceps group Gluteus maximus. There are threetypes of muscle Skeletal muscle Attach to bones Long thin cells with.more than one nucleus Striated Hasalternating light anddark bands Pull on bones to allow.voluntary movements Smooth muscle Found in internal Tapered cells with onenucleus Not striated . Is involuntary notunder conscious Cardiac muscle Found in the heart Branched cells with.striations and only one Involuntary Skeletal muscle structure Skeletal muscle fibers are grouped into bundles These bundles contain muscle cells connective.tissue nerves and blood vessels Actin and myosin The proteinsresponsible forcontraction . Gives the musclecell its striatedappearance Muscle cell contraction http www youtube com watch v g... . Motor nerve Connects muscle cells One motor nerve canconnect to many muscle Muscles and movement . Tendon Attaches muscle to bone Skeletal muscles PULL on bones only In order to allow for a full range of motion skeletal muscles are usually found in pairs One muscle moves the bone in one direction and.another moves it in the opposite direction When one contracts the other relaxes and vice versa Melanomas usually are larger in diameter than the size of the eraser on your pencil (1/4 inch or 6 mm), but they may sometimes be smaller when first detected. Evolving. Any change â€” in size, shape, color, elevation, or another trait, or any new symptom such as bleeding, itching or crusting â€” points to danger.