Presentation on theme: "Skeletal System What makes up the skeletal system? –Bones (& connective tissue) made up of living and nonliving material –Cartilage-no blood vessels –Tendons."— Presentation transcript:
Skeletal System What makes up the skeletal system? –Bones (& connective tissue) made up of living and nonliving material –Cartilage-no blood vessels –Tendons (attach muscle to bone) –Ligaments (attach bone to bone)
Functions Support and shape Protect organs Provide a system of levers (mov’t) Mineral reserve (Ca & P) store fat Site of blood cell formation (marrow)
Bone Marrow Yellow Marrow –Blood vessels –Nerve cells –Fat cells Red Marrow –Produces red blood cells (erythrocytes) –Produces white blood cells (leukocytes- lymphocytes) –Other elements (platlets-thrombocytes)
Development of Bone Chondrocytes- cartilage cells Cartilage- connective tissue. Found where needed. (nose, ears, voice box, windpipe, ends of bones, ribs) 3 Types of cartilage: –Elastic-flexible (ears) –Hyaline-loose collagen, not too strong (end of nose, ribs, bones, joints) –Fibrocartilage- densely packed, tough (Intervertebral disks, pubis symphasis)
Development continued Replacement bone- cartilage model of what bones will look like –Newborns are mostly cartilage –Cartilage is replaced by bones about two months in utero. –Ossification is the process where cartilage is replaced by bone. Mineral deposits lay down near center Bone tissues form OSTEOCYTES (bone cells) that replace cartilage.
Anatomical Planes Sagittal- separates Right and Left Frontal- separates Front and Back Transverse- separates Top and Bottom
How do bones move? Bones move by using a system of levers called JOINTS. Joints- –Where two bones meet –Permit movement –Hold bones in place
Joints Immoveable Joints- –Fixed, allow no movement –skull Slightly Moveable Joints- –Small amount of mov’t –Tibia, fibula, and vertebral column Freely Moveable Joints- –Most joints, ends of bones covered with cartilage –Synovial fluid-thin lubricant over joint –Small pockets of synovial fluid (BURSAE)
Freely Moveable Joints Ball and socket- permits circular mov’t: widest range of motion. –(shoulder and hip) Hinge-back and forth mov’t –(Elbow and knee) Pivot- allow rotation around a fixed point –(atlas and axis) and (radius and ulna)
More Freely Moveable Joints Gliding-Sliding of one bone over another –(Wrist, ankles, clavicles) Saddle-permit movement at 2 planes –(Thumb) Ellipsoid- hinge type mov’t in 2 directions –Fingers to palms and toes with soles.
Muscles Muscles make up ½ of the body’s weight. Mrs. Hinzman in College
Three types of Muscles Skeletal- voluntary –Attaches to bone Smooth- involuntary –Alimentary canal, keeps eyes focused, arteries Cardiac-involuntary –Found only in the heart
Muscles Skeletal –Striated, multinucleated Smooth –Spindle shaped, single nucleus Cardiac –Striated, single nucleus
Muscle Tone Muscles are kept in partial contracted state by a steady flow of nerve impulses from the spinal cord. If muscles lose nerve supply, what happens? –Shrinks, muscles lose about 2/3 bulk w/in months –Muscles can repair themselves
Origin –Muscle attachment on stable bone Insertion –Muscle attaches to one or more moveable bones.
Muscle STRENGTH Depends on muscle shape: –Most powerful muscle is where? Spine-maintain posture and lifting –Hand muscles-dexterity –Eye (sphinctor) muscles- dialate, open and close like a valve.
How Do Muscles Contract? Myosin- thick filaments Actin- thin filaments Cross Bridges- knoblike projections that form in each myosin filament when actin and myosin come together.
Sliding Filament Theory 1. When muscles contract, CROSS BRIDGES move pulling the ACTIN and MYOSIN passed each other. 2. After CROSS BRIDGES move as far as it can, they release ACTIN to its natural position. Muscle work against each other (antagonist) Flexing-makes angle small (biceps) Extending-makes the angle bigger (triceps)
The Return of ATP ATP –Gives us energy (how do we get ATP in our bodies?) –Aerobic process (required oxygen)-cellular respiration –Anaerobic process (no oxygen needed)- fermentation (glycolysis) –ATP makes and breaks contractions of actin and myosin. (enzyme, acetylcholinesterase, terminates a muscle contraction)
Questions??? Do muscles push, pull, or do both? What would take longer to heal? –Muscle, tendon, or ligament. Why?
Integument (SKIN) System Skin is the largest organ in the body Self repairing How does skin repair itself? What process occurs? What pigment determines the color of skin?
Functions Protect body from injury or infection Helps regulate body temperature – How? Removes waste – How? Protects from UV rays –How?
EPIDERMIS –Outer most layer of skin, NO BLOOD VESSELS, but has NERVES –Cells undergo rapid division (MITOSIS) –As new cells are produced, old cell are pushed to surface become Keratin –Keratin is tough fibrous protein that forms hair, nails, and calluses –Keratin waterproofs our skin –New outer layer of skin is renewed every 14-28 days
DERMIS Inner most layer under the epidermis Contains blood vessels and nerves, sense organs, smooth muscle, and hair follicles
Hot or Cold? What does our body do to conserve heat? –Blood vessels constrict to limit the heat lost…keeps us warmer What does our body do to cool down? –Blood vessels open up, increases heat loss
Glands in Dermis 1. Sweat gland- –Produces sweat (salt and water) –Nerve impulses stimulate when body temp. rises 2. Sebaceous gland- –Produces oily secretion called SEBUM –Keeps skin flexible and waterproof
Hypodermis Layer beneath the dermis Composed mostly of fat –Insulates the body –Protects –Energy storage