biology final

• tendon: a fibrous connective tissue that attaches muscle to bone.
• ligament: a fibrous connective tissue that attaches bone to bone
• saddle joint: allows for flexion ,extension ,and other movements but very minimal rotation and an example is the thumb joint.
• ball and socket joint: freely moving joint that can rotate on any axis. examples are the hip and shoulder
• condyloid joint: allows circular motion , flexion , and extension. an example is the wrist joint
• gliding joint: move against each other on a single plane. an example is the wrist and ankle
• hinge joint: move on just one axis and an example is the elbow and finger joint
• isometric contraction: the muscle contracts but stays the same length
• isotonic contraction: the muscle changes length as it contracts
• concentric contraction: the muscle shortens while it contracts
• eccentric contraction: the muscle lengthens when it contracts
• in an antagonistic muscle pair as one muscle contracts the other muscle relaxes or lengthens. an agonist muscle always preforms the contracting movement , while the antagonistic muscle serves as the counter muscle , relaxing and often balancing the movement of the agonist muscle
• epidermis: it is the first barrier in the line of defense and responsible for the skin color
• dermis: it is the thickest layer and it gives the skin its structure and resilience. it contains nerve endings , sweat glands , blood vessels , and hair follicles
• hypodermis: insulates the body and stores energy
• sweat glands: maintain body tempurature
• sebaceous glands: produce oil that prevents our hair and skin from drying and inhibits bacteria
• ceruminous glands: produces earwax
• mammary glands: produces milk
• skin burns are tissue damage that result from heat , overexposure to the UV light or chemicals (gasoline , paint) or electrical contacts.
• first degree burn: damages the epidermis , causes minimal skin damage , heals from 7-10 days without scaring
• second degree burn: damages the epidermis and the dermis , causes a moist wound and might form blisters , takes three or more weeks no heal (no scaring)
• third degree burn: the most severe. it affects the dermis and the epidermis and reaches the fat layer beneath the skin causing damages to bones , tendons , and nerves. (scaring occurs)
• nail plate: the outer portion of the nail unit , formed by layers of keratin. it forms a hard yet flexible , translucent plate.
• nail folds: skin that surrounds and protects the nail plate
• nail structure: the cuticle is a layer of clear skin located along the bottom edge of your finger or toe , which is called the nail bed, the cuticle protects new nails from bacteria when they grow out from the nail root.
• how nails grow: nail matrix grows at the bottom of the nail, nail bed grows at the top of the nail
• arthritis is a disease in which joints become irritated or inflamed , such as when cartilage in joints is damaged or wears away.
• osteoporosis: causes bones to weaken and become brittle. Osteoporosis can change a persons skeleton and cause fractures.