Unit 10 Chapter 34 Protection, Support, and Locomotion

Skin: the Body’s Protection Integumentary System Contains skin and its related parts—hair, nails & glands Functions: Regulates body temperature Receives stimuli from environment Produces vitamin D Protection of underlying tissues

Skin: the Body’s Protection Epidermis: Outer layer of skin, composed of dead, flattened cells Contains Melanin, a pigment that colors the skin & protects cell from damage by radiation

Skin: the Body’s Protection Dermis Inner, thicker portion of the skin Contains blood vessels, nerve endings, hair follicles, sweat & oil glands

Skin: the Body’s Protection Hypodermis (subcutaneous layer) Below the dermis Contains primarily of fat for cushioning & insulation

Bones: the Body’s Support Skeletal System divisions: Axial skeleton Includes the skull, vertebrae, ribs & sternum Appendicular skeleton Includes bones of the arms & legs, and shoulder & hip bones

Bones: the Body’s Support Skeletal system functions: Protection Support Attach muscles Produce blood cells Store minerals

Bones: the Body’s Support Joints Where two bones meet Facilitates the movement of bones in relation to one another

Bones: the Body’s Support Ligaments Connective tissue that attaches one bone to another Tendons Connective tissue that attach muscles to bones

Bones: the Body’s Support Spongy bone Soft bone containing many spaces filled with red marrow Compact bone Dense bone with an inner cavity containing yellow marrow Haversian system Circular area in compact bone containing blood vessels, nerves, and living cells called osteocytes

Muscles for Locomotion

Muscles for Locomotion Smooth muscle Involuntary movement Found in hollow body organs, i.e. stomach, arteries, iris of eye Spindle-shaped cells, non-striated, one nucleus per cell

Muscles for Locomotion Cardiac muscle Involuntary movement Found only in the heart Branching, striated (striped) cells, with one nucleus per cell

Muscles for Locomotion Skeletal muscle Voluntary movement Found attached to bones, i.e. biceps, triceps, hamstrings, etc Long, striated (striped) cells, with many nuclei

Extensor and flexor muscles Click on image to play video.

Muscles for Locomotion Common Skeletal muscles

Muscles for Locomotion Muscle contraction: Muscle fibers (cells) are made up of smaller units called myofibrils Myofibrils contract (shorten) as filaments, called myosin & actin, slide toward one another

Sliding filament model