The Human Body Skeletal, Muscular & Integumentary Systems Textbook Chapter 13 Review Book Topic 1

Structure of the Skeletal System 206 bones in the human body Two divisions: Axial ~ skull, vertebral column, ribs and sternum Appendicular ~ bones of shoulders, arms, hands, hips, legs and feet

                                                            

Types of Bones Connective tissue classified as short, long, flat or irregular Compact ~ dense/strong for strength and protection Spongy ~ contains cavities that contains bone marrow in the center of short or flat bones

Bone marrow Red ~ produces red and white blood cells Arm, leg, rib, vertebrata, and pelvis bones Children’s bones have more than adult bones (only 21% left by age 21) Yellow ~ stores fat

Bone Function Support Protection Movement Storage Blood cell formation

Bone Formation Composed of cartilage in embryos During fetal development they form into osteoblasts (bone forming cells) Ossification leads to the formation, growth and repair of bones Does not occur in the tip of your nose, between vertebrate discs, and lining of joints

Bone Repair Simple fracture – doesn’t break through skin Compound fracture – breaks Stress fracture – thin crack in bone

When a bone is fractured, repair happens immediately Endorphins (chemicals which act as natural pain killers) flood the area of injury temporarily Area becomes swollen which lasts for 2-3 weeks Blood clots form within 8 hours New bone begins to form as cartilage (weak)

Three weeks later, spongy bones surrounds break Stronger, compact bone forms Splints/casts help hold bones in place while healing Age, nutrition, location and severity of break influence healing 4/6 weeks to 6 months

Joints Occur where two or more bones meet Can be classified based on movement and shape (except bones of skull) Not all joints are moveable Ligaments – bands of connective tissue which attach two bones together

Types: Ball-and-Socket Pivot Hinge Widest range of movement Ex. hips/shoulders Pivot Rotation Ex. neck/head Hinge Back-and-forth movement (door hinge) Ex. knee/elbow

Gliding Sutures Side-to-side movement Back-and-forth movement Ex. wrists, ankles, vertebra Sutures Non-moveable Skull joints (22 bones)

Muscular System Consists of groups of fibers or muscle cells bound together Classified according to their structure and function Tendons – attach muscle to bone

Types of Muscle Smooth Involuntary muscles which cannot be controlled consciously Ex. organ muscles: stomach, bladder, intestines, uterus

Cardiac Involuntary muscle of the heart Arranged in a web to allow for muscle contraction Striated with light and dark bands with many nuclei

Skeletal Majority of muscles in the body Muscles attached to bones Voluntary movement which is consciously controlled Striated

Integumentary System Organ system that covers and protects the body Main organ: skin Tissue types: Epithelial tissue Connective tissue Muscle tissue Nerve tissue

Epithelial tissue covers the body surfaces Connective tissue provides support and protection Muscle tissue is involved with movement Nerve tissue forms the body’s communication network

Functions of Integumentary System Temperature Regulation Vitamin Production Protection Senses

Structure of the Skin Epidermis Outer layer of skin 10-30 cells thick Outer cells contain keratin Waterproof, protective protein layer on top of skin Melanin Pigment that absorbs light energy Amount produced influences skin color

Dermis Layer below epidermis 10-40 times thicker than epidermis Consists of connective tissue to prevent skin from tearing and gives it elasticity Contains nerve cells, muscle fibers, sweat glands, oil glands, and hair follicles Deeper layer stores fat to help retain body heat

Hair and Nails Contain keratin Develop from epithelial cells Hair grows out of hair follicles Nails grow 0.5 to 1.2 mm per day