The Human BodySkeletal, Muscular &

Integumentary Systems

Textbook Chapter 13Review 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 breakthrough skin

• Compound fracture – breaksthrough skin

• 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

• Widest range of movement• Ex. hips/shoulders

– Pivot• Rotation• Ex. neck/head

– Hinge• Back-and-forth movement

(door hinge)• Ex. knee/elbow

– Gliding•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