Skeletal, Muscular, and
Integumentary Systems
Ch. 36
Skeletal System
-The skeletal system has 206 living bones in the average
human body.
Function:
-supports the body
-protects internal organs
-provides for movement
-stores mineral reserves
-blood cell production
-Bones are made up of the elements
phosphorus and calcium.
Two Divisions of the Skeletal System:
1. Axial- skull, vertebral column, and rib cage
2. Appendicular- bones of the arms, legs, pelvis,
and shoulder
Bone Structure
Periosteum- outer layer
Compact Bone- thick solid layer
Haversian Canals- tubes that contain
blood vessels and nerves.
Spongy Bone- found at the tips of long
bones; porous; contains red bone
marrow.
Bone Marrow- center core of bones;
contains yellow bone marrow.
Growth Plate- area of dividing bone cells
in kids and young adults.
Cartilage- connective tissue found at the
tips of bones; layer of protection.
Bone Development
-Human embryos are made of cartilage.
-Cartilage hardens to bone as the ‘birth’ date
gets closer. Process is ossification.
-Some areas of cartilage stay intact throughout
the life of a human.
Types of Bone Cells:
Osteocytes- mature bone cells.
Osteoclasts- break down old bone cells.
Osteoblasts- produce new bone cells.
*Your body continually breaks down old bone
cells and replaces them with new bone cells.
Types of Joints:
Joint- a place where one bone attaches to another
bone.
Types:
1. Immovable (suture, bones in the skull)
2. Slightly Movable (symphysis, bones of
the vertebrae)
3. Freely Movable (ball-and-socket, hinge,
pivot, saddle)
Joints are held together by ligaments.
Skeletal System Disorders:
Inflammation of a Joint
Arthritis
Osteoporosis
Ch. 36.2 Muscular System
Function: movement throughout the body.
Types:
1. Skeletal- moves the bones; voluntary.
2. Smooth- lines internal organs structures in the body;
involuntary.
Examples: lining of the stomach
3. Cardiac- found in the heart; involuntary. Allows for
contraction of the heart.
Muscle Contraction
Muscle Fibers (cells)
Myofibrils
Filaments
Actin & Myosin
Actin and Myosin are proteins that are the basis for all
muscle contraction.
Muscle contraction occurs when ATP (energy) causes the
actin to slide over the myosin.
Muscle Contraction Clip
Diagram of Actin & Myosin Filaments
Neuromuscular Junction
-Point where neurons
make contact with a
muscle cell.
-Neurons release the
neurotransmitter
acetylcholine which
stimulates the release
of Ca2+ within the muscle
fiber.
The Muscle Bone Connection
Skeletal Muscles are connected to bones by
tendons.
Ch. 36.3 The Integumentary System
Functions:
1. barrier for protection against infection and injury.
2. regulate body temperature
3. remove waste products
4. provide protection against UV light (sun)
Layers:
1. Epidermis
2. Dermis
3. Hypodermis
Epidermis
-outer most layer of the epidermis is made up of
dead skin cells.
-inner layer of the epidermis is made up of living
cells.
-contains the protein, keratin. Gives skin its
waterproof ability.
-contains the protein, melanin. Gives skin its
color and protects from UV light.
Dermis
-inner (middle) layer of the skin.
-contains collagen, blood vessels, nerves, glands,
muscles, and hair follicles.
-Two major glands:
1. sweat- helps cool the body
2. sebaceous (oil)- secrete sebum
Hypodermis
-contains adipose (fat)
-functions to insulate and store nutrients
Hair
-made up of keratin
-protects the body and internal structures
-made in hair follicles
-oil glands secrete oil to protect the hair
Nails
-made up of keratin
-nails grow from the nail root
-protects the tips of fingers and toes