28
Chapter 20 Bones and Muscles

Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Embed Size (px)

Citation preview

Page 1: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Chapter 20

Bones and Muscles

Page 2: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

The Skeletal System

The skeletal system consists of two broad divisions:

1. The axial skeleton

2. The appendicular skeleton

Page 3: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Axial Skeleton

The eighty bones that make up the head and spine:

Bones of the skullHyroid – bone of neckVertebrae – bones of

neck and backboneSternum – breastboneRibs

Page 4: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Appendicular Skeleton

Bones on the appendages (arms and legs)

Bones of the hips and shoulders.

Page 5: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Bones of the Head

The skull is divided into two parts:

1. Cranium

2. Facial bones

Page 6: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Cranial Bones

The cranium is made of eight bones tightly formed:

Frontal bone (forehead)

Parietal bone (top of head)

Temporal Bone (sides of head)

Occipital Bone (back of head)

Page 7: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Facial Bones

Includes 14 Bones:

Serve as the framework of the face and jaw

Two maxillary bones – serve as attachment for upper teeth

Palatine bones – form the roof of the mouth

Mandible – ONLY MOVABLE bone of skull

Page 8: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Facial Bones

The smallest bones of your body are found in your ears…

The Malleus (hammer)

The Stapes (stirrup)

The Incus (anvil)

Page 9: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Bones of the Spine

Regions of the vertebral column:

1. Cervical vertebrae (top 7)2. Thoracic vertebrae (next 12)3. Lumbar vertebrae (next 5)4. Sacral vertebrae

a) (next 5, fused in adults - sacrum)b) (last 4, fused in adults – coccyx)

Page 10: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Bones of the Chest

Thoracic Cage:

includes ribs and sternum

Page 11: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Classification of Bones

Bones are classified into four categories:

1. Long bones

2. Short bones

3. Flat bones

4. Irregular bones

Page 12: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Design of the Bone

A long bone (like a femur) has a shaft known as the diaphysis and bulged ends known as epiphysis.

The bone is enclosed in a protective sheath called periosteum (has blood vessels in it).

Page 13: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Engineered for Strength

• Outer shell is strong and dense –compact bone

• Inside is lightweight, porous tissue – spongy bone

it looks “spongy”, but it is hard• Inside the porous spongy bone is the red

marrow (produces blood cells)• Inside the center is the medullary cavity – has

red marrow in young children and yellow marrow in adults.

Page 14: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Maintenance and Restoration

• Bones are self repairing, self maintaining, self modifying.

• Two types of cells maintain the bones:

1. osteoclasts – remove old material to make room for new in the Haversian canals

2. osteoblasts – construct new fibers and crystals

Page 15: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Muscles

There are two major types of muscles:

1. Voluntary Muscle You have

control of these muscles.

2. Involuntary MuscleYou do not have

conscience control of these muscles.

Page 16: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Skeletal Muscle

• You have voluntary control over skeletal muscle

• The primary function of these over 600 muscles is to move the skeleton.

• These muscles are made up of individual cells known as muscle fibers.

• Each skeletal muscle is composed of thousands of these muscle fibers.

Page 17: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Skeletal Muscle

• These muscle fibers give skeletal muscle a striped, or striated appearance….

• Because of this, skeletal muscle is also called striated muscle.

• Most skeletal muscle is attached to bone with tendons.

Page 18: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Skeletal Muscle

• Muscle on the face is attached directly to the bone.

• Skeletal muscle is designed to move quickly and powerfully.

Page 19: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Smooth/Visceral Muscle

• Smooth muscle consist of shorter, wider cells in a looser arrangement.

• Smooth muscle is specialized for relatively slow, powerful, and prolonged contractions.

• It adjusts the tension in the walls of blood vessels.

• It controls the organs of the digestive system.

• It controls the lens of your eye.

Page 20: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Cardiac Muscle

• Cardiac muscle is found only in the heart.

• It is designed to contract over and over without tiring.

Page 21: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

The Design of Skeletal Muscle

Fiber bundles and connective tissue:

The skeletal muscle is encased in a tough, translucent sheath called the fascia. It functions to bind the muscle together.

At the end the fascia tapers into strong tendons that hold the muscle to bone.

Page 22: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

The Design of Skeletal Muscle

• The muscle cells are called muscle fibers.

Page 23: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Structure of Muscle Cells

• A muscle cell is just like other cells with a cell membrane.

• However, they have more than one nuclei and more than the usual number of mitochondria.

• Myofibrils extend the length of the muscle cells.

• A single muscle cell has dozens or hundreds of myofibrils.

Page 24: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Structure of Muscle Cells

• Each myofibril is composed of millions of overlapping protein fibers arranged in repeating units called sarcomeres.

• The sarcomeres give the skeletal muscle their striated appearance.

• They are composed of thick Myosin filaments and thin actin filaments.

Page 25: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Structure of Muscle Cells

• When the muscle contracts, the myosin and actin work to shorten the cell.

• Each myofibril is surrounded by an extensive network of pipes and reservoirs called sarcoplasmic reticulum.

Page 26: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Structure of Muscle Cells

• Addition pipes called transverse tubules connect the sarcoplasmic reticulum to the cell membrane.

• Both of these trigger the myofibril to contract.

Page 27: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

Nerve Impulse Reception

• Muscle contractions are triggered by your nervous system.

• The point at which the nerve attaches to a muscle cell is called neuromuscular junction.

Page 28: Chapter 20 Bones and Muscles. The Skeletal System The skeletal system consists of two broad divisions: 1.The axial skeleton 2.The appendicular skeleton

The End