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Lecture 5

Skeletal and Muscular Systems

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Skeletal and Muscular Systems

1. Skeletal System

– Bones

– Cartilage

– Ligaments & Tendons

– Joints

2. Muscles

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Physical Activity

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Skeletal System

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Functions of Skeleton

Support of the body

Functions of Bones

Protection of soft organs

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Functions of Bones

Movement due to attached skeletal muscles

Functions of Bones

Storage of minerals and fats

Blood cell formation

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The Skeletal System

• Parts of the skeletal system

• Bones (skeleton)

• Joints

• Cartilages

• Tendons and Ligaments

Bones of the Human Body

The adult skeleton has 206 bones

At birth, humans have about 300 bones

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Fun Fact

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Dinosaurs have approximately the same number of

bones as a human does…200

Fun Fact

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Dog has 321

Python has about 1800

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Bones of the Human Body

Two basic types of bone tissue

Compact Bone - dense

Homogeneous

Bones of the Human Body

Two basic types of bone tissue

Spongy Bone – not as dense as compact bone

Small needle-like pieces of bone

Many open spaces

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Bone Marrow

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Bone marrow is a semi-solid tissue which may be

found within the spongy portions of bones.

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Bone Marrow

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Bone Marrow – Primary function is blood cell

formation

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5 Types of Bones

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5 Types of Bones

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1. Long Bones

Femur can withstand up to 4 tons of pressure!

5 Types of Bones

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2. Short Bones

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5 Types of Bones

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3. Flat Bones

5 Types of Bones

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4. Sesamoid Bones - a small independent bones or

bony nodules located in a tendon where it passes over an

angular structure

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5 Types of Bones

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5. Irregular Bones

Bone is a living tissue!

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Types of Bone Cells

Osteocytes

− Mature bone cells

Types of Bone Cells

Osteoblasts

− Bone-forming cells

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Types of Bone Cells

Osteoclasts

– Bone-destroying cells

– Breaks down bone remodeling and release of calcium, phosphorus, etc.

Bone is a dynamic tissue

Bone remodeling is a process by both osteoblasts and osteoclasts

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After you break a bone…

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Cartilage - a strong, flexible fibrous tissue

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Cartilage - found throughout the body.

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Tendons

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A flexible but inelastic cord of strong fibrous

collagen tissue (proteins) attaching a muscle

to a bone.

Ligaments

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A short band of tough, flexible fibrous

connective tissue which connects two bones or

cartilages or holds together a joint.

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Joints of the Body

• Joint - The junction where two bones meet, also

known as a bony articulation.

• 4 different types…

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Joints of the Body

1. Movable joint, Ball and Socket joint…

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Joints of the Body

2. Movable Joint, Hinge Joint…

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Joints of the Body

3. Joint with Limited Movement…

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Joints of the Body

4. Immovable Joint…

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The Skeletal System

• Divided into two divisions

• Axial skeleton- skull, spinal column

• Appendicular skeleton – limbs and girdle

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Axial Skeleton Appendicular Skeleton

The Axial Skeleton

Forms the longitudinal part of the body

Divided into three parts

Skull

Vertebral Column

Rib Cage

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Axial Skeleton -Skull

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Skull Anatomy

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Axial Skeleton – Spinal Column

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Axial Skeleton – Rib Cage

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The Axial Skeleton

• Includes the bones of limbs and bones that

anchor them to the axial skeleton

- pectoral girdle (clavicle, scapula)

- upper limbs (arms)

- pelvic girdle (sacrum, coccyx)

- lower limbs (legs)

Appendicular skeleton

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Muscular System

The Muscular System

• Muscles are responsible for all movement of the

body

• There are three basic types of muscle

– Skeletal

– Smooth

– Cardiac

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Did you know that ?

- more than 50% of body weight is

muscle !

- And muscle is made up of proteins

and water

Info About Muscles

• Only body tissue able to

contract

• create movement by

flexing and extendingjoints

• Body energy converters

(chemical energy to

mechanical energy)

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3 Types of Muscles

Skeletal Muscle

• Found in the Limbs

• Voluntary- subject to conscious control

• Produce movement, maintain posture,

generate heat, stabilize joints

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Smooth Muscle• Spindle shaped

• Involuntary- no conscious control

• Found mainly in the walls of hollow organs

Smooth Muscle

• Lines walls of viscera

• Found in longitudinal or circular arrangement

• Alternate contraction of circular & longitudinal muscle in the intestine leads to peristalsis

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Cardiac muscle

• Main muscle of heart

• Heart muscle cells

behave as one unit

• Heart always contracts

to it’s full extent

• Contracts involuntarily

and rhythmically

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