P.E - A0S 1 - Chapter 1

Hard

Functions Of Skeletal System

Body movement

Framework

Protection

Mineral Storage

Production of red blood cells

Type Of Bone Tissue

Compact bone, Cancellous bone

Hemoglobin

Protein in red blood cells that transports oxygen around the body

Bones in the body

Types of bones

Short bones (cubical bones)

Long bones (bones longer than their width)

Sesamoid bones (Small bones developed around tendons in some joints)

Irregular bones (no specific structure)

Parts of vertebrae

Cervical (supports the head and neck) - 7 bones

Thoracic (supports ribcage and vertebral column) - 12 bones

Sacrum (pelvis bones) - 5 bones

Coccyx (Bottom of vertebrae - tailbone) - 4 bones

Lumbar (Supports the overarching weight of the body) - 5 bones

Epiphyseal plates

Growth plates/centers for bone growth

Classification of joints (3 types)

Fibrous (immovable joints eg.skull)

Cartilaginous (slightly moveable joints eg. vertebrae)

Synovial (freely moveable joints)

Cartilage

Connective tissue at end of joints that absorbs impact preventing damage to occur onto bones.

Ligament

Holds two or more bones or cartilage (only bones)

Tendons

Attaches muscle to bones

Synovial Joints

Freely moveable joint + joint capsule

Ball Socket Joint

Allows a wide range of motion

Hinge joint

Allows movement in only one direction

Pivot joint

Where one bone rotates about another

Gliding joint

Only allows gliding or sliding movements

Flexion

Decrease in angle or joint

Extension

Opening up the angle of the joint

Abduction

Movement away from the body

Adduction

Movement of a limb coming back to the midline of the body

Circumduction

Movement of the end of the bone in a circular motion

Supination

Rotation of the hand so that the thumb moves away from the body.

foot rolling outward

Dorsi flexion

Lifting up ankle, closer to leg

Plantar flexion

Pushing toes to the floor, pushing foot away from leg

Voluntary Control

Having conscious control upon the muscle

3 muscle types

Smooth, Cardiac, Skeletal

Smooth Muscle

In hollow organs, and are involuntarily controlled - eg. intestinal walls in stomach

Cardiac muscles

Muscles found in the heart

Skeletal muscle

Muscle that allows the body to move (voluntary) - eg. bicep, quadriceps

Common features of muscles

Nervous control (voluntarily moved)

Excitability

Contractility

Extensibility

Elasticity

Atrophy - muscles decrease in size upon illness or injury

Hypertrophy

Fusiform muscles

Run across tendon, and produce low force

Types of pennate muscles

Unipennate - Fibres only on one side of tendon

Bipennate - Fibres on both sides of the tendon

Multipennate - Fibres branch out from several tendons (most force generated)

Epimysium

Layer of connective tissue

Fasiculus

Bundle of muscle fibres

Endomysium

Connective tissue that binds the muscle fibers together

Sacromere

Smallest unit of muscle contraction

Sliding filament theory

Actin (thin filaments) is pulled by mysoin (thick filament), and causes a contraction in the sacromere.

Muscle Fiber Types

Type 1, Type 2A, Type 2B

Type 1 muscle fibres

Slow twitch fibres

Are for longer duration and aerobic work

Type 2A

Fast twitch fibres

For anaerobic and aerobic parts

Type 2B

Very fast-twitch

For short duration of aerobic work

Motor Unit

One motor neuron and the muscle fibre it stimulates

“All or nothing” principle

If the stimulation is less than threshold, no action is taken, but if stimulation meets the threshold then an action is taken. Intensity is dependent on the frequency of the signal.

Size principle / Henneman principle

Any action irrelevant of intensity starts from small motor units, and then progresses towards larger motor units if required.

Types of muscular contractions

Concentric, Eccentric, Isometric

Concentric contraction

Muscle shortens, causing joint movement to induce in contraction

Eccentric contraction

Muscle opens up, and returns to its original state, becoming on par with gravity.

Isometric Force

Muscle length remains unchanged, but generates force (highest of any contraction)

Agonist

Prime muscle mover

Antagonist

The muscle that relaxes and allows the opposite muscle to engage.

Synergist

Muscle that assists the agonist

e.g. tricep during pushuip

Stabiliser

Group of muscles that stabiles the joint during the exercise.

e.g. rotator cuff, trapezius (shoudler)

Reciprocal Inhibition

When one muscle engages in the movement, while the other relaxes.

Third Class lever

Force is located between axis or resistance of load to be moved.

Main Muscles Of The Body

Coats ends of bones in synovial joints

Hyaline Cartilage

Seperate the vertebrae of the spine

Disc Cartilage

Attach to the sternum via cartilage

Ribs

Hard part of the ear and the tip of the nose

Cartilage

Types of synovial joints

Gliding, ball and socket, hinge, pivot, saddle joint, condyloid joint

Why are third class levers made in the body

To amplify speed

Examples of third class levers

Rackets, hockey stick, cricket bat

Sliding Filament Thoery

In the presence of calcium, the actin attaches to the myosin

The myosin then pulls onto the actin and the ‘H’ zone disappears, because the myosin is stronger than the actin

Then the sarcomere contracts. This causes a translation effect upon all sarcomeres within the muscle, hence causing the muscle to contract.