PE Unit 1 AOS 1 SAC

Anterior

The front of the body

Posterior

The back of the body

Superior

A body part that is higher than the other (closer to the head)

Inferior

A body part lower than the other (further away from the head)

Medial

Closer to the midline of the body

Lateral

Further away from the midline of the body

Proximal

A body part closer to the trunk of the body

Distal

A body part away from the trunk of the body

Superficial

Closer to the surface of the body

Palmer

The anterior of the hand

Dorsi flexion

top of the foot

Planter

Bottom of Foot

Ligaments

Coonective tissues that connect bone to bone

Cartilage

Flexible connective tissue that supports and protects bones by covering its surface so that they can move against each other.

Joints

Where two or more bones meet

Function of the skeleton

The primary function of the skeleton is to allow movement through a series of anatomical levers which allow muscles to pull on bones to change their position.

Long Bones

Long and thin, eg. humerus, radius, ulna, and femur

Short Bones

Small, cubed shaped eg. carpals and tarsals

Flat Bones

Flattened, broad surface, eg. ribs, scapula, sternum and skull

Irregular Bones

Vary in shape, complex shape, eg. vertebrae, facial bones

Axial Skeleton

Portion of the skeletal system that consists of the skull, rib cage, and vertebral column

Appendicular Skeleton

Bones of the limbs and limb girdles that are attached to the axial skeleton

Cervical Vertbrae

The 7 cervical vertebrae are small, designed to support the next and head.

Thoracic Vertebrae

The 12 Thoracic Vertebrae are larger and provide the anchor point for the ribs to attach and form the rib cage whuch protects the heart and lungs

Lumbar Vertebrae

The 5 lumbar vertbrae are larger and allow the greatest range of movement

Sacral Vertebrae

5 vertebrae which are fused to form the sacrum in the pelvis

Coccyx Vertebrae

4 vertebrae that make up the tail bone

Fibrous (Fixed Joints)

Immovable joint, eg skull, pelvis

Cartilaginous joints

Allow only slight movement, eg. ribs attaching to sternum, lumbar vertebrae

Synovial Joints

Freely movable joints, eg. hip and knee joints, cervical and thoracic vertebrae

Types of synovial joints

pivot, hinge, saddle, plane, condyloid, ball-and-socket

What is a pivot joint?

A pivot joint only rotates one bone around another, eg. atlas and axis (top vertbrae)

Movement type (Pivot)

Rotation

What is a gliding joint?

A gliding joint allows one bone to slide on top of another, eg. carpals/tarsals

Movement type (Gliding)

Glide

What is a ball and socket joint?

Allows a wide range of movements in all directions, eg. shoudler, hip

Movement type (Ball and Socket)

Flextion, extension, adduction, abduction, rotation, circumduction

What is a hinge joint?

Movement in one plane only, eg. knee, elbow

Movement type (hinge)

Flexion, Extension

What is saddle joint?

Movement occurs in two planes, eg. carpo metacarpal joint of thumb

Movement type (saddle joint)

Flexion, Extension, Adduction, Abduction, Circumduction

What is a condyloid joint?

Movement limited to a hinge motion in 2 planes, eg. wrist

Movement type (condyloid)

Flexion, extension, adduction, abduction, circumduction

Abduction

Movement away from the midline of the body

Adduction

Movement toward the midline of the body

Circumduction

Movement is circular and results in the limb forming a cone shape from a joint. For example, pitching the ball in softball.

Extension

A movement that increases the angle between two body parts.

Flexion

Involves movement that results in a decrease in the angle of the joint

Rotation

When a body part makes a turning movement while the rest of the body remains still like turning your head or twisting your spine while your hips remain stationary

Pronation

Movement of the forearm that turns the palm towards the body, so the palm is posterior facing and the ulna and radius are crossed

Supination

Movement results in the forarm rotating so the point in anterior facing and the radius and ulna are uncrossed and parallel to each other

Inversion

Movement where the sole of the foot is angles towards the midline of the body

Eversion

Movement where the sole of the foot is turned away from the midline of the body

Dorsiflexion

Occurs at the ankle joint where the front of the foot is lifted towrds the shin

Plantar Flexion

Occurs at the ankle joint where the heel is lifted from the ground and/or when the toes are painted downwards.

3 types of muscles

skeletal, smooth, cardiac

Skeletal Muscle

Voluntary muscle tissue that is attached to the skeleton by tendons. These muscles contract to pull on bones, allowing for conscious movement.

Functions of the Muscular System

movement, posture, joint stability, heat production

Origin

The origin is at the end where the muscle attaches to the fixed or stationary bone

Insertion

The insertion is the end where the muscle attaches to the bone that is moving the most

Muscle Fibre Arrangement

The arangement of the bundles of musclr fibres is closely related to the force that can be generated in the muscle and the muscle range of motion

Fusiform Muscle Arrangement

The muscle fibres run the length of the muscle in the same direction as the tendon, which can contract rapidly but produce low forces eg. biceps brachii

- because force depends on the number of muscle fibres that can pull on the one tendon at the same time

Pennate Muscle Arrangement

Muscle run at the angles of the tendons. A larger amount of muscle fibres in this arrangement allows pennate muscles to generate greater force.

3 types of pennate arrangment

Unipennate, Bipennate, Multipennate

Unipennate Muscle Arrangement

Muscles fibres that align obliquely on only one side of a central tendon, resembling half of a feather eg. extensor digitorum longus

Bipennate

Muscle fibres attach on both sides of the central tendon, resembling a symmetrical feather eg. rectus femoris (quad)

Multipennate Muscle Arrangement

Multiple rows of muscle fibres arranged obliquely, inserting diagnolly onto several branching tendons that converge into a single main tendon, eg. deltoid

What is a long fibre equal to?

Higher speed and movement eg. fusiform muscles as they run the length of the muscle allowing a greater range of motion

What do short/many fibres equal to?

Higher force, eg., pennate muscles, which contain shorter fibres allowing strong powerful contractions

Slow Twitch Muscle Fibres

Muscle fibres that have a high oxidative capacity and contract slowly.

Charcteristics of slow twitch fibres

• red

• small diameter

• slow reaction time

• lower intensity contractions

• low fstiguability rate

• work at a low intensity

Fast Twitch Muscle Fibres

Muscle fibres that are specialised for high-intensity, explosive anaerobic movements

Characteristics of fast twitch fibres

• white

• high intensity strength activities

• large diamtete

• fast reaction time

• high fatiguabilitiy

• low capilary density

• higher intensity contractions

Sports Examples of Type I (slow-twitch / slow oxidative)

Marathon running, long-distance cycling, distance swimming, triathlon

Sports Examples of Type IIx (fast glycolytic / fast-twitch)

100 m sprint, powerlifting, gymnastics, explosive throwing events (shot put, javelin), vertical jumping

What is the role of the epimysium?

A connective tissue layer surrounding the entire muscle, providing protection and support.

What is the role of the perimysium?

Connective tissue surrounding a bundle of muscle fibres (fascicle) and allows blood vessels and nerves to pass through.

What is the role of the endomysium?

A connective tissue layer surrounding individual muscle fibres, supporting and protecting them.

What are myofibrils?

Long protein structures inside muscle fibres that contain the contractile proteins actin and myosin.

What is the sarcolema?

The sarcolemma is the specialised plasma membrane that surrounds a muscle fibre

Step 1 of Sliding Filament Theory

Electrical impulse arrives at the relaxed muscle via the CNS

Step 2 of Sliding Filament Theory

Calcium is released which bonds the cross bridges to the actin

Step 3 of sliding filament theory

Cross bridges begin to pull the actin filaments towards the middle

Step 4 of Sliding Filament Theory

Muscle Contracts and Shortens

What happens to the sarcomere during contraction?

The sarcomere shortens as the Z-lines move closer together.

What happens to the H-zone?

It gets shorter

What happens to the A-band?

It stays the same length because it represents the length of the myosin filaments.

What happens to actin and myosin during the sliding filament theory?

Actin and myosin do not shorten. Their interaction causes the sarcomere to shorten.

The All or Nothing Principle

The All or Nothing Principle states that if the message/impulse from the brain to the motor unit meets a certain threshold, all muscle fibres in that motor unit will contract maximally at the same time. The number of motor units that are stimulated will determine the force generated.

What happens if the message/impulse does not meet the threshold?

If the message/impulse does not meet the threshold or is too weak, none of the muscle fibres in that motor unit will contract.

What is a smaller force equal to?

Fewer, smaller units are activated

What is a larger force equal to?

More, larger motor units are activated

The Size Principle

Motor units are recruited from smallest to largest as force requirements increase, allowing progressively greater force to be produced. For example, smaller motor units are required for a short handball then a 50 m kick to goal.

Reciprocal Inhibition

Occurs when muscles work in pairs or groups to produce movement.

How does reciprocal inhibition work?

While one muscle contracts (the agonist), the other (the antagonist) relaxes to allow movement.

Agonist

Contracts and shortens

Antagonist

Relaxes and lengthens

Isometric Contractions

Muscle contracts without a change in muscle length eg. planks, side planks, wall sit

Concentric Contractions

Muscle shortens as it pulls bones together, building a force

Push-up: Pushing your body up from the floor.

Squat: Standing back up from the bottom position.

Eccentric contractions

An eccentric contraction occurs when the muscle contracts while lengthening.