Locomotor: Skeletal Muscle & Joints

Question 1

5 Features

Smooth muscle type features

Answer 1

• Involuntary
• Non-striated
• Mnonucleated
• Iregular fibres
• Reponds to nerve impulses, hormones and local stimuli

Question 2

5 Features

Cardiac muscle type features

Answer 2

• Involuntary
• Striated
• 1-2 nuclei
• Regular fibres
• Responds to nerve impulses, hormones and local stimuli

Question 3

5 Features

Skeletal muscle type features

Answer 3

• Voluntary
• Striated
• Multi-nucleated
• Regular fibres
• Responds to nerve impulses only

Question 4

Five key functional properties of skeletal muscle

Answer 4

• Excitability (responds to nerve stimulus)
• Conductivity (stimulus spreads throughout whole body)
• Contractability
• Elasticity
• Extensibility

Question 5

Muscle attachment terminology, origin vs insertion

Answer 5

• Origin: Attachment to stationary bone
• Insertion: Attachment to moveable bone

Question 6

What is a muscle fascicle

Bonus: What sepparates muscle fasicles?

Answer 6

These are the base packets of fibres within a muscle, how you arrange these and how many of these you include define the muscle

Separated by perimysium

Question 7

What are myofibrils?

Answer 7

Myofibrils are cylindrical contractile units. These are so tightly packed within a fibre that it forces the nuclei to the outside

Question 8

Tendons vs Ligaments

Answer 8

• Tendon: connects muscle to bone, tough and inelastic
• Ligaments: connect bone to bone, flexible and elastic

Question 9

What is a muscle fibre?

Bonus: what are fibre surrounded by?

Answer 9

Is a muscle cell or myocyte

Surrounded by the endomysium

Question 10

What are sarcomeres?

Answer 10

These are repeating protein pattern that make up myofibrils. They are the smallest componant of skeletal muscle

One sarcomere goes from z line to z line

Question 11

Cortical bone features

Also known as ____?

Answer 11

• Rigid
• Tightly packed
• Formed of cylindrical structures called osteons

Also know as compact bone

Question 12

Trabecular bone features

Also known as ____ or _____ ?

Answer 12

• Consists of loosely arranged struts

Also known as spongy or cancellous

Question 13

Fibrous vs Cartilaginous vs Synovial joints

Answer 13

• Fibrous is solid and made of fibers (ligaments and sutures)
• Cartilaginous is solid and made of cartilage
• Synovial allows movement

Question 14

Primary and Secondary cartlaginous joints

Answer 14

• Primary - example growth plates
• Secondary - intervertebral disks

Question 15

Think in terms of axis of movement and how they fit together

Classifications of synovial joints

Answer 15

• Hetero-morphic joints will allow movement about an axis.
• Homo-morphic can allow sliding on a plane (in the case of the carpal joints) or movement about an axis (in the case of a saddle joint)

Question 16

Example of a plane joint and the movement it allows

Answer 16

Joints connecting the carpal bones

Allows gliding/sliding

Question 17

Example of a saddle joint and the movement it allows

Answer 17

CMC (carpalmetacarpal) of thumb joint

Allows bi-axial rotation

Question 18

Example of a hinge joint and the movement it allows

Answer 18

The elbow

Uni-axial rotation

Question 19

Example of a pivot joint and the movement it allows

Answer 19

Radio-ulnar joint

Uni-axial

Question 20

Example of an ellipsoid joint and the movement it allows

Answer 20

The wrist

Bi-axial

Question 21

Example of a ball and socket joint and the movement it allows

Answer 21

Shoulder joint

Multi-axial

Question 22

Example of a condyloid joint and the movement it allows

Answer 22

Metacarpophalangeal joint

Bi-Axial (doesn’t allow rotation)

Basically the same as an ellipsoid joint

Question 23

What aren’t all muscles ball and socket joints if they allow the most movement?

Answer 23

Generally there is a tradeoff between movement and stability. Shoulder joints are very mobile however not particularly stable and often dislocate

Question 24

Hilton’s Law

Answer 24

The nerve that supplies the muscles acting on a joint also supply the joint.

This means that different joints affected by the same muscle e.g. the knee and hip joint are both acted on by the rectus femoris can reffer pain. So someone reporting pain in their knee could actually have a problem witht he hip and you must examine both.