Locomotor: Skeletal Muscle & Joints Flashcards
Week 6 Anatomy Supporting Lectures
5 Features
Smooth muscle type features
- Involuntary
- Non-striated
- Mnonucleated
- Iregular fibres
- Reponds to nerve impulses, hormones and local stimuli
5 Features
Cardiac muscle type features
- Involuntary
- Striated
- 1-2 nuclei
- Regular fibres
- Responds to nerve impulses, hormones and local stimuli
5 Features
Skeletal muscle type features
- Voluntary
- Striated
- Multi-nucleated
- Regular fibres
- Responds to nerve impulses only
Five key functional properties of skeletal muscle
- Excitability (responds to nerve stimulus)
- Conductivity (stimulus spreads throughout whole body)
- Contractability
- Elasticity
- Extensibility
Muscle attachment terminology, origin vs insertion
- Origin: Attachment to stationary bone
- Insertion: Attachment to moveable bone
What is a muscle fascicle
Bonus: What sepparates muscle fasicles?
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
What are myofibrils?
Myofibrils are cylindrical contractile units. These are so tightly packed within a fibre that it forces the nuclei to the outside
Tendons vs Ligaments
- Tendon: connects muscle to bone, tough and inelastic
- Ligaments: connect bone to bone, flexible and elastic
What is a muscle fibre?
Bonus: what are fibre surrounded by?
Is a muscle cell or myocyte
Surrounded by the endomysium
What are sarcomeres?
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
Cortical bone features
Also known as ____?
- Rigid
- Tightly packed
- Formed of cylindrical structures called osteons
Also know as compact bone
Trabecular bone features
Also known as ____ or _____ ?
- Consists of loosely arranged struts
Also known as spongy or cancellous
Fibrous vs Cartilaginous vs Synovial joints
- Fibrous is solid and made of fibers (ligaments and sutures)
- Cartilaginous is solid and made of cartilage
- Synovial allows movement
Primary and Secondary cartlaginous joints
- Primary - example growth plates
- Secondary - intervertebral disks
Think in terms of axis of movement and how they fit together
Classifications of synovial joints
- 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)
Example of a plane joint and the movement it allows
Joints connecting the carpal bones
Allows gliding/sliding
Example of a saddle joint and the movement it allows
CMC (carpalmetacarpal) of thumb joint
Allows bi-axial rotation
Example of a hinge joint and the movement it allows
The elbow
Uni-axial rotation
Example of a pivot joint and the movement it allows
Radio-ulnar joint
Uni-axial
Example of an ellipsoid joint and the movement it allows
The wrist
Bi-axial
Example of a ball and socket joint and the movement it allows
Shoulder joint
Multi-axial
Example of a condyloid joint and the movement it allows
Metacarpophalangeal joint
Bi-Axial (doesn’t allow rotation)
Basically the same as an ellipsoid joint
What aren’t all muscles ball and socket joints if they allow the most movement?
Generally there is a tradeoff between movement and stability. Shoulder joints are very mobile however not particularly stable and often dislocate
Hilton’s Law
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.
