[003] Muscles And Movement Flashcards
What are the 4 functions of the skeletal system?
- Protection and support for organs
- Allows body movements
- Produces red blood cells
4 stores minerals and fats
What are the 3 functions of the muscular system?
- Maintains posture and balance (ensures that voluntary movements can be carried out without compromising the body’s stability)
- Produces body movement
- Generates body heat
How do we move?
•Muscles contract and pull on bones
• moveable joints between the bones allow movement
• Joints vary in the degree of movement that they allow, some allow little movement
What are the 3 types of joints?
- Fibrous joints - bones linked by fibrous connective tissue permitting little to no movement E.g sutures in cranium
- Cartilaginous joints- bones linked by hyaline cartilage allows limited movement eg pubic symphysis
- Synovial joints - joints enclosed by a fluid filled capsule allows considerable movement
What are the 6 types of synovial joints?
- Plane joint
- Saddle joint
- Hinge joint
- Pivot
- Ball and socket
- Ellipsoid
Give an example of a plane joint and its range of movement.
It allows slight movement in one plane E.g intervertebral
Give an example of a saddle joint and its range of movement.
It permits biaxial movement E.g carpometacarpal pollocks
Give an example of a hinge joint and its range of movement.
Allows for uniaxial movement e.g. elbow
Give an example of a pivot and its range of movement.
It allows rotational movement E.g proximal radioulnar
Give an example of a ball and socket and its range of movement.
It allows multiple axis movement in all axis as well as some rotational movement E.g shoulder
Give an example of an Ellipsoid and its range of movement.
It allows for biaxial movement (but can be uniaxial or multiaxial) E.g atlantooccipital
What are the 9 types of movement?
- Flexion
- Extension
- Abduction
- Adduction
- Lateral rotation
- Medial rotation
- Pronation
- Supination
- Circumduction
What happens when muscles are ‘activated’ by the nervous system?
They contract
What are the 2 types of muscular contractions?
• Isotonic
• Isometric
What is an isotonic muscle contraction?
When the force generated by the muscle is greater than the load so the muscle shortens. Here the load is raised against gravity.
What is an isometric contraction?
When the force generated by the muscle is less than the load so the muscle cannot shorten. Here, the load is not raised against gravity.
What are muscles composed of?
Muscles > fascicle > muscle fibre > myofibrils > thin (actin) and thick (myosin) filaments
How does the sliding filament theory work?
The angle of the myosin head can be changed by ATP hydrolysis to increase the angle between the head and linear body into the cocked state. The myosin head can bind to the actin - tropomyosin complex (thin) and when calcium is present, the energy stored in the cocked head is released. This then causes the myosin head to flick back to its resting state and in turn pulling the thin filament towards the M line.
What is a motor unit?
A motor unit is a motor neuron and the associated muscle fibres that it synapses with/controls.
How is the strength of a muscle contraction increased?
Small motor units are initially activated with large motor units being recruited if needed until all the motor units associated with the muscle are recruited and maximum force is generated
What are length -tension curves?
The maximum tension that a muscle can generate upon contraction depends on an optimal interaction between thin and thick filaments as well as the strength of the input from the motor units.
NB A muscle can generate its maximum tension towards the middle of its sarcomere length range - optimum actin-myosin overlap - and much less when it is too short or too long
What is an agonist and antagonist?
Agonist: muscle that contrasts to produce desired movement.
Antagonist: muscle that contracts to produce a movement in the opposite direction to the one that is desired
What is proprioreception?
Feedback which allows for accurate motor control.
What are the 3 types of movement?
- Reflexive: spinal cord and brainstem
- Rhythmic: arise from central pattern generators (spinal cord and brainstem)
- Voluntary: arise from motor cortex
How does proprioreception work?
• Changes in muscle length - stretch/shortening- detected by muscle spindle
• Changes in muscle tension- defeated by the Golgi tendon organ
• Length and tension information is proprioception
