*Anatomy - movement Flashcards
3 different types of muscle?
Voluntary?
Striated?
Cardiac muscle (involuntary and started) Smooth muscle (involuntary and non-striated) Skeletal muscle (voluntary and striated)
What is skeletal muscle made up of?
Skeletal muscle -> fasciles -> muscle fibre (myocyte/ muscle cell) -> myofibrils -> actin and myosin microfilaments
Why does striations look like stripes?
Due to overlapping actin and myosin
What happens when a muscle is strained?
Some of the muscle fibres are torn
Types of skeletal muscles? (5)
Circular Pennate Fusiform Flat with aponeurosis Quadrate
Example of a circular muscle
Orbicularis oculi
Example of a pennate muscle
Deltoid
Example of fusiform muscle
Biceps brachi
Example of a flat muscle
External oblique
Example of a quadrate muscle?
Rectus abdominus
What is a flattened tendon called?
An aponeurosis
What are the 2 points at which muscle attaches to bone called?
Origin(s)
Insertion(s)
(origin is a fixed point where as the insert moves with contraction)
How many origins and insertions does biceps brachi have?
2 origins
1 insertion
Along which axis does a muscle contract?
Long axis
Which joints can biceps brachii move?
Shoulder
Elbow
Radioulnar joint
(as spans all 3 of these joints)
What is a reflex?
A rapid, predictable, involuntary reaction to “danger”
What are the 2 main reflexes involving skeletal muscles?
Stretch reflex (deep tendon reflexes) Flexion withdrawal reflex (sudden flexion to withdraw when we touch something potentially dangerous)
What is an example of a stretch (deep tend reflex)?
Biceps jerk, knee jerk
How are deep tendon (stretch) reflexes tested?
Tendon hammer is used to apply a brief, sudden stretch to the muscle via its tendon
In order to prevent overstitching, the muscle contracts, pulling on the tendon and causing a knee jerk
What tendon is being stretched when creating a knee jerk reflex?
The patellar tendon
How does a deep tendon reflex work in terms of nerves?
Sensory nerve from muscle detected stretch and tells spinal cord
Synapse in spinal cord between sensory and motor nerves
Motor nerve from spinal cord passes message to muscle to contract
What is the synapse called where the motor nerve communicates wit the skeletal muscle during a reflex?
Neuromuscular junction
What is the name of the whole route taken by the action potentials during a reflex?
Reflex arc
What does a normal stretch reflex indicate is working? (5)
The muscle Its sensory nerve fibres Its motor nerve fibres The spinal cord connection between the 2 The neuromuscular junction "descending controls" from the brain
What is the brains role in a reflex?
To prevent the reflex from being overly brisk
What is wrong with a muscle that does not have a functioning motor nerve supply?
It is paralysed
What is paralysed muscle unable to do?
Contract
What will a paralysed muscle look like on examination?
Reduced tone
What is the word used to describe a muscle that has an intact and functioning motor nerve but the descending controls from the brain aren’t working?
Spastic
What will a spastic muscle appear like on examination?
Increased tone
What has happen to atrophic muscle fibres?
Why does this happen?
They have become smaller, reducing the muscle’s bulk
Immobilisation e.g. after fracture. damage to motor nerve supply
What is the opposite of atrophy?
hypertrophy
What happens during muscle hypertrophy?
The skeletal muscles enlarge
What are the layers present above skeletal muscles?
Deep fascia (fibrous tissue -glistening white layer)
Superficial fascia (adipose tissue)
Dermis (collagen/ elastic fibres)
Epidermis (epithelium)
What is the inter muscular septum?
An extension of the deep fascia that splits the muscles of the limbs into different compartments
what are the muscle compartments of the thigh? (3)
Anterior
Medial
Posterior
What are the muscle compartments of the thigh? (2)
Anterior
Posterior
Lateral
What are the muscle compartments of the arm? (2)
Anterior
Posterior
What are the muscle compartments of the forearm? (2)
Anterior
Posterior
Why are muscular compartments important?
They prevent infection from spreading into other compartments
What is it called when increased pressure caused by tissue swelling or an increase in fluid affects functions of the muscles or nerves in the compartment?
Compartment syndrome
What can be performed to relieve pressure in compartment syndrome?
A fasciotomy
