muscles Flashcards
how are muscles named?
- direction
- location
- size
- shape
- branches
- attachments
how many joints do the brachioradialis, triceps and the biceps branchi pass through?
which bones do they attach to?
biceps branchi-2- ulna, radius, scapula
branchioradialis-1 humerus, radius
triceps- 2
different types of muscles based on actions?
1- Flexors- when they contract they bring the two bones closer together e.g. the anterior muscles of the arm and forearm
2- Extendors- when they contract they bring the two bones further apart e.g. the the posterior muscles of the arm and the forearm.
3- Synergists: muscles- which are not agonists- which perform the same action as the agonist on the joint.e.g. branchialis and branchioradialis
4- Rotator cuff muscles: help stabilise the joint e.g. supraspinatatous, infraspinatous muscles
innervation of muscles?
Limb/ Appendicular muscles are innervated by groups of nerves from the same network-Plexus.
The upper limbs are innervated by the Cervical C5-T1 branchial plexus nerves
The lower limbs are innervated by the Sacro-lumbar plexus l1-s4
sphincter muscles:
- how are they arranged
- how do they work
- what type of muscle are they
They are made up of circular shaped fibres which thicken around the structure.
When they contract they close the tube of the structure.
They are usually smooth muscle but are skeletal when controlling the exit of bodily fluids.
When there are both types of muscle present, the smooth muscle is deeper.
differences between skeletal, cardiac and smooth?
Skeletal- multinucleate, striated, diagonal striations
Cardiac-mononucleate, intercalated discs, horizontal striations
Smooth- mononuclear-flat nuclei, no striations
How are muscles comparmentalised?
1- Based on nerve innervation
2-Based on similar action on joints
3-Separated by a deep inter muscular septa
What is the function on intercalated discs in the cardiac muscle?
It contains gap junctions which allow pacemaker cells to contract simultaneously
