Anatomy: Muscles and nerves Flashcards
Pre-practical
In basic words, describe what flexion is.
Bend/shorten a joint by pulling bones closer together
What is extension?
Unbend/lengthen a joint by pulling bones further apart
Give an example of a muscle that causes flexion when it contracts.
Biceps brachii
Give an example of a muscle that causes extension when it contracts.
Triceps brachii
In anatomical terms, describe the position of the biceps brachii.
Anterior
“All skeletal muscles cross at least ___ joint”
One
“The bulk of a skeletal muscle lies _____ to the joint crossed”
Proximal
All skeletal muscles have at least 2 attachments.
What are their names?
Origin and insertion
True or false
Most skeletal muscles pull, but a few exceptions push.
False
Skeletal muscles can only pull, never push
What happens when a skeletal muscle contracts?
Based on the relative positions of the origin and insertion
Origin and insertion move closer to each other
What is a nerve plexus?
Nerves containing fibres from more than one spinal nerve
What supplies the appendicular (limb) muscles, plexuses or segmental nerves?
Plexuses
EG - brachial plexus supplies the arm
How are nerve plexuses different from nerves that supply segmentally?
Plexuses - mixed fibres from different spinal nerves
Segmental - separate nerves that have not mixed with each other
What is Hilton’s law?
The nerve supplying the muscles, extending across and acting at a joint, also innervates that joint and the overlying skin
Appendicular muscles are arranged in compartments. What are these called, and what separates compartments?
Fascial/muscle compartments
Separated by connective tissue septa
Skeletal muscle: mononucleate or multinucleate?
Multinucleate
“Bundles of muscle fibres are called _____”
Fascicles
What organelle is especially abundant in skeletal muscle?
Mitochondria
Which muscle types have striations?
Skeletal
Cardiac
What are the intercalated discs in cardiac muscle?
Regions where the ends of cells are connected
What feature do intercalated discs have, and why is it important?
Gap junctions
Allows the muscle cells to be electrically coupled ∴ contract in synchrony
What is the difference between a ligament and a tendon?
Tendon = bind muscle to bone
Ligament = bind bone to bone
“Spinal nerves exit the vertebral canal through ______ ______”
Intervertebral foramen
Nerve plexuses are formed from which rami?
Ventral rami
The nerves coming from one region of the spinal cord do not form plexuses. What region is this?
Thoracic
In a spinal nerve, a layer of connective tissue encases individual nerves and their myelin sheath.
What is this called?
Endoneurium
What is contained in a fasciculus?
Bundle of nerves
What encases a fasciculus?
Perineurium
A spinal nerve is made of a bundle of fasciculus. What other structure is present in nerve?
Blood vessels
What is the name of the layer that encases spinal nerves?
Epineurium
What is a synergist?
A muscle that works alongside the agonist to stabilise and assist the movement of a joint
Fixator muscles are common around the hips and shoulder joints. What are they?
Stabilising muscles
These muscles and their tendons allow mobile joints to move freely without risk of dislocation
Other than fixator muscles. what feature is found in and around joints to aid stabilisation?
Ligaments
An aponeurosis is a type of tendon found in the abdominal region. Describe it’s shape.
Flat, thin, broad
What is a dermatome?
An area on the skin that is supplied by nerves from a single nerve root (eg C6)
What is the difference between cutaneous nerves, and a dermatome?
CN = Nerves at the skin D = Area of skin supplied by single nerve type
Ie a dermatome will be supplied by many different cutaneous receptors
What cell produces the myelin that surrounds axons?
Schwann cells
