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(structure of skeletal muscle) Epimysium (2)
-outer most tissue covering the muscle
-forms the over coat of the muscle
*separates the muscle from the neighboring ones
(structure of skeletal muscle) What is the perimysium? (2)
-within the skeletal muscle
-wraps a group of muscle fibers (cells)
(structure of skeletal muscle) What do fasciciles contian?
individual muscle fibers
(structure of skeletal muscle) what is each muscle fiber surrounded by?
connective tissue called endomysium
(structure of skeletal muscle) what are endomysium?
they surround individual muscle cells
What is a neurovascular bundle?
contains the blood vessells and the nerves to a muscle
What do veins remove from the muscles?
waste produced by muscles
can one nerve only be supplied to only one muscke?
no, nerves can supple several muscles
Why is nerve supply important for muscles?
it is important for the actiivty of skeletal muscle as it is dependent on its nerves
Is blood supply importnat to contract muscles?
(muscle attachment) waht are Tendons
extensions of connective tissue sheaths forming a cord-like attachments to a bone
(muscle attachment) where do tendons attach?
to the periosteum
(muscle attachment) Why are tendons attached to rough tubercle on bone?
tendons collect and transmits forces from many different muscle fibers on to a small area of bone.
(muscle attachment) What are aponeurosis
broad sheath of connective tissue to attach muscle
(muscle attachment) how do aponeurosis attach?
broad sheath attaches and forms a ridge or line on the skeletal structure to which it is attached
(muscle attachment) where else can aponeurosis attach? (2)
-deep surface of skin
-dermis of skin
(muscle attachment) what are fleshy attachment? (2)
-msucle fibers continue almost to the bone
-very little connective tissue
(muscle attachment) Why is the attachment site for fleshy attachment smooth?
the forces are widely distributed along the attachment sites ratehr than one particular site
(muscle attachment) what are dermal attahcment?
msucle fibers attach to the connective tissue of the dermis of the skin
(muscle attachment) what do dermal attachments move?
skin rather than skeleton
what does the fascicile arrangment determine?
the shape of muscles
what dictates the strength of a muscle and the direction it pulls?
the orientation of fascicles
shapes of muscles) description of Parallel (2)
-has long strap like muscles with parallel fascicles
- -small cross section
- *weaker muscles
shapes of muscles) description of Pennate arrangement (2)
-their fascicles insert obliquely on a tendon that runs the length of msucle
shapes of muscles) Does pennate arrangement have great cross section?
shapes of muscles) desrcitption of Convergent (2)
-have broad origin and narrow insertion
shapes of muscles) why are convergent muscles strong?
bc all of their fascicles exert their tension on a relatively small insertion site
shapes of muscles) description of circular
-they are sphincter forming rings around the body openings
shapes of muscles) description of fusiform
- thcik in the middle and tapered on both ends forming a belly
- *contractions are moderately strong
relationship between strength, cross section and muscle fibers
the more muscle fibers, the bigger cross section and the stronger the muscle will be
origin and insertion) Origin characterisitics (2)
-usually the less moeveable attachment
origin and insertion) HOw big are the tendons that attach to origin?
they are longer
origin and insertion) charatceritics of insertion (2)
-usually the more freely moveable attachment
origin and insertion) how big are the tendons attached to the insertion?
Muscles must do what to cause an action?
cross a joint
How is the movement determined? (2)
-depending on the axis of the joint crossed
-or side of the joint that the muscle crosses
(ex shoulder joint) Movement in the frontal plane
movement is around an axis going from anterior to posterior
(ex shoulder joint) movement in sagittal plane
movement is around an axis going from medial to lateral
(ex shoulder joint) movement in the transverse plane
movement is around an axis is going from superior to inferior
4 components to lever systems`
What are lever systems?
(components of lever) Lever
elongated rigid object that rotates around a fixed point
(components of lever) fulcrum
fixed point aroud which the levers will rotate (axis)
(components of lever)force/effort
effort applied at one end of the lever to overcome a weight or load
(components of lever) load
the weight or resistance at some point of the leveer that will be overcome by the force
examples of lever system) levers
examples of lever system) axis/fulcrum or pivot points
- *most commonly diarthroses
examples of lever system) forces/effort
examples of lever system) reistance/load
gravity or other external applied resistance
types of lever) description of 1st class lever
fulcrum in the middle of the load and effort
ex) load would be the face, fulcrum would be the pivot point that can rotate the face up and down, and effort is the muscles that pull back the face
types of lever) description of 2nd class lever
load in the middle of fulcrum and effort
ex) wheelbarrow: fulcrum is the wheel, load is on the wagon, and effort is where we pull up and move it
types of lever) description of 3rd class lever
effort/force in the middle of load and fulcrum
ex)lifting weights: load is the weight or external resistance, effort is the point of attachment of the muscle being worked out, and the fulcrum is the joint that is near the msucles that is being worked out.
which is the most commn type of lever in the human body?
3rd class lever
What are 3rd class levers designed to do? (3)
- ROM of the distal end of the lever
- -helps us move through space
- *fulfills our goal of human motion
(fucntional group of muscles) Prime mover or agonist
most effective in causing the movement
- ex) arm flexion= pecs
- arm extension= lats
(fucntional group of muscles) Antagonist
- -opposite of the agonist
- *reverses the movement of agonist
ex) lats to pecs or triceps to biceps
(fucntional group of muscles) synergist (2)
-helps prime mover (agonist) by adding force to the same movement
- -reduces undesirable movement that may occur
- *synergists helps agonist to exert all of their force in one direction
(fucntional group of muscles) fixators or stabilizers (2)
-steadies or supports a bone or body part so that an active muscle has a firm base on whcih to pull one
what else are the fixators/stabilizers involved in?
What is neuromuscular control?
control of the somatic motor system by the nervous system
What does the primary motor cortex in frontal lobe do?
directs all intentional/volitional movements
where does the primary motor cortex send its messages through?
what are alpha motor neurons?
-motor neurons that send messages through spinal nerves of cranial nerves
where are alpha motor neurons located?
-cranial nerve nuclei
what is a motor unit?
is an alpha motor neuron and all the msucle fibers it innervates
where do cranial nerves project to?
muscles of head and neck
where do spinal nerves project to?
muslces of the body
what is neuromuscular junction?
point in where the nerve ending meets the muscle fiber
what is motor end plate?
- folded part of the msucle cell membrane]
- *neuromuscular junction
what is proprioception?
- sensory feedback to the brain from the muscles
- *the sense of knowing where our body is in space
what two structures help us with proprioception?
2 structures for propriception) muscle spindles (2)
-stretch receptors within msucles
- -they tell brain the state of tension of the contraction of a muscle
- *abundant in msucles with fine control
2 structures for propriception) Golgi tendon (2)
-located in tendon of muscles
-they monitor the pull or contraction on a tendon and send info to the brain
what is afferent information? (2)
-messages coming in
what is efferent information? (2)
-messages going out