Muscular System Flashcards
What are the 3 types of muscle cells? Which are voluntary or involuntary? Which are striated?
Smooth Muscle: Involuntary
Cardiac Muscle: Involuntary, Striated
Skeletal Muscle: Voluntary, Striated
What are the 6 functions of the muscular system?
Produce movement
Provide static support, maintain posture
Give form to the body
Provide heat, maintain body temperature
Guard entrances and exits
Communication
How does the muscular system provide static support and maintain posture?
Resist pull of gravity
Maintain tendon tension
Prevent unwanted movements
How does the muscular system give form to the body?
Supports soft tissue
Protects visceral organs (abdominal wall muscles)
How does the muscular system maintain body temperature?
Hold up to 85% of body heat
Shivering
How does the muscular system guard entrances and exits? What are some examples?
Eyelids, pupils, mouth
Intestinal sphincters: valve-like structures formed by muscles, control movement of substances in and out of passages.
How does the muscular system aid in communication?
Facial expression
Body language
Writing
Speech
What are the 2 divisions of the muscular system?
Axial and appendicular
Describe the axial muscular division and its functions.
60% of skeletal muscles
Position head and spinal column
Move rib cage and torso
Describe the appendicular muscular division and its functions.
40% skeletal muscles
Position and support pectoral girdle and pelvic girdle
Support and move upper and lower limbs
Where is the bicep brachii located and what is its function?
Crosses both the shoulder and elbow joints
Main function is at the elbow where it flexes the forearm and supinates the forearm
Describe the parts of a skeletal muscle (origin, belly, insertion).
Origin: bony attachment at stationary end of muscle
Belly: middle region between origin and insertion, produced contraction
Insertion: bony attachment at mobile end of muscle, distal to origin, moves toward origin
What are Fascicles in the anatomy of a muscle?
Bundles of muscle fibers
All fibers are parallel
Fibers run parallel to long axis of muscle
What are the parallel muscles and their examples?
Parallel muscle: biceps brachii muscle
Parallel muscle with tendinous bands: rectus abdominal muscle
Wrapping muscles: supinator
Describe convergent muscles and give an example.
Broad area converges to attachment site
Ex: Pectoralis muscles
Describe unipennate muscles and give an example.
Fascicles form an angle with the tendon.
Fibers on one side of tendon
Ex: extensor digitorum muscle
Describe bipennate muscles and give an example.
Fibers on both sides of tendon
Ex: Rectus femoris muscle
Describe multipennate muscle and give an example.
Tendon branches within muscle
Ex: deltoid muscle
Describe a circular muscle and give an example.
Sphincters guarding entrances.
Insert into themselves
Ex: orbicularis oris muscle
What are the 8 skeletal muscles name indicators?
Location
Origin and Insertion
Direction of fibers
Shape
Number of tendons
Relative size
Relative position
Action
How is location used to indicate skeletal muscle name?
Nearby structure
Ex: Temporalis muscle is near temporal bone
How is origin and insertion used to indicate skeletal muscle name?
First part of name: origin or insertion
Second part of name: insertion or origin
Ex: Sternocleidomastoid (SCM)
Clavicular head & Sternal head= origins
Mastoid process= insertion
How is direction of fibers used to indicate skeletal muscle name?
Rectus: parallel to midline (rectus abdominus)
Transverse: at right angle to midline (transverse abdominis)
Oblique: diagonal to midline (external oblique)
How is shape used to name skeletal muscles?
Deltoid= triangular
Trapezius= trapezoid
Rhomboid= rhombus
Teres= round or cylindrical
What is the function of the deltoid?
prime mover of arm abduction along the frontal plane
What muscles are involved in positioning and moving the scapula (shoulder shrug)?
Trapezius
Rhomboid minor
Rhomboid major
How is shape used to name skeletal muscles?
Latissimus= wide
Serratus= saw-toothed
How is number of tendons used to name skeletal muscles?
Biceps= 2 heads (biceps brachii)
Triceps= 3 heads (triceps brachii)
Quadriceps= 4 heads (quadriceps femoris)
How is relative size used to name skeletal muscles?
Maximus
Major
Magnus
Medius
Minor
Minimus
(Largest to smallest)
How is relative size used to mane skeletal muscles?
Longissimus
Longus
Teres
Brevis
Tertius
(Longest to shortest)
How is relative position used to name skeletal muscles?
External (externus, superficialis)- closer to body surface
Internal (internus, profundus)- deeper muscles
How is relative position used to name skeletal muscles?
Intrinsic- muscles inside an organ
Extrinsic- muscles outside an organ
What are the 8 action terms used to name skeletal muscles?
Flexor- decrease joint angle
Extensor- increase joint angle
Abductor- away midline
Adductor- toward midline
Levator- upward
Depressor- downward
Supinator- palm upward
Pronator- palm downward
Describe the movement of skeletal contraction? Can muscles push?
Shortening of a muscle pulls on bone.
Skeletal muscles can only contract/ pull and relax, they never push.
What happens to insertion to origin points during contraction?
Insertion moves toward origin.
Origin and insertion may reverse.
Skeletal muscles cross at least one joint (muscle bulk lies proximal to the joint crossed).
Angle between bone changes.
What portions of the muscle transfers force to bone?
Tendon
Fascia: sheet of connective tissue under skin that stabilizes, separates, and protect muscles from other internal organs, reduces friction.
Aponeurosis (deep fascia): for muscles needing a wide area of attachment
Describe the role of bones, joints, muscles, and load in movement?
Bones act as lever arms
Joints act as fulcrums (F) or pivots
Muscles provide effort (E) or applied force to move loads
Load (L) or resistance is the weights of body parts, or forces needed to lift, push or pull things outside our bodies.
Describe a first class lever and an example.
Fulcrum between Effort & Load
Head nodding down
Describe a second class lever and give an example.
Load between Effort and Fulcrum
Small force moves a large weight (wheelbarrow)
Calf raises
Describe a third class lever and give an example.
Effort between Load and Fulcrum
Large effort moves smaller loads (tweezers)
Bicep curls
Describe the agonist and antagonist functional groups of muscles and their functions.
Agonist (prime mover): produces a movement
Antagonist: opposes the prime mover
Agonist contracts, antagonist relaxes to maximize efficiency
Ex: bicep contracts while triceps relaxes, flexors vs extensors, abductors vs adductors
Describe the functional groups of synergist and fixator.
Synergist aids prime mover, similar to agonist, prevents unwanted movements.
Fixator stabilizes origin of prime mover to move other end.
What is the brachioradialis and its function?
Superficial muscle on lateral side of forearm
Proximal
Inserts distally on radius
Flexes forearm at elbow
Capable of pronation and supination
How do the 4 functional groups function during elbow flexion?
Agonist: biceps brachii
Antagonist: triceps brachii
Synergist: Brachioradialis, stabilizes elbow joint
Fixator: Trapezius, rhombiods, holds scapula in place
What is reflexive contraction?
Automatic skeletal muscle activities
NOT voluntarily controlled
Ex: Respiratory movements of diaphragm, Knee-jerk reflex
What is Tonic contraction?
Conscious “relaxed” skeletal muscles are slighted contracted (muscle tone)
Does not produce movement
Assists joint stability, maintain posture
Ex: sitting and standing
What is phasic contraction?
Active muscle contractions
What are the 3 types of phasic muscle contractions?
Concentric (shortening: Force > Load
Eccentric (lengthening): Force < Load
Isometric (no movement): Force = Load
Where are axial muscles located?
Head and neck
Vertebral column
Abdominal wall
Back
What are the 6 head and neck muscle groups?
Facial expression
Eye movement
Mastication
Tongue
Pharynx
Anterior neck
What is the function and innervation of the muscles of mastication?
Move the mandible (jaw)
Innervated by trigeminal nerve motor root CN V3
Describe the function and innervation of the muscles of facial expression.
Skeletal muscles that insert into skin and not bone
Some do not originate from bone
Sphincters of facial orifices
Innervated by CN 7
Muscles of facial expression: Depressor anguli oris
Frown
Muscles of facial expression: orbicularis oculi
Blink/ close eyes
Muscles of facial expression: zygomaticus major
Smile
Muscles of facial expression: orbicularis oris
Close mouth/ kiss
Muscles of facial expression: frontalis
Wrinkle forehead, raise eyebrows
Muscles of facial expression: platysma
Tense skin of neck
What are the functions of the pharyngeal muscles?
Lift the soft palate
Elevate the larynx
Deliver food bolus down to esophagus
How are you tongue muscles differentiated?
Names end in glossus
What are the functions of the appendicular muscles?
Position and stabilize pectoral and pelvic girdles.
Move upper and lower limbs
Describe the anatomy and function of the shoulder joint.
Rotator cuff muscles hold humerus in glenoid fossa, stabilizes the joint.
SITS: Supraspinatus, Infraspinatus, Teres minor, Subscapularis
