Lecture 8: Skeletal Muscles Flashcards
What are the three types of muscle tissue? Briefly explain similarities and differences
- Skeletal Muscle: movement of bones, striated, voluntary\
- Cardiac Muscle: located in the heart only, striated (branching), involuntary
- Smooth Muscle: outside walls of viscera, no striations, involuntary
Elaborate the process on how we move:
Skeletal muscle attaches to bones via tendons and pulls bone along the joint to produce movement.
In the appendicular skeleton what are the attachment points called:
Origin: Attached to the stationary bone
Insertion: Attached to the moveable bone
In the axial skeleton what are the attachment locations called.
Superior attachment: moveable bone
Inferior attachment: less mobile bone
What are the functions of skeletal muscles:
→ Movement
→ Maintain posture
→ Protection
→ Regulation of waste products
→ Heat Production
What is the classification tree for a typical skeletal muscle:
- Myofilaments: actin and myosin
- myofibers: Muscle cells
- Fascicles: Bundles of myofibers
- Skeletal muscle: Group of fascicles.
Identify the connective tissue which surround the myofibers, fascicles, and fascicle bundles respectively.
Endomysium: CT around myofiber
Perimysium: CT around fascicle
Epimysium: CT around fascicle bundles
What are the 2 types of contraction: Name a scenario when this can occur:
Isometric Contraction: Tension = no change in muscle length (holding a baby)
Isotonic Contraction: Tension = change in muscle length (moving a baby up)
→ Concentric- muscle length decreases
→ Eccentric- muscle length increases
What are the three components of the lever system:
Fulcrum: fixed point which lever moves
Load: the force imbalance provided by either some weight or bone to oppose movement
Effort: Force provided by muscle which causes movement
What are the types of levers? Give examples.
First-Class Lever: L-F-E , either advantageous or disadvantageous (head movement)
Second-Class Lever : E-L-F, always advantageous (plantarflexion movement)
Third Class Lever F-E-L, Always disadvantageous (Lifting something with hand)
What are the classification of skeletal muscles?
- Parallel
- Fusiform
- Circular
- Triangular
What are the groupings for muscle coordination: Name one example
Agonist: Prime mover (contraction = movement) triceps brachii
Antagonist: Contraction opposes that of the agonist and allows for smoother movement : biceps brachii
Synergist: assist by contributing tension and stabilizing point of origin
Describe the pennate and classify:
Short fascicles which branch of the main tendon of the skeletal muscle:
Unipennate: Arranged in only one side of the tendon
Bipennate: Arranged on 2 sides of the tendon
Multipennate: Attached to tendon from many different directions
What is the innervation and function of the facial muscles.
Innvervated by the FACIAL NERVE
Function: Moves the skin (not bone) to produce facial expression
COMMON: Orbicularis Oris (mouth),,, Orbicularis oculi (eye),,, Nasalis
What is the innervation and function of the muscles of mastification
- Innervated by the TRIGEMINAL NERVE
- Function: Allow to chew (mastificate)
Identify the muscles and what they are used for
(superior → inferior)
Temporalis
Masseter
Used for mastification
Identify the muscles and what they are used for
(superior → Inferior)
Temporalis
Lateral pterygoid
Medial pterygoid
USED FOR MASTIFICATION
What is the innervation for the muscles of the abdomen and what are their function:
Innervated by thoracic spinal nerve
Function: Flexion of the trunk and support of viscera
Identify the important muscles and what they are used for:
RHS: top to bottom
Rectus Abdominis
Transverse abdominis
Internal Oblique
External Oblique
What is the innervation for the muscles of respiration and what is their function
Main Muscle is the Diaphragm which is innervated by the phrenic nerve.
Function: respiration by the flattening of its surface to increase thoracic cavity for respiration
Identify the important muscles and what they are used for:
External Intercostals and Internal Intercostals:
Used in the muscles of respiration
What is the innervation of the muscles of the back, and what are their function?
Innervated by cervical, thoracic, spinal nerves,
Function: Erects the spine
Identify the 3 main muscles and what they function to do.
- Erector Spinae (left to right as seen posteriorly)
→Iliocostalis group
→longissimus group
→spinalis group
Identify the main muscles of the pectoral girdle + thorax
LHS:
Deltoid
Pectoralis Major
Bicep brachii long head
bicep brachii short head
RHS:
Pectoralis Minor (deep)
Identify the main muscles of the pectoral girdle + thorax
RHS:
Trapezius
Latissimus Dorsii
LHS:
Rhomboid Minor
Rhomboid Major
What is the innervation and function of the upper limb (anterior compartment)
innervated by the musculocutaneous nerve
Function: Flexion of the arm
Identify the important muscles and what they are used for
bicep brachii (long head)
bicep brachii (short head)
tricep brachii
Identify the main muscles of the rotator cuff muscles:
Anterior view: Supraspinatus… subscapularis
Posterior View: Infraspinatus… Teres Minor
What is the innervation of the Upper limb (posterior of arm) and function.
Innervated by the Radial Nerve.
Function: Extension of the arm
Identify the important muscles and their function:
Top to Bottom:
Triceps Brachii → Long Head
→ Medial Head
→ Lateral Head
What is the innervation and function of the upper limb (anterior compartment of forearm)
Innervated by the Median + Ulna Nerve
Function: Flexion of the wrist and fingers.
Identify the Important muscles and their function:
Top to Bottom
Pronator Terres
Flexor Carpi Radialis
Palmaris Longus
Flexor Carpi Ulnaris
Identify the main muscle in charge of the flexion of the fingers
Flexor Digitorium Superficialis
What is the innervation of the posterior compartment of the forearm and what is its function
Innervated by the Radial Nerve
Function: Extension of the wrist and fingers
What is the antagonist muscle which controls the extension of the fingers
Extensor digitiorum
What is the innervation of the hand and its function?
Innervated by the median + Ulnar nerve
Function: Fine movements of the finger
What are the main muscles and what are their function?
RHS: Hypothenar Eminence
→ Flexor Digitorum minima brevis
→ Abuctor Digitorum minima
LHS: Thenar Eminence
→ Flexor pollicis brevis
→ Abductor pollicis brevis
What is the function of the gluteal region, name all important muscles.
Function: extension of hip, thigh and external rotation
TOP TO BOTTOM
Gluteus Medius
Gluteus Maximus
What is the innervation of the lower limb (anterior compartment of thigh) and its function:
Innervated by the Femoral Nerve
Function: extensions of the knee
Identify the main muscles and label the function.
Left → Right
Vastus Lateralis
Rectus Femoris
Vastus Medialus
POSTERIOR: Vastus intermedius
What is the innervation of the medial compartment of the thigh? Identify the function of these muscles.
Innervated by the obturator nerve:
Function: Adduction of the hip
Identify the main muscles and label its function:
TOP TO BOTTOM
Adductor longus
Adductor magnus
Adduction of the hip
What is the innervation of the lower limb (posterior compartment of the thigh)
Innervated by the Sciatic Nerve
Function: Extend the Hip and flexion of the knee
Identify the main muscles and their function
Hamstring group: LEFT → RIGHT
- semimembranous
- semitendinous
- bicep femoris long head
- bicep femoris short head
What is the innervation of the lower limb (anterior compartment of the leg). Identify the function:
Innervated by the deep fibular nerve
Function: Allows dorsiflexion
Identify all the main muscles, and label its function.
Left → Right
Extensor digitorum longus
Extensor hallucis longus
Tibialis anterior
What is the innervation of the lower limb (lateral compartment of the leg), identify the function.
innervated by the superficial fibular nerve
function: Eversion of the foot
Identify the main muscles and label its function:
Left → Right
- Fibularis Longus
- Fibularis Brevis
what is the innervation of the lower limb (posterior compartment of the leg)
Innervated by the tibial nerve
Function: Plantarflexion
