Chapter 10: Muscle tissue & organization SYDNEY Flashcards
What are the properties of muscle tissue?
- Excitability
- Conductivity
- Contractility (tension & shorten)
- Elasticity
- Extensibility
What are the different functions of skeletal muscle?
- Movement
- Posture
- Temperature regulation
- Storage/ movement (sphinters)
- Support
Fascicles
Bundles of muscle fibers
what is endomysium?
within muscle; innermost connective tissue layer; fiber
what is perimysium?
surrounds the fascicles; contains extensive arrays of blood vessels & nerves that branch to supply each individual fascicle
what is epimysium?
a layer of dense irregular connective tissue that surrounds the whole skeletal muscle
what is deep fascia?
additional expansive sheet of dense irregular connective tissue that lies external to the epimysium
- separate individual muscles
-binds together muscles w/ similar functions
-forms sheaths to help distribute nerves, blood vessels & fills spaces b/t muscles
which layer is deep fascia internal to?
superficial fascia
what is superficial fascia?
composed of areolar and adipose distinctive tissue that separates muscle from skin
what level is epimysium?
a muscle
what connective tissue covering goes with fascicle?
perimysium
what connective tissue covering goes with muscle?
endomysium
what connective tissue covering goes with fascicle?
Perimysium
what connective tissue covering goes with Fiber?
Endomysium
Muscle fiber
- Located in sarcolemma
- Sarcoplasm
- Contains myofibrils (length of cells & myofilaments)
Myosin
Thick filaments (11nm)
Actin
-Thin filaments (9nm)
- Also tropomyosin & troponin (regulates contraction)
- Nebulin (thin filament formation)
In context of myofilaments, size & density difference between _____________ filaments
thick & thin
Light microscope with myofilaments
-A- bands (appear dark) (thick filaments)
- I bands (appear light) (thin filaments)
Electron microscope related to myofilaments
- H-zone (thick filaments only)
- M-line (attachment site for thick fibers)
- Z-disc (attachment site for thin fibers)
Sarcomere
- The distance between two Z- disc
- The functional unit of skeletal muscle contraction
Neuromuscular junction
- Contains the synaptic knob (synaptic vesicles (contains acetylcholine (ACH))
- Contains synaptic cleft (acetylcholinesterase (breaks down ACH)
- Motor end plate (located in sacrolemma, folded, & has ACH receptors)
Sliding filament theory
-Thick & thin fibers pass each other during contraction
- H-zone & I-band disappear at maximal contraction
- Overall shortening
-Tension
What are the steps involved in skeletal muscle contraction?
- Nerve impulse arrives at the neuromuscular junction
- ACH released into synaptic cleft
- Ach binds to receptors in the motor end plate initiating an impulse along the sarcolemma
- Impulse travels along sacrolemma & T-tubules
- Calcium is released from the sarcoplasmic reticulum
6.Calcium ions bind to troponin
- Troponin moves tropomyosin & exposes active sites on the actin
- Myosin heads bind to active sites & pivots
- ATP binds to myosin head
- Myosin head detaches from actin & resets
11.Nerve impulse stops
- Calcium ions transported back to sarcoplasmic reticulum
- Tropomyosin covers active sites, myosin can’t bind muscles relaxes
Motor units
- “All or none” principle
- Muscle tone
(- resting tension in skeletal muscles - not enough forces for movement
-some motor units always active)
Isometric contraction
Length of muscle doesn’t change (tension greater than or equal to resistance)
Isotonic contraction
Fibers shorten
(- Tension is greater than resistance)
What are the two types of isotonic contractions?
- Concentric contractions
- Eccentric contractions
Concentric contractions
Actively shortens a muscle
Eccentric contractions
Controlled lengthening of a muscle
Slow oxidative fibers
- Relatively thinner
- Slower/ less powerful contractions
- Stay contracted longer
-Aerobic respiration - Dark red (myoglobin)
- Heavily vascularized
-Many mitochondria
Fast Oxidative fibers
-Intermediate fibers
-Fast/powerful contraction
-Aerobic respiration
- Lighter red (less myoglobin)
- Not as vascularized
- Fewer mitochondria
- Medium endurance
What are the different arrangements muscle come in?
-Circular
-Parallel
-Convergent
-Pennate (unipennate, bipennate)
Atrophy
-Wasting
- Tone, size, power
Hypertrophy
-increase in myofibril number
- Increase in myofilaments (fast fibers)
-More mitochondria
-Larger glycogen stores
Tendons
Aponeurosis if thin sheet
-Origin: less mobile attachment, proximal (in limbs)
- Insertion (more mobile, distal (in limbs))
Skeletal muscle action
- Agonist (prime mover)
-Antagonist
-Synergist
Trapezius
-Origin: occipital bone
-Spinous process of C7-T12
-Insertion: Clavicle, scapular spine, acromion
-Action: elevates, retracts, depresses, rotates scapula
-Spinal accessory n.
Latissimus Dorsi
- Thoracolumbar fascia to medial border of intertubercular sulcus of humerus
- Extends, adducts, medially rotates arm
Upper limb: Axioappendicular muscles
•Teres Major
• Rhomboid Major
• Rhomboid Minor
• Levator Scapulae
•Pectoralis major
•Pectoralis minor
•Deltoid
Pectoralis major
- Origin: clavicle.
costal cartilages 2-6, body of sternum - Insertion: Lateral
intertubercular groove - Action
• Arm flexion.
adduction, medial rotation
Pectoralis minor is known as __________ stabilizer
Shoulder
Deltoid
- Origin
• Scapular spine, acromion, acromial end of clavicle - Insertion
• Deltoid tuberosity - Action
• Abducts arm, also flexes & extends arm
Serratus Anterior
Origin
• Ribs 1-8
- Insertion
• Medial border of scapula
- Stabilizes scapula
- “winged scapula” if paralyzed
•Radical mastectomy
• Fencing
Subscapularis
Origin
• Subscapular fossa
- Insertion
• Lesser tubercle of humerus
Action
• Medially rotates humerus
• Stabilizes shoulder
Teres Minor
Origin
• Lateral border of scapula
- Insertion
• Greater tubercle of humerus
Action
• Adducts and laterally rotates arm
• Stabilizes shoulder
Upper limb: Anterior arm muscles
-Biceps Brachii
-Brachialis
Biceps Brachi
Spans shoulder & elbow
- 2 heads
Origin
•Supraglenoid tubercle of scapula
• Coracoid process of scapula
- Insertion
• Radial tuberosity
- Action
• Flexes forearm. arm
• Supinator of forearm
Brachialis
Spans elbow only
- Origin
• Anterior surface of humerus.
- Insertion
• Coronoid process of ulna
- Action
•Flexes forearm
Upper limb: Posterior arm muscles
Triceps brachii
Triceps brachi
Origin
• Infraglenoid tubercle & posterior humerus
- Insertion
• Olecranon of ulna
Action
• Extends forearm, extends & adducts
arm
Upper limb: Forearm Anterior Compartment muscles
- Pronator teres
-Flexor carpi radialis
-Palmaris longus
-Flexor carpi ulnaris
-Flexor digitorum superficialis
Pronator teres
Anterior compartment
- Origin
• Medial epicondyle of humerus & coronoid process of ulna
- Insertion
• Lateral surface of radius
- Action
•Pronates forearm
Flexor Carpi Radialis
Anterior compartment
- Origin
• Medial epicondyle of humerus
- Insertion
• Base of Metacarpal I and II
- Action
• Wrist flexor, abducts hand
Palmaris longus
Anterior compartment
- Origin
• Medial epicondyle of humerus
- Insertion
• Palmar aponeurosis
- Action
• Weak wrist flexor
Flexor Digitorum Superficialis
Anterior Compartment
- Origin
• Medial epicondyle of humerus.
coronoid process of ulna
- Insertion
• Middle phalanges of digits 2-5
- Action
• Flexes wrist metacarpal joints and interphalangeal joints
Upper limb: forearm posterior compartment muscles
-Mostly extensors
-Brachioradialis
-Extensor Carpi radialis longus
-Extensor digitorum
-Extensor digitorum
-Extensor Carpi Ulnaris
Brachioradialis
Lateral side of forearm
- Origin: anterior side of distal humerus
- Insertion: Styloid process of radius
- Action: flexes forearm
Extensor Carpi Radialis
Longus
Posterior compartment
- Origin
• Lateral epicondyle of humerus
- Insertion
• Base of Metacarpal II
Extensor Carpi Ulnaris
Posterior compartment
- Origin
• Lateral epicondyle of humerus
- Insertion
• Base of Metacarpal V
Lower limb: Gluteal region muscle
Gluteus Maximus
Gluteus maximus
Origin
•Iliac crest, sacrum.
соссух
- Insertion
. Tiotibial tract, linea aspera
- Action
• Extends and laterally rotates thigh
Lower Limb: Gluteal Region muscles
- Gluteus medius and minimus
-Hip stabilizers
-Pitiformis
-Obturartor internus
-Quadratus femoris
Gluteus Medius and
Minimus
Origin
• Lateral surface of
- Insertion
• Greater trochanter of femur
Action
• Abducts thigh
Hip Stabilizers
Pull femur into acetabulum
- Origin
• Sacrum and/or pelvis
- Insertion
• Greater trochanter
Lower limb: Anterior thigh
-Sartorius
-Iliopsoas
-Quadriceps femoris
•Rectus femoris
•Vastus laterales
•Vastus intermedius
Sartorius
Origin
• Anterior Superior Iliac
Spine
- Insertion
• Medial side of tibial tuberosity
- Action
• Flexes thigh, knee, rotates leg medially
• “cross-leg sitting”
Iliopsoas
Origins
• Iliacus: iliac fossa
• Psoas major:
transverse processes
of thoracic and
lumbar vertebrae
- Insertion
• Lesser trochanter of
femur
- Actions
• Hip flexor
Quadriceps Femoris has how many muscles
4 muscles
Rectus Femoris
Origin
Anterior inferior iliac
spine
- Insertion
Tibial tuberosity (via
patella)
- Action
• Hip flexor
. Knee extensor
Vastus group
Vastus Lateralis, Intermedius, Medialis Origin
• Linea aspera, anterior femur
- Insertion
• Tibial tuberosity (via
patella)
- Action
• Knee extensor
Lower limb: Posterior thigh muscles
Hamstrings
-Biceps femoris (Long Head)
-Semimembranosus
-Semitendinosus
Hamstrings
Biceps femoris (long head), Semimembranosus, Semitendinosus
- Origin: Ischial tuberosity
- Insertion
• Biceps femoris: proximal fibula
• Others: medial condyle of tibia
- Action: Hip extension, knee flexion
Lower limb: Medial thigh muscles
Adductor compartment
-Pectineus
-Adductor brevis
-Adductor longus
-Adductor magnus
-Gracilis
Adductor compartment
Origin
• Pubis & Ischium
- Insertion
• Linea aspera
• Adductor tubercle
- Action: Adduct thigh
Gracilis
Origin
•Pubis
- Insertion
• Proximal medial
surface of tibia
- Action
• Adducts thigh, flexes hip & knee
Lower limb: Anterior leg muscles
Tibialis Anterior muscle
Tibialis Anterior
Origin
• Lateral condyle, shaft of tibia
- Insertion
• Metatarsal I, adjacent tarsals
Action
• Dorsiflexes, inverts foot
Lower limb: Posterior leg muscles
- Gastrocnemius
-Soleus
Gastrocnemius
Origin
• Distal femur above condyles
- Insertion
•Calcaneus
- Action
Flexes knee
• Plantar flexes foot
Soleus
Origin
• Fibular head. medial tibia
- Insertion
• Calcaneus
- Action
• Plantar flexes foot
Lower limb: lateral leg muscles
-Fibularis longus
-Fibularis brevis
Fibularis longus
Origin: head of fibula, lateral tibia
- Insertion: Base of MT I, distal tarsals
- Action: eversion
Fibularis brevis
Origin: distal fibular shaft
- Insertion: MT V
- Action: eversion