Chapter 14: Muscular System Flashcards
What is skeletal muscle?
attached to bones
Striated, voluntary, limited capacity to regenerate
What is cardiac muscle?
wall of the heart
Striated, involuntary, with stem cells to regenerate cardiac muscle
What is smooth muscle?
located in viscera: participates in internal processes such as digestion and regulation of blood pressure
Non-striated, involuntary, with good ability to regenerate
What is whole muscle made of?
A whole muscle is made up of many muscle fibers
Where are muscle fibers arranged in?
Muscle fibers are arranged in bundles called fascicles
Where are many fascicles in?
They are inside of whole muscle
What does connective tissue do?
Connective tissue surrounds and protects
What does hypodermis do?
separates muscle tissue from skin
allows a pathway for nerves, blood vessels, lymphatic vessels to enter and exit muscles
What is Fascia and what do they do?
Fascia is dense irregular connective tissue and it surrounds organs of the body and muscles
What does Fascia allow for us?
It allows free movement of the muscle, carries nerves, blood vessels, and lymphatic vessels, and fills spaces between muscles
What are 3 layers of Fascia?
- Epimysium = surrounds entire muscle
- Perimysium = surrounds fascicles
- Endomysium = surrounds individual muscle fibre
Where do 3 layers of Fascia extend?
The three together extend beyond a muscle as a tendon
How do muscles attached to bones?
Muscles are attached to bones by tendons (dense connective tissue)
What does blood supply do for us?
blood supply needed for muscle contraction, plus the following:ATP (adenosine triphosphate), Nutrients, Oxygen
What accompanies each nerve that penetrates a skeletal muscle?
one artery and two veins
What is skeletal muscle tissue composed of?
Muscle Fibers, Myofibrils, Plasma membrane – sarcolemma, Transverse Tubules (T tubules), Sarcoplasmic Reticulum– Ca2+ storage site
What is origin of muscle movement?
Attachment point to bone but do not move during contraction
What is insertion of muscle movement?
Attachment point to bone that is movable
What is agonist (prime mover) of muscle movement?
Produces desired action
What is Antagonist of muscle movement?
Produces an opposite action
What is synergist of muscle movement?
assists the prime mover
What are origin, insertion, and action for muscle Occipital frontalis Frontal belly?
Origin: Epicranial aponeurosis
Insertion: Skin superior to orbit
Action: Raises eyebrows
What are origin, insertion, and action for muscle Occipital frontalis occipital belly?
Origin: Occipital and temporal bone
Insertion: Epicranial aponeurosis
Action: Draws scalp backward
What are origin, insertion, and action for muscle Massester
Origin: Zygomatic arch
Insertion: Mandible
Action: Elevate mandible-chewing
What are origin, insertion, and action for muscle Tempolaris
Origin: Temporal bone
Insertion: Mandible
Action: Elevate and retract mandible-chewing
What are origin, insertion, and action for muscle Sternocleidomastoid
Origin: Manubrium and clavicle
Insertion: Occipital bone and mastoid process
Action: Flexes and rotates head
What are origin, insertion, and action for muscle Pectoralis major?
Origin: Medial clavicle and sternum
Insertion: Humerus
Action: Adducts humerus-push ups and move straight arm to midline & Medial roation of shoulder-Arm wrestling
What are origin, insertion, and action for muscle Pectoralis minor?
Origin: Ribs 3-5
Insertion: Coracoid process of scapula
Action: Elevate ribs-forced inspiration & pull scapula forward and down
What are origin, insertion, and action for muscle Rectus abdominus?
Origin:Pubic symphysis
Insertion: Cartilage of ribs 5-7 & Xiphoid process
Action: Flexes vertebral column aids in-defecation, urination, forced expiration, child-birth
What are origin, insertion, and action for muscle External oblique?
Origin: Ribs 5-12
Insertion: Linea alba
Action: Flexion and rotation of vertebral column
What are origin, insertion, and action for muscle Internal oblique?
Origin: Ilium
Insertion: Cartilage of ribs 9-12
Action: Flexion and rotation of vertebral column
What are origin, insertion, and action for muscle Transverse abdominis
Origin: Ilium lumbar fascia Ribs 6-12
Insertion: Xiphoid process and linea alba pubis
Action: Compresses abdomen stabilize trunk
What are contract muscles for normal inspiration?
Diaphragm, External intercostals
What are relaxation muscles (passive) for normal expiration?
Diaphragm, External intercostals
What are contract muscles for forced inspiration?
Sternocleidomastoid (elevate sternum), Pectoralis minor (elevate ribs)
What are relaxation muscles for forced expiration?
Internal intercostals
Abdominal muscles: Transverse abdominis, Rectus abdominis, Internal oblique, External oblique
What are origin, insertion, and action for muscle internal intercostal?
Origin: Superior border of each rib
Insertion: Inferior border of next rib
Action: depress ribs (expiration)
What are origin, insertion, and action for muscle external intercostal?
Origin: Inferior border of each rib
Insertion: superior border of next rib
Action: elevate ribs (inspiration)
What are origin, insertion, and action for normal inspiration?
Origin: Xiphoid process, cartilage of ribs 6-12 and lumbar vertebrae
Insertion: Central tendon
Action: Contraction causes it to flatten; increase size of thoracic cavity (inspiration)
Relaxation: return to original shpae (expiration)
What are origin, insertion, and action for muscle Supraspinatus?
Origin: Scapula
Insertion: Humerus
Action: Abduction of arm
What are origin, insertion, and action for muscle Infraspinatus?
Origin: Scapula
Insertion: Humerus
Action: Lateral rotation of arm
What are origin, insertion, and action for muscle Teres minor?
Origin: Scapula
Insertion: Humerus
Action: Lateral rotation of arm
What are origin, insertion, and action for muscle Teres major?
Origin: Scapula
Insertion: Humerus
Action: Extension and adduction of arm
What are origin, insertion, and action for muscle Latissimus dorsi
Origin: Spines of vertebrae T7-L5, sacrum, ilium
Insertion: Humerus
Action: Extension and adduction of arm
What are origin, insertion, and action for muscle Deltoid
Origin: Clavicle and scapula (Spine)
Insertion: Humerus (Deltoid tuberosity)
Action:Abduction, flexion, extension, and medial and lateral rotation of arm
What are origin, insertion, and action for muscle subscapularis
Origin: Scapula
Insertion: Humerus
Action: Rotates arm medially at shoulder point
What do rotator cuff muscles (SITS) do?
They stabilize the shoulder joint
What are the muscles for rotator cuff muscles?
Supraspinatus, Infraspinatus, Teres Minor and Subscapularis (anterior)
What is the action for muscle Iliocostalis, Longissimus, and Spinalis?
Maintain erect spinal column and head, Lateral flexion of trunk
Where is Iliocostalis located?
At lateral
Where is Longissimus located?
At intermediate
Where is Spinalis located?
At medial
What are origin, insertion, and action for muscle Biceps brachii?
Origin: Long head-superior coracoid process, short head-inferior coracoid process
Insertion: Radius
Action: Flexion/supination forearm, flexion of arm at shoulder
What are origin, insertion, and action for muscle Brachialis?
Origin:Lower humerus
Insertion:Ulna
Action:Flexion of forearm
What are origin, insertion, and action for muscle Triceps brachii?
Origin: Lateral posterior scapula
Insertion: Ulna
Action: Extension of forearm
What are origin, insertion, and action for muscle Psoas major?
Origin: Lumbar vertebrae
Insertion: Femur
Action: Hip flexion and lateral rotation
What are origin, insertion, and action for muscle Iliacus?
Origin: Ilium
Insertion: Femur
Action: Hip flexion and lateral rotation
What are origin, insertion, and action for muscle Recturs femoris (quadriceps)?
Origin: Anterior iliac spine
Insertion: Tibia (tibial tuberosity, via patellar ligament)
Action: Extends the knee, flexes the hip
What are origin, insertion, and action for muscle Vastus laterlais (quadriceps)?
Origin: Proximal femur
Insertion: Tibia
Action: Extends the knee
What are origin, insertion, and action for muscle Vastus medialis (quadriceps)?
Origin: Proximal femur
Insertion: Tibia
Action: Extends the knee and adducts thigh
What are origin, insertion, and action for muscle Vatus intermedius (quadriceps)?
Origin: Anterior lateral femur
Insertion: Tibia
Action: Extend the knee
What are origin, insertion, and action for muscle sartorius?
Origin:Ilium
Insertion: Tibia
Action: flexes hip & adducts and laterally rotates thigh
What are origin, insertion, and action for muscle Adductor longus?
Origin: Pubis
Insertion: Femur
Action: Adducts and laterally rotates femur
What are origin, insertion, and action for muscle Gluteus maximus?
Origin: Posterior ilium, scrum and coccyx
Insertion: Iliotibial tract and femur
Action: Movements of thigh-Extend, hyperextend, and laterally rotates
What are origin, insertion, and action for muscle Gluteus medius?
Origin: Ilium
Insertion: Femur
Action: Movements of thigh-abduct and medial rotation
What are origin, insertion, and action for muscle Semitendinosus (Hamstring)?
Origin: Ischium
Insertion: Medial tibia
Action: Flexes knee and extend thigh
What are origin, insertion, and action for muscle Biceps femoris (Hamstring, long and short heads)?
Origin: Ischium
Insertion: Lateral tibia
Action: Flexes knee and extend thigh
What are origin, insertion, and action for muscle Seminembranosus (Hamstring)?
Origin: Ischium
Insertion: Medial tibia
Action: Flexes knee and extend thigh
What are origin, insertion, and action for muscle Soleus?
Origin: Proximal tibia fibula
Insertion: Calcaneus (via calcaneal, achilles, tendon)
Action: Planter flexion of foot
What are origin, insertion, and action for muscle Gastronemius?
Origin: Distal femur
Insertion: Calcaneus
Action: Planter flexion of foot, flexion of knee
What are origin, insertion, and action for muscle Tibialis anterior?
Origion: Proximal tibia
Insertion: First metatarsal
Action: Dorsiflexion of foot
What are defining characteristics of skeletal muscle?
It is multinucleated.
It contains many mitochondria.
It has special structures called transverse tubules (T tubules).
It has myofibrils and sarcomeres
What is sarcolemma?
Plasma membrane
What is sarcoplasm?
Cytoplasm
What is sarcoplasmic retiuculum?
Smooth ER
What is myofibrils and what does myofibrils do?
Myofibrils are bundles of contractile filaments and they give skeletal and cardiac muscle characteristic striated appearance
How are myofibrils arranged?
They are orderly arrangements of thick and thin filaments
What does thin filaments have?
Actin plus tropomyosin and troponin proteins
What does thick filaments have?
Myosin
What happens during muscle contraction?
Whole muscle shortens because the individual filaments slide across one another but Thick and thin filaments themselves do not shorten
Does shortening always occur during the contraction?
No, they don’t
What are 3 types of contraction?
Isometric, Concentric and Eccentric contraction
What is isometric?
muscle does not noticeably change length, such as holding a dumbbell at constant position
What is concentric?
Muscle shortens during contraction
What is eccentric?
Muscle gradually lengthens, but under tension,such as lowering yourself during chin up
What does sarcoplasmic reticulum (SR) have?
Sarcoplasmic reticulum has Ca2+ stored and it releases following membrane excitation
How are SR and T-tubules connected?
They are connected with cell membrane proteins
How is calcium removed and what does it require?
Calcium is removed from cytosol to SR by active transport and it requires ATP
What is muscle tone?
Myosin heads always binding and releasing actin which keep muscles somewhat firm even when muscles are relaxed (not 100% relaxed)
What does muscle tone do for us?
It prevents muscles from over stretching and help maintain posture and balance
What causes cramps?
Dehydration, Over-exercise, Calcium/potassium/magnesium imbalance between inside and outside of cell, Old age, Injury and inflammation
What does neuromuscular junction (NMJ) have?
Motor neurons and cell bodies
What are motor neurons?
Nerve cells whose axons innervate skeletal muscle fibres
Where are cell bodies?
Located in brainstem or spinal cord
What do axon terminals of motor neuron have?
Vesicles that contain the neurotransmitter acetylcholine (ACh)
What is motor end plate?
Region of muscle fibre plasma membrane directly under axon terminal
What is neuromuscular junction(NMJ)?
The junction of an axon terminal with the motor end plate
Where does ACh bind to?
Ligand-gated receptors that are on motor end plate and open ion channels
How is depolarization cause and what is it called?
Caused by sodium ions moving into the cell and it is called end plate potential (EPP)
Are EPPs always excitatory?
Yes, they are
Where are NMJs located?
NMJs located in the middle of a muscle fibre
In what direction does action potential spread?
Action potential spreads in opposite directions along muscle cell
What can one motor neuron action potential cause (AP)?
1 end plate potential (EPP) and 1 muscle action potential (AP) in muscle cell membrane called twitch
Explain the 9 steps of muscle contraction
- Nerve impulse reaches the synaptic end bulbs of a motor neuron
* Sodium ions travel across neuron membrane - Calcium enters the cell (synaptic end bulb)
- Triggers the release of acetylcholine (ACh) from synaptic vesicles (inside synaptic end bulb)
- ACh diffuses across the synaptic cleft (from neuron to muscle fibre)
* binds to ACh receptors on the motor end plate - Channels open allowing sodium ions into the cell – generates a muscle action potential (AP)
- Action Potential (AP) transmitted along T tubules to sarcoplasmic reticulum
- AP causes Ca2+ to be released from the sarcoplasmic reticulum
- Muscle contraction occurs
– Ca2+ binds to Troponin and changes is shape
– This pulls Tropomyosin from the active site of theActin.
– Myosin can now attach to the Actin
– ATP releases energy
– Myosin pulls the Actin filaments inwards causing ashortening of the muscle = contraction
What are 3 types of skeletal muscle fibers?
- Slow oxidative (slow twitch)
- Fast glycolytic (fast twitch)
- Fast oxidative-glycolytic (intermediate)
How are 3 types of skeletal muscle fibers classified?
They are classified based on velocity of shortening (fast or slow) and primary method of producing ATP (oxidative phosphorylation or glycolysis)
Explain slow oxidative fibres, type I
- Small diameter, many large mitochondria, appear red due to large amounts of myoglobin
- ATP generated mainly through aerobic respiration
- Develop tension slowly
- Resist fatigue
- Capable of prolonged and sustained contraction
- Associated with posture and endurance activities
Explain fast glycolytic fibres, type IIb
- Large diameter, few mitochondria, no myoglobin
(appears white) - Large amount of glycogen
- ATP generated through glycolysis.
- Fatigue rapidly
- Contract and relax quickly, providing short surge ofpower
- Associated with sprinting (allow for rapid reactions and short bursts of speed)
- Muscle size increased by exercising fast fibres
Explain fast oxidative-glycolytic fibres, type IIa
- Intermediate in diameter
- Large amounts of myoglobin and appear red
- Generate ATP through aerobic respiration and glycolysis
- Moderately resistant to fatigue
- Associated with sports such as middledistance running
What fibre type does motor unit contain?
A motor unit contains all of the same fibre type
How are motor units recruited?
Motor units are recruited in specific orders depending on requirement of speed, force,
duration of contraction
What are some effects of weight training?
Increases muscle fibre diameter—more myofibrils produced in fast fibres
Increases ability to produce ATP via glycolysis
Increases neural control and recruitment
What are some effects of endurance exercise?
Increases mitochondria
Increases blood vessels
Slightly decreases muscle size and strength compared to weight training
What are the benefits of using 3 fibre types?
Increases bone density and prevents osteoporosis
Strengthens muscles; increases balance and coordination
Increases the production of good-mood hormones,such as serotonin, oxytocin, and endorphins; possibly prevents or reverses mild depression
Helps decrease stress
Decreases inflammation in the body (moderate
exercise)
Helps prevent type 2 diabetes and cardiovascular
disease
