Exam 3- Criswell
Carpel tunnel
tight space between the flexor retinaculum and the carpal bones • Flexor tendons passing through the tunnel are enclosed in tendon sheaths • Enable tendons to slide back and forth quite easily
Satellite cells
unspecialized myoblasts remaining between the muscle fiber and endomysium • Play a role in repair of damaged skeletal muscle tissue
Intrinsic muscle
Entirely contained within a region, such as the hand
Shwann cell
Envelops and isolates NMJ
flexor retinaculum
bracelet-like fibrous sheet, passed under by flexor tendons crossing the wrist
Glycogen
carbohydrate stored to provide energy for exercise Skeletal muscle fibers
Triangular (convergent)
(Fascicles and muscle shapes) Broad at one end and narrow at other
Pennate
(Fascicles and muscle shapes) Feather-shaped; include unipennate, bipennate, multipennate
Circular (sphincter)
(Fascicles and muscle shapes) Form rings around body openings
Fusiform
(Fascicles and muscle shapes) Thick in middle; tapered at ends, terminate in tendons
Parallel
(Fascicles and muscle shapes) Uniform width
Transverse abdominal
(Muscles of abdominal wall) - Compresses abdominal contents but does not contribute to movements of vertebral column
Rectus abdominis
(Muscles of abdominal wall) - Flexes lumbar region and produces forward bending at waist
Extrinsic muscles of tongue
(Muscles of chewing and swallowing) - Pushes food between molars for chewing (mastication) - Forces food into the pharynx for swallowing (deglutition) - Crucial importance to speech
Intrinsic muscles of tongue
(Muscles of chewing and swallowing) - Vertical transverse, and longitudinal fascicles
Perineum
(Muscles of pelvic floor) - Diamond-shaped region between the thighs - Bordered by 4 bony landmarks - Pubic symphysis - anteriorly - Coccyx posteriorly - Ischial tuberosities laterally
Action
(functional groups of muscles) Effects of muscle -> produce or prevent movement 4 categories depending on action
Origin
(muscle attachment) Bony attachment at stationary end of muscle
Insertion
(muscle attachment) Bony attachment to mobile end of muscle
retinaculum
(muscle attachment) Connective tissue band that tendons from separate muscle pass under
Belly
(muscle attachment) Thicker, middle region of muscle between origin and insertion
Intermuscular septa
(muscle compartment) Very thick fascia that separate one compartment from another
Internal intercostals
(muscle of respiration) - Depresses & retracts ribs - Compresses thoracic cavity
External abdominal oblique
(muscles of abdominal wall) - Unilateral contraction causes contralateral rotation of waist
External intercostals
(muscles of respiration) - Elevates ribs - Expands thoracic cavity
Diaphragm
(muscles of respiration) muscular dome between thoracic & abdominal cavities
Extrinsic muscle
Acts on a designated region but has attachment elsewhere.
Slow twitch (slow oxidative SO, red or type 1 fibers)
Adapted for endurance; resist fatigue by oxidative (aerobic) ATP production • Important for muscles that maintain posture (e.g. erector spinae of back, soleus of calf) • Thin cells with abundant mitochondria, capillaries, myoglobin (deep red color) • Grouped in small motor units controlled by easily excited motor neurons = precise movements
Spinal nerves
Arise from spinal cord - Named based on adjacent vertebra (Ex. T6, L4, S2) - Emerge through intervertebral foramina; split into anterior and posterior ramus - Innervate muscle below the neck
cranial nerves
Arise from the base of the brain - Emerge through skull foramina - Innervate the muscle of the head and neck - Numbered CN I to CN Xii= 12 pairs
myogram
Behavior of whole muscle a chart of the timing and strength of a muscle's contraction
Twitch
Behavior of whole muscle a quick cycle of contraction and relaxation when stimulus is at threshold or higher
Latent period
Behavior of whole muscle very brief delay between stimulus and contraction • Time required for excitation, excitation-contraction coupling, and tensing of elastic components of muscle (generating internal tension)
Threshold
Behavior of whole muscle minimum voltage necessary to generate an action potential in the muscle fiber and produce a contraction
Fascicles
Bundles of muscle fibers wrapped together
Muscle fiber
Capillaries branch through the endomysium to reach every _____
Prime mover
Category depending on action Agonist -Produces most of force during a joint action Ex. Brachialis
Synergist
Category depending on action Muscle that aids the prime mover - Stabilizes the nearby joint; modifies the direction of movement; may contribute additional force Ex. Biceps brachii
Antagonist
Category depending on action Opposes the prime mover - Relaxes to give prime mover control over an action - Prevents excessive movement & injury Ex. Triceps brachii
Fixator
Category depending on action Prevents movement of bone Muscle that holds scapula firmly in place Ex. Rhomboids
Tendons
Connects muscles to bone
Sarcoplasm
Cytoplasm of a muscle fiber Skeletal muscle fibers
A band
Dark; thick (myosin) filaments
Relaxation
Diaphragm rises - Shrinks the thoracic cavity (expiration)
Suprahyoid group
Digastric, Geniohyoid, Mylohyoid, Stylohyoid • Concerned with aspects of chewing, swallowing, & vocalizing
three-quarters
During heavy exercise, total cardiac output rises and the muscular system's share is more than ____
Characteristics of muscle
Excitability (responsiveness) - to chemical signals, stretch, & electrical changes across plasma membrane Conductivity - local change triggers a wave of excitation that travels along the muscle fiber Contractility - shortens when stimulated Extensibility - capable of being stretched between contractions Elasticity - returns to original resting length after being stretched
Epimysium
Fibrous sheath surrounding entire muscle - Outer surface grades into fascia; inner surface projection form perimysium
Thenar group
Fleshy mass at base of thumb • Adductor pollicis • Abductor pollicis brevis • Flexor pollicis brevis • Opponens pollicis
4 different muscles shapes
Fusiform; spindle-shaped, allowing large range of motion and good speed of contraction. Ex. Biceps Brachii Pennate: muscle fibers that run diagonally towards central tendon. Allows for greater force generation at the expenses of some ROM. Ex. Rectus femoris Circular: Ring-shaped allowing to constrict or close openings. Ex. Orbicular Oris Triangular: Triangle shaped allowing for multiple directions of pull and abduction. Ex. Deltoid
Sphincters
Internal muscle rings
Muscular system
Movement from place to place; move body parts Move body contents in breathing, circulation, and digestion Aid in communication Stability -Maintain posture, stabilize joints Control opening and passageways Heat production by skeletal muscles Glycemic control-muscles store glucose
I band
Light; think (actin) filaments
H band
Lighter region in middle of A band; thick filament only
Direct (fleshy) attachment to bone
Little separation between muscle and bone Muscle seems to emerge directly from bone Ex: Margins of brachialis, lateral head of triceps brachii
M line
Middle of H band; transverse protein complex that links thick filaments
Inguinal hernia
Most common type of hernia (rare in women) • Viscera enters inguinal canal or even the scrotum
Antagonistic pairs
Muscles that act on opposite sides of joint
1.24 L
Muscular system receives about ___ of blood per minute at rest (1/4 of the blood pumped by the heart)
Infrahyoid group
Omohyoid, Sternohyoid, Thyrohyoid, Sternothyroid • Fix hyoid bone from below, allowing suprahyoid muscles to open mouth
Anaerobic fermentation
One of the main pathways of ATP synthesis - enables cells to produce ATP in the absence of oxygen; yields little ATP and toxic lactate, which needs to be disposed of by the liver and speeds up muscle fatigue
Aerobic respiration
One of the main pathways of ATP synthesis produces far more ATP; does not generate lactate; requires a continual supply of oxygen
Sarcolemma
Pasma membrane of a muscular fiber Skeletal muscle fibers
4 of 6 lateral rotators of the hip
Piriformis: anterior surface of sacrum. Inserts on upper part of the greater trochanter of femur Obturator internus: joins the other lateral rotators by inserting on the greater trochanter of femur Superior Gemellus: Joins its twin, inferior gemellus, and inserts on a tendon that attaches to the greater trochanter of femur Quadratus femoris: Inserts on greater trochanter of the femur along with other lateral rotators
Myoglobin
Red pigment, provides oxygen for muscle activity Skeletal muscle fibers
Fascia
Sheet of connective tissue that separates neighboring muscles or muscle groups each other and subcutaneous tissue
Multiple nuclei
Skeletal muscle fibers flattened nuclei pressed against the inside of the sarcolemma
Nerve
Skeletal muscles cannot contract unless stimulated by a ____ - If ____ connections are severed, muscle is paralyzed
Different functional classifications of muscles
Skeletal muscles: Voluntary muscle that make up the bulk of our muscles and are attached to bones by tendons. Ex. Bicep Brachii Cardiac muscles: Involuntary muscles that form the myocardium. Responsible for rhythmic contractions of heart that pump blood throughout body. Ex. Myocardium Smooth muscles: Involuntary muscles found in walls of hollow organs. Responsible for peristalsis, constriction, and dilation of blood vessels. Ex. Spinchter muscles
Hiatal hernia
Stomach protrudes through diaphragm into thorax • Overweight people over 40
4 rotator cuff muscles
Supraspinatus: Located on top of shoulder blade and attaches to upper portion of humerus Infraspinatus: Located beneath the supraspinatus on back of shoulder blade, attaches to back of humerus Teres minor: Small muscle situated beneath the infraspinatus and attaches to lower part of humerus Subscapularis: Occupying the underside of the shoulder blade, attaches to the lesser tuberosity of the humerus
Neuromuscular junction
Synapse- Point where a nerve fiber meets its target cell Neuromuscular junction (NMJ)/ motor end plate- when target cell is a muscle fiber Axon terminal- swollen end of nerve fiber that contains synaptic vesicles
Aponeurosis
Tendon is a broad, flat sheet (muscle attachment)
Perimysium
Thicker layer of connective tissue that wraps fascicles - Carries nerves, blood vessels, and stretch receptors
Endomysium
Thin sleeve of loose connective tissue around each fiber (cell) - Allows room for capillaries and nerve fibers - Provides chemical environment for muscle fiber
Umbilical hernia
Viscera protrudes through the navel
Plexus
Web-like network of spinal nerves adjacent to the vertebral column
Z disc
Z line Provides anchorage for thick and elastic filaments Bisects I band
Contraction
_____ flattens diaphragm Enlarges thoracic cavity (inspiration)
Voltage (electrical potential)
a difference in electrical charge from one point to another
Plasticity
ability to adjust its tension to the degree of stretch • A hollow organ (e.g. bladder) can be greatly stretched yet not become flabby when empty
Resting membrane potential
about −90 mV in skeletal muscle cells • Maintained by sodium-potassium pump
Hypothenar group
fleshy base of the little finger • Abductor digiti minimi • Flexor digiti minimi brevis • Opponens digiti minimi
Synaptic cell
gap between axon terminal and sacrolemma
Midpalmar group
hollow of palm • Dorsal interosseous muscles (4) • Palmar interosseous muscles (3) • Lumbricals (4 muscles)
Myofibrils
long protein cords occupying most of sarcoplasm Skeletal muscle fibers
Sartorius
longest muscle in the body
isotonic muscle contraction
muscle changes in length w/ no change in tension
Eccentric contraction
muscle lengthens as it maintains tension (example: slowly lowering weight)
Isometric muscle contraction
muscle produces internal tension, but external resistance causes it to stay the same length • Can be a prelude to movement when tension is absorbed by elastic component of muscle • Important in postural muscle function and muscle-joint stabilization
Concentric contraction
muscle shortens as it maintains tension (example: liftingweights)
9
muscles cross the shoulder joint and attach to the humerus
Motor unit
one nerve fiber and all the muscle fibers innervated by it
Quadriceps femoris
prime mover of knee extension, most powerful muscle in the body Has 4 heads: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius
Carpel tunnel syndrome
repetitive motions of wrist and fingers cause tissues to become inflamed, swollen, or fibrotic • Those motions put pressure on the median nerve and cause inflammation • Symptoms include tingling and muscular weakness in the palm and medial side of the hand
Sarcomere
segment of a myofibril from Z disc to Z disc • Functional contractile unit of muscle fiber
Myoblasts
stem cells that fused to form each muscle fiber early in development Skeletal muscle fibers
Skeletal muscles
voluntary, striated muscle usually attached to bones Striations — alternating light and dark transverse bands - Results from arrangement of internal contractile proteins Voluntary — usually subject to conscious control -Muscle cell is a muscle fiber (myofiber) — as long as 30 cm - Packed w/ units called myofibrils
Peristalsis
waves of contraction triggered by food distending esophagus or feces distending colon
Fast-twitch, (fast glycolytic (FG), white, or type II fibers)
•Thick and strong fibers adapted for quick responses but not fatigue resistance •Important for quick and powerful muscles: eye and hand muscles, gastrocnemius of calf and biceps brachii •Utilize glycolysis and anaerobic fermentation for energy; lack of myoglobin gives them pale appearance •Grouped in large motor units controlled by less excitable neurons = powerful movements