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