Chapter 10: The Muscular System

Three kinds of muscle tissue

skeletal, cardiac, and smooth

What is muscle tissue specialized for?

converting the chemical energy in ATP into the mechanical energy of motion

what do ALL muscles do?

CONTRACT

Muscle functions

movement, stability, control of openings, heat production, and glycemic control

Muscles only?

pull

Endomysium

thin sleeve of loose connective tissue around each fiber, electrically insulates each muscle fiber

Perimysium

thicker layer of connective tissue that wraps fascicles

fascicles

bundles of muscle fibers wrapped together

Epimysium

fibrous sheath surrounding entire muscle, outer surface grades into fascia; inner surface projections form perimysium

Fascia

sheet of connective tissue that separates neighboring muscles or muscle groups from each other and subcutaneous tissue

prime mover for elbow flexion

brachialis

synergist for elbow flexion

biceps brachi

antagonist for elbow flexion

triceps brachi

Orgin

end of muscle attached to bone that doesn’t move

Insertion

end of muscle attached to bone that does the moving

muscle innervation

identity of the nerve that stimulates it. This helps diagnosis nerve, spinal cord, and brainstem injuries

What will skeletal muscles never do if there is no nerve to stimulate it?

contract

spinal nerves

arise from the spinal cord, emerge though intervertebral foramina, and innervate muscles below neck

Cranial nerves

arise from the base of the brain, innervate muscles of the head and neck

Neck flexors

sternocleidomastoid

Neck extensors

trapezius

Three functional groups for muscles of the trunk

muscles of respiration, muscles that support abdominal wall, and movement of vertebral column

Inspiration

air intake

What is the primary muscle for diaphragm?

inspiration

Expiration

expelling air

external intercostals

elevate ribs, expand thoracic cavity, and create partial vacuum causing inflow of air

Internal intercostals

depresses and retracts ribs, compresses thoracic cavity, expelling air

Most prominent superficial back muscles

latissimus dorsi and trapezius

Deep muscles

erector spinae

Errector spinae

extension of vertebral column

Serratus anterior

all ribs to medial boarder of scapula, draws scapula laterally and forward; prime mover for reaching and pushing

trapezius

superficial, stabilizes scapula and shoulder, elevates and depresses shoulder apex

rhomboid major and minor

deep

Pectoralis major

flexes and adducts humerus

Latissimus dorsi

extends and adducts humerus

Deltoid

rotates and abducts arm

teres major

extension and medial rotation of humerus

Rotator cuff muscles

supraspinatus, infraspinatus, teres minor, and subscapularis

Principal flexor on the forearm

barchialis

synergistic flexors on the forearm

biceps brachii and brachioradialis

powerful supinators on the forearm

biceps brachii

Principal extensor on the forearm

triceps brachii

anterior group of wrist and hand

flexor carpi radialis, palmares longus, flexor carpi lunaris, and flexor digitorium superficialis

posterior group of wrist and hand

extensor carpi lanais, extensor capri radialis longus and brevis, extensor digitorium

Iliacus

flexes thigh at hip

Psoas major

flexes thigh at hip, Aries from lumbar vertebrae

laterior and posterior muscles of the hip

tensor fasciae latae

gleuteus medius

abduction of hip

medial compartment of thigh

adductor longus, adductor Magnus, and gracilis

Sartorius

longest muscle in body

Posterior compartment of the thigh

contains hamstrings

gastrocnemius

plantar flexes foot, flexes knee

soleus

planter flexes foot

Tibialis posterior

inverts foot

fibulas longus

everts foot, provides lift