Chapter 10:Muscular System

Question 1

Muscle Tissue

Answer 1

is a primary tissue type specialized for movement

• movement of body, maintain stability (posture)
• soft tissue support
• guard body openings
• thermoregulation

Question 2

Muscular system

Answer 2

references skeletal muscle:

• muscles of the head, neck and trunk
• muscles acting on upper and lower limbs and their girdles

Question 3

Answer 3

Muscle Tissue

Question 4

Skeletal Muscle Shapes

Answer 4

are classified according to the orientation of the fascicles

Question 5

5 classifications of muscles:

Answer 5

parallel muscles have fascicles parallel to long axis of the muscle

• biceps brachii and rectus abdominis

convergent muscles are broad at origin and taper to a narrow insertion

• pectoralis major

pennate muscles have fascicles insert obliquely on a tendon; develop more tension than parallel muscles

• unipennate, bipennate or multipennate
• extensor digitorum, rectus femoris and deltoid

circular muscles (sphincter) “ring” around a body opening

• orbicularis oculi, pyloric valve and anal sphincters

Question 6

Fascicle orientation affects

Answer 6

power, range, and speed of muscle movement

Question 7

Answer 7

Skeletal Muscle Shapes

Question 8

Leverst

Answer 8

Levers are rigid objects that rotates around a fixed point called a fulcrum

• provides mechanical advantage when effort overcomes resistance
• mechanical advantage increases output of force (power) or move objects faster (speed)
• bones are levers, joints are fulcrums, and muscle is effort

Question 9

Three kinds of levers:

Answer 9

first-class - fulcrum lies between applied force (AF) and the load (L)

• output and speed usually in balance

second-class - load (L) is between applied force (AF) and fulcrum

• more output but less speed

third-class - applied force (AF) is between load (L) and fulcrum

• less output but more speed

Question 10

Muscles have 1 fixed point of attachment (origin) and 1 moving point of attachment (insertion)

Answer 10

• origin is usually proximal to insertion
• most muscles originate or insert on the skeleton

Question 11

Origin and insertion are relative terms;

Answer 11

action of muscle determines both points

Question 12

Actions are produced by

Answer 12

muscle contraction
muscles work in groups to maximize efficiency

Question 13

3 types of coordinated muscle actions:

Answer 13

-prime mover (agonist) produces most of force

-synergist aids the prime mover
stabilizes the nearby joint and modifies/assists the direction of movement

-antagonist opposes the prime mover
prevents excessive movement and injury

Question 14

Muscles work in

Answer 14

pairs and in opposition

Question 15

Muscles of the face are

Answer 15

small and insert into the dermis

• innervated by facial nerve (CN VII)
• paralysis causes face to sag (Bells palsy)

Question 16

Muscles of the face:

Answer 16

frontalis
elevates eyebrows
obicularis oculi
closes eyes
buccinator
moves food around the cheeks
obicularis oris
closes/protrudes lips
platysma
tenses neck (and depresses mandible)

Question 17

Answer 17

Muscle of Facial Expression

Question 18

Extra-ocular muscles

Answer 18

(extrinsically) responsible for eye movement
* muscles insert on sclera of eye

Question 19

6 eye muscles:

Answer 19

inferior rectus
eye looks down
medial rectus
eye looks medially
superior rectus
eye looks up
lateral rectus
eye looks laterally
superior and inferior obliques
eye looks laterally up/down

Question 20

Muscles of mastication

Answer 20

attach to the mandible

• responsible for chewing

Question 21

Muscles of mastication:

Answer 21

temporalis
elevates mandible
masseter
elevates mandible
strongest jaw muscle
medial pterygoid
produces lateral swinging of jaw

Question 22

Tongue

Answer 22

shifts food onto teeth and pushes it into pharynx

• muscles connect tongue to hyoid, styloid process, palate and inside of chin

Question 23

Muscles of tongue:

Answer 23

genioglossus

hyoglossus

Question 24

Muscles of the neck

Answer 24

are responsible for movement or swallowing

Question 25

Muscles of the neck:

Answer 25

**digastric** opens mouth widely **mylohyoid** elevates floor of mouth initial stage of swallowing **sternocleidomastoid** upward tilt of head laryngeal/pharyngeal elevators and constrictors

Question 26

Erector spinae group

Answer 26

Erector spinae group spans the vertebral column **3 columns of muscle** *iliocostalis lumborum longissimus thoracis spinalis thoracis*

Question 27

Semispinalis groups run vertebrae to vertebrae and extends vertebral column name the three groups

Answer 27

semispinalis capitis semispinalis cervicis semispinails thoracis

Question 28

Diaphragm

Answer 28

is a muscular dome between thoracic and abdominal cavities - flattens during contraction * increases dimension of the thorax to draw air into the lungs and raises the abdominal pressure - helps expel urine/feces and aids in childbirth

Question 29

Intercostal muscles

Answer 29

* *Intercostal muscles** - externals extend down and anteriorly from rib to rib * pull ribcage up and outward during inspiration - internals extend up and anteriorly from rib to rib * pull ribcage downward during forced expiration

Question 30

Trunk muscles compress the abdomen, depress the ribs, and flex the spine

Answer 30

**external oblique** runs downward towards the anterior **internal oblique** runs upwards towards the anterior **rectus abdominis** is vertical and runs from xiphoid process to pubis symphysis **transverse abdominis** has a horizontal fiber orientation and is the deepest layer

Question 31

Muscles of the pelvic floor (perineum)

Answer 31

support the viscera and control movement of material passing through urethra and anus - diamond-shaped region bounded by pubic symphysis, coccyx and ischial tuberosities * penetrated by anal canal, urethra and vagina (female) - anterior is urogenital triangle; posterior is anal triangle

Question 32

Hernias

Answer 32

Hernias are protrusions of viscera through muscular wall of abdominopelvic cavity

Question 33

name the 3 hernia types

Answer 33

**inguinal hernia (most common)** viscera enter inguinal canal or even the scrotum rare in women **hiatal hernia** stomach protrudes through diaphragm into thorax overweight people over 40 **umbilical hernia** viscera protrude through the navel

Question 34

Muscles of the pectoral girdle

Answer 34

originate on axial skeleton and insert onto clavicle or scapula -allow for rotation, elevation, protraction, and retraction of shoulder

Question 35

Important pectoral girdle muscles:

Answer 35

**pectoralis minor (anterior)** **serratus anterior (anterior)** **trapezius (posterior)** **rhomboideus minor (posterior)** **rhomboideus major (posterior)**

Question 36

Muscles acting on humerus are _____ \_\_\_\_\_in flexion and extension

Answer 36

prime movers

Question 37

axial group

Answer 37

**pectoralis major** produces forward swing of arm **latissimus dorsi** produces backward swing of arm

Question 38

scapular group

Answer 38

* **deltoid** flex, extend, and abduct arm * subscapularis medially rotate shoulder * **infra-** and **supra- spinatus** abduct shoulder (supra); laterally rotate shoulder (infra

Question 39

Muscles of the rotator cuff

Answer 39

help reinforce the joint capsule

Question 40

2 groups: of rotator cuff muscles

Answer 40

**posterior scapula** supraspinatus infraspinatus teres minor **anterior scapula** subscapularis

Question 41

Muscles acting on the elbow

Answer 41

are capable of flexion, extension, pronation, and supination

Question 42

Muscles acting on the elbow

Answer 42

**Principal flexors** biceps brachii brachialis synergist **Prime extensor** triceps brachii

Question 43

Muscles of the forearm

Answer 43

flex/extend wrist and act on the fingers

Question 44

Muscles of anterior forearm (flexion): =

Answer 44

``` **flexor digitorum profundus** inserts into (distal) fingers **flexor pollicis longus** inserts into thumb ```

Question 45

Muscles of posterior forearm (extension):

Answer 45

**extensor digitorum** inserts into fingers spreads fingers apart when extending **extensor pollicis brevis** inserts into thumb

Question 46

Muscles acting on hip are responsible for:

Answer 46

flexion and extension of thigh stabilization of trunk on femur

Question 47

Anterior hip:

Answer 47

**iliopsoas** muscle (major hip flexor) * iliacus portion arises from iliac fossa * psoas portion arises from lumbar vertebrae

Question 48

Posterior hip:

Answer 48

**gluteus maximus** (prime hip extensor) * forms mass of the buttock provides most of lift when you climb stairs **gluteus medius and minimus** * shifts body weight when foot is lifted

Question 49

Muscles acting on femur are responsible

Answer 49

for adduction and flexion

Question 50

Medial muscles of femur:

Answer 50

**adductor magnus** extensor and adductor **pectineus, adductor brevis and longus** flexors and adductors **gracilis** flexor of knee

Question 51

Muscles acting on knee

Answer 51

Muscles acting on knee (extension) and posterior thigh (flexion)

Question 52

Muscles Acting on the Knee Anterior group:

Answer 52

**quadriceps femoris** rectus femoris vastus medialis and lateralis

Question 53

Muscles Acting on the Knee Posterior group:

Answer 53

**hamstrings** * biceps femoris * semitendinosus * popliteus unlocks knee to allow for flexion **sartorius** (anterior) * synergist in knee flexion

Question 54

Muscles of the leg

Answer 54

flex and extend foot and toes

Question 55

Muscles of the Leg anterior

Answer 55

**tibialis anterior** * flexion of foot extensor digitorum longus * extends toes extensor hallicus longus * extends big toe

Question 56

Muscles of the Leg. Posterior (largest)

Answer 56

**gastrocnemius** * extension and inversion of foot **soleus** * extension of foot

Question 57

Intrinsic muscles of foot

Answer 57

Intrinsic muscles of foot originate on the foot and have four layers * support for arches; abduct, adduct, and flexes the toes

Question 58

Important muscles of foot:

Answer 58

**dorsal** * extensor hallucis brevis extends big toe; synergist to extensor hallucis longus * extensor digitorum brevis extends all toes; synergist to extensor digitorum longus **plantar** * flexor hallicus brevis flexes big toe * flexor digitorum brevis flexes all toes

Question 59

Fascia

Answer 59

Fascia are connective tissue partitions within the body

Question 60

deep fascia

Answer 60

``` found between adjacent muscles superficial fascia (hypodermis) is adipose between skin and muscles ```

Question 61

Deep fascia functions to compartmentalize muscle

Answer 61

- each muscle has a characteristic blood and nerve supply * **compartment syndrome** results from trauma that yields bleeding into a compartment increased pressure from bleeding can lead to muscle paralysis or death within 2-4 hours

Question 62

Athletic injuries of muscular system occur

Answer 62

under sudden and intense stress anyone is susceptible

Question 63

Athletic Injuries common injuries include

Answer 63

* * charley horse * shinsplints * pulled hamstrings * tennis elbow

Question 64

treat atheletic injuries with RICE

Answer 64

Treat with rest, ice, compression and elevation

Question 65

Dangerous misconception in atheletic injuries

Answer 65

“No pain, no gain”