CH 10 The muscular system

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1the term "prime mover" is used in the business world to indicate people that get things done-the movers and shakers. what is it physiological meaning?

refers to the muscle that bears the most responsiblity for causing a particular movement

2what criteria are used in naming each of the following muscles: iliacus, adductor brevis, quadriceps femoris?

illiacus-overlies the iliac bone, the adductor-brevis is a small (size) muscle that adducts (movement caused) the thigh, the quadriceps-(4 heads) femoris muscles follows the course of the femur

4 which of the three lever systems involved in muscle mechanics would be the fastest lever-first, second or third class?

3rd class levers are the fastest levers...

5what benefit is provided by a lever that operates at a mechanical advantage?

allows the muscle to exert less force than the load being move...

How are skeletal muscles arranged ?

in opposing groups across body joints so that one group can reverse or modify the action of the other

What are muscles classified as?

prime movers or agonists (bear the chief responsibility for producing movement); antagonists (reverse, or oppose the action of another muscle; synergists (aid a prime mover by effecting the same action, stabilizing joints, or preventing undesirable movements); and fixators (function to immobilize bone or muscle origin)

What is the criteria in naming muscles?

location, shape, relative size, fiber (fascicle) direction, number of origins, attachment sites (origin/insertion), action.

what are common patterns of fascicle arrangement?

parallel, fusiform, pennate, convergent and circular. muscles with fibers that run parallel to the long axis of muscle shortne most, stocky pennate muscles shorten little but are the most powerful muscles

What is a lever

a bar that moves in a fulcrum. when an effort is applied to the lever, a load is moved. in the body,bones are the levers, joints are the fulcrums and the effort is exerted by skeletal muscles at their insertions

How do 1st class levers operate?

(effort-fulcrum-load) operate at a mechanical advantage or disadvantage.

how does a 2nd class lever operate?

(fulcrum-load-effort) all operate at a mechanical advantage

how does a 3rd class lever operate?

(fulcrum-effort-load) always operate at a mechanical disadvantage. most skeletal muscles of the body act in third class lever systems

Muscles of the head that produce facial expression

tend to be small and to insert into soft tissue (skin and other muscles) rather than into bone. these muscles open and close the eyes and mouth, compress the cheeks, allow smiling and other types of facial language

Muscles of the head involved in mastication

include the masseter and tempralis that elevate the mandible and two deep muscle pairs that promote grinding and sliding jaw movements. extrinsic muscles of the tongue anchor the tongue and control its movements

Deep muscles of the anterior neck

promote swallowing movements, including elevation/depression of the hyoid bone, closure of the respiratory passages, and peristalsis of the pharnyx

Neck muscles and deep muscles of the vertebral column

promote head and trunk movements. the deep muscles of the posterior trunk can extend large regions of the vertebral column (and head) simultaneously. head and flexion and rotation are effect by the anteriorly located sternocleidomastoid and scalene muscles

movements of quiet breathing

are promoted by the diaphragm and the external intercostal muscles of the thorax. downward movement of the diaphragm increase intra-abdominal pressure

the four muscle pairs forming the abdominal wall are layered like plywood to form

form a natural muscular girdle that protects, supports and compresses abdominal contents. the muscles also flex and laterally rotate the trunk

muscles of the pelvic floor and perineum support

the pelvic viscera, resist increases in intra-abdominal pressure, inhibit urination and defecation, and aid erection

except for the pectoralis major and the latissimus dorsi, the superficial muscles of the thorax act to

fix or promote movements of the scapula. scapular movements are effected primarily by posterior thoracic muscles

nine muscles cross the shoulder joint to effect movements of the humerus

of these 7 originate on the scapula and two arise from the axial skeleton. four muscles contribute to the "rotator cuff" helping to stabilize the mulitaxial shoulder joint. generally speaking, muscles located anteriorly flex, rotate, and adduct the arm. the deltoid muscle of the shoulder is the prime mover of shoulder abduction

muscles causing movements of the forearm form the flesh of the arm, anterior arm muscles are

forearm flexors, posterior muscles are forearm extensors

movements of the wrist, hand and fingers are affected mainly by

muscles originating on the forearm. except for the two pronator muscles, the anterior forearm muscles are wrist and or finger flexors, those of the posterior compartment are wrist and finer extensors

the intrinsic muscles of the hand aid in

precise movements of the fingers and in opposition, which helps us grip things in our palms.. these small muscles are divided into thenar, hypothenar, and midpalmer groups

muscles crossing the hip and knee joints effect

thigh and leg movements. anterior compartment muscles are largely ankle dorsiflexors. lateral compartment muscles are plantar flexors and foot everters. those of the posterior leg are plantar flexors

the intrinsic muscle of the foot support

the foot arches and help move the toes. most occur in the sole, arrange in four layers. they resemble the small muscles in the palm of the hand.

1a muscle that assists an agonist by causing a like movement or by stabilizaing a joint over which an agonist acts is

synergist

the arrangement of muscle fibers in which the fibers are arranged at an angle to a central longitudinal tendon is

pennate

3.1squints the eyes

orbicularis oculi

3.2raises the eyebrows

frontal belly of epicranius

3.3smiling muscle

zygomaticus

3.4puckers the lips

orbicularis oris

3.5pulls the scalp posteriorly

occipital belly of epicraniua

4the prime mover of inspiration is the

diaphragm

5 the arm muscle that both flexes the elbow and supinates the forearm is the

biceps brachii

6the chewing muscles that protrude the mandible and produce side-to-side grinding movements are the

pterygoids

muscles that depress the hyoid bone and larynx include all but the

geniohyoid

8intrinsic muscles of the back that promote extension of the spine (or head) include all but

scalene muscles

several muscles act to move and or stabilize the scapula. which of the following are small rectangular muscles that square the shoulders as they act together to retract the scapula? levator, scapulae, rhomboids, serratus anterior, traezius

rhomboids

10 the quadriceps include all but vastus lateralis, vastus intermedius, vastus medialis, biceps femoris, rectus femoris

biceps femoris

a prime mover of hip flexion is the

iliopsoas

13 muscles that cause plantar flexion include all but the gastrocnemius, soleus, tibialis anterior, tibialis posterior, fibularis muscles

tibialis anterior

12 the prime mover of hip extensions against resistance is the

gluteus maximus

14 in walking, which two lower limb muscles keep the forward swinging foot from dragging on the ground?

gluteus medius and tibialis anterior

15 what criteria are used in naming the gluteus medius?

relative size and muscle location

16 which of the following is a large, deep muscle that protracts the scapula during punching? serratus anterior, rhomboids, levator scapulae, subscapularis

serratus anterior

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