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46 terms

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