1 / 79
two ways muscles can work as a system
❮ prev next ❯
1 / 79
together or in opposition whatever one muscle (or group of muscles) does, another muscle (or group of muscles) undoes
❮ prev next ❯

terms list

two ways muscles can work as a system
together or in opposition whatever one muscle (or group of muscles) does, another muscle (or group of muscles) undoes
as muscles shorten, the ______ moves toward the _______
insertion origin
approximately how many muscles are there in the human body?
function of muscles
-move body parts -move contents of organs (smooth and cardiac muscle) -maintain posture and prevent movement -communication (speech, expressions and writing) -control body openings -heat production
prime movers
provide the major force for producing a specific movement
oppose or reverse a particular movement
-add force to a movement -reduce undesirable or unnecessary movement
synergists that immobilize a bone or muscle's origin
naming of muscles based on relative size
maximus (largest), minimus (smallest), longus (long)
naming of muscles based on direction of fibers
rectus (fibers run straight), transversus, and oblique (fibers run at angles to a defined axis)
naming of muscles based on number of origins
biceps (two origins) and triceps (three origins)
the bundles of myocytes surrounded by the perimysium membrane see p 4
parallel fascicles
fascicles run parallel to the long axis of the muscle (e.g. sartorius)
fusiform fascicles
spindle-shaped muscles (eg biceps brachii)
pennate fascicles
short fascicles that attach obliquely to a central tendon running the length of the muscle (e.g. rectus femoris)
convergent fascicles
fascicles converge from a broad origin to a single tendon insertion (e.g. pectoralis major)
circular fascicles
fascicles are arranged in concentric rings (e.g. obicularis oris-muscles around mouth, eyes)
direct attachment of muscle
epimysium of muscle is continuous with periosteum of bone relatively uncommon (intercostal muscles)
indirect attachment of muscle
epimysium collects into a tendon or aponeurosis that attaches to periosteum via perforating fibers most common (biceps brachii, gastrocnemius, etc)
intrinsic muscles
contained within the region that is moved by their contraction
extrinsic muscles
move body parts outside of the region where they are found
a rigid bar that moves on a fulcrum, or fixed point
force applied to a lever
resistance moved by the effort
effort x length of effort arm (force x distance) =
load x length of load arm (resistance x distance)
power lever
lever that operates at a mechanical advantage
speed lever
lever operates at a mechanical disadvantage
first class lever
fulcrum between load and effort, speed lever
second class lever
load between fulcrum and effort, speed lever
third class lever
effort is applied between fulcrum and load, speed lever
epicranius (occipitofrontalis)
bipartite muscle consisting of the: frontalis, occipitalis, galea aponeurotica (cranial aponeurosis connecting frontalis and occipitalis)
frontalis and occipitalis have what motions
alternate actions of pulling scalp forward and backward
how many muscles are involved in lifting the eyebrows, flaring the nostrils, opening and closing eyes and mouth, and smiling?
what are the facial muscles innervated by
cranial nerve VII (facial nerve)
where do facial muscles insert
skin (rather than bone)
see muscle diagrams in notes
major head flexor
synergists to head flexion
suprahyoid and infrahyoid
lateral head movements are accomplished by
sternocleidomastoid and scalene muscles
head extension accomplished by
deep splines muscles and superficial trapezius
prime mover of back extension
erector spinae
erector spinae consist of:
three columns on each side of the vertebrae- iliocostalis, longissimus, spinalis
lateral bending of the back is accomplished by unilateral contraction of what muscles
erector spinae muscles (iliocostalis, longissimus, spinalis)
other deep back extensors include the
semispinalis muscles and quadratus lumborum
primary function of deep thoracic muscles is to
promote movement for breathing
external intercostals
more superficial layer that lifts the rib cage and increases thoracic volume to allow inspiration
internal intercostals
deeper layer that aids in forced expiration
most important muscle for inspiration at rest
what is the abdominal wall made up of?
four paired muscles (internal and external obliques, transversus abdominus, and rectus abdominus), their fasciae, and their aponeuroses
fascicles of the abdominal muscles run at what angles to one another, giving the abdominal wall added strength
right and oblique
what do the abdominal muscles do
-involved with lateral flexion and rotation of trunk -help promote urination, defecation, childbirth, vomiting, coughing, and screaming
prime movers of shoulder elevation
trapezius and levator scapulae
how many muscles cross shoulder joint and insert into humerus
prime mover of arm flexion
pectoralis major
prime movers of arm extension
latissimus dorsi and posterior fibers of the deltoid
prime movers of arm abduction
middle fibers of the deltoid
rotator cuff muscles
supraspinatus, infraspinatus, teres minor, and subscapularis
functions of rotator cuff muscles
main: to reinforce the capsule of the shoulder secondary: as synergists and fixators
prime mover of forearm extension
triceps brachii
chief forearm flexors
brachialis and biceps brachii
what does brachioradialis of forearm do?
acts as a synergist and helps stabilize elbow
what do muscles of anterior forearm do?
primarily flexors of the wrist and fingers
what do muscles of posterior forearm do?
primarily extensors of the wrist and fingers
where in the hand are there muscles?
in the palm of the hand (none on the dorsal side)
what do muscles of the hand do?
control precise movements (e.g. threading a needle) main abductors and adductors of fingers produce opposition
what is opposition?
movement of thumb toward little finger
what motions does the ball-and-socket hip joint permit
flexion, extension, abduction, adduction, circumduction, and rotation
most important thigh flexors
iliopsoas (prime mover), tensor fasciae latae, and rectus femoris
muscles that assist in thigh flexion
medially located adductor muscles and sartorius
thigh extension is primarily effected by
the hamstring muscles (biceps femurs, semitendinosus, and semimembranosus) forceful extension is aided by the gluteus maximus
sole extensor of the knee
quadriceps femoris
what muscles flex the knee
hamstring muscles
anterior muscles of the leg and their functions
tibialis anterior, extensor digitorum longus, extensor hallucis longus, and fibularis tertius primary toe extensors and ankle dorsiflexors
function of lateral compartment muscles of the lower leg
plantar flex and evert the foot
lateral muscles of lower leg
fibularis longus and fibularis brevis
function of posterior muscles of lower leg
flex foot and toes
posterior muscles of lower leg
gastrocnemius, soleus, tibialis posterior, flexor digitorum longus, flexor hallucis longus
function of foot muscles
help flex, extend, abduct, and adduct the toes support the arch of the foot
what is the single, dorsal foot muscle, and what does it do
extensor digitorum brevis extends toes

more from user

Anatomy Test 4

5 items en en

Biochem Test 3

30 items en en

Anatomy Test 3

108 items en en

Biochem Test 2

86 items en en

Biochem Test 1

203 items en en


30 items en en

Anatomy: Back

177 items en en

Health Psych Final

174 items en en

Soc Final Study Guide

59 items en en

Bio Test 3

216 items en en

Chapter 7

84 items en en

Genetics test 3

61 items en en


Anatomy chapter 10-test 3

82 items en en

BMSP 2135 Ch 10

99 items en en

Chapter 11: Muscles of the Body

94 items en en