CH 4: Muscular System Flashcards
responsible for body
movements, stabilizing joints, and generating
heat.
muscles
Muscles generate the force required to
cause movement by
contracting
a process in which proteins inside the muscle fibers overlap more than when they are at rest.
contracting
muscle function
- Produce Movement
- Maintain Posture and Body Position
- Stabilize Joints
- Generate Heat
- Additional Functions
_____ are packaged into organs
called skeletal muscles that attach to the skeleton.
Skeletal muscle fibers
Skeletal muscle fibers are packaged into organs called ____ that attach to the skeleton.
skeletal muscles
cover our bone and cartilage framework, they help form the smooth contours of the body
skeletal muscle
Skeletal muscle fibers are large, ______, multinucleate cells.
cigarshaped
Skeletal muscle is also known as (2)
striated muscle
voluntary muscle
no striations and is involuntary
Smooth muscle
difference in tissue and function
- skeletal muscle and smooth muscle
skeletal muscle
-striated
-voluntary
smooth muscle
-non striations
-involuntary
smooth muscle is found mainly in the walls of
hollow (tubelike) organs
Smooth muscle fiber characteristics
-shape
-nucleus
-surrounded
-arranged
shape- spindle-shaped
nucleus-uninucleate
surrounded- scant endomysium
arranged-two layers (circular and longitudinal)
spindle-shaped, uninucleate, and surrounded by scant endomysium and are arranged in two layers (circular and longitudinal)
smooth muscle fibers
striated, uninucleated and under involuntary control
cardiac muscle
The cardiac cells are cushioned by small amounts of endomysium and are arranged in
spiral or figure
8–shaped bundles
branching cells joined by special gap junctions called intercalated discs
cardiac muscle
Cardiac muscle fibers are branching cells joined by special gap junctions called
intercalated discs
are the structural and functional
units of skeletal muscle.
sarcomeres
precise arrangement of even smaller structures within sarcomeres– Thick and Thin Myofibrils
myofilaments
interconnecting tubules and sacs that is used for store calcium and to release it on demand when the muscle fiber is
stimulated to contract
Sarcoplasmic reticulum
Sarcoplasmic reticulum interconnecting tubules
and sacs that is used for
store calcium and release
Muscle fibers have several special functional properties (3)
Irritability
Contractility
Extensilibity
also called responsiveness, which is
the ability to receive and respond to a stimulus.
Irritability
, is the ability to forcibly shorten
when adequately stimulated.
Contractility
is the ability of muscle fibers to stretch, whereas elasticity is their ability to recoil and resume their resting length after being
stretched.
Extensibility
Skeletal muscle fibers must be stimulated by
nerve impulses
may stimulate a few muscle fibers or hundreds of them, depending on the particular muscle and the work it does.
one motor neuron
A motor unit consists of ______ and _______ it stimulates
one neuron
all the skeletal muscle fibers
contain synaptic vesicles filled with neurotransmitter which stimulates skeletal muscle fibers is Acetylcholine
or Ach.
Neuromuscular junction
Neuromuscular junctions, contain synaptic
vesicles filled with
neurotransmitter
Neuromuscular junctions, contain synaptic
vesicles filled with neurotransmitter which
stimulates skeletal muscle fibers is
Acetylcholine or Ach
states that a “muscle fiber will
contract to its fullest extent when it is stimulated adequately; it never partially contracts.
Muscle Law
Muscle Law states that a “_____ will
contract to its ______ when it is ____; it never ______.
muscle fiber
fullest extent
stimulated adequately
partially contracts
the whole muscle reacts to stimuli
with ______, or ______, which generate different amounts of
force.
graded responses
different degrees of shortening
Graded Muscle Contraction is generated by: (2)
- (1) by changing the frequency of muscle
stimulation - (2) by changing the number of muscle fibers being stimulated at one time.
Graded Muscle Contraction
- (1) by changing the _____ of muscle
stimulation - (2) by changing the number of _____ being stimulated at one time.
frequency
muscle fibers
Type of muscle contraction (2)
Isotonic Contractions
Isometric Contractions
he myofilaments are successful in their sliding movements, the muscle shortens, and movement occurs. Bending the
knee, lifting weights, and smiling are all examples of isotonic contractions.
Isotonic contractions
the myosin filaments are “spinning their wheels,” and the tension in the muscle keeps increasing. They are trying to slide,
but the muscle is pitted against some more or less immovable object.
Isometric contractions
Difference between isotonic and isometric contraction
Isotonic- muscle shortens, movement occurs
Isometric- muscle stays the same, tension increases,
he maintenance of partial contraction of a muscle, important for generating reflexes, maintaining posture and balance, and controlling proper function of other organ
systems.
muscle tone
Tone is controlled by the __________,
which measures muscle stretch.
sensory muscle spindle
_____- is controlled by the sensory muscle spindle, which measures muscle stretch.
Tone
- Tone is not limited to skeletal muscles, but is also a property of ___ and ____.
cardiac and smooth muscles
The continuous and passive partial contraction of the muscles, which helps maintain
poisture
helps us reach a steady rate of
ATP production and improves the efficiency of aerobic respiration.
aerobic respiration
exercises require very little time and
little or no special equipment
Resistance
When a muscle’s name includes the ______, its fibers or whole structure run parallel to that imaginary line.
term rectus (straight)
straight muscle of the thigh.
rectus femoris
a muscle’s name tells you that the muscle fibers run obliquely (at a slant) to the imaginary line.
oblique
Relative size of the muscle
largest-
smallest-
long-
largest- maximus
smallest- minimus
long- longus
Location of the muscle
temporalis-
frontalis-
temporalis- temporal
frontalis- frontal bones
-the muscle has its origin on the sternum (sterno)
-(cleido)
-sternocleidomastoid
-clavicle
shape of bone that is roughly triangular
deltoid muscle
action of the muscle
-muscle of the thigh
-muscle of the wrist
-adductor
-adduction
arranged in concentric rings
fascicles
Fascicles are arranged in
concentric rings
typically found surrounding
external body openings which they close by
contracting, creating a valve.
circular muscles
A general term for such muscles is s
phincters (“squeezers”).
muscle surrounding the eyes and mouth
orbicularis muscles
In a _____, the fascicles converge
toward a single insertion tendon.
convergent muscle
A convergent muscle is ____ and ____, such as the ___ ____ ____ of the anterior thorax
triangular or fan-shaped
pectoralis major muscle
the length of the fascicles
run parallel to the long axis of the muscle, as in the
sartorius of the anterior thigh.
Parallel arrangement
These muscles are straplike
Parallel arrangement
modification of the parallel arrangement that results in a spindle- shaped muscle with an expanded belly (midsection) and
tapered ends.
fusiform
Example of fusiform, a modification of the parallel arrangement
biceps brachii muscle
short fascicles attach obliquely
to a central tendon.
pennate pattern
In the extensor digitorum muscle of the leg, the fascicles insert into only one side of the tendon, and the muscle is
unipennate
If the fascicles insert into opposite sides of the tendon, the muscle is bipennate
bipennate
If the fascicles insert from several different sides, the muscle is
multipennate
Pennate Pattern: difference
Unipennate-
Bipennate-
Multipennate-
Unipennate-only side of tendon
Bipennate- opposite sides of tendon
Multipennate- sev. diff sides
- movement, generally in the sagittal plane, that decreases the angle of the joint and brings two bones closer together
Flexion
typical of hinge joints (bending the
knee or elbow), but it is also common at ball-and socket joints (for example, bending forward at the hip).
Flexion
Type of muscle movement (6)
-Flexion
-Extension
-Rotation
-Abduction
-Adduction
-Circumduction
opposite of flexion, so it is a
movement that increases the angle, or distance,
between two bones or parts of the body
(straightening the knee or elbow).
extension
greater than 180° (as when you
move your arm posteriorly beyond its normal
anatomical position, or tip your head
extension
movement of a bone around
longitudinal axis its
rotation
common movement of ball-and
socket joints and describes the movement of the
atlas around the dens of the axis.
rotation
is moving a limb away (generally in
the frontal plane) from the midline, or median
plane, of the.
abduction
fanning movement of your fingers or toes when they are spread apart
abduction
as “adding” a body part by bringing it closer to the trunk.
adduction
combination of flexion, extension, abduction, and adduction commonly seen in ball-and-socket joints, such as the
shoulder.
circumduction
The proximal end of the limb is stationary, and its
distal end moves in a circle.
Circumduction
Muscle Movement: Special Movement (7)
-Dorsiflexion
- Plantar Flexion
- Inversion
-Eversion
-Supination
-Pronation
-Opposition
Up-and-down movements of the foot at the
ankle are given special names.
Dorsiflexion and Plantar Flexion
Lifting the foot so that its superior surface
approaches the shin (pointing your toe toward your head) is
dorsiflexion
pointing the toes away from your head is
plantar flexion
Dorsiflexion of the foot corresponds to ____ and ______ of the hand at the wrist
extension
hyperextension
plantar flexion of the foot corresponds to
____ of the hand
flexion
also special movements of the foot
inversion and eversion
turn the sole medially, as if you
were looking at the bottom of your foot.
inversion
the foot, turn the sole laterally
eversion
“turning backward”
supination
“turning forward”
pronation
occurs when the forearm rotates laterally so that the palm faces anteriorly (or up) and the radius and ulna are parallel, as in anatomical position.
Supination
occurs when the forearm rotates medially so that the palm faces posteriorly (or down). Pronation brings the radius across the ulna so that the two bones form an X.
Pronation
This is the action by which you move your thumb to touch the tips of the other fingers on the same hand.
opposition
- In the palm of the hand, the ____between ____ and the ______ allows opposition of the thumb
saddle joint
metacarpal 1
carpals
This unique action makes the human hand a fine tool for grasping and manipulating objects.
opposition
Muscles can’t ___—they can only pull as they ___
push
contract
Muscles are arranged so that whatever one
muscle (or group of muscles) can do, other
muscles can ____
reverse
muscle that has the major
responsibility for causing a particular movement
primer mover
Muscles that oppose or reverse a movement
antagonist muscle
help prime movers by producing the
same movement or by reducing undesirable movements.
synergist
are specialized synergists. They hold a
bone still or stabilize the origin of a prime mover so all the tension can be used to move the insertion bone.
fixators
