4 Muscular System Flashcards
Muscle Function
- Produce Movement
- Maintain Posture and Body Position
- Stabilize joints
- Generate heat
- additional functions
Skeletal muscle fibers are packaged into organs called _ that attach to the skeleton
skeletal muscles
Skeletal Muscle cover our _ , they help form the smooth contours of the body.
bone and cartilage framework
physical structure of
Skeletal muscle fibers
- large
- cigarshaped
- multinucleate cells
Skeletal muscle is also known as _ and as
voluntary muscle
striated muscle
Connective Tissues wrapping
wraps entire muscle
epimysium
Connective Tissues wrapping the Muscle Fibers
wrapped in endomysium
muscle fiber
Connective Tissues wrapping the Muscle Fibers
wrapped in perimysium
fascicle
no striations and is
involuntary
smooth muscle
found mainly in the walls of
hollow (tubelike) organs
smooth muscle
- are spindle-shaped, uninucleate, and surrounded by scant endomysium and are arranged in two layers (circular and longitudinal)
- single, fusiform, no striations
smooth muscle
- is striated, uninucleated and under involuntary control
- branching chains of cells
Cardiac Muscle
are cushioned by small amounts of endomysium and are arranged in spiral or figure 8–shaped bundles
cardiac cell
Cardiac muscle fibers are branching cells joined by special gap junctions called _
intercalated discs
connective tissue components of skeletal muscle
- epimysium
- perimysium
- endomysium
connective tissue components of cardiac muscle
endomysium attached to the fibrous skeleton of the heart
connective tissue components of smooth muscle
endomysium
regulation of contraction of skeletal muscle
voluntary via nervous system controls
regulation of contraction of cardiac muscle
- involuntary
- internal heart pacemaker
- nervous system controls
- hormones
regulation of contraction of smooth muscle
- involuntary
- nervous system controls
- hormones
- chemicals
- stretch
speed of contraction of skeletal muscle
slow to fast
speed of contraction of cardiac muscle
slow
speed of contraction of smooth muscle
very slow
rhythmic contraction of skeletal muscle
no
rhythmic contraction of cardiac muscle
yes
rhythmic contraction of smooth muscle
yes, in some
Microscopic Anatomy of Muscle
- sarcomeres
- myofilaments
- sarcoplasmic reticulum
Microscopic Anatomy of Muscle
structural and functional units of skeletal muscle
sarcomeres
Microscopic Anatomy of Muscle
are the precise arrangements of even smaller structures within sarcomeres - thin and thick myofibrils
myofilaments
Microscopic Anatomy of Muscle
interconnecting tubules and sacs that is used to store calcium and to release it on demand when the muscle fiber is stimulated to contract
sarcoplasmic reticulum
Special functional properties of muscle fibers
- irritability
- contractility
- extensibility
Skeletal Muscle Fiber Activity
- aka responsiveness
- ability to receive and respond to stimulus
irritability
Skeletal Muscle Fiber Activity
the ability to forcibly shorten when adequately stimulated
contractility
Skeletal Muscle Fiber Activity
the ability of muscle fibers to stretch, whereas elasticity is their ability to recoil and resume their resting length after being stretched
extensibility
Muscle Contraction
Skeletal muscle fibers must be stimulated by _
nerve impulses
Muscle Contraction
- _ may stimulate a few muscle fibers or hundreds of them, depending on the particular muscle and the work it does
- A _ consists of one neuron and all the skeletal
muscle fibers it stimulates
- One motor neuron (nerve cell)
- motor unit
Muscle Contraction
Neuromuscular junctions, contain synaptic vesicles filled with neurotransmitter which stimulates skeletal muscle fibers is _.
Acetylcholine or Ach
Contraction of Muscle as Whole
Muscle law states that:
a “muscle fiber will contract
to its fullest extent when it is stimulated adequately;
it _”
never partially contracts
However, the whole muscle reacts to stimuli with graded responses, or different degrees of shortening, which generate different amounts of force
Graded Muscle Contraction is generated by:
- by changing the frequency of muscle stimulation
- by changing the number of muscle fibers being stimulated at one time.
What Fueled Muscle Contraction?
- direct phosphorylation (creatine phosphate CP and ADP)
- aerobic pathway (glucose)
- anaerobic pathway (glycolysis and lactic acid formation)
Types of Muscle
Contraction
- isotonic contractions
- isometric contractions
types of muscle contraction
the myofilaments are successful in their sliding movements, the muscle shortens, and movement
occurs.
isotonic contractions
types of muscle contraction
examples of isotonic contractions.
- Bending the knee
- lifting weights
- smiling
types of muscle contraction
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
types of muscle contractions
example of isometric contractions
- when you push the palms of your hands together in front of you, your arms and chest muscles are contracting isometrically.
the 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
controlled by the sensory muscle spindle,
which measures muscle stretch
Tone
applicable to skeletal, cardiac, smooth muscles
The continuous and passive partial contraction of the muscles, which helps maintain _
posture
Effects of Exercise
results in stronger,
more flexible muscles with greater resistance to fatigue
Aerobic exercise, or endurance exercise
- because the blood supply to the muscles increases, and the individual muscle fibers form more mitochondria and store more oxygen.\
- Aerobic exercise helps us reach a steady rate of ATP production and improves the efficiency of aerobic respiration
Effects of Exercise
require very little time and little or no
special equipment
Resistance exercises
- The increased muscle size and strength that result are due mainly to enlargement of individual muscle fibers (they make more contractile myofilaments) rather than to an
increase in their number. - The amount of connective tissue that reinforces the muscle also increases
Direction of the muscle fibers.
oblique in a muscle’s name tells you that the muscle fibers run obliquely (_ ) to the imaginary line
at a slant
Direction of the muscle fibers.
the _ is the
straight muscle of the thigh.
rectus femoris
Direction of the muscle fibers.
When a muscle’s name includes the term _ , its fibers or whole structure run parallel to that imaginary line.
rectus (straight)
Direction of the muscle fibers.
Some muscles are named in reference to some _ , usually the midline of the body or the long axis of a limb bone.
imaginary line
largest muscle of the
gluteus muscle group
gluteus maximus
name of muscle
- largest
- smallest
- long
- maximus
- minimus
- longus
based on the bone
muscle on:
1. temporal bones
2. frontal bones
- temporalis
- frontalis
muscle name
based on number of origins
- biceps = 2
- triceps = 3
- quadriceps = 4
muscle name after their attachment sites
- on sternum and clavicle, and inserts on the mastoid process of the temporal bone
sternocleidomastoid
sternum - sterno
clavicle - cleido
named based on shape of muscle
triangular muscle on shoulder
deltoid
Greek letter delta (Δ)
named based on action of muscle
- adduction of thigh
- extends muscles of the wrist
- adductor
- extensor
Muscles
4 Arrangement of the
Fascicles
- Circular pattern
- Convergent Muscle
- Parallel Arrangement
- Pennate Pattern
Arrangement of the Fascicles
- Fascicles are arranged in concentric rings
- typically found surrounding external body openings which they close by contracting, creating a valve (sphincters = squeezers)
- ex: orbicularis muscles around eyes and mouth
circular pattern
Arrangement of the Fascicles
- the fascicles converge toward a single insertion tendon
- is triangular or fan-shaped,
- ex: the pectoralis major muscle of the anterior thorax
convergent muscle
Arrangement of the Fascicles
- the length of the fascicles run parallel to the long axis of the muscle, as in the sartorius of the anterior thigh.
- These muscles are straplike
- its fusiform modification results in a spindle- shaped muscle with an expanded belly (midsection) and tapered ends
- ex: biceps brachii muscle of the arm
parallel arrangement
Arrangement of the Fascicles
short fascicles attach obliquely to a central tendon. In the extensor digitorum muscle of the leg
pennate pattern
Arrangement of the Fascicles
If the fascicles insert from several different sides, the muscle is _
multipennate
Arrangement of the Fascicles
If the fascicles insert into opposite sides of the tendon, the muscle is _
bipennate
Arrangement of the Fascicles
the fascicles insert into only one side of the tendon, and the
muscle is _
unipennate
Types of Muscle
Movement
- flexion
- extension
- rotation
- abduction
- adduction
- circumduction
Special Movements
- dorsiflexion and plantar flexion
- inversion and eversion
- supination and pronation
- opposition
Types of Muscle Movement
- generally in the sagittal plane
- decreases the angle of the joint
- brings two bones closer together
- typical of hinge joints (bending the knee or elbow),
- also common at ball-and-socket joints (for example, bending forward at the hip)
flexion
Types of Muscle Movement
- movement that increases the angle, or distance, between two bones or parts of the body (straightening the knee or elbow).
- greater than 180° (as when you move your arm posteriorly beyond its normal anatomical position, or tip your head
extension
Types of Muscle Movement
- movement of a bone around its longitudinal axis
- common
movement of ball-andsocket joints and describes the movement of the atlas around the dens of the axis
rotation
Types of Muscle Movement
- moving a limb away (generally in the frontal plane) from the midline, or median plane
- fanning movement of your fingers or toes when they are
spread apart
abduction
Types of Muscle Movement
- it is the movement of a limb toward the body midline
- as
“adding” a body part by bringing it closer to the trunk
adduction
Types of Muscle Movement
- is a combination of flexion,
extension, abduction, and adduction commonly seen in ball-and-socket joints, such as the shoulder. - proximal end of the limb is stationary, and its distal end moves in a circle
circumduction
Special Movement
- Up-and-down movements of the foot at the ankle are given special names
* Lifting the foot so that its superior surface approaches the shin (pointing your toe toward your head)
* pointing the toes away from your head is
- Dorsiflexion and plantar flexion
* Dorsiflexion
* plantar flexion
Special Movement
- Dorsiflexion of the foot corresponds to _ and _ of the hand at the wrist,
- whereas plantar flexion of the foot corresponds to _ of the hand.
extension and hyperextension
flexion
Special Movement
- are also special movements of the foot
- To _ the foot, turn the
sole medially, as if you were looking at the bottom of your foot. - To _ the foot, turn the sole
laterally.
invert/ inversion
evert/ eversion
Special Movement
movement of the radius around ulna:
* turning backward
* turning forward
- supination (forearms rotates laterally, palm faces anteriorly)
- pronation (forearm rotates medially, palm faces posteriorly)
Special Movement
- In the palm of the hand, the saddle joint between metacarpal 1 and the carpals allows _ of the thumb
- thumb touches other fingers of the same hands
- makes human hand a fine tool for grasping and manipulating objects
opposition
Interactions of Skeletal Muscles in the Body
In general, groups of muscles that produce opposite
movements lie on _ of a joint.
opposite sides
Interactions of Skeletal Muscles in the Body
Muscles are arranged so that whatever one muscle (or
group of muscles) can do, other muscles can _
reverse
Interactions of Skeletal Muscles in the Body
Muscles can’t _ —they can only _ as they contract— so
most often body movements result from two or more
muscles acting together or against each other.
push
pull
Interactions of Skeletal Muscles in the Body
- prime mover
- antagonist muscle
- synergist
- fixators
Interactions of Skeletal Muscles in the Body
- 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
Interactions of Skeletal Muscles in the Body
help prime movers by producing the same movement or by reducing undesirable movements.
Synergist
Interactions of Skeletal Muscles in the Body
Muscles that oppose or reverse a movement
Antagonist Muscle
Interactions of Skeletal Muscles in the Body
muscle that has the major responsibility for causing a particular movement
Prime Mover
