The three types of muscle tissue are
Skeletal, cardio, and smooth
Describe the difference between a tendon and an aponeurosis.
Aponeurosis are broad fibrous sheets which may attach to bone or to the coverings of adjacent muscles. Tendons are cord-like and attach muscle to bone.
Describe how connective tissue associates with skeletal muscle.
Fascia blends with the epimysium, a layer of connective tissue that closely surrounds each skeletal muscle. Other layers of connective tissue, called
perimysium, extend inward from the epimysium and
separate the muscle tissue into small sections. Each mus
List the major parts of a skeletal muscle fiber, and describe the function of each part.
A muscle fiber is a single, multinucleated cell, which contracts when stimulated. It is a thick, elongated cylinder with rounded ends that may extend the entire length of the muscle. Its component parts are:
a. Sarcolemma�the specific name for a muscle fi
Describe a neuromuscular junction.
Each skeletal muscle fiber is connected to a fiber from a nerve cell called a motor neuron. The muscle fiber contracts only when stimulated by this specific fiber. At the connection point between the nerve fiber and the muscle fiber, the muscle fiber's sa
A neurotransmitter:
a. binds actin filaments, causing them to slide
b. diffuses across a synapse from a neuron to a muscle cell
c. carries ATP across a synapse
d. travels across a synapse from a muscle cell to a neuron
b. diffuses across a synaptic cleft from a neuron to muscle cell
List the major events of muscle fiber contraction and relaxation.
Muscle fiber contraction is a complex process involving a number of cell parts and chemical substances that result in the sliding movement of the actin and myosin filaments and causes a contraction. A myosin filament is composed of protein strands with gl
Describe how ATP and creatine phosphate interact.
The basic energy source for muscle contraction comes from ATP molecules supplied by the mitochondria. The cross-bridges of myosin contain the enzyme ATPase that causes ATP to decompose into ADP and phosphate, thereby releasing energy. The primary source o
Describe how muscles obtain oxygen.
Oxygen is carried from the lungs by hemoglobin in the blood. When the hemoglobin reaches the muscle, the oxygen is transferred to the myoglobin in the muscle fiber. Myoglobin is similar to hemoglobin in its oxygen capacity, and reduces the muscle's need f
Describe how an oxygen debt may develop.
When skeletal muscles have been used where they have exceeded their oxygen reserves, anaerobic respiration must take over. Anaerobic respiration changes glucose into pyruvic acid, and due to the lack of oxygen, the pyruvic acid is converted into lactic ac
Explain how muscles may become fatigued.
If a muscle is exercised strenuously for a long period, it may lose its ability to contract. This is called muscle fatigue. This condition may result from an interruption in a muscle's blood supply or from the depletion of acetylcholine in the motor nerve
Explain how skeletal muscle function affects the maintenance of body temperature.
Two-thirds of the energy released in cellular respiration is lost as heat. Muscle accounts for most of the total body mass so when muscles are active, large amounts of heat are produced. This is circulated throughout the body by the blood thereby supporti
Define threshold stimulus.
A muscle fiber remains unresponsive until a certain amount of stimulus is applied. This minimal strength required is called the threshold stimulus.
Define motor unit.
The nerve fibers of a motor neuron are highly branched. Each of these branches is connected to the motor end plate of a single muscle fiber. When the motor neuron is stimulated, the impulse is carried to all of the muscle fibers attached to its branches.
Which of the following describes the addition of muscle fibers to take part in a contraction?
a. summation
b. recruitment
c. tetany
d. twitch
b. recruitment
Explain how skeletal muscle stimulation produces a sustained contraction.
If a muscle is exposed to a series of stimuli increasing in frequency, a point is reached where the muscle is unable to complete its relaxation period before the next stimulus arrives. This stacking of twitches causes a sustained contraction.
Distinguish between tetanic contraction and muscle tone.
A tetanic contraction (tetany) results when a sustained forceful contraction lacks even partial relaxation.
Muscle tone (tonus) is a response to nerve impulses originating repeatedly from the spinal cord, and traveling to small numbers of muscle fibers wi
Distinguish between multiunit and visceral smooth muscle fibers.
Multiunit smooth muscle features fibers that are somewhat disorganized and occur as separate fibers rather than in sheets. It can be found in the iris of the eyes and in the walls of blood vessels. Multiunit smooth muscle tissue contracts only after stimu
Compare smooth and skeletal muscle contractions.
Both smooth and skeletal muscle contractions involve the reactions of actin and myosin, are triggered by membrane impulses and the release of calcium ions, and use energy from ATP molecules. The differences between their contractions are:
a. Skeletal musc
compare contraction mechanisms of cardiac and skeletal muscle fibers.
Skeletal muscle can contract individually. Cardiac muscle works in a network. When one portion of the cardiac muscle network is stimulated, the impulse travels to the other fibers in the network. It then contracts as a unit. It is self-exciting and rhythm
Distinguish between a muscle's origin and its insertion.
The origin of a muscle is the end of the muscle attached to an immovable part. The insertion is the end of a muscle attached to a moveable part. When a muscle contracts, the insertion is pulled toward the origin.
Define agonist, antagonist, and synergist.
The prime mover is the muscle that is primarily responsible for a certain movement. An agonist is synonymous with prime mover. A synergist is a muscle that aids the prime mover in its action to move a part. An antagonist is a muscle that acts against the
buccinator
compresses the cheeks
epicranius
consists of two parts�the frontalis and the occipitalis
orbicularis oris
closes lips
platysma
extends over the neck from the chest to the face
rhomboid major
can raise and adduct the scapula
splenius capitis
can pull the head into an upright position
temporalis
inserted on the coronoid process of the mandible
zygomaticus
draws the corner of the mouth upward
biceps brachii
strongest supinator of the forearm
brachialis
strongest flexor of the elbow
deltoid
abducts the arm
latissimus dorsi
pulls the shoulder back and downward
pectoralis major
pulls the arm forward and across the chest
pronator teres
rotates the arm medially
teres minor
rotates the arm laterally
triceps brachii
primary extensor of the elbow
biceps femoris
a hamstring muscle
external oblique
compresses the contents of the abdominal cavity
gastrocnemius
a plantar flexor of the foot
gluteus maximus
largest muscle in the body
gluteus medius
abducts the thigh
gracilis
adducts the thigh
rectus femoris
a member of the quadriceps group
tibialis anterior
inverts the foot