Muscular System

Whitley Jones

Tiffany Webb

8 Oct. 2007

What Is the Muscular System?

• The main job of the muscular system is to provide movement for the body.

• The Muscular system consists of 3 different types of muscle tissue: skeletal, cardiac, and smooth.

Cardiac Muscles

• Found in the heart

• Striated • Involuntary

Skeletal Muscle• It has stripe-like markings, or

striations. The skeletal muscles is composed of long muscle fibers.

• The nervous system controls the contraction of the muscle. Many of the skeletal muscle contractions are automatic. However we still can control the action of the skeletal muscle.

• And it is because of this reason that the skeletal muscle is also called voluntary muscle

Smooth Muscles

• Much of our internal organs is made up of smooth muscles.

• They are found in the urinary bladder, gallbladder, arteries, and veins. Also the digestive tract is made up of smooth muscle as well.

• The smooth muscles are controlled by the nervous system and hormones.

• Also called involuntary muscles

Voluntary and Involuntary Muscles

• There are two types of muscles in the system and they are the involuntary muscles, and the voluntary muscles.

• Voluntary muscles-muscles we can control • Involuntary muscles-muscles we can’t control

• The heart, or the cardiac muscle, is an example of involuntary muscle.

How the Muscle Works in the Heart

• Heart muscle serves as a “pump” for the heart, pumping blood into the blood vessels and all the tissues in the body.

Naming of Muscles

• Skeletal muscles are named according to a number of criteria, each of which describes a muscle in some way.

1.Location of the muscle

• Some muscle names indicate the bone or body region with which the muscle is associated.

• For example, the temporalis muscle overlies the temporal bone and intercostal (costal=rib) muscles runs between the ribs.

2.Shape of the Muscle

• Some muscles are named for their distinctive shapes.

• Example= the deltoid muscle is triangular, (deltoid=triangular) and together the right and left trapezius muscles form a trapezoid.

3. Relative size of the muscle

• Terms such as maximus (largest), minimus (smallest), longus (long), and brevis (short) are often used in muscle names- gluteus maximus and gluteus minimus (the large and small gluteus muscles)

4. Number of origins

• When biceps, triceps, or quadriceps forms part of a muscles name, you can assume that the muscle has two, three or four origins.

• For example, the biceps brachii muscle of the arm has two origins or heads.

5. Location of attachments

• Some muscles are named according to their points of origin and insertion. The origin is always named first.

• Example, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido) and it inserts on the mastoid process of the temporal bone

5 Golden Rules of Muscle Movement

• 1. All muscles cross at least one joint

• 2. Typically, the bulk of the muscle lies proximal to the joint crossed

• 3. All muscles have at least two attachments: the origin and the insertion

• 4. Muscles can only pull, they never push.

• 5. During contraction, the muscle insertion moves toward the origin

6. Action

• When muscles are names for their action, action words such as flexor, extensor, and adductor appear in the muscle’s name.

• For example, the adductor longus, located on the medial thigh, brings about thigh adduction, and the supinator muscle supinates the forearm

Flexor Muscles

• Flexors bend at the joint, decreasing the interior angle of the joint. The «bracius» humorous, or bicep, is a flexor of the elbow joint, bringing the fist towards the shoulder. If a flexor appears in either the wrist or ankle joints, it becomes a plantar flexor

Extension

• Opposites of flexors, extensors unbend at the joint, increasing the interior angle «graphic here, possibly the same as that above». The «tracius» humorous, or tricep, is an extensor of the elbow joint, taking the fist farther away from the shoulder. If an extensor is found in the wrist or ankle joints, it becomes a dorsiflexor.

Abduction

• Abductors take away from the body, like lifting the arm to the side. Abd- means to take away, like abduct and abdicate. Spreading out your fingers uses abductors, because you are taking away your fingers from an imaginary line running down your arm.

Adduction

• Adductors, the opposites of abductors, move toward the body. Add- means to increase or include. By lowing an arm raised to the side, or moving your fingers together while keeping them straight, your muscles are adducting.

Rotation

• Movement of a bone around it’s longitudinal axis.

• Common in ball-and-socket joints (ex. Shoulders)

Ex. Shaking your head “no”

Circumduction

• Combination of flexion, extension, abduction, and adduction.

• Also seen is ball and socket joints such as the shoulder

Pronation

• Movement of the palm of the hand from an anterior, upward facing, position to a posterior, downward facing position

Supination

• Movement of the palm from an downward position to an upward position.

• Opposite of pronation

Inversion

• Turning the sole if the foot so that it faces medially

Eversion

• Turning the sole of the foot laterally

• Opposite of inversion

Dorsiflexion

• The movement at the ankle that moves instep of the foot up and dorsally toward the shin (standing on your heels)

Plantar Flexion

• Movement that straightens the ankle joint, causing the toes to point downward (standing on your toes)

Prime mover

• When several muscles are contracting at the same time, the muscle that has the major responsibility for causing a particular movement

Antagonists

• Muscles that oppose or reverse a movement

• Antagonists can become prime movers

• Ex. Biceps of the arm (prime mover of the elbow flexion) is antagonized by the triceps (a prime mover of elbow extension)

Synergists

• Syn= together, erg= work • muscles the help prime movers by producing

the same movement or by reducing undesirable or unnecessary movement.

• For example, the finger-flexor muscles cross both at the wrist and the finger joints. You can make a fist without bending your wrist because the synergist muscles stabilize the wrist joints and allow the prime mover to act on the finger joints

Fixators

• Specialized synergists. They act to hold a bone still or stabilize the origin of a prime mover so all the tension can be used to move the insertion bone.

• The postural muscles that stabilize the vertebral column are fixators, as are the muscles that anchor the scapula to the thorax

Major Skeletal Muscles

• The muscular body is divide into ten different areas where muscles can be found: facial, neck, shoulder, arm, forearm, thorax, abdomen, hip, pelvis/thigh, leg

Facial

• In the facial are one finds all the muscles which move the face. Orbicularis oculi-sound are the two muscles that move the eye are. Frontalis-sound and Temporalis-sound are the two muscles which move the forehead and sides of your head. Zygomaticus-sound ands Masseter-sound are the two muscle that work in conjunction to move the jaw and upper lip area. Orbicularis oris-sound is the muscle which moves your lips.

Neck• The neck area is almost entirely

moved by the sternohyoid-sound and Sternocleidomastoid-sound. These muscles allow the neck to move your head left and right. They work with the platysma muscle to control how far you can move your head left and right. What allows your head to move up and down is the trapezius-sound. The trapezius is so large that it extend down to the shoulder and thorax area. The trapezius is a good example of how some muscles are named by their shape. the trapezius looks just like a trapezoid.

Shoulder

• A group of muscles all work together to move the whole shoulder area. This group takes into account the trapezius-sound, deltoid-sound, infraspinatus-sound, teres major-sound, and the rhomboid major-sound. The rhomboid major is called so because its shaped like the geometric shape of a rhombus. Along with the help of the ball and socket joint-hyperlink in your shoulder, these group of muscles allow your arm to throw a softball, pick things over your head, and give your arms a good stretch early in the morning.

Arm

• Most known amongst teenage weight lifters is the arm area. The famous bicep brachii-sound is the muscle that allows you to bring your forearm close to your body and form a huge ball of muscle which catches a lot of attention amongst weight lifters. The tricep brachii-sound and brachialis-sound are the two other muscles located in the arm region. These muscles allow a person to do push-ups!

Forearm

• A majority of the muscle in the forearm help control a part of the arm. Amongst these is the Brachiodialis major-sound, palmaris longus-sound, and Flexor carpi radialis-sound. The name of the flexor carpi radialis is a good example of how muscles are named by their function and location. This muscle is named carpi because of the bones that it helps move, the carples. Also, the name of radialis is made by the bone that its attached to, the radius.

Thorax

• The thorax is the set of muscles which carrying your head, arms, stomach, and any other upper body areas. These muscles are the trapezius-sound and latissimus dorsi-sound. Usually, the majority of the muscles of the thorax can be damaged easily if one does not stretch before exercise, or lifts a heavy load.

Abdomen

• The abdominal area consists of the muscles that allows you to bend down and move your waist from side to side. The internal oblique-sound and external oblique-sound are the muscles that move your body from left to right. The Transverses abdominus-sound and Rectus abdominus-sound, along with the trapezius-sound an latissimus dorsi-sound allow you to bend down and grab objects.

Hip

• Only two muscles make up the hip area. These are the gluteus medius-sound and gluteus maximus-sound. Probably the laziest muscles in the whole system the gluteus set of muscles are used only to sit down on.

Pelvis/Thigh

• An overlapping of muscles is what makes this area so firm. The pelvis area is usually referred to as the upper part of the leg. Muscles like the pectineus-sound and illiopsoas-sound , which help support the upper leg area are known as pelvic muscles. Thigh muscles are very rich in capillaries and support the whole body. The upper thigh muscles are abductor longus-sound, Gracilis-sound, Sartorius-sound, and Tensor fasciae latea. The lower thigh muscles are rectus femoris-sound, vastus lateralis-sound and medialis-sound. Located in the back of your leg are the hamstrings-sound. These muscles help you run, jump, and walk

Leg

• Helping the thigh region support the body is the Leg region. These muscles like the Gastrocnemius-sound, soleus-sound, porenius longus-sound, and Tibialis anterior-sound absorb the impact when one walks and runs. they also give better coordination for moving. the thigh region trust the body forward while the leg region coordinates where it should be thrusted and where it should stand.