The Muscular System

Function of the muscular system

• Provides movement in conjunction with the skeletal system

• Important in life support

• Used by humans and other animals for food

Classifications of Muscles

• Voluntary: Movement of the muscle is under the control of the animal

• Involuntary: Movement of the muscle is not controlled by the animal

Types of Muscles

• Smooth Muscles: Involuntary muscles, found in the walls of internal organs and the blood vessels.

Smooth Muscles

• Are not under voluntary control

• Are spindle shaped and are not striated.

• Interlace to form Sheets of smooth muscle tissue.

• Are found in many internal organs: Stomach, Intestines, Blood Vessel walls

Types of Muscles• Cardiac

Muscles: Muscles that form a network to make up the heart. Not under control of the brain, but under their own control

Cardiac Muscles

• Only found in the Heart

• Are Striated

• Are NOT under Voluntary Control

• Contract Without Direct stimulation by the Nervous System

Types of Muscles

• Skeletal Muscles: Have a striped appearance, include voluntary and involuntary, attached to and moves your bones. This is a majority of the muscle tissue in your body.

Skeletal Muscles

• Are made of Elongated Cells called MUSCLE FIBERS

• Are grouped into dense bundles called FASCICLES

• Are LARGE and have MORE than ONE NUCLEUS

• Most are Voluntary

Muscles of the Front Limb

• The largest and most important muscle in animals attaching the front legs to the body is the serratus ventralis. It is fan shaped and supports the trunk of the body between the legs.

Muscles of the Front Limb and Shoulder

• The rotator cuff tendons attach to the deep rotator cuff muscles. This group of muscles lies just outside the shoulder joint. These muscles help raise the arm from the side and rotate the shoulder in the many directions. They are involved in many day-to-day activities.

Muscles of the Front Limb and Shoulder

• The large deltoid muscle is the outer layer of shoulder muscle. The deltoid is the largest, strongest muscle of the shoulder. The deltoid muscle takes over lifting the arm once the arm is away from the side.

Muscles of the Upper Arm

• The bicep brachii muscle is located in the upper arm. The primary function of the bicep muscle is elbow flexion, or the movement of the forearm towards the shoulder. This muscle is also used for turning the hand from a palms down position to palms up position.

Muscles of the Lower (Fore) Arm

• The muscles of the lower arm, or forearm are used to flex or move the hand, wrist and fingers.

• Brachioradialis is only one of the almost 30 muscles. It flexes the forearm at the elbow

Muscles of Back Limbs or Legs

Muscles of the Muscles of the Back Limb (Hip and Thigh)

• The hip is surrounded by thick muscles.

• The gluteals make up the muscles of the buttocks on the back of the hip.

Muscles of the Muscles of the Back Limb (Hip and Thigh)

The inner thigh is formed by the adductor muscles. The main action of the adductors is to pull the leg inward toward the other leg.

Muscles of the Muscles of the Back Limb (Hip and Thigh)

The muscles that flex the hip are in front of the hip joint. These include the iliopsoas muscle.

This deep muscle begins in the low back and pelvis and connects on the inside edge of the upper femur

Muscles of the Muscles of the Back Limb (Hip and Thigh)

• Another large hip flexor is the rectus femoris. The rectus femoris is one of the quadriceps muscles, the largest group of muscles on the front of the thigh.

Muscles of the Back Limb• The primary

movements are extension and flexion.

• The main extensor muscle of the hip is the Hamstring.

• The Hamstrings are the group of muscles that are positioned at the back of our thighs.

Muscles of the Upper Leg• The

Quadriceps are the extender muscles on the front side of the thigh. Their main function is to extend the knee.

Anterior Posterior

The Hamstrings are the muscles on the back side of the upper leg. Their function is to bend the leg.

Muscles of the Upper Leg

Muscles of the Lower Leg

• The Gastrocnemius is the calf muscle that is visible from the outside of the body.

• It attaches to the heel with the Achilles Tendon and originates behind the knee on the femur, crossing two joints.

Muscles of the Lower Leg

• The function of the Gastrocnemius is to elevate the heel (known as plantar flexion).

• The function of the Soleus is exactly the same as the Gastrocnemius: to raise the heel. The only difference is that it works in a different position: with the knee bent.

Muscles of the Trunk, Headand Neck

• Many of the muscles originate from the vertebrae

Muscles of the Trunk, Headand Neck

• There is greater flexibility in the neck than in the spinal column because of the muscles within

The Complex System that is responsible for movement and protection of internal organs