Skeletal and Muscular System

Functions of the Bone •1. Support: it forms the internal framework •2. Protection: bones protect soft body organs. •3. Movement: muscles attached to the bone to

move the body and its part. •4. Storage: fat is stored in the internal cavities of

bones. Bone it self-serves as a storehouse of minerals. The most important being calcium and phosphors.

•5. Blood cell formation: it occurs with in the marrow cavities of certain bones.

Functions of the Muscles

• The function of most muscles is to produce movements of body parts.

• A few muscles function mainly to stabilize bones.

• Muscles of the Head That Produce Facial Expressions.

Functions of the Joints

• Direct connect joints--Connected bone and bone.

• Indirect connect(articulation)—perform movement

Joints– Bones connected

• Direct connect 1. fibrous joint

Spine of vertebra, head

2. cartilaginous joint Cartilago costalis, Vertebrae

3. Synostosis—Hip bone, sacrum

• Indirect connect(articulation) ---Joints on the limbs

structure of Articulation

1. Articular surface--articular cartilage 2. Articular capsule

1. Fibrous membrane 2. Synovial membrane– produce synovial fluid

3. Articular cavity

The Muscles

肌外膜 肌内膜 肌束

肌束膜

Muscles contracting – relaxing

Muscles contracting – relaxing and Joint movement

The Muscles

• Origin: – One end of the muscle is attached by a tendon to a

bone that remains relatively stable, usually closer to the midline of the body.

• Insertion: – The tendon on the other end of the muscle is

attached to the bone moved by the muscle.

TYPES OF MOVEMENTS AT SYNOVIAL JOINTS

• •Flexion弯曲 • •Extension伸展 • •Hyperextension过度伸展 • •lateral flexion侧屈 • •Abduction外展 • •Adduction内收 • •Circumduction环行（运动）

Flexion弯曲

• Flexion is a bending movement around a joint in a limb (as the knee or elbow) that decreases the angle between the bones of the limb at the joint.

Extension伸展

• Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts.

Hyperextension过度伸展

• Hyperextension is the joint movement extension of a body part to a maximum level or past the position of normal extension.

lateral flexion侧屈

• Lateral flexion describes the active or passive bending movement of a body part in the lateral direction, that is to say sidewards.

Abduction外展

• Abduction is movement away from the mid-line of the body.

Adduction内收

• Adduction is the movement of a body part toward the body's midline.

•Circumduction环行（运动）

• Circumduction is a conical 圆锥形的movement of a limb extending from the joint (e.g. shoulder or hip) at which the movement is controlled.

• True circumduction allows for 360 degrees of movement.

Muscles move the eyeballs •Muscles that move the eyeballs are called extrinsic

eye muscles because they originate outside the eyeballs (in the orbit) and insert on the outer surface of the sclera (“white of the eye”). The extrinsic eye muscles are some of the fastest contracting and most precisely controlled skeletal muscles in the body.

• •Three pairs of extrinsic eye muscles control movements of the eyeballs:

• •(1) superior and inferior recti (上、下直肌)

• •(2) lateral and medial recti (外、内直肌)

• •(3) superior and inferior obliques. (上、下斜肌)

Muscles move the eyeballs