Musculo skeletal system
It consists of
Bone tissue is a hard tissue, a type of dense connective tissue. Bone tissue is made up of different type of bone cells.
Osteocytes are the building blocks of the bone and form the inner matrix of bone tissue that gives strength to bones.
Osteoclasts maintain the integrity and strength of the bones.
Osteoblasts build new bones by producing collagen and minerals so that the osteocyte can remain in good functioning condition.
Stem cells form in the inner surface of the bone will later transform into osteoblasts.
Lining cells protect the bones and they also release calcium into the blood when the blood calcium levels are low.
1. Long bones: Present in the arms and legs. They act as levers to move parts
2. Flat bones: These includes the ribs, scapulae, sternum, and bones of the cranium
3. Irregular bones: These bones are seen in face and spine bones.
4. Short bones: These bones are seen in wrist and ankle bones.
5. Cortical bone: the stronger bone that is needed for support and movement.
6. Axial bones: Found in the skull, the ribs and the spinal column
7. Appendicular bones: found in the arms,legs, shoulders and the pelvis.
8. Cancellous bone or spongy bone: not as strong as cortical bone.
9. Seasmaoid bones: embedded in tendons eg. Patella.
The skeleton is compossed of 206 separate bones in an adult. The cartilages and ligaments helps to unite the bones at the joint
The skull is a body structure that forms the head. It supports the structure of the face and provides a protective cavity of the face.
The skull consists of two parts
· The cranium, which is like a box in which the brain is well protected
· The bones of the face
The cranium (skull) is the skeletal structure of the head that supports the face and protects the brain. It is subdivided into the facial bones and the brain case, or cranial vault. The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws. The rounded brain cases surrounds and protects the brain and house the middle and inner ear structures.
In the adult, the skull consists of 22 individual bones, 21 of which are immobile and united into a single unit. The 22nd bone is the mandible (lower jaw), which is the only moveable bone of the skull.
The Cranium is made up of eight bones as follows:
The face has the following 14 bones
The vertebral coloum, also known as the back bone or spine, is part of the axial skeleton. It separated by intervertebral disc.
Spine or Vertebral column is the central part of the skeleton. It supports the head and encloses the spinal cord. It consists of 33 irregular bones called “vertebrae”
The parts of the vertebral column are as follows:
· 7 Cervical vertebral column in the neck region. The first two bones called atlas and axis are important for nodding and turning the head.
· 12 dorsal or thoracic vertebrae at the back of the chest. The ribs are joined to these vertebrae
· 5 lumbar vertebrae in the waist region
· 5 sacral vertebrae are fused together to form the sacrum, a triangular shaped bone with a hollow anteriorly. The sacrum helps to form the pelvis.
· 4 small vertebrae in the tail region are fused to form a small triangular bone called the coccyx. It is attached to the lower part of sacrum.
Upper limb is divided into three regions.
Its consists of,
· Arm - located between the shoulder and elbow joint.
· Fore arm - between the elbow and wrist joints
· Hand - which is located distal to the wrist.
The rib cage forms the thorax portion of the body. It consists of 12 pairs of ribs with their costal cartilage and the sternum. The ribs are anchored posteriorly to the 12 thoracic vertebrae. It protects the heart and lungs.
Lower limb includes foot, thigh, hip and gluteal region.
Following are the 3 ear bones
Together they form a short chain that crosses the middle ear and transmit vibrations caused by sound waves from the eardrum to the liquid of the inner ear.
Throat bone (Hyoid bone): is a horseshoe shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage.