Skeletal System Anatomy and Physiology PDF

TOPIC 3: SKELETAL SYSTEM FUNCTIONS OF THE SKELETAL SYSTEM SUPPORT - forms the internal framework that supports and anchors all soft organs. - bones are “steel girders” and “reinforced concrete” - The bones of the legs act as pillars to support the bo...

TOPIC 3: SKELETAL SYSTEM FUNCTIONS OF THE SKELETAL SYSTEM SUPPORT - forms the internal framework that supports and anchors all soft organs. - bones are “steel girders” and “reinforced concrete” - The bones of the legs act as pillars to support the body trunk when we stand and the rib cage supports the thoracic wall. PROTECTION - The arrangement of bones in the skeleton provides protection for the internal organs. ALLOWS MOVEMENT - Skeletal muscles attached to bones by tendons use the bones as levers to move the body and its parts. STORAGE - Bones serve as storehouse for important minerals and fats a. Fat is stored in the internal cavities of bones (bone marrow). b. Calcium (in salt form) and Phosphorus is deposited in the bones. Calcium (in ion form) are present in the blood at all times. Hormones control the movement of calcium to and from the bones and blood according to the needs of the body. BLOOD CELL FORMATION - Red blood cells (RBCs), White blood cells (WBCs) and platelets are formed in the red bone marrow of spongy bones. - Hematopoiesis is the formation and Compact and Spongy bones make up the long maturation of blood cells. If hemocytoblasts bones in the body which are dense hard bones that (stem cells in the red bone marrow) commits provide strength, structure and mobility. to become a proerythroblast cell, then it will develop into a new RBC. CLASSIFICATION OF BONES - An adult skeleton is composed of 206 bones which come in a variety of sizes and shapes. - The bones are the primary skeletal structure that supports muscles and gives shape to the body. 1|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA  GROSS ANATOMY OF THE BONE - For the best visualization of all of the parts of the bone, the structure of the bone under a gross anatomy will be used. - The long bone is composed of two parts: the diaphysis and the epiphysis 2|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA  3|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA  4|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA A. Axial Skeleton SKULL - formed by 22 bones (8 cranial flat bones and 14 facial bones) Also found in the head are 3 small bones in the middle ear of each side and 1 hyoid bone A1. Cranium (8) - Cranial bones form the braincase (lined with meninges) that encloses and protects the brain, eyes, and ears 5|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA SUTURES - immovable joints between cranial bones - they do not move, instead the term joint or articulation is used for any junction or seam of two bones - In a suture, the sawtooth or the serrated edges of adjacent bones fit into each other. These interlocking projections prevent sliding or shifting of the bones if the skull is subjected to a blow or pressure. 6|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA PARANASAL SINUSES - air cavities located in the maxillae and frontal, sphenoid, and ethmoid. - As the name paranasal suggests, they open into the nasal cavities and are lined with ciliated epithelium continuous with the mucosa of the nasal cavities. - We are aware of our sinuses only when they become “stuffed up,” which means that the mucus they produce cannot drain into the nasal cavities. (fever, cold, allergy) FUNCTION: 1. makes the skull lighter 2. provide resonance for the voice The FORAMEN MAGNUM (Latin: great hole) - is a large oval opening (foramen) in the occipital bone of the skull. - It is one of the several oval or circular openings (foramina) in the base of the skull. o The spinal cord, an extension of the medulla oblongata, passes through the foramen magnum as it exits the cranial cavity. The spinous and transverse process are projections for the attachment of the muscles that bend the vertebral column. 7|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA The supporting part of a vertebra is its body; the bodies of adjacent vertebrae are separated by discs of fibrous cartilage. These disc cushion and absorb shock and permit some movement between vertebrae (symphysis joints). Since there are so many joints, the backbone as a whole is quite flexible. B. Appendicular Skeleton (126 bones) - bones of the limbs (appendages) & the pectoral and pelvic girdles which attach the limbs to the axial skeleton 8|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA The pelvic girdle is composed of 2 hip/coxal bones. Each hip bone consists of ilium, ischium and pubis. These three fuse at the deep socket called acetabulum that receives the head of the thigh bone. 9|Page ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA  From each center of ossification, bone growth radiates outward while calcium salts are deposited in the collagen of the model of the bone. The rest of the embryonic skeleton is first made of cartilage, and ossification begins in the third month of gestation in the long bones. - Fibroblasts(spindle-shaped connective tissue cells) at this stage become more specialized and differentiate into osteoblasts, which produce bone matrix FONTANELS - areas of fibrous connective tissue remaining between the bones of the skull - referred to as “soft spots”. permit compression of the baby’s head during birth without breaking the still thin cranial bones. permit the growth of the brain after birth. - By the age of 2 years, all the fontanels have become ossified, and the skull becomes a more effective protective covering for the brain. The long bones also develop centers of ossification in their epiphysis. In long bones, growth occurs in the epiphyseal discs at the junction of the diaphysis with each epiphysis. An 10 | P a g e ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA epiphyseal disc is still cartilage, and the bone grows in length as more cartilage is produced on the epiphysis side. - On the diaphysis side, osteoblasts produce bone matrix to replace the cartilage. Between the ages of 16 and 25 years (influenced by estrogen or testosterone), all of the cartilage of the epiphyseal discs is replaced by bone. This is called closure of the epiphyseal discs (or we say the discs are closed), and the bone lengthening process stops. 11 | P a g e ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA  12 | P a g e ANATOMY AND PHYSIOLOGY FULL MC 1 DISCUSSION by DR. ANDREA CHRISTINE TY CAMPANA