Chapter 7 Assignment #1
Distinguish between axial and appendicular skeletons.
Appendicular Skeleton Consist of bones of upper and lower limbs and bones that anchor limbs to axial skeleton. (Limbs, appendages -arms and legs- and girdles- shoulder and pelvic) (Pectoral girdle, Scapula, Clavicle, Upper limbs, Humerus, Radius, Ulna, Carpals, Metacarpals, Phalanges, Pelvic girdle, Pelvis, Lower limbs, Femur, Tibia, Fibula, Patella, Tarsals, Metatarsals, Phalanges) Axial Skeleton Consist of bony and cartilaginous parts that support and protect organs of the head, neck, and trunk. (Skull, Cranium, Hyoid bone, Vertebral column, Sacrum, Coccyx, Thoracic Cage, Ribs, Sternum)
What are the five major parts of a long bone? Describe.
Epiphysis; At each ends of the long bone and is an expanded portion that forms a joint with another bone Articular Cartilage; On outer surface of epiphysis and coats it with layer of hyaline cartilage (articular cartilage) Diaphysis; Located between the epiphysis and is the shaft of the bone Periosteum; a tough, vascular covering of fibrous tissue, it completely encloses the bone (except AC), Firmly attached to the bone, helps for and repair bone tissues Compact Bone; Outer part of bone
How do the parathyroid hormone and calcitonin affect calcium storage and use? Why is it important to maintain blood calcium levels?
Hormone regulate opposing process of resorption and deposition of calcium, ultimately making the total mass of of bone tissue remain nearly constant. In bone cancer, abnormally active osteoclasts destroy bone tissue, cancer of prostate gland can have opposite effect if cancer cells reach bone marrow, cells stimulate osteoblast activity, igniting formation of new bone on the surface of bony plates.When blood calcium is low in calcium, parathyroid hormone stimulates osteoclasts to break down bone tissues, releasing calcium salt to the blood, when it is high, osteoblasts form bone tissue and store calcium salt. Maintaining sufficient blood calcium levels is important in muscle contraction, nervous impulse conduction, blood clotting, and other physiological processes.
Osteoclasts
Large, multinucleated cells that break down the calcified matrix, originates in bone marrow when single-nucleated white blood cells fuse Secretes an acid that dissolves inorganic components of the calcified matrix, lysosomal enzymes digest the organic compounds, after disposal of matrix, bone-building osteoblasts invade the region and deposit new bone tissue in place of calcified cartilage (Bone-destroying cells)
How do osteoclasts and osteoblasts remodel bone?
Osteoclasts resorb bone matrix, and osteoblasts replace it.
What are the functions of the skeletal system? (List at least 3.)
Produce blood cells Mineral Homeostasis - Stores and release minerals, when needed, and fats Protection - The cranium and ribs protect the brain and vital organs in the chest. Shape - gives shape to the body and makes you tall or short. Support - Holds your vital organs in place. Movement - Skeletal muscle is attached to bone so it pulls on the bone when it contracts.
How does an adult skull differ from an infant skull?
Red marrow occupies cavities of most bones in an infant, with increasing age, yellow marrow replaces it.
What is the epiphyseal plate? What happens there?
The epiphyseal plate, also known as the growth plate is a hyaline cartilage (in lining bones of joints, tissue provides smooth surfaces, enabling tissues to move/slide easily over each other, e.g. facilitating smooth movements at joints, also provides flexibility and support) plate in the metaphysis at each end of a long bone. It is the area of growing tissue near the ends of the long bones in children and adolescents, each long bone has at least two growth plates; one at each end, it also determines the future length and shape of the mature bone.
What is the difference between red and yellow marrow?
Two type of bone marrow in medullary cavity in long bones (marrow, a soft, netlike mass of long bones and of compact bone tissue) Red Marrow (Myeloid Tissue) Red blood cells, platelets (for blood clotting) and most white blood cells arise in red marrow Helps body in everyday functions Yellow Marrow Some white blood cells develop, produces and stored more of fat cells, cartilage and bones Inactive in blood cell reproduction Color due to higher number of fat cells Helps body survive extreme cases of hunger and blood loss
Osteoblasts
When some primitive connective tissue cells enlarge and differentiate into bone-forming cells, it becomes active within membranes and deposit bony matrix around themselves, so spongy tissues form in all directions within the layers of primitive connective tissues, cell of the membranous tissues (outside developing bone) give rise to periosteum. Inside periosteum, osteoblasts form layer of compact bone over the surface of newly formed spongy bone. Osteocytes - When matrix completely surrounds osteoblasts (Bone-building (forming) cells)
