THE RESPIRATORY SYSTEM Nasal cavities and paranasal sinuses ( 13-1 ) The nasal cavities and paranasal sinuses provide an extensive surface area for: 1. Warming and moistening air. 2. Filtering dust particles present in the inspired air. In addition, the…
THE CARDIOVASCULAR SYSTEM ( 12-1 ) The circulation is divided into the systemic or peripheral circulation and the pulmonary circulation . Arteries transport blood under high pressure and their muscular walls are thick. The veins are conduits for transport of…
ORGANIZATION AND TYPES OF SKIN ( 11-1 ) The integument is the largest organ of the body. It consists of two components: 1. The skin . 2. The epidermal derivatives , such as nails, hair and glands (sweat and sebaceous…
COMPONENTS OF THE IMMUNE–LYMPHATIC SYSTEM ( 10-1 and 10-2 ) The lymphatic system includes primary and secondary lymphoid organs . The primary lymphoid organs produce the cell components of the immune system (see 10-1 ). They are: 1. The bone…
EYE ( 9-1 ) The eyeball consists of three tunics or layers , which, from outside to inside, are: 1. The sclera and the cornea . 2. The uvea . 3. The retina . Three distinct and interconnected chambers are…
Development of the nervous system ( 8-1 and 8-2 ) The central nervous system (CNS) develops from the primitive ectoderm (see 8-1 ; see Box 8-A and Box 8-B ). A simple epithelial disk, the neural plate , rapidly rolls…
SKELETAL MUSCLE ( 7-1 ) Muscle cells or fibers form a long multinucleated syncytium grouped in bundles surrounded by connective tissue sheaths and extending from the site of origin to their insertion. The epimysium is a dense connective tissue layer…
BLOOD Blood consists of cells and plasma . These components may be separated by centrifugation when blood is collected in the presence of anticoagulants. The sedimented red blood cells (RBCs) constitute about 42%–47% of blood volume. This percentage of erythrocyte…
OSTEOGENESIS (Bone development or ossification) Bone can develop either directly from an initial cell condensation of the mesenchyme (intramembranous ossification) or by gradual replacement of a pre-existing tissue, the cartilage, which acts as a template (endochondral ossification; bone formation inside…
Classification ( 4-1 to 4-3 ) Unlike epithelial cells, which are almost free of intercellular material, connective tissue cells are widely separated by components of the extracellular matrix (ECM). In addition, epithelial cells lack direct blood and lymphatic supply, whereas…