MEDMENTORS

This system develops from the embryonic endoderm &it consists of the oral cavity, esophagus,  stomach, small and large intestine, rectum and anus. It also includes accessory glands such as  the salivary gland, liver and pancreas.  The system functions as to receive food substances through the mouth, prepare it for digestion,  digest the food and then absorb it mainly by the small intestine.  The walls of the digestive system components are made up of 4 main layers; the mucosa,  submucosa, muscularis and serosa (adventitia).  MUCOSA: This layer is made of an epithelium and underlying lamina propria.  The epithelium is simple columnar all over the gastrointestinal tract except at the pharynx,  mouth, esophagus and over parts of anal canal which are stratified squamous non keratinized to prevent abrasion.  The epithelium serves protective function at esophagus and anal canal, secretory function at oral  cavity, esophagus, stomach and intestine & absorptiv

The respiratory system is a body system made up branching system of tubes and the lungs  responsible for the exchange of respiratory gas between the body and the atmosphere. The  respiratory tract can be divided anatomically and functionality.  a. Anatomically: into upper respiratory tract and lower respiratory tract.  The upper respiratory tract includes the nose and nasal passages, paranasal  sinuses, the Pharynx, and is the portion of the larynx above the vocal cords  (glottis), cricoid cartilage and sternal angle. The lower respiratory tract is  derived from the foregut includes the portion of the larynx below the vocal  cords, trachea, bronchi and bronchioles. The lungs can be included in the lower  respiratory tract or as separate entity and include the respiratory bronchioles,  alveolar ducts, alveolar sacs, and alveoli. b. Functionally: into conducting part and respiratory part.  The conducting part is the part through which air passes and enters the l