Structure of the human digestive

•   Human digestive system consists of following parts. mouth, buccal cavity, pharynx,

                       esophagus, stomach, small intestine ,large intestine , rectum, anus

                     •   The location ,gross morphology and function of the above should be explained

                     •   Dentition

                     •   Structure and role of teeth

                     •   Action that should be taken to maintain dental health

                     •   Generalized structure of gut wall

                       •   Mucosa

                       •   Sub mucosa

                       •   Muscle layers

                       •   Serosa

                     •   Explain that the arrangement of tissue layers of the alimentary canal  is according to a

                       basic plan

                     •   Major variations in the basic plan occur in the mucosa. Variations in the stomach,

                       small intestine and large intestine should be explained  in relation to their functions

                     •   Peristalsis

                     •   Associated glands

Nutrition and its need

Nutrition is the process of acquiring energy and carbon. Organisms need energy for synthesis of substances for growth and repair. Ex: Protein synthesis, active transport of substances into and out of cells against  concentration gradient (Sodium-Potassium pump), electrical transmission of nerve impulses, mechanical contraction of muscle and beating of cilia and flagella. lets find out more about nutrition.

 Different modes of nutritional patterns in the living world:

                       •    Living organisms can be grouped on the basis of their source of energy or source

                        of carbon

                       •    Organisms which have an inorganic source of carbon  such as carbon dioxide are

                        described as autotrophic

                       •    Organisms having an organic source of carbon are described as heterotrophic

                       •   Organisms using light energy are described as phototrophic

                       •   Organisms using chemical energy are described as chemotrophic

•   Autotrophs synthesize their own organic  requirements from simple inorganic

                        materials

                       •   Autotrophic nutrition is of two types:

                        •   Photoautotrophic – Energy source is sunlight and carbon source is

                           carbondioxide.eg: cyanobacteria,  green bacteria ,green plants

                        •   Chemoautotrophic- energy source is chemical substances and carbon source is

                           Carbondioxide eg; nitrifying bacteria like  Nitrobacter, Nitrosomonas

                       •   Heterotrophic organisms feed on an organic source of carbon. All  animals and

                        fungi and majority of bacteria are heterotrophic

                        •    Modes of heterotrophic nutrition

                        •    There are three types:

                            •   Saprotrophic

                            •   Holozoic

                            •   Symbiotic