HSCI 1105 Lecture Notes - Lecture 4: Gastric Acid, Sodium Bicarbonate, Salivary Gland
Document Summary
Food provides energy as well as all the raw materials to build body structures and synthesize regulatory molecules. All matter on earth including our bodies are made of atoms which cannot be broken down by chemical means. Atoms of different elements have different characteristics (carbon, hydrogen, oxygen and nitrogen are the most. Atoms are linked by chemical bonds to form molecules abundant in our body and in the foods we eat. ) In all living systems, molecules are organized into structures that form cells, the smallest unit of life. Cells of similar structure and function are organized into tissues (4 types in human body) The tissues are organized in varying combinations into organs. Most organs do not function alone but are part of a group of cooperative organs called organ systems. Digestive system primarily responsible for the breaking down and movement of nutrients into the body. Endocrine system secretes chemical messengers that help regulate food intake and absorption.