nutrients in humans 6

• nutrients is the process which organism obtain food and energy for growth, repair and maintenance of the body
• • nutrition consists of the following processes: ingestion, digestion, absorption, assimilation
• 1. ingestion, food is taken into the body
• 1. digestion, large food molecules are broken down into smaller soluble molecules
• 1. absorption and assimilation, digested food molecules are absorbed into the cell, these food molecules are converted into new protoplasm or used to provide energy
• 1. egestion, undigested food is removed from the body
• digestion of food begins in the mouth by the teeth, salivary gland and tongue
• pharynx connects the buccal cavity to the esophagus and larynx
• air passes to the trachea while food passes into the oesophagus
• stomach secretes gastric juice containing hydrochloric acid which breaks down proteins
• small intestine has three parts; duodenum, jejunum and ileum and is 6m long
• larynx has a slit like opening called glottis covered by the epiglottis
• during swallowing the larynx moves upwards and the epiglottis covers the glottis
• the walls of the oesophagus is made up of two layers of muscles: longitudinal and circular
• amylase digest starch
• the stomach is a distensible muscular bag
• food in the stomach is digested by gastric juices secreted by the gastric glands
• large intestine consists of colon and rectum it is 1.5m long
• liver, gall bladder and pancrease help in digestion of food in the gut
• liver is made up of 5 lobes, and the cells of the liver secretes bile
• gall bladder store bile temporarily
• pancrease secretes pancreatic juices which help digest food