UNIT 1.- THE HUMAN BODY 1.- Life Processes 1.1.- Nutrition Nutrition is the process of getting energy from food. Four body systems participate in nutrition. 1. Digestive system: we digest food and absorb nutrients 2. Respiratory system: we get the oxygen that we need to obtain energy from food. 3. Circulatory sysytem: our blood carries nutrients and oxygen around our body. 4. Excretory system: we expel waste from our body.
1.2.- Reproduction Reproduction is the ability to have offspring similar to ourselves. -
Men and women have different reproductive organs. People can reproduce when they are adults. Women carry babies in their womb. Parents and children share physical characteristics.
1.3.- Sensitivity Sensitivity is the ability to detect and respond to information about the environment. 1.- We detect the information with our five senses. 2.- The nerves send the information to the brain which thinks of a response. (Nervous system) 3.- Nerves send the message from the brain to bones and muscles that carry out the response to move our body. (Locomotor system)
4.- The 5 senses
A) The sense of sight
We use the sense of sight to distinguish the shape, colour, size and distance of objects. The eyes are the organs of sight. Eyelids, eyebrows and eyelashes protect the eyes. First, light passes through the cornea and then through the pupil that is a hole in the centre
of the iris. The iris is a coloured ring. Behind the iris is the lens that helps the eye to focus. At the back of the eye, the retina captures the light and creates and image. Finally the optic nerve takes the information to the brain. B) The sense of hearing We use the sense of hearing to distinguish sounds. The ears are the sense organs of hearing . The pinna captures the sound that travels through the ear canal to the ear drum, which vibrates with the sound. The small bones move when the eardrum vibrates. The cochlea captures the sound vibrations and the auditory nerve takes the information to the brain. C) The sense of touch. We use the sense of touch to feel temperature, textures and pain. The skin (largest organ in our body) is the organ of touch and has a lot of touch receptors which send the information to the brain through the nerves. D) The sense of taste You use the sense of taste to distinguish different flavours (sweet, salty, sour and bitter). The tongue is the organ of taste and is covered with taste buds which send the information to the brain through the nerves. E) The sense of smell We use the sense of smell to distinguish smells and the nose is the sense organ of smell, The smell enters the nose through the nostrils and reach the nasal cavity. The nasal cavity has smell receptors which send the information to the brain through the olfactory nerve.