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Respiratory System Homework

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Respiratory System Homework Describe the ways in which air is made to enter and leave the lungs during breathing. When breathing in the intercostals and the diaphragm contracts. Thorax volume increases and the air is drawn in the lungs. Air is drawn in the thorax, and then through the sternum, which after goes into the lungs. After the muscles between the ribs pull the rib cage and sternum up and out and finally the diaphragm moves down. When breathing out the intercostals and diaphragm relaxes. Thorax volume decreases and the air is forced out of the lungs. ...read more.


The job of the red blood cell is to carry oxygen to all the cells in the body. They have a flying doughnut shape to give maximum surface area for absorbing oxygen. In the lungs, haemoglobin absorbs oxyhaemoglobin. In body tissues the reverse happens to release oxygen to the cells. They have no nucleus to make more room for haemoglobin. The white blood cells jobs are to be defence against disease. They have a large nucleus. They absorb unwelcome microbes (bacteria). They also produce anti bodies to fight bacteria and antitoxins to neutralise the toxins produced by bacteria. ...read more.


Describe the events occurring during digestion, and the enzymes and juices involved, until the digested food enters the villi. The event that occurs during digestion, saliva moistens the food. Contains amylase, which begins the digestion of starch in the mouth. The pits in the stomach wall produce gastric juice, which contains hydrochloric acid and the enzymes pepsin and rennin. The bile, which is produced in the liver, neutralises acid from the stomach and breaks fats into small droplets, which are easier for the enzymes to digest. Pancreatic juice contains four different enzymes, which digest carbohydrate, fat and protein. Absorption occurs when nutrients pass through its cells and into the blood and lymph vessels. ...read more.

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