Download Topic: Key Terms

Name:____________________
Key Terms
respiration
cilia
pharynx
trachea
bronchi
lungs
alveoli
diaphragm
larynx
vocal cords
Topic:The Respiratory System
Date:__________
pp. 112­120
• How does the Respiratory System function?
The respiratory system moves O2 from the outside environment into the body. It also removes CO2 and H2O from the body.
• Why does the body take in O2?
Your body needs to take in O2 to burn in order to release the energy from food. This process happens in the cells of your body and is called respiration. This process is not the same as breathing!
• Why does the body remove CO2 and H2O?
Both CO2 and H2O are waste products of respiration and are removed from the body by the lungs.
• What kinds of systems work together?
In order for respiration to take place both your digestive and circulatory systems have to work in coordination with your respiratory system. Your digestive system has to absorb glucose from the foods you eat and your circulatory system has to deliver the glucose and O­2 to your cells.
• What is the path of air?
As air passes through the respiratory system, air is filtered, warmed, and moistened. From the outside environment to the lungs, air passes through the following structures: nose, pharynx, trachea, and bronchi. This process only takes a few seconds.
• What happens to air as it passes through the nose?
As air passes through the nose it passes into nasal cavities which are lined with mucus. This sticky material traps particles and keeps the air from drying out. The cells in the nasal cavities are also lined with cilia, tiny hairlike extensions that can move together in a sweeping motion. These sweep mucus from the throat where you can swallow it and stomach acid will then destroy any harmful particles. If these particles irritate the lining of your nose or throat, you will sneeze and that will force the particles out of your body back into the air.
• What happens to air as it passes through the pharynx?
The pharynx, or the throat, is the next structure air passes through on its way to the lungs. This is the only part of the respiratory system that is shared with the digestive system and both the nose and throat connect to the pharynx.
• What happens to air as it passes through the trachea?
The next stop for air is the trachea, or windpipe. The trachea is lined with rings of cartilage for strength and to keep it open. Like the nose it is also lined with cilia and mucus. If these particles are irritated, you cough, which like a sneeze also sends particles back into the air. If food enters the trachea, a person can choke, as the food will block air from getting to the lungs. Luckily we have a structure called an epiglottis, which is a flap of tissue that seals the trachea when you swallow preventing food from going down.
Name:____________________
Topic:The Respiratory System
Date:__________
pp. 112­120
• What happens to air as it passes through the bronchi and lungs?
After the trachea, air moves into the bronchi, or passages that lead air directly into the lungs. Lungs are the main organs of the respiratory system which contain the structures necessary for air exchange. As each bronchus enters a lung it branches into smaller structures in a pattern similar to branches of a tree. At the end of each branch are structures that look like bunches of grapes. These "grapes" are called alveoli, which are tiny sacs of lung tissue specialized for the movement of gases between air and blood. Each alveolus is surrounded by a network of capillaries. This is where diffusion takes place and O2 goes into the blood and CO­2 and H2O go into the air in the lungs to be breathed out.
• What is gas exchange?
After air enters the alveolus, O2 passes through the thin wall of the alveolus and then through the thin wall of the capillary into the blood. CO2 and H2O pass from the blood into the alveoli. This whole process is known as gas exchange.
• How does gas exchange occur?
RBCs in the blood in the capillary around an alveolus will pick up O2 as it diffuses across the membrane by attaching to the hemoglobin that is in the RBC. At the same time, blood will drop off CO2 and H2O, which will diffuse across the membrane into the alveolus, which will then be exhaled.
• How does surface area affect gas exchange?
Your lungs can absorb a lot of O2 because it has a large surface area (SA). If you could lay out all your millions of alveoli on a flat surface, it would be the size of a tennis court! The more SA you have, the more O2 your lungs can absorb.
• How do you breathe?
In an average day, you might breathe more than 20,000 times. How much you breather depends on your body's need for O2. The more O2 you need, the faster you breathe.
Name:____________________
Topic:The Respiratory System
Date:__________
pp. 112­120
• What are the muscles for breathing?
Breathing is controlled by muscles. These muscles include ones attached to the ribs and the diaphragm, a large, dome­shaped muscle that plays an important role in breathing.
• What is the process of breathing?
When you breathe, the actions of your rib muscles and the diaphragm expand or contract your chest. As a result, air flows in or out. When you inhale, the rib muscles contract which lift the chest wall upward and outward. At the same time, the diaphragm contracts and moves downward which makes the chest cavity larger. This causes the pressure of the air inside your lungs to decrease. This change in pressure forces air to rush into your lungs in the same way air is sucked into a vacuum cleaner.
When you exhale, the opposite motions occur. The rib muscles and diaphragm relax which reduces the size of your chest cavity. This increases the pressure inside your lungs and air is squeezed out like pushing on a plastic ketchup bottle to get the ketchup out.
• How are breathing and speaking related?
The air that moves out of your lungs also helps you to speak. The larynx, or voice box is located in the top part of your trachea, under the epiglottis. In the larynx, there are two vocal cords, or folds of connective tissue that produce your voice, that stretch across the opening. As air ruches over these cords when you exhale, the molecules vibrate, which creates a sound, which is your voice!