The Respiratory System Chapter 17 Section 1

Key Concepts What are the functions of the respiratory system? What structures does air pass through as it travels to the lungs? What happens during gas exchange and breathing?

Key Terms Respiration Cilia Pharynx Trachea Bronchi Lungs Alveoli Diaphragm Larynx Vocal cords

Respiratory system functions How long can without breathing? Body cells need oxygen and they get it from the air you breathe. The respiratory system moves oxygen from the outside environment into the body while removing carbon dioxide and water from the body

Taking in Oxygen Oxygen is needed for the energy releasing chemical reactions that take place in your body Ex. A fire cannot burn without oxygen, cells cannot burn enough fuel to keep you alive without oxygen

Respiration vs. breathing Respiration is the process in which oxygen and glucose undergo a complex series of chemical reactions Breathing is the movement of air into and out of the lungs As a result of respiration cells release the energy that fuels growth and other cell processes

Removing Carbon Dioxide and Water Respiratory system eliminates carbon dioxide and some of the water through your lungs

Respiratory, digestive, circulatory systems Respiration could not take place without the digestive and circulatory system Respiratory system brings oxygen into your lungs Digestive system absorbs glucose from the food you eat Circulatory system carries both the oxygen and the glucose to your cells

Path of air Outside environment lungs passes through the following structures-nose, pharynx, trachea and bronchi

The Nose Air enters the body Moves into spaces called nasal cavities Some of the cells lining the nasal cavities produce mucus Sticky material moistens the air and keeps the lining from drying out Mucus traps particles such as dust

(2) Cilia are tiny hair like extensions that can move together in a sweeping motion Cilia sweep the mucus into the throat where you swallow it Stomach acid destroys the mucus along with everything trapped in it Some particles can irritate the lining of your nose or throat, you sneeze and the particles shoot out of your nose into the air

The pharynx Air enters the pharynx-throat Pharynx is shared with the digestive system-the nose and mouth connect to the pharynx

The trachea From the pharynx air moves into the trachea or windpipe Run your fingers down the center of your neck-the trachea feels like a tube with a series of ridges, the firm ridges are rings of cartilage that strengthen the trachea and keep it open Like the nose the trachea is lined with cilia and mucus Cilia in the trachea sweep upward moving mucus toward the pharynx where it is swallowed Tracheas cilia and mucus continue the cleaning and moistening of the air that began in the nose

(2) Normally only air not food enters the trachea If food does enter, and block the opening and prevents air from getting to the lungs a person chokes The epiglottis a small flap of tissue that folds over the trachea sealing off the trachea while you swallow

Bronchi and lungs Air moves from the trachea to the bronchi Lungs are the main organs of the respiratory system Left bronchus leads into the left lung same for the right side. Right bronchus leads to the right lung Inside the lungs each bronchus divides into smaller and smaller tubes resembling the branches of a tree

(2) The smallest tubes at the end of the structures look like bunches of grapes-alveoli-tiny sacs of lung tissue for the movement of gases between air and blood

Gas exchange The walls of the aveoli and the capillaries are very thin allowing certain materials to easily pass through them After air enters an alveolus, oxygen passes through the wall of the alveolus and then through the capillary wall into the blood Carbon dioxide and water pass from the blood into the alveoli You lungs can absorb a large amount of oxygen because of the large surface area of the alveoli The huge surface area of the alveoli enables the lungs to absorb a large amount of oxygen

How you breathe How many times do you breath in an average day? 20,000-the rate at which you breath depends on your body’s need for oxygen

Muscles for breathing Breathing is controlled by muscles Picture The lungs in the picture are surrounded by ribs, attached to them are the muscles, at the base is the diaphragm The diaphragm is a large dome shaped muscle

Process of breathing When you breathe your rib muscles and diaphragm expand or contract your chest-air flows in and out Inhaling-the diaphragm contracts and moves downward Exhaling-the rib muscles and diaphragm relax, reducing the size of the chest cavity-decrease in size squeezes air out of the lungs

Breathing and speaking The air that moves out of your lungs as you breathe also helps you speak The larynx is located in the top part of the trachea underneath the epiglottis