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 bodyMoves into spaces called nasal cavitiesSome of the cells lining the nasal cavities

produce mucusSticky material moistens the air and keeps

the lining from drying outMucus 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-throatPharynx 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 bronchiLungs are the main organs of the

respiratory systemLeft 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