Respiratory System

What is the purpose of respiring (breathing)? Respiration maintains homeostasis by exchanging GASES in an animal’s body In other words: To Absorb Oxygen and Release Carbon Dioxide

Why do living organisms need oxygen? Where does the carbon dioxide we breath out come from?

Respiration The energy released by respiration is used inside cells to power the group of chemical reactions, collectively called metabolism

RESPIRATION For gases, O 2 and CO 2 to diffuse across any membrane, the membrane must be moist and thin The larger the surface area the greater the rate of diffusion. DIFFUSION

RESPIRATORY SYSTEM Most animals have a respiratory system, which may use these organs/structures :

Aquatic Arthropods Gills

Must remain MOIST for diffusion to occur On land an animal with gills will DIE from a lack of oxygen (O 2 ) Gills are “feathery” and layered. This increases the SURFACE AREA

Where does oxygen in water come from? Oxygen that is dissolved in the water from the atmosphere, It is NOT the oxygen (O) in H 2 O Red dots represent dissolved oxygen in water.

What do these animals use to breathe?

Respiratory Tract-Airway The airway consists of 1.Mouth 2.Nose 3.Pharynx (throat) 4.Trachea (windpipe) Air is warmed, moistened, and filtered to remove dirt and germs

Trachea – the wind pipe The trachea is supported by cartilage rings which prevent it from collapsing In the lungs, the trachea branches into smaller and smaller tubes Bronchus Bronchioles

LUNGS: Internal Structure Alveoli: Look like clusters of grapes--- around 300 million microscopic “grapes” This is the site of gas exchange

ALVEOLI The alveoli are so efficient at gas exchange because they have a large surface area (see all the bumps and grooves)

DIAPHRAGM Name means “ partition across ” Located underneath the lungs Large muscle that pulls air into the lungs

Breathing is partially voluntary and partially involuntary

Brain Signals & Breathing Cells in the medulla oblongata (part of the brain) detect the amount of CO 2 in the blood and respond by causing the diaphragm to contract.

Intercostal Muscles In addition to the Diaphragm: Another set of muscles between the ribs, called the intercostals contract during breathing

Trace the pathway of air through the human respiratory tract

What is wrapped around the alveoli? Why? To exchange O 2 and CO 2 gases

Find and highlight the artery and vein in the alveoli VEIN ARTERY

Flash Player of Breathing 12.uthscsa.edu/studentresources/ AnatomyofBreathing3.swf

Which one has more CO 2 ? Which one has more O 2 ? = artery Vein=

LUNG CANCER Tar in the lungs: can’t exchange O 2 and CO 2

BRONCHITIS NORMAL BRONCHIBRONCHUS Clogged bronchial tube: Less air gets through

EMPHYSEMA Alveoli are broken: therefore less surface area; Less gas exchange

PNEUMONIA Alveoli (air sacs) are filled with fluid: Less O 2 and CO 2 can be exchanged

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