AP Biology 2008-2009

Respiratory System

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DO NOW Brain Pop Video: Respiratory System

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Requires respiratory surface for the exchange of gases (O2 & CO2)

The surface must be: Thin Moist In contact with O2 A transport system

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Why do we need a respiratory system?

Need O2 in for cellular respiration make ATP

Need CO2 out waste product

O2

food

ATP

CO2

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HUMAN RESPIRATORY SYSTEM

Composed of 2 lungs and the system of tubes that connects them to the outside

* Lungs are in the chest cavity

diaphragm = muscle that separates lungs from abdomen

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Lungs

alveoli

trachea bronchi bronchioles alveoli

capillaries(circulatory system)

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Lungs Structure

spongy texture high surface area more absorption of O2

alveoli small air sacs

moist lining mucus traps dust,

pollen, particles covered by cilia

hair-like extensions of cells

move mucus upward to clear out lungs

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Passage of Air: Nose (nostrils) Nasal cavity Lined with ciliated cells

capable of producing mucus

- Hair catches dust particles

- Air passing through the nasal cavity is moistened, warmed and filtered in the nasal cavity

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Pharynx (throat) - in the back of the oral cavity where the nasal cavity joins

Trachea (windpipe) – top part is the larynx with vocal cords cartilage rings hold trachea open lined with ciliated tissues that sweep dust

particles up and out so they may be swallowed or expelled

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2 Bronchi – branch from the end of the trachea and lead to the 2 lungs

** also ringed with cartilage and lined with ciliated mucous membrane

Bronchioles – highly branches tubules that subdivide from the ends of the bronchi and become progressively smaller as the pass deeper into the lungs

no cartilage rings

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Alveoli – air sacs where gas exchange occurs surrounded by

capillaries carry away oxygen

absorbed in the moist lining so it can be transported to body tissues

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Do Now Page 5 of the Respiration Packet

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Breathing:

Muscles and ribs + diaphragm = inhalation and exhalation to fill and empty lungs – 2x per minute

Inhale: Ribs up and out Diaphragm

flattens Volume increases Pressure

decreases

Exhale: Ribs down and in Diaphragm arches Volume decreases Pressure

increases

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Moving gases into bloodstream Inhale

O2 passes from

alveoli to blood by diffusion

Exhale CO2 passes from

blood to alveoli by diffusion

capillaries(circulatory system)

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Gas exchange: Diffusion of gases Gases move by diffusion from high to low

concentration capillaries are thin-walled tubes of circulatory

system alveoli are thin-walled sacs of respiratory

system

blood lungs

CO2

O2

CO2

O2

blood body

CO2

O2

CO2

O2

capillaries in lungs capillaries in muscle

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Negative pressure breathing Diaphragm moves down & expands chest

cavity pulls air into lungs

inhale exhale

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Automatic Brain Control You don’t have to think to breathe! Primitive parts

of brain coordinatebreathing medulla & pons measure blood pH

CO2 = pH (acid) coordinate

breathing, heart rate & body’s need for energy

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Breathing and Homeostasis Homeostasis

keeping the internal environment of the body balanced

need to balance O2 in and CO2 out need to balance energy (ATP) production

Exercise breathe faster

need more ATP bring in more O2 & remove more CO2

Disease poor lung or heart function = breathe faster

need to work harder to bring in O2 & remove CO2

O2

ATP

CO2

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Disorders of the Respiratory System Emphysema Asthma Cancer

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Effects of Smoking Constricts or narrows the blood

vessels Causes blood pressure to rise and

make the heart work harder Circulation deceases

Smoking is the major cause of heart disease

Can cause chronic bronchitis (inflammation of the bronchi)

Reduces life expectancy

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Smoking Can cause emphysema Nicotine is addictive and

a powerful drug which makes it difficult to quit smoking

May worsen previous conditions such as asthma

Can lead to cancers of the mouth, throat, and lungs

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Gills: getting O2 out of water Gills are gas exchange

membranes outside of the body thin tissue

high surface area must stay wet

lots of blood vessels gas exchange

O2 into blood

CO2 out to water

gills

water

Just keepswimming…