The Respiratory SystemThe Respiratory System

Role of the Respiratory Role of the Respiratory SystemSystem• The main role of the The main role of the respiratory systemrespiratory system

is to get oxygen from the atmosphere and is to get oxygen from the atmosphere and place it in a dissolved form into the blood.place it in a dissolved form into the blood.

• The blood will then deliver the oxygen to The blood will then deliver the oxygen to the cells of the body so they can run the cells of the body so they can run cellular respiration and make energy in the cellular respiration and make energy in the form of ATP.form of ATP.

• Ironically, the other thing needed to make Ironically, the other thing needed to make ATP is glucose and we already learned how ATP is glucose and we already learned how that was dealt with by the digestive system that was dealt with by the digestive system and placed into the blood.and placed into the blood.

Glucose + OGlucose + O22 CO CO22 + H + H22O + ATP!!!O + ATP!!!

Types of RespirationTypes of Respiration• There are three types of respiration:There are three types of respiration:1.1. External RespirationExternal Respiration – The exchange of gases across – The exchange of gases across

the inner surface of the lungs. (Alveoli & Blood)the inner surface of the lungs. (Alveoli & Blood)2.2. Internal RespirationInternal Respiration – The exchange of gases – The exchange of gases

between the blood and cells. (Capillaries & Cells)between the blood and cells. (Capillaries & Cells)3.3. Cellular RespirationCellular Respiration – The use of the oxygen to – The use of the oxygen to

make energy (ATP) inside of the cell and the make energy (ATP) inside of the cell and the mitochondria. Carbon dioxide is a waste gas that is mitochondria. Carbon dioxide is a waste gas that is produced by this process and it must be removed from produced by this process and it must be removed from the cells because it is toxic to the cells.the cells because it is toxic to the cells.

• The movement of both oxygen into the cells, and The movement of both oxygen into the cells, and carbon dioxide out of the cells is carried out by carbon dioxide out of the cells is carried out by diffusion.diffusion.

• Diffusion is a mode of passive transport in which Diffusion is a mode of passive transport in which substances move from an area or high concentration substances move from an area or high concentration to an area of low concentration.to an area of low concentration.

The Respiratory Pathway The Respiratory Pathway (I)(I)• Air enters the body through either the oral Air enters the body through either the oral

cavity (mouth) or nasal cavity (nose).cavity (mouth) or nasal cavity (nose).• The nasal cavity does a better job of The nasal cavity does a better job of

preparing the air for the “wimpy” lungs.preparing the air for the “wimpy” lungs.– It warms the air with increased surface It warms the air with increased surface

area and the large numbers of capillaries area and the large numbers of capillaries inside.inside.

– It moistens the air with mucus.It moistens the air with mucus.– It cleans the air with nose hair, ciliated It cleans the air with nose hair, ciliated

cells and mucus – sounds funny but it’s cells and mucus – sounds funny but it’s snot!snot!

• Both the nose and mouth lead back to the Both the nose and mouth lead back to the pharynxpharynx – the intersection at the back of the – the intersection at the back of the throat.throat.

The Respiratory Pathway The Respiratory Pathway (II)(II)

• After the pharynx, air After the pharynx, air moves down past the moves down past the larynxlarynx (voice box). (voice box).

• There are a pair of There are a pair of cartilage flaps called the cartilage flaps called the vocal cordsvocal cords inside the inside the larynx that vibrate as air is larynx that vibrate as air is pushed by them.pushed by them.

• Your teeth, lips and tongue Your teeth, lips and tongue mold the noise produced mold the noise produced by the vocal cords help by the vocal cords help you pronounce various you pronounce various sounds.sounds.

• The The epiglottisepiglottis lies above lies above the larynx.the larynx.

• The The tracheatrachea lies below the lies below the larynx.larynx.

The Respiratory Pathway The Respiratory Pathway (III)(III)• The The tracheatrachea is the windpipe. It extends is the windpipe. It extends

down from the throat to the chest cavity.down from the throat to the chest cavity.• The trachea is protected by The trachea is protected by cartilage cartilage

ringsrings that keep it from collapsing and that keep it from collapsing and cutting off you air supply.cutting off you air supply.

• It also has It also has mucus-producing cellsmucus-producing cells and and ciliacilia lining its inner surface to trap dirt and lining its inner surface to trap dirt and pathogens and prevent lung infection.pathogens and prevent lung infection.

• The base of the trachea divides into two The base of the trachea divides into two branches – the left and right bronchi – each branches – the left and right bronchi – each of which leads into the left and right lung.of which leads into the left and right lung.

The Bronchial TreeThe Bronchial Tree• The The bronchibronchi, at the , at the

base of the trachea, base of the trachea, begin to branch out begin to branch out into smaller into smaller bronchiolesbronchioles inside of inside of the lungs.the lungs.

• The bronchioles spread The bronchioles spread outward to the outer outward to the outer edges of the lungs until edges of the lungs until you reach the you reach the alveolialveoli..

• This branching pattern This branching pattern is known as the is known as the bronchial tree..

Gas ExchangeGas Exchange• Gas exchange takes Gas exchange takes

place in the place in the alveolialveoli of of the lungs. This is where the lungs. This is where oxygen (Ooxygen (O22) is put into ) is put into the body while carbon the body while carbon dioxide (COdioxide (CO22) is removed ) is removed from it. This movement from it. This movement is governed by is governed by diffusiondiffusion. (HI . (HI LOW) LOW)

• The alveoli look like The alveoli look like small bunches of grapes small bunches of grapes that are surrounded by that are surrounded by capillary netscapillary nets..

• Capillaries are exchange Capillaries are exchange sites in blood vessels.sites in blood vessels.

The Physiology of The Physiology of RespirationRespiration

Muscular Control of Muscular Control of BreathingBreathing

• Breathing is under control of a layer o smooth Breathing is under control of a layer o smooth muscle, called the muscle, called the diaphragmdiaphragm, that lies just below , that lies just below the lungs.the lungs.

• The lungs reside in the thoracic cavity – the hollow The lungs reside in the thoracic cavity – the hollow compartment in the chest. The lungs are like compartment in the chest. The lungs are like sponges and can expand or constrict to fit within sponges and can expand or constrict to fit within the space of the thoracic cavity.the space of the thoracic cavity.

• The diaphragm contracts and moves downward – The diaphragm contracts and moves downward – this makes the thoracic cavity larger and the lungs this makes the thoracic cavity larger and the lungs expand and take in more air to fill the space. This expand and take in more air to fill the space. This is is inhalationinhalation..

• When the diaphragm relaxes, it moves back up When the diaphragm relaxes, it moves back up and makes the thoracic cavity smaller – the lungs and makes the thoracic cavity smaller – the lungs are now squeezed and the air is forced out of are now squeezed and the air is forced out of them. This is them. This is exhalationexhalation..

Muscular Control of Muscular Control of BreathingBreathing

Nervous Control of Nervous Control of BreathingBreathing• The The medulla oblongatamedulla oblongata is the part of the brain is the part of the brain

that controls your breathing rate. It has that controls your breathing rate. It has chemoreceptorschemoreceptors in it that measure the acid in it that measure the acid levels of blood. (pH is the key.)levels of blood. (pH is the key.)

• As more COAs more CO22 is dumped into the blood by the is dumped into the blood by the cells, there is more need to breathe and get rid cells, there is more need to breathe and get rid of that COof that CO22. The CO. The CO22 mixes with the water in the mixes with the water in the blood to form blood to form carbonic acidcarbonic acid..

COCO22 + H + H22O O H H22COCO33 (aq) (aq)

• More COMore CO22 means more carbonic acid in the blood means more carbonic acid in the blood and a lower pH. This is sensed by the medulla and a lower pH. This is sensed by the medulla oblongata and it sends an impulse down to the oblongata and it sends an impulse down to the diaphragm to move faster and your breathing diaphragm to move faster and your breathing rate increases.rate increases.

That’s All I Got…That’s All I Got…