THE FUNCTION OF RESPIRATION

THE FUNCTION OF RESPIRATION

Almost every organism requires oxygen for cellular respiration:

C6H12O6 + O2 → H2O + CO2 + ATP (energy)

The job of our respiratory system is to get oxygen into our bodies, where it can then be supplied to each and every cell for cellular respiration

THE FUNCTION OF RESPIRATION

There are two parts to this process:

1. Breathing: inhalation/inspiration and exhalation/expiration

2. Gas Exchange: exchanging oxygen for carbon dioxide

a) External Respiration: exchange of oxygen and carbon dioxide between the inspired air inside the lungs and blood

b) Internal respiration: exchange of oxygen and carbon dioxide between the blood and body’s tissue cells

3. Cellular Respiration: energy releasing chemical reactions in cells

THE FUNCTION OF RESPIRATION

2. Gas Exchange

GAS EXHANGE: the two way movement of gases (oxygen, O2 and carbon dioxide, CO2) between internal (inside the organism) and external (outside the organism) environments.

OXYGEN: required to release the energy in glucose during cellular respiration

CARBON DIOXIDE: given off as a waste product

THE FUNCTION OF RESPIRATION

2. Gas Exchange

The gases can only be exchanged when they are dissolved in water because that is the only way they can diffuse through tissues

Every cell in an organism requires oxygen and needs to get rid of carbon dioxide

THE FUNCTION OF RESPIRATION

A good gas exchange system requires the following qualities:

1. Large Respiratory Surface Area

- large area for diffusion to occur

2. Moist Surface

- dissolves oxygen in the air

3. Close to Transport/Circulatory System

- delivers oxygen to circulatory system so that it can be transported throughout the body

THE FUNCTION OF RESPIRATION

Where and how do the following organisms exchange gases?

Amoeba – body surface, diffusion

Worm – body surface, diffusion

Fish – gills, diffusion

Frog – lungs, gulping and swallowing; moist outer skin, diffusion

Human – lungs, breathing

THE FUNCTION OF RESPIRATION

GAS EXCHANGE IN AQUATIC ENVIRONMENTS

Oxygen is found as a dissolved gas

Oxygen can be taken in through gills

GILLS: respiratory organ found in many aquatic animals that extracts dissolved oxygen from water, and excretes carbon dioxide

- Oxygen diffuses into the blood and circulates through surrounding capillaries

- Carbon dioxide diffuses from the blood, across the gill tissue, into the water

GAS EXCHANGE IN AQUATIC ENVIRONMENTS

GAS EXCHANGE ON LAND

Air breathing vertebrates (Ex. Reptiles, birds and mammals) rely on lungs for gas exchange

GAS EXCHANGE ON LAND

ANATOMY OF RESPIRATORY SYSTEM REQUIRED FOR BREATHING

GAS EXCHANGE ON LAND

The DIAPHRAGM and INTERCOSTALS MUSCLES work together to bring air into and out of the lungs

GAS EXCHANGE ON LAND

EXPIRATION INSPIRATION

Exhaling: air out of lungs Inhaling: air into lungs

Air pressure in lungs is GREATER than air pressure outside

Air pressure in lungs is LOWER than air pressure outside

Diaphragm relaxes Diaphragm contracts

Diaphragm moves upwards Diaphragm moves downwards

Intercostals relax Intercostals contract

Rib cage moves in and down Rib cage moves up and out

LOWER volume, HIGHER air pressure HIGHER volume, LOWER air pressure

GAS EXCHANGE ON LAND

THE PHYSIOLOGY OF GAS EXCHANGE AT THE CELLULAR LEVEL

Alveoli: thin, moist, high surface area ratio

- bathed by 4-6 L of blood every minute

Blood returning to the heart from the body is relatively low in O2 (PO2 = 40) and high in CO2 (PCO2 = 46)

This blood is pumped by the right ventricle to the lungs

In the alveoli of the lungs, gases are exchanged: O2 diffuses into capillaries and is carried by hemoglobin in

RBCs CO2 diffuses out into the alveoli and is carried as carbonic

acid

GAS EXCHANGE ON LAND

THE PHYSIOLOGY OF GAS EXCHANGE AT THE CELLULAR LEVEL

STRUCTURE GAS PRESSURE

Alveoli Oxygen 105

Capillary Oxygen 40

Alveoli Carbon dioxide 40

Capillary Carbon dioxide 46

GAS EXCHANGE ON LAND

THE PHYSIOLOGY OF GAS EXCHANGE AT THE CELLULAR LEVEL

RESPIRATORY VOLUMES

RESPIRATORY VOLUMES

Tidal Volume: Amount of air inhaled and exhaled with each normal breath

Inspiratory Reserve Volume: Maximum amount of gas that can be forcefully inhaled after a normal inhalation

Expiratory Reserve Volume: Maximum amount of gas that can be forcefully exhaled after a normal exhalation

RESPIRATORY VOLUMES

Vital Capacity: The volume of gas that can be expelled from the lungs after a full inspiration

Inspiratory Capacity + Expiratory Reserve Volume

Residual Volume: Amount of gas left in the lungs after a maximum (forced) exhalation

Total Lung Volume: The volume of gas contained in the lung at the end of maximal inspiration

Vital Capacity + Residual Volume

RESPIRATORY VOLUMES