11.1 The Function of Respiration

SBI 3U1

What is the function of the Respiratory System?

To that ensure that oxygen is brought in and carbon dioxide is removed from each cell in the body….

The 4 stages of Respiration:

1) Breathing- inspiration/inhalation and expiration/exhalation

2) External Respiration- exchange of gases between lungs and blood

3) Internal Respiration- exchange of gases between blood and cells

4) Cellular Respiration- energy-releasing reactions inside the cells

RECALL: GAS EXCHANGE

BREATHING: Inhalation & Exhalation

Inspiration (breathing in, inhaling)Expiration (breathing out, exhaling)

EXTERNAL RESPIRATION: Gas Exchange

Exchange of O2 and CO2 between the inspired air in the lungs and the blood (from the alveoli to the capillaries)

INTERNAL RESPIRATION: Gas Exchange

Exchange of O2 and CO2 between blood and body’s tissue cells ( from blood-> somatic cells)

CELLULAR RESPIRATION–Occurs in the

mitochondria of cells

–Uses O2 and glucose to produce CO2 oxide and water

–Produces energy ( ATP)

Respiratory Surfaces

There are 2 requirements for respiratory surfaces:

1) They must be large enough for gas exchange to occur quickly enough to meet the body’s needs.

2) They must be moist so gases can dissolve

Types of Respiratory Surfaces in Animals

1)Outer Skin• entire outer skin is used

• diffusion transports O2 and CO2 in and out of cells from blood

• organism must live in moist environments (ie. Worms)

2)Gills• extensions of folds in the body

surface that increase surface area• diffusion transports gases to blood

and cells• organisms live in aquatic

environments (ie. Fish)

Types of Respiratory Surfaces in Animals cont’d…

3)Tracheal System• Ie. insects • internal system of branching

respiratory tracheae (tubes)• tracheae connect cells directly

to environment for gas exchange (blood not required)

4)Lungs• Ie. large animals/ humans• lungs contain sacs lined with a

moist surface (epithelium); these sacs increase surface area

• blood transports gases to cells by diffusion

The Mechanisms of Breathing• Brain

– co-ordinates breathing movements– Monitors volume of air in the lungs/gas in the

blood

• Diaphragm and Rib Muscles– Control air pressure in lungs

Air Pressure in the Lungs

Inspiration (inhalation) • intercostal muscles and the diaphragm contract• the rib cage moves up and out• the volume increases, the pressure inside the lungs

decreases.

Expiration (exhalation) • The diaphragm and intercostal muscles relax• The rib cage moves down and inward• volume decreases, pressure inside the lungs increases

*Note: Inhalation- diaphragm contracts and moves down

Exhalation-Diaphragm relaxes and moves up

Tidal volume-the volume of air that is inhaled and exhaled in a normal breathing movement (taken when body is at rest).

Inspiratory reserve volume -the additional volume of air that can be taken into the lungs beyond a regular (tidal) inhalation.

Expiratory reserve volume- the additional volume of air that can be forced out of the lungs beyond a regular (tidal) exhalation.

Vital capacity (total lung volume) -the total volume of gas that can be moved into or out of the lungs.tidal volume + inspiratory reserve volume + expiratory reserve volume = vital capacity

Residual volume -the amount of air that remains in the lungs and passageways even after a full exhalation.

 

 

 

 

Measuring Respiratory VolumeUNIT 4 Chapter 11: The Respiratory System Section 11.1

Spirographs represent the amount of air that moves into and out of the lungs with each breath as measured by a spirometer.

 

 

 

Spirographs

UNIT 4 Chapter 11: The Respiratory System Section 11.1

Homework:

Read and make notes 11.1 Complete pg. 444 #1-6 and pg. 447 #9-11