The Respiratory System

Anatomy

Think about it…

Why do we need to breathe?

How does oxygen get into body cells?

How is carbon dioxide removed from the

lungs?

To maximize gas exchange, athletes will

often train themselves to inhale and

exhale through the nose and mouth at

the same time.

Can you do it?

Intro Video

https://www.youtube.com/watch?v=hc1YtXc_84A

Why do we Breathe?

Most organisms on Earth

are aerobic.

Require oxygen to survive

Oxygen is necessary to

carry out cellular respiration.

Cellular respiration

produces carbon dioxide

as a waste product.

Gas Exchange

The basic function of the respiratory system is gas

exchange:

To make sure oxygen can enter each cell; and

To make sure carbon dioxide can leave each cell.

Respiratory System Requirements

The respiratory system of every organism as two

requirements:

Respiratory surface: surface area for gas exchange.

Moist environment: to ensure gases are dissolved.

Different Kinds of Respiration

Breathing

Inspiration: taking air into the lungs.

Expiration: breathing out.

External respiration: exchange of oxygen and carbon

dioxide between air and blood.

Internal respiration: exchange of

oxygen and carbon dioxide

between blood and cells.

Cellular respiration: the series

of chemical reactions that

take place in the

mitochondria of cells.

Structures of the Human Respiratory

System

Upper Respiratory Tract

Respiration begins when we inhale air through the mouth or nasal cavity. The air then travels through the pharynx, larynx and trachea to get to the lower respiratory tract.

Nasal Cavity

3 functions:

Air is cleaned: Bacteria, dust, other

particles in the air are trapped by small

hairs(cilia) and mucus.

Air is moistened: Mucus wets air to

protect tissues.

Air is warmed: Enters through nostrils

where air is warmed by capillaries.

Nasal Cavity

Upper Respiratory Tract (cont’d)

Uvula - prevents food from travelling

into the nasal cavity.

Pharynx - tube common to both the

respiratory and digestive systems.

Larynx (voice box) - located at

the opening of the respiratory

passageway.

Contains vocal cords

Larynx

Connects pharynx to trachea.

Voice box made of cartilage (flexible connective tissue).

Epiglottis closes to prevent food from entering windpipe.

Vocal Cords

Muscles that pull on cartilage inside larynx.

While breathing, vocal cords are relaxed and no sound is

made.

Muscles tighten to produce sound.

Air passing cords cause vibrations that make sound.

The tighter the cords, the higher the pitch.

Breathing Speaking

Trachea (windpipe) – tube extending from the

larynx into the chest cavity

Divides into 2 smaller tubes, called bronchi.

Supported by cartilage rings that prevent the trachea

from collapsing.

Mucus traps foreign particles like dust.

Cilia propel this material back into the nose and throat to

be expelled by

coughing or sneezing.

Lower Respiratory Tract

Bronchi are supported by rings of cartilage.

Branch into smaller tubes

forming the bronchiole tree.

The smallest branches are

called the bronchioles.

Bronchiole tree terminates with the alveolar ducts, which

lead into tiny chambers, or air sacs, called alveoli

where gas exchange

takes place.

Alveoli are

surrounded by

pulmonary

capillaries which

aid in gas exchange.

Alveoli

Oxygen in the alveoli is exchanged with carbon dioxide in blood by diffusion (from an area of high concentration to low concentration).

Lungs

The lungs contain the bronchi, bronchioles, and alveoli.

They are protected by the ribs, sternum, and spine. This space is known as the thoracic cavity.

The base of each lung lies in contact with the diaphragm (a large, dome-shaped muscle).

Lungs

Contained within the

pleura, 2 membranous

sacs which surround the

lungs.

Very close together – only

very thin fluid, interpleural

fluid, separates them.

Mechanics of Breathing

Ordinarily, breathing movements are involuntary.

the body needs oxygen.

Breathing involves two

movements:

inhalation and

exhalation.

Breathing

Breathing uses two muscular structures to control air

pressure in the lungs:

Intercostal muscles: located beneath the ribs.

Diaphragm: muscle layer below the lungs.

They work together to move air into and out of the

lungs.

Inhalation

Ribs move upward and

outward.

Diaphragm moves

downward.

Volume is increased.

The lungs expand,

pressure is decreased.

Air enters lungs to

equalize pressure.

Exhalation

Ribs move inward and

downward.

Diaphragm moves

upward.

Volume decreases.

Pressure of the lungs

increases.

Air is forced out of the

lungs.

Lung Capacity

Vital capacity the maximum amount of air a person

can forcibly exhale after the largest possible inhalation

of air.

Tidal Volume: amount of air inhaled or exhaled during

normal breathing.

Spirometer

a device that assesses how well your lungs work by

measuring how much air you inhale, how much you

exhale and how quickly you exhale.

In which of the following situations

would your breathing rate be the

highest?

a) When at rest

b) Mild physical activity

c) Sleep

d) Intense physical activity

Answer: d

Breathing and Homeostasis

The ability of the body to adjust and maintain the levels of

oxygen and carbon dioxide

Breathing and the Brain

Breathing is controlled by

the medulla oblongata in

brain, sending and receiving

electrical impulses via

neurons.

Neurons transmit electrical

impulses from the brain to the

muscles.

The brain tells the muscles it’s

time to move!

Chemoreceptors

Breathing rate is controlled by a negative feedback

mechanism via chemoreceptors in arteries.

Chemoreceptor: a receptor sensitive to stimulation by

chemical substances.

Arterial chemoreceptors

detect the level of carbon

dioxide and pH of the blood.

Increased Physical Activity

Muscles work harder so they must make energy faster.

CO2 builds up in the blood which makes the blood acidic (lactic

acid)

Arterial chemoreceptors detect the increased level of

CO2 and decreased pH of blood and notifies the brain.

Medulla oblongata tells respiratory

muscles to increase the breathing rate

to rid the body of excess CO2 and

provide the cells with fresh O2.

**Complete homeostasis flow chart.

Breathing is constantly occurring

It is only when our ability to breathe is compromised

that we notice its importance.

The quality of the external environment and personal

lifestyle choices can have an enormous impact on the

health of our lungs and entire bodies.

Respiratory Impairment

Disorders of the respiratory system can cause

significant impairment in our ability to breathe and

exchange oxygen for carbon dioxide.

More than 3 million Canadians of all ages cope with

serious respiratory diseases.

https://www.youtube.com/watch?v=u7OChdn7H_k

https://www.youtube.com/watch?v=sVrb3B5m99M

https://www.youtube.com/watch?v=6JCAyb3lDTo

https://www.youtube.com/watch?v=5XnjBa1VjcE

Respiratory Disorder Jigsaw

In groups, you will use the information in the textbook (p. 344-348) or on the internet to research a respiratory disorder

Groups will then split up so that each new group has one expert on each disorder

Share your information with your new group

Respiratory disorders/diseases: Lung cancer

Pneumonia

Asthma

Chronic Bronchitis

Emphysema

What should you include?

Name of the disease/disorder

Description

Causes

Symptoms

Treatments

Other interesting facts