RESPIRATORY SYSTEM

Objective (E 3.1) –

1)To learn the names of the organs of the upper respiratory system.

2)To learn the function of each of these organs.

3)To learn why humans need to exchange gases with their surrounding environment.

• All humans exchange gases with their surroundings. Warm-blooded animals have a high oxygen demand.

• RECALL: cellular respiration (in the mitochondria)

sugar + 6 O2 32 ATP + 6H2O + 6 CO2

(usable energy)

• The respiratory system is used to exchange the by-product of cellular respiration (carbon dioxide) for the oxygen that is necessary to produce ATP. Since we can’t store carbon dioxide or oxygen we need to continuously exchange gases.

• (Handout diagram)

• Key Terms:

Ventilation (inspiration and expiration)Nasal cavities pharynx (throat) epiglottis

larynx (vocal cords) glottis trachea

• The organs of the respiratory system are structured to breathe air in and breathe air out.

• Inspiration (inhalation) is the process of taking air (O2) in.

• Expiration (exhalation) expels carbon dioxide (CO2) and water vapors (H2O) from the body.

The respiratory system works with the cardiovascular system to accomplish respiration which consists of the following: •1. Breathing - inhaling and exhaling of air.•2. External respiration - exchange of O2 and CO2 gases, between the air sacs in the lungs and the blood in the pulmonary capillaries. •3. Internal respiration - exchange of O2 and CO2 between blood in the systemic capillaries and body cells •4. Cellular respiration - use of O2 by cells to combine with glucose to produce CO2, water and ATP (the energy currency of cells).

• The respiratory system consists of a series of tubes that deliver air to the air sacs in the lungs. These passageways can be divided into two main groups:

• Organs of the upper respiratory tract– Nose, nasal cavities - Pharynx– Larynx - Trachea

• Organs of the lower respiratory tract– Trachea – Lung

• Bronchi• Bronchioles• Alveoli

Air through the upper respiratory tract

1) Air enters the body through nostrils or mouth

2) Air passes through the pharynx

3) Air passes over the epiglottis, through the larynx (voice box)

4) Air travels down the trachea (made of cartilage rings to keep it open)

Nasal Cavity

• Entrance to the respiratory system

Function:

1)Warms air -

2)Moistens air

3)Cleans air

1) Warming Air - capillaries that line the nasal cavity are filled with warm blood. As air passes by, the heat is transferred to the air.

2) Moistens Air - mucus membranes that line the nasal cavity are filled with fluid. Air passing by, absorbs this moisture.

• 3) Cleans Air - Coarse hairs in the nose act as a filter keeping out large dust particles. Mucus produced by mucus secreting cells, help trap dust particles

• A passageway for both food and air, thus it is common to both the respiratory system and the digestive system.  

Description• Connects the nasal and oral cavities with the

larynx

Function– the passage of air into the larynx – the passage of food into the esophagus.

Description – entrance to the trachea• a "trap door" called the epiglottis covers the

trachea during swallowing and prevents food from entering the trachea causing choking

• "Adam's Apple",(protects vocal cords) can be felt on the neck.

Structure• formed of cartilage and ligaments. Cartilage is a

flexible, rubbery support tissue

• Vocal cords are two thin sheets of elastic ligaments that stretch across the glottis (the opening of the trachea).

• The production of sound results from air passing through the vocal cords and causing them to vibrate

• Functions – Passageway for air from pharynx to trachea– Production of sound

• Pitch is controlled by changing the tension on the vocal cords and varying the size of the glottis:– High pitched sounds =

high tension, glottis is narrower (faster vibrations)

– Low pitched sounds = low tension, glottis is wider (slower vibrations)

Structure• Has ‘C’ shaped rings of cartilage in its wall for

support. • Open part of the ‘C’ faces the esophagus allowing

for expansion of the esophagus and reducing friction between the two structures.

• Smooth muscle and connective tissue also help support the trachea.

• Cilia help sweep mucus containing trapped dust and pathogens, up and out towards the pharynx

Function

• The continuation of the passage of air from larynx to lungs

• The entrance to the trachea is called the glottis.

• Fill in the table with the location, composition and function of the respiratory structures we learned about today.

H/W

What do we need oxygen?

Page 289 # 1,2

Why is the pharynx a unique structure?

The Lower Respiratory Tract

Objectives

1)Learn names of organs of lower respiratory system

2)Explain how gases are exchanged between environment and cell

3)Explain the process of

inhalation and exhalation

2) Lower Tract

• From the trachea, air passes into the right and left bronchus, then into bronchioles and finally alveoli

1. Right and Left Bronchus

2. Bronchioles

Right and Left BronchusLocation • The first two branches off of the trachea.• left bronchus enters the left lung and the

right bronchus enters the right lung

 

Function

• They continue the passage of air into the bronchioles

Bronchioles

Location• Bronchioles branch like a tree and spread

throughout the chambers of the lungs, eventually terminating in tiny air sacs called alveoli.

Function• There are a lot of them. This helps to

increase the surface area available to deliver air to the alveoli

Location

• The two lungs lie in the chest cavity

• They are protected by bones of the ribs, sternum and spine

• The base of the lungs rests on the diaphragm

Structure• Contains lobes• Each lobe is divided into many lobules which are

formed of millions of air sacs called alveoli. Alveoli are served by bronchioles that bring air into them and are surrounded by pulmonary capillaries

• Lung tissue is pinkish-gray in colour and resembles an expandable sponge.

Function

• To allow for exchange of gases between the alveoli and their surrounding capillaries

 

 Location

• Found within the lobules of the lungs

• There are approximately 300 million of them and thus they make up the majority of the lung tissue

blood

blood vessel alveolus

air

blood

blood vessel alveolus

air

Structure

• Alveolus join in groups like a bunch of grapes These groups are surrounded by a network of capillaries.

• Gases must diffuse across the alveolar and capillary wall (alveolar-capillary membrane or respiratory membrane).

Alveoli have thin walls to allow the gases to diffuse easily into the blood.Diffusion is when particles move from a place where there are lots of them to a place where there are less of them.Oxygen diffuses into red blood cells in the capillaries. (Carried on the r.b.c by ________)Carbon dioxide diffuses from the blood plasma back into the alveoli.

8Bd

Function

• Functional unit of the lung.

• Gas exchange will occur between the walls of the alveoli and the surrounding pulmonary capillaries.

blood

blood vessel alveolus

air

blood in capillaries air in alveoli

deoxy blood high CO2 low CO2

oxy blood high O2

Inhalation• Ribs move out and diaphragm moves down• Volume of lungs increases therefore air comes

in (pressure inside lungs is lower than pressure outside lungs, air moves along the concentration gradient)

Exhalation• Ribs move in and diaphragm moves up• Volume of lungs decreases, and air is forced out

(pressure inside the lunges is higher than pressure outside)

Muscles to Pull Air in/Push it Out

• The ribs and the diaphragm work together to bring air in and push it out

Gases move from an area of high pressure to an area of low pressure.

Conditions of the Respiratory System

• Emphysema is a chronic condition that results when the alveoli rupture, distend or clump together. The damage is permanent

• Pneumonia may be caused by either a virus or bacteria, and results in the bronchi and alveoli filling with thick fluid

• Tuberculosis is caused by bacteria that permanently destroy the lung tissue

• Asthma – a disease of the bronchi and bronchioles. The smooth muscle of the bronchioles constricts, narrowing the diameter of the tubes and thus decreasing air passage. This results in an individual wheezing or gasping for air.

• Bronchitis is the inflammation of the mucus membrane of the bronchi causing narrowing of the passageway.

Demonstrating Inhalation

• You will construct a model lung to demonstrate how air enters the lungs when we breath in.

• Follow up questions (read Breathing Movements – page 287-288)

1) What role do the diaphragm and ribs play in inhalation and exhalation?

2) What role does pressure and volume play in ventilation?