RESPIRATORY SYSTEM Objective (E 3.1) – To learn the names of the organs of the upper respiratory system. To learn the function of each of these organs. To learn why humans need to exchange gases with their surrounding environment.

All humans exchange gases with their surroundings 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.

Today .. The beginning of the respiratory system… (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).

ORGANS OF THE RESPIRATORY SYSTEM 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: Warms air - Moistens air 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

Pharynx (throat) 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.

Larynx (voice box) 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)

Trachea 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

Trachea (windpipe) 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… 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 Learn names of organs of lower respiratory system Explain how gases are exchanged between environment and cell 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

Bronchiole Passages Right and Left Bronchus Bronchioles

Right and Left Bronchus Location 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

Lung (two lungs) 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

Lung (cont’d) 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.

Lung (cont’d) Function To allow for exchange of gases between the alveoli and their surrounding capillaries  

Alveoli of the Lungs 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

Alveoli (cont’d) 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). blood blood vessel alveolus air

Just a quick reminder about diffusion... 8Bd Just a quick reminder about diffusion... 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. 33

Alveoli (cont’d) 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?