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Biology 11

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Title: Biology 11


1
The Respiratory System
  • Biology 11
  • A. Allen
  • Cow lungs ?

2
Activate your prior knowledge!
  • What is respiration?
  • What organs/structures make up the respiratory
    system?
  • Draw a sketch of a human respiratory system.
  • What are the lungs for?
  • How does air get in and out your lungs?

3
Interesting facts
  • There are 150 million alveoli in each lung. Total
    surface area in both lung 40 m2 (1/2 tennis
    court). diameter of alveoli 0.1 0.2 mm.
  • Laryngitis is the swelling of the vocal cords in
    the larynx (voice box). Can cause your voice to
    sound hoarse. Some smokers have permanent
    hoarseness from chronic inflammation.
  • You automatically cough when food heads down your
    trachea. Coughing brings the food back up to the
    mouth.
  • Your epiglottis closes off the trachea as you
    swallow. Why?
  • Tuberculosis (TB) is caused by bacteria that
    destroys the air sacs in the lungs.
  • An estimated 1.7 million people died from TB in
    2009. The highest number of deaths was in Africa.

4
Interesting facts
  • you lose about ½ litre of water a day through
    breathing
  • The stuff that comes out of your mouth when you
    cough travels at about 160 km/hr.
  • One acre of trees produces enough oxygen to keep
    18 people alive for one year.
  • Cigarettes and cigarette smoke contain over 4,000
    chemicals, including 43 known to cause cancer. 
  • Every cigarette shortens your life by 14
    minutes.
  • Lizards cant breathe when they are running.
    Their breathing depends on the muscles between
    their ribs. These muscles must be used during
    running.  
  • Some animals such as certain frogs can breathe
    through their skin.

5
Importance of Gas Exchange
  • Composition of Atmosphere
  • ? 78 Nitrogen
  • ? 21 Oxygen
  • ? 0.03 Carbon Dioxide
  •  
  • Cells obtain energy by breaking down sugars. O2
    is the required.
  • Humans need oxygen to survive (250 mL/min)
  • Humans may live several days without water, weeks
    without food, only minutes without oxygen.

6
Human Respiratory System
7
Components of the Upper Respiratory Tract
  • Passageway for respiration
  • Receptors for smell
  • Nose lined with mucus, cilia and long hairs to
    filter incoming air.
  • Moistens and warms incoming air
  • Resonating chambers for voice

8
Components of the Lower Respiratory Tract
  • Larynx maintains an open airway, routes food and
    air appropriately, assists in sound production
  • Trachea transports air to and from lungs
  • Bronchi branch into lungs
  • Bronchioles small branches that lead to alveoli
    fr bronchi
  • Lungs transport air to alveoli for gas exchange
  • Diaphragm essential for breathing
  • contraction ? ? chest volume ?
  • ? pressure ? inspiration!

9
Summary of Air Movement
  • air from environment
  • into nasal cavity/mouth (hair and mucus filter
    particles -boogers!)air get moistened and
    warmed.
  • into pharynx
  • pharynx branches into trachea (mucus and cilia
    sweeping hair-like structures- filter air in
    trachea ..debris goes to pharnyxswallow it!
  • pharynx branches into 2 bronchi (one in each
    lung)
  • bronchi branch off into bronchioles (smaller)
  • bronchioles end in air sacs, made of alveoli, the
    site of gas exchange between blood and air!

Respiration
10
THE RESPIRATORY SYSTEM
  • Like the nasal passages, the trachea is lined
    with a cilia a mucous membrane for trapping
    foreign particles. The cilia constantly move to
    sweep debris up towards the pharynxspit it out
    or swallow!
  • The smoke from one cigarette will paralyze the
    cilia for 20 minutes and increase the production
    of mucus in the air passages resulting in
    smokers cough.
  • The trachea is about 12 centimeters long and
    about 2.5 centimeters wide and is lined by rings
    of cartilage which help maintain its shape and
    prevent it from collapsing when air is exhaled.

11
Boogers!
  • When dust, dirt, germs, and pollen get stuck
    inside the nose, the mucus surrounds it and tiny
    hairs inside the nose called cilia help move the
    mucus and the trapped stuff toward the front of
    the nose or the back of the throat. When the
    mucus, dirt and other debris dry and clump
    together, you're left with a booger!

12
THE RESPIRATORY SYSTEM
  • As with the blood vessels, as the air passages
    subdivide into more branches, their diameter
    decreases.
  • As the bronchial tubes divide and subdivide,
    their diameter decreases, their walls become
    thinner and they eventually lose their cartilage
    rings.
  • Finally, they form a network of tiny tubes called
    BRONCHIOLES.

13
THE RESPIRATORY SYSTEM
  • The bronchioles end in little air sacs called
    ALVEOLI.
  • Alveoli are surrounded by capillaries and are the
    site of gas exchange (oxygen and carbon dioxide)
    with the circulatory system.
  • Inhaled oxygen diffuses into the blood and binds
    with hemoglobin - carbon dioxide diffuses from
    the blood into the alveoli and is exhaled.

14
Oxygen Transport
  • Oxygen enters the blood stream from the lungs.
  • Oxygen itself is not very soluble. There is only
    0.3 mL of oxygen/100 mL of blood.
  • After 0.3 mL of oxygen enters 100 mL of blood, no
    more oxygen will diffuse into the blood.
  • Hemoglobin acts to disguise the oxygen.
  • Hemoglobin and oxygen bond together to form
    oxyhemoglobin.
  • When this happens, more oxygen can come into the
    blood.
  • (When oxygen is formed as oxyhemoglobin, it does
    not count towards the 0.3mL.)
  • When oxygen is disguised as hemoglobin, blood
    can transfer 20 mL of oxygen for every 100 mL of
    blood.
  • Oxygen does not split from hemoglobin until
    partial pressure drops to 5.3kPa. This happens
    in the capillaries next to the body tissues.

hmcgraw-hill.movement_of oxygen_and_carbon_dioxide

alveolar_pressure_changes_McGraw Hill
15
Carbon Dioxide Transport
  • Carbon Dioxide is 20 X more stable than Oxygen.
  • In the blood
  • 9 is in the plasma (liquid portion of blood).
  • 27 is combined with hemoglobin to form
    carbaminohemoglobin.
  • 64 combines with water from plasma to form
    carbonic acid. (H2CO3)
  • The enzyme carbonic anhydrase causes this
    reaction to increase by 250x.
  • When carbon dioxide is in the form of carbonic
    acid it is in disguise.
  • This saves room for more carbon dioxide to enter
    the blood.
  • Remember carbon dioxide travels from areas of
    greater partial pressure to areas of lesser
    partial pressure .
  • If it seems like there is less carbon dioxide in
    the blood, more will leave the tissues.
  • If some of the carbon dioxide is in disguise in
    the blood stream, then more carbon dioxide will
    leave the tissues.

16
Mechanics of Breathing
  • Inspiration (breathing in)
  • requires chest cavity to increase in volume to
    create low pressure.
  • Accomplished when
  • diaphragm contracts and moves down (abdominal
    breathing)
  • External intercostal muscles contract (only
    during forced inspiration)

17
Mechanics of Breathing
  • Expiration (breathing out)
  • requires chest cavity to decrease in volume to
    create high pressure.
  • Accomplished when
  • diaphragm relaxes and moves up (abdominal organs
    help with thisthey were squished during
    inspiration)
  • Internal intercostal muscles contract (only
    during forced expiration)
  • Diaphragm youtube
  • 3D breathing youtube

Gas exchange youtube
18
Mechanics of Breathing
  • When the external intercostals contract, the ribs
    swing up and out like bucket handles. This
    increases the chest volume to create the low
    pressure required for air to enter the lungs.

19
Measurement of Lung Function
  • Tidal volume volume of air inhaled and exhaled
    in a single breath
  • Residual Volume the air that remains in the
    airways and does not participate in gas exchange
  • Vital capacity the maximal volume that can be
    exhaled after maximal inhalation
  • Inspiratory reserve volume the amount of air
    that can be inhaled beyond the tidal volume
  • Expiratory reserve volume the amount of air that
    can be forcibly exhaled beyond the tidal volume
  • Residual volume the amount of air remaining in
    the lungs, even after a forceful maximal
    expiration

20
Regulation of Breathing
Figure 10.13
21
Breathing rate is monitored by Blood CO2 levels
- increase as more CO2 is produced as a waste
product Blood O2 levels - decrease as O2 is used
up in respiration to produce ATP Rate is more
sensitive to changes in CO2 levels. In the blood,
carbon dioxide dissolves into hydrogen and
bicarbonate ions (HCO3-) CO2 H2O ? H
HCO3- Fall of CO2 Equation shifts to the
left More CO2 is produced by removing hydrogen
ions This increases blood pH (more
alkaline) Excess CO2 (exercise) Equation shifts
to the right More CO2 dissolves in blood to
produce more hydrogen ions This reduces blood pH
(more acidic) Chemoreceptors Located in the
aorta (aortic bodies) and common carotid arteries
(carotid bodies) Monitor pH and CO2 levels Send
impulses to the medulla Aortic bodies monitor CO2
and O2 levels, and BP but NOT pH! Carotid bodies
monitors CO2 and O2 levels, and pH Exercise
Increases CO2 / blood becomes more
acidic Chemoreceptors detect low pH and stimulate
respiratory centres in the medulla
oblongata. Respiratory centres send more impulses
to diaphragm and intercostals muscles Increases
breathing rate and depth
22
Disorders of Respiratory System
  • Reduced air flow asthma, emphysema, bronchitis
  • Infections pneumonia, tuberculosis, botulism
  • Lung cancer
  • Congestive heart failure
  • Cystic fibrosis

23
Gas Exchange Transport A Passive Process
  • Gases diffuse according to their partial
    pressures
  • External respiration gases exchanged between air
    and blood
  • Internal respiration gases exchanged with tissue
    fluids
  • Oxygen transport bound to hemoglobin in red
    blood cells or dissolved in blood plasma
  • Carbon dioxide transport dissolved in blood
    plasma, bound to hemoglobin, or in the form of
    plasma bicarbonate

24
Regulation of Breathing Nervous System
Involvement
  • Respiratory center in the medulla oblongata
    establishes basic breathing pattern
  • Chemical receptors monitor carbon dioxide,
    hydrogen ions, and oxygen levels
  • Medulla sensitive to hydrogen ions in
    cerebrospinal fluid resulting from carbon dioxide
    in blood
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