The Respiratory System Lab 10 rev 4/11

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The Respiratory SystemLab 10 rev 4/11

• The primary function of the respiratory system is
  to deliver oxygen (O2) to and remove carbon
  dioxide (CO2) from the blood.
• The respiratory system also plays a role in
  maintaining the blood pH (acid-base balance).

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The Respiratory SystemLab 10

• Anatomy of the Respiratory System
• Upper Respiratory Tract (see picture on page 130)
• nose, nasal cavities, sinuses and pharynx
  (throat)
• The nose, nasal cavities and sinuses provide a
  large area of highly vascularized tissues which
  warm, filter and add moisture to air.
• As air comes into contact with the warm, moist
  tissue of the nasal passages, it is warmed and
  moistened. The sinuses also add moisture to the
  air.

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The Respiratory SystemLab 10

• The pharynx (throat) connects the nasal cavity
  and mouth to the larynx (voice box).
• union of the nasal passages and the pharynx and
  the make it possible to breathe through your
  mouth.
• Other structures which enter or are located in
  the pharynx are
• 2 tear ducts which carry fluid away from the eyes
  (this is why excess tears also make your nose
  runny)
• the esophagus the passage for food

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The Respiratory SystemLab 10

• The 2 Eustachian tubes that drain the middle ear
  and equalize air pressure between the middle ear
  and outside air.
• Food
• Below the throat, the air passage crosses in
  front of the esophagus. This makes it possible
  for food or liquids to be accidentally sucked
  into the air passages and can cause us to cough
  or choke. These actions attempt to clear the food
  or liquid.

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The Respiratory SystemLab 10

• Epiglottis-a flap of cartilage located in the
  back of the throat.
• During swallowing, the epiglottis forms a tight
  seal over the trachea so food cant go down it.
• The Uvula-a flap of tissue in the back of the
  mouth that hangs from the roof of your mouth.
• This closes the upper air passages so food does
  not come out your nose. (This is also the part of
  the body that causes snoring when air passes over
  it.)

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The Respiratory SystemLab 10

• The lower respiratory tract includes
• the larynx, trachea, 2 bronchi, 2 lungs
  (including the bronchioles and alveoli)
• the larynx or voice box is below the epiglottis
  and pharynx and is protected by the thyroid
  cartilage (nicknamed the Adams apple).
• Functions of the larynx
• maintains an open airway
• route food and air into their appropriate tubes
• assist in the production of sound

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The Respiratory SystemLab 10

• The vocal cords consist of 2 folds of connective
  tissue that extend across the airway. The
  opening of this airway is called the glottis.
• Vocal cords are supported by ligaments. Sound is
  produced as we expel air past them causing the
  cords to vibrate.

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The Respiratory SystemLab 10

• The trachea (or windpipe) is a tube below the
  larynx. It is about 4 1/2 inches long, is
  composed of C-shaped rings of cartilage (to
  ensure that it stays open), and carries air to
  the bronchi (see picture page 132).
• The trachea branches into airways which are
  called the right and left bronchi. These further
  subdivide into smaller and smaller bronchi.

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The Respiratory SystemLab 10

• The walls of the bronchi contain fibrous
  connective tissue and smooth muscle reinforced
  with cartilage. As the branches get smaller, the
  amount of cartilage declines. When they have no
  cartilage, their name changes into bronchioles.
• Surrounding the bronchi are the lungs. These
  fill the thoracic cavity and extend from the
  clavicles to the diaphragm (a thin sheet of
  muscle).

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The Respiratory SystemLab 10

• Bronchioles lead to alveoli which are the air
  sacs of the lungs. Alveoli are composed of a
  single layer of flat, simple squamous cells and
  this is where gas exchange takes place.

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The Respiratory SystemLab 10

• Breathing
• Involves repetitive cycles of getting air into
  and out of the lungs.
• This requires muscular effort.
• Since the lungs themselves do not have any
  skeletal muscle tissue, expansion and contraction
  occurs because the surrounding bones and muscles
  expand the size of the chest cavity.

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The Respiratory SystemLab 10

• Inspiration
• As the diaphragm contracts and flattens, the
  external intercostal muscles contract and lift
  the ribcage. This causes a pressure drop in the
  thoracic cavity.
• The scalene and sternocleidomastoid (SCM) muscles
  also contract to help expand the thoracic cavity
  space.
• As the volume (space) in the thoracic cavity
  increases, air rushes in to fill this space.

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• Other things that help inspiration
• The lungs and chest cavity are surrounded by a
  membrane called pleura. There is fluid between
  the layers of the pleura so the lungs can stretch
  and contract with minimum friction.
• There is also a partial vacuum between the 2
  pleural layers. This causes the lungs to stick
  to the chest wall as it expands.
• Alveolar surfactant, a chemical within the lungs,
  decreases the surface tension so the lung tissue
  doesnt stick to itself.

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The Respiratory SystemLab 10

• Expiration
• The diaphragm relaxes and intra-abdominal
  pressure pushes the diaphragm up. The internal
  intercostal muscles and gravity help to drop the
  ribcage and thoracic cavity back to its smaller
  size. This increases pressure within the lungs
  and forces the air out of them.

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The Respiratory SystemLab 10

• Respiratory Volumes
• Tidal volume is the amount of air an individual
  normally inhales and exhales.
• Our body's normal breathing strategy is to
  ventilate the air sacs and also keep a minimal
  residual volume in the lungs. This allows us to
  keep some air for the blood passing through the
  lungs between breaths. This air is referred to
  as dead space volume.

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The Respiratory SystemLab 10

• The amount of air that can be forcibly inhaled
  after a normal inspiration (tidal volume) is
  called inspiratory reserve volume.
• The amount of air that can be forcibly exhaled
  after a normal expiration (tidal volume) is
  called expiratory reserve volume.
• The vital capacity is the maximal volume that you
  can forcibly exhale after a maximal inhalation.
• After you forcibly exhale, there is always some
  air left in the lungs. This is called the
  residual volume.

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The Respiratory SystemLab 10

• These lung capacities are measured with a
  spirometer, which you will be using in one of the
  activities.
• Gases are transported from the lungs to the body
  primarily by hemoglobin. They can also be
  dissolved in the plasma. In plasma, carbon
  dioxide dissolves and becomes carbonic acid or
  bicarbonate. These are the chemicals that enable
  the experiment on page 136 to work.
• For more detailed explanation look in your
  textbook.

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The Respiratory System Lab 10 REMINDER, page 1

• 1. Learn anatomy of the respiratory system on the
  models (no pigs or slides).
• 2. On page 129, perform the activity of studying
  the Upper Respiratory System.
• 3. Do both activities on page 131 study and know
  the location of the nasal conchae, epiglottis,
  thyroid cartilage, cricoid cartilage, pharynx,
  vocal cords and trachea.
• 4. Learn everything listed in figure 14.4 (page
  132) except the esophagus.

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The Respiratory System Lab 10 REMINDER, page 2

• 5. Perform activities on pages 131-137 with the
  following exception on page 138
• DO NOT DO Deglutition Apnea

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REMINDER, page 3

• 6. When using the wet spirometer,
• use the cardboard mouthpiece.
• Push the arrow on the top all the way to the
  right
• There is a white tub which floars on the water
  and you will push this up as you blow into the
  spirometer