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Respiratory System

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In the nose, the hairs and the cilia act as a screening device. ... The pharynx takes air from the nose to the larynx and takes food from the oral ... – PowerPoint PPT presentation

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Title: Respiratory System


1
Respiratory System
  • Dr. Philip L. Pokorski
  • Department of Biology
  • University of Michigan--Dearborn

2
The Respiratory System
  • The respiratory system works with the
    cardiovascular system to exchange gases between
    the air and blood (external respiration) and
    between blood and tissue fluids (internal
    respiration).
  • Inspiration and expiration move air in and out of
    the lungs during breathing.
  • Cellular respiration is the final destination
    where ATP is produced in cells.

3
The respiratory tract
4
The Respiratory Tract
  • Air is cleansed, warmed, and moistened as it
    passes the cilia and mucus in the nostrils and
    nasal cavity.
  • In the nose, the hairs and the cilia act as a
    screening device.
  • In the trachea, the cilia beat upward, carrying
    dust and mucus into the pharynx.
  • Exhaled air carries out heat and moisture.

5
The Nose
  • The two nasal cavities are divided by a septum.
  • They contain olfactory cells, receive tear ducts
    from eyes, and communicate with sinuses.
  • The nasal cavities empty into the nasopharynx.
  • Auditory tubes lead from the middle ears to the
    nasopharynx.

6
The path of air
7
The Pharynx
  • The pharynx (throat) is a passageway from the
    nasal cavities to oral cavities and to the
    larynx.
  • The pharynx contains the tonsils the respiratory
    tract assists the immune system in maintaining
    homeostasis.
  • The pharynx takes air from the nose to the larynx
    and takes food from the oral cavity to the
    esophagus.

8
The Larynx
  • The larynx is a cartilaginous structure lying
    between the pharynx and the trachea.
  • The larynx houses the vocal cords.
  • A flap of tissue called the epiglottis covers the
    glottis, an opening to the larynx.
  • In young men, rapid growth of the larynx and
    vocal cords changes the voice.

9
Placement of the vocal cords
10
The Trachea
  • The trachea, supported by C-shaped cartilaginous
    rings, is lined by ciliated cells, which sweep
    impurities up toward the pharynx.
  • Smoking destroys the cilia.
  • The trachea takes air to the bronchial tree.
  • Blockage of the trachea requires an operation
    called a tracheostomy to form an opening.

11
Cilia in the trachea
12
The Bronchial Tree
  • The trachea divides into right and left primary
    bronchi which lead into the right and left lungs.
  • The right and left primary bronchi divide into
    ever smaller bronchioles to conduct air to the
    alveoli.
  • An asthma attack occurs when smooth muscles in
    the bronchioles constrict and cause wheezing.

13
The Lungs
  • Lungs are paired, cone-shaped organs that lie on
    either side of the heart and within the thoracic
    cavity.
  • The right lung has three lobes, and the left lung
    has two lobes, allowing for the space occupied by
    the heart.
  • The lungs are bounded by the ribs and diaphragm.

14
The Alveoli
  • Alveoli are the tiny air sacs of the lungs made
    up of squamous epithelium and surrounded by blood
    capillaries.
  • Alveoli function in gas exchange, oxygen
    diffusing into the bloodstream and carbon dioxide
    diffusing out.
  • Infant respiratory distress syndrome occurs in
    premature infants where underdeveloped lungs lack
    surfactant (thin film of lipoprotein) and
    collapse.

15
Gas exchange in the lungs
16
Mechanism of Breathing
  • During breathing, air moves into the lungs during
    inspiration (inhalation) from the nose or mouth,
    then moves out again during expiration
    (exhalation).
  • A spirometer allows measurement of the components
    of air during breathing.

17
Inspiration
  • When we inhale (inspiration) impulses from the
    respiratory center in the medulla oblongata cause
    the rib cage to rise and the diaphragm to lower,
    causing the thoracic cavity to expand.
  • The negative pressure or partial vacuum in the
    alveoli causes the air to come in.
  • Changing amounts of blood of CO2 and H increase
    breathing rate.

18
Inspiration
19
Expiration
  • When we exhale (expiration), lack of impulses
    from the respiratory center allow the rib cage to
    lower and diaphragm to resume dome shape.
  • Expiration is passive, while inspiration is
    active.
  • The elastic recoil of the lungs causes
    expiration.
  • A deep breath causes alveoli to stretch stretch
    receptors then inhibit the respiratory center.

20
Expiration
21
Gas Exchanges in the Body
  • External Respiration
  • External respiration is the diffusion of CO2 from
    pulmonary capillaries into alveolar sacs and O2
    from alveolar sacs into pulmonary capillaries.

22
  • Most CO2 is carried as bicarbonate ions.
  • The enzyme carbonic anhydrase, in red blood
    cells, speeds up the conversion of bicarbonate
    and H to H2O and CO2 CO2 enters alveoli and is
    exhaled.
  • Hemoglobin (Hb) takes up oxygen from alveoli and
    becomes oxyhemoglobin (HbO2).

23
Internal Respiration
  • Internal respiration is the diffusion of O2 from
    systemic capillaries into tissues and CO2 from
    tissue fluid into systemic capillaries.
  • Oxyhemoglobin gives up O2, which diffuses out of
    the blood and into the tissues because the
    partial pressure of O2 of tissues fluid is lower
    than that of the blood.

24
  • After CO2 diffuses from tissue cells into the
    blood, it enters red blood cells where a small
    amount is taken up by hemoglobin, forming
    carbaminohemoglobin.

25
External and internal respiration
26
Respiration and Health
  • The presence of disease in the upper or lower
    respiratory tract means that homeostasis is
    threatened.
  • Upper Respiratory Tract Infections
  • These infections involve the nasal cavities,
    pharynx, or larynx.
  • Some infections, such as strep throat, can lead
    to systemic body infection.

27
Sites of upper respiratory infections
28
Sinusitis
  • Sinusitis is infection of the cranial sinuses
    within the facial skeleton that drain into nasal
    cavities.
  • It occurs when nasal congestion blocks the sinus
    openings and is relieved when drainage is
    restored.
  • Pain and tenderness over the lower forehead and
    cheeks, and toothache, accompany this condition.

29
Otitis Media
  • Otitis media is bacterial infection of the middle
    ear.
  • Children suffer when a nasal infection spreads to
    the middle ear by way of the auditory tube and
    antibiotics are usually used to clear the
    infection.
  • Sometimes drainage tubes (called tympanostomy
    tubes) are inserted into the eardrums of children
    with recurrent infections.

30
  • Tonsillitis
  • Tonsillitis is infection of tonsils and recurrent
    infections that make breathing or swallowing
    difficult may be relieved by a tonsillectomy.
  • Laryngitis
  • Laryngitis is an infection of the larynx and
    usually results in a loss of voice.
  • Persistent hoarseness is a warning sign of cancer.

31
Lower Respiratory Tract Disorders
  • Lower respiratory infections include
  • 1) acute bronchitis, an infection of primary and
    secondary bronchi
  • 2) pneumonia involving a bacterial or viral
    infection of the lungs and
  • 3) pulmonary tuberculosis (infection caused by
    tubercle bacillus).

32
Restrictive Pulmonary Disorders
  • In restrictive pulmonary disorders, vital
    capacity is reduced because the lungs have lost
    their elasticity due to inhaled particles such as
    silica, coal dust, or asbestos.
  • Fibrous connective tissue builds in the lungs in
    pulmonary fibrosis, caused by exposure to inhaled
    particles, including those of fiberglass.

33
Obstructive Pulmonary Disorders
  • In obstructive pulmonary disorders, air does not
    flow freely in the airways, and inhalation and
    exhalation are difficult.
  • Chronic bronchitis with inflamed airways,
    emphysema where alveolar walls break down, and
    asthma with constricted bronchioles obstruct the
    airways and tend to get progressively worse or
    recur.

34
Lower respiratory tract disorders
35
Lung Cancer
  • Lung cancer follows this sequence of events
    thickening of airway cells, loss of cilia on the
    lining, cells with atypical nuclei, tumor
    development, and finally metastasis.
  • Removal of a lobe or lung, called pneumonectomy,
    may remove the cancer.
  • Smoking, whether active or passive, is a major
    cause of lung cancer.

36
Normal lung versus cancerous lung
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