Respiratory System

1
Chapter 23

• Respiratory System

2
Respiration

• Ventilation Movement of air into out of lungs
• External respiration Gas exchange b/n air in
  lungs blood
• Transport of O2 and CO2 in the blood
• Internal respiration Gas exchange b/n the blood
  tissues

3
Respiratory System Functions

• Gas exchange O2 enters blood CO2 leaves
• Regulation of blood pH Altered by changing blood
  CO2 levels
• Voice production Movement of air past vocal
  folds makes sound speech
• Olfaction Smell occurs when airborne molecules
  drawn into nasal cavity
• Protection Against microorganisms by preventing
  entry removing them

4
Respiratory System Divisions

• Upper tract
• Nose, pharynx associated structures
• Lower tract
• Larynx, trachea, bronchi, lungs

5
Nose and Pharynx

• Nose
• External nose
• Nasal cavity
• Functions
• Passageway for air
• Cilia cleans the air
• Mucous humidifies (moistens air inhaled)
• Capillaries warm air
• Smell
• Along with paranasal sinuses are resonating
  chambers for speech

• Pharynx
• Common opening for digestive respiratory
  systems
• Three regions
• Nasopharynx
• Oropharynx
• Laryngopharynx

6
Larynx

• Functions
• Maintain an open passageway for air movement
• Epiglottis vestibular folds prevent swallowed
  material from moving into larynx (can move to
  cover trachea)
• Vocal folds are primary source of sound
  production

7
Structure of Larynx

• AKA voice box
• Thyroid cartilage AKA Adams apple
• Protects vocal cords
• Moves when you swallow
• Epiglottis closes off larynx so food liquid
  travel down the esophagus

8
Voice Production

• False vocal cords assist w/ hold breath
• True vocal cords
• Space between them called glottis
• Vibration produces sound
• In combination with tongue, mouth, nose to
  produce words

9
Concept Check

• Name the functions of the respiratory system.
• -Gas exchange regulation of blood pH olfaction
  protection
• How is the respiratory system divided? Name the
  parts of each.
• -Upper (Nose, Pharynx, Assoc. Structures)
• -Lower (Larynx, Trachea, Bronchi, Lungs)
• Name the accessory structures of the nose, and
  describe their function.
• -Cilia (cleans air) Mucus (moistens air),
  Capillaries (warms air)
• The larynx is also known as the
• -Voice Box

10
Trachea

• Windpipe
• Divides to form
• Primary bronchi
• Carina Cough reflex

Insert Fig 23.5 all but b
11
Organs of Respiration

• Trachea
• AKA windpipe
• Smooth muscle supported by C-shaped rings of
  cartilage
• food can travel down esophagus easier
• Passageway for air from larynx to bronchi
• Lined w/ cilia mucous

12
Tracheobronchial Tree

• Conducting zone
• Trachea to terminal bronchioles which is ciliated
  for removal of debris
• Passageway for air movement
• Cartilage holds tube system open smooth muscle
  controls tube diameter
• Respiratory zone
• Respiratory bronchioles to alveoli
• Site for gas exchange

13
Organs of Respiration

• Bronchi
• Left right primary bronchi branch off trachea
• Lined w/ cilia
• Supported by cartilage

14
Bronchial Tree
15
Bronchioles and Alveoli
16
Alveolus and Respiratory Membrane
17
Lungs

• Two lungs Principal organs of respiration
• Right lung Three lobes
• Left lung Two lobes

18
Organs of Respiration

• Alveoli
• Extremely thin-walled sacs covered w/ capillaries
  
• CO2 O2 move by diffusion across the respiratory
  membrane
• About 300 million alveoli in two lungs
• Size of a tennis court

19
Organs of Respiration

• Alveoli
• Surfactant lines the alveoli to aid diffusion
  decrease surface tension
• To prevent the alveoli from collapsing sticking
  shut

20
Pleura

• Pleural fluid produced by pleural membranes
• Acts as lubricant
• Helps hold parietal visceral pleural membranes
  together

21
Concept Check

• The trachea is also known as
• -Windpipe
• How is the trachea structured why?
• -C-Shaped rings of cartilage (allows passage of
  food to move easily)
• Describe the bronchial tree.

22
Ventilation

• Movement of air into and out of lungs
• Air moves from area of higher pressure to area of
  lower pressure (AKA Diffusion)
• Pressure is inversely related to volume

23
Inspiration

• Breathing in
• When pressure in the lungs is less than the air
  pressure in the atmosphere
• Diaphragm will contract and lower, increasing
  the size of the thoracic cage

24
Inspiration

• Increased volume will decrease the pressure the
  lungs will expand

25
Expiration

• Breathing out
• When the pressure inside the lungs is greater
  than the pressure in the atmosphere
• Diaphragm relaxes and rises decreases the size
  of the thoracic cage

26
Expiration

• Decreased volume will increase pressure lungs
  will decrease and push air out

27
Internal Respiration

• Exchange of O2 and CO2 between tissue capillaries
  and tissue cells
• CO2 moves from high concentration in cells to low
  concentration in blood

28
External Respiration

• Conversion of deoxygenated blood to oxygenated
  blood
• Aided by thin membranes
• Large surface area
• Narrow capillaries

29
Concept Check

1. What is the diffusion?
2. What is the difference between inspiration and
   expiration?
3. What happens to the diaphragm? Be specific.

30
Changing Alveolar Volume

• Lung recoil
• Causes alveoli to collapse resulting from
• Elastic recoil and surface tension
• Surfactant Reduces tendency of lungs to collapse
• Pleural pressure
• Negative pressure can cause alveoli to expand
• Pneumothorax is an opening between pleural cavity
  air that causes a loss of pleural pressure

31
Compliance

• Measure of the ease with which lungs thorax
  expand
• The greater the compliance, the easier it is for
  a change in pressure to cause expansion
• A lower-than-normal compliance means the lungs
  and thorax are harder to expand
• Conditions that decrease compliance
• Pulmonary fibrosis
• Pulmonary edema
• Respiratory distress syndrome

32
Pulmonary Volumes

• Tidal volume
• Volume of air inspired or expired during a normal
  inspiration or expiration
• Inspiratory reserve volume
• Amount of air inspired forcefully after
  inspiration of normal tidal volume
• Expiratory reserve volume
• Amount of air forcefully expired after expiration
  of normal tidal volume
• Residual volume
• Volume of air remaining in respiratory passages
  and lungs after the most forceful expiration

33
Pulmonary Capacities

• Inspiratory capacity
• Tidal volume plus inspiratory reserve volume
• Functional residual capacity
• Expiratory reserve volume plus the residual
  volume
• Vital capacity
• Sum of inspiratory reserve volume, tidal volume,
  and expiratory reserve volume
• Total lung capacity
• Sum of inspiratory and expiratory reserve volumes
  plus the tidal volume and residual volume

34
Spirometer and Lung Volumes/Capacities
35
Minute and Alveolar Ventilation

• Minute ventilation Total amount of air moved
  into out of respiratory system per minute
• Respiratory rate or frequency Number of breaths
  taken per minute
• Anatomic dead space Part of respiratory system
  where gas exchange does not take place
• Alveolar ventilation How much air per minute
  enters the parts of the respiratory system in
  which gas exchange takes place

36
Physical Principles of Gas Exchange

• Partial pressure
• The pressure exerted by each type of gas in a
  mixture
• Diffusion of gases through liquids
• Concentration of a gas in a liquid is determined
  by its partial pressure and its solubility
  coefficient

37
Physical Principles of Gas Exchange

• Diffusion of gases through the respiratory
  membrane
• Depends on membranes thickness, the diffusion
  coefficient of gas, surface areas of membrane,
  partial pressure of gases in alveoli and blood
• Relationship between ventilation and pulmonary
  capillary flow
• Increased ventilation or increased pulmonary
  capillary blood flow increases gas exchange
• Physiologic shunt is deoxygenated blood returning
  from lungs

38
Oxygen Carbon Dioxide Diffusion Gradients

• Oxygen
• Moves from alveoli into blood. Blood is almost
  completely saturated with oxygen when it leaves
  the capillary
• C02 in blood decreases because of mixing with
  deoxygenated blood
• Oxygen moves from tissue capillaries into the
  tissues

• Carbon dioxide
• Moves from tissues into tissue capillaries
• Moves from pulmonary capillaries into the alveoli

39
Hemoglobin and Oxygen Transport

• Oxygen is transported by hemoglobin (98.5) and
  is dissolved in plasma (1.5)

40
Transport of Carbon Dioxide

• Carbon dioxide is transported as bicarbonate ions
  (70) in combination with blood proteins (23)
  and in solution with plasma (7)

41
Herring-Breuer Reflex

• Limits the degree of inspiration and prevents
  overinflation of the lungs
• Infants
• Reflex plays a role in regulating basic rhythm of
  breathing and preventing overinflation of lungs
• Adults
• Reflex important only when tidal volume large as
  in exercise

42
Ventilation in Exercise

• Ventilation increases abruptly
• At onset of exercise
• Movement of limbs has strong influence
• Learned component
• Decreases slightly
• Ventilation increases gradually
• After immediate increase, gradual increase occurs
  (4-6 minutes)
• Anaerobic threshold is highest level of exercise
  without causing significant change in blood pH
• If exceeded, lactic acid produced by skeletal
  muscles

43
Disorders

• Asthma spasms of smooth muscle in the
  bronchioles
• Lung cancer
• Constant irritation produces excess mucous and
  puts unnecessary stress on the bronchi
• Alveoli destroyed by WBCs acting on the
  irritation
• Structural cells disappear and cancer cells take
  over

44
Disorders

• Emphysema alveolar walls lose their elasticity
• Some alveoli merge and reduce volume
• Have to work voluntarily to exhale
• Bronchitis inflammation of the bronchi
• Creates site for infection and increases mucous

45
Disorders

• Pneumonia infection or inflammation of the
  alveoli
• Tuberculosis (TB) bacterial infection that
  destroys lung tissue and is replaced by
  non-elastic connective tissue

46
Disorders

• Respiratory Distress Syndrome (RDS)
• Lack of surfactant makes breathing difficult
• Alveoli are sticking together
• Occurs in infants
• Pulmonary Embolism
• blood clot obstructs circulation to lung tissue
  tissue dies

47
Disorders

• Respiratory Failure
• Not enough O2 to maintain metabolism
• Cannot eliminate enough CO2
• Caused by
• Drugs
• Stroke
• CO poisoning
• shock

48
Disorders

• Colds and Flu viral infections
• Sudden Infant Death Syndrome (SIDS)
• Crib death
• Occurs between 1 week and 12 months
• Cause is unknown
• Baby stops breathing

49
Disorders

• Laryngitis vocal cords
• Pharyngitis sore throat
• Rhinitis lining of the nose

50
Effects of Aging

• Vital capacity and maximum minute ventilation
  decrease
• Residual volume and dead space increase
• Ability to remove mucus from respiratory
  passageways decreases
• Gas exchange across respiratory membrane is
  reduced