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HUBS1404 > Respiratory P1 > Flashcards

Respiratory P1 Flashcards

1
Q

What is included in the upper respiratory tract?

A
  • Nose and nasal cavity
  • Pharynx
  • Larynx
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2
Q

What is included in the lower respiratory tract?

A
  • Trachea (windpipe)
  • Bronchial tubes
  • alveoli.
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3
Q

What are the characteristics of the nose and nasal cavity?

A
  • The external nose is constructed from bone and hyaline cartilage
    -It is lined with a mucus membrane
  • Divided internally by the nasal septum
  • Two openings are known as the external nares or nostrils
  • Olfactory receptors are located in the olfactory epithelium in the
    roof of the nose/nasal cavity
    ▫ Permit the reception of odourants
    Serves the following functions:
    ▫ Warms air
    ▫ Prevents dehydration
    ▫ Covered with mucus membrane
    and traps particles
    ▫ Cilia propel particles towards the
    pharynx where they can be
    swallowed
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4
Q

What is the characteristics of the pharynx?

A
  • Posterior to the nasal cavity and extends to the larynx
  • Three regions
    ▫ Nasopharynx
    ▫ Oropharynx
    ▫ Laryngopharynx
  • Contains the openings of the auditory tubes
    ▫ Also known as pharyngotympanic tubes or eustachian tubes
    ▫ Linked to the middle ear and equalises air pressure
     You can feel this as ‘popping’ when rapidly changing altitude
    Constructed of skeletal muscle
  • Circular and longitudinal
    ▫ Contraction involved in swallowing (deglutition)
  • Lined with mucus membrane
  • Contains the tonsils (palatine and lingual)
    ▫ Patches of lymphatic tissue similar to lymph nodes
    ▫ Play a role in immunity
    ▫ Subject to inflammation (tonsilitis), especially common in children
    and young adults
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5
Q

What is the characteristics of the larynx?

A
  • Connects the pharynx with the trachea
  • Constructed from 9 sections of cartilage
  • Contains the vocal folds for speech
  • Also contains the epiglottis
    ▫ Leaf-shaped elastic cartilage
    ▫ Closes off the glottis
    ▫ Prevents food or fluid from entering the trachea during swallowing
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6
Q

What is the characteristics of the trachea?

A
  • Tubular windpipe extending from the larynx to the two primary
    bronchial tubes
    ▫ Around the level of the 5th thoracic vertebra (T5)
  • Constructed from 4 layers:
  • Mucosa
    ▫ Inner-most layer
    ▫ Pseudostratified ciliated epithelium
    ▫ Mucus traps particles and is propelled by the cilia to be swallowed
    Submucosa
    ▫ Mostly areolar (loose) connective tissue
    ▫ Also contains mucus-secreting glands and their ducts
  • Hyaline cartilage
    ▫ 16-20 incomplete cartilage rings
    ▫ Open portion faces posteriorly towards the oesophagus – ends
    connected by trachealis muscle
  • Adventitia
    ▫ Connective tissue outer layer
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7
Q

What are the characteristics of the bronchial tubes?

A

The trachea divides into the two primary bronchi
* Each primary bronchus feeds air into and out of either the left or
right lung
* Lined with pseudostratified ciliated epithelia
* Also has incomplete cartilage rings
* Lower internal ridge where the right and left
bronchi originate is known as the carina
▫ Very sensitive and triggers cough reflex
* Primary bronchi divide into secondary or lobar bronchi
▫ Each secondary bronchus feeds a single lobe of the lung
* These further divide into tertiary or segmental bronchi
* More divisions into smaller bronchioles
* Smallest bronchioles known as terminal bronchi
* Branching of bronchial tubes know as the bronchial tree

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8
Q

What are the characteristics of the lungs?

A
  • Paired organs that sit inside the thoracic cavity
  • Surround the heart
  • The left and right lung reside in separate double-walled structures
    called pleural membranes
    ▫ Parietal pleura line the inside of the thoracic cavity
    ▫ Visceral pleura cover the lungs
  • Small space between these layers known as the pleural cavity
    ▫ Contains lubricating fluid to allow smooth inflation and deflation of
    the lungs
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9
Q

What are the characteristics of the alveoli?

A
  • Terminal bronchioles represent the end of the conducting zone of
    the lung
    ▫ Structures that carry air into and out of the lung
  • Each terminal bronchus gives rise to multiple respiratory
    bronchioles
    ▫ This is the start of the respiratory zone of the lung
  • Clusters of inter-connected hollow spheres called alveoli extend
    from an alveolar duct that is contiguous with each respiratory
    bronchus
  • Each alveolus is covered in pulmonary
    capillaries
    ▫ For gas exchange
  • Also covered in elastic fibres
    ▫ Stretch during inspiration
    ▫ Recoil to aid exhalation
  • Macrophages are present on the inner
    surface
    ▫ No cilia or mucus for self-cleaning
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10
Q

What is pulmonary ventilation?

A

The respiratory system constantly delivering oxygen-rich atmospheric air to the alveoli and expelling carbon-dioxide rich are from the alveoli to the atmosphere.
The movement of air into and out of our lungs is dependant on
different air pressures
▫ Atmospheric air pressure and pressures inside our lungs
* Air movement follows Boyle’s law
* Boyle’s law is concerned with the association of the pressure and
volume of a gas
▫ Pressure is inversely proportional to volume
* A simple bicycle pump uses the same principle
▫ Air enters the tyre once the pressure is high enough in the pump
cylinder

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11
Q

What is Boyle’s Law?

A

P1V1 = P2V2
* The main premise of Boyle’s law is:
▫ If the volume of a gas is increased, its pressure reduces
▫ If the volume of a gas is reduced, its pressure increases
* Our lungs reside in our thoracic cavity
▫ Encased in the pleural membrane
* Our respiratory muscles make our lungs into a type of pump
▫ If we increase their volume, the air pressure reduces
▫ If we reduce their volume, the air pressure increases
To inflate our lungs with external air, we must reduce the air
pressure within them
▫ Known as intrapulmonary or alveolar pressure
* To achieve this, we increase the lung volume
* Once alveolar air pressure is lower than atmospheric pressure, air
flows into our lungs
* To exhale we must increase alveolar air pressure by reducing the
lung volume
* Air is expelled from our lungs once alveolar air pressure is greater
than atmospheric air pressure

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12
Q

What are the jobs of the diaphragm, external intercostals, internal intercostals, abdominals, obliques, scalenes and sternocleidomastoid?

A

To increase and decrease the lung volume.

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13
Q

What muscles are used for inhalation?

A
  • Diaphragm
    ▫ Dome-shaped muscle forms the lower section of the thoracic cavity
    ▫ Flattens around 1 cm during quiet breathing
    ▫ Can flatten up to 10 cm during strenuous breathing
    ▫ Contraction contributes ≈ 75% of inhaled air
  • External intercostals
    ▫ Raise and widen the rib cage
    ▫ Contribute ≈ 25% of inhaled air
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14
Q

What is residual volume?

A

▫ Not all air expelled from lungs
▫ Volume of air remaining in lungs after forced expiration

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15
Q

What is tidal volume?

A

▫ Resting volume of air inhaled and exhaled
▫ Represents air moved in one breath

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16
Q

What is inspiratory reserve volume?

A

▫ Achieved during deep inhalation
▫ Excess volume inhaled beyond the normal tidal volume

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17
Q

What is expiratory reserve volume?

A

▫ Achieved during deep expiration
▫ Excess volume exhaled beyond the normal tidal volume

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18
Q

What is lung capacity?

A

Combinations of different lung volumes
▫ Often used to determine lung function

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19
Q

What is Inspiratory Capacity?

A
  • Inspiratory Capacity
    ▫ Inspiratory reserve volume + tidal volume
    ▫ Maximum volume of air inhaled from normal expiratory level
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20
Q

What is Functional Residual Capacity?

A
  • Functional Residual Capacity
    ▫ Expiratory reserve volume + residual volume
    ▫ Volume of air remaining in lungs after normal expiration
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21
Q

What is vital capacity?

A

▫ Inspiratory reserve volume + tidal volume + expiratory reserve
volume
▫ Maximum volume of air that can be inhaled/exhaled

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22
Q

What is total lung capacity?

A

▫ Vital capacity + residual volume

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23
Q

What controls breathing?

A

skeletal muscles and the respiratory centres.

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24
Q

What is the respiratory centre?

A
  • Two clusters of neurons are responsible for breathing
    ▫ Medullary respiration centre in the medulla oblongata
    ▫ Pontine respiratory group in the pons
  • Collectively known as the respiratory centre
  • Breathing rate and depth can be influenced by other regions of
    the CNS and PNS
    ▫ We can voluntarily hold our breath
    ▫ Stimulation is achieved by the hypothalamus and limbic system in
    response to emotions inducing laughing a or crying
    ▫ Receptors detect the concentrations of CO2, O2 and H+ and initiate
    changes to breathing
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25
Q

What is the atmospheric pressure at sea level?

A

760 mmHg (101.325 kPa or 1 atm).
Air pressure reduces as we increase altitude (less air being pulled down)
at 5,500 m, air pressure is ~ half that at sea level (380 mmHg)

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26
Q

Why is breathing important?

A
  • As aerobic organisms, we consume large quantities of oxygen
  • During ATP production, we produce carbon dioxide that must be eliminated
    ▫ Higher CO2 concentration increases H2CO3 formation and reduces blood pH
  • Therefore, the quantity of oxygen and carbon dioxide in the air we breathe is of importance
    ▫ We need oxygen
    ▫ We need to remove carbon dioxide
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27
Q

What is Dalton’s Law?

A

Total air pressure is the sum of the partial pressures of all gases in a mixture
* N2 - 78.6% PN2 = 597.4 mmHg
* O2 - 20.9% PO2 = 158.8 mmHg
* Ar - 0.093% PAr = 0.7 mmHg
* CO2 - 0.04% PCO2 = 0.3 mmHg
* H2O - 0.367% PH2O = 2.8 mmHg
* Total - 760 mmHg

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28
Q

What is Henry’s Law?

A

When a gas is in contact with a liquid, the dissolved gas is proportional to its partial pressure and solubility.
* A high partial pressure and solubility will increase the amount of gas dissolved in solution
* A low partial pressure and solubility will cause a decrease in gas dissolved in solution

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29
Q

What are the Partial Pressures of atmospheric air in the Respiratory system?

A

▫ PO2 = 159 mmHg
▫ PCO2 = 0.3 mmHg

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30
Q

What is the partial pressures of alveolar air in the respiratory system?

A

▫ PO2 = 104 mmHg
▫ PCO2 = 40 mmHg

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31
Q

How much oxygen is in plasma?

A

1.5% as it has poor solubility in water.

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32
Q

How much oxygen binds to haemoglobin in RBCs?

A

98.5%, each haemoglobin molecule has 4 haem units and each one binds to one O2 molecule, when an O2 molecule has bound to a haemoglobin it is known as oxyhaemoglobin.

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33
Q

What factors affect the oxyhaemoglobin saturation?

A

O2 binding to haemoglobin is easily reversable
* Haemoglobin that is fully converted to oxyhaemoglobin is said to be fully saturated
* Oxyhaemoglobin saturation is dependant on the PO2
* We can plot the relationship between PO2 and oxyhaemoglobin saturation
▫ Oxygen-haemoglobin dissociation curve
- Higher Hb-O2 affinity (left shift), lower CO2, higher pH, lower temp.
- Reduced Hb-O2 affinity(right shift), higher CO2, lower pH and higher temp.
* Acidity
▫ Binding of oxygen to haemoglobin decreases with acidity – Bohr effect
▫ H+ increase causes oxygen to dissociate from haemoglobin
 This effect is advantageous in tissues with a high H+ concentration as it increases oxygen unloading
* Carbon dioxide partial pressure
▫ Increased PCO2 decreases O2 binding
▫ CO2 binds to haemoglobin forming carbaminohaemoglobin
* Temperature
▫ Increased heat reduces oxygen binding to haemoglobin

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34
Q

How is Carbon Dioxide transported through the blood?

A
  • Bicarbonate ions – HCO3-
    ▫ Accounts for around 70% of CO2 transport
    ▫ Present in plasma and produced by carbonic anhydrase (CA)
     CO2 + H2O CA H+ + HCO3-
    ▫ Reaction reverse in pulmonary capillaries
     CO2 exhaled
  • Carbamino compounds
    ▫ CO2 binds to amino groups of amino acids
    ▫ Accounts for 23% of CO2 transport
    ▫ Haemoglobin is the predominant protein in blood
    ▫ CO2 binds to form carbaminohaemoglobin
     Hb + CO2 Hb-CO2
    ▫ Promoted by high PCO2
  • Dissolved CO2
    ▫ Simply dissolved in plasma (7%)
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35
Q

What does ventilated mean?

A

the flow of air into the alveolus

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36
Q

What does Perfused mean?

A

The blood flow through the pulmonary capillaries.

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37
Q

Is all alveoli ventilated equally in inhalation?

A

No, alveoli at the base of the lungs receive more air

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38
Q

What part of the lungs receive the least amount of air?

A

The apex (Top) of the lungs receive the least amount of air. ~ 50% difference.

39
Q

What is the respiratory zone of the lungs?

A
  • Respiratory bronchioles
  • Alveolar ducts
  • Alveolar sacs
  • Alveoli
  • The alveolar duct controls the
    flow of air to the alveoli
40
Q

What do we use to find the difference in perfusion?

A

Perfusion is also greater at the base of the lung
* Again, gravity results in more blood flowing in the lower sections
of the lungs
* We use the ratio of ventilation to perfusion to determine how
equally-matched they are
▫ V/Q
 V = ventilation
 Q = perfusion

41
Q

What is the V/Q ratio in an apex of the lung in a healthy person?

A

2.1 because of greater ventilation

42
Q

What is the V/Q ratio in the middle of the lung in a healthy person?

A

1, because ventilation matches perfusion.

43
Q

What is the V/Q ratio in the base of the lung in a healthy person?

A

0.3, this is because of greater perfusion.

44
Q

Is the volume of blood pumped through the systemic circuit and the pulmonary circuit the same?

A

Yes.
However, the dynamics are different

45
Q

How does the systemic circuit pump blood?

A
  • Systemic circuit
    ▫ High-pressure system
    ▫ Vascular resistance regulates blood flow
46
Q

How does the pulmonary circuit pump blood?

A
  • Pulmonary circuit
    ▫ Low-pressure system
    ▫ Parallel pathways for blood to flow
    ▫ Low vascular resistance – 1/10th of systemic
47
Q

What are some restrictive pulmonary disorders?

A

Pulmonary fibrosis, pulmonary oedema.

48
Q

What are some obstructive pulmonary disorders?

A

Asthma, chronic bronchitis, emphysema.

49
Q

What are masses in the lungs?

A

Tumours or scar tissue.

50
Q

What is pulmonary fibrosis?

A
  • Scarring of lung tissue
    ▫ Normal tissue replaced by fibrotic
    tissue
  • Reduces lung compliance
  • Inhibits oxygen diffusion
  • Often caused by autoimmune
    disorders
  • Causes also include:
    ▫ Tuberculosis
    ▫ Asbestosis and silicosis
51
Q

What is pulmonary oedema?

A

Most commonly caused by heart problems
* Congestive heart failure
▫ Left ventricle and/or left AV valve
dysfunction
▫ Blood backs up on left side of heart as it
cannot be pumped effectively into systemic
circuit
▫ Increased pressure in pulmonary blood
vessels forces fluid out
▫ Fluid collects in alveoli
* Hypertensive crisis
▫ Increased afterload inhibits left ventricular
stroke volume
* Pulmonary capillary membrane damage
▫ Makes capillaries more permeable to fluids
▫ Can be caused by infection such as
pneumonia
▫ Also irritants such as toxic gases from
industrial welding, sulphur dioxide and
chlorine gas

52
Q

What is asthma?

A
  • Asthma is associated with chronic inflammation of the bronchial
    tubes
  • Characterised by bronchospasms, increased mucus secretion and airway obstruction
  • Caused by genetic and environmental factors
  • Environmental factors include:
    ▫ Allergens
    ▫ Pollutants
    ▫ Drugs including aspirin
    ▫ Sulphates used as preservatives in wine, beer etc
53
Q

What is chronic bronchitis?

A

Chronic bronchitis is an inflammatory condition resulting in:
▫ Excess thick mucus secretion
▫ Loss of ciliary function
▫ Increased risk of infection

54
Q

What is emphysema?

A
  • Causes the loss of alveolar walls
  • Results in:
    ▫ Large air spaces that remain full of air after exhalation
    ▫ This prevents new, oxygen-rich air from entering lungs
55
Q

What is the normal pH range for blood?

A

7.35 -7.45

56
Q

What causes acidosis?

A

-pH Below 7.35

57
Q

What are the different types of acidosis?

A
  • Respiratory acidosis.
  • Metabolic acidosis
58
Q

What causes alkalosis?

A
  • pH above 7.45
59
Q

What are the different types of alkalosis?

A
  • Respiratory alkalosis
  • Metabolic Alkalosis
60
Q

How is blood pH maintained?

A
  • The three mechanisms used are:
  • Buffering systems (quickest)
    ▫ Rapid but do not remove H+ from the body
  • Removal of carbon dioxide (minutes)
    ▫ Increasing pulmonary ventilation rate and depth to remove excess CO2
  • Excretion of H+ by the kidneys (slowest)
    ▫ Only mechanism that eliminates H+ from the body
61
Q

How does the body respond to exercise?

A
  • Exercise is a regular activity that places a major demand on the
    body
    ▫ Increased O2 consumption and CO2 production
  • To met these demands:
    ▫ Pulmonary ventilation and perfusion are increased
    ▫ Vasodilation occurs in working muscles to increase blood flow
    ▫ PO2 and PCO2 drive diffusion in both external and internal respiration
    VENTILATION
  • Anticipation of exercise stimulates increased breathing rate and
    depth
    ▫ Driven by the limbic system
  • Breathing pattern then dependant on exercise intensity
    ▫ Via feedback from chemoreceptors measuring PO2, PCO2 and H+
    PERFUSION
    Increased pulmonary perfusion
    ▫ Cardiac output increases in both the systemic and pulmonary circuits
    – same stroke volume in each ventricle
  • Pulmonary perfusion rises
  • Increases the O2 diffusing capacity 3x
     Due to pulmonary capillaries being fully perfused
62
Q

What are the changes in epithelium in the bronchial tubes?

A
  • Primary, secondary and tertiary bronchi
    ▫ Pseudostratified ciliated columnar epithelium with goblet (mucus
    secreting) cells
  • Large bronchioles
    ▫ Simple ciliated with some goblet cells
  • Smaller bronchioles
    ▫ Simple ciliated with few goblet cells
  • Terminal bronchioles
    ▫ Simple cuboidal
63
Q

What are the changes in cartilage and smooth muscle in the bronchial tubes?

A

As bronchial tubes get smaller, plates of cartilage replace
incomplete rings
* Smooth muscle content increases as cartilage decreases
▫ Smooth muscle present in spiral bands
▫ Helps keep bronchial tubes open
▫ Influenced by catecholamines
 Epinephrine and norepinephrine relaxes this muscle and causes
bronchodilation
▫ Muscle spasms may close off bronchial tubes
 This occurs during an asthma attack

64
Q

How are alveoli structured?

A

Alveoli are constructed using simple squamous epithelial cells
(known as type I cells)
* The alveolar wall and capillary wall form the respiratory
membrane
▫ Gases must diffuse across this
▫ Very thin – 0.5 μm to aid speed of diffusion (copy paper is 100 μm)
* Also contain type II cells (septal cells)
▫ Small cuboidal cells with microvilli
▫ These secrete alveolar fluid - surfactant to reduce surface tension

65
Q

How many alveoli are in the lungs?

A

~ 300 million

66
Q

What are the factors that affect pulmonary ventilation?

A

Alveolar surface tension, Lung compliance, Airway resistance

67
Q

How does alveolar surface tension affect pulmonary ventilation?

A

▫ Water molecules are bound by hydrogen bonds
▫ Stronger attraction to each other than to gas molecules in the air
▫ This surface tension pulls the alveoli slightly inwards
 Reduces their volume
▫ Must be overcome to expand the volume of each alveolus
▫ Surfactant secreted by Type II cells helps reduce this

68
Q

How does Lung compliance affect pulmonary ventilation?

A

▫ Describes the ease of lung expansion
 Caused by the difference between intrapleural and alveolar pressures
▫ High compliance = easy to expand per unit change of pressure
▫ Low compliance = difficult to expand per unit change of pressure
* Low compliance may be caused by:
▫ Scarring of alveoli usually caused by diseases such as tuberculosis
▫ Increased fluid in lung tissue – pulmonary oedema
▫ Deficiency of surfactant – increased surface tension

69
Q

How does airway resistance affect pulmonary ventilation?

A

▫ Resistance caused by walls of the bronchial
tubes
▫ Normally dilated during inhalation and
constrict a little during exhalation
▫ Also modulated by the ANS
▫ Any narrowing or obstruction to airways
increases resistance
▫ Seen in asthma and chronic bronchitis

70
Q

How many breaths does an average adult take a minute?

A

12 (500 ml of air per breath), volume can increase by 50% during peak exercise over resting values.
- volume increases per breath
- Number of breaths/min increases.

71
Q

What is the mixture of gases in the air?

A

▫ N2 - 78.6%
▫ O2 - 20.9%
▫ Ar - 0.093%
▫ CO2 - 0.04%
▫ H2O & others 0.367%

72
Q

Where is the partial pressure of oxygen higher? Why?

A

The Alveoli, this is because solutes diffuse from a higher concentration to a lower concentration (higher gradients = faster diffusion rates), therefore if the PP of oxygen is higher in the alveoli, it ensures the oxygen diffuses into the blood.

73
Q

Where is the partial pressure of Carbon Dioxide higher? Why?

A

In pulmonary capillary blood, this is because solutes diffuse from a higher concentration to a lower concentration (higher gradients = faster diffusion rates), therefore if the PP of CO2 is higher in the PCB the CO2 will diffuse out of the blood and into our lung.

74
Q

Why are there differences in the partial pressure of the respiratory system?

A

▫ Small tidal volume used in quiet breathing
▫ O2 constantly diffusing into blood
▫ CO2 high in residual and expiratory reserve volumes

75
Q

What are the partial pressures of alveolar air in external respiration?

A
  • PO2 = 104 mmHg
  • PCO2 = 40 mmHg
76
Q

What are the partial pressures of pulmonary capillary blood (oxygen poor) in external respiration?

A
  • PO2 = 40 mmHg
  • PCO2 = 45 mmHg
77
Q

What are the partial pressures of oxygen-rich blood (systemic capillary) in internal respiration?

A
  • PO2 = 100 mmHg
  • PCO2 = 40 mmHg
78
Q

What are the partial pressures of tissue cell in internal respiration?

A
  • PO2 = 40 mmHg
  • PCO2 = 45 mmHg
79
Q

Why is there a difference in alveolar ventilation?

A
  • The weight of fluid in the plural cavity is greatest at the base of
    the lung
    ▫ Due to the force of gravity
  • This increases the intrapleural pressure
    ▫ Pressure within the pleural cavity
  • The alveoli here are less expanded and have a higher compliance
  • Therefore, they can be filled with more air
80
Q

What is the mean pressures of the pulmonary circulation?
mmHg

A
  • Pulmonary artery = 15
  • Beginning of capillary = 12
  • End of capillary = 9
  • Left atrium = 8
  • Net driving pressure = 15 - 8 = 7
81
Q

What is the mean pressures of the Systemic circulation?
mmHg

A
  • Aorta = 95
  • Beginning of capillary = 35
  • End of capillary = 15
  • Right atrium = 2
  • Net driving pressure = 95 - 2 = 93
82
Q

To obtain the maximum gas exchange, how do we modulate perfusion and air flow in the lungs?

A
  • Low alveolar oxygen content
    ▫ Pulmonary vasoconstriction
    ▫ Limits blood flow to these alveoli
    ▫ Blood shunted to alveoli with higher oxygen content
    ▫ Bronchioles dilate to flow more air to increase oxygen delivery
  • High alveolar carbon dioxide content
    ▫ Bronchioles dilate to flow more air to increase carbon dioxide and
    oxygen diffusion
83
Q

How does the air flow through conducting airways?

A
  • Airflow follows similar principles to blood flow
  • Pressure difference drives flow
  • Resistance from airway walls
  • 10% reduction in airway radius =
    ▫ 52% increase in resistance
    ▫ 35% decrease in airflow
    Flow = pressure gradient/resistance
84
Q

What are the modulators of airway diameter?

A

Smooth muscle in airways contains receptors to:
▫ Neurotransmitters
▫ Hormones
* Muscarinic receptors bind acetylcholine
▫ Causes bronchoconstriction
* Β adrenergic receptors bind adrenaline (epinephrine)
▫ Causes bronchodilation
▫ Also bind sympathomimetics:
 Albuterol (salbutamol/Ventolin) and salmetrol
 Used by asthmatics to cause bronchodilation

85
Q

What are the effects of acidosis?

A
  • results in depression of the central nervous system.
  • caused by loss of synaptic transmission.
  • pH below 7 leads to disorientation.
  • Possible coma and death.
86
Q

What are the effects of alkalosis?

A
  • Alkalosis causes overexcitement of the central and peripheral nervous systems.
  • Nervousness
  • Muscle spasms and convulsions
  • Death
87
Q

Name the characteristics of respiratory acidosis and the causes

A

▫ Result of high CO2 concentrations above 45 mmHg
▫ ↑ CO2 forms more H2CO3 = ↑ H+
▫ Failure to maintain adequate alveolar ventilation and/or perfusion to remove CO2
* Causes include:
▫ Lung diseases
▫ Damage to respiratory muscles or innervation
▫ Drugs that may reduce ventilation rate

88
Q

Name the characteristics of metabolic acidosis and the causes

A

▫ Too much acid is produced by working cells
▫ Failure of the kidneys to remove H+ from blood
* Causes include:
▫ Kidney disease
▫ Diabetic acidosis – ketoacidosis
▫ Lactic acidosis – ineffective oxidative metabolism
▫ Loss of bicarbonate ions due to severe diarrhea
▫ Poisoning – aspirin, methanol

89
Q

Name the characteristics of respiratory alkalosis and the causes

A
  • Respiratory alkalosis
    ▫ Blood PCO2 below 35 mmHg
    ▫ Results in an increase in pH
     ↓ in H2CO3 formation and subsequent H+ concentration
  • Causes include:
    ▫ Hyperventilation – removal of too much CO2 by the respiratory system
     Anxiety, high altitude oxygen deficiency etc.
90
Q

Name the characteristics of metabolic alkalosis and the causes

A
  • Metabolic alkalosis
    ▫ High systemic blood concentration of HCO3-
    ▫ Binds more H+ and reduces acidity
  • Causes include:
    ▫ High intake of alkaline drugs e.g. sodium bicarbonate
    ▫ Extreme vomiting – loss of gastric acids (HCL)
91
Q

How does the carbonic acid - bicarbonate buffering system work?

A

The primary buffering system in the body is the carbonic acid-
bicarbonate buffer system
* H2CO3 - carbonic acid
▫ Acts as a weak acid
* HCO3- - bicarbonate ion
▫ Acts as a weak base
▫ Kidneys can synthesise and resorb HCO3-
* Can adjust both an excess or shortage of H+
If there is a drop in pH (↑ H+), bicarbonate ions are used to bind free H+
H+ + HCO3- → H2CO3 → H2O + CO2
* CO2 can then be removed during exhalation
* If there is an increase in pH (↓H+), carbonic acid (H2CO3) can add H+
H2CO3 → H+ + HCO3-
Carbonic acid → hydrogen ion → Bicarbonate ion

92
Q

What cardiac output do you see during exercise in which the intensity is continuously increased?

A

Increases in heart rate, O2 consumption, Stroke Volume and Cardiac Output.

93
Q

How does age affect the respiratory system?

A
  • Increasing age has a negative effect on the respiratory system
  • Elasticity is lost from the airways down to the alveoli
  • Alveoli become ‘baggy’
  • Chest wall also becomes more rigid
  • Results in a loss of vital capacity of up to 35%
  • Loss of bronchial tube ciliary function and reduction in alveolar
    macrophages increase risk of infection and disease

HUBS1404 (10 decks)

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