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BIOL1046 Human Biology II > Unit 7: The Respiratory System > Flashcards

Unit 7: The Respiratory System Flashcards

1
Q

What is respiration?

A

it is gas exchange (oxygen and carbon dioxide) between the atmosphere and body cells

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2
Q

What is ventilation?

A

The movement of air into and out of the lungs

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3
Q

What is inspiration (inhalation)?

A

Breathing in

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4
Q

What is expiration (exhalation)?

A

Breathing out

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5
Q

What is cellular respiration?

A

The use of oxygen by cells to make ATP

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6
Q

What are the functions of the respiratory system?

A

Air passageway
Site for exchange of oxygen and carbon dioxide
Detection of odours
Sounds production

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7
Q

What are the structural divisions of the respiratory system?

A

Upper respiratory tract
Lower respiratory tract

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8
Q

What structures are apart of the upper respiratory tract?

A

Nose, nasal cavity, pharynx, and larynx

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9
Q

What structures are apart of the lower respiratory tract?

A

Trachea, bronchi, bronchioles, alveolar ducts, and alveoli

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10
Q

What are the functional organizations of the respiratory system?

A

Conducting zone
Respiratory system

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11
Q

What does the conducting zone do?

A

Structures of the conducting zone transport air, nose to the terminal bronchioles

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12
Q

What does the respiratory zone do?

A

Structures of the respiratory zone participate in gas exchange, respiratory bronchioles, alveolar ducts and alveoli

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13
Q

What is mucosa?

A

mucous membrane (respiratory lining)

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14
Q

How is mucous secreted?

A

Mucus secretions are produced by goblet cells of the epithelial lining. It contains mucin protein and serve to trap dust, dirt, pollen and others. Almost 1 to 7 tablespoons of secretions are produced daily and contain defenses against microbes (lysozymes, defensins, and immunoglobulin A). It is often called sputum when coughed up with saliva and other trapped substances.

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15
Q

What are the functions of the nose?

A

Main conducting passageway for inhaled air
Filters dust and other particles out of the air (nose hair)
Warms and moistens air to facilitate diffusion across respiratory membranes
Acts as a resonance chamber for speech
Contains chemoreceptors (in superior nasal conchae) that give us our sense of smell

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16
Q

What is the structure of the nose?

A

The nose is formed by bone, hyaline cartilage, dense irregular connective tissue, and skin

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17
Q

The nasal cavity….

A

is from nostrils and choanae

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18
Q

What are the different structures the nose consists of?

A

Nostrils (nares)
Nasal septum
Nasal conchae (turbinate bones)
Choanae
Floor of the nose formed by palate

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19
Q

What are the nostrils (nares)?

A

flared opening of the nose consisting of skin

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20
Q

What is the nasal septum?

A

it divides the left and right sides

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21
Q

What are nasal conchae (turbinate bones)?

A

It is three paired bony projections on lateral walls of the nasal cavity separated into superior, middle, and inferior. Their purpose is to produce turbulence in inhaled air. A portion of the nasal cavity is separated into different passages called a nasal meatus. Each meatus is immediately inferior to its corresponding concha.

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22
Q

What is the choanae (posterior nasal apertures)?

A

paired openings that lead to the pharynx

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23
Q

What is a nasal vestibule?

A

located just inside nostrils, lined by the skin and particle-trapping hairs called vibrissae

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24
Q

What is the olfactory region?

A

It is the superior part of the nasal cavity containing olfactory epithelium. Airborne molecules stimulate receptors for odour protection .

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25
Q

What the respiratory region?

A

It is lined by pseudostratified ciliated columnar epithelium and has a extensive vascular network. Nosebleeds are common due to large numbers of superficial vessels.

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26
Q

What are lacrimal ducts?

A

Theses drain lacrimal secretions from eye surfaces to nasal cavity

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27
Q

Describe how the nasal cavity conditions the air (warms, cleanses, and humidifies).

A

The air is warmed by extensive blood vessels and mucus traps dust, microbes, and foreign material. Cilia sweep mucous toward the pharynx to be swallowed. Moist environments humidify the air and air turbulence is created by conchae enhances all three processes.

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28
Q

What are paranasal sinuses?

A

These are spaces within skull bones, used to lighten the weight of the bone. They are named for the specific bone in which they are housed in and they are all connected by ducts to the nasal cavity. They are lined by pseudostratified ciliated columnar epithelium. Mucus is swept into the pharynx and swallowed (we swallow more than 1 L per day).

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29
Q

List the paranasal sinuses from superior to inferior.

A

Frontal sinuses
Ethmoidal sinuses (Sphenoidal sinuses posterior to ethmoidal sinuses)
Maxillary sinuses

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30
Q

What is the pharynx?

A

Funnel-shaped passageway posterior to nasal cavity, oral cavity, and larynx. Has lateral walls composed of skeletal muscles. It is separated into nasopharynx, oropharynx, and laryngopharynx.

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31
Q

What is the nasopharynx?

A

The nasopharynx is posterior to the nasal cavity and is used as an air passage only, not for food. The soft palate (uvula) elevates during swallowing to block food and drinks. It connects to the middle ear through auditory tube allowing for equalization of pressure on each side of lymphatic membrane. Tonsils are contained in this cavity which as a infection-fighting lymphatic tissue. The tubal tonsils are near auditory tube opening, pharyngeal tonsil is posterior to the nasopharynx wall (which are called adenoids when enlarged).

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32
Q

What is the oropharynx?

A

The oropharynx is posterior to the oral cavity and is used as a passageway for both food and air. It contains the palatine tonsils which are located on the lateral walls and the lingual tonsils at the base of the tongue.

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33
Q

What is the laryngopharynx?

A

It is posterior to the larynx and is used a passageway for food and air.

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34
Q

What are the functions of the larynx (voice box)?

A

Air passageway
Produces sound
Prevents ingested materials from entering respiratory tract
Assists in increasing pressure in abdominal cavity
Participates in sneeze and cough reflexes

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35
Q

How does the larynx produce sound?

A

The vocal cords vibrate during expiration

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36
Q

How does the larynx prevent ingested materials from entering respiratory tract?

A

The epiglottis covers superior opening during swallowing.

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37
Q

How does the larynx assist in increasing pressure in the abdominal cavity?

A

The valsalva maneuver which are vocal folds that close off rima glottidis (opening between the folds) and the contraction of abdominal muscles. Increased pressure facilitates urination, defecation, and childbirth.

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38
Q

How does the larynx participate in sneeze and cough reflexes?

A

Coughing helps remove irritants from nasal cavity or lower respiratory tract. The abdominal muscles contract increasing the thoracic pressure and the vocal cords are forcibly opened by the pressure. The explosive blast of exhaled air is a cough or a sneeze.

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39
Q

What are vocal ligaments?

A

They are composed primarily of avascular elastic connective tissue and are covered with mucosa to form the vocal folds (true vocal cords). Sound is produced when air passes between them.

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40
Q

What are extrinsic muscles?

A

Skeletal muscles that stabilize larynx and help it move during swallowing

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41
Q

What are intrinsic muscles?

A

Skeletal muscles located within the larynx that are involved in voice production and swallowing.

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42
Q

What is the trachea (windpipe)?

A

It is the first structure of the lower respiratory tract (structural division) and is an open tube connecting the larynx to the main bronchi.

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43
Q

Explain the gross anatomy of the trachea.

A

The trachea is anterior to the esophagus, and posterior to part of the sternum. It is about 13 cm long and 2.5 cm in diameter. It contains tracheal cartilages that support anterior and lateral walls that are C-shaped rings of hyaline cartilages and are used to ensure the trachea is always open and allow for accomodation for the esophagus when bulges of food pass through. Is also has a carnia which is an internal ridge at the inferior end of the trachea that contains many sensory receptors and it is what initiates the cough reflex when irritants are present.

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44
Q

Explain the respiration overview.

A
  1. Air containing oxygen is inhaled into the alveoli during inspiration
  2. Oxygen diffuses form alveoli into pulmonary capillaries
  3. Blood from lungs transports oxygen to systemic cells
  4. Oxygen diffuses from systemic capillaries into systemic cells
  5. Carbon dioxide diffuses from systemic cells into systemic capillaries
  6. Carbon dioxide is transported in blood from systemic cells to lungs
  7. Carbon dioxide diffuses from pulmonary capillaries into alveoli
  8. Air containing carbon dioxide is exhaled from alveoli into the atmosphere
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45
Q

Explain the impact of aging on the respiratory system.

A

Lung tissue eventually loses its ability to expand (compliance) with age due to a natural reduction in collagen formation and scar tissue formation (from diseases such as colds or pneumonia). It is also because of environmental factors like anthracosis from breathing polluted air or from smoking (or second-hand smoke).

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46
Q

Explain the development of the respiratory system.

A

The epithelial lining of the respiratory tract develops from the endoderm and smooth muscles, connective tissue develop from the mesoderm. Type II alveolar cells become active and surfactant beings to be produced around week 25 of development which is enough to breathe normally by about week 35.

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47
Q

What is Infant Respiratory Distress Syndrome (IRDS)?

A

It is when premature babies often need artificial surfactant and oxygen if surfactant has not yet developed.

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48
Q

Explain birth in regards to the respiratory system.

A

The lungs become active and gas exchange switches to lungs from the placenta. The normal respiration rate is 40-60 times per minute.

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49
Q

What is the bronchial tree?

A

It is a system of highly branched air passages that originates at the main bronchi, branches to more narrow tubes ending at terminal bronchioles.

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50
Q

Explain the structure of the primary bronchi.

A

The trachea is split into left and right main bronchus (primary bronchi) at the level of the sternal angle. Each bronchus enters a lung on its medial surface and the right bronchus is shorter, wider and more vertically oriented. The foreign particles are more likely to lodge there.

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51
Q

Explain the structure of secondary bronchi.

A

Each of the main bronchus branches into lobar bronchi (secondary bronchi) and each extends into a lobe of the lung. It is smaller in diameter than main bronchi.

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52
Q

Explain the structure of tertiary bronchi.

A

Lobar bronchi are further divided into segmental bronchi (tertiary bronchi) which are then divide into bronchioles (<1mm, with no cartilaginous rings). They are then further divided into terminal bronchioles (the last part of the conducting zone. Terminal bronchioles divides into respiratory bronchioles which is the first part of the respiratory zone.

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53
Q

What is bronchoconstriction?

A

It is smooth muscle contraction that narrows bronchiole diameter which causes less air through bronchial traa (less entry of potentially harmful substances).

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54
Q

What is bronchodilation?

A

It is smooth muscle relaxation increases bronchiole diameter and allows more air through the bronchial tree.

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55
Q

Explain the functionally of the respiratory zone.

A

Everything up to and including the bronchioles is part of the conducting zone (no gas exchange). The respiratory zone is where gas exchange can occur and it begins at the respiratory bronchioles.

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56
Q

Explain the structures of the respiratory zone.

A

The respiratory zone structures are microscopic. The respiratory bronchioles subdivide to alveolar ducts which lead to alveolar sacs, clusters of alveoli. The alveoli is saccular out pocketings.

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57
Q

Explain the epithelium of the respiratory zone.

A

The respiratory bronchioles are lined with simple cuboidal epithelium. The alveoli and alveolar ducts are lined by simple squamous and the thinnes facilitates gas exchange.

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58
Q

What is the alveoli?

A

Each lung contains 300 to 400 million alveoli and they are surrounded by pulmonary capillaries. They contain elastic fibres and are divided by interalveolar septum.

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59
Q

What are alveolar pores?

A

They are opening providing collateral ventilation

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60
Q

What are the 3 different cell types of the alveolar wall?

A

Alveolar type I cells
Alveolar type II cells
Alveolar macrophage

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61
Q

What are alveolar type I cells (squamous alveolar cells)?

A

These are the most common of the two cell types making up alveolar wall and cover 95% of alveolar surface area. They form the alveolar epithelium of the respiratory membrane.

62
Q

What are alveolar type II cells (septal cells)?

A

They secrete oily pulmonary surfactant and coats the insides of alveolus and opposes collapse during expiration.

63
Q

What are alveolar macrophages (dust cells)?

A

They are leukocytes that engulf microorganisms and are either fixed in alveolar wall or free to migrate.

64
Q

What is the respiratory membrane?

A

It is a thin barrier (0.5 microns*) that seperates the air in the alveoli and the blood in pulmonary capillaries. It consists of alveolar epithelium and its basement membrane, capillary epithelium and its basement membrane, and the basement membranes are fused together. Oxygen diffuses from the alveolus into the capillaries allow erythrocytes to become oxygenated. Carbon dioxide diffuses from blood to alveolus which is exhaled to the external environment.

65
Q

Where are the lungs located?

A

The lungs are in the thorax on either side of the mediastinum and they house the bronchial tree and all the respiratory portions of the respiratory system. Each of the lungs has a concial shape which a wide concave base on top of the diaphragm. The apex points superiorly just behind the clavicle.

66
Q

What are the different lung surfaces?

A

The costal surface is adjacent to the ribs, the mediastinal surface is adjacent to the mediastinum and the diaphragmatic surface is adjacent to the diaphragm.

67
Q

What is the hilum?

A

The hilum is the indented region on lung’s mediastinal side. The bronchi, pulmonary vessels, autonomic nerves, lymph vessels pass through it. These structures are collectively called the root of the lung.

68
Q

Explain the sizes of the lungs.

A

The right is larger and wider than the left lung and has three lobes divided by two fissures. The left lung is smaller than right due to heart’s position has two lobes divided by one fissure.

69
Q

What is Pleura?

A

It is serous membrane lining lung surfaces and thoracic wall. There is visceral pleura which adheres to lung and parietal pleura which lines internal thoracic walls, lateral surface of mediastinum, and the superior surface of the diaphragm. Each lung is enclosed in a separate visceral pleural membrane, this helps limit the spread of infections.

70
Q

What is the pleural cavity?

A

It is located between visceral and parietal serous membranes. When the lungs are inflated, it is considered a potential space. Visceral and parietal almost touching.

71
Q

What is serous fluid produced by serous membranes?

A

It covers the pleural cavity surface and it lubricates, allowing pleural surfaces to slide by easily. Each pleural cavity has <15 mL fluid and is drained continuously by lymph.

72
Q

What is a spirometer?

A

It measures respiratory volume and can be used to assess respiratory health. Standard values are available (e.g. for people of different ages).

73
Q

Tidal Volume

A

the amount of air inhaled or exhaled per breath during quiet breathing (about 500mL on average)

74
Q

Inspiratory Reserve Volume (IRV)

A

the amount of air that can be forcibly inhaled beyond the tidal volume

75
Q

Expiratory Reserve Volume (EVR)

A

The amount that can be forcibly exhaled beyond tidal volume

76
Q

Residual Volume

A

The amount of air left in lungs after the most forceful expiration

77
Q

Inspiratory Capacity (IC)

A

Tidal Volume + Inspiratory Reserve Volume

78
Q

Functional Residual Capacity (FRC)

A

The volume left in the lungs after a quiet expiration
Expiratory Reserve Volume + Residual Volume

79
Q

Vital Capacity

A

The total amount of air a person can exchange through forced breathing
Tidal Volume + Inspiratory and Expiratory Reserve Volume

80
Q

Total Lung Capacity (TLC)

A

Sum of all volumes, including residual volume
Maximum volume of air that the lungs can hold

81
Q

What is Anatomic Dead Space?

A

Conducting zone space, where no exchange of respiratory gases of about 150 mL

82
Q

What is physiologic dead space?

A

Normal anatomic dead space +any loss of alveoli
Some disorders decarese the number of alveoli participating in gas exchange due to damage to alveoli or changes in respiratory membrane.
Anatomic dead space = physiolgic dead space in healthy individual where loss of alveoli is minimal.

83
Q

What are the 4 respiratory processes of respiration?

A

Pulmonary Ventilation
Pulmonary Gas Exchange
Gas Transport
Tissue Gas Exchange

84
Q

What is pulmonary ventilation (breathing)?

A

Air movement atmosphere and alveoli. It consists of two cyclic phases; Inspiration brings air into the lungs (inhalation), and expiration forces air out of the lungs (exhalation). It is regulated by autonomic nuclei in brainstem and skeletal muscles contract and relax changing thorax volume. Volume changes result in changes in pressure gradient between lungs and atmosphere and air moves down its pressure gradient.

85
Q

Quiet breathing (eupnea)

A

Rhythmic breathing at rest

86
Q

Forced breathing

A

vigorous breathing accompanying exercise

87
Q

Gas Transport: Carbon Dioxide

A

Carbon dioxide has three means of transportation; As CO2 dissolved in plasma (7%), As CO2 attached to amine group of globin portion of hemoglobin (23%), As bicarbonate dissolved in plasma (70%)

88
Q

Gas Transport: Oxygen

A

Blood’s ability to transport oxygen depends on; Solubility coefficient of oxygen, This is very low, and so very little oxygen dissolves in plasma. Presence of hemoglobin, The iron of hemoglobin attaches oxygen and about 98% of O2 in blood is bound to hemoglobin. HbO2 is oxyhemoglobin (with oxygen bound), HHb is deoxyhemoglobin (without bound oxygen).

89
Q

Quiet Breathing: Inspiration

A

The diaphragm and external intercostals contract for inspiration (diaphragm flattens and moves inferiorly, external intercostals elevate ribs). Increases volume of the chest cavity and pressure decreases in the chest cavity. Air moves down its pressure gradient into the lungs and energy is required for muscles to contract - therefore inspiration is an ACTIVE process.

90
Q

Quiet Breathing: Expiration

A

Diaphragm and external intercostals relax for expiration, diaphragm moves superiorly and the ribs are depressed. Decrease volume of the chest cavity and pressure increases in the chest cavity. Air moves down its pressure gradient out of the lungs and NO energy is required to relax the muscles - therefore expiration is a PASSIVE process (no muscles contract for quiet expiration).

91
Q

Forced Breathing: Forced Inspiration

A

The diaphragm and the external intercostals contract for inspiration. The sternocleidomastoid, scalenes, pectoralis minor, and the serratus posterior superior, contract for deep and labored inspiration. All of the muscles are located superiorly in the thorax and move the rib cage superiorly, laterally, and anteriorly increasing the volume.

92
Q

Explain the movement of muscles related to forced expiration.

A

The internal intercostals, abdominal muscles, transversus thoracis and the serratus posterior inferior contract during forced expiration. Contracting happens during hard expiration like coughing or blowing up a balloon. They can pull the ribcage inferiorly, medially, posteriorly, or compress the abdominal contents. Can be collectively be termed as accessory muscles of breathing when paired with the muscles of forced inspiration. Energy is required to contract these muscles, making forced expiration an active process.

93
Q

Explain Boyle’s Law and the relationship between volume and pressure

A

At a constant temperature, pressure (P) of a gas decreases if the volume (V) of the container increases, and vice versa. P1 and V1 represent the initial conditions and P2 and V2 represent the changed conditions. The equation is P1V1=P2V2. It has an inverse relationship between gas pressure and volume.

94
Q

Explain what an air pressure gradient is.

A

An air pressure gradient exists when force per unit area is greater in one place than another. If the two places are interconnected, the air flows from high to low pressure until the pressure is equal.

95
Q

How does breathing and boyle’s law relate?

A

Volume changes in the thoracic cavity as a result in pressure changes. As volume increases, the pressure will decreases and as volume decreases, pressure will increase.

96
Q

What are the 3 different volumes and pressures associated with breathing?

A

Atmospheric pressure
Intrapulmonary pressure
Intrapleural pressure

97
Q

Explain atmospheric pressure.

A

It is the pressure of the air in our an environment. It changes with the level of altitude, more increased altitude results in ‘thinner air’ and lower pressure. The sea level value is 760 mmHg = 14.7 lbs per square inch = 1 atm. In remained unchanged in the process of breathing.

98
Q

Explain intrapulmonary pressure.

A

It is the pressure in the alveoli and it fluctuates with your breathing. It can be higher, lower, or equal to atmospheric pressure. It is equal to atmospheric pressure at the end of inspiration and expiration.

99
Q

Explain intrapleural pressure.

A

It is the pressure in the pleural cavity, and it fluctuates with your breathing. It is lower than intrapulmonary pressure (keeps the lungs inflated by ‘pulling’ them outwards). It is about 4 mm Hg lower than intrapulmonary pressure between breaths and the lungs cling to the chest wall due to serous fluid surface tension.

100
Q

Explain the mechanics of Quiet inspiration.

A

The diaphragm and external intercostals contract increasing thoracic volume. The diaphragm movement accounts for 2/3 of volume change and external intercostals movement accounts for 1/3. Intrapleural volume increases, so intrapleural pressure decreases. The lungs are pulled by pleurae, so lung volume increases and intrapulmonary pressure decreases. Due to the fact that intrapulmonary pressure is less than atmospheric pressure, air flows in until the pressures are equal (typically 0.5 L flows in as tidal volume).

101
Q

Explain the mechanics of quiet expiration.

A

The diaphragm and external intercostals relax decreasing the thoracic volume. The volume in the pleural cavity decreases so the intrapleural pressure increases. The elastic recoil pulls the lungs inward, so the alveolar volume decreases and the intrapulmonary pressure increases. Since intrapulmonary pressure is greater than atmospheric pressure, air flows out until theses pressures are equal (about 0.5 L leaves the lungs).

102
Q

What is the condition atelectasis?

A

It is when you have a collapsed lung and it occurs if intrapleural and intrapulmonary pressures equalize due to air in the pleural cavity. It remains collapses until the air is removed from the pleural space.

103
Q

What is the lung condition Pneumothorax?

A

It is caused from air the pleural cavity. It can be introduced externally like a penetrating wound to the chest or internally through the rib lacerates the lung or if the alveolus ruptures. It may cause intrapleural and intrapulmonary pressures to equalize. A small pneumothorax resolves spontaneously and large pneumothorax is a medical emergency, a tube needs to be inserted into the pleural space to remove air.

104
Q

How does the autonomic nuclei within your brain control your breathing?

A

It is controlled through the respiratory center of your brainstem. There is a medullary respiratory center (in the medulla oblongata) that contains the ventral respiratory group (anterior medulla) and the dorsal respiratory group (posterior medulla). There is also the pontine respiratory center (in the pons) that smooths the transition between inspiration and expiration. The brainstems motor neurons influence respiratory muscles. The respiratory centre receives signals from receptors throughout the body to modify the breathing rate.

105
Q

How does the cerebral cortex play a role in your breathing?

A

The cerebral cortex can override the autonomic nuclei (i.e. you can consciously hold your breath or breath faster), but ultimately, the autonomic neurons will takes

106
Q

How does the hypothalamus and the limbic system influence your breathing?

A

The hypothalamus is based on body temperature (e.g. your breath faster when your warmer) and the limbic system (emotions) can influence your breathing rate and depth.

107
Q

What are chemoreceptors responsible for?

A

They monitor changes in the concentrations of H+, PCO2, and PO2. They are central chemoreceptors and peripheral chemoreceptors.

108
Q

What are central chemoreceptors responsible for?

A

They are located in the medulla and monitor pH of the cerebrospinal fluid (CSF). CSF pH changes are caused by changes in the blood carbon dioxide concentration. Carbon dioxide concentration is the most important (strongest) stimulus for breathing rate (high carbon dioxide rather than low oxygen).

109
Q

What are the peripheral chemoreceptors responsible for?

A

They are present in the aortic and carotid bodies and they are stimulated by changes in H+ or respiratory gases in the blood. Carotid chemoreceptors send signals to the respiratory center via the glossopharyngeal nerve and Aortic chemoreceptors send signals to the respiratory center via vagus nerve.

110
Q

What are irritant receptors responsible for?

A

They are located in air passageways and are stimulated by particulate matter. They cause exaggerated intake of breath followed by closure of the larynx, contraction of abdominal muscles and abrupt opening of vocal cords with an explosive blast of air.

111
Q

What are baroreceptors responsible for?

A

They are located in the pleurae and the bronchioles and they respond to stretch to prevent overinflation.

112
Q

What are proprioceptors responsible for?

A

They are in muscles and joints and are stimulated by body movements. They signal the respiratory center to increase breathing depth.

113
Q

What is eupnea?

A

The respiration rate for normal, quiet breathing is on average of 12 to 15 breaths per minute.

114
Q

What is apnea?

A

It is the absence of breathing and it can occur voluntarily (e.g. when swallowing or holding your breath). It may be drug-induced and can result from a neurological disease or trauma.

115
Q

What is sleep apnea?

A

It is the temporary cessation of breathing during sleep and may be treated with a CPAP (continuous positive airway pressure) machine

116
Q

Explain airflow related to pulmonary ventilation.

A

Airflow is the amount of air moving in and out of the lungs with each breath. It can depend on the pressure gradient established between atmospheric pressure and intrapulmonary pressure, or the resistance that occurs due to conditions within the airways, lungs, and chest wall. Flow is directly related to pressure gradient and inversely related to resistance. If pressure gradient increases, airflow to the lungs increases. If resistance increases, airflow lessens.

117
Q

What is the equation for airflow?

A

F=change in P/R
F = flow
Change in P = difference in pressure between atmosphere and intrapulmonary pressure = pressure gradient = Patm -Palv
R = resistance

118
Q

Explain what a pressure gradient is in regards to pulmonary ventilation??

A

It is the difference between atmospheric pressure and intrapulmonary pressure. It can be changed by altering volume of thoracic cavity.

119
Q

Explain resistance in regards to pulmonary ventilation.

A

The factors that increase difficulty moving air. It may be altered by change in elacticity of the chest wall and lungs as it decreases with aging, arthritis in the thoracic cage and replacement of elastic tissue with scar tissue (e.g. pulmonary fibrosis). It also may be altered by change in bronchiole diameter (size of air passageway). It can cause constriction from parasympathetic activity, histamine, or a cold and occlusion by excess mucus or inflammation. Lastly, it can be altered by the collapse of the alveoli that would increase the resistence. It can occur if alveolar type II cells are not producing surfactant (high surface tension of alveoli is not overcome). It is an important factor is premature infants called respiratory distress disorder (RDS)

120
Q

What does compliance have to do wit pulmonary ventilation?

A

Compliance is the opposite of resistance. Ease of with which the lungs and chest wall will expand. It is determined by surface tension and elasticity of chest and lung. The easier the lung expands, the greater the compliance.

121
Q

What is ventilation?

A

The process of moving air into and out of the lungs

122
Q

What is minute ventilation?

A

It is the amount of air moved between atmosphere and alveoli in 1 minute.
Tidal volume x Respiration rate = minute ventilation

123
Q

What is alveolar ventilation?

A

The amount of air reaching the alveoli per minute, deep breathing maximizes alveolar ventilation.
(Tidal volume - anatomic dead space) x respiration rate = alveolar ventilation

124
Q

What is alveolar gas exchange?

A

Between blood in pulmonary capillaries and alveoli

125
Q

What is systemic gas exchange?

A

Between blood in systemic capillaries and systemic cells

126
Q

Gas exchange

A

Both types of gas exchange depend on gradients. A gradient exists when partial pressure for a gas is higher in one region of the respiratory system than another. Gas moves from region of higher partial pressure to region of lower partial pressure until pressures become equal

127
Q

What is Dalton’s Law of Partial Pressures?

A

The total pressure in a mixture of gases is equal to the sum of the individual partial pressures.

128
Q

What is partial pressure?

A

It is the pressure exerted by each gas within a mixture of gases, measured in mmHg. It is written with P followed by the gas symbol (e.g. PO2). Each gas moves independently down its partial pressure gradient during gas exchange.

129
Q

What are the reasons partial pressures in the alveoli differ from atmospheric partial pressures?

A

The air from environment mixes with air remaining in anatomic dead space. Oxygen diffuses out of alveoli into the blood; carbon dioxide diffuses from blood to the alveoli. More water vapour is present in alveoli than in atomsphere.

130
Q

Within the alveoli……

A

The percentage and partial pressure of oxygen are lower than in the atmosphere and carbon dioxide is higher than in the atmosphere. The partial pressures of respiratory gases normally stay constant.

131
Q

In systemic cells, how do partial pressures of gases reflect cellular respiration?

A

With the use of oxygen and carbon dioxide the percentage of oxygen is lower while carbon dioxide is higher in the alveoli. Under resting conditions, the partial pressures remain constant.

132
Q

In circulating blood, why are the gas partial pressures not constant?

A

Oxygen enters the blood in pulmonary capillaries and carbon dioxide leaves. While oxygen eaves blood in systemic capillaries and carbon dioxide enters.

133
Q

Define Henry’s Law of Gas Solubility.

A

At a given temperature, the solubility of a gas in liquid is dependent upon the partial pressure of the gas in the air and the solubility coefficient.

134
Q

How does the partial pressure of the gas in the air affect henry’s law?

A

It is the driving force moving a gas into a liquid. It is determined by total pressure and percentage of gas in the mixture. For example, carbon dioxide is forced into soft drinks under high pressure.

135
Q

How does the solubility coefficient affect henry’s law?

A

It is the volume of gas that dissolves in a specified volume of a liquid at a give temperature and pressure. A constant that depends upon interactions between molecules of the gas and liquid.

136
Q

Explain how gases vary in their solubility in water.

A

Carbon dioxide is about 24 times as soluble as oxygen. Nitrogen is about half as soluble as oxygen since it does not normally dissolve in blood in significant amounts. Gases with low solubility require larger pressure of the liquid.

137
Q

What is decompression sickness?

A

This occurs when a diver is submerged in water beyond a certain depth and returns too quickly to the surface. Nitrogen is forced into the blood due to to the higher pressure. The dissolved nitrogen bubbles out of solution while still in the blood and tissues.

138
Q

Explain how decompression sickness can be treated with hyperbaric oxygen chambers.

A

The partial pressure gradient for oxygen increases and additional oxygen can dissolve in blood plasma. It can be used for other disorders such as carbon monoxide poisoning.

139
Q

How do anatomical features of the membrane contribute to efficiency of gas exchange?

A

Larger surface area, minimal thickness, and the fusion of blood vessels and alveolar basement membranes

140
Q

Explain ventilation-perfusion coupling affects efficiency of gas exchange at the respiratory membrane.

A

Based on the ability of the bronchioles to regulate airflow and arterioles to regulate blood flow (based on smooth muscle constriction or relaxation). Ventilation changes by bronchodilation or bronchoconstriction (e.g. dilation is response to increased PCO2 in air in the bronchiole). Perfusion changes by pulmonary arteriole dilation or constriction (e.g. dilation is response to either decreased or increased PCO2 in the blood).

141
Q

Airway obstruction

A

decreased airflow into alveoli e.g. asthma, bronchitis

142
Q

Thickened respiratory membrane

A

decreased pulmonary gas exchange e.g. pulmonary edema, pneumonia

143
Q

Loss of respiratory membrane surface

A

decreased pulmonary gas exchange e.g. emphysema, lung cancer

144
Q

Arthritis or deformities of thoracic cage or vertebral column

A

Impaired ability to cause dimensional volume changes in thoracic cavity e.g. rheumatoid arthritis, congenital deformities

145
Q

Paralysis of respiratory muscles

A

impaired ability to cause dimensional volume changes in thoracic cavity e.g. polio, muscular dystrophy, myasthenia gravis

146
Q

Brainstem injury or oversedation of respiratory center

A

decreased ability to stimulate muscles of breathing e.g. trauma, drug use

147
Q

Spinal cord injuries

A

decreased ability to stimulate muscles of breathing e.g. trauma (driving or motorcycle accident)

148
Q

Pulmonary embolism

A

Blockage in pulmonary artery, and blood does not reach lung capillaries for gas exchange e.g. slowed blood flow from immobilization (prolonged bed rest, long plane flight, confinement to wheelchair)

149
Q

Anemia

A

Decreased erythrocytes or hemoglobin concentration with decreased gas transprt e.g. low iron, pernicious (inability to absorb B12)

150
Q

Decreased blood flow

A

decrease gas transport and gas exchange e.g. atherosclerosis, congestive heart failure, hemorrhage

BIOL1046 Human Biology II (14 decks)

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