Respiratory System

Question 1

Introduction

The two systems that cooperate to supply O2 and eliminate CO2 are the cardio………… and the re…………………. system.
The respiratory system provides for gas exchange.
The cardiovascular system transports the respiratory gases.
Failure of either system has the same effect on the body: disruption of ho………… and rapid d…….. of c……… from ox……….. starvation and bui……. of waste products.
Respiration is the exchange of gases between the atmosphere, blood, and cells. It takes place in three basic steps: ven………. (breathing), exte……….(pulmonary) respi……….., and int……(tissue) respiration.

Answer 1

The two systems that cooperate to supply O2 and eliminate CO2 are the cardiovascular and the respiratory system.
The respiratory system provides for gas exchange.
The cardiovascular system transports the respiratory gases.
Failure of either system has the same effect on the body: disruption of homeostasis and rapid death of cells from oxygen starvation and buildup of waste products.
Respiration is the exchange of gases between the atmosphere, blood, and cells. It takes place in three basic steps: ventilation (breathing), external (pulmonary) respiration, and internal (tissue) respiration.

Question 2

Respiratory System Anatomy

Nose
Pharynx = th........
Larynx = vo.............
Trachea = win.............
Bronchi = ai.................
Lungs

Locations of infections
- upper respiratory tract is above ………… cords
- lower respiratory ………. is ……… vocal cords
The conducting system consists of a series of cavities and tubes - nose, pharynx, larynx, trachea, bronchi, bronchiole, and terminal bronchioles - that conduct air into the lungs. The respiratory portion consists of the area where gas ………… occurs - respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Answer 2

Respiratory System Anatomy

Nose
Pharynx = throat
Larynx = voicebox
Trachea = windpipe
Bronchi = airways
Lungs

Locations of infections
upper respiratory tract is above vocal cords
lower respiratory tract is below vocal cords
The conducting system consists of a series of cavities and tubes - nose, pharynx, larynx, trachea, bronchi, bronchiole, and terminal bronchioles - that conduct air into the lungs. The respiratory portion consists of the area where gas exchange occurs - respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Question 3

Trachea

The trachea (windpipe) extends from the la……. to the primary b…………
It is composed of ………… muscle and C-shaped rings of c………. and is lined with pseu…………. ciliated columnar epithelium.
The cartilage rings keep the airway o………….
The ci……. of the epithelium s……… de…….. away from the lungs and back to the throat to be swallowed.

Answer 3

Trachea

The trachea (windpipe) extends from the larynx to the primary bronchi.
It is composed of smooth muscle and C-shaped rings of cartilage and is lined with pseudostratified ciliated columnar epithelium.
The cartilage rings keep the airway open.
The cilia of the epithelium sweep debris away from the lungs and back to the throat to be swallowed.

Question 4

Histology of the Trachea

Ciliated pseud…………. columnar epith…………
Hyaline cart………. as C-shaped structure closed by trach………. muscle

Answer 4

Histology of the Trachea

Ciliated pseudostratified columnar epithelium
Hyaline cartilage as C-shaped structure closed by trachealis muscle

Question 5

Airway Epithelium

Ciliated pseud……….. columnar epithelium with g…………. cells produce a moving mass of m………….

Answer 5

Airway Epithelium

Ciliated pseudostratified columnar epithelium with goblet cells produce a moving mass of mucus.

Question 6

Tracheostomy and Intubation

Re-establishing airflow past an airway obs……….
crushing inju…….. to lar……….. or chest
swelling that closes airway
vomit or foreign object

Trach……… is incision in trachea below cricoid cartilage if larynx is obstructed

Intubation is passing a tube from mouth or nose through la……… and tra…………..

Answer 6

Tracheostomy and Intubation

Re-establishing airflow past an airway obstruction
crushing injury to larynx or chest
swelling that closes airway
vomit or foreign object
Tracheostomy is incision in trachea below cricoid cartilage if larynx is obstructed
Intubation is passing a tube from mouth or nose through larynx and trachea

Question 7

Bronchi

The trachea divides into the right and left p………….. b…………
The bronchial tree consists of the trachea, prim…….. bronchi, secon………… bronchi, tert……. bronchi, bronchioles, and terminal bronchioles.
Walls of bronchi contain rings of ca………..
Walls of bronchioles contain ……….. muscle.

Answer 7

Bronchi

The trachea divides into the right and left pulmonary bronchi.
The bronchial tree consists of the trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, and terminal bronchioles.
Walls of bronchi contain rings of cartilage.
Walls of bronchioles contain smooth muscle.

Question 8

Bronchi and Bronchioles

Primary bronchi supply each l………

Secondary bronchi supply each l………… of the lu……….. (3 right + 2 left)

Tertiary bronchi supply each broncho…………. segment

Repeated branchings called bron……….. form a bronchial tree

Answer 8

Bronchi and Bronchioles

Primary bronchi supply each lung
Secondary bronchi supply each lobe of the lungs (3 right + 2 left)
Tertiary bronchi supply each bronchopulmonary segment
Repeated branchings called bronchioles form a bronchial tree

Question 9

Histology of Bronchial Tree

Epithelium changes from pseud………… ciliated columnar to nonci…….. simple cuboidal as pass deeper into lungs
Incomplete rings of cartilage repl……… by rings of sm……… muscle & then conn……… tissue
- sympathetic NS & adrenal gland release epin………. that re……… smo…….. muscle & dila…….. airways
- asthma attack or allergic reactions constrict distal bronchiole smooth muscle
- nebulization therapy = inhale mist with chemicals that relax muscle & reduce thickness of mu……….

Answer 9

Histology of Bronchial Tree

Epithelium changes from pseudostratified ciliated columnar to nonciliated simple cuboidal as pass deeper into lungs
Incomplete rings of cartilage replaced by rings of smooth muscle & then connective tissue
sympathetic NS & adrenal gland release epinephrine that relaxes smooth muscle & dilates airways
asthma attack or allergic reactions constrict distal bronchiole smooth muscle
nebulization therapy = inhale mist with chemicals that relax muscle & reduce thickness of mucus

Question 10

Pleural Membranes & Pleural Cavity

Vis……… pleura covers lungs and the pa………. pleura lines the ribcage & covers upper surface of diaphragm
Pleural cavity is pot…….. space between ri… & lungs

Answer 10

Pleural Membranes & Pleural Cavity

Visceral pleura covers lungs and the parietal pleura lines the ribcage & covers upper surface of diaphragm
Pleural cavity is potential space between ribs & lungs

Question 11

Lungs - Overview

Lungs are paired organs in the thoracic cavity; they are enclosed and protected by the ple…….. membrane.

The pari……. pleura is the outer layer which is attached to the wall of the thoracic cavity.

The visc….. pleura is the inner layer, covering the lungs themselves.

Between the pleurae is a small p………. ………, the pleural cavity, which contains a lu……… fluid secreted by the membranes.

The pleural cavities may fill with a….. (pneumothorax) or b………. (haemothorax).

A pneumor………… may cause a partial or complete collapse of the lung.

The lungs extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly

Answer 11

Lungs - OverviewLungs are paired organs in the thoracic cavity; they are enclosed and protected by the pleural membrane.

The parietal pleura is the outer layer which is attached to the wall of the thoracic cavity.
The visceral pleura is the inner layer, covering the lungs themselves.

Between the pleurae is a small potential space, the pleural cavity, which contains a lubricating fluid secreted by the membranes.

The pleural cavities may fill with air (pneumothorax) or blood (haemothorax).
A pneumorthorax may cause a partial or complete collapse of the lung.

The lungs extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly

Question 12

Lungs - Overview

The lungs almost totally fill the th………..
The right lung has thr……. lobes separated by two fissu……..; the left lung has two lobes separated by o….. fissure and a depression, the cardiac n……….
The secondary bronchi give rise to branches called tertiary (segmental) bronchi, which supply segments of lung tissue called bronc…. segments.
Each bronchopulmonary segment consists of many small compartments called lob…….., which contain lymphatics, arterioles, venules, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Answer 12

Lungs - Overview

The lungs almost totally fill the thorax.
The right lung has three lobes separated by two fissures; the left lung has two lobes separated by one fissure and a depression, the cardiac notch.
The secondary bronchi give rise to branches called tertiary (segmental) bronchi, which supply segments of lung tissue called bronchopulmonary segments.
Each bronchopulmonary segment consists of many small compartments called lobules, which contain lymphatics, arterioles, venules, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Question 13

Gross Anatomy of Lungs

Base, apex (cupula), costal surface, cardiac notch
Oblique & horizontal fissure in right lung results in …. lobes
Oblique fissure only in left lung produces ….. lobes

Answer 13

Gross Anatomy of Lungs

Base, apex (cupula), costal surface, cardiac notch
Oblique & horizontal fissure in right lung results in 3 lobes
Oblique fissure only in left lung produces 2 lobes

Question 14

Mediastinal Surface of Lungs

Blood vessels & airways enter lungs at hi……
Forms ro……. of lungs
Covered with p……….. (parietal becomes visceral)

Answer 14

Mediastinal Surface of Lungs

Blood vessels & airways enter lungs at hilus
Forms root of lungs
Covered with pleura (parietal becomes visceral)

Question 15

Structures within a Lobule of Lung

Branchings of single arteriole, venule & bronchiole are wrapped by elastic C….
Respiratory bron……..
-simple squ………
Alveolar ducts surrounded by alveolar sacs & alveoli
- s……. is 2 or more alveoli sharing a common opening

Answer 15

Structures within a Lobule of Lung

Branchings of single arteriole, venule & bronchiole are wrapped by elastic CT
Respiratory bronchiole
simple squamous
Alveolar ducts surrounded by alveolar sacs & alveoli
sac is 2 or more alveoli sharing a common opening

Question 16

Alveoli

Alveolar walls consist of type …. alveolar (squ……… pulmonary epithelial) cells, type .. alveolar (septal) cells, and alveolar mac………. (dust cells).
Type II alveolar cells secrete al…….. fluid, which keeps the alveolar cells moist and which contains a component called surfactant. Surfactant lo……… the surface tension of alveolar fluid, preventing the collapse of alveoli with each expiration.
Respiratory Distress Syndrome is a disorder of premature infants in which the alveoli do not have sufficient surfactant to remain open.
Gas exchange occurs across the alveolar-capillary membrane.

Answer 16

Alveoli

Alveolar walls consist of type I alveolar (squamous pulmonary epithelial) cells, type II alveolar (septal) cells, and alveolar macrophages (dust cells).
Type II alveolar cells secrete alveolar fluid, which keeps the alveolar cells moist and which contains a component called surfactant. Surfactant lowers the surface tension of alveolar fluid, preventing the collapse of alveoli with each expiration.
Respiratory Distress Syndrome is a disorder of premature infants in which the alveoli do not have sufficient surfactant to remain open.
Gas exchange occurs across the alveolar-capillary membrane.

Question 17

Double Blood Supply to the Lungs

Deoxygenated blood arrives through pul……. trunk from the right ven……..
Bronchial arteries branch off of the aorta to supply oxygenated blood to lung …………..
Venous drainage returns all blood to heart
Le……….. p…………. in venous system
Pulmonary blood vessels constrict in response to low …….. levels so as not to pick up C……… on their way through the lungs

Answer 17

Deoxygenated blood arrives through pulmonary trunk from the right ventricle
Bronchial arteries branch off of the aorta to supply oxygenated blood to lung tissue
Venous drainage returns all blood to heart
Less pressure in venous system
Pulmonary blood vessels constrict in response to low O2 levels so as not to pick up CO2 on their way through the lungs

Question 18

Clinical Applications

Nebulization, a procedure for administering medication as small dr……….. suspended in air into the res…………. tract, is used to treat many different types of respiratory d…………..

In the lungs vaso………….. in response to hypoxia diverts pulmonary blood from poorly ventilated areas to ………. ventilated areas. This phenomenon is known as ven…….. – p…………….. cou………..

Answer 18

Clinical Applications

Nebulization, a procedure for administering medication as small droplets suspended in air into the respiratory tract, is used to treat many different types of respiratory disorders.

In the lungs vasoconstriction in response to hypoxia diverts pulmonary blood from poorly ventilated areas to well ventilated areas. This phenomenon is known as ventilation – perfusion coupling.

Question 19

PULMONARY VENTILATION

Respiration occurs in three basic steps: pulmonary ven………, external res……….., and internal res………….
Inspiration (inhalation) is the process of bringing air into the lungs.
The movement of air into and out of the lungs depends on pressure changes governed in part by Boyle’s law, which states that the volume of a gas varies inv……… with press………, assuming that tem…………… is constant.

Answer 19

PULMONARY VENTILATION

Respiration occurs in three basic steps: pulmonary ventilation, external respiration, and internal respiration.
Inspiration (inhalation) is the process of bringing air into the lungs.
The movement of air into and out of the lungs depends on pressure changes governed in part by Boyle’s law, which states that the volume of a gas varies inversely with pressure, assuming that temperature is constant.

Question 20

Breathing or Pulmonary Ventilation

Air moves into lungs when pressure inside lungs is l……… than at………………pressure
How is this accomplished?
Air moves out of the lungs when pressure inside lungs is gr……… than atmo……… pressure
How is this accomplished?
Atmospheric pressure = ….. atm or ……mm Hg

Answer 20

Breathing or Pulmonary Ventilation

Air moves into lungs when pressure inside lungs is less than atmospheric pressure
How is this accomplished?
Air moves out of the lungs when pressure inside lungs is greater than atmospheric pressure
How is this accomplished?
Atmospheric pressure = 1 atm or 760mm Hg

Question 21

Boyle’s Law

As the size of closed container de………., pressure inside is incr……….
The molecules have less wall a….. to strike so the pressure on each inch of area incr………..

Answer 21

Boyle’s Law

As the size of closed container decreases, pressure inside is increased
The molecules have less wall area to strike so the pressure on each inch of area increases.

Question 22

Dimensions of the Chest Cavity

Breathing in re……….. muscular activity & chest size changes
Contraction of the diaphragm flattens the dome and incre……… the vert…….. di……… of the c……….

Answer 22

Dimensions of the Chest Cavity

Breathing in requires muscular activity & chest size changes
Contraction of the diaphragm flattens the dome and increases the vertical dimension of the chest

Question 23

Inspiration

The first step in expanding the lungs involves contraction of the main insp………… muscle, the diaphragm.
Inhalation occurs when alveolar (intrapu………..) pressure falls bel…… atmospheric pressure. Contraction of the diaphragm and ext……… intercostal muscles increases the size of the th…….., thus decreasing the intra………
(intrathoracic) pressure so that the lungs expand. Expa……. of the lungs decr……. alveolar pres……. .so that air moves along the pressure grad……… . from the atmosphere into the lungs.
During forced inhalation, accessory muscles of inspiration (sternocleidomastoids, scalenes, and pectoralis minor) are also used.

Answer 23

Inspiration

The first step in expanding the lungs involves contraction of the main inspiratory muscle, the diaphragm.
Inhalation occurs when alveolar (intrapulmonic) pressure falls below atmospheric pressure. Contraction of the diaphragm and external intercostal muscles increases the size of the thorax, thus decreasing the intrapleural (intrathoracic) pressure so that the lungs expand. Expansion of the lungs decreases alveolar pressure so that air moves along the pressure gradient from the atmosphere into the lungs.
During forced inhalation, accessory muscles of inspiration (sternocleidomastoids, scalenes, and pectoralis minor) are also used.

Question 24

Quiet Inspiration

Diaphragm moves ….. cm & ribs lifted by muscles
Intrath………. pressure falls and 2-3 liters inhaled

Answer 24

Quiet Inspiration

Diaphragm moves 1 cm & ribs lifted by muscles
Intrathoracic pressure falls and 2-3 liters inhaled

Question 25

Expiration

Expiration (exhalation) is the movement of air out of the lungs.

Exhalation occurs when alveolar pressure is h……… than atm………… pressure. Relaxation of the diaphragm and external intercostal muscles results in elastic re……..of the chest wall and lungs, which increases intr……… pressure, decreases lung volume, and increases al……… pressure so that air moves from the lungs to the atmosphere. There is also an inward pull of surface tension due to the film of alveolar fluid.

Exhalation becomes active during labored breathing and when air movement out of the lungs is impeded. Forced expiration employs contraction of the internal intercostals and abdominal muscles.

Answer 25

Expiration

Expiration (exhalation) is the movement of air out of the lungs.
Exhalation occurs when alveolar pressure is higher than atmospheric pressure. Relaxation of the diaphragm and external intercostal muscles results in elastic recoil of the chest wall and lungs, which increases intrapleural pressure, decreases lung volume, and increases alveolar pressure so that air moves from the lungs to the atmosphere. There is also an inward pull of surface tension due to the film of alveolar fluid.
Exhalation becomes active during labored breathing and when air movement out of the lungs is impeded. Forced expiration employs contraction of the internal intercostals and abdominal muscles.

Question 26

Quiet Expiration

Passive process with ………. muscle action
Elastic recoil & surface tension in alveoli pulls in……….
Alveolar pressure increases………… and air is pushed out
.

Answer 26

Quiet Expiration

Passive process with no muscle action
Elastic recoil & surface tension in alveoli pulls inward
Alveolar pressure increases & air is pushed out

Question 27

Labored Breathing

Forced expiration
abdominal muscle movements f………. diap…………… up
internal intercostals dep……… ribs
Forced inspiration
sternocleidomastoid, scalenes & pectoralis minor lift chest upwards as you gasp for air

Answer 27

Labored Breathing

Forced expiration
abdominal muscle movements force diaphragm up
internal intercostals depress ribs
Forced inspiration
sternocleidomastoid, scalenes & pectoralis minor lift chest upwards as you gasp for air

Question 28

Alveolar pressure d………… & air rushes i…………..

Alveolar pressure inc………… & air rushes o…………

Answer 28

Alveolar pressure decreases & air rushes in

Alveolar pressure increases & air rushes out

Question 29

Compliance of the Lungs

Ease with which lungs & chest wall expand depends upon ela………. of lungs & surface ten………….
Some diseases reduce compliance
tuberculosis forms scar tissue
pulmonary oedema — fluid in lungs & reduced surfactant
paralysis

Answer 29

Compliance of the Lungs

Ease with which lungs & chest wall expand depends upon elasticity of lungs & surface tension
Some diseases reduce compliance
tuberculosis forms scar tissue
pulmonary oedema — fluid in lungs & reduced surfactant
paralysis

Question 30

Airway Resistance

Resistance to airflow depends upon airway size
inc……….. size of chest
airways inc……… in diameter
contract s……….. muscles in air………….
decreases in diameter

Answer 30

Airway Resistance

Resistance to airflow depends upon airway size
increase size of chest
airways increase in diameter
contract smooth muscles in airways
decreases in diameter

Question 31

Breathing Patterns

Eupnea is normal variation in breathing rate and depth.
Apnea refers to breath holding e.g. sleep apnea
Dys……….. relates to pa………. or difficult breathing.
Tac………… involves rapid breathing rate.

Costal breathing requires combinations of various patterns of intercostal and extracostal muscles, usually during need for increased vent………., as with exercise.
Diaphragmatic breathing is the usual mode of operation to move air by contracting and relaxing the diaphragm to change the lung volume.
Modified respiratory movements are used to express emot………. and to c……….. air passageways.

Answer 31

Breathing Patterns

Eupnea is normal variation in breathing rate and depth.
Apnea refers to breath holding e.g. sleep apnea
Dyspnea relates to painful or difficult breathing.
Tachypnea involves rapid breathing rate.
Costal breathing requires combinations of various patterns of intercostal and extracostal muscles, usually during need for increased ventilation, as with exercise.
Diaphragmatic breathing is the usual mode of operation to move air by contracting and relaxing the diaphragm to change the lung volume.
Modified respiratory movements are used to express emotions and to clear air passageways.

Question 32

LUNG VOLUMES AND CAPACITIES

Air volumes exchanged during breathing and rate of ven…………. are measured with a spiro………….., or respirometer, and the record is called a spirogram.
Among the pulm………. air volumes exchanged in ventilation are tidal (500 mL), inspiratory reserve (3100 mL), expiratory reserve (1200 mL), residual (1200 mL) and minimal volumes. Only about 35… ml of the tidal vol…… actually reaches the alveoli, the other 150 mL remains in the airways as anatomic dead space.
Pulmonary lung capacities, the sum of two or more volumes, include inspiratory (3600 mL), functional residual (2400 mL), vital (4800 mL), and total lung (6000 mL) capacities.
The minute volume of respiration is the total volume of air taken in during one minute (tidal volume x 12 respirations per minute = 6000 mL/min).

Answer 32

LUNG VOLUMES AND CAPACITIES

Air volumes exchanged during breathing and rate of ventilation are measured with a spiromometer, or respirometer, and the record is called a spirogram.
Among the pulmonary air volumes exchanged in ventilation are tidal (500 mL), inspiratory reserve (3100 mL), expiratory reserve (1200 mL), residual (1200 mL) and minimal volumes. Only about 350 ml of the tidal volume actually reaches the alveoli, the other 150 mL remains in the airways as anatomic dead space.
Pulmonary lung capacities, the sum of two or more volumes, include inspiratory (3600 mL), functional residual (2400 mL), vital (4800 mL), and total lung (6000 mL) capacities.
The minute volume of respiration is the total volume of air taken in during one minute (tidal volume x 12 respirations per minute = 6000 mL/min).

Question 33

Lung Volumes and Capacities

Tidal volume = amount air moved during ………… breathing
MVR= minute ventilation is amount of …………. moved in a ……………….
Reserve volumes —- amount you can breathe either in or out above that amount of tidal volume
Residual volume = 1200 mL permanently trapped air in system
Vital capa…………. & total lu………. capacity are sums of the other volumes

Answer 33

Lung Volumes and Capacities

Tidal volume = amount air moved during quiet breathing
MVR= minute ventilation is amount of air moved in a minute
Reserve volumes —- amount you can breathe either in or out above that amount of tidal volume
Residual volume = 1200 mL permanently trapped air in system
Vital capacity & total lung capacity are sums of the other volumes

Question 34

What is Composition of Air?

Air = 21% ….., 79% ….. and .04% …..
Alveolar air = 14% …., 79% N…… and 5.2% CO2
Expired air = 16% ….., 79% N2 and 4.5% CO2
Observations
alveolar air has less …… since absorbed by blood
Anatomical dead space = 150 mL of 500 mL of tidal volume

Answer 34

Air = 21% O2, 79% N2 and .04% CO2
Alveolar air = 14% O2, 79% N2 and 5.2% CO2
Expired air = 16% O2, 79% N2 and 4.5% CO2
Observations
alveolar air has less O2 since absorbed by blood
Anatomical dead space = 150 mL of 500 mL of tidal volume

Question 35

Henry’s Law

Quantity of a gas that will dissolve in a liquid depends upon the amount of gas pr……….. and its sol………….. coefficient
explains why you can breathe compressed air while scuba diving despite 79% Nitrogen
N2 has very low solubility unlike CO2 (soda cans)
dive deep & increased pressure forces more N2 to dissolve in the blood (nitrogen narcosis)
decompression sickness if come back to surface too fast or stay deep too long
Breathing O2 under pressure dissolves ………. O2 in blood

Answer 35

Henry’s Law

Quantity of a gas that will dissolve in a liquid depends upon the amount of gas present and its solubility coefficient
explains why you can breathe compressed air while scuba diving despite 79% Nitrogen
N2 has very low solubility unlike CO2 (soda cans)
dive deep & increased pressure forces more N2 to dissolve in the blood (nitrogen narcosis)
decompression sickness if come back to surface too fast or stay deep too long
Breathing O2 under pressure dissolves more O2 in blood

Question 36

Hyperbaric Oxygenation

A major clinical application of Henry’s law is hyperbaric oxygenation.
Use of pressure to dissolve more O2 in the blood
treatment for patients with anaerobic bacterial infections (tetanus and gangrene)
an………… bacteria die in the presence of O2
Hyperbaric chamber pressure raised to 3 to 4 atmospheres so that tissues absorb ……… ……..
Used to treat heart disorders, carbon monoxide poisoning, cerebral edema, bone infections, gas embolisms & crush injuries

Answer 36

Hyperbaric Oxygenation

A major clinical application of Henry’s law is hyperbaric oxygenation.
Use of pressure to dissolve more O2 in the blood
treatment for patients with anaerobic bacterial infections (tetanus and gangrene)
anaerobic bacteria die in the presence of O2
Hyperbaric chamber pressure raised to 3 to 4 atmospheres so that tissues absorb more O2
Used to treat heart disorders, carbon monoxide poisoning, cerebral edema, bone infections, gas embolisms & crush injuries

Question 37

External Respiration

O2 and CO2 diffuse from areas of their hi………. partial pressures to areas of their low……….. partial pressures
Diffusion depends on p…………… pressure diff……….
Compare gas movements in pulmonary capillaries to tissue capillaries

Answer 37

External Respiration

O2 and CO2 diffuse from areas of their higher partial pressures to areas of their lower partial pressures
Diffusion depends on partial pressure differences
Compare gas movements in pulmonary capillaries to tissue capillaries

Question 38

Rate of Diffusion of Gases

Depends upon partial pressure of gases in air
- p O2 at sea level is 160 mm Hg
- 10,000 feet is 110 mm Hg / 50,000 feet is 18 mm Hg
Large surface area of our alveoli
Diffusion distance (membrane thickness) is very small
Solubility & molecular weight of gases
- O2 smaller molecule diffuses somewhat faster
- CO2 dissolves 24X more easily in wa……… so net outward diffusion of CO2 is much faster
- disease produces hypoxia before hypercapnia
lack of O2 before too much CO2

Answer 38

Rate of Diffusion of Gases

Depends upon partial pressure of gases in air
p O2 at sea level is 160 mm Hg
10,000 feet is 110 mm Hg / 50,000 feet is 18 mm Hg
Large surface area of our alveoli
Diffusion distance (membrane thickness) is very small
Solubility & molecular weight of gases
O2 smaller molecule diffuses somewhat faster
CO2 dissolves 24X more easily in water so net outward diffusion of CO2 is much faster
disease produces hypoxia before hypercapnia
lack of O2 before too much CO2

Question 39

Haemoglobin and Oxygen Partial Pressure

The most important factor that determines how much oxygen combines with haemoglobin is PO2.
The relationship between the percent saturation of haemoglobin and PO2 is illustrated the oxygen-hemoglobin dissociation curve.
The greater the PO2, the m……… oxygen will combine with hae…………., until the available haemoglobin molecules are sa……………

Answer 39

Haemoglobin and Oxygen Partial Pressure

The most important factor that determines how much oxygen combines with haemoglobin is PO2.
The relationship between the percent saturation of haemoglobin and PO2 is illustrated the oxygen-hemoglobin dissociation curve.
The greater the PO2, the more oxygen will combine with haemoglobin, until the available haemoglobin molecules are saturated.

Question 40

Hemoglobin and Oxygen Partial Pressure

Blood is almost fully saturated at pO2 of ……mmHg
people OK at high altitudes & with some disease
Between 40 & 20 mm Hg, large amounts of O2 are released as in areas of need like contr………. muscle

Answer 40

Hemoglobin and Oxygen Partial Pressure

Blood is almost fully saturated at pO2 of 60mmHg
people OK at high altitudes & with some disease
Between 40 & 20 mm Hg, large amounts of O2 are released as in areas of need like contracting muscle

Question 41

Oxygen Transport in the Blood

Oxyhemoglobin contains 98.5% chemically combined oxygen and haemoglobin
inside red blood cells
Does not dissolve easily in water
only 1.5% transported dissolved in bl……….
Only the dissolved O2 can diff………… into tissues
Factors affecting dissociation of O2 from haemoglobin are important
Oxygen dissociation curve shows levels of saturation and oxygen partial pressures

Answer 41

Oxygen Transport in the Blood

Oxyhemoglobin contains 98.5% chemically combined oxygen and haemoglobin
inside red blood cells
Does not dissolve easily in water
only 1.5% transported dissolved in blood
Only the dissolved O2 can diffuse into tissues
Factors affecting dissociation of O2 from haemoglobin are important
Oxygen dissociation curve shows levels of saturation and oxygen partial pressures

Question 42

Other Factors Affecting Haemoglobin Affinity for Oxygen

In an acid (low ………..) environment, O2 splits more rea……….. from haemoglobin. This is referred to as the Bohr effect.
Low blood pH (acidic conditions) results from high PCO2.
Within limits, as temperature increases, so does the amount of oxygen released from hemoglobin. Active cells require more oxygen, and active cells (such as contracting muscle cells) liberate more acid and heat. The acid and heat, in turn, stimulate the oxyhae……….. to release its oxygen.
BPG (2, 3-biphosphoglycerate) is a substance formed in red blood cells during gly…………. The greater the level of BPG, the more oxygen is released from haem………….

Answer 42

Other Factors Affecting Haemoglobin Affinity for Oxygen

In an acid (low pH) environment, O2 splits more readily from haemoglobin. This is referred to as the Bohr effect.
Low blood pH (acidic conditions) results from high PCO2.
Within limits, as temperature increases, so does the amount of oxygen released from hemoglobin. Active cells require more oxygen, and active cells (such as contracting muscle cells) liberate more acid and heat. The acid and heat, in turn, stimulate the oxyhaemoglobin to release its oxygen.
BPG (2, 3-biphosphoglycerate) is a substance formed in red blood cells during glycolysis. The greater the level of BPG, the more oxygen is released from haemoglobin

Question 43

Acidity & Oxygen Affinity for Hb

As acidity incr………., O2 affinity for Hb ……………..
Bohr effect
H+ binds to haemoglobin & a……… it
O2 left behind in needy tissues

Answer 43

Acidity & Oxygen Affinity for Hb

As acidity increases, O2 affinity for Hb decreases
Bohr effect
H+ binds to haemoglobin & alters it
O2 left behind in needy tissues

Question 44

pCO2 & Oxygen Release

As pCO2 rises with exercise, O2 is released more easily
CO2 converts to ca……….. acid & becomes H+ and b…………… ions & lowers p……….

Answer 44

pCO2 & Oxygen Release

As pCO2 rises with exercise, O2 is released more easily
CO2 converts to carbonic acid & becomes H+ and bicarbonate ions & lowers pH.

Question 45

Temperature & Oxygen Release

As temperature inc…………, more ……. is released
Metabolic activity & heat
More BPG, more O2 released
RBC activity
hormones like thyroxine & gr……… hormone

Answer 45

Temperature & Oxygen Release

As temperature increases, more O2 is released
Metabolic activity & heat
More BPG, more O2 released
RBC activity
hormones like thyroxine & growth hormone

Question 46

Oxygen Affinity & Fetal Haemoglobin

Differs from adult in structure & aff……… for O2
When pO2 is low, can carry more ……
Maternal blood in pla………… has less ………

Answer 46

Oxygen Affinity & Fetal Haemoglobin

Differs from adult in structure & affinity for O2
When pO2 is low, can carry more O2
Maternal blood in placenta has less O2

Question 47

Foetal Haemoglobin

Foetal haemoglobin has a higher af………. for oxy…….. because it binds BPG less strongly and can carry m……… oxy……….. to offset the low oxygen saturation in maternal blood in the plac………..
Because of the strong att………… of carbon mon…….. (CO) to haem………, even small concen………. of CO will re…… the oxygen carrying capacity leading to hypoxia and carbon monoxide poisoning (Clinical Application).

Answer 47

Foetal Haemoglobin

Foetal haemoglobin has a higher affinity for oxygen because it binds BPG less strongly and can carry more oxygen to offset the low oxygen saturation in maternal blood in the placenta.
Because of the strong attraction of carbon monoxide (CO) to haemoglobin, even small concentrations of CO will reduce the oxygen carrying capacity leading to hypoxia and carbon monoxide poisoning (Clinical Application).

Question 48

Carbon Monoxide Poisoning

CO from car exhaust & tobacco smoke
Binds to H….. haeme group more suc………… than O2
CO pois………..
Treat by administering pure O……

Answer 48

Carbon Monoxide Poisoning

CO from car exhaust & tobacco smoke
Binds to Hb haeme group more successfully than O2
CO poisoning
Treat by administering pure O2

Question 49

Control of Ventilation: The Respiratory Center

The area of the brain from which nerve impulses are sent to respiratory muscles is located bilat….. in the reticular formation of the brain ………. This respiratory center consists of a med……….. rhyth…….. area (inspiratory and expiratory areas), pneumotaxic area, and apneustic area.

Answer 49

Control of Ventilation: The Respiratory Center

The area of the brain from which nerve impulses are sent to respiratory muscles is located bilaterally in the reticular formation of the brain stem. This respiratory center consists of a medullary rhythmicity area (inspiratory and expiratory areas), pneumotaxic area, and apneustic area.

Question 50

Role of the Respiratory Center

Respiratory mm. controlled by neurons in pons & medulla
3 groups of neurons
medullary rhy............
pne...............
apn............ centers

Answer 50

Role of the Respiratory Center

Respiratory mm. controlled by neurons in pons & medulla
3 groups of neurons
medullary rhythmicity
pneumotaxic
apneustic centers

Question 51

Medullary Rhythmicity Area

The function of the medullary rhythmicity area is to control the basic rhythm of respiration.
The inspiratory area has an intrinsic excita……. of autor………… neurons that sets the basic rhythm of respiration.
The expiratory area neurons remain ina……… during most qu…….. respiration but are probably activated during high levels of ventilation to cause contraction of muscles used in for…….. (labored) expiration.

Answer 51

Medullary Rhythmicity Area

The function of the medullary rhythmicity area is to control the basic rhythm of respiration.
The inspiratory area has an intrinsic excitability of autorhythmic neurons that sets the basic rhythm of respiration.
The expiratory area neurons remain inactive during most quiet respiration but are probably activated during high levels of ventilation to cause contraction of muscles used in forced (labored) expiration.

Question 52

Medullary Rhythmicity Area

Controls basic rhythm of respiration
Inspiration for …. seconds, expiration for …..
Autorhythmic cells active for ….. seconds then inactive
Expiratory neurons ina……. during most quiet breathing only active during h…… ventilation rates

Answer 52

Medullary Rhythmicity Area

Controls basic rhythm of respiration
Inspiration for 2 seconds, expiration for 3
Autorhythmic cells active for 2 seconds then inactive
Expiratory neurons inactive during most quiet breathing only active during high ventilation rates

Question 53

Pneumotaxic Area

The pneu………. area in the upper pons helps coor……… the transition between insp……… and expi……….
The apneustic area sends imp…… to the inspiratory area that activate it and prolong insp……., inhibiting expir…….

Answer 53

Pneumotaxic Area

The pneumotaxic area in the upper pons helps coordinate the transition between inspiration and expiration.
The apneustic area sends impulses to the inspiratory area that activate it and prolong inspiration, inhibiting expiration.

Question 54

Pneumotaxic Area

The pneumotaxic area in the upper pons helps coordinate the transition between in………… and e……………
The apn………. area sends impulses to the insp………. area that activate it and prolong inspiration, inhi…….. expiration.

Answer 54

Pneumotaxic Area

The pneumotaxic area in the upper pons helps coordinate the transition between inspiration and expiration.
The apneustic area sends impulses to the inspiratory area that activate it and prolong inspiration, inhibiting expiration.

Question 55

Regulation of Respiratory Center

Cortical Influences
voluntarily alter breathing patterns
Co………. influences allow con……….. control of respiration that may be needed to avoid inhaling noxious gas……. or water.
Voluntary breath holding is limited by the overriding stimuli of increased ……… and [CO2].
inspiratory center is stimulated by increase in either
if you hold breathe until you faint—-breathing will resume

Answer 55

Regulation of Respiratory Center

Cortical Influences
voluntarily alter breathing patterns
Cortical influences allow conscious control of respiration that may be needed to avoid inhaling noxious gasses or water.
Voluntary breath holding is limited by the overriding stimuli of increased [H+] and [CO2].
inspiratory center is stimulated by increase in either
if you hold breathe until you faint—-breathing will resume

Question 56

Chemoreceptor Regulation of Respiration

• A slight increase in PCO2 (and thus H+), a condition called hypercapnia, stimulates central chem…………….
  As a response to increased PCO2, increased … and decreased PO2, the inspiratory area is activated and hyperv………….., rapid and deep breathing, occurs.
  If arterial PCO2 is lower than ……. mm Hg, a condition called hypocapnia, the chemoreceptors are not stimulated and the inspiratory area sets its own pace until CO2 accumulates and PCO2 rises to …….. mm Hg.
  Severe deficiency of O2 depresses activity of the central chemoreceptors and respiratory center.

Answer 56

A slight increase in PCO2 (and thus H+), a condition called hypercapnia, stimulates central chemoreceptors.
As a response to increased PCO2, increased H+ and decreased PO2, the inspiratory area is activated and hyperventilation, rapid and deep breathing, occurs.
If arterial PCO2 is lower than 40 mm Hg, a condition called hypocapnia, the chemoreceptors are not stimulated and the inspiratory area sets its own pace until CO2 accumulates and PCO2 rises to 40 mm Hg.
Severe deficiency of O2 depresses activity of the central chemoreceptors and respiratory center

Question 57

Chemical Regulation Of Respiration

Central chemoreceptors in me........
respond to changes in ....... or pCO2
hypercapnia = slight in......... in pCO2 is noticed
Peripheral chemoreceptors
respond to changes in H+ , pO2 or PCO2
aortic body---in wall of aorta
nerves join va........
carotid bodies--in walls of common carotid art.........
nerves join glos................ nerve

Answer 57

Chemical Regulation of Respiration

Central chemoreceptors in medulla
respond to changes in H+ or pCO2
hypercapnia = slight increase in pCO2 is noticed
Peripheral chemoreceptors
respond to changes in H+ , pO2 or PCO2
aortic body---in wall of aorta
nerves join vagus
carotid bodies--in walls of common carotid arteries
nerves join glossopharyngeal nerve

Question 58

Negative Feedback Regulation of Breathing

Negative feedback control of breathing
Increase in a.......... pCO2
Stim......... receptors
Inspiratory ce...........
Muscles of re.......... contract more frequently & forcefully
pCO2 Dec............

Answer 58

Negative Feedback Regulation of Breathing

Negative feedback control of breathing
Increase in arterial pCO2
Stimulates receptors
Inspiratory center
Muscles of respiration contract more frequently & forcefully
pCO2 Decreases

Question 59

Control of Respiratory Rate

Proprioceptors of joints and muscles activate the inspiratory center to increase ven........... prior to exercise induced ox........... need.
The inflation (Hering-Breuer) reflex detects lung expansion with stretch rece.......... and limits it depending on ventilatory need and prevention of damage.
Other influences include bl......... pressure, limbic system, tem............, pain, stretching the anal sphi........, and irritation to the resp............. mucosa.

Answer 59

Control of Respiratory Rate

Proprioceptors of joints and muscles activate the inspiratory center to increase ventilation prior to exercise induced oxygen need.
The inflation (Hering-Breuer) reflex detects lung expansion with stretch receptors and limits it depending on ventilatory need and prevention of damage.
Other influences include blood pressure, limbic system, temperature, pain, stretching the anal sphincter, and irritation to the respiratory mucosa.

Question 60

Hypoxia

Hypoxia refers to oxygen deficiency at the tissue level and is classified in several ways (Clinical Application).

Hypoxic hyp……… is caused by a low P……. in art…….. blood (high altitude, airway obstruction, fluid in lungs).

In anaemic hypoxia, there is too little functioning he………. in the blood (hemorrhage, anemia, carbon monoxide poisoning).

Stagnant hypoxia results from the inability of blood to carry oxyg….. to tiss……….. fast enough to sustain their ne…….. (heart failure, circulatory shock).

In histotoxic hypoxia, the blood delivers adequate ox……… to the tissues, but the tissues are una….. to use it properly (c……… poisoning).

Answer 60

Hypoxia

Hypoxia refers to oxygen deficiency at the tissue level and is classified in several ways (Clinical Application).
Hypoxic hypoxia is caused by a low PO2 in arterial blood (high altitude, airway obstruction, fluid in lungs).
In anaemic hypoxia, there is too little functioning hemoglobin in the blood (hemorrhage, anemia, carbon monoxide poisoning).
Stagnant hypoxia results from the inability of blood to carry oxygen to tissues fast enough to sustain their needs (heart failure, circulatory shock).
In histotoxic hypoxia, the blood delivers adequate oxygen to the tissues, but the tissues are unable to use it properly (cyanide poisoning).

Question 61

EXERCISE AND THE RESPIRATORY SYSTEM

The respiratory system works with the cardiovascular system to make appropriate adjustments for different exercise inte……… and durations.
As blood flow incr……. with a lower …….. and higher ………… content, the amount passing through the lung (pulmonary perfusion) increases and is matched by increased venti……….. and oxygen diffusion ca……… as more pulmonary capillaries open.
Ventilatory modifications can increase 30 times above resting levels, in an initial rapid rate due to neu….. influences and then more gradually due to chemical stimulation from changes in cell metabolism. A similar, but reversed, effect occurs with cessation of exercise.
Smokers have difficulty breathing for a number of reasons, including nicotine, mucous, irritants, and that fact that scar tissue replaces elastic ………..

Answer 61

EXERCISE AND THE RESPIRATORY SYSTEM

The respiratory system works with the cardiovascular system to make appropriate adjustments for different exercise intensities and durations.
As blood flow increases with a lower O2 and higher CO2 content, the amount passing through the lung (pulmonary perfusion) increases and is matched by increased ventilation and oxygen diffusion capacity as more pulmonary capillaries open.
Ventilatory modifications can increase 30 times above resting levels, in an initial rapid rate due to neural influences and then more gradually due to chemical stimulation from changes in cell metabolism. A similar, but reversed, effect occurs with cessation of exercise.
Smokers have difficulty breathing for a number of reasons, including nicotine, mucous, irritants, and that fact that scar tissue replaces elastic fibers.

Question 62

Smokers Lowered Respiratory Efficiency

Smoker is easily “winded” with moderate exercise
nicotine constricts terminal br…………
carbon monoxide in smoke binds to hem……..
irritants in smoke cause excess mu…… secr………..
ir……….. inhibit movements of cilia
in time destroys elastic fib….. in lungs & leads to e…………
trapping of air in alveoli & reduced gas exc……….

Answer 62

Smokers Lowered Respiratory Efficiency

Smoker is easily “winded” with moderate exercise
nicotine constricts terminal bronchioles
carbon monoxide in smoke binds to hemoglobin
irritants in smoke cause excess mucus secretion
irritants inhibit movements of cilia
in time destroys elastic fibers in lungs & leads to emphysema
trapping of air in alveoli & reduced gas exchange

Question 63

Hyperbaric pressure

As water is incompressible the tissues of the body are reasonably protected from external pressures
Air-filled spaces e.g. lungs, respiratory passages, middle ear and other sinuses will be affected by pressure changes
At a depth of 30m and deeper the volume of air in the lungs becomes so small that the chest begins to collapse under the forces of am,,,,,,,,, pressure
This is also true for the ear,,,,,,, (middle ear) and other air filled spaces. Fluid and blood will move into the v,,,,,,,,,,, created.

Answer 63

Hyperbaric pressure

As water is incompressible the tissues of the body are reasonably protected from external pressures
Air-filled spaces e.g. lungs, respiratory passages, middle ear and other sinuses will be affected by pressure changes
At a depth of 30m and deeper the volume of air in the lungs becomes so small that the chest begins to collapse under the forces of ambient pressure
This is also true for the eardrum (middle ear) and other air filled spaces. Fluid and blood will move into the vacuum created.

Question 64

Nitrogen narcosis

A diver must breathe air or other gases at inc……… pressure to equ……… the increased pre………. on the chest wall and abdomen
CO2 is routinely removed to prevent its accumulation
100% O2 at an increased pressure causes CNS symptoms of ……. toxicity (therefore reduced to 20% or less)
If a diver breathes compressed air the increased PN2 can cause nit………. nar……… or ‘rapture of the deep’
At 4-5 atm (30-40m) 80% N2 produces a definite eup………
At greater pressures, the symptoms resemble alcohol intoxi…………..
This problem can be avoided by breathing mixtures of O2 and helium…however, this can cause high pressure neur…….. syndrome, HPNS, during a deep dive (drowsiness, tremors and impaired manual dexterity).

Answer 64

Nitrogen narcosis

A diver must breathe air or other gases at increased pressure to equalise the increased pressure on the chest wall and abdomen
CO2 is routinely removed to prevent its accumulation
100% O2 at an increased pressure causes CNS symptoms of O2 toxicity (therefore reduced to 20% or less)
If a diver breathes compressed air the increased PN2 can cause nitrogen narcosis or ‘rapture of the deep’
At 4-5 atm (30-40m) 80% N2 produces a definite euphoria
At greater pressures, the symptoms resemble alcohol intoxification
This problem can be avoided by breathing mixtures of O2 and helium…however, this can cause high pressure neurological syndrome, HPNS, during a deep dive (drowsiness, tremors and impaired manual dexterity).

Question 65

Decompression sickness

When a diver breathing 80% N2 ascends from a dive, alv…….. PN2 falls and N2 diffuses from the tissues into the blood and then into the lungs
If decompression is gradual no harmful effects are observed
However, in a rapid ascent N2 escapes from solution i.e. it ‘bubbles’ to cause the b……. (severe pains in the joints, paresthesia and itching, obstruction of arteries in the brain leading to pa……….. and respiratory failure)
Treatment involves prompt recompr………… followed by slow decom…………..

Answer 65

Decompression sickness

When a diver breathing 80% N2 ascends from a dive, alveolar PN2 falls and N2 diffuses from the tissues into the blood and then into the lungs
If decompression is gradual no harmful effects are observed
However, in a rapid ascent N2 escapes from solution i.e. it ‘bubbles’ to cause the bends (severe pains in the joints, paresthesia and itching, obstruction of arteries in the brain leading to paralysis and respiratory failure)
Treatment involves prompt recompression followed by slow decompression

Question 66

Air embolism

A diver breathing from a tank at increased pre……….. holds his breath and rises to the surface
The gas in the lungs expands and dr……. the air into the blood ves…… (air embolism)
This can occur during a rapid ascent from as shallow a depth as 5m
This can also occur as a result of rapid expan……. of gas in the lungs when external press……… is suddenly reduced from atmospheric to sub-atmospheric i.e. when the wall of a press……… ca……… of an airplane at altitude is breached.

Answer 66

Air embolism

A diver breathing from a tank at increased pressure holds his breath and rises to the surface
The gas in the lungs expands and drives the air into the blood vessels (air embolism)
This can occur during a rapid ascent from as shallow a depth as 5m
This can also occur as a result of rapid expansion of gas in the lungs when external pressure is suddenly reduced from atmospheric to sub-atmospheric i.e. when the wall of a pressurised cabin of an airplane at altitude is breached.

Question 67

Hypobaric pressure

As altitude increases the partial pressure of the constituent gases ↓ (although the relative amount of gases remains the s…………)
↑ altitude is also accompanied by a ↓ in air de…….., tem……… and relative hu………..
A ↓ PO2 has implications for the loading of respiratory pig…………

Answer 67

Hypobaric pressure

As altitude increases the partial pressure of the constituent gases ↓ (although the relative amount of gases remains the same)
↑ altitude is also accompanied by a ↓ in air density, temperature and relative humidity
A ↓ PO2 has implications for the loading of respiratory pigments

Question 68

Responses to altitude

Hyperventilation (short-term) – sensory receptors detect a ↓ in …………. levels in the blood and stimulate an increase in tidal vol………. (↑ arterial PO2 but ↓ PCO2)
Alkalosis (long-term) – hyperventilation causes a respiratory alkalosis
Increased excretion of H………- in the kidney (long-term) – helps control any alk……….

Answer 68

Responses to altitude

Hyperventilation (short-term) – sensory receptors detect a ↓ in oxygen levels in the blood and stimulate an increase in tidal volume (↑ arterial PO2 but ↓ PCO2)
Alkalosis (long-term) – hyperventilation causes a respiratory alkalosis
Increased excretion of HCO3- in the kidney (long-term) – helps control any alkalosis

Question 69

Acute Mountain Sickness

A rapid ascent to high altitude brings about AMS
Characterised by nausea, tachycardia, insomnia, dyspnea, muscle weakness, oedema in legs/feet, anorexia, dizziness
Treatment involves rest, aspirin, fluid replacement…also acetazolamide (di…….) is effective in reducing the incidence/sev………. of AMS (it ↑ blood CO2 and ↓ blood pH) or use of the Gamow bag

Answer 69

Acute Mountain Sickness

A rapid ascent to high altitude brings about AMS
Characterised by nausea, tachycardia, insomnia, dyspnea, muscle weakness, oedema in legs/feet, anorexia, dizziness
Treatment involves rest, aspirin, fluid replacement…also acetazolamide (diamox) is effective in reducing the incidence/severity of AMS (it ↑ blood CO2 and ↓ blood pH) or use of the Gamow bag