Chapter 23: The Respiratory System

Question 1

Describe the difference between the upper and lower respiratory system

Answer 1

Upper - nose, nasal sanity, pharynx, and associated structures
Lower - larynx, trachea, bronchi, and lungs

Question 2

Describe the functional differences between the conducting and respiratory zone

Answer 2

Conducting - consists of a series of interconnecting cavities and tubes both outside and within the lungs; function is is filter, warm, and moisten air and conduct it to the lungs

Respiratory - consists of tubes and tissues within the lungs where gas exchange occurs; the main sites of gas exchange between air and blood

Question 3

What is the pharynx?

Answer 3

The throat

A funnel-shaped tube that starts at the internal nares and extends to the level of the cricoid cartilage, the most interior cartilage of the larynx (voice box)

Wall is composed of skeletal muscles and is lined with a mucous membrane

Has 3 anatomical regions: nasopharynx, oropharynx, laryngopharynx

Question 4

Describe the following components of the nose: external nares, internal nares, nasal cavity, vestibule, septum, superior/middle/inferior meatuses, and olfactory epithelium

Answer 4

External nares (nostrils)

Internal nares (choanae) - two openings where the nasal cavity communicates with the pharynx

Nasal cavity - space in the anterior aspect of skill that lies inferior to the nasal bone and superior to oral cavity; lined with muscle and mucous membrane

Vestibule - anterior portion of the nasal cavity just inside the nostrils

Septum - divides the nasal cavity into right and left sides; consist of hyaline cartilage

Superior/middle/ingerior meatuses - grovelike air passageways linked with mucous membranes that warms and moistens the air

Olfactory epithelium - olfactory receptor cells, supporting cells, and basal cells in the superior nasal conchae and adjacent septum (cilia but no goblet cells)

Question 5

Describe the following components of the pharynx: nasopharynx, soft palate, eustachian tubes, pharyngeal tonsil, oropharynx, faucet, palatine and lingual tonsils, and laryngopharynx

Answer 5

Nasopharynx (superior) - lies posterior to the nasal cavity and extends to the soft palate

Soft palate - forms the posterior portion of the roof of the mouth, an arch-shaped muscular partition between nasopharynx and oropharynx that has 5 openings in its wall

Eustachian tubes - 2 openings in soft palate that lead into the auditory tubes

Pharyngeal tonsil (adenoid) - on the posterior wall of the soft palate

Oropharynx (intermediate) - lies posterior to the oral cavity and extends from soft palate inferiorly to level of hyoid bone

Faucet - the opening in the oropharynx that leads to the mouth

Palatine and lingual tonsils - two pairs of tonsils found in the oropharynx

Laryngopharynx (inferior) - begins at level of the hyoid bone and end opens into the esophagus posteriorly and the larynx anteriorly

Question 6

What is the larynx?

Answer 6

Voice box - short passageway that connects the laryngopharynx with the trachea; lies in the middle of the neck anterior to the esophagus and the 4-6 cervical vertebrae

The wall is composed of 9 pieces of cartilage

Question 7

Describe the following components of the larynx: thyroid cartilage, epiglottis, glottis, cricoid cartilage, arytenoid cartilage

Answer 7

Thyroid cartilage (adam’s apple) - 2 fused plates of hyaline cartilage that form the inner form of the anterior wall of larynx and give it a triangular shape

Epiglottis - large leaf-shaped piece of elastic cartilage that is covered with epithelium; stem is attached to rim of thyroid cartilage and lead portion is unattached and moves up and down like a trap door closing off the glottis

Glottis - pair of folds of mucous membrane, the vocal folds, and the space between them called the rima glottidis; when entered the ‘wrong hole’ effect

Cricoid cartilage - ring of hyaline cartilage that forms the inferior wall of the larynx; landmark for making an emergency tracheotomy

Arytenoid cartilage - paired triangular pieces of mostly hyaline cartilage located as the posterior, superior border of the cricoid cartilage

Question 8

What are the structures involved in voice production

Answer 8

The mucous membrane of the larynx forms the superior vestibular folds (false vocal cords) and the inferior vocal folds (true vocal cords)

Vocal folds are bands of elastic ligaments stretched between the rigid cartilages of the larynx

Intrinsic laryngeal muscles attached the rigid cartilages and when they contract they move the cartilage, which pulls the elastic ligaments tight, narrowing the rima glottidis (space)

Contraction of posterior cricarytenoid muscles cause abduction (opening) and contraction of lateral cricarytenoid muscles cause adduction (closing)

When air passes through phonation (vibration) occurs and pitch depends on the tension of the vocal cords

Question 9

What is the trachea?

Answer 9

Windpipe - rubular passageway for air that is located anterior to the esophagus and extends from larynx to the superior border of T5 where it divides into the right and left primary bronchi

The layers of the wall from deep to superficial are the mucosa, submucosa, hyaline cartilage (C rings felt on throat), and adventitia (areolar connective tissue)

Question 10

What are the differences between the right and left bronchi?

Answer 10

Right - goes into right lung, more vertical, shorter and wider

Left - goes into left lung

Question 11

Describe the following components of the bronchi: carina, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles, bronchial tree

Answer 11

Carina - an internal ridge where the trachea divides into the right and left main bronchi; has a very sensitive mucous membrane for triggering a cough reflex

Secondary (lobar) bronchi - main bronchi divide to from smaller bronchi, one for each lobe (3 for right and 2 for left)

Tertiary (segmental) bronchi - further branching that supply specific bronchopulmonary segments within the lobes

Bronchioles - the division of tertiary bronchi that further divide into terminal bronchioles

Bronchial tree - the extensive branching from trachea to terminal bronchioles resembles and inverted tree

Question 12

Each lung is enclosed and protected by a double-layered serous membrane called the ______ membrane

Answer 12

Pleural

Question 13

Describe the 2 layers of the pleural membrane

Answer 13

Parietal (superficial) pleura lines the wall of the thoracic cavity

Visceral (deep) pleura covers the lungs themselves

Between the layers is a small space called the pleural cavity, which contains lubricated fluid to reduce friction

Question 14

The apex of the lung refers to the narrow inferior portion

True or False

Answer 14

False - the apex refers to the superior narrow portion and the base refers to the broad inferior portion

Question 15

What is the hilum? is it located in the costal surface or mediastinal surface of the lung?

Answer 15

Hilum is a region through which bronchi, pulmonary blood vessels, lymphatic vessels, and nerves enter and exit

It is located in the mediastinal surface of the lung (costal lies against ribs)

Question 16

What is the root of the lung?

Answer 16

Pleura and connective tissue that hold together the hilum

Question 17

Define cardiac notch

Answer 17

Where the apex of the heart lies

Causes the left lung to be 10% smaller than the right

Question 18

Where are the oblique and horizontal fissures found in the lungs?

Answer 18

Oblique - externes inferiorly and anteriorly and found in both lungs

• Separates the superior and inferior lobes in left lung
• Separates the inferior from both the superior and middle lobe in right lung

Horizontal - found only in the right lung

Question 19

Each bronchopulmonary segment of the lung has small compartments called lobules, what do they contain?

Answer 19

1. Lympthatic vessel
2. Arteriole
3. Venule
4. Branch from a terminal bronchiole (that subdivide into respiratory bronchioles)

Question 20

What are alveolar ducts?

Answer 20

The subdivision of respiratory bronchioles (2-11)

Question 21

What is an alveolar sac?

Answer 21

Sac that consists of 2+ alveoli that share a common opening

An alvelous is a cup-shaped out pouching lined by simple squamous epithelium and supported by a thin elastic basement membrane

Question 22

What is the difference between type I and type II alveolar cells?

Answer 22

Type I - more numerous; simple squamous epithelial cells that form a nearly continuous linking of the alveolar wall; main site of gas exchange

Type II (septal cells) - found between type I cells; rounded or cuboidal epithelial cells with free surfaces containing microvilli that secrete fluid and surfactant which keeps the surfaces between cells moist

*surfacant reduces surface tension of alveolar fluid, reducing tendency of alveoli to collapse

Question 23

What are alveolar macrophages?

Answer 23

aka dust cells that remove fine dust particles and other debris from the alveolar spaces

Question 24

Which arteries do lungs receive blood from?

Answer 24

Pulmonary and bronchial arteries

Deoxygenated blood passes through the pulmonary trunk, which divides into a left pulmonary artery that enters the left lung and a right pulmonary arty that enters the right lung

Question 25

After becoming oxygenated where do the pulmonary veins return blood to?

Answer 25

left atrium

Question 26

Describe the 3 steps of respiration

Answer 26

1. Pulmonary ventilation (breathing) - inhalation and exhalation of air and involves the exchange of air and the alveoli of the lungs
2. External (pulmonary) respiration - exchange of gases between alveoli and the blood in pulmonary capillaries across the respiratory membrane; blood gains O2 and loses CO2
3. Internal (tissue) respiratory - exchange of gases between blood in systemic capillaries and tissue cells; blood looses O2 and gains CO2

Question 27

How does pressure change during inhalation?

Answer 27

In order for air to flow into the lungs, the pressure inside the alveoli must become lower than the atmospheric pressure which is achieved by increasing the size of the lungs - the diagphragm and external intercostals contract and expand the chest cavity

As the chest expands the alveolar pressure inside the lungs drops and air flows from a region of higher pressure to a region of lower pressure, causing inhalation

This inverse relationship between volume and pressure is called Boyle’s law - same # of molecules in a larger space, decreases volume

Question 28

What is intrapleural pressure?

Answer 28

The pressure between the two pleural layers which during quiet inhalations is always sub atmospheric (lower than atmospheric pressure)

Question 29

How does pressure change during exhalation?

Answer 29

The diaphragm and external intercostals relax, the chest and lungs recoil, the chest cavity contracts, and the alveolar pressure increases above the atmospheric pressure

AS a result of the pressure difference, air flows out of the lungs and the lung volume decreases

Question 30

How does surface tension of alveolar fluid affects pulmonary ventilation?

Answer 30

surface tension arises at all air-water interfaces because the polar water molecules are more strongly attached to each other than they are to gas molecules in the air

during breathing, surface tension must be overcome to expand the lungs during each inhalation and all accounts for 2/3 of elastic recoil

Surfactant decreases surface tension and a deficiency can cause respiratory distress

Question 31

How does compliance of the lungs affects pulmonary ventilation?

Answer 31

Compliance refers to how much effort is required to stretch the lungs and chest wall

High compliance means they expand easily and low compliance means they resist expansion

Compliance is related to elasticity and surface tension

Question 32

How does airway resistance affects pulmonary ventilation?

Answer 32

Any condition that increases airway resistance so that more pressure is required to maintain that same airflow affects ventilation

Question 33

The term for the normal pattern of quiet breathing is ______

Answer 33

Eupnea

Question 34

A pattern of shallow (chest) breathing that consist of upward and outward movement of the chest due to contractions is called _______

Answer 34

coastal breathing

Question 35

A pattern of deep breathing (abdominal) that consists of the outward movement of the abdomen due to contractions is called _________

Answer 35

diaphragmatic breathing

Question 36

What is the different between tidal volume, inspiratory reserve volume, expiratory reserve volume and residual volume?

Answer 36

tidal volume - the volume of one breath

inspiratory reserve volume - the additional inhaled air that occurs when you take a deep breath

expiratory reserve volume - the additional exhaled air that occurs when you exhale forcibly

residual volume - even after a forceful exhale their is still residual air due to the subatompspheric intraplerual pressure that keeps alveoli slightly inflated, however, this volume cannot be measured

Question 37

What is minute ventilation (MV)?

Answer 37

the total volume of air inhaled and exhaled each minute multiple by the tidal volume (500 mL)

MV = 12 breaths/min x 500 ML/breath
= 6L/min

Question 38

What is the apparatus that measure the volume of exchanged air during breathing?

Answer 38

Spirometer

Question 39

Define anatomic dead space

Answer 39

The conducting airways with air that does not undergo respiratory exchange

About the same in mm as your ideal weight in lbs

Question 40

Define alveolar ventilation rate

Answer 40

The volume of air per minute that actually reaches the respiratory zone

Question 41

Differentiate among inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity

Answer 41

Inspiratory capacity - sum of tidal cove and inspiratory reserve volume

Functional residual capacity - sum of residual volume and expiratory reserve volume

Vital capacity - sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume

Total lunch capacity - sum of vital capacity and residual volume

Question 42

Describe Dalton’s law

Answer 42

Each gas in a mixture of gases exerts its own pressure as if no other gases were present

The pressure of a specific gas in a mixture is called its partial pressure (Px) and the total pressure of the mixture is calculated simply by adding all of the partial pressures

Question 43

Describe Henry’s law

Answer 43

The quantity of a gas that will dissolve in a liquid is proportional to the partial pressure of the gas and its solubility

The ability of a gas to stay in solution is greater when its partial pressure is higher and when it has a high solubility in water

If a scuba divers ascent is too rapid, nitrogen comes out of solution too quicklyy and forms gas bubbles in the tissues, resulting in decompression sickness

Question 44

Describe the exchange of oxygen and carbon dioxide in external respiration

Answer 44

External respiration (pulmonary gas exchange) is the diffusion of O2 from air in the alveoli to blood in pulmonary capillaries and the diffusion of CO2 in the opposite direction

It converts deoxygenated blood coming from the right side of the heart into oxygenated blood that returns to the left side of the heart

As blood flows it picks up O2 from alveolar air and unloads CO2 - gasses disuse from an area of higher partial pressure to lower partial pressure

Question 45

Describe the exchange of oxygen and carbon dioxide in external respiration

Answer 45

Internal respiration (systemic gas exchange) is the exchange of O2 and CO2 between system capillaries and tissue cells

The gases exchange in opposite directions as they move down their pressure gradient

Question 46

Describe how the blood transports oxygen and carbon dioxide

Answer 46

Oxygen: 1.5% is dissolved in plasma and 98.5% is bound to hemolongin in RBCs (Hb-02)
Hb (deoxyhemoglobin) + O2 Hb-O2 (oxyhemoglobin)

Carbon dioxide: 7% dissolved in plasma, 23% bound to hemoglobin in RBCs (HB-CO2), and 70% is transported as bicarbonate ions (HCO3-)
Hb + CO2 Hb-CO2 (carbaminohemoglobin)
CO2 + H2) H2CO3 (carbonic acid) H+ + HCO3 (bicarbonate ion)

Question 47

Describe the relationship between hemoglobin and oxygen partial pressure

Answer 47

The higher the partial pressure (P02), the more O2 combines with Hb

When Hb is covered to Hb-02 the hemoglobin in said to be fully saturated

The oxygen-hemoglobin dissociation curve demonstrates this relationship

Question 48

Describe how acidity (pH), partial pressure of CO2, temperature and BPG affect the affinity of hemoglobin for oxygen

Answer 48

Acidity - as acidity increases (pH decreases0 the affinity of hemoglobin for O2 decreases, and O2 dissociates more readily from hemoglobin; the unloading of O2 is enhanced and the dissociation curve shifts to the right so there is less Hb saturated with O2 a change known as the Bohr effect

PCO2 - as Co2 partial pressure rises, hemoglobin releases O2 more readily; related to pH as increased Pco2 causes decreased pH

Temperature - O2 release is increased from hemoglobin as temp rises

BPG - Increased BPG decreases the affinity of hemoglobin for O@, and thus helps unload O2 from hemoglobin

Question 49

What is the haldane effect?

Answer 49

The lower the amount of oxyhemoglobin, the higher the CO2 carrying capacity of the blood

2 characteristics of deoxyhemoglobin (Hb) give rise to this effect:

• Hb binds to and thus transports more CO2 than does Hb-O2
• Hb buffers more H+ than does Hb-O2, thereby removing H+ from solution and promoting conversation of CO2 to HCO3- via the reaction catalyzed by carbonic anhydrase

Question 50

What are the two principal areas of the respiratory centre?

Answer 50

Medullary respiratory center

Ventral respiratory center

Question 51

Describe the medullary respiratory center and its role in normal quiet breathing and forceful breathing

Answer 51

Made up of two collections of neurons called the dorsal respiratory group (DRG) and the ventral respiratory group (VRG)

Durning normal breathing the DRG cause eat contraction of diaphragm and external intercostal muscles to contract to cause normal quiet inhalation and then will relax for 3 seconds during normal quiet exhalation; VRG in inactive

During forceful breathing the DRG activates the VRG which causes the contraction of accessory muscles of inhalation to assist in forceful inhalation and the VRG also causes the contraction of accessory muscles of exhalation to assist in forceful exhalation

Question 52

Describe the role of the pontine respiratory group (PRG)

Answer 52

PRG is a collection of neurons in the pons that are active during inhalation and exhalation

They transmit nerve impulses to the DRG and play a role in modifying the basic rhythm of breathing generated by the VRG as when exercising, speaking or sleeping

Question 53

How can cortical influences affect breathing?

Answer 53

We can voluntarily alter our pattern of berating - however the ability not to breathe is limited by the buildup of CO2 and H+ in the body

Hypothalamus and limbic system can stimulate the respiratory center allowing emotional stimuli to alter breathing such as during laughing

Question 54

What are the roles of chemoreceptors in regulating breathing?

Answer 54

Central chemoreceptors are located near the medulla in the CNS and they respond to changes in H+ concentration or Pco2 or both in CSF

Peripheral chemoreceptors are located in aortic bodies (wall of the arch of aorta) and in carotid bodies (wall of L and R common carotid arteries where they divide into internal and external carotid arteries) in the peripheral nervous system and are sensitive to Po2, H+ and Pco2 in the blood

Question 55

Differentiate beween hypercapnia and hypocapnia

Answer 55

Hypercapnia - Pco2 higher than 40 mmHg stimulates central chemoreceptors to respond to increase H+; increase in Pco2, H+ and lack of O2 stimulates peripheral chemoreceptors; breathing begins to decrease or cease and chemoreceptors participate in negative feedback looks to cause hyperventilation allowing increase of O2 and decrease of Co2

Hypocapnia - Pco2 lower then 40 mmHg does not activate either central or peripheral chemoreceptor and DRG neurons set their own pace until CO2 accumulates and Pco2 rises back to 40mmHg

Question 56

What are propricepotors role in regulating breathing?

Answer 56

They stimulate DRG of medulla

This is why as soon as you start exercising your rate of depth of breathing may increase before changes in Po2, Pco2, or H+ occur

Question 57

What is the inflation reflex?

Answer 57

Baroreceptors (stretch receptors) are located in the walls of the bronchi and bronchioles and when activated during overinflation of lungs, impulses inhibit the DRG via the vagus nerve and the diaphragm and intercostals relax causing exhalation

Question 58

Describe how the following factors influence breathing: limbic system, temperature, pain, anal sprinter muscle, irritation of airways, blood pressure

Answer 58

Limbic system - limbic activation (excitation, anxiety) can send excitatory input to DRG causing increase rate and depth of breathign

Temp -breathing increases with increased body temp and vice versa

Pain - Sudden severe pain brings about brief apnea but prolonged somatic pain increased breathing

anal sprinter muscle stretching increases breathing rate

Irriation of airways causing immediate cessation of breathing

Blood pressure increase causes decreased breathing rate

Question 59

Describe the effects of exercise of the respiratory system

Answer 59

As cardiac output rises, the blood flow to the lungs, termed pulmonary percussion increases as well

In addition, the O2 diffusing capacit may increase threefold during maximal exercise because more pulmonary capillaries become maximally perfused

Question 60

Define asthma

Answer 60

A disorder characterized by chronic airway inflammation, airway hypersensitiviy, and airway obstruction

Question 61

Define chronic obstructer pulmonary disease (COPD)

Answer 61

chronic and recurrent obstruction of airflow, which increases airway resistance

Question 62

Define emphysema

Answer 62

Destruction of the walls of the alveoli, producing abrnoally large air spaces that remain filled with air during exhalation

O2 discussion is reduced and blood O2 is lowered

Question 63

Define chronic bronchitis

Answer 63

excessive secretion of bronchial mucous accompanied by a productive cough that lasts for at least 3 months of the year for 2 successive years

leading cause is cigarette smoking

Question 64

Define pneumonia

Answer 64

Acute infection of inflammation of the alveoli

Inflammation and edema cause the alveoli to fill with fluid, interfering with ventilation and gas exchange

Question 65

Define tuberculosis

Answer 65

Mycobacterium tuberculosis once inside the lungs multiplies and causes inflammation which stimulates neutrophils and macrophages to migrate to the area and engulf the bacteria to prevent their spread

Impaired immunity may enable the bacteria to escape into blood and lymph and affect other organs

Question 66

Define pulmonary edema

Answer 66

Abnormal accumulation of fluid in the ISF spaces and alveoli of the lungs that may arise from increased permeability of the pulmonary capillaries

Question 67

Define SIDS

Answer 67

sudden, unexpected death of an apparently healthy infant during sleep (2-4 months)

Linked to hypoxia

Question 68

Define SARS

Answer 68

Severe acute respiratory syndrome is an example of an emerging infectious disease - it is a respiratory illness caused by a new variety of coronavirus