1a1- chapter 22 respiratory system Flashcards Preview

Keiser A&P 1 > 1a1- chapter 22 respiratory system > Flashcards

Flashcards in 1a1- chapter 22 respiratory system Deck (235):
1

cardiopulmonary system

respiratory and cardiovascular systems work together to deliver oxygen to the tissues and remove carbon dioxide

2

collaborate to regulate the body’s acid base balance

respiratory system and the urinary system

3

Respiration has three meanings:

1.ventilation of the lungs (breathing)
2.the exchange of gases between the air and blood, and between blood and the tissue fluid
3.the use of oxygen in cellular metabolism

4

Functions of Respiratory System

•O2and CO2 exchange between blood and air
•speech and other vocalizations
•sense of smell
•affects pH of body fluids by eliminating CO2
•affects blood pressure by synthesis of vasoconstrictor, angiotensin II
•breathing creates pressure gradients between thorax and abdomen that promote the flow of lymph and venous blood
•breath-holding helps expel abdominal contents during urination, defecation, and childbirth(Valsalva maneuver)

5

Principal Organs of Respiratory System

nose, pharynx, larynx, trachea, bronchi, lungs
–incoming air stops in the alveoli

6

alveoli

•millions of thin-walled, microscopic air sacs
•exchanges gases with the bloodstream through the alveolar wall, and then flows back out

7

conducting division of the respiratory system

–those passages that serve only for airflow
–no gas exchange
–nostrils through major bronchioles

8

respiratory division of the respiratory system

–consists of alveoli and other gas exchange regions

9

upper respiratory tract

in head and neck
–nose through larynx

10

lower respiratory tract

organs of the thorax
–trachea through lungs

11

functions of the nose

–warms, cleanses, and humidifies inhaled air
–detects odors in the airstream
–serves as a resonating chamber that amplifies the voice

12

nose extends from

nostrils(nares), to a pair of posterior openings called the posterior nasal apertures (choanae)

13

facial part is shaped by

bone and hyaline cartilage
–superior half nasal bones and maxillae
–inferior half lateral and alar cartilages

14

ala nasi

flared portion at the lower end of nose shaped by alar cartilages and dense connective tissue

15

nasal fossae

right and left halves of the nasal cavity

16

nasal septum

divides nasal cavity
•composed of bone and hyaline cartilage
•vomer forms inferior part
•perpendicular plate of ethmoid forms superior part
•septal cartilage forms anterior part

17

roof and floor of nasal cavity

•ethmoid and sphenoid bones form the roof
•hard palate forms floor
–separates the nasal cavity from the oral cavity and allows you to breathe while you chew food
•paranasal sinuses and nasolacrimal duct drain into nasal cavity

18

vestibule

beginning of nasal cavity –small dilated chamber just inside nostrils
–lined with stratified squamous epithelium

19

vibrissae

stiff guard hairs that block insects and debris from entering nose

20

nasal conchae

superior, middle, and inferior nasal conchae (turbinates)
•project from lateral walls toward septum
•meatus–narrow air passage beneath each concha
•narrowness and turbulence insure that most air contacts mucous membranes
•cleans, warms, and moistens the air

21

olfactory epithelium

detect odors
–covers a small area of the roof of the nasal fossa and adjacent parts of the septum and superior concha
–ciliated pseudostratified columnar epithelium with goblet cells
–immobile cilia to bind odorant molecules

22

respiratory epithelium

lines rest of nasal cavity except vestibule
–ciliated pseudostratified columnar epithelium with goblet cells
–cilia are motile
–goblet cells secrete mucus and cilia propel the mucous posteriorly toward pharynx
–swallowed into digestive tract

23

erectile tissue

extensive venous plexus in inferior concha
–every 30 to 60 minutes, erectile tissue on one side swells with blood
–restricts air flow through that fossa
–most air directed through other nostril and fossa
–allowing engorged side time to recover from drying
–preponderant flow of air shifts between the right and left nostrils once or twice an hour

24

Nasal septum

3 parts

Perpendicular plate
Septal cartilage
Vomer

25

Pharynx:

3 regions

Nasopharynx
Oropharynx
Laryngopharynx

26

pharynx

pharynx(throat) –a muscular funnel extending about 13 cm (5 in.) from the choanae to the larynx

27

nasopharynx

•posterior to nasal apertures and above soft palate
•receives auditory tubes and contains pharyngeal tonsil
•90downward turn traps large particles (>10m)

28

oropharynx

•space between soft palate and epiglottis
•contains palatine tonsils

29

laryngopharynx

•epiglottis to cricoid cartilage
•esophagus begins at that point

30

nasopharynx passes only

air and is lined by pseudostratified columnar epithelium

31

oropharynx and laryngopharynxpass

air, food, and drink and are lined by stratified squamous epithelium

32

larynx

(voice box) –cartilaginous chamber about 4 cm (1.5 in.)

33

larynx

primary function

is to keep food and drink out of the airway
–has evolved to additional role –phonation –production of sound

34

phonation

production of sound

35

epiglottis

flap of tissue that guards the superior opening of the larynx
–at rest, stands almost vertically
–during swallowing, extrinsic muscles of larynx pull larynx upward
–tongue pushes epiglottis down to meet it
–closes airway and directs food to the esophagus behind it

36

vestibular folds

of the larynx play greater role in keeping food and drink out of the airway

37

nine cartilages that make up framework of larynx

epiglottic cartilage
thyroid cartilage
cricoid cartilage
arytenoid cartilages (2)
corniculate cartilages (2)
cuneiform cartilages (2

38

epiglottic cartilage

spoon-shaped supportive plate in epiglottis most superior one

39

thyroid cartilage

largest, laryngeal prominence (Adam’s apple) shield-shaped
•testosterone stimulated growth, larger in males

40

cricoid cartilage

connects larynx to trachea, ringlike

41

arytenoid cartilages (2)

posterior to thyroid cartilage

42

corniculate cartilages (2)

attached to arytenoid cartilages like a pair of little horns

43

cuneiform cartilages (2

support soft tissue between arytenoids and epiglottis

44

Walls of Larynx

walls of larynx are quite muscular
interior wall has two folds on each side that extend from thyroid cartilage in front to arytenoid cartilages in the back

45

superior vestibular folds

play no role in speech
•close the larynx during swallowing

46

inferior vocal cords

•produce sound when air passes between them
•contain vocal ligaments
•covered with stratifies squamous epithelium
–best suited to endure vibration and contact between the cords

47

glottis

the vocal cords and the opening between them

48

Action of Vocal Cords

intrinsic muscles control the vocal cords

49

loudness

determined by the force of air passing between the vocal cords

50

crude sounds

vocal cords produce crude sounds that are formed into words by actions of pharynx, oral cavity, tongue, and lips

51

trachea

trachea(windpipe) –a rigid tube about 12 cm (4.5 in.) long and 2.5 cm (1 in.) in diameter
–found anterior to esophagus
–supported by 16 to 20 C-shaped rings of hyaline cartilage
–reinforces the trachea and keeps it from collapsing when you inhale

52

trachealis muscle

spans opening in rings
•gap in C allows room for the esophagus to expand as swallowed food passes by
•contracts or relaxes to adjust air flow

53

inner lining of trachea is

ciliated pseudostratified columnar epithelium
–composed mainly of mucus-secreting cells, ciliated cells, and stem cells

54

mucociliary escalator

mechanism for debris removal
•mucus traps inhaled particles
•upward beating cilia drives mucus toward pharynx where it is swallowed

55

carina

internal medial ridge in the lowermost tracheal cartilage
•directs the airflow to the right and left

56

tracheostomy

to make a temporary opening in the trachea inferior to the larynx and insert a tube to allow airflow

57

lung

conical organ with a broad, concave base, resting on the diaphragm, and a blunt peak called the apex projecting slightly above the clavicle

58

costal surface

pressed against the ribcage

59

mediastinal surface

faces medially toward the heart

60

hilum

slit through which the lung receives the main bronchus, blood vessels, lymphatics and nerves

61

root of the lung

main bronchus, blood vessels, lymphatics and nerves

62

right lung

shorter than left because the liver rises higher on the right

63

right lung

has three lobes

superior, middle, and inferior separated by horizontal and oblique fissure

64

left lung

•taller and narrower because the heart tilts toward the left and occupies more space on this side of mediastinum
•has indentation –cardiac impression

65

cardiac impression

indentation in left lung

66

left lung

has two lobes

superior and inferior separated by a single oblique fissure

67

bronchial tree

a branching system of air tubes in each lung
–from main bronchus to 65,000 terminal bronchioles

68

main (primary) bronchi

supported by c-shaped hyaline cartilage rings

69

rt. main bronchus

bronchusis a 2-3 cm branch arising from fork of trachea
•right bronchus slightly wider and more vertical than left
•aspirated(inhaled) foreign objects lodge right bronchus more often the left

70

aspirated

inhaled

71

lt. main bronchus

is about 5 cm long
•slightly narrower and more horizontal than the right

72

lobar (secondary) bronchi

supported by crescent shaped cartilage plates

73

three rt. lobar(secondary) bronchi

superior, middle, and inferior
–one to each lobe of the right lung

74

two lt. lobar bronchi

superior and inferior
–one to each lobe of the left lung

75

segmental (tertiary) bronchi

supported by crescent shaped cartilage plates
–10 on right, and 8 on left

76

bronchopulmonary segment

functionally independent unit of the lung tissue

77

all bronchi are lined with

ciliated pseudostratified columnar epithelium
–cells grow shorter and the epithelium thinner as we progress distally

78

lamina propria

has an abundance of mucous glands and lymphocyte nodules (bronchus-associated lymphoid tissue, BALT)
•positioned to intercept inhaled pathogens

79

BALT

bronchus-associated lymphoid tissue

80

all divisions of bronchial tree have a large amount of

elastic connective tissue
•contributes to the recoil that expels air from lungs

81

muscularis mucosae

mucosa also has a well-developed layer of smooth muscle
•muscularis mucosae which contracts or relaxes to constrict or dilate the airway, regulating air flow

82

pulmonary artery

branches closely follow the bronchial tree on their way to the alveoli

83

bronchial artery

services bronchial tree with systemic blood
•arises from the aorta

84

bronchioles

–lack cartilage
–1 mm or less in diameter

85

pulmonary lobule

portion of lung ventilated by one bronchiole
–have ciliated cuboidal epithelium
–well developed layer of smooth muscle
–divides into 50 -80 terminal bronchioles

86

terminal bronchioles

final branches of conducting division
•measure 0.5 mm or less in diameter
•have no mucous glands or goblet cells
•have cilia that move mucus draining into them back by mucociliary escalator
•each terminal bronchiole gives off two or more smaller respiratory bronchioles

87

respiratory bronchioles

beginning of the respiratory division since alveoli participate in gas exchange
have alveoli budding from their walls

88

respiratory bronchioles

divide into

divide into 2-10 alveolar ducts
•end in alveolar sacs –grape-like clusters of alveoli arrayed around a central space called the atrium

89

Path of Air Flow

nasal cavity, pharynx, larynx, trachea, main bronchus, lobar bronchus, segmental bronchus, bronchiole, terminal bronchiole,{respiratory division}, respiratory bronchiole, alveolar duct, atrium, alveolus

90

Alveoli

150 million alveoli in each lung, providing about 70 m2of surface for gas exchange

91

cells of the alveolus

squamous (type I) alveolar cells
great (type II) alveolar cells
alveolar macrophages (dust cells)

92

squamous (type I) alveolar cells

thin, broad cells that allow for rapid gas diffusion between alveolus and bloodstream
•cover 95% of alveolus surface area

93

great (type II) alveolar cells

•round to cuboidal cells that cover the remaining 5% of alveolar surface
•repair the alveolar epithelium when the squamous (type I) cells are damaged
•secrete pulmonary surfactant

94

alveolar macrophages (dust cells)

most numerous of all cells in the lung
•wander the lumen and the connective tissue between alveoli
•keep alveoli free from debris by phagocytizing dust particles
•100 million dust cells perish each day as they ride up the mucociliary escalator to be swallowed and digested with their load of debris

95

pulmonary surfactant

a mixture of phospholipids and proteins that coats the alveoli and prevents them from collapsing when we exhale

96

respiratory membrane

the barrier between the alveolar air and blood

97

respiratory membrane consists of:

–squamous alveolar cells
–endothelial cells of blood capillary
–their shared basement membrane

98

visceral pleura

serous membrane that covers lungs

99

parietal pleura

adheres to mediastinum, inner surface of the rib cage, and superior surface of the diaphragm

100

pleural cavity

potential space between pleurae
normally no room between the membranes, but contains a film of slippery pleural fluid

101

functions of pleurae and pleural fluid

–reduce friction
–create pressure gradient
•lower pressure than atmospheric pressure and assists lung inflation
–compartmentalization
•prevents spread of infection from one organ in the mediastinum to others

102

breathing

(pulmonary ventilation) –consists of a repetitive cycle one cycle of inspiration(inhaling) and expiration(exhaling)

103

respiratory cycle

one complete inspiration and expiration

104

quiet respiration

while at rest, effortless, and automatic

105

forced respiration

deep rapid breathing, such as during exercise

106

flow of air in and out of lung depends on

a pressure difference between air pressure within lungs and outside body

107

breathing muscles

change lung volumes and create differences in pressure relative to the atmosphere

108

Respiratory Muscles

diaphragm
internal and external intercostal muscles
scalenes

109

diaphragm

–prime mover of respiration
–contraction flattens diaphragm and enlarging thoracic cavity and pulling air into lungs
–relaxation allows diaphragm to bulge upward again, compressing the lungs and expelling air
–accounts for two-thirds of airflow

110

internal and external intercostal muscles

–synergist to diaphragm
–between ribs
–stiffen the thoracic cage during respiration
–prevents it from caving inward when diaphragm descends
–contribute to enlargement and contraction of thoracic cage
–adds about one-third of the air that ventilates the lungs

111

scalenes

–synergist to diaphragm
–quiet respiration holds ribs 1 and 2 stationary

112

accessory muscles of respiration act mainly

in forced respiration

113

forced inspiration

–erector spinae, sternocleidomastoid, pectoralis major, pectoralis minor, and serratus anterior muscles and scalenes
–greatly increase thoracic volume

114

normal quiet expiration

–an energy-saving passive process achieved by the elasticity of the lungs and thoracic cage
–as muscles relax, structures recoil to original shape and original (smaller) size of thoracic cavity, results in air flow out of the lungs

115

forced expiration

–rectus abdominis, internal intercostals, other lumbar, abdominal, and pelvic muscles
–greatly increased abdominal pressure pushes viscera up against diaphragm increasing thoracic pressure, forcing air out

116

Valsalva maneuver

consists of taking a deep breath, holding it by closing the glottis, and then contracting the abdominal muscles to raise abdominal pressure and pushing organ contents out
–childbirth, urination, defecation, vomiting

117

Neural Control of Breathing
innervation

–fibers of phrenic nerve supply diaphragm
–intercostal nerves supply intercostal muscles

118

Brainstem Respiratory Centers

automatic, unconscious cycle of breathing is controlled by three pairs of respiratory centers in the reticular formation of the medulla oblongata and the pons

119

respiratory nuclei in medulla

ventral respiratory group (VRG)
dorsal respiratory group (DRG)

120

ventral respiratory group (VRG

•primary generator of the respiratory rhythm
•inspiratory neurons in quiet breathing (eupnea) fire for about two seconds
•expiratory neurons in eupnea fire for about three seconds allowing inspiratory muscles to relax
•produces a respiratory rhythm of 12 breaths per minute

121

dorsal respiratory group (DRG

•modifies the rate and depth of breathing
•receives influences from external sources

122

pons

pontine respiratory group (PRG
•modifies rhythm of the VRG by outputs to both the VRG and DRG
•adapts breathing to special circumstances such as sleep, exercise, vocalization, and emotional responses

123

hyperventilation

anxiety triggered state in which breathing is so rapid that it expels CO2 from the body faster than it is produced. As blood CO2levels drop, the pH rises causing the cerebral arteries to constrict reducing cerebral perfusion which may cause dizziness or fainting

124

central chemoreceptors

brainstem neurons that respond to changes in pH of cerebrospinal fluid
–pH of cerebrospinal fluid reflects the CO2level in the blood
–by regulating respiration to maintain stable pH, respiratory center also ensures stable CO2level in the blood

125

peripheral chemoreceptors

located in the carotid and aortic bodies of the large arteries above the heart
–respond to the O2and CO2content and the pH of blood

126

stretch receptors

found in the smooth muscles of bronchi and bronchioles, and in the visceral pleura
–respond to inflation of the lungs

127

inflation (Hering-Breuer) reflex

triggered by excessive inflation
•protective reflex that inhibits inspiratory neurons stopping inspiration

128

irritant receptors

nerve endings amid the epithelial cells of the airway
–respond to smoke, dust, pollen, chemical fumes, cold air, and excess mucus
–trigger protective reflexes such as bronchoconstriction, shallower breathing, breath-holding (apnea), or coughing

129

voluntary control over breathing originates in

the motor cortex of frontal lobe of cerebrum
–sends impulses down corticospinal tracts to respiratory neurons in spinal cord, bypassing brainstem

130

breaking point

when CO2levels rise to a point when automatic controls override one’s will

131

respiratory airflow is governed by

the same principles of flow, pressure, and resistance as blood flow
–the flow of a fluid is directly proportional to the pressure difference between two points
–the flow of a fluid is inversely proportional to the resistance

132

atmospheric pressure

drives respiration
–the weight of the air above us
–760 mm Hg at sea level -1 atmosphere (atm)
•lower at higher elevations

133

Boyle’s Law

at a constant temperature, the pressure of a given quantity of gas is inversely proportional to its volume

134

Inspiration

the two pleural layers, their cohesive attraction to each other, and their connections to the lungs and their lining of the rib cage bring about inspiration

135

intrapleural pressure

the slight vacuum that exists between the two pleural layers
–about -4 mm Hg

136

intrapulmonary pressure

the pressure in the alveoli drops -3 mm Hg

137

Charles’s Law

the given quantity of a gas is directly proportional to its absolute temperature

138

in quiet breathing, the dimensions of the thoracic cage increase

only a few millimeters in each direction
–enough to increase its total volume by 500 mL.
–thus, 500 mL of air flows into the respiratory tract

139

relaxed breathing

–passive process achieved mainly by the elastic recoil of the thoracic cage
–recoil compresses the lungs
–volume of thoracic cavity decreases
–raises intrapulmonary pressure to about +3 mm Hg
–air flows down the pressure gradient and out of the lungs

140

forced breathing

accessory muscles raise intrapulmonary pressure as high as +30 mmHg
–massive amounts of air moves out of the lungs

141

pneumothorax

presence of air in pleural cavity
–thoracic wall is punctured
–inspiration sucks air through the wound into the pleural cavity
–potential space becomes an air filled cavity
–loss of negative intrapleural pressure allows lungs to recoil and collapse

142

atelectasis

collapse of part or all of a lung
–can also result from an airway obstruction

143

Resistance to Airflow

pressure is one determinant of airflow -resistance is the other
–the greater the resistance the slower the flow

144

three factors influencing airway resistance

diameter of the bronchioles
pulmonary compliance
surface tension of the alveoli and distal bronchioles

145

pulmonary compliance

the ease with which the lungs can expand

146

surface tension of the alveoli and distal bronchioles

surfactant–reduces surface tension of water

147

Alveolar Surface Tension

thin film of water needed for gas exchange
–creates surface tension that acts to collapse alveoli and distal bronchioles

148

pulmonary surfactant

produced by the great alveolar cells
–decreases surface tension by disrupting the hydrogen bonding in water

149

infant respiratory distress syndrome

premature infants that lack surfactant suffer from infant respiratory distress syndrome (IRDS)
–great difficulty in breathing
–treated with artificial surfactant until lungs can produce own

150

Alveolar Ventilation

•only air that enters the alveoli is available for gas exchange
•not all inhaled air gets there
•about 150 mL fills the conducting division of the airway

151

anatomic dead space

–conducting division of airway where there is no gas exchange
–can be altered somewhat by sympathetic and parasympathetic stimulation

152

physiologic (total) dead space

sum of anatomic dead space and any pathological alveolar dead space

153

alveolar ventilation rate (AVR)

–air that ventilates alveoli (350 mL) X respiratory rate (12 bpm) = 4200 mL/min
–of all the measurements, this one is most directly relevant to the body’s ability to get oxygen to the tissues and dispose of carbon dioxide

154

residual volume

1300 mL that cannot be exhaled with max. effort

155

spirometer

device that recaptures expired breath and records such variables such as rate and depth of breathing, speed of expiration, and rate of oxygen consumption

156

respiratory volumes

tidal volume
inspiratory reserve volume
expiratory reserve volume
residual volume

157

tidal volume

volume of air inhaled and exhaled in one cycle during quiet breathing (500 mL)

158

inspiratory reserve volume

air in excess of tidal volume that can be inhaled with maximum effort (3000 mL)

159

expiratory reserve volume

air in excess of tidal volume that can be exhaled with maximum effort (1200 mL)

160

residual volume

air remaining in lungs after maximum expiration (1300 mL)

161

vital capacity

total amount of air that can be inhaled and then exhaled with maximum effort
–VC = ERV + TV + IRV (4700 mL)
•important measure of pulmonary health

161

total lung capacity

maximum amount of air the lungs can contain
–TLC = RV + VC (6000 mL)

162

spirometry

the measurement of pulmonary function
–aid in diagnosis and assessment of restrictive and obstructive lung disorders

163

restrictive disorders

those that reduce pulmonary compliance
–limit the amount to which the lungs can be inflated

164

obstructive disorders

those that interfere with airflow by narrowing or blocking the airway
–make it harder to inhale or exhale a given amount of air
–asthma, chronic bronchitis

165

forced expiratory volume (FEV)

percentage of the vital capacity that can be exhaled in a given time interval
–healthy adult reading is 75 -85% in 1 sec

166

peak flow

–maximum speed of expiration
–blowing into a handheld meter

167

eupnea

relaxed quiet breathing

168

apnea

temporary cessation of breathing

169

dyspnea

labored, gasping breathing; shortness of breath

170

hyperpnea

increased rate and depth of breathing in response to exercise, pain, or other conditions

171

hyperventilation

increased pulmonary ventilation in excess of metabolic demand

172

hypoventilation

reduced pulmonary ventilation

173

Kussmaul respiration

deep, rapid breathing often induced by acidosis

174

orthopnea

dyspnea that occurs when a person is lying down

175

respiratory arrest

permanent cessation of breathing

176

tachypnea

accelerated respiration

177

composition of air

78.6 % nitrogen, 20.9% oxygen, 0.04% carbon dioxide, 0 –4% water vapor depending on temperature and humidity, and minor gases argon, neon, helium, methane and ozone

178

Dalton’s Law

the total atmospheric pressure is the sum of the contributions of the individual gases

179

partial pressure

the separate contribution of each gas in a mixture

180

composition of inspired air and alveolar is different because of three influences:

-air is humidified by contact with mucous membranes
-freshly inspired air mixes with residual air left from the previous respiratory cycle
-alveolar air exchanges O2and CO2with the blood

181

alveolar gas exchange

the back-and-forth traffic of O2 and CO2across the respiratory membrane

182

for oxygen to get into the blood

it must dissolve in this water
–pass through the respiratory membrane separating the air from the bloodstream

183

for carbon dioxide to leave the blood

it must pass the other way
–diffuse out of the water film into the alveolar air

184

gases diffuse down their own concentration gradient until

until the partial pressure of each gas in the air is equal to its partial pressure in water

185

unload CO2 and load O2 involves

erythrocytes

186

pressure gradient of the gases

–PO2= 104 mm Hg in alveolar air versus 40 mm Hg in blood
–PCO2 = 46 mm Hg in blood arriving versus 40 mm Hg in alveolar air

187

hyperbaric oxygen therapy

treatment with oxygen at greater than one atm of pressure

188

at high altitudes the partial pressures of all gases

are lower
•gradient difference is less, and less oxygen diffuses into the blood

189

solubility of the gases

CO2 20 times as soluble as O2
O2 is twice as soluble as N2

190

Factors Affecting Gas Exchange

membrane thickness
membrane surface area
ventilation-perfusion coupling

191

ventilation-perfusion coupling

–the ability to match ventilation and perfusion to each other
–gas exchange requires both good ventilation of alveolus and good perfusion of the capillaries

192

gas transport

the process of carrying gases from the alveoli to the systemic tissues and vice versa

193

oxygen transport

–98.5% bound to hemoglobin
–1.5% dissolved in plasma

194

carbon dioxide transport

–70% as bicarbonate ion
–23% bound to hemoglobin
–7% dissolved in plasma

195

hemoglobin

molecule specialized in oxygen transport
–four protein (globin) portions

196

carbon monoxide

(CO) -competes for the O2binding sites on the hemoglobin molecule
colorless, odorless gas in cigarette smoke, engine exhaust, fumes from furnaces and space heaters

197

carboxyhemoglobin

CO binds to ferrous ion of hemoglobin

198

carbon dioxide transported in three forms

carbonic acid, carbamino compounds, and dissolved in plasma

199

90% of CO2is

is hydrated to form carbonic acid
–CO2+ H2O → H2CO3→ HCO3-+ H+
–then dissociates into bicarbonate and hydrogen ions

200

systemic gas exchange

the unloading of O2and loading of CO2at the systemic capillaries

201

venous reserve

oxygen remaining in the blood after it passes through the capillary beds

202

four factors that adjust the rate of oxygen unloading

ambient PO2
temperature
Bohr effect
bisphosphoglycerate (BPG)

203

rate and depth of breathing adjust to maintain levels of:

–pH 7.35 –7.45
–PCO240 mm Hg
–PO295 mm Hg

204

brainstem respiratory centers

receive input from central and peripheral chemoreceptors that monitor the composition of blood and CSF

205

most potent stimulus for breathing

pH, followed by CO2, and least significant is O2

206

central chemoreceptors

in the medulla oblongata produce about 75% of the change in respiration induced by pH shift

207

peripheral chemoreceptors

produce about 25% of the respiratory response to pH change

208

acidosis

blood pH lower than 7.35

209

alkalosis

blood pH higher than 7.45

210

hypocapnia

PCO2 less than 37 mm Hg (normal 37 –43 mm Hg)
•most common cause of alkalosis

211

hypercapnia

PCO2 greater than 43 mm Hg
•most common cause of acidosis

212

hyperventilation

is a corrective homeostatic response to acidosis

213

hypoventilation

is a corrective homeostatic response to alkalosis

214

ketoacidosis

acidosis brought about by rapid fat oxidation releasing acidic ketone bodies (diabetes mellitus)

215

Kussmaul respiration

hyperventilation cannot remove ketone bodies, but blowing off CO2, it reduces the CO2concentration and compensates for the ketone bodies to some degree

216

hypoxic drive

respiration driven more by low PO2than by CO2or pH
–emphysema, pneumonia
–high elevations after several days

217

hypoxia

a deficiency of oxygen in a tissue or the inability to use oxygen
–a consequence of respiratory diseases

218

hypoxemic hypoxia

state of low arterial PO2

219

ischemic hypoxia

inadequate circulation of blood

220

anemic hypoxia

due to anemia resulting from the inability of the blood to carry adequate oxygen

221

histotoxic hypoxia

metabolic poisons such as cyanide prevent the tissues from using oxygen delivered to them

222

cyanosis–

blueness of the skin
–sign of hypoxia

223

oxygen toxicity

pure O2 breathed at 2.5 atm or greater

224

Chronic Obstructive Pulmonary Disease

COPD–refers to any disorder in which there is a long-term obstruction of airflow and a substantial reduction in pulmonary ventilation

225

major COPDs are

chronic bronchitis and emphysema

226

chronic bronchitis

inflammation and hyperplasia of the bronchial mucosa

227

sputum

mucus and cellular debris

228

emphysema

alveolar walls break down
lungs fibrotic and less elastic
air passages collapse
weaken thoracic muscles

229

Effects of COPD

reduces pulmonary compliance and vital capacity
•hypoxemia, hypercapnia, respiratory acidosis

230

cor pulmonale

hypertrophy and potential failure of right heart due to obstruction of pulmonary circulation

231

lung cancer

accounts for more deaths than any other form of cancer
–most important cause is smoking (15 carcinogens)

232

squamous-cell carcinoma

(most common)
–begins with transformation of bronchial epithelium into stratified squamous from ciliated pseudostratified epithelium

233

adenocarcinoma

–originates in mucous glands of lamina propria

234

small-cell (oat cell) carcinoma

–least common, most dangerous