A&p 22

Front 1

Respiratory Zone

Back 1

Site of gas exchange; Includes respiratory bronchioles, alveolar ducts, and alveoli (300 million alveoli account for most of lungs volume and are main site for gas exchange)

Front 2

Conducting Zone

Back 2

Conduits in gas exchange sites; Includes all other respiratory sturctures

Front 3

Respiratory Muscles

Back 3

Diaphragm and other muscles that promote ventilation

Front 4

Nose

Back 4

Provides airway; Moistens and warms entering air; Filters inspired air; Serves as a resonating chamber for speech; Houses olfactory receptors; External nose and nasal cavity regions

Front 5

Philtrum (Nose)

Back 5

Shallow vertical groove inferior to apex

Front 6

Nostrils (Nares)

Back 6

Bounded laterally by alae

Front 7

Nasal Cavity

Back 7

In and posterior to external nose; Divided by midline nasal septum; Posterior nasal apertures (choanae) open into nasal pharynx; Roof is ethmoid and sphenoid bones; Floor is hard and soft palates

Front 8

Respiratory Mucosa

Back 8

In nasal cavity; Pseudostratified ciliated columnar epithelium; Mucous and serous secretions contain lysozyme and defensins; Cilia move contaminated mucus to throat; Inspired air warmed by plexuses of capillaries/veins; Sensory nerve endings trigger sneezing

Front 9

Nasal Conchae

Back 9

Superior, middle, and inferior ones; Protrude from lateral walls in nasal cavity; Increase mucosal area; Enhance air turbulence

Front 10

Functions of Nasal Mucosa and Conchae

Back 10

During inhalation they filter, heat, and moisten air; During exhalation they reclaim heat and moisture

Front 11

Paranasal Sinuses

Back 11

In frontal, sphenoid, ethmoid, and maxillary bones; Lighten the skull and help to warm and moisten air

Front 12

Pharynx

Back 12

Muscular tube that connects to nasal cavity and mouth superiorly, larynx and esophagus inferiorly; From base of skull to level of sixth cervical vertebra

Front 13

Larynx

Back 13

Attaches to hyoid bone and opens into laryngopharynx; Continuous with trachea; Functions - provides patent airway, routes air and food into proper channels, voice production

Front 14

Larynx Cartilages

Back 14

Hyaline cartilage except for epiglottis; Thyroid cartilage with laryngeal prominence (Adam's apple); Ring shaped cricoid cartilage; Paired arytenoid, cuneiform, and comiculate cartilages

Front 15

Epiglottis

Back 15

Elastic cartilage - covers laryngeal inlet during swallowing

Front 16

Vocal Ligaments

Back 16

Attach the arytenoid cartilages to thyroid cartilage; Contain elastic fibers; Form core of vocal folds - opening between them is glottis, folds vibrate to produce sound as air rushes up from the lungs

Front 17

Trachea

Back 17

Windpipe - from larynx to mediastnum; Wall composed of three layers - mucosa, submucosa, and adventitia

Front 18

Mucosa

Back 18

Wall layer of trachea; Ciliated pseudostratified epithelium with goblet cells

Front 19

Submucosa

Back 19

Wall layer of trachea; Connective tissue with seromucous glands

Front 20

Adventitia

Back 20

Outermost wall layer of trachea; connective tissue that encases the C shaped rings of hyaline cartilage

Front 21

Trachealis Muscle

Back 21

Connects posterior parts of cartilage rings; Contracts during coughing to expel mucus

Front 22

Carina

Back 22

Last tracheal cartilage; Point where trachea branches into two bronchi

Front 23

Bronchi and Subdivisions

Back 23

AIr passages undergo 23 orders of branching; Branching patter called bronchial tree

Front 24

Conducting Zone Structures

Back 24

Trachea to right and left primary bronchi; Each main bronchus enters the hilum of one lung - right main bronchus is wider, shorter, more vertical than left; Each primary bronchus branches into secondary bronchi, each secondary bronchus supplies one lobe and branches into tertiary bronchi (segmental bronchi divide repeatedly; Bronchioles less than 1 mm in diameter; Terminal bronchioles are smallest, less than .5 mm in diameter

Front 25

Structural Changes of Bronchi though Bronchioles

Back 25

Cartilage rings give way to plates, cartilage is absent from bronchioles; Epithelium changes from pseudostratified columnar to cuboidal epithelium - cilia and goblet cells become sparse; Relative amount of smooth muscle increases

Front 26

Respiratory Membrane

Back 26

. um thick air blood barrier; Alveolar and capillary walls and their fused basement membranes; Scattered type II cuboidal cells secrete surfactant and antimicrobial proteins

Front 27

Alveolar Walls

Back 27

Single layer of squamous epithelium

Front 28

Alveoli

Back 28

Surrounded by fine elastic fibers; Contain open pores - connect adjacent alveoli, allow air pressure throughout lung to be equalized; House alveolar macrophages that keep alveolar surfaces sterile

Front 29

Lungs

Back 29

Left lung is smaller, separated into two lobes by oblique fissure; Right lung has three lobes separated by oblique and horizontal fissures; Bronchopulmonary segments (10 right, 8-9 left); Lobules are smallest subdivisions, served by bronchioles and their branches

Front 30

Blood Supply

Back 30

Pulmonary circulation (low pressure, high volume); Pulmonary arteries deliver systemic venous blood - branch profusely, along with bronchi and feed into the pulmonary capillary networks; Pulmonary veins carry oxygenated blood from respiratory zones to heart

Front 31

Pleurae

Back 31

Thin, double layered serosa; Parietal pleura on thoracic wall and superior face of diaphragm; Visceral pleura on external lung surface; Pleural fluid fills the slitlike pleural cavity - provides lubrication and surface tension

Front 32

Inspiration

Back 32

Gases flow into lungs; Active process; Inspiratory muscles contract; Thoracic vol. increases; Lungs stretch, intrapulmonary vol. increases; P pul pressure drops (to -1 mm Hg); Air flows into lungs down its pressure gradient until P pul = P atm

Front 33

Expiration

Back 33

Gases exit lungs; Quiet expiration normally passive process; Inspiratory muscles relax; Thoracic cavity vol. decreases; Elastic lungs recoil and P pul decreases; P pul rises to +1 mm Hg; Air flows out of lungs down it pressure gradient until P pul = 0

Front 34

Atmospheric Pressure (P atm)

Back 34

Pressure exerted by air surrounding the body; 760 mm Hg at sea level

Front 35

Respiratory Pressures

Back 35

Described relative to P atm; Negative respiratory pressure is less than P atm, positive is greater than P atm; 0 respiratory pressure = P atm

Front 36

Intrapulmonary Pressure (P pul)

Back 36

Intra-alveolar; Pressure in the alveoli; Fluctuates with breathing; Always eventually equalizes with P atm

Front 37

Intrapleural Pressure (P ip)

Back 37

Pressure in pleural cavity; Fluctuates with breathing; Always negative pressure (less than P atm and P pul); Negative P ip caused by opposing forces, two inward forces promote lung collapse - elastic recoil of lungs decreases lung size and surface tension of alveolar fluid reduces alveolar size; One outward force enlarges lungs - elasticity of chest wall pulls thorax outward

Front 38

Pressure Relationships

Back 38

If P ip = P pul, lungs collapse

Front 39

Transpulmonary Pressure

Back 39

P pul - P ip; Keeps the airways open; The greater the transpulmonary pressure, the larger th lungs

Front 40

Atelectasis

Back 40

Lung collapse; Caused by plugged bronchioles (collapse of alveoli) or a wound that admits air into pleural cavity (pneumothorax)

Front 41

Pulmonary Ventilaation

Back 41

Inspiration and expiration; Mechanical processes that depend on volume changes in thoracic cavity; Volume changes lead to pressure changes, pressure changes lead to gas flow that equalizes pressure

Front 42

Forced Expiration

Back 42

Active process, uses abdominal and internal intercostal muscles

Front 43

Physical Factors of Pulmonary Ventilation

Back 43

Airway resistance; Alveolar surface tension; Lung compliance

Front 44

Airway Resistance

Back 44

F = ^P/R; ^P is pressure gradient between atmosphere and alveoli (2 mm Hg or less during normal breathing); Gas flow changes inversely with R; Insignificant (large airway diameters, progressive branching of airways); R disappears at terminal bronchioles where diffusion drives gas movement; As R increases, breathing movements become more strenuous

Front 45

Constriction/Obstruction of Bronchioles

Back 45

Can prevent life sustaining ventilation; Can occur during acute asthma attacks and stop ventilation

Front 46

Friction

Back 46

Major nonelastic source of resistance

Front 47

Epinephrine

Back 47

Dilates bronchioles and reduces air resistance

Front 48

Alveolar Surface Tension

Back 48

Attracts liquid molecules to one another at a gas liquid interface; Resists any force that tends to increase surface area of liquid

Front 49

Surfactant

Back 49

Detergent like lipid and protein complex produced by type II alveolar cells; Reduces surface tension of alveolar collapse; Insufficient quantity in premature infants causes infant respiratory distress syndrome

Front 50

Lung Compliance

Back 50

Measure of change in lung volume that occurs with a given change in transpulmonary pressure; Normally high due to distensibility of lung tissue and alveolar surface tension; Diminished by nonelastic scar tissue (fibrosis), reduced production of surfactant, and decreased flexibility of thoracic cage

Front 51

Imbalances that Reduce Lung Compliance

Back 51

Deformities of thorax; Ossification of costal cartilage; Paralysis of intercostal muscles

Front 52

Respiratory Volumes

Back 52

Used to assess a person's respiratory status

Front 53

Tidal Volume (TV

Back 53

Amount of air inhaled or exhaled with each breath under resting conditions

Front 54

Inspiratory Reserve Volume (IRV)

Back 54

Amount of air that can be forcefully inhaled after a normal tidal volume inhalation

Front 55

Expiratory Reserve Volume

Back 55

Amount of air that can be forcefully exhaled after a normal tidal volume exhalation

Front 56

Residual Volume

Back 56

Amount of air remaining in the lungs after a forced exhalation

Front 57

Total Lung Capacity (TLC)

Back 57

Max amount of air contained in lungs after a max inspiratory action; TLC = TV + IRV + ERV + RV

Front 58

Vital Capacity (VC)

Back 58

Max amount of air that can be expired after a max inspiratory effort; VC = TV + IRV + ERV

Front 59

Inspiratory Capacity (IC)

Back 59

Max amount of air that can be inspired after a normal expiration; IC = TV + IRV

Front 60

Functional Residual Capacity (FRC)

Back 60

Volume of air remaining in lungs after a normal tidal volume expiration; FRC = ERV + RV

Front 61

Spirometer

Back 61

Instrument used to measure respiratory volumes and capacities; Can distinguish between Obstructive Pulmonary DIsease and Restrictive Disorders

Front 62

Obstructive Pulmonary Disease

Back 62

Increased airway resistance (ex: bronchitis)

Front 63

Restrictive Disorders

Back 63

Reduction in total lung capacity due to structural or functional lung changes (fibrosis or TB)

Front 64

Partial Pressure Gradient (O2 in Lungs)

Back 64

Venous blood Po2 = 40 mm Hg; Alveolar Po2 = 104 mm Hg (O2 partial pressures reach equilibrium of 104 mm Hg in .25 seconds)

Front 65

Partial Pressure Gradient (CO2 in Lungs)

Back 65

Pco2 in lungs less steep than O2; Venous blood Pco2 = 45 mm Hg; Alveloar Pco2 = 40 mm Hg; CO2 is 20 times more soluble in plasma than oxygen; Co2 diffuses in equal amount with oxygen

Front 66

Respiratory Membranes

Back 66

.5 to 1 um thick; Large total surface area (40 times that of one's skin); Thicken if lungs become waterlogged and edematous and gas exchange become inadequate; Reduction in surface area with emphysema, when walls of adjacent alveoli break down

Front 67

Internal Respiration

Back 67

Capillary gas exchange in body tissues; Partial pressures and diffusion gradients are reversed compared to external respiration; Po2 in tissue is always lower than in systemic arterial blood

Front 68

Oxygen Transport

Back 68

Molecular O2 is carried in blood - 1.5% dissolved in plasma, 98.5% loosely bound to each Fe of Hb in RBCs, 4 O2 per Hb

Front 69

Oxyhemoglobin (HbO2)

Back 69

Hemoglobin - Oxygen combination

Front 70

Reduced Hemoglobin (HHb)

Back 70

Hemoglobin that has released O2

Front 71

O2 Loading/Unloading

Back 71

Facilitated by change in shape of Hb - as O2 binds, Hb affinity for O2 increases, as O2 is released, Hb affinity for O2 decreases; Fully saturated if all four heme groups carry O2; Partially saturate when one to three hemes carry O2; Only 20 - 25% of bound O2 is unloaded during 1 systemic circulation

Front 72

Po2 Influence on Hb Saturation

Back 72

In arterial blood, Po2 = 100 mm Hg; Contains 20 ml oxygen per 100 ml blood (20 vol %); Hb is 99% saturated; Further increases in Po2 produce minimal increases in O2 binding

Front 73

Drop of O2 Levels in Tissues

Back 73

More oxygen dissociates from Hb and is used by cells; Respiratory rate of cardiac output need not increase

Front 74

Other Factors Influencing Hb Saturation

Back 74

Increases in temp., H+, Pco2, and BPG - modify structure of Hb and decrease affinity for O2, occur in systemic capillaries, enhance O2 unloading, shift O2 Hb dissociation curve to right; Decreases in these factors shift curve to left

Front 75

Factors that Increased Hb O2 Release

Back 75

As cells metabolize glucose - Pco2 and H= increase in concentration in capillary blood; Heat production increases - increasing temp. decreases Hb affinity for O2

Front 76

Bohr Effect

Back 76

Declining pH weakens Hb O2 bond

Front 77

CO2 Transport

Back 77

CO2 transported in blodo in three forms - 7 to 10 % dissolved in plasma, 20% bound to globin of Hb (carbaminohemoglobin), 70% transported as bicarbonate ions (HCO3) in plasma

Front 78

Respiration Control

Back 78

Involves neurons in reticular formation of medulla and pons

Front 79

Dorsal Respiratory Group (DRG)

Back 79

Near root of cranial nerve IX; Integrates input from peripheral stretch and chemoreceptors

Front 80

Ventral Respiratory Group (VRG)

Back 80

Rhythm generating and integrative center; Sets eupnea (12-15 breaths/minute); Inspiratory neurons excite inspiratory muscles and intercostal nerves - autorhythmically seen in pre-Botzinger neurons; Expiratory neurons inhibit the inspiratory neurons

Front 81

Pontine Respiratory Centers

Back 81

Influence and modify activity of VRG; Smooth out transition between inspiration between inspiration and expiration and vice versa

Front 82

Genesis of Respiratory Rhythm

Back 82

Not well understood; Most widely accepted hypothesis is reciprocal inhibition of two sets of interconnected neuronal networks in medulla sets rhythm.

Front 83

Depth of Breathing

Back 83

Determined by how actively the respiratory center stimulates respiratory muscles

Front 84

Rate of Breathing

Back 84

Determined by how long the inspiratory center is active

Front 85

Influence of Pco2

Back 85

If Pco2 level rise (hpyercapnia, CO2 accumulates in brain; CO2 is hydrated - resulting carbonic acid dissociates releasing H+; H+ stimulates central chemoreceptors of brain stem; Chemoreceptors synapse with respiratory regulatory centers, increasing depth and rate of breathing

Front 86

Hyperventiliation

Back 86

Increased depth and rate of breathing that exceeds body's need to remove CO2; Cause CO2 levels to decline (hypocapnia); May cause cerebral vasoconstriction and cerebral ischemia

Front 87

Apnea

Back 87

Period of breathing cessation that occurs when Pco2 is abnormally low

Front 88

Influence of Po2

Back 88

Peripheral chemoreceptors in aortic and carotid bodies are O2 sensors - when excited, they cause increased ventilation; Substantial drops in aterial Po2 must occur in order to stimulate increased ventilation

Front 89

Influence of Arterial pH

Back 89

Can modify respiratory rat and rhythm even if CO2 and O2 levels are normal; Decreased pH may reflect CO2 retention, accumulation of lactic acid, excess ketone bodies in patients with diabetes melitus; Respiratory system controls will attempt to raise pH by increasing respiratory rate and depth

Front 90

Chemical Factors Summary

Back 90

Rising CO2 levels are most powerful respiratory stimulant; Normally blood Po2 affects breathing only indirectly by influencing peripheral chemoreceptor sensitivity to changes in Pco2; When arterial Po2 falls below below 60 mm Hg, it become major stimulus for respiration (via peripheral chemoreceptors); Changes in arterial pH resulting from CO2 retention or metabolic factors act indirectly though the peripheral chemoreceptors

Front 91

Hypothalamic Controls

Back 91

Act through limbic system to modify rate and depth of respiration

Front 92

Rise in Body Temp.

Back 92

Acts to increase respiratory rate

Front 93

Cortical Controls

Back 93

Direct signals from the cerebral motor cortex that bypass medullary controls (like voluntary breath holding)

Front 94

Chronic Obstructive Pulmonary Disease (COPD)

Back 94

Exemplified by chronic bronchitis and emphysema; Irreversible decrease in ability to force air out of lungs

Front 95

Athsma

Back 95

Characterized by coughing, dyspnea, wheezing, chest tightness; Active inflammation of airways precedes bronchospasms; Inflammation is immune response caused by releases of interleukin, lgE production, and recruitment of inflammatory cells; Airways thickened with inflammatory exudate magnify effect of bronchospasms

Front 96

Tuberculosis

Back 96

Infectious disease; Symptoms include fever, night sweats, weight loss, racking cough, spitting up blood; Treatment entails 12 month course of antibiotics

Front 97

Mycobacterium tuberculosis

Back 97

Bacterium that causes Tuberculosis