Urinary System

Question 1

Introduction

• Breathing represents life!
– first breath of newborn baby to last at death

• All body processes directly or indirectly require ATP
– ATP synthesis requires O2 & produces CO2
– drives our need to breathe

Answer 1

Introduction

• Breathing represents life!
– first breath of newborn baby to last at death

• All body processes directly or indirectly require ATP
– ATP synthesis requires O2 & produces CO2
– drives our need to breathe

Question 2

Respiratory System

• System of tubes that delivers air to lungs

• Respiratory & cardiovascular systems collaborate to deliver O2 to tissues & remove CO2
– “cardiopulmonary system” – disorders of one affects other

• Respiratory system & urinary system collaborate to regulate acid–base balance

Answer 2

Respiratory System

• System of tubes that delivers air to lungs

• Respiratory & cardiovascular systems collaborate to deliver O2 to tissues & remove CO2
– “cardiopulmonary system” – disorders of one affects other

• Respiratory system & urinary system collaborate to regulate acid–base balance

Question 3

Respiratory System: Functions
– provides O2 & CO2 exchange

– serves for speech / vocalizations

– provides for sense of smell

– affects pH of body fluids

– affects blood pressure (convert angiotensin)

– creates respiratory pump - promotes flow of lymph & venous blood

– breath-holding helps expel abdominal contents during urination, defecation, childbirth (Valsalva maneuver)

Answer 3

Respiratory System: Functions
– provides O2 & CO2 exchange

– serves for speech / vocalizations

– provides for sense of smell

– affects pH of body fluids

– affects blood pressure (convert angiotensin)

– creates respiratory pump - promotes flow of lymph & venous blood

– breath-holding helps expel abdominal contents during urination, defecation, childbirth (Valsalva maneuver)

Question 4

Respiratory System: Anatomy

• Nose, pharynx, larynx, trachea, bronchi, lungs
– bronchial tree to alveoli
• millions of thin-walled air sacs

• exchanges gases w/ blood through alveolar wall

• Conducting division
– passages serve only for airflow
– no gas exchange
– nostrils –> –> major bronchioles

• Respiratory division
– alveoli & other gas exchange regions
• Upper respiratory tract—head & neck
– nose –> larynx

• Lower respiratory tract—thorax
– trachea –> lungs

Answer 4

Respiratory System: Anatomy

• Nose, pharynx, larynx, trachea, bronchi, lungs
– bronchial tree to alveoli
• millions of thin-walled air sacs

• exchanges gases w/ blood through alveolar wall

• Conducting division
– passages serve only for airflow
– no gas exchange
– nostrils –> –> major bronchioles

• Respiratory division
– alveoli & other gas exchange regions
• Upper respiratory tract—head & neck
– nose –> larynx

• Lower respiratory tract—thorax
– trachea –> lungs

Question 5

Identify

Answer 5

Identify

Question 6

Nose

• Functions
– filters, warms, humidifies inhaled air
– detects odors
– is resonating chamber - amplifies voice

• Nose = nostrils (nares) to posterior nasal apertures

Answer 6

Nose

• Functions
– filters, warms, humidifies inhaled air
– detects odors
– is resonating chamber - amplifies voice

• Nose = nostrils (nares) to posterior nasal apertures

Question 7

Nose
• Three folds of tissue— nasal conchae

– superior, middle, and inferior nasal conchae (turbinates)

• project from lateral walls toward septum
• meatus—narrow air passage beneath conchae
• ensures that air contacts mucous membranes – filters, warms, moistens

Answer 7

Nose
• Three folds of tissue— nasal conchae

– superior, middle, and inferior nasal conchae (turbinates)

• project from lateral walls toward septum
• meatus—narrow air passage beneath conchae
• ensures that air contacts mucous membranes – filters, warms, moistens

Question 8

Nose

• Olfactory epithelium—detects odors
– ciliated pseudostratified columnar epithelium
– immobile cilia bind odorant molecules

Respiratory epithelium
– ciliated pseudostratified columnar epithelium w/ goblet cells
– cilia = motile
– goblet cells secrete mucus; cilia propel mucus toward pharynx
– swallowed

Answer 8

Nose

• Olfactory epithelium—detects odors
– ciliated pseudostratified columnar epithelium
– immobile cilia bind odorant molecules

Respiratory epithelium
– ciliated pseudostratified columnar epithelium w/ goblet cells
– cilia = motile
– goblet cells secrete mucus; cilia propel mucus toward pharynx
– swallowed

Question 9

Respiratory Epithelium

Answer 9

Respiratory Epithelium

Question 10

Upper Respiratory Tract: Anatomy

Answer 10

Upper Respiratory Tract: Anatomy

Question 11

Pharynx

• Pharynx (throat)—from posterior nasal apertures to larynx

• 3 regions
– Nasopharynx
• posterior to nasal apertures, above soft palate
• receives auditory tubes & contains pharyngeal tonsil

– Oropharynx
• space betw/ soft palate & epiglottis
• contains palatine tonsils

– Laryngopharynx
• epiglottis to cricoid cartilage
• esophagus begins at that point

Answer 11

Pharynx

• Pharynx (throat)—from posterior nasal apertures to larynx

• 3 regions
– Nasopharynx
• posterior to nasal apertures, above soft palate
• receives auditory tubes & contains pharyngeal tonsil

– Oropharynx
• space betw/ soft palate & epiglottis
• contains palatine tonsils

– Laryngopharynx
• epiglottis to cricoid cartilage
• esophagus begins at that point

Question 12

Upper Respiratory Tract: Anatomy

Answer 12

Upper Respiratory Tract: Anatomy

Question 13

Pharynx

• Nasopharynx passes only air
– pseudostratified columnar epithelium

• Oropharynx & laryngopharynx pass air, food, & drink
– stratified squamous epithelium

Answer 13

Pharynx

• Nasopharynx passes only air
– pseudostratified columnar epithelium

• Oropharynx & laryngopharynx pass air, food, & drink
– stratified squamous epithelium

Question 14

Larynx
• Larynx (voice box)—cartilaginous chamber

• Primary function - keep food / drink out of airway
– additional role: phonation— production of sound!

Answer 14

Larynx
• Larynx (voice box)—cartilaginous chamber

• Primary function - keep food / drink out of airway
– additional role: phonation— production of sound!

Question 15

Larynx
• Epiglottis—flap of tissue - guards superior opening of larynx

– at rest, almost vertical

– during swallowing, larynx moves upward

– tongue pushes epiglottis down to meet it

– closes airway & directs food to esophagus

– vestibular folds of larynx play greater role in keeping food & drink out of airway

Answer 15

Larynx
• Epiglottis—flap of tissue - guards superior opening of larynx

– at rest, almost vertical

– during swallowing, larynx moves upward

– tongue pushes epiglottis down to meet it

– closes airway & directs food to esophagus

– vestibular folds of larynx play greater role in keeping food & drink out of airway

Question 16

Identify

Answer 16

Identify

Question 17

Larynx
• Nine cartilages make up framework of larynx

• First 3 solitary & relatively large
– Epiglottic cartilage: spoon-shaped supportive plate in epiglottis; most superior one

– Thyroid cartilage: largest, laryngeal prominence, shield- shaped
• testosterone in males –> Adam’s apple

– Cricoid cartilage: connects larynx to trachea, ring-shaped

Answer 17

Larynx
• Nine cartilages make up framework of larynx

• First 3 solitary & relatively large
– Epiglottic cartilage: spoon-shaped supportive plate in epiglottis; most superior one

– Thyroid cartilage: largest, laryngeal prominence, shield- shaped
• testosterone in males –> Adam’s apple

– Cricoid cartilage: connects larynx to trachea, ring-shaped

Question 18

Identify

Answer 18

Identify

Question 19

Larynx

• Interior wall: two folds on each side betw/ thyroid & arytenoid cartilages

– Superior vestibular folds
• no role in speech

• close larynx during swallowing

– Inferior vocal cords
• produce sound when air passes betw/ them

• contain vocal ligaments
• covered w/ stratified squamous epithelium
• glottis—vocal cords & opening betw/ them

Answer 19

Larynx

• Interior wall: two folds on each side betw/ thyroid & arytenoid cartilages

– Superior vestibular folds
• no role in speech

• close larynx during swallowing

– Inferior vocal cords
• produce sound when air passes betw/ them

• contain vocal ligaments
• covered w/ stratified squamous epithelium
• glottis—vocal cords & opening betw/ them

Question 20

Larynx - folds

Answer 20

Larynx - folds

Question 21

Respiratory Tract: Endoscopic view

Answer 21

Respiratory Tract: Endoscopic view

Question 22

Larynx
Adult male vocal cords
• usually longer & thicker
• vibrate slower, lower-pitched sound

– Loudness: determined by force of air passing betw/ vocal cords

– vocal cords produce crude sounds; words formed by pharynx, oral cavity, tongue & lips

Answer 22

Larynx
Adult male vocal cords
• usually longer & thicker
• vibrate slower, lower-pitched sound

– Loudness: determined by force of air passing betw/ vocal cords

– vocal cords produce crude sounds; words formed by pharynx, oral cavity, tongue & lips

Question 23

Trachea
• Trachea—rigid tube about 4.5 in. long & 1 in. in diameter

– anterior to esophagus

– supported by C-shaped rings of hyaline cartilage

– reinforces trachea; keeps it from collapsing during inhalation

Answer 23

Trachea
• Trachea—rigid tube about 4.5 in. long & 1 in. in diameter

– anterior to esophagus

– supported by C-shaped rings of hyaline cartilage

– reinforces trachea; keeps it from collapsing during inhalation

Question 24

Trachea
• Inner lining - ciliated pseudostratified columnar epithelium

– mucus-secreting cells, ciliated cells, & stem cells

– mucociliary escalator: mechanism for debris removal
• mucus traps inhaled particles
• upward beating cilia drive mucus toward pharynx

Answer 24

Trachea
• Inner lining - ciliated pseudostratified columnar epithelium

– mucus-secreting cells, ciliated cells, & stem cells

– mucociliary escalator: mechanism for debris removal
• mucus traps inhaled particles
• upward beating cilia drive mucus toward pharynx

Question 25

_Tracheostomy_ • Tracheostomy—temporary opening in trachea inferior to larynx; tube inserted to allow airflow – prevents asphyxiation due to upper airway obstruction – inhaled air bypasses nasal cavity, so not humidified – if left too long, mucous membranes dry out, promoting infection

Answer 25

_Tracheostomy_ • Tracheostomy—temporary opening in trachea inferior to larynx; tube inserted to allow airflow – prevents asphyxiation due to upper airway obstruction – inhaled air bypasses nasal cavity, so not humidified – if left too long, mucous membranes dry out, promoting infection

Question 26

_Cricothyroidotomy_

Answer 26

_Cricothyroidotomy_

Question 27

Lower Respiratory Tract: Anatomy

Answer 27

Lower Respiratory Tract: Anatomy

Question 28

_Bronchial Tree_ • Bronchial tree—branching air tubes in each lung – from main bronchus to 65,000 terminal bronchioles! * Main (primary) bronchi—supported by C-shaped hyaline cartilage rings * Lobar (secondary) bronchi—supported by crescent-shaped cartilage plates * Segmental (tertiary) bronchi—same (plates) * all lined w/ ciliated pseudostratified columnar epithelium

Answer 28

_Bronchial Tree_ • Bronchial tree—branching air tubes in each lung – from main bronchus to 65,000 terminal bronchioles! * Main (primary) bronchi—supported by C-shaped hyaline cartilage rings * Lobar (secondary) bronchi—supported by crescent-shaped cartilage plates * Segmental (tertiary) bronchi—same (plates) * all lined w/ ciliated pseudostratified columnar epithelium

Question 29

Primary Bronchi

Answer 29

Primary Bronchi

Question 30

_Lungs & Bronchial Tree_ • Lung—conical shape – broad, concave base on diaphragm – apex projects slightly above clavicle – costal surface: pressed against ribcage – mediastinal surface: faces medially toward heart • hilum—slit through which lung receives main bronchus, blood vessels, lymphatics, & nerves • root of lung

Answer 30

_Lungs & Bronchial Tree_ • Lung—conical shape – broad, concave base on diaphragm – apex projects slightly above clavicle – costal surface: pressed against ribcage – mediastinal surface: faces medially toward heart • hilum—slit through which lung receives main bronchus, blood vessels, lymphatics, & nerves • root of lung

Question 31

Lungs: Gross Anatomy

Answer 31

Lungs: Gross Anatomy

Question 32

_Lungs & Bronchial Tree_ • Lungs: non-symmetrical – right lung • shorter b/c of liver • three lobes—superior, middle, & inferior— separated by horizontal & oblique fissure – left lung • taller & narrower b/c heart tilts left • indentation—cardiac impression • two lobes—superior & inferior separated by single oblique fissure

Answer 32

_Lungs & Bronchial Tree_ • Lungs: non-symmetrical – right lung • shorter b/c of liver • three lobes—superior, middle, & inferior— separated by horizontal & oblique fissure – left lung • taller & narrower b/c heart tilts left • indentation—cardiac impression • two lobes—superior & inferior separated by single oblique fissure

Question 33

Lungs

Answer 33

Lungs

Question 34

_Bronchial Tree_ • Bronchioles – lack cartilage – \< 1 mm diameter – pulmonary lobule: portion of lung ventilated by one bronchiole – ciliated cuboidal epithelium – well-developed smooth muscle – divides into 50-80 terminal bronchioles

Answer 34

_Bronchial Tree_ • Bronchioles – lack cartilage – \< 1 mm diameter – pulmonary lobule: portion of lung ventilated by one bronchiole – ciliated cuboidal epithelium – well-developed smooth muscle – divides into 50-80 terminal bronchioles

Question 35

_Bronchial Tree_ Respiratory bronchioles – alveoli budding from walls – divide into 2-10 alveolar ducts – end in alveolar sacs: clusters of alveoli arrayed around

Answer 35

_Bronchial Tree_ Respiratory bronchioles – alveoli budding from walls – divide into 2-10 alveolar ducts – end in alveolar sacs: clusters of alveoli arrayed around

Question 36

_Alveoli_ • 150 million alveoli in each lung, providing ~ 70 m2 of surface for gas exchange • cells – Squamous (type I) alveolar cells • thin, broad cells - allow for rapid gas diffusion betw/ alveolus & blood • cover 95% of alveolus surface area

Answer 36

_Alveoli_ • 150 million alveoli in each lung, providing ~ 70 m2 of surface for gas exchange • cells – Squamous (type I) alveolar cells • thin, broad cells - allow for rapid gas diffusion betw/ alveolus & blood • cover 95% of alveolus surface area

Question 37

_Alveoli_ – Great (type II) alveolar cells • round / cuboidal cells - cover other 5% of alveolar surface • repair alveolar epithelium when squamous (type I) cells damaged • secrete pulmonary surfactant – phospholipids & proteins that coat alveoli; prevent collapsing during exhalation

Answer 37

_Alveoli_ – Great (type II) alveolar cells • round / cuboidal cells - cover other 5% of alveolar surface • repair alveolar epithelium when squamous (type I) cells damaged • secrete pulmonary surfactant – phospholipids & proteins that coat alveoli; prevent collapsing during exhalation

Question 38

_Alveoli_ – Alveolar macrophages (dust cells) • most numerous cells in lung! • wander in & betw/ alveoli • phagocytize dust particles • 100 million dust cells perish each day as they ride up mucociliary escalator to be swallowed & digested

Answer 38

_Alveoli_ – Alveolar macrophages (dust cells) • most numerous cells in lung! • wander in & betw/ alveoli • phagocytize dust particles • 100 million dust cells perish each day as they ride up mucociliary escalator to be swallowed & digested

Question 39

Alveoli

Answer 39

Alveoli

Question 40

_Alveoli_ * each alveolus surrounded by basket of capillaries supplied by pulmonary artery * Respiratory membrane—barrier betw/ alveolar air & blood * important to prevent fluid accumulation in alveoli

Answer 40

_Alveoli_ * each alveolus surrounded by basket of capillaries supplied by pulmonary artery * Respiratory membrane—barrier betw/ alveolar air & blood * important to prevent fluid accumulation in alveoli

Question 41

Respiratory System

Answer 41

Respiratory System

Question 42

_Pleurae_ • Visceral pleura—serous membrane, covers lungs • Parietal pleura—adheres to mediastinum, inner surface of rib cage, & superior surface of diaphragm • Pleural cavity—potential space betw/ pleurae – film of slippery pleural fluid • Functions: – reduce friction – create pressure gradient • assists lung inflation – compartmentalize • prevents spread of infection

Answer 42

_Pleurae_ • Visceral pleura—serous membrane, covers lungs • Parietal pleura—adheres to mediastinum, inner surface of rib cage, & superior surface of diaphragm • Pleural cavity—potential space betw/ pleurae – film of slippery pleural fluid • Functions: – reduce friction – create pressure gradient • assists lung inflation – compartmentalize • prevents spread of infection

Question 43

_Breathing_ • Breathing (pulmonary ventilation)—repetitive cycle of inspiration & expiration • Respiratory cycle = one complete inspiration & expiration – quiet respiration: effortless & automatic – forced respiration: deep, rapid breathing, e.g. exercise * Air flow depends on pressure difference - outside air vs. air inside lungs * Breathing muscles change lung volumes, create pressure differences relative to atmosphere

Answer 43

_Breathing_ • Breathing (pulmonary ventilation)—repetitive cycle of inspiration & expiration • Respiratory cycle = one complete inspiration & expiration – quiet respiration: effortless & automatic – forced respiration: deep, rapid breathing, e.g. exercise * Air flow depends on pressure difference - outside air vs. air inside lungs * Breathing muscles change lung volumes, create pressure differences relative to atmosphere

Question 44

_Respiratory Muscles_ • Diaphragm – Prime mover of respiration – contraction: diaphragm descends, thoracic cavity enlarges, air enters – relaxation: diaphragm bulges upward, lungs compressed, air expelled – accounts for 2/3 of airflow

Answer 44

_Respiratory Muscles_ • Diaphragm – Prime mover of respiration – contraction: diaphragm descends, thoracic cavity enlarges, air enters – relaxation: diaphragm bulges upward, lungs compressed, air expelled – accounts for 2/3 of airflow

Question 45

Diaphragm

Answer 45

Diaphragm

Question 46

_Respiratory Muscles_ • External intercostal muscles – synergists to diaphragm – stiffen thoracic cage during respiration – prevent it from caving inward when diaphragm descends – help enlarge thoracic cage – other 1/3 of airflow • Scalenes – synergists to diaphragm – hold ribs 1 & 2 stationary in quiet respiration

Answer 46

_Respiratory Muscles_ • External intercostal muscles – synergists to diaphragm – stiffen thoracic cage during respiration – prevent it from caving inward when diaphragm descends – help enlarge thoracic cage – other 1/3 of airflow • Scalenes – synergists to diaphragm – hold ribs 1 & 2 stationary in quiet respiration

Question 47

Intercostals

Answer 47

Intercostals

Question 48

_Respiratory Muscles_ • Normal quiet expiration – energy-saving passive process due to elasticity of lungs & thoracic cage – as muscles relax, structures recoil to original shape & size AIR FLOWS OUT • Forced expiration – rectus abdominis, internal intercostals, & others – increase abdominal pressure pushes viscera against diaphragm increasing thoracic pressure AIR FORCED OUT – helpful when… ?

Answer 48

_Respiratory Muscles_ • Normal quiet expiration – energy-saving passive process due to elasticity of lungs & thoracic cage – as muscles relax, structures recoil to original shape & size AIR FLOWS OUT • Forced expiration – rectus abdominis, internal intercostals, & others – increase abdominal pressure pushes viscera against diaphragm increasing thoracic pressure AIR FORCED OUT – helpful when… ?

Question 49

Respiratory Muscles

Answer 49

Respiratory Muscles

Question 50

_Respiratory Muscles_ • Valsalva maneuver—deep breath, hold it (close glottis), contract abdominal muscles to raise pressure & push organ contents out – childbirth, urination, defecation, vomiting

Answer 50

_Respiratory Muscles_ • Valsalva maneuver—deep breath, hold it (close glottis), contract abdominal muscles to raise pressure & push organ contents out – childbirth, urination, defecation, vomiting

Question 51

_Neural Control of Breathing_ • Exact mechanism for setting rhythm of respiration remains unknown (no pacemaker, like heart) • Depends on repetitive stimuli of skeletal muscles from CNS: cerebral (conscious) & reticular formation (unconscious)

Answer 51

_Neural Control of Breathing_ • Exact mechanism for setting rhythm of respiration remains unknown (no pacemaker, like heart) • Depends on repetitive stimuli of skeletal muscles from CNS: cerebral (conscious) & reticular formation (unconscious)

Question 52

Neural Control of Breathing

Answer 52

Neural Control of Breathing

Question 53

_Neural Control of Breathing_ • Ventral Respiratory Group - inspiratory & expiratory neurons: form reverberating circuit • Innervation – Phrenic nerve - diaphragm – Intercostal nerves - intercostal muscles * Dorsal Respiratory group – modifies VRG output based on other input (e.g. chemoreceptors) * Pontine RG – modifies based on higher brain input (e.g. emotional)

Answer 53

_Neural Control of Breathing_ • Ventral Respiratory Group - inspiratory & expiratory neurons: form reverberating circuit • Innervation – Phrenic nerve - diaphragm – Intercostal nerves - intercostal muscles * Dorsal Respiratory group – modifies VRG output based on other input (e.g. chemoreceptors) * Pontine RG – modifies based on higher brain input (e.g. emotional)

Question 54

_Central & Peripheral Input to Respiratory Centers_ • Hyperventilation—anxiety-triggered; rapid breathing expels CO2 too fast – blood CO2 drops, pH rises --\> cerebral arteries constrict – cerebral perfusion reduced --\> dizziness / fainting • Irritant receptors—airway’s epithelial cells – smoke, dust, pollen, excess mucus – trigger protective reflexes --\> bronchoconstriction, shallower breathing, breath-holding (apnea), coughing

Answer 54

_Central & Peripheral Input to Respiratory Centers_ • Hyperventilation—anxiety-triggered; rapid breathing expels CO2 too fast – blood CO2 drops, pH rises --\> cerebral arteries constrict – cerebral perfusion reduced --\> dizziness / fainting • Irritant receptors—airway’s epithelial cells – smoke, dust, pollen, excess mucus – trigger protective reflexes --\> bronchoconstriction, shallower breathing, breath-holding (apnea), coughing

Question 55

_Pressure, Resistance, & Airflow_ • Air flow governed by same principles as blood flow! – directly proportional to pressure difference betw/ two points – inversely proportional to resistance – F µ P/R • Atmospheric pressure drives respiration – weight of air above us! – 760 mm Hg (1 atm) at sea level

Answer 55

_Pressure, Resistance, & Airflow_ • Air flow governed by same principles as blood flow! – directly proportional to pressure difference betw/ two points – inversely proportional to resistance – F µ P/R • Atmospheric pressure drives respiration – weight of air above us! – 760 mm Hg (1 atm) at sea level

Question 56

_Pressure, Resistance, & Airflow_ • Inspiration: • Boyle’s law—at constant T, pressure (P) of given quantity of gas inversely proportional to volume (V) – if lung V increases, then internal (intrapulmonary) P decreases • pressure falls (below atmospheric), air moves into lungs – if lung V decreases, intrapulmonary P increases • pressure rises (above atmospheric), air moves out of lungs

Answer 56

_Pressure, Resistance, & Airflow_ • Inspiration: • Boyle’s law—at constant T, pressure (P) of given quantity of gas inversely proportional to volume (V) – if lung V increases, then internal (intrapulmonary) P decreases • pressure falls (below atmospheric), air moves into lungs – if lung V decreases, intrapulmonary P increases • pressure rises (above atmospheric), air moves out of lungs

Question 57

_Pressure, Resistance, & Airflow_ • Charles’s law—volume (V) of given quantity of gas directly proportional to its temperature (T) if constant P – cool air 16oC (60oF) increases in T when inspired – warmed to 37oC (99oF) when it reaches alveoli – inhaled V of 500 mL expands to 536 mL; this thermal expansion contributes to inflation of lungs

Answer 57

_Pressure, Resistance, & Airflow_ • Charles’s law—volume (V) of given quantity of gas directly proportional to its temperature (T) if constant P – cool air 16oC (60oF) increases in T when inspired – warmed to 37oC (99oF) when it reaches alveoli – inhaled V of 500 mL expands to 536 mL; this thermal expansion contributes to inflation of lungs

Question 58

_Pressure, Resistance & Airflow_ • Expiration (relaxed) – passive process - elastic recoil of thoracic cage – recoil compresses lungs – V decreases – raises P (+1 cm H2O) – air flows down pressure gradient --\> out of lungs • Forced breathing – accessory muscles raise P up to +40 cm H2O – LOTS of air à out of lungs!

Answer 58

_Pressure, Resistance & Airflow_ • Expiration (relaxed) – passive process - elastic recoil of thoracic cage – recoil compresses lungs – V decreases – raises P (+1 cm H2O) – air flows down pressure gradient --\> out of lungs • Forced breathing – accessory muscles raise P up to +40 cm H2O – LOTS of air à out of lungs!

Question 59

Pressure, Resistance & Airflow

Answer 59

Pressure, Resistance & Airflow

Question 60

_Pneumothorax_ • Pneumothorax—air in pleural cavity – thoracic wall punctured – inspiration sucks air through wound into pleural cavity – potential space becomes air-filled cavity – loss of negative intrapleural pressure: lungs recoil & collapse • Atelectasis—collapse of part (or all) of lung

Answer 60

_Pneumothorax_ • Pneumothorax—air in pleural cavity – thoracic wall punctured – inspiration sucks air through wound into pleural cavity – potential space becomes air-filled cavity – loss of negative intrapleural pressure: lungs recoil & collapse • Atelectasis—collapse of part (or all) of lung

Question 61

Pneumothorax

Answer 61

Pneumothorax