Respiratory System Pt. IIRespiratory System Pt. II

Thomas AckermanThomas Ackerman

Juyoung JangJuyoung Jang

Liezel RiegoLiezel Riego

Quick ReviewQuick Review

– 6.4.1: Distinguish between 6.4.1: Distinguish between ventilation, ventilation, gas exchange, gas exchange, and and cell respiration.cell respiration.

– 6.4.2: Explain the need for a ventilation 6.4.2: Explain the need for a ventilation system.system.

– 6.4.3: Describe the features of the 6.4.3: Describe the features of the alveoli that adapt them to gas alveoli that adapt them to gas exchange.exchange.

– 6.4.4: Draw and label a diagram of the 6.4.4: Draw and label a diagram of the ventilation system, including trachea, ventilation system, including trachea, lungs, bronchi, bronchioles, and alveoli.lungs, bronchi, bronchioles, and alveoli.

Functions of respiratory Functions of respiratory systemsystem

Providing an area for gas exchange Providing an area for gas exchange between air and circulating bloodbetween air and circulating blood

Moving air to and from exchange Moving air to and from exchange surfacessurfaces

Protecting respiratory surfaces from Protecting respiratory surfaces from environmental variationsenvironmental variations

Organization of the respiratory Organization of the respiratory systemsystem

Includes the nose, nasal cavity, Includes the nose, nasal cavity, pharynx, larynx, trachea, bronchi, pharynx, larynx, trachea, bronchi, bronchioles, and alveolibronchioles, and alveoli

Respiratory tractRespiratory tract: carries air to and : carries air to and from alveolifrom alveoli

Upper respiratory tractUpper respiratory tract: filters and : filters and humidifies incoming airhumidifies incoming air

Lower respiratory tractLower respiratory tract: gas exchange: gas exchange

6.4.5: Mechanisms of 6.4.5: Mechanisms of VentilationVentilation

To inhale, the diaphragm contracts and flattens and the external To inhale, the diaphragm contracts and flattens and the external intercoastal muscles also contract and cause the ribcage to expand and intercoastal muscles also contract and cause the ribcage to expand and move up. move up. – The diaphragm contracts drops downwards. Thoracic volume The diaphragm contracts drops downwards. Thoracic volume

increases, lungs expand, and the pressure inside the lungs increases, lungs expand, and the pressure inside the lungs decreases, so that air flows into the lungs in response to the decreases, so that air flows into the lungs in response to the pressure gradient.pressure gradient.

– These movements cause the chest cavity to become larger and the These movements cause the chest cavity to become larger and the pressure to be smaller, so air rushes in from the atmosphere to the pressure to be smaller, so air rushes in from the atmosphere to the lungs. lungs.

To exhale, the diaphragm relaxes and moves up. In quiet breathing, the To exhale, the diaphragm relaxes and moves up. In quiet breathing, the external intercoastal muscles relax causing the elasticity of the lung external intercoastal muscles relax causing the elasticity of the lung tissue to recoil. tissue to recoil. – In forced breathing, the internal inercoastal muscles and abdominal In forced breathing, the internal inercoastal muscles and abdominal

muscles also contract to increase the force of the expiration. muscles also contract to increase the force of the expiration. – Thoracic volume decreases and the pressure inside the lungs Thoracic volume decreases and the pressure inside the lungs

increases. Air flows passively out of the lungs in response to the increases. Air flows passively out of the lungs in response to the pressure gradient. The ribs to move downward and backward pressure gradient. The ribs to move downward and backward causing the chest cavity to become smaller in volume and the causing the chest cavity to become smaller in volume and the pressure increases pushing air out of the lungs into the atmosphere. pressure increases pushing air out of the lungs into the atmosphere. (From (From AP Edition BiologyAP Edition Biology))

Gas exchange occurs across Gas exchange occurs across specialized respiratory specialized respiratory

surfacessurfaces Respiratory MediumRespiratory Medium: source : source

of Oof O22

– Air or and waterAir or and water Respiratory SurfaceRespiratory Surface: where : where

gases are exchanged with gases are exchanged with the surrounding environment the surrounding environment – Animals move OAnimals move O22 and CO and CO22 by by

passive transport (diffusion-passive transport (diffusion-higher concentration to higher concentration to lower concentration)lower concentration)

– Rate of diffusionRate of diffusion is is proportional to the surface proportional to the surface area where diffusion occurs area where diffusion occurs and inversely proportional to and inversely proportional to the square of the distance of the square of the distance of movement movement

– Thin and large surface area, Thin and large surface area, maximize gas exchangemaximize gas exchange

Mammalian respirationMammalian respiration Negative pressure Negative pressure

breathingbreathing: pulling air : pulling air instead of pushing it instead of pushing it out into the lungs.out into the lungs.– Lung volume increases Lung volume increases

as rib muscles and as rib muscles and diaphragm contractdiaphragm contract

Tidal volumeTidal volume: Volume : Volume of air inhalationof air inhalation

Vital capacityVital capacity: Max t.v. : Max t.v. in forced breathingin forced breathing

Residual volumeResidual volume: : amount of air amount of air remaining after forced remaining after forced breathingbreathing

Other Animals (NOT Other Animals (NOT mammals)mammals)

FishFish– GillsGills: outfoldings of body surface extended in water: outfoldings of body surface extended in water

Helps ventilation process: increasing flow of respiratory Helps ventilation process: increasing flow of respiratory medium over the respiratory surfacemedium over the respiratory surface

Countercurrent exchangeCountercurrent exchange: makes it possible to transfer O2 : makes it possible to transfer O2 to the blood in waterto the blood in water

– Results in diffusion gradient for O2 over entire length of Results in diffusion gradient for O2 over entire length of capillaries in gillscapillaries in gills

– As blood moves through gill capillaries, loaded with O2, even As blood moves through gill capillaries, loaded with O2, even through against concentration gradientthrough against concentration gradient

– More than 80% in O2 in water is able to be diffusedMore than 80% in O2 in water is able to be diffused InsectsInsects

– Tracheal systemTracheal system: air tubes branching through body: air tubes branching through body Folded internal respiratory surfaceFolded internal respiratory surface

– TrachaeTrachae – opens outside – opens outside– Open circulatory systemOpen circulatory system

Other Animals (NOT Other Animals (NOT mammals)mammals)

BirdsBirds– 8 or 9 airsacs and lungs8 or 9 airsacs and lungs

Bellows keeping air flowingBellows keeping air flowing Not to be confused with alveolar sacsNot to be confused with alveolar sacs

AmphibiansAmphibians– Positive pressure breathingPositive pressure breathing: air is forced through lungs: air is forced through lungs– During cycle, muscles lower in oral cavity, drawing air During cycle, muscles lower in oral cavity, drawing air

through nostrilsthrough nostrils– Closed nostrils and mouth, floor of oral cavity risesClosed nostrils and mouth, floor of oral cavity rises– Air is forced down tracheaAir is forced down trachea– Elastic recoil of lungs and compression of muscular body Elastic recoil of lungs and compression of muscular body

wall force air back out of the lungswall force air back out of the lungs

Marine MammalsMarine Mammals What happens when respiratory What happens when respiratory

medium is not accessible medium is not accessible continuously?continuously?

Weddell seal (and other “diving” Weddell seal (and other “diving” mammals):mammals):– Ability to store large amounts of OAbility to store large amounts of O22

Twice as much per kg of body mass Twice as much per kg of body mass as humansas humans

5% in lungs, 70% in blood5% in lungs, 70% in blood Twice as much blood volume per kg Twice as much blood volume per kg

of body mass as humansof body mass as humans– Huge spleenHuge spleen

Stores 24L of bloodStores 24L of blood– High concentration of High concentration of myoglobinmyoglobin

(oxygen-storing protein) in muscles(oxygen-storing protein) in muscles 25% of O25% of O22 in muscle, 13% in humans in muscle, 13% in humans

– Swim with little muscular effort, Swim with little muscular effort, buoyancybuoyancy

– Heart rate and OHeart rate and O22 consumption rate consumption rate decrease while divingdecrease while diving

– Blood supply to most muscles Blood supply to most muscles either restricted or shut down either restricted or shut down completelycompletely

Breathing ventilates the Breathing ventilates the lungslungs

Control of breathingControl of breathing– Breathing control centers: medulla oblongata and pons.Breathing control centers: medulla oblongata and pons.– Pons sets basic breathing rhythm.Pons sets basic breathing rhythm.– Sensors in aorta and carotid arteries monitor OSensors in aorta and carotid arteries monitor O2 2 and COand CO22

concentrationsconcentrations– Negative-feedback mechanism prevents lungs from over-Negative-feedback mechanism prevents lungs from over-

expanding.expanding.– Medulla regulates breathing activity in response to pH changes of Medulla regulates breathing activity in response to pH changes of

tissue fluid (cerebrospinal).tissue fluid (cerebrospinal). COCO22 diffuses from blood to fluid, reacts with water and carbonic acid, diffuses from blood to fluid, reacts with water and carbonic acid,

lowering pHlowering pH– Increases depth and rate of breathingIncreases depth and rate of breathing– Excess COExcess CO22 released through exhalation released through exhalation– This happens during exerciseThis happens during exercise

– OO22 concentrations have little effect concentrations have little effect– When OWhen O22 is extremely depressed (high altitudes), O is extremely depressed (high altitudes), O22 sensors in aorta and sensors in aorta and

carotid arteries in neck send signals to breathing control centerscarotid arteries in neck send signals to breathing control centers Increases breathing rateIncreases breathing rate

– Normally, rise in CONormally, rise in CO22 concentration accompanies fall in O concentration accompanies fall in O22 concentrationconcentration

Control of breathing (Cont.)Control of breathing (Cont.)

Hyperventilation: tricking the Hyperventilation: tricking the breathing centerbreathing center– Excessive, deep, rapid breathing purges Excessive, deep, rapid breathing purges

blood of too much COblood of too much CO22

– Breathing center temporarily stops Breathing center temporarily stops sending impulses to rib muscles and sending impulses to rib muscles and diaphragmdiaphragm

– Breathing stops until COBreathing stops until CO22 levels increase levels increase (or O2 levels decrease) enough so that (or O2 levels decrease) enough so that the breathing center turns back onthe breathing center turns back on

Respiratory pigments bind and Respiratory pigments bind and transport gasestransport gases

Oxygen has low solubility in water and in bloodOxygen has low solubility in water and in blood Respiratory pigmentsRespiratory pigments: transport gases and help : transport gases and help

buffer the bloodbuffer the blood Greatly increase the amount of OGreatly increase the amount of O2 2 the blood can the blood can

carrycarry HemoglobinHemoglobin - An iron containing protein in red-blood - An iron containing protein in red-blood

cell that reversibly binds oxygen (“reversibly” just cell that reversibly binds oxygen (“reversibly” just means loading oxygen in the lungs and unloading it means loading oxygen in the lungs and unloading it in the rest of the body)in the rest of the body)– Four protein subunits with iron in the middle of each Four protein subunits with iron in the middle of each

subunitsubunit– Each hemoglobin can bind to four molecules of OEach hemoglobin can bind to four molecules of O22

– Binding of OBinding of O22 to once subunit causes the other three to to once subunit causes the other three to change their shape slightlychange their shape slightly

The Bohr ShiftThe Bohr Shift

An effect that releases An effect that releases oxygen by hemoglobinoxygen by hemoglobin

Lowers the affinity for Lowers the affinity for oxygen because of oxygen because of drop in pH and an drop in pH and an increase in partial increase in partial pressurepressure– This causes the This causes the

hemoglobin to release hemoglobin to release more oxygen which can more oxygen which can be used for cellular be used for cellular respirationrespiration

Carbon Dioxide Carbon Dioxide TransportTransport

Other Functions for Other Functions for HemoglobinHemoglobin– Helps transport COHelps transport CO22

– Assists in buffering- prevents Assists in buffering- prevents harmful changes in blood pHharmful changes in blood pH

Process of TransportationProcess of Transportation– COCO22 diffuses into red blood diffuses into red blood

cells (90%) and plasma(7%)cells (90%) and plasma(7%)– Some COSome CO22 is picked up by is picked up by

hemoglobin but most react in hemoglobin but most react in water forming carbonic acid water forming carbonic acid (H2CO3)(H2CO3)

– Carbonic acid dissociates into Carbonic acid dissociates into a Hydrogen ion (Ha Hydrogen ion (H++) and ) and bicarbonate ion (HCO3-)bicarbonate ion (HCO3-)

– Hemoglobin binds most of the Hemoglobin binds most of the HH++ preventing it from preventing it from acidifying the blood and acidifying the blood and starting the Bohr Shiftstarting the Bohr Shift

Carbon Dioxide Carbon Dioxide Transport (Cont.)Transport (Cont.)

The carbonic acid (HThe carbonic acid (H22COCO33) ) diffuses into the plasmadiffuses into the plasma

Blood flows through the lungs so Blood flows through the lungs so the whole process is rapidly the whole process is rapidly reversed reversed – Diffusion of CODiffusion of CO22 out of the out of the

blood shifts the chemical blood shifts the chemical equilibrium in favor of the equilibrium in favor of the conversion of bicarbonate ion conversion of bicarbonate ion (HCO(HCO33-) to CO-) to CO22

Bicarbonate ion Bicarbonate ion (HCO(HCO33-) -) diffuses diffuses from plasma into the red blood from plasma into the red blood cellscells– This then combines with a This then combines with a

hydrogen ion (H+) to form hydrogen ion (H+) to form (H(H22COCO33) ) , a carbonic acid, a carbonic acid

Carbonic acid is converted back Carbonic acid is converted back to to COCO22 and water and water

COCO22 is then unloaded into the is then unloaded into the alveolar space which then will be alveolar space which then will be expelled during exhalationexpelled during exhalation

Pressure and VentilationPressure and Ventilation The direction of airflow is determined by the The direction of airflow is determined by the

relation of atmospheric pressure and relation of atmospheric pressure and intrapulmonary pressureintrapulmonary pressure

Intrapulmonary pressureIntrapulmonary pressure is the pressure inside the is the pressure inside the alveolialveoli

Respiratory pressureRespiratory pressure– Low when you are relaxed and breathing quietlyLow when you are relaxed and breathing quietly– Drops when you inhaleDrops when you inhale– Increases when you exhaleIncreases when you exhale

Atmospheric pressure decreases with increasing Atmospheric pressure decreases with increasing altitude and so do the partial pressure of gases altitude and so do the partial pressure of gases including oxygenincluding oxygen

– Partial pressure:Partial pressure: measure of the concentration of one gas measure of the concentration of one gas in a mixture of gases; pressure exerted by particular gas in a mixture of gases; pressure exerted by particular gas in a mixture of gases (pressure exerted by oxygen in air)in a mixture of gases (pressure exerted by oxygen in air)

Gas exchange at High Altitude Gas exchange at High Altitude (HL)(HL)

Partial air pressure of oxygen at high Partial air pressure of oxygen at high altitude is lower than at sea levelaltitude is lower than at sea level– EffectsEffects

Hemoglobin may not become fully saturated as Hemoglobin may not become fully saturated as it passes through the lungsit passes through the lungs

tissues of the body may not be adequately tissues of the body may not be adequately supplied with oxygen supplied with oxygen

Mountain SicknessMountain Sickness– with muscular weakness, rapid pulse, nausea with muscular weakness, rapid pulse, nausea

and headachesand headaches– can be avoided by ascending gradually to can be avoided by ascending gradually to

allow the body to acclimatize to high altitudeallow the body to acclimatize to high altitude

Gas exchange at High Altitude Gas exchange at High Altitude (Cont.)(Cont.)

During acclimatization the ventilation rate During acclimatization the ventilation rate increasesincreases– Extra red blood cells are produced, increasing the Extra red blood cells are produced, increasing the

hemoglobin content of the bloodhemoglobin content of the blood– Muscles produce more myoglobin and develop a Muscles produce more myoglobin and develop a

denser capillary networkdenser capillary network– These changes help to supply the body with enough These changes help to supply the body with enough

oxygenoxygen Some people who are native to high altitude show Some people who are native to high altitude show

other adaptations:other adaptations:– a high lung capacity with a large surface area for gas a high lung capacity with a large surface area for gas

exchangeexchange– larger tidal volumes and hemoglobin with an larger tidal volumes and hemoglobin with an

increased affinity for oxygenincreased affinity for oxygen

Changes in the respiratory Changes in the respiratory systemsystem

At birthAt birth– Before delivery, fetal lungs are fluid-filled and Before delivery, fetal lungs are fluid-filled and

collapsed.collapsed.– At first breath, lungs inflate and never collapse At first breath, lungs inflate and never collapse

completely thereafter.completely thereafter. Aging:Aging:

– Less efficient in elderlyLess efficient in elderly Elastic tissue deteriorates, lowering the vital capacity of Elastic tissue deteriorates, lowering the vital capacity of

the lungs.the lungs. Movements of the chest are restricted by arthritic Movements of the chest are restricted by arthritic

changes and decreased flexibility of costal cartilages.changes and decreased flexibility of costal cartilages. Some degree of emphysema is generally present.Some degree of emphysema is generally present.

AsthmaAsthma Chronic long term lung Chronic long term lung

disease that inflames disease that inflames and narrows airwaysand narrows airways

The muscles around The muscles around the bronchi tighten the bronchi tighten which causes less air which causes less air to flow to your lungsto flow to your lungs

Causes-pollen, pets, Causes-pollen, pets, dust mites, fungi etc.dust mites, fungi etc.– Being “too clean” Being “too clean”

causes the immune causes the immune system to react against system to react against harmless substancesharmless substances

Study QuestionsStudy Questions Why is the position of lung tissues within the body an advantage Why is the position of lung tissues within the body an advantage

for terrestrial animals?for terrestrial animals? Explain how countercurrent exchange maximizes the ability of fish Explain how countercurrent exchange maximizes the ability of fish

gills to extract dissolved O2 from water gills to extract dissolved O2 from water How does an increase in the CO2 concentration in the blood affect How does an increase in the CO2 concentration in the blood affect

the pH of cerebrospinal fluid?the pH of cerebrospinal fluid? A slight decrease in blood pH causes the heart’s pacemaker to A slight decrease in blood pH causes the heart’s pacemaker to

speed up. What is the function of this control mechanism?speed up. What is the function of this control mechanism? How does breathing differ in mammals and birds?How does breathing differ in mammals and birds? What determines whether O2 or CO2 diffuse into or out of the What determines whether O2 or CO2 diffuse into or out of the

capillaries in the tissues and near the alveolar spaces? Explain.capillaries in the tissues and near the alveolar spaces? Explain. How does the Bohr shift help deliver O2 to very active tissues?How does the Bohr shift help deliver O2 to very active tissues? Carbon dioxide within red blood cells in the tissue capillaries Carbon dioxide within red blood cells in the tissue capillaries

combines with water, forming carbonic acid. What causes the combines with water, forming carbonic acid. What causes the reverse of this reaction in red blood cells in capillaries near the reverse of this reaction in red blood cells in capillaries near the alveolar spaces?alveolar spaces?

Describe three (3) adaptations that enable Weddell seals to stay Describe three (3) adaptations that enable Weddell seals to stay underwater much longer than humans can.underwater much longer than humans can.

Suggested AnswersSuggested Answers If lungs extended into environment, dry out, diffusion would stopIf lungs extended into environment, dry out, diffusion would stop Results in diffusion gradient for OResults in diffusion gradient for O22 over entire length of capillaries over entire length of capillaries

in gills, opposite flow allows for Oin gills, opposite flow allows for O22 loading, despite against concent. loading, despite against concent. grad.grad.

> CO> CO22 = < pH = < pH Increases heart rate increases rate at which CO2 is delivered to Increases heart rate increases rate at which CO2 is delivered to

lungs, where COlungs, where CO22 is removed. is removed. Air passes through lungs in one direction in birds; direction Air passes through lungs in one direction in birds; direction

reverses in mammals between inhalation and exhalation.reverses in mammals between inhalation and exhalation. Differences in partial pressure; gases diffuse higher>lower partial Differences in partial pressure; gases diffuse higher>lower partial

press.press. Causes hemoglobin to release more OCauses hemoglobin to release more O22 at lower pH, in vicinity of at lower pH, in vicinity of

tissues w/ high resp. rates and COtissues w/ high resp. rates and CO2 2 release.release. Decrease in CODecrease in CO22 concent. in plasma as it diffuses into alveolar concent. in plasma as it diffuses into alveolar

spaces causes carbonic acid within RBC to break down, yielding spaces causes carbonic acid within RBC to break down, yielding COCO22, diffuses into plasma, diffuses into plasma

Blood volume relative to body mass; larger spleen; more myoglobin Blood volume relative to body mass; larger spleen; more myoglobin in muscles; heart rate and metabolic rate decrease during divesin muscles; heart rate and metabolic rate decrease during dives