Respiratory System Fun Facts

Respiratory System Fun FactsRespiratory System Fun Facts The right lung is slightly larger than the left. The right lung is slightly larger than the left. Hairs in the nose help to clean the air we breathe as well as warming Hairs in the nose help to clean the air we breathe as well as warming

it. it. The highest recorded "sneeze speed" is 165 km per hour. The highest recorded "sneeze speed" is 165 km per hour. The surface area of the lungs is roughly the same size as a tennis The surface area of the lungs is roughly the same size as a tennis

court. court. The capillaries in the lungs would extend 1,600 kilometers if placed The capillaries in the lungs would extend 1,600 kilometers if placed

end to end. end to end. We lose half a liter of water a day through breathing. This is the We lose half a liter of water a day through breathing. This is the

water vapor we see when we breathe onto glass. water vapor we see when we breathe onto glass. A person at rest usually breathes between 12 and 15 times a minute. A person at rest usually breathes between 12 and 15 times a minute. Every minute we breathe, we take in 13 pints of air! That is we Every minute we breathe, we take in 13 pints of air! That is we

breathe about 6.15 liters of air every minute. breathe about 6.15 liters of air every minute. The breathing rate is faster in children and women than in men. The breathing rate is faster in children and women than in men.

Respiratory SystemRespiratory System

Chapter 13Chapter 13

Anatomy of the Respiratory SystemAnatomy of the Respiratory SystemA.A. Conduction SystemConduction System

1.1. Functions:Functions:a)a) Direct the airDirect the air- send air to air - send air to air

sacs (sacs (alveolialveoli))b)b) Humidify the airHumidify the air – add H2O – add H2O

vapor to the air (becomes damp)vapor to the air (becomes damp)c)c) Purify the airPurify the air – – MucusMucus filter the filter the

air of irritants and pathogens. air of irritants and pathogens. CiliaCilia push mucus to the back of push mucus to the back of the throat where it is swallowed the throat where it is swallowed and digested. and digested.

d)d) Warm the airWarm the air – Network of – Network of veins veins in back of nasal cavityin back of nasal cavity to bring to bring closer to body temperaturecloser to body temperature

Anatomy of the Respiratory SystemAnatomy of the Respiratory System2.2. Anatomical structures of conduction Anatomical structures of conduction

pathway(in order)pathway(in order)a)a) Nose with nostrilsNose with nostrils – openings – openings

through which air enters body.through which air enters body.b)b) Nasal cavityNasal cavity - Olfactory epithelium - Olfactory epithelium

located on the top of the cavity located on the top of the cavity and other mucus and veins and other mucus and veins present to clean and warm the air. present to clean and warm the air. ConchaeConchae located here, there are located here, there are three lobes (increase surface area) three lobes (increase surface area) for for more effective purificationmore effective purification..

c)c) Paranasal sinusesParanasal sinuses – openings in – openings in the skull bones that lighten the the skull bones that lighten the skull and provide skull and provide resonance resonance chambers for voicechambers for voice. Also . Also production site of mucus that production site of mucus that drains into nasal cavitydrains into nasal cavity. .

Anatomy of the Respiratory SystemAnatomy of the Respiratory System

d.d. PharynxPharynx – (5 inches) – (5 inches) common passagecommon passage for for digestive (food) and digestive (food) and respiratory (air) system.respiratory (air) system.

e.e. EpiglottisEpiglottis – forms the – forms the opening to the larynx. opening to the larynx. Will Will close when you close when you swallow so foodswallow so food does does not go down into the not go down into the respiratory passages. respiratory passages.

d.d. LarynxLarynx – “voice box”, formed by – “voice box”, formed by elastic cartilage. elastic cartilage. Location of Location of vocal folds (vocal cords)vocal folds (vocal cords) that that vibrate with expelled air forming vibrate with expelled air forming the sounds we make when we the sounds we make when we speak. speak. Glottis is the slit Glottis is the slit between the vocal cordsbetween the vocal cords..

e.e. TracheaTrachea – windpipe (4 inches – – windpipe (4 inches – down to T5). Lined with ciliated down to T5). Lined with ciliated mucosa mucosa to cleanto clean, mucus is , mucus is swept up to pharynx where it is swept up to pharynx where it is swallowed or spat out. The swallowed or spat out. The cilia are destroyedcilia are destroyed by cigarette by cigarette smoke and other pollutants.smoke and other pollutants.

http://en.wikipedia.org/wiki/File:Illu07_larynx02.jpg

TracheotomyTracheotomy

Trauma to the neck area Trauma to the neck area Obstructing tumors in the upper airwayObstructing tumors in the upper airway

Respiratory failure requiring long-term mechanical Respiratory failure requiring long-term mechanical breathing assistance, as in these cases: breathing assistance, as in these cases:

Spinal cord injury in the neck area Spinal cord injury in the neck area Severe lung infection or inflammationSevere lung infection or inflammation

Injury to the respiratory tract due to breathing in smoke or Injury to the respiratory tract due to breathing in smoke or steam or inhaling corrosive substances steam or inhaling corrosive substances

Birth defects of the trachea or larynx Birth defects of the trachea or larynx Foreign object blocking the trachea or larynxForeign object blocking the trachea or larynx

Anatomy of the Respiratory SystemAnatomy of the Respiratory Systemh.h. Primary bronchiiPrimary bronchii – Formed – Formed

when when trachea dividetrachea divide, one , one branch goes to each lung. branch goes to each lung. Bronchii subdivides within Bronchii subdivides within the lung, routing the air the lung, routing the air directly to the air sacs directly to the air sacs (alveloli).(alveloli).

i.i. LungsLungs – House the bronchial – House the bronchial trees (further branching). trees (further branching). There are There are 3 lobes in the right 3 lobes in the right lung and 2 lobes in the leftlung and 2 lobes in the left lung. lung. ApexApex is just deep to is just deep to your clavicle and the base is your clavicle and the base is by the diaphragm. The by the diaphragm. The pleural membranespleural membranes that that surround are important for surround are important for decreasing frictiondecreasing friction..

Flashcard Warm-up May 16Flashcard Warm-up May 16thth

The Respiratory Conduction SystemThe Respiratory Conduction System Trace the pathway of air through the Trace the pathway of air through the

conduction system until it reaches the alveoli conduction system until it reaches the alveoli of the lungsof the lungs• Your notes have these structures in orderYour notes have these structures in order

Anatomy of the Respiratory SystemAnatomy of the Respiratory System

B.B. Respiratory ZoneRespiratory Zone1.1. Function - area of gas Function - area of gas

exchange (exchange (oxygen in oxygen in and carbon dioxide outand carbon dioxide out))

2.2. StructuresStructuresa)a) Respiratory Respiratory

bronchiolesbronchioles – final – final branches of bronchi branches of bronchi where the alveoli (air where the alveoli (air sacs) are found.sacs) are found.

AlveoliAlveoli – air sacs, make up most of – air sacs, make up most of the lung tissue. Composed of a the lung tissue. Composed of a single cell layersingle cell layer (simple squamous). (simple squamous). Sacs are connected with alveolar Sacs are connected with alveolar pores pores provide alternate routes when provide alternate routes when some respiratory bronchioles are some respiratory bronchioles are blockedblocked. Sacs are completely . Sacs are completely surrounded with surrounded with capillaries (cobweb)capillaries (cobweb), , membranes fuse forming the air-blood membranes fuse forming the air-blood barrier. Oxygen (into the blood) and barrier. Oxygen (into the blood) and carbon dioxide (into alveoli sacs) carbon dioxide (into alveoli sacs) move across this membrane by move across this membrane by simple diffusionsimple diffusion (movement from high (movement from high to low concentrations).to low concentrations).

Anatomy of the Respiratory SystemAnatomy of the Respiratory Systemc.c. Surfactant producing cellSurfactant producing cell – – produce a lipid produce a lipid

molecule that coats the inside of the alveoli. molecule that coats the inside of the alveoli. Helps the sac remain “inflated” Helps the sac remain “inflated” by decreasing by decreasing the surface tension of waterthe surface tension of water..

BIG IDEABIG IDEA

““Volume changes lead to pressure Volume changes lead to pressure changes, which lead to the flow of gases changes, which lead to the flow of gases to equalize “to equalize “

Boyle's Law: Relationship Between Boyle's Law: Relationship Between Pressure and VolumePressure and Volume

.. • • These demonstrations illustrate These demonstrations illustrate Boyle's Law, which states that the Boyle's Law, which states that the

pressure of a gas is inversely proportional to the volumepressure of a gas is inversely proportional to the volume of its container. Thus, if you increase the volume of a container, the pressure will of its container. Thus, if you increase the volume of a container, the pressure will

decrease, and if you decrease thevolume of a container, the pressure will increase.decrease, and if you decrease thevolume of a container, the pressure will increase. ..

Intercostal musclesIntercostal muscles

Internal Internal pull rib pull rib cage incage in

External External pull rib pull rib cage up cage up and outand out

Respiratory PhysiologyRespiratory PhysiologyA.A. Pulmonary VentilationPulmonary Ventilation (breathing) – air moving in and (breathing) – air moving in and

out of the lungsout of the lungs1.1. Requires volume changes in the chest cavityRequires volume changes in the chest cavity, which , which

alters pressure of the gases in the lungs helping to alters pressure of the gases in the lungs helping to move the air out and in.move the air out and in.a.a. InspirationInspiration – diaphragm ( – diaphragm (moves inferiorly and moves inferiorly and

flattens outflattens out) and external intercostals ) and external intercostals contract contract this this increases the intrapulmonary volumeincreases the intrapulmonary volume (lung (lung size increases as chest cavity moves out) this size increases as chest cavity moves out) this causes a causes a decrease in pressure insidedecrease in pressure inside (like a little (like a little vacuum) and vacuum) and sucks air into the lungssucks air into the lungs. This will . This will continue till the intrapulmonary pressure equals continue till the intrapulmonary pressure equals atmospheric pressure. atmospheric pressure.

Respiratory PhysiologyRespiratory Physiologyb.b. ExpirationExpiration – Primarily a passive process as the – Primarily a passive process as the

diaphragm and external intercostals diaphragm and external intercostals relaxrelax (return to normal resting length) the (return to normal resting length) the intrapulmonary volume decreasesintrapulmonary volume decreases (causing an (causing an increase in pressure – increase in pressure – like deflating a floatlike deflating a float) ) when the pressure is higher than atmospheric when the pressure is higher than atmospheric pressure air moves out. If there is a narrowing pressure air moves out. If there is a narrowing of the passageways (of the passageways (asthmaasthma) or blockage with ) or blockage with mucus (mucus (bronchitis or pneumoniabronchitis or pneumonia), the ), the internal internal intercostals intercostals are needed to depress the rib cageare needed to depress the rib cageand and abdominalsabdominals can move against the can move against the diaphragm diaphragm

Respiratory PhysiologyRespiratory Physiology

2.2. The The collapse of the lungscollapse of the lungs is prevented is prevented due to the intrapleural pressure always due to the intrapleural pressure always being being negative (never equal to negative (never equal to atmospheric pressureatmospheric pressure). If this were to ). If this were to occur, such as when there is a puncture occur, such as when there is a puncture wound to the chest, the lungs will wound to the chest, the lungs will collapse, collapse, atelectasisatelectasis. .

Respiratory PhysiologyRespiratory Physiology3.3. Capacity and movement of Capacity and movement of

air in the lungs.air in the lungs.a.a. Tidal volumeTidal volume – amount of air – amount of air

exchanged during normal exchanged during normal breathing.breathing.

b.b. SpirometerSpirometer is used to is used to measure measure the respiratory capacitiesthe respiratory capacities of a of a person. Deficiencies in function person. Deficiencies in function can be important in determining can be important in determining respiratory diseases and the respiratory diseases and the extent of the damage. For extent of the damage. For example, emphysema affects example, emphysema affects expiration (ERV) and the expiration (ERV) and the residual volume is higher.residual volume is higher.

StethescopeStethescope can also be useful for diagnosing potential can also be useful for diagnosing potential problems. Listening for disruptions in problems. Listening for disruptions in bronchial soundsbronchial sounds (air rushing through the tubes) and (air rushing through the tubes) and vesicular soundsvesicular sounds (air (air filling alveoli) can indicate problems. filling alveoli) can indicate problems.

FORCEFUL INSPIRATION

FORCEFUL EXPIRATION

Air that is left in lungs

TV + IRV+ ERV=


B.B. External RespirationExternal Respiration – exchange of gases – exchange of gases between the between the alveoli and the capillariesalveoli and the capillaries..

1.1. There is always a higher concentration of There is always a higher concentration of oxygen in the alveoli and therefore the oxygen in the alveoli and therefore the oxygen diffuses passively into the capillary oxygen diffuses passively into the capillary bloodblood and binds to hemoglobin, turning the and binds to hemoglobin, turning the dark red blood of the pulmonary circuitdark red blood of the pulmonary circuit to a to a brighter red color for its return trip to the brighter red color for its return trip to the heart and distribution to the systemic circuit. heart and distribution to the systemic circuit.

Respiratory PhysiologyRespiratory Physiology2.2. Carbon dioxide is at a higher Carbon dioxide is at a higher

concentration in the blood as concentration in the blood as compared to the alveoli, compared to the alveoli, so this so this gas also diffuses into the alveoligas also diffuses into the alveoli. . Carbon dioxide is transported in Carbon dioxide is transported in the blood plasma as a the blood plasma as a bicarbonate ionbicarbonate ion (HCO3-), this (HCO3-), this helps maintain blood pHhelps maintain blood pH, but it is , but it is converted to carbonic acid converted to carbonic acid (H2CO3) before it diffuses out. (H2CO3) before it diffuses out.

http://video.about.com/asthma/How-Lungs-Function.htm

http://www.youtube.com/watch?v=HiT621PrrO0





Lung ModelLung Model 1. Answer the “Think” questions on 13A-D.1. Answer the “Think” questions on 13A-D. 2. ONE person from your group will get the 2. ONE person from your group will get the

ten layers to build your model.ten layers to build your model. 3. Color and cut out each layer (make sure 3. Color and cut out each layer (make sure

you do NOT cut out the star, square and circle you do NOT cut out the star, square and circle (these will act as a way to connect each layer)(these will act as a way to connect each layer)

Tomorrow we will analyze the structure, Tomorrow we will analyze the structure, function and things that can disrupt each layerfunction and things that can disrupt each layer


C.C. Internal RespirationInternal Respiration – exchange of – exchange of gases gases between capillaries and body tissuesbetween capillaries and body tissues. . This is again This is again primarily a passive primarily a passive exchangexchange due to different concentration e due to different concentration gradients in the tissue and the blood.gradients in the tissue and the blood.

Flashcard Warm-up May 17Flashcard Warm-up May 17thth Describe the pressure and volume Describe the pressure and volume

changes taking place during changes taking place during INSPIRATION and EXPIRATIONINSPIRATION and EXPIRATION

Respiratory PhysiologyRespiratory PhysiologyD.D. Control of respirationControl of respiration

1.1. Neural controlNeural controla.a. Respiratory centers in the brain are located in the Respiratory centers in the brain are located in the

medullamedulla and the and the ponspons. The medulla sets the . The medulla sets the basic rhythm and the pons smoothes out that basic rhythm and the pons smoothes out that rhythm. Normal respiration is about 12-15 rhythm. Normal respiration is about 12-15 breaths per minute.breaths per minute.

b.b. Stretch receptorsStretch receptors in the bronchioles help in the bronchioles help prevent prevent over inflationover inflation of the lungs and can stimulate the of the lungs and can stimulate the reaction of expiration.reaction of expiration.

c.c. If these respiratory centers are overcome with If these respiratory centers are overcome with drugs (drugs (morphine, sleeping pillsmorphine, sleeping pills) or ) or alcoholalcohol they they will stop and will stop and deathdeath occurs. occurs.

Respiratory PhysiologyRespiratory Physiology2.2. Other controlsOther controls

a.a. Physical factorsPhysical factors – exercise can – exercise can increase rate and depthincrease rate and depth of of breathing, also increased body temperature can increase breathing, also increased body temperature can increase rate and depth of breathing.rate and depth of breathing.

b.b. VolitionVolition - conscious control, necessary for - conscious control, necessary for swimming, swimming, singing, swallowingsinging, swallowing., but when oxygen gets too low ., but when oxygen gets too low involuntary controls kick in. (involuntary controls kick in. (controlled in CORTEX of controlled in CORTEX of brain)brain)world record for breath holding- 19 mins)world record for breath holding- 19 mins)

Mammalian diving reflex- allows mammals to hold their breath Mammalian diving reflex- allows mammals to hold their breath longer when we are in cold waterlonger when we are in cold water


c.c. Changes in Changes in blood pH due to carbon dioxideblood pH due to carbon dioxide levels. This level is the levels. This level is the most important most important stimulus for breathingstimulus for breathing in a healthy person. in a healthy person.

1.1. If If CO2CO2 levels levels decreasedecrease, this , this RAISESRAISES the pH ( the pH (too too basicbasic) of the blood leading to ) of the blood leading to hyperventilationhyperventilation (rapid (rapid respiratory rate) which respiratory rate) which expels more carbon dioxideexpels more carbon dioxide..

2.2. If If CO2CO2 levels are levels are too hightoo high, this , this LOWERSLOWERS pH ( pH (too too acid acid ) ) hypoventilationhypoventilation (slow, shallow breathing (slow, shallow breathing occurs), keeping more CO2 in the blood. occurs), keeping more CO2 in the blood.


3.3. Individuals with disorders that result in Individuals with disorders that result in continuous elevated CO2 levels continuous elevated CO2 levels ((emphysemaemphysema), the low oxygen levels ), the low oxygen levels become the primarily respiratory become the primarily respiratory stimulus. This is why these patients are stimulus. This is why these patients are given low levels of oxygen.given low levels of oxygen.


E.E. Disruptions in respiratory systemDisruptions in respiratory system1.1. System is particularly vulnerable to System is particularly vulnerable to airborne airborne

pathogenspathogens and inflammations due to infections. Ex. and inflammations due to infections. Ex. tonsillitis, rhinitistonsillitis, rhinitis..

2.2. Disorders that block or Disorders that block or obstructobstruct the pathways are the pathways are grouped together and called grouped together and called chronic obstructive chronic obstructive pulmonary diseasepulmonary disease (COPD). They typically include (COPD). They typically include a patient history of smoking which leads to a patient history of smoking which leads to increased levels of increased levels of dyspneadyspnea (labored breathing), (labored breathing), coughingcoughing, frequent infections, , frequent infections, hypoxiahypoxia (lack of (lack of oxygen in the tissues), and ultimately oxygen in the tissues), and ultimately respiratory respiratory failurefailure. These include:. These include:

a.a. EmphysemaEmphysema – Alveoli enlarge to the – Alveoli enlarge to the point where the walls can break point where the walls can break through to other alveoli, this creates through to other alveoli, this creates inflammation and fibrosis of the tissueinflammation and fibrosis of the tissue (decreased air capacity). (decreased air capacity). Lungs are Lungs are less elasticless elastic and airways can collapse, and airways can collapse, increased difficulty exhaling. increased difficulty exhaling. Characterized by a barrel chest due Characterized by a barrel chest due to over inflation of the lungs. Due to to over inflation of the lungs. Due to the air retention in the lungs the air retention in the lungs ((problems exhalingproblems exhaling) the oxygen ) the oxygen exchange is very efficient and initially exchange is very efficient and initially do not suffer from hypoxia. do not suffer from hypoxia.

b.b. Chronic bronchitisChronic bronchitis – – Increased Increased mucusmucus production to the point production to the point where it where it pools in the lower pools in the lower lungslungs, there is a , there is a decrease in decrease in gas exchangegas exchange and an and an increase risk of lung increase risk of lung infections. Due to the low infections. Due to the low efficiency of gas exchange efficiency of gas exchange these patients are these patients are frequently hypoxicfrequently hypoxic. .

Asthma is a chronic (long-Asthma is a chronic (long-term) lung disease that term) lung disease that inflames and narrows the inflames and narrows the airways. Asthma causes airways. Asthma causes recurring periods of recurring periods of wheezing (a whistling wheezing (a whistling sound when you breathe), sound when you breathe), chest tightness, shortness chest tightness, shortness of breath, and of breath, and coughing. . The coughing often occurs The coughing often occurs at night or early in the at night or early in the morning.morning.

http://www.nhlbi.nih.gov/health/health-topics/topics/cough/

Layers for Lung modelLayers for Lung model Ribs and vertebrae (posterior)Ribs and vertebrae (posterior) Ribs and sternum (anterior)Ribs and sternum (anterior) Mediastinum and diaphragmMediastinum and diaphragm Lungs (includes the pleural membranes)Lungs (includes the pleural membranes) BronchiBronchi AlveoliAlveoli Pulmonary arteriesPulmonary arteries Pulmonary veinsPulmonary veins HeartHeart

Layers for Lung modelLayers for Lung model 1. Ribs and vertebrae (posterior)1. Ribs and vertebrae (posterior) 2. Mediastinum and diaphragm2. Mediastinum and diaphragm 3. Posterior Lungs (includes the pleural membranes)3. Posterior Lungs (includes the pleural membranes) 4. Bronchi4. Bronchi 5. Alveoli5. Alveoli 6. Pulmonary arteries6. Pulmonary arteries 7. Pulmonary veins7. Pulmonary veins 8. Heart8. Heart 9. Anterior lungs9. Anterior lungs 10. Ribs and Sternum10. Ribs and Sternum

Question of the WeekQuestion of the Week What is heartburn and is it bad What is heartburn and is it bad

for me?for me? One in 10 Americans One in 10 Americans

experiences this once a week.experiences this once a week. Despite its name, heartburn Despite its name, heartburn

has nothing to do with the has nothing to do with the heart. Some of the symptoms, heart. Some of the symptoms, however, are similar to those however, are similar to those of a heart attack or heart of a heart attack or heart disease. Heartburn is an disease. Heartburn is an irritation of the esophagus that irritation of the esophagus that is caused by stomach acid. is caused by stomach acid. This can create a burning This can create a burning discomfort in the upper discomfort in the upper abdomen or below the breast abdomen or below the breast bone.bone.

Development of Respiratory Development of Respiratory System System

A.A. Infancy and ChildhoodInfancy and Childhood1.1. Lungs are Lungs are filled with fluid as a filled with fluid as a

fetusfetus and gas exchange in the and gas exchange in the placentaplacenta..

2.2. SurfactantSurfactant is produced (lipid is produced (lipid molecule) to keep the alveolar molecule) to keep the alveolar sacs expanded sacs expanded (lowers the (lowers the surface tension of watersurface tension of water). This ). This compound is not present in high compound is not present in high enough concentrations until 28 enough concentrations until 28 to 30 weeks for the infant to to 30 weeks for the infant to breath on its own. Infants are breath on its own. Infants are not up to full lung capacity until 2 not up to full lung capacity until 2 weeks of age weeks of age

Development of Respiratory Development of Respiratory SystemSystem

a.a. Infants born with Infants born with respiratory respiratory distressdistress (IRDS) can be treated (IRDS) can be treated with new equipment that with new equipment that maintains proper pressure maintains proper pressure levels and keeps alveoli levels and keeps alveoli expanded.expanded.

b.b. SIDSSIDS – some cases are – some cases are believed to be a believed to be a neural controlneural control problem many seems to be problem many seems to be linked with linked with heart abnormalitiesheart abnormalities..

The following have been linked to a baby's increased risk of SIDS:Sleeping on the stomachBeing around cigarette smoke while in the womb or after being bornSleeping in the same bed as their parents (co-sleeping)Soft bedding in the cribMultiple birth babies (being a twin, triplet, etc.)Premature birthHaving a brother or sister who had SIDSMothers who smoke or use illegal drugsBeing born to a teen motherShort time period between pregnanciesLate or no prenatal careLiving in poverty situations


4.4. Respiratory rate is high ~ 40 to Respiratory rate is high ~ 40 to 80 per minute.80 per minute.

B.B. Early childhood and adolescenceEarly childhood and adolescence1.1. Respiratory rate will decrease Respiratory rate will decrease

~ 30 per minute by age 5.~ 30 per minute by age 5.2.2. Additional alveoli developAdditional alveoli develop and and

lungs completely mature. If lungs completely mature. If individual begins individual begins smokingsmoking during this time the alveoli will during this time the alveoli will not develop and the lungs not develop and the lungs never completely maturenever completely mature..


3.3. Asthma may develop – chronically Asthma may develop – chronically inflamed bronchial passages.inflamed bronchial passages.

C.C. Adulthood and Old ageAdulthood and Old age1.1. Respiratory rate continues to Respiratory rate continues to

decreasedecrease, the chest cavity can , the chest cavity can become rigid and the lungs become rigid and the lungs less elastic. less elastic. Vital capacity Vital capacity decreasesdecreases to about 1/3 by age to about 1/3 by age 70. 70.

2.2. Ciliary movements and Ciliary movements and phagocyte activity decreasephagocyte activity decrease which leads to increased risk of which leads to increased risk of infection. infection.

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Respiratory System Fun Facts