Respiratory System Anatomy and Physiology. Parts of the Respiratory System Nasal Cavity Pharynx – common passage of food and air Larynx – 8 rings.

Respiratory SystemRespiratory System

Anatomy and PhysiologyAnatomy and Physiology

Parts of the Respiratory SystemParts of the Respiratory System Nasal CavityNasal Cavity Pharynx – common passage of food and airPharynx – common passage of food and air Larynx – 8 rings or cartilage and the mucous Larynx – 8 rings or cartilage and the mucous

membrane has 2 pairs of folds – vocal cords – membrane has 2 pairs of folds – vocal cords – vibrate for speechvibrate for speech

Epiglottis – flap of cartilage that closes off the larynx Epiglottis – flap of cartilage that closes off the larynx when swallowing so that food goes down the when swallowing so that food goes down the esophagus and not to the lungs (if anything but air esophagus and not to the lungs (if anything but air enters the larynx – it causes us to cough)enters the larynx – it causes us to cough)

Thyroid cartilage – big piece of shield-shaped Thyroid cartilage – big piece of shield-shaped cartilage in front of the larynx (Adam’s apple) – only cartilage in front of the larynx (Adam’s apple) – only males havemales have

Trachea – windpipe (4”) – lined with ciliated Trachea – windpipe (4”) – lined with ciliated mucosae – reinforced with cartilage rings to keep it mucosae – reinforced with cartilage rings to keep it openopen

Parts ContinuedParts Continued Bronchi – trachea divides into 2 to go to Bronchi – trachea divides into 2 to go to

each lungeach lung Bronchioles or bronchiole tree – smaller Bronchioles or bronchiole tree – smaller

and smaller branchesand smaller branches Alveoli – air sacs lined with epitheliumAlveoli – air sacs lined with epithelium Lungs – most of the lungs are made of the Lungs – most of the lungs are made of the

alveoli (millions) with connective tissuealveoli (millions) with connective tissue Left lung – 2 lobes/ Right lung – 3 lobesLeft lung – 2 lobes/ Right lung – 3 lobes Covered by serous membrane (pleura) – Covered by serous membrane (pleura) –

keep the lungs from rubbing against the keep the lungs from rubbing against the thoracic cavity and adhere lungs to the thoracic cavity and adhere lungs to the chest wall for inflation during breathingchest wall for inflation during breathing

AlveoliAlveoli Happens from the alveoli to the capillaries Happens from the alveoli to the capillaries

by simple diffusion (oxygen enters the by simple diffusion (oxygen enters the capillaries and carbon dioxide leaves them capillaries and carbon dioxide leaves them and enters the alveoli)and enters the alveoli)

Macrophages move in and out and destroy Macrophages move in and out and destroy bacteria that get inbacteria that get in

Embedded in the epithelial cells are cells Embedded in the epithelial cells are cells that make lung surfactant – lipid coating that make lung surfactant – lipid coating that keeps alveoli from collapsingthat keeps alveoli from collapsing

Surface area for gas exchange of each Surface area for gas exchange of each lung is about the size of 1 tennis courtlung is about the size of 1 tennis court

Alveoli

BreathingBreathing

Diaphragm contracts (pulls down)Diaphragm contracts (pulls down) The volume in the lungs increases so the The volume in the lungs increases so the

pressure decreasespressure decreases Atmospheric pressure is higher than the Atmospheric pressure is higher than the

pressure in the lungs so it automatically pressure in the lungs so it automatically flows inflows in

Intercostal muscles also expand the ribs Intercostal muscles also expand the ribs aiding in lung expansion and the decrease aiding in lung expansion and the decrease in pressure (lungs adhere to the thoracic in pressure (lungs adhere to the thoracic wall by the pleural membrane)wall by the pleural membrane)

Breathing ContinuedBreathing Continued Tidal VolumeTidal Volume – volume of air inhaled and – volume of air inhaled and

exhaled (500 mls/1pt.)exhaled (500 mls/1pt.) Inspiratory Reserve VolumeInspiratory Reserve Volume – amount that can – amount that can

forcibly be taken in over tidal volume (2000-3000 forcibly be taken in over tidal volume (2000-3000 mls)mls)

Vital capacityVital capacity – Maximum air the lungs can hold – Maximum air the lungs can hold (4500 mls)(4500 mls)

Expiratory Reserve VolumeExpiratory Reserve Volume – amount that can – amount that can be forcibly exhaled after tidal expiration (about be forcibly exhaled after tidal expiration (about 1000 mls)1000 mls)

Residual VolumeResidual Volume – amount of air left in the – amount of air left in the lungs even after forced expiration (about 1000 lungs even after forced expiration (about 1000 mls) – allow gas exchange between breaths and mls) – allow gas exchange between breaths and keeps alveoli inflatedkeeps alveoli inflated

Sneezing and coughing clear the air passages of Sneezing and coughing clear the air passages of debris and excess mucousdebris and excess mucous

Gas ExchangeGas Exchange Oxygen diffuses from inside the Oxygen diffuses from inside the

alveoli (20%) to the capillaries of the alveoli (20%) to the capillaries of the lungs (~0%)lungs (~0%)

Most of it is picked up by hemoglobinMost of it is picked up by hemoglobin After the blood is pumped to the After the blood is pumped to the

body and reaches the capillaries of body and reaches the capillaries of the body’s tissues – the oxygen is the body’s tissues – the oxygen is dumped off by hemoglobin and dumped off by hemoglobin and diffuses out of the RBC into the diffuses out of the RBC into the interstitial fluid surrounding the cells interstitial fluid surrounding the cells – it then diffuses into the cells– it then diffuses into the cells

How does more Oxygen Get to How does more Oxygen Get to the Cells that Need it the Most?the Cells that Need it the Most?

i.e. cells doing the most worki.e. cells doing the most work1.1. Blood is diverted to the most active areas Blood is diverted to the most active areas

(precap. sphincters shut off blood to (precap. sphincters shut off blood to certain areas not in use)certain areas not in use)

2.2. Hemoglobin drops off Oxygen quicker in Hemoglobin drops off Oxygen quicker in areas of low oxygen and high COareas of low oxygen and high CO2 2 (higher (higher acidity)acidity)

3.3. The higher the concentration difference The higher the concentration difference of oxygen between blood and cells, the of oxygen between blood and cells, the faster the rate of diffusionfaster the rate of diffusion

Control of RespirationControl of Respiration Controlled by the autonomic nervous system Controlled by the autonomic nervous system Normally breath 12-15 times/minuteNormally breath 12-15 times/minute Do have some conscious control over breathing Do have some conscious control over breathing

but autonomic centers will ignore information if but autonomic centers will ignore information if ph of blood is low (can’t hold your breath until ph of blood is low (can’t hold your breath until you die)you die)

Mostly controlled by level of carbon dioxide in the Mostly controlled by level of carbon dioxide in the blood (pH) – act on the medulla oblongata in the blood (pH) – act on the medulla oblongata in the brainbrain

Oxygen concentration is also measured in the Oxygen concentration is also measured in the aorta and carotid arteries which send signals to aorta and carotid arteries which send signals to the medulla – only when oxygen is dangerously the medulla – only when oxygen is dangerously lowlow

Hyperventilating – breathing real fast – lose too Hyperventilating – breathing real fast – lose too much carbon dioxide too fast, blood becomes a much carbon dioxide too fast, blood becomes a little basic and breathing may stop – breath into a little basic and breathing may stop – breath into a bag to increase carbon dioxide levelsbag to increase carbon dioxide levels

Lung DiseaseLung Disease COPD – usually caused by smoking – hard to COPD – usually caused by smoking – hard to

breath, coughing, lung infections, don’t properly breath, coughing, lung infections, don’t properly get rid of carbon dioxideget rid of carbon dioxide– Emphysema - lungs become less elastic and airways Emphysema - lungs become less elastic and airways

collapse during expiration so air can’t get out – take collapse during expiration so air can’t get out – take huge amounts of energy to exhalehuge amounts of energy to exhale

– Chronic Bronchitis – mucous membranes become Chronic Bronchitis – mucous membranes become inflamed and excess mucus clogs air passagesinflamed and excess mucus clogs air passages

Lung cancer – 1/3 of all cancer deaths – over 90% Lung cancer – 1/3 of all cancer deaths – over 90% of people with lung cancer smoked – about 15 of people with lung cancer smoked – about 15 carcinogens in cigarette smoke – metastasizes carcinogens in cigarette smoke – metastasizes quickly with a 7% survival ratequickly with a 7% survival rate