Respiratory SystemRespiratory System

•Normal breathing rateNormal breathing rate 14-20 14-20 breaths/minbreaths/min

•Average person uses about .25 liters Average person uses about .25 liters of oxygen/minof oxygen/min

•Lungs hold about 4-6 liters of airLungs hold about 4-6 liters of air

•Oxygen is needed to metabolize Oxygen is needed to metabolize glucose and release water and carbon glucose and release water and carbon dioxidedioxide

3 Components of Respiration3 Components of RespirationBreathing Breathing entrance/exit of air to/from lungs entrance/exit of air to/from lungs2a. External respiration 2a. External respiration movement of air to blood movement of air to blood2b. Internal respiration 2b. Internal respiration movement of blood/oxygen movement of blood/oxygen to tissueto tissueAerobic cellular respiration Aerobic cellular respiration production of ATP in production of ATP in

cells from metabolism of glucosecells from metabolism of glucose

RespirationRespiration

Respiratory StructuresRespiratory Structures

Structure Structure Description Description Function Function

Nasal Cavity Nasal Cavity Hollow space in nose Hollow space in nose Filters and warms air Filters and warms air

Pharynx Pharynx Chamber behind oral cavity Chamber behind oral cavity Connection to surrounding Connection to surrounding regions regions

Glottis Glottis Opening to larynx Opening to larynx Passes air into larynx Passes air into larynx

Larynx Larynx Vocal chords Vocal chords Sound production Sound production

Trachea Trachea Tube that connects larynx Tube that connects larynx with bronchiwith bronchi

Passage of air to bronchiPassage of air to bronchi

Bronchi Bronchi Major divisions that Major divisions that

enter lungsenter lungs Passage of air to each lungPassage of air to each lung

BronchiolesBronchioles Small branched tubes that Small branched tubes that lead to alveoli lead to alveoli

Passage of air to Passage of air to

alveoli alveoli

Lungs Lungs Organs that occupy Organs that occupy

thoracic cavitythoracic cavity Gas exchange Gas exchange

Lungs

•Right lung has 3 lobes; left lung has 2 lobesRight lung has 3 lobes; left lung has 2 lobes•Lie at either side of the heartLie at either side of the heart•Base of the lung is broad and concave to fit into the convex diaphragmBase of the lung is broad and concave to fit into the convex diaphragm•Approximately 300 million alveoli in lungsApproximately 300 million alveoli in lungs•Alveoli increase the surface area of the lung so more oxygen can be taken upAlveoli increase the surface area of the lung so more oxygen can be taken up•Alveoli are bathed in surfactant, which reduces their surface tension and Alveoli are bathed in surfactant, which reduces their surface tension and prevents collapseprevents collapse•Gas filled alveoli are very light; a piece of lung usually floats on waterGas filled alveoli are very light; a piece of lung usually floats on water

3 lobes 3 lobes <---2 lobes<---2 lobes

Ear LobesEar Lobes

AlveoliAlveoli

AlveoliAlveoliAlveoli with attached arterioles Alveoli with attached arterioles

and venules (Capillaries)and venules (Capillaries)

•During ventilation, there is continuous air flow from pharynx to alveoli•The rib cage forms the top and sides of the thoracic cavity. The diaphragm forms the bottom of the thoracic cavity•The outer pleural membrane is attached to the rib cage and diaphragm

The Anatomy of Breathing

InspirationInspiration•Respiratory center is located in the medulla oblongataRespiratory center is located in the medulla oblongata•Neurons in the RC fire automatically in a rhythmic cycleNeurons in the RC fire automatically in a rhythmic cycle•Carbon dioxide levels in blood, lungs, or brain can cause changes in the Carbon dioxide levels in blood, lungs, or brain can cause changes in the activity of the RCactivity of the RC•When carbon dioxide levels rise, receptors in body send message to MO When carbon dioxide levels rise, receptors in body send message to MO to increase the firing of respiratory neuronsto increase the firing of respiratory neurons•MO sends impulses directly to the diaphragm and rib musclesMO sends impulses directly to the diaphragm and rib muscles•In relaxed state the, diaphragm is dome shaped.In relaxed state the, diaphragm is dome shaped.•When excited by the MO, the dome falls, intercostal muscles contract, When excited by the MO, the dome falls, intercostal muscles contract, pushing the rib cage outpushing the rib cage out•These actions create a vacuum of negative space in the lungs, the These actions create a vacuum of negative space in the lungs, the volume of the lungs increases, and air rushes involume of the lungs increases, and air rushes in•Humans inhale by negative pressureHumans inhale by negative pressure•Deep inspiration excites stretch receptors in alveoli, which in turn send a Deep inspiration excites stretch receptors in alveoli, which in turn send a message in MO to stop inhalationmessage in MO to stop inhalation

The Physiology of BreathingThe Physiology of Breathing

ExpirationExpirationDiaphragm and rib muscles relax and push upward and inward on the Diaphragm and rib muscles relax and push upward and inward on the lungslungsDeep expiration excites stretch receptors in alveoli, which in turn send a Deep expiration excites stretch receptors in alveoli, which in turn send a message in MO to stop inhalationmessage in MO to stop inhalation

The Physiology of BreathingThe Physiology of Breathing

Lung Capacity

•Lungs hold about 4-6 liters of airLungs hold about 4-6 liters of air•Tidal Volume Tidal Volume amount of air moved in and out in 1 breath (.1-.2 liters) amount of air moved in and out in 1 breath (.1-.2 liters)•Vital Capacity Vital Capacity Maximum amount of air taken in 1 breath (3.1 liters) Maximum amount of air taken in 1 breath (3.1 liters)•Residual VolumeResidual Volume After all air is expelled, there is still some air in After all air is expelled, there is still some air in lungs (<1 liter)lungs (<1 liter)

Healthy LungHealthy Lung Smoker’s lungSmoker’s lung

Internal & External RespirationInternal & External Respiration

External RespirationExternal RespirationAlveoli and blood vessels both consist of a thin layer of cellsAlveoli and blood vessels both consist of a thin layer of cellsBoth the alveoli and blood vessels allow for the free passage of oxygen, Both the alveoli and blood vessels allow for the free passage of oxygen, carbon dioxidecarbon dioxideDiffusion ALONE governs the exchange of oxygen and carbon dioxide at the Diffusion ALONE governs the exchange of oxygen and carbon dioxide at the alveolialveoliOxygen diffuses from the OOxygen diffuses from the O22 rich alveoli to the O rich alveoli to the O22 poor blood vessels poor blood vessels

Carbon dioxide diffuses from the COCarbon dioxide diffuses from the CO22 rich blood vessels to CO rich blood vessels to CO22 poor alveoli poor alveoli

Oxygen & HemoglobinOxygen & Hemoglobin

•Breathing at high altitude is less effective than at low Breathing at high altitude is less effective than at low altitudes because the concentration of oxygen is low, altitudes because the concentration of oxygen is low, therefore less Otherefore less O22 diffuses into the blood diffuses into the blood•Hemoglobin tends to attach to oxygen at cooler Hemoglobin tends to attach to oxygen at cooler temperatures and tends to release oxygen at warmer temperatures and tends to release oxygen at warmer temperaturestemperatures

•Blood that enters the tissues is bright red Blood that enters the tissues is bright red because the pigment hemoglobin turns red when because the pigment hemoglobin turns red when attached to oxygenattached to oxygen•Oxygen diffuses out of the blood and into the Oxygen diffuses out of the blood and into the tissues (at the capillaries) tissues (at the capillaries) •Carbon dioxide diffuses from the tissue to the Carbon dioxide diffuses from the tissue to the blood (at the capillaries)blood (at the capillaries)•Deoxygenated red blood cells have no oxygen; Deoxygenated red blood cells have no oxygen; turning the RBC blueturning the RBC blue•Red blood cells also pick up carbon dioxide and Red blood cells also pick up carbon dioxide and deliver it to the lungsdeliver it to the lungs

Internal RespirationInternal Respiration