PHYSIOLOGY EXTERNAL AND INTERNAL RESPIRATION 2 Respiration l

Respiration l Movement of gases between the environment and the body’s cells – The

Anatomy of the Respiratory System l Nasal Concha – Air eddies Air is cleaned

Larynx l Contains Vocal Cords – Connective tissue bands that tighten to create sound

Trachea l Conducts Air – Lined with pseudostratified ciliated columnar epithelium – Cilia can

Conducting System or Respiratory Tree l Primary Bronchi – Surrounded by O-shaped cartilagenous rings

Pleural Membranes l Visceral Pleura – Attached directly to the lungs l Parietal Pleura

Alveoli l Clustered at the ends of the terminal bronchioles l Makes up the

Capillaries l The alveoli are closely associated with an extensive network of capillaries –

Respiratory Membrane l Consists of – The Wall of the Alveoli – The Respiratory

Gas Laws l At sea level normal atmospheric pressure is 760 mm. Hg –

Dalton’s Law l The total pressure exerted by a mixture of gases is the

Gas Law The total pressure of a mixture of gases, is the sum of

Dalton’s Law l To find the partial pressure of any one gas in a

Gases Move from High Pressure to Low Pressure l Air flow occurs whenever there

Alveoli Composed of a single layer of epithelium called Type I cells l Type

Emphysema l Loss of elastic fibers for elastic recoil during expiration – Elastin is

Chronic Obstructive Pulmonary Disease (COPD) l Asthma, emphysema, chronic bronchitis

Pressure Gradients l Arterial Pressures – PO 2 = 100 mm. Hg – PCO

Hemoglobin l Oxygen is transported two – Dissolved in the plasma – Bound to

Hemoglobin l One hemoglobin molecule binds up to four oxygen molecules – Percent oxygen

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PHYSIOLOGY EXTERNAL AND INTERNAL RESPIRATION

Respiration l Movement of gases between the environment and the body’s cells – The exchange of air between the atmosphere and the lungs l l Known as ventilation or breathing Inspiration and Expiration – The exchanges of O 2 and CO 2 between the lungs and the blood – Transport of O 2 and CO 2 by the blood – The exchange of gases between blood and the cells

Anatomy of the Respiratory System l Nasal Concha – Air eddies Air is cleaned l Warmed l Humidified l l Tonsils and Adenoids – Lymph nodes that filter the air – Located in the nose, back of the throat, below the tongue

Larynx l Contains Vocal Cords – Connective tissue bands that tighten to create sound when air moves past them l Thyroid Cartilage – Sensitive to Testosterone levels

Trachea l Conducts Air – Lined with pseudostratified ciliated columnar epithelium – Cilia can be paralyzed by cigarette smoke l Surrounded by C-shaped Cartilagenous rings and the trachealis muscle – Esophagus is dorsal to the trachea l Approximately 4 inches long

Conducting System or Respiratory Tree l Primary Bronchi – Surrounded by O-shaped cartilagenous rings – Bifurcates to Secondary Bronchi in the lungs – Respiratory Bronchioles Surrounded by smooth muscles l Diameter of the airways becomes progressively smaller from the trachea to the bronchioles l The total cross-sectional area increases with each division of the airways l

Pleural Membranes l Visceral Pleura – Attached directly to the lungs l Parietal Pleura – Attaches to the visceral pleura – Also attaches to the thoracic cavity l Serous Fluid – Separates the two pleura and lubricates in order to decrease friction – Consistency of egg whites – Pleurisy occurs when the fluid decreases l The Function of the Pleural Membranes is to hold the lungs open

Alveoli l Clustered at the ends of the terminal bronchioles l Makes up the bulk of lung tissue l Primary function is the exchange of gases between themselves and the blood l Surrounded by elastic fibers – Creates Elastic Recoil

Capillaries l The alveoli are closely associated with an extensive network of capillaries – Blood vessels cover 80 -90% of the alveolar surface forming a continuous “sheet” of blood in close contact with the air-filled alveoli

Respiratory Membrane l Consists of – The Wall of the Alveoli – The Respiratory Space This is a fluid filled space l Pneumonia may cause the space to fill with more fluid than normal l – This decreases the ability to exchange gases – The Wall of the Capillary

Gas Laws l At sea level normal atmospheric pressure is 760 mm. Hg – On top of Mt. Everest Patm = 153 mm. Hg

Dalton’s Law l The total pressure exerted by a mixture of gases is the sum of the pressures exerted by the individual gases – 78% N 2 – 21% O 2 – 1% CO 2 l Partial Pressure of gases – The pressure of a single gas in a mixture

Gas Law The total pressure of a mixture of gases, is the sum of the pressures of the individual gases (Dalton’s Law) l Gases, singly or in a mixture, move from areas of higher pressure to areas of lower pressure l If the volume of a container of gas changes, the pressure of the gas will change in an inverse manner (Boyle’s Law) l

Dalton’s Law l To find the partial pressure of any one gas in a sample of air, multiply the atmospheric Pressure (Patm) by the gas’s relative contribution (%) to Patm. – Partial pressure of an atmospheric gas = l Patm X % of gas in atmosphere – Partial pressure of oxygen = 760 mm. Hg X 21% l PO 2 = 760 X 0. 21 = 160 mm. Hg

Gases Move from High Pressure to Low Pressure l Air flow occurs whenever there is a pressure gradient

Alveoli Composed of a single layer of epithelium called Type I cells l Type II alveolar cells l – Secretes surfactant – Surfactant decreases the surface tension of the water within the alveoli – Coats the inside of the alveoli – Cortisol causes the maturation of the type II cells in the fetal stage of development l Dust Cells – Phagocytes

Emphysema l Loss of elastic fibers for elastic recoil during expiration – Elastin is destroyed by elastase l An enzyme released by immune cells l Have more difficulty exhaling than inhaling

Chronic Obstructive Pulmonary Disease (COPD) l Asthma, emphysema, chronic bronchitis

Pressure Gradients l Arterial Pressures – PO 2 = 100 mm. Hg – PCO 2 = 40 mm. Hg l Alveolar Pressures – PO 2 = 100 mm. Hg – PCO 2 = 40 mm. Hg l Venous Pressures – PO 2 = 40 mm. Hg – PCO 2 = 45 mm. Hg l Tissue Pressures – PO 2 = 40 mm. Hg – PCO 2 = 45 mm. Hg

Hemoglobin l Oxygen is transported two – Dissolved in the plasma – Bound to hemoglobin ways in the blood l Mean Corpuscular Hemoglobin – Counting the RBC’s and quantifying the amount of hemoglobin per RBC l Hemoglobin Concentration or %

Hemoglobin l One hemoglobin molecule binds up to four oxygen molecules – Percent oxygen saturation l Globin – Proteins in the hemoglobin Alpha, beta, gamma and delta types l Adults have 2 alpha and 2 bets l Fetal Hb l – Two gamma and two alpha