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The Respiratory System. Respiratory System Functions Pulmonary ventilation  movement of air into and out of lungs “breathing” External respiration 

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Presentation on theme: "The Respiratory System. Respiratory System Functions Pulmonary ventilation  movement of air into and out of lungs “breathing” External respiration "— Presentation transcript:

1 The Respiratory System

2 Respiratory System Functions Pulmonary ventilation  movement of air into and out of lungs “breathing” External respiration  movement of O2 and CO2 between blood and lungs Transport of respiratory gases  transport of O2 and CO2 between tissue and lungs Internal respiration  movement of O2 and CO2 between blood and tissue Olfaction

3 Respiratory System Upper respiratory system Lower respiratory system Conducting Zone Respiratory Zone Respiratory mucosa – Respiratory defense system (adaptive or innate?)

4 Upper Respiratory External nares Nasal cavity – Warm, moisten & filter air (Nasal conchae, surface area) – Detect smell (olfactory epithelium) – Modifying sounds by resonance Pharynx  both respiratory & digestive pathway

5 Larynx Provide an open airway to route air and food properly Produce a voice

6 Sound Production Phonation Articulation

7 Trachea “windpipe” Lined in mucosa with cilia that propel debris laden mucus to the pharynx – (destroyed by smoking, use coughing instead)

8 Lungs

9 Lobes – Superior, middle, inferior – Superior, inferior – Oblique fissures – Cardiac notch

10 Bronchial Tree Primary bronchi Secondary bronchi Tertiary bronchi – Bronchopulmonary segment Bronchioles – Bronchodilation – Bronchoconstrction Terminal bronchiole

11 Pulmonary lobule Lymph vessel, arteriole, and venule Respiratory bronchioles

12 Alveoli Alveolar duct Alveolar sacs Alveoli – Capillaries – Elastic tissue

13 Alveoli Type I alveolar cells Alveolar macrophage Type II alveolar cells (septal cells) – Surfactant – Surface tension – Respiratory distress syndrome (RDS)

14 Respiratory Physiology Pulmonary ventilation “breathing” – Inhalation – Exhalation External (pulmonary) respiration Internal (tissue) respiration Problems – Hypoxia Ventilation-perfusion coupling – Anoxia

15 Respiratory Gas Laws

16 Boyle’s Law: P=1/V

17 Inhalation (inspiration) Requires changes in air pressure. At sea level air pressure is 1 atmosphere (atm) or 760mmHg. During inhalation pressure must drop below 1 atm. Gas particles move from an area of high pressure to an area of low pressure (diffusion). Increasing the volume of a quantity of gas leads to a drop in pressure—an inverse relationship.

18 Respiration Pressure measurements – Atmospheres (atm)  pressure at sea level – 760mm Hg / torr = 1atm – cm H 2 0 = 1 atm – 15 PSI = 1 atm

19 Respiration Atmospheric pressure Intrapulmonary pressure Intrapleural pressure

20 Muscles of inspiration Diaphragm External intercostals During forceful breathing – Sternocleidomastoid – Scalenes – Pectoralis minor

21 Muscles of expiration Relaxation of inspiratory muscles During forceful expiration – Internal intercostals – Abdominals

22 Respiratory Volumes Tidal Volume  each breath. Inspiratory Capacity  biggest inhale Expiratory Reserve  biggest exhale Vital Capacity  maximum volume Residual Volume  air left after exhale VD  anatomical dead space

23 Respiratory Capacities TLC VC IC FRC

24 Spirogram of lung volumes

25 Inhalation and exhalation summary

26 Other factors affecting ventilation Compliance – Elasticity – Surface tension – Thoracic mobility Airway resistance – Airway diameter Contraction and relaxation of smooth muscles ANS input Greatest resistance is in medium bronchi – Obstruction or collapse of airways

27 Gas exchange: Dalton’s Law Dalton’s law—each gas exerts its own pressure – Atm=P N2 +P O2 +P H2O +P CO2 +P other gases Inhaled air – P O2 = 159 mmHg – P CO2 = 0.3 mmHg Alveolar air – P O2 = 105 mmHg – P CO2 = 40 mmHg Exhaled air is a mixture of inhaled and alveolar air

28 Gas exchange: Henry’s Law Henry’s law—the quantity of a gas that will dissolve in a liquid is proportional to the partial pressure of the gas AND the solubility each gas. CO 2 is 20X more soluble than O 2

29 Gas Exchange Partial pressure differences Small distance Molecular weight and solubility of gases Large surface area Coordinated blood- and airflow

30 Ventilation-perfusion coupling Necessary for efficient gas exchange Ventilation  the amount of gas reaching the alveoli Perfusion  blood flow in the capillaries

31 Oxygen transport Red blood cells – Hb + O 2  HbO 2 Hemoglobin saturation and affinity – P O2 of blood – Blood pH – P CO2 of blood – Temperature – Metabolism in RBC’s

32 Hemoglobin and P O2 Oxygen-hemoglobin saturation curve Shape of Hb changes as O 2 binds – Cooperativity Oxygen reserve – Oxygen “bars” Carbon monoxide

33 Hemoglobin and pH Normal blood—pH = 7.4 Active tissues are acidic Bohr Effect  interaction between hemoglobin's affinity for oxygen and its affinity for hydrogen ions

34 Hemaglobin and P CO2 CO 2 + H 2 O  H 2 CO 3  H + + HCO 3 -

35 Hemaglobin and Temperature Normal blood has temperature = 37ºC Active tissues have higher temps

36 Hemaglobin and BPG Biphosphoglycerate (BPG) found in RBCs decreases the affinity of Hb for O 2 Glycolysis produces lactic acid and BPG BPG binds reversibly to Hb and is required for Hb to release O 2

37 Fetal Hemoglobin Higher affinity for O 2 than adult Hb

38 CO 2 Transport Dissolved CO 2 Carbamino compounds – Carbaminohemoglobin Bicarbonate ions – CO 2 + H 2 O  H 2 CO 3  H + + HCO 3 - – Chloride shift Haldane effect

39 Summary

40 Haldane effect O 2 effects on CO 2 transport in blood

41 Nervous Control Respiratory center – Medullary rhythmicity area Ventral respiratory group responsible for pattern generation of breathing – Pontine respiratory group (Pneumotaxic area)

42 Chemical Control PCO 2 PO 2

43

44 Respiratory Reflexes Chemoreceptors – Central – Peripheral Aortic and carotid bodies – Hypercapnia Involuntary hyperventilation – Hypocapnia Voluntary hyperventilation

45 Homeostatic Imbalances Rhinitis Hyperventilation Hyperapnea COPD – Dyspnea – Emphysema – Bronchitis Asthma TB Lung Cancer Cystic Fibrosis

46 Resources Interactive Respiratory Physiology Function of the Respiratory System


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