Sistem Pernafasan.

Presentasi berjudul: "Sistem Pernafasan."— Transcript presentasi:

1 Sistem Pernafasan

2 Lingkup bahasan Structure and function of the respiratory pumps How gasses are exchanged with blood The role of pressures and surfactants in rate of exchange How respiration is regulated

3 Respiratory System: Overview
Figure 17-2 b: Anatomy Summary

4 Paru: permukaan untuk pertukaran gas
Luas: 75 m2; berdinding tipis dan lembab Dilindungi oleh tulang iga (costae), otot dan kulit Diafrgama dan tulang iga berperan sebagai pompa

5 Fungsi sistem pernafasan
Pertukaran Oksigen (O2) dari udara ke darah dari darah ke sel Pertukaran CO2 dari sel ke darah dari darah ke udara Pengendalian pH darah Pembentukan suara Melindungi alveoli Figure 17-1: Overview of external and cellular respiration

6 Aliran udara dari luar hingga alveoli
Udara disaring, dihangatkan dan lembab Melalui hidung (mulut), trachea, bronchi dan bronchiolus Luas permukaan yang dilalui semakin sangat besar Figure 17-4: Branching of the airways

7 Sifat fisika gas Gas dimampatkan; peningkatan tahanan akan menurunkan kekuatan arus Udara merupakan campuran gas; setiap gas dapat berdifusi secara independen

8 Pleura: double membrane
Ventilation: The Pumps Inspiration Expiration Diaphragm Low energy pump Concavity – flattens Thorax: ribs & muscles Pleura: double membrane Vacuum seal Fluid-lubrication

9 Respiratory Damage & Diseases
Pneumothorax ("collapsed lung") Fibrotic Lung Disease Emphysema Asthma

10 Factors Affecting Ventilation
Airway Resistance Diameter Mucous blockage Bronchoconstriction Bronchodilation Alveolar compliance Surfactants Surface tension Alveolar elasticity Figure 17-2e: Anatomy Summary

11 Lung Volumes: Spirometer Measurements

12 Efficiency of Breathing: Normal & High Demand
Total Pulmonary Ventilation (rate X tidal vol about 6 L/min) Alveolar ventilation (– dead air space – 4.5 L/min) Little variation [O2] & [CO2] Exercise- High Demand  Depth of breathing Use inspiratory reserve

13 Gas exchange in the alveoli
Figure 17-2 g: Anatomy Summary

14 Gas exchange in the alveoli
Thin cells: exchange Surfactant cells Elastic fibers Recoil Push air out Thin basement membrane Capillaries cover 90% of surface

15 Matching Ventilation with Alveolar Blood Flow (Perfusion)
Mostly local regulation Low [O2] in alveoli  vasoconstriction of arteriole Reduced blood flow at rest (lung apex ) saves energy High blood [CO2]  bronchodilation

16 Summary Diaphragm & rib cage are pumps for inspiration
Alveolar surface exchanges O2 & CO2 with blood The gasses in air act independently & move down a pressure gradient Airway resistance can limit ventilation efficiency Typically ventilation matches blood perfusion via local regulators of vasodilation & bronchodilation

17 Summary of Oxygen Transport

18 Gas Transport in the Blood: Carbon Dioxide
Excess CO2 in blood (Hypercapnia) Leading to: acidosis, CNS depression & coma 7% in plasma, 23% bound to Hb & 70% as HCO3- acts as a buffer [H+]

19 Gas Transport in the Blood: Carbon Dioxide
Figure 18-13: Carbon dioxide transport in the blood

20 Regulation of Ventilation: Central pattern generator
Integrates input from cortex, limbic & chemoreceptors Rhythmic contractions of ventilation

21 Regulation of Ventilation: Central pattern generator
Figure 18-15: Reflex control of ventilation

22 Regulation of Ventilation: Pons Center
Dorsal respiratory group – inspiration Ventral respiratory group – forced breathing

23 Regulation of Ventilation: Chemoreceptors
Carotid & aortic bodies: O2, CO2 & H+ receptors Medullary CO2 receptor Low [O2], high [CO2] & low [H+]  ventilation

24 Regulation of Ventilation: Chemoreceptors

25 Summary of Regulatory Ventilation Reflexes

26 Protective Reflexes Bronchoconstriction Irritant receptors Toxic particles Irritating particles (i.e. pollen) Hering-Breuer Reflex prevents over inflation Unconscious reflexes take over voluntary breathing

27 Summary Oxygen is transported bound to Hb and this is affected by temperature, pH, CO2 Carbon dioxide is transported in plasma, bound to Hb and acts as the buffer bicarbonate Respiration is regulated by CNS central pattern generator, pons center and peripheral carotid and aortic receptors Feedback reflexes coordinate circulation and ventilation to maintain blood O2, CO2, and H+ concentrations