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gills

alveoli. Gas Exchange Respiratory Systems. elephant seals. gills. food. O 2. ATP. CO 2. Why do we need a respiratory system?. Need O 2 in for aerobic cellular respiration make ATP Need CO 2 out waste product from Krebs cycle. Gas exchange.

josephine-taylor
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gills

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  1. alveoli Gas Exchange Respiratory Systems elephantseals gills

  2. food O2 ATP CO2 Why do we need a respiratory system? • Need O2 in • for aerobic cellular respiration • make ATP • Need CO2 out • waste product fromKrebs cycle

  3. Gas exchange • O2 & CO2 exchange between environment & cells • need moist membrane • need high surface area

  4. Optimizing gas exchange • Why high surface area? • maximizing rate of gas exchange • CO2 & O2 move across cell membrane by diffusion • rate of diffusion proportional to surface area • Why moist membranes? • moisture maintains cell membrane structure • gases diffuse only dissolved in water

  5. Thoracic Cavity • 3Divisions: - Right and left pleural division - Mediastinum • Parietal pleura lines the entire thoracic cavity and each lung is encased in a separate pleural sac (visceral pleura) • Pleurisy • Thoracic capacity expands and contracts in combination with diaphragm contracting (increase) and relaxing (decrease) to allow for inspiration and expiration

  6. Respiratory System • 3 Divisions: • Upper respiratory tract nose, pharynx (nasopharynx, oropharynx, laryngopharynx), and larynx 2. Lower Respiratory tract trachea, bronchial tree, lungs 3. Accessory Structures oral cavity, ribcage, respiratory muscles

  7. Lungs Exchange tissue:spongy texture, honeycombed with moist epithelium

  8. Alveoli • Gas exchange across thin epithelium of millions of alveoli • total surface area in humans ~100 m2

  9. Negative pressure breathing • Breathing due to changing pressures in lungs • air flows from higher pressure to lower pressure • pulling air instead of pushing it

  10. Mechanics of breathing • Air enters nostrils • filtered by hairs, warmed & humidified • sampled for odors • Pharynx  glottis  larynx (vocal cords)  trachea (windpipe)  bronchi  bronchioles  air sacs (alveoli) • Epithelial lining covered by cilia & thin film of mucus • mucus traps dust, pollen, particulates • beating cilia move mucus upward to pharynx, where it is swallowed

  11. Pulmonary Volumes • Measured with a spirometer • TV (tidal volume) • ERV (expiratory reserve volume) • RV (residual volume) • IRV (inspirational volume) • Vital Capacity = IRV + TV + ERV

  12. Autonomic breathing control • Medulla sets rhythm & pons moderates it • coordinate respiratory, cardiovascular systems & metabolic demands • Nerve sensors in walls of aorta & carotid arteries in neck detect O2 & CO2 in blood

  13. Medulla monitors blood • Monitors CO2 level of blood • measures pH of blood & cerebrospinal fluid bathing brain • CO2 + H2O  H2CO3 (carbonic acid) • if pH decreases then increase depth & rate of breathing & excess CO2 is eliminated in exhaled air

  14. Hemoglobin • Why use a carrier molecule? • O2 not soluble enough in H2O for animal needs • blood alone could not provide enough O2 to animal cells • hemoglobin in vertebrates = iron (reddish) that absorbs oxygen heme group cooperativity

  15. Respiratory Disorders Inflammation, Infection, and Anatomical URI: • Rhinitis • Pharyngitis • Laryngitis

  16. Respiratory Disorders • Deviated Septum • Epistaxis LRI: • Acute Bronchitis • Tuberculosis • Lung Cancer

  17. Respiratory Function Disorders • General group of disorders that cause decreased lung volumes and capacities Obstructive Pulmonary disorders • Chronic Obstructive Pulmonary Disease (COPD) • Emphysema • Asthma

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