BVB301 Lecture Notes - Lecture 5: Bronchus, Air Sacs, Bronchiole
Document Summary
Small animals: rely solely on diffusion (no need for bulk airflow) Large animals use: bulk flow of water/air (sponges, insects, diffusion -> gas transport (worms, leeches, ventilation -> gas transport (vertebrates) Allow exchange of o2 and co2 between lung air spaces and blood. Carry o2 in the blood from the lungs to the tissues and brings co2 back to the lungs for removal from the body. Functions of the respiratory system: gas exchange (o2 and co2, thermoregulation, ph balance, vocalisation, olfaction, humidification and warming of inhaled air, water loss, protection of respiratory surfaces. Structure: upper tract, nostrils (nares, nasal passages. Supported by cartilage rings (prevents collapsible: bifurcates at the level of heart. Smaller than trachea but similar: primary bronchi: extrapulmonary. Alveoli: air sacs that make up lung tissue. Spontaneous discharges from the medulla (brain stem: autonomic: some voluntary control possible, controlled by higher cns input and vagal feedback from the lungs, pneumotaxic and apneustic centres (pons)
