Respiratory And Cardiovascular Systems Flashcards
What influences gas exchange ?
SA, diffusion distance, resistance of tissue, large gas partial pressure gradient
Differences between water and air in respiration?
Water is more dense, gills are buoyant in water but collapse in air, partial pressure of o2 variable
What bones protect the gills?
bony operculum or interbranchial septum
What is Ram ventilation?
Swimming forward in water in order to get oxygen, occurs in active fish species
How does respiration work in gills?
V shaped lamellae, counter current exchange
How did the lung evolve?
Early tetrapod > sacs to increase SA, heavily reliant on based diffusion and buccal pumping
Amniotes> complex sacs, one way air flow- not primitive
Mammalia > alveoli, branching into bronchial tree, diaphragmatic ventilatory drive
How do amniotes breath?
Aspiration, mouth is not involved, only active thoracic and diaphragmatic movements, air involved by suction
How do amniotes lungs work?
Elastics, volume expands when inhaled, mammals end in alveoli, reptiles end in faveoli.
How does the human lung work?
Diaphragm in front of liver drives ventilation.
How do reptiles breathe?
Air goes through the trachea into chambers and diffuses into faveoli
Monitor lizards, crocodiles and turtles have chamber subdivided > unidirectional air flow
How is the crocodile breathing highly specialised?
Hepatic piston ventilation- liver drives lung volume changes via the abdominal muscles, similar to birds
How do Avians breathing?
Air moves past lungs into posterior sacs, air moves to lung tissue, wasteair moves to anterior sacs, waste air leaves the body via trachea
What are the major evolution points in ventilation?
Buccal pump- powered by cranial musculature only
Expiration pump- active exhalation powered by axial muscles
aspiration- inhalation powered by axial muscles
What is the Sino-Atrial node?
initiates heartbeat in right atrium
What does the atrio-ventricular node?
Conducts impulse from atria to ventricular
