Exam Questions Flashcards
Explain why oxygen is not released until the blood reaches the capillaries
-arteries have thick wall
-no diffusion happens until capillaries
Explain why blood off loads more oxygen to respiring tissues than to resting tissues
-high levels of CO2 produced
-lower affinity of haemoglobin for oxygen
Name 2 types of epithelial tissue
- ciliated
- squamous
Explain how the alveoli create a surface for efficient gaseous exchange
- wall is one cell think for short diffusion
- elastic so recoil air and helps with ventilation
- large number of alveoli = large SA
- small surface of alveoli = large SA:V
- cells secrete surfactant to maintain SA
Explain the term tidal volume
-volume of air inhaled or exhaled in one breath
Explain the meaning of vital capacity
-the maximum volume of air inhaled or exhaled in one breath
Explain the significance of the relationship between rate of diffusion and the SA:V for large plants
-have low SA:V
-diffusion is too slow to supply requirements
How does squamous epithelium improve efficiency of gas exchange?
-shorter diffusion path
Explain why a delay between the excitation of the atria and excitation of the ventricles
-allow time for the atria to fully contract
-allows blood to move
-so ventricles don’t contract too early
Explain why the excitation wave from the septum is carried to the apex
-so that ventricular contraction starts at apex/base
-to push blood upwards
-efficient emptying of ventricles
Suggest why it is not possible to expel all the air from the lungs
-lungs cannot be completely compressed
-trachea are held open by cartilage
-bronchioles held open by elastic fibres
How would you carry out a dissection to display maximum detail of a gas exchange system?
-remove operculum
-display gills
