B3.1 Flashcards
Gas Exchange
What is gas exchange?
the exchange of respiratory gases (oxygen, carbon dioxide) between cells/organisms and the environment
How does the exchange of gases between an individual cell and its environment take place?
Through diffusion
Why do large organisms have specialised organs for gas exchange?
because of the surface area to volume ratio that decreases when size increases
What does diffusion require?
a concentration gradient
What are the properties of gas exchange surfaces?
permeability
thin tissue layer
moisture
large surface area
How are concentration gradients maintained?
A dense network of blood vessels
a continuous blood flow
ventilation
What is the thorax?
in mammals, the upper part of the body separated from the abdomen, in insects, the region between head nad abdomen
What is a ventilation system?
a pumping mechanism that moves air in and out of the lungs, maintaining the concentration gradient
What improves the efficiency of diffusion in mammals?
a blood circulation system
a respiratory pigment
What are intercostal muscles?
muscles between the ribs involved in ventilation
What is the diaphragm?
sheet of tissue that separates the thorax from the abdomen in mammals
What are bronchi?
tubes connecting the trachea with the lungs
What is the pleural membrane?
lines lungs and thorax cavity and secretes pleural fluid
What are the alevoli?
air sacs in the lungs
What is surfactant?
substance that lines the inner surface of the alveoli and reduces surface tension
What is a spirometer?
an apparatus that lets you measure the ventilation
What is the tidal volume?
volume of air normally exchanged in breathing
What is the inspiratory reserve?
the difference between the maximum inspiratory level and the tidal volume
What is the expiratory reserve?
The difference between the maximum expiratory level and the tidal volume
What is the vital capacity?
the total amount of air exhaled after maximal inhalation
What is ventilation rate?
number of inhalations per minute
What is the epidermis?
outer layer of leaf cells
What is vascular tissue?
xylem and phloem of plants
What is the vascular bundle?
the site of water and food movement up and down the plant cells
What is the palisade mesophyll?
columnar cells containing many chloroplasts found beneath the upper epidermis in leaves
What is spongy mesophyll?
rounded cells in the lead that are loosely packed creating air spaces where air circulates, provides a large surface area for gas exchange
