Mass Transport In Animals 3.3.4.1 Flashcards
What are the reactants constantly needed provided for metabolism?
Oxygen and Glucose
Why can single celled organisms gain oxygen and glucose directly from their surroundings?
Due to their short diffusion distance, molecules can diffuse to all parts of the cell quickly
Why cannot larger organisms use diffusion?
Larger organisms have multiple layers of cells and so diffusion paths are greater
What solves the problem of larger organisms not being able to use just diffusion?
A mass transport system
What is a mass transport system?
Bulk movement of gases or liquids in one direction via a system of vessels or tubes
What is the difference between a closed circulatory system and an open circulatory system?
Closed
Blood is pumped around the body and always contained within a network of blood vessels
Open
Blood is not contained within blood vessels and blood is pumped directly into body cavities
What is a double closed circulatory system?
In one complete circuit of the body, blood passes through the heart twice
What is the pulmonary and systemic circulatory system?
Pulmonary circulatory system
Right side of the heart pumps deoxygenated blood to lungs for fas exchange
Systemic circulatory system
Blood returns to left side of the heart so oxygenated blood can be pumped around the body
What is the coronary arteries function?
To supply the cardiac muscle cells with nutrients and remove waste products
What is the sound the heart makes and what are they caused by?
S1 - Lub - Closing of the AV valves
S2 - Dub - Closing of the SL valves
What happens in atrial systole?
Walls of atria contact so atrial volume decreases and pressure increases which force the AV valves open. This pushes blood into the ventricle which causes a slight increase in ventricular pressure
What is ventricular systole?
Walls of ventricle contract so ventricular volume decreases and pressure increases which forces the AV valves to close (preventing backflow). Ventricular rises above pressure in arteries which force SL valves open and blood through.
What is cardiac diastole?
Ventricles and atria are both relaxed and ventricular pressure drops below artery pressure so SL valves close. Atria fills with blood again
Advantage and disadvantage of a double circulatory system
Disadvantage
High pressure needed to pump blood around the body
Advantage
Lower pressure needed in lung capillaries for gas exchange
What is the septum?
Divides left and right side of the heart
