Animal Transport Flashcards
vascular system of earthworms
vascularisation, closed circulatory system and
pumps, carriage of respiratory gases in blood
vascular system of insects
open circulatory system, dorsal tube-shaped
heart, lack of respiratory gases in blood
vascular system of fish
single circulatory system
vascular system of mammals
double circulatory system
what is an open circulatory system
Transport medium pumped by the heart is not contained within vessels, but moves freely
Transport fluid comes into direct contact with
the cells
what is a closed circulatory system
● Blood pumped by the heart is contained within blood vessels
● Blood does not come into direct contact with the cells
advantages of closed circulatory system
● Blood pressure can be maintained
● Blood supply to different organs can vary
● Lower volumes of transport fluid required
what is a single circulatory system
● Circulatory system in which the blood travels through the heart once in one circuit
● Blood flows through the heart and is pumped around the body before returning to the heart
what is a double circulatory system
● Circulatory system in which the blood flows through the heart twice in two circuits
● Blood is pumped from the heart to the lungs before returning to the heart. It is then pumped around the
body, after which it returns to the heart again
What are the benefits of a double circulatory
system?
● Maintains blood pressure around the whole body
● Uptake of oxygen is more efficient
● Delivery of oxygen and nutrients is more efficient
● Blood pressure can differ in pulmonary and systemic circuits
Describe the double circulatory system in
humans.
Blood flows through the heart twice in two circuits:
● Pulmonary circuit
● Systemic circuit
Name the four chambers of the mammalian heart.
● Left atrium
● Right atrium
● Left ventricle
● Right ventricle
Describe the pathway of blood around the body, naming the structures of the heart
Pulmonary vein → Left atrium → Left ventricle → Aorta → Body → Vena cava → Right atrium →Right ventricle → Pulmonary artery → Lungs
Where are the atrioventricular valves found and what is their function?
● Found between the atria and ventricles
● Prevent the backflow of blood from the
ventricles into the atria
What are the two types of atrioventricular valves?
● Bicuspid (left side)
● Tricuspid (right side)
Where are the semilunar valves found and what is their function?
● Found between the ventricles and arteries
● Prevent the backflow of blood from the
arteries into the ventricles
Name the five types of blood vessel
● Arteries
● Arterioles
● Capillaries
● Venules
● Veins
Describe the pathway of blood through the blood vessels.
heart → arteries → arterioles →
capillaries → venules → veins → heart
What is the function of arteries?
Carry blood away from the heart to the
tissues, under high pressure.
Relate the structure of arteries to their
function.
Thick, muscular walls to handle high
pressure without tearing. Elastic tissue
allows recoil to prevent pressure surges.
Narrow lumen to maintain pressure.
What is the function of veins?
Carry blood towards the heart under low
pressure.
Relate the structure of veins to their function.
Thin walls due to lower pressure. Require
valves to ensure blood doesn’t flow
backwards. Have less muscular and elastic
tissue as they don’t have to control blood
flow.
What is the function of capillaries?
Form a large network through the tissues
of the body and connect the arterioles to
the venules.
Relate the structure of capillaries to their function
● Walls only one cell thick ∴ short diffusion pathway
● Very narrow, so can permeate tissues and red blood cells can lie flat against the wall, reducing the diffusion distance
● Numerous and highly branched, providing a large surface area
What is the function of arterioles?
Connect the arteries and the capillaries
how many chambers does the heart have
4 chambers
left atrium
right atrium
left ventricle
right ventricle
4 valves
tricuspid valve
bicuspid valve
mitral valve
aortic valve
What is the function of venules?
Connect the capillaries and the veins.
Relate the structure of arterioles and
venules to their function
● Branch off arteries and veins in order to feed blood into capillaries
● Smaller than arteries and veins so that the change in pressure is more gradual as blood flows to the capillaries
What is the cardiac cycle?
● The sequence of events involved in one complete contraction and relaxation of the heart
● Three stages: atrial systole, ventricular systole and diastole
Describe what happens during ventricular diastole.
The heart is relaxed. Blood enters the atria,
increasing the pressure and pushing open the AV valves. This allows blood to flow into the
ventricles. Pressure in the heart is lower than in the arteries, so SL valves remain closed.
Describe what happens during atrial systole.
● The atria contract, pushing any
remaining blood into the ventricles
● AV valves pushed fully open
Describe what happens during
ventricular systole
The ventricles contract. The pressure in the
ventricles increases, closing the AV valves
to prevent backflow and opening the SL
valves. Blood flows into the arteries.
Why is cardiac muscle described as
myogenic?
It initiates its own contraction without
outside stimulation from nervous
impulses.
