Adaptations for transport in animals Flashcards
Describe and explain a open circulatory system:
Blood does not move around the body. It bathes the tissues directly while held in a cavity called the haemocoel. insects have a long dorsal tube-shaped heart, it pumps blood out at a low pressure into the haemocoel.
Describe and explain a closed circulatory system:
single circulation= Blood moves through the heart once in its passage around the body.
double circulation= blood passes through the heart twice in its circuit around the body.
What is the difference between pulmonary circulation and systemic circulation?
Pulmonary= serves the lungs
systemic= serves the body tissues.
Why is double circulation more effective than single?
Oxygenated blood can be pumped around the body at a higher pressure.
Describe the tunica intima:
-Single layer of endothelium
-Smooth lining which helps reduce friction, minimal resistance to blood flow
Describe the tunica media:
-Contains elastic fibres
-In arteries, the elastic fibres allow stretching to accommodate changes in blood flow and pressure
-The contraction of the muscle helps regulate blood flow and maintain blood pressure as it is further from the heart
Describe the tunica externa:
Contains collagen fibres which resist overstretching
Describe what happens at Atrial systole:
Atrium walls contract, the blood pressure in the atrium increases, pushing the blood through the tricuspid and bicuspid valves into the ventricles.
Describe what happens at Ventricular systole:
Ventricle walls contract, increasing blood pressure in the ventricles. This forces blood through the semi-lunar valves.
What happens at the atria during diastole?
Blood from the vena cava and pulmonary veins enters the atria, restarting the cycle.
Describe and explain the thickness in muscle between the atrium and ventricle:
Atrium= have little muscle as it only needs to pump to the ventricle
Ventricle= contain more muscle as it needs to generate enough pressure to send it to the whole body/lungs
