Componenet 2.23 Adaptations for transport in animals Flashcards
closed circulation system
blood travels through blood vessels with the impetus (momentum) being generated by a muscular pump or heart
open circulation system
the ‘blood’ bathes all the cells and organs of the body.
The blood is called haemolymph and is in the body cavity or haemocoel.
Open circulation is a feature of all arthropods.
There are no red blood cells to transport oxygen; oxygen is delivered directly to the tissues by the tracheae.
Many animals with an open circulation do have a heart that pumps the haemolymph from one area of the haemocoel to another, the blood returns to the heart without the aid of blood vessels.
which is quicker open or closed circulation
Closed circulation systems deliver blood quickly to tissues under pressure. Red blood cells contain haemoglobin which transports oxygen within the circulatory system. The rapidity of transport has enabled the evolution of larger size in animals.
single circulation
blood passes through the heart once in each circulation.
Eg fish
Direction of blood flow in a fish
The heart has two chambers; the atrium, which receives deoxygenated blood from the veins of the body, and the ventricle, which pumps the blood to the gill capillaries via afferent arteries. The blood gains oxygen and flows through efferent arteries to the organs.
do fish have haemoglobin
Their blood contains haemoglobin which has a high affinity for oxygen and transports it from the gills to the tissues.
disadvantages of single circulation
the blood loses pressure around the circuit, resulting in slower circulation.
SINGLE
CLOSED
double circulation
The blood passes through the heart twice in one circulation of the system.
pulmonary circulation + systemic circulation
pulmonary circulation
The right side of the heart pumps blood to the lungs for gas exchange
systemic circulation
The blood returns to the heart and is pumped out to the tissues from the left side
describe including the terms systemic circulation
you can see the deoxygenated blood returning from the systemic circulation of the head and body to the right-hand side of the heart, passing to the lungs on each side, then returning to the left side of the heart to be pumped to the tissues of the head and body.
advantage of double circulation
blood is repressurized when it leaves the gas exchange surface, giving a faster and more efficient circulation to the tissues.
flow of both systemic and pulmonary circulation
Blood moves from the heart to:
Artery → arteriole → capillary → venule → vein →
back to the heart
Arteries take blood Away from the heart.
VeINs take blood INto the heart.
diagram of arterial wall
tunica externa
The outermost tissue layer is the tunica externa which consists of collagen rich connective tissue, this resists stretching of the blood vessel due to the hydrostatic pressure of the blood
tunica media
The middle layer is the tunica media, this contains elastic fibres and muscle tissue. Elastic fibres allow the blood vessel to expand to accommodate the blood flow.
endothelium cells
The innermost layer is a single layer of endothelium cells which provide a smooth surface with little friction and resistance to blood flow. The endothelium is surrounded by the tunica intima.
artery
The heart is a pump that generates pressure, so arteries are adapted to carry blood at high pressure.
They have a thick tunica externa containing collagen fibres, to resist overstretching under pressure.
The layer of muscle and elastic tissue is thick to provide elastic recoil aiding propulsion of blood and maintaining blood pressure.
The lumen of arteries is relatively small to maintain the pressure of the blood.
