8.2 Blood vessles Flashcards
what are the five types of blood vessels?
artery
arteriole
vein
venule
capillaries
What and where do arteries and arterioles carry blood?
oxygenated blood from heart to body
what and where do veins and venules carry blood?
deoxygenated blood from the body to the heart?
where do arteries lead?
Arteriole - capillaries - gas exchange occurs
where do capillaries lead into
venules - veins - heart
elastic fibres
these are made of elastin. They stretch and recoil providing the vessel with flexibility
smooth muscle
contracts and relaxes changing the size of the lumen
collagen
provides structural support to maintain the shape and volume of the vessel
is the pressure high or low in Arteries and Arterioles?
High
is the lumen wide or narrow in Arteries and Arterioles?
narrow
are the muscle and elastic layers thick or thin in Arteries and Arterioles?
Thick
how thick is the lumen of the capillary
one blood cell
why is the lumen of the capillary narrow
to ensure blood flows through in single file
how are substances exchanged in the capillaries?
through gaps in the endothelium
do capillaries have a high or low surface are
very high
how is large SA an adaptation of the capillary
allow the diffusion of substances in and out of the capillaries
how is large having a small cross-section area an adaptation of the capillary
it reduces the rate of blood flow from the artery supplying them
how is large having a one-cell thick endothelium an adaptation of the capillary
provide a short diffusion pathway for diffusion
do veins have pulses
no because blood pressure is low
what do vein walls contain
Walls of veins contain a lot of collagen and few elastic fibres and muscle
venules walls
no elastin fibres or smooth muscle
valves
act as a one-way blood flow system to prevent backflow
large valves
these will have active muscles moving
blood
breathing movements
in the chest this aids the movement of blood
systole
blood is pumped through the aorta and other arteries at high pressure. The
elastic fibres of arteries enable them to expand and allow
blood through.
diastole
the blood pressure in the arteries drops. The elastic recoil of the artery walls
help force the blood on.
