The Structure & Function Of Arteries, Capillaries And Veins Flashcards
(15 cards)
What is the cardiovascular/circulatory system composed of?
Blood, blood vessels and the heart
What does the heart function as?
A pump to move blood through the blood vessels of the body
What five functions does the circulatory system provide that are essential for multi cellular organisms and necessary for life?
Transporting oxygen and removing CO2
Transporting nutrients and removing wastes
Fighting disease
Transporting hormones
Regulating body temperature
How does blood travel in the circulatory system?
It travels around the body through arteries to the capillaries and then veins which return the deoxygenated blood to the heart
What happens to blood pressure in the circulatory system?
It decreases the further away from the heart it travels, it’s always lower in veins compared to arteries
What is the composition of blood?(in mammals)
Red blood cells
White blood cells
Plasma
What are the three main blood vessels?
Arteries
Veins
Capillaries
What is each blood vessel composed of?
Central lumen
Thin layer of epithelial cells called Endothelium(lines lumen)
Layers of tissues(nature depends on blood vessel)(surrounds endothelium)
What is arteries structure?
Arteries have an outer layer of connective tissue containing elastic fibres and a middle layer contains smooth muscle with more elastic fibres
The elastic walls of the arteries stretch and recoil to accommodate the surge of blood after each contraction of the heart
Blood flow through the artery is a high pressure
The smooth muscle allows vasoconstriction and vasodilation to control blood flow
Vasoconstriction and vasodilation in the arteries what does it control?
How is it brought about?
Vasoconstriction and vasodilation controls the blood flow
This action is brought about by the contraction(causing vasoconstriction) or relaxation(causing vasodilation) of the smooth muscle in the arteries
What is the structure of veins?
They have an outer layer of connective tissue containing elastic fibres and a much thinner muscular wall than arteries
Valves are present to ensure the blood flows in one direction and prevents back flow
What do capillaries allow?
What’s their structure?
They allow the exchange of materials /substances with tissues through their thin walls
They are composed of epithelial cells that are one cell thick to allow easy diffusion of substances
What is the difference between veins arteries and capillaries?
Veins- carry LOW pressure blood back to the heart (veIN), wider lumen, thinner muscular wall, valves prevent back flow of blood
Arteries- carry HIGH pressure blood AWAY from the heart (Artery), narrow lumen, thick muscular walls
Capillaries- thin walls(one epithelial cell thick) to allow glucose and oxygen to easily pass through, connect arteries and veins
What happens during pressure filtration?
Blood arrives at the capillary from the artery at a higher pressure compared to the blood in the capillaries.
This causes plasma to pass/be forced through capillary walls into the tissue fluid surrounding the cells
Tissue fluid supplies cells with glucose, oxygen and other substances
Carbon dioxide and other metabolic wastes diffuse out of the cells and into the tissue fluid to be excreted
Much of the tissue fluid returns to the blood
Lymphatic vessels absorb the excess tissue fluid and return as lymph to the circulatory system
Compare tissue fluid and blood plasma
Tissue fluid and blood plasma are similar in composition
However, blood plasma contains plasma proteins which are too large to be filtered through the capillary walls
