2.5 Flashcards
What is the cardiovascular system
The cardiovascular system is a connected network of blood vessels, blood and a muscular pump (the heart) It provides tissues with oxygen and nutrients and helps to remove waste and toxins from the body
List functions of the cardiovascular system
Transporting oxygen and removing carbon dioxide
Transporting nutrients and removing wastes
Fighting disease
Transporting hormones
Regulating body temperature
Types of blood vessels
Arteries, Veins, Capillaries
Features of arteries
Arteries carry high pressure blood away from the heart
They have thick, muscular walls with elastic fibres that help them stretch when the heart beats.
The endthelium helps protect the layer of smooth muscle pumping fast moving blood
What does the smooth muscle in arteries do
Contract or relax to control blood flow to an area
What is vasoconstriction
When the artery contracts and the blood flow reduces
What is vasodilation
When the artery relaxes and the blood flow increases
When cold, arteries..
Arteries vasoconstrict in hands, arms, face and legs to keep blood warm in the core of body
When hot, arteries..
Arteries vasodilate in hands, arms, face and legs to use a larger surface area to cool blood down
During intense exercise, arteries in muscles and arms..
Vasodilate
During intense exercise, arteries in digestive system..
Vasoconstrict
During rest, arteries in muscles and arms..
Vasoconstrict
During rest, arteries in digestive system..
Vasodilate
Features of veins
Carry low blood pressure to the heart
Have larger lumen than arteries, but less muscle and elastic fibres
The endothelium is a protective layer lining inside of veins
Purpose of valves
Valves prevent the back flow of blood as venous blood needs to travel from tips of toes to your head.
Features of capillaries
Capillaries are site of exchange of materials between cells and blood
They form a dense network around tissues to increase surface area for exchange
The walls of the capillaries are 1 cell thick to allow for efficient diffusion
Size of lumen in artery
Narrow
Size of lumen in vein
Wide
Size of lumen in capillary
1 cell wide
Wall of vessel in artery
Thick smooth muscle
Wall of vessel in capillary
1 cell thick
Wall of vessel in vein
Thinner smooth muscle
Elasticity of artery
Very elastic
Elasticity of capillary
Not elastic
Elasticity of vein
Slightly elastic
Blood pressure in artery
High
Blood pressure in capillary
Low
Blood pressure in vein
Low
Direction of flow of artery
Away from heart
Direction of flow of capillary
Between arteries and veins
Direction of flow of vein
To heart
What is blood made up of
Plasma
Red blood cells
White blood cells
Platelets
Dissolved substances
Proteins
Amino acids
What is blood plasma
Blood plasma is a yellow watery fluid that carries the other components of blood. It can hold a certain amount of dissolved substances such as carbon dioxide and glucose
What is tissue fluid
Blood reaches the capillary at high pressure, this causes some of the plasma to be pushed through the capillary wall (pressure filtration) into the space next to the cells. When it arrives in this space the fluid is called tissue fluid.
What is pressure filtration
When plasma is pushed through the capillary wall due to blood being high pressure
What does tissue fluid contain
Oxygen, glucose and amino acids that the cells require. These diffuse into the cells that are surrounded by the tissue fluid.
What do tissue fluid and blood plasma both have
Oxygen, carbon dioxide and glucose
What does blood plasma have that tissue fluid doesn’t
Proteins and red blood cells
How does return of tissue fluid work
The tissue fluid that has collected waste and carbon dioxide returns to the blood to get to the lungs, liver and kidneys. Most tissue fluid is reabsorbed by the capillary at the low pressure end.
What happens to tissue fluid that doesn’t return to the capillary
Excess tissue fluid is collected by lymph vessels. As soon as it enters the lymph vessel the tissue fluid is called lymph.
What do lymph vessels do with lymph
Lymph vessels return lymph to the cardiovascular system near the heart
Location of blood plasma
Blood vessels
Location of tissue fluid
Tissue space
Location of lymph fluid
Lymph vessels
