Module 3 Section 2 - Blood Vessels Flashcards
What are the 5 types of blood vessels you need to know
Arteries
Arterioles
Capillaries
Venules
Veins
What do the arteries carry
Blood from the heart to the rest of the body
What is said about the structure of the artery
Thick muscular walls
Elastic tissue
Inner lining (endothelium) is folded
Narrow lumen
What type of blood do arteries carry
All carry oxygenated blood with the exception of pulmonary arteries which take deoxygenated blood to the lungs
What is the purpose of the thick and muscular walls and elastic tissue
To stretch and recoil as the heart beats, which helps maintain high pressure
What is the purpose of the endothelium being folded
Allows artery to expand - helps it maintain high pressure
What do arteries branch into
Arterioles
Arterioles are…
Smaller than artieries
What is the structure of an arteriole
Layer of smooth muscle but less elastic tissue
What is the purpose of smooth muscle for Arterioles
The smooth muscle allows them to expand or contract thus controlling the amount of blood flowing to tissues
What do Arterioles branch into
Capillaries
Capillaries are….
The smallest blood vessel
What are examples of substances that get exchanged between cells and capillaries
Glucose and oxygen
Capillaries have been adapted for
Efficient diffusion e.g. their wall are only one cell thick
What do capillaries connect to
Venules
What is the structure of the Venule’s walls
Thin walls that contain some muscle cells
What do Venules join together to form
Veins
What do veins carry
Blood back to the heart
Under what pressure do veins take blood back to the heart
Low pressure
What is the structure of veins
Wider lumen
Very little elastic tissue or muscle tissue
Contains valves
What type of blood do veins carry
All veins carry deoxygenated blood with the exception of pulmonary veins which take oxygenated blood from lungs back to the heart
What is the purpose of the valves
To prevent the back flow of blood
Blood flowing through the veins is helped by what
The contraction of body muscles surrounding them
What surrounds the cells in tissues
Tissue fluid
What is tissue fluid made from
Substance that leave the blood plasma e.g. oxygen, water and nutrients
Cells take in oxygen and nutrients from where
The tissue fluid
Where do cells release metabolic waste
Into the tissue fluid
How do substances move out the capillaries into the tissue fluid in a capillary bed
By pressure filtration
What is the first stage of the formation of tissue fluid by pressure filtration
At the start of the capillary bed, nearest arteries, hydrostatic pressure inside capillaries is greater than the hydrostatic pressure in the tissue fluid. The difference in hydrostatic pressure forces fluid out of the capillaries and into the spaces around the cells
What happens in the second stage of the formation of tissue fluid by pressure filtration
As fluid leaves the hydrostatic pressure reduces in the capillaries - so the hydrostatic pressure is much lower at the end of the capillary bed that’s nearest to the Venules
What happens in the third stage of the formation of tissue fluid by pressure filtration
Another form of pressure is at work called oncotic pressure - this is generate by plasma proteins present in capillaries which lower the water potential. At the venule end of the capillary bed the water potential in the capillaries is lower than water potential in the tissue fluid due to the fluid loss and high oncotic pressure. This means water re enters capillaries from the tissue fluid at the venule end by osmosis
Where does excess fluid drain into
Lymph vessels
What are the smallest lymph vessels called
Lymph capillaries
Where does excess tissue fluid pass into
Lymph vessels, once inside it’s called lymph
What prevents the lymph in lymph vessels from going backwards
Valves
Where is the main lymph vessels located
In the thorax (chest cavity)
Where does the lymph gradually move to
Main lymph vessels in the thorax
When the lymph reaches the main lymph vessels what happens
The lymph is returned to the blood near the heart
Is red blood cells present in blood
Yes
Are white blood cells present in blood
Yes
Are platelets present in blood
Yes
Are proteins present in blood
Yes
Is water present in blood
Yes
Are dissolved solutes present in blood
Yes
Are red blood cells present in tissue fluid
No
Are white blood cells present in tissue fluid
Very few
Are platelets present in tissue fluid
No
Are proteins present in tissue fluid
Very few
Is water present in tissue fluid
Yes
Is dissolved solutes present in tissue fluid
Yes
Are red blood cells found in lymph
No
Are white blood cells found in lymph
Yes
Are platelets found in lymph
No
Are proteins found in lymph
Only antibodies
Is water found in lymph
Yes
Are dissolved solutes found in lymp
Yes
What is meant by dissolved solutes
Salt
What has a higher water potential than blood
Tissue fluid and lymph
When are platelets found in tissue fluid
If the capillaries are damaged
When do most white blood cell enter tissue fluid
When there is an infection
