Flashcards in Chapter 20 Deck (100)
Three parts of the blood vessel wall are?
Tunica interna (endothelium) - inner layer
Tunica media - middle layer
Tunica externa- outer layer
This layer lines the inside of the vessel
This layer is simple squamous epithelium overlying a basement membrane
This layer Is a selectively permeable barrier to materials entering or leaving the bloodstream
This layer is made of smooth muscle, collagen and elastic tissue
This layer strengthens the vessel and changes the diameter of the blood vessel
This layer is made of loose connective tissue
This layer anchors the vessel and provides passage for small nerves, lymphatic vessels and smaller blood vessels
Small blood vessels called vasa vasorum supply blood to the outer wall of larger vessels
These carry blood away from the heart
There are three types of arteries, what are they?
Conducting (elastic or large) arteries
Distributing (muscular or medium) arteries
Resistance (small) arteries
The aorta, pulmonary trunk, Common iliac, common carotid, and subclavian arteries, are what type of arteries?
- These arteries are smaller branches that distribute blood to specific organs
- There Tunica media has layers of smooth muscle allowing vasomotion
- Small arteries, the smallest are arterioles (constriction going on)
- Short vessels that link arterioles and capillaries
- Each forms a pre-capillary sphincter, which is smooth muscle that encircles the entrance to one capillary and can shut off
blood through the capillary bed
A weak point in an artery or in the heart wall is called a?
These exchange vessels, they are called?
There are three types of capillaries, what are they?
Sinusoids (discontinuous capillaries)
- These capillaries are endothelial cells from a continuous tube
- They're found in most tissues
- Small solutes pass-through, but larger particles are held back
- In the brain blood vessel cells are tightly joined in and form the blood brain barrier
- They have pericytes, which are cells with tendrils that wrap around capillaries and regulate permeability, they contribute to
growth and repair
- Cells that have filtration pores
- These pores allow rapid passage of small molecules, but retain larger molecules
- They are found in the kidneys, endocrine glands, small intestine and choroid plexus
- Irregular blood-filled spaces
- Found in the liver, bone marrow and spleen
- Endothelial cells are separated by wide gaps so blood cells and proteins can pass through
- Capillaries are organized into networks called these?
- 10-100 capillaries supplied by single metarteriole
- metarteriole Continues as a thoroughfare channel and leads to a venule
- Capillaries branch off proximal end and empty into the distal end
- When sphincters are closed, blood bypasses the capillaries and flows through the thoroughfare channel to the venule
- These carry blood back to the heart, what are they?
- expand easily to accommodate increased blood volume
- low blood pressure, about 10 mm Hg
There are five types of veins, what are they?
- These are small veins that receive blood from capillaries
- They are porous and also exchange fluid
- These receive blood from postcapillary venules
- Contain one or two layers of smooth muscle
- Infolding of their tunica interna form venous valves
- Valves keep the blood from dropping down with the pool of gravity
- Veins with thin-walls, large lumen and no smooth muscle
- They have smooth muscle in all three tunics
- Venae cavae, pulmonary, internal jugular, and renal veins
The flow of blood back to the heart is achieved by five mechanisms, this process is called?
These Allow blood to flow in only one direction?
There is a venous pressure gradient from venules to the heart favoring the flow of blood to the heart, this is called?
Blood from the head and neck returns to the heart by flowing down through large veins, this is called?
In the limbs, the veins are surrounded by muscles which squeeze the blood out of the vein when the muscles contract, this is called?
Skeletal muscle pump