Blood Vessles Flashcards
Can you describe the function of the blood?
Transports and carries oxygen and nutrients
Carries waste products to the liver for purification
Carries away CO2, urea
Participates in hormonal regulation
Regulates Temp and pressure
Can you name how many walls are the arteries and the veins are lined with and can you state their name and what type of tissue they are.
Tunica Intima - Endothelium
Tunica Media - Smooth Muscle
Tunica Externa - Connective Tissue
What is the Lumen?
The Lumen is basically the canal by which the blood passes in, think of it like an underground tunnel where travel inside of it.
Can you name the 3 types of arteries and how are they different from each other?
The 3 types of arteries are:
- Muscular Artery: Contains the highest amount of smooth muscle and have a smaller lumen. They are distal to the elastic arteries and supply groups of organs. Have an internal and external elastic membrane forming an inner and outer layer of the tunica media
- Elastic Artery: Contains the highest amount of Elastic Tissues and the largest lumen. They are the largest arteries near the heart.
- Arteriole: Is the smallest type of artery with very little smooth muscle and elastic tissues and has the smallest lumen. Contain one or 2 layers of smooth muscle cells, larger arterioles have all 3 tunics.
What is an angioplasty and can you describe the the process?
Angioplasty is a procedure used to open a coronary artery by expanding the artery itself.
Angioplasty is a minimally invasive surgery where the wrist is numbed and a guide wire is inserted inside the radial artery and is then moved towards the aorta of the heart.
After reaching the aorta, a catheter wrapping the guide wire is inserted and the guide wire is removed,
After the catheter reaching the aorta, the catheter secretes a dye that is used to pinpoint the location of the blockage.
After locating the blockage, a balloon is sent to the blocked site and expands the artery, increasing blood flow.
The balloon is then removed and a stent will be placed in place of the balloon.
What are aneurysms?
An aneurysm is a bulge or ballooning in the wall of an artery. If an aneurysm grows large it can burst and cause dangerous bleeding or even death
What are arteries and can you name 3 superficial arteries?
Arteries are blood vessels that carry oxygenated blood around the body and are high in pressure to deliver the oxygenated blood around the body,
What is vasodilation and vasoconstriction? And what controls these actions?
Vasoconstriction is the contracting of the smooth muscle which constricts the blood vessel tightening the lumen. Vasodilation is the relaxation of the smooth muscle, allowing the vessel to dilate and might increase the lumens size.
What are 2 ways that control the diameters of the arterioles?
1) Local factors in the tissues signal the smooth muscle cells to contract or relax, thus regulating the amount of blood sent.
2) sympathetic nervous system adjusts the diameter of arterioles throughout the body to regulate systemic blood pressure.
How do the capillaries contribute to the body?
Capillaries are small in diameter and only have 1 layer of endothelial cells making them so thin that molecules and nutrients are able to pass through the membrane and into the interstitial fluid, which all body cells interact with in order to exchange gases, acquire nutrients and remove waste products,
Capillaries also haver site-specific functions, an example would be the lungs, where the oxygen enters the blood through capillaries and CO2 leaves through them.
What are capillary beds and describe how they are connected. Please describe in detail how they work using important keywords.
Capillary beds are interconnected networks of the smallest blood vessels. They are supplies by the terminal arteriole and exits through the postcapillary venule. The terminal arteriole leads to the metarteriole, which is the vessel between the arteriole and capillary, from which branch TRUE capillaries.
The metarteriole continues through the thoroughfare channel which is the vessel between the capillaries and the postcapillary venule. The true capillaries join at the thoroughfare channel which then join the postcapillary venule.
The flow of blood across the true capillaries is controlled by smooth muscles called the precapillary sphincters, regulating blood supply according to the tissues need of oxygen.
If the tissue is active, the precapillary sphincters relax, allowing the blood to flow through the true capillaries. If the tissue is not active or is not in need of oxygen, the precapillary sphincters contract shutting of the true capillary vessels, thus traveling from arteriole to venule directly.
PS: For clear diagram, please seek Marieb Human Anatomy 6th edition, page 584.
How do the capillaries maintain permeability and block the movement of molecules and allow it at the same time?
The capillaries are made of a thin lining of endothelial cells which contain tight junctions and intercellular clefts. These 2 control the permeability of capillaries by blocking and allowing exchange of molecules. As the name suggests, a tight junction is the part of the capillary structure that prevents any movement of molecules while the intercellular cleft allows the movement of molecules.
What are the 2 types of capillaries in the body and how are they different in structure and function?
The 2 types of capillaries are fenestrated capillaries and continuous capillaries and they are different as the fenestrated capillaries have fenestrations (pores) spanning the entire endothelial cell layer allowing for more movement and exchange of molecules.
Continuous capillaries are more common than fenestrated capillaries and don’t have the fenestrations along their endothelial cell layer,
What are the 4 routes by which molecules pass through?
(1) by direct diffusion through the endothelial cell membranes; (2) through the intercellular clefts; (3) through pinocytotic vesicles that invaginate from the plasma membrane and migrate across the endothelial cell; and (4) through the fenestrations in fenestrated capillaries.
How is the blood-brain barrier different from other capillaries in terms of structure and function?
The blood brain barrier prevents everything but VITAL molecules from passing through it and moving inside the brain. These capillaries are CONTINUOUS capillaries lacking ANY intercellular clefts. The vital molecules pass through this highly selective membrane by complex mechanisms.
This barrier does NOT block lipid soluble molecules such as carbon dioxide and oxygen.
