Test 4: Blood Vessels and Hemodynamics Flashcards
What is arterial pathway starting with the heart?
Heart > Arteries> arterioles> capillaries (site of exchange between circulatory system and tissues)
What side of the heart pumps blood through 60,000 miles of blood vessel?
The left side
What side of the heart sends blood to the lungs to drop off CO2 and pick up O2?
The right side
What type of vessels carry blood away from the heart?
Arteries
What are the three layers of the Tunica interna (tunica intimate)
Endothelium, basement membrane, internal elastic lamina (internal elastic membrane)
What is the endothelium?
The innermost layer of vessels that is in direct contact with blood
What is made of simple squamous endothelium that contributes to vessel permeability?
Endothelium
What is deep to the endothelium and is made of collagen fibers that anchors the endothelium to other layers?
The basement membrane
What is the boundary between the tunica interna (tunica intimate) and the Tunica media?
Internal elastic lamina (internal elastic membrane)
What is made of a thin sheet of elastic fibers with Swiss cheese like openings that facilitate diffusion?
Internal elastic lamina
What is the largest layer in most vessels?
Tunica media
What are the two layers of the tunic media?
Smooth muscle layers and external elastic lamina (external elastic membrane)
What is the layer that varies the most among different vessels and are thicker in arteries?
Tunica media
What controls the size of the vessel diameter under sympathetic control
Smooth muscle layers
What effect does sympathetic stimulation have on blood vessels?
It causes vasoconstriction and blood pressure to rise
What happens when sympathetic stimulation of a blood vessel stops?
The vessel relaxes and begins to dilate and return to normal size
What are three vasodilators that can be found in the bloodstream?
Nitric oxide, hydrogen, and lactic acid
What layer is made of elastic fibers which separate the tunica media and the tunica externa?
External elastic lamina (membrane)
What is the outer layer of a vessel?
Tunica externa
What is the Tunica externa made of?
Elastic and collagen fibers that allow passage of nerves and tiny vessels along the outside of the vessel
What are vessels that supply the three layers of larger vessels?
Vasa Vasorum (vessels to vessels)
What layer helps to anchor vessels to surrounding tissue?
Tunica externa
What is compliance?
And artery’s ability to stretch to accommodate the force of the heart
What are the three types of arteries?
Elastic, muscular, arterioles
What are the largest types of arteries, (found in aorta, pulmonary trunk, branches of arch)?
Elastic arteries
What are the properties of elastic arteries?
Well defined internal and external elastic lamina, and thick tunica media
What is the function of elastic arteries?
To force blood into smaller vessels
What are the medium sized arteries (femoral, axillary, brachial, radial, ulnar, splenic)?
Muscular arteries
What are the properties of muscular arteries?
75% smooth muscle with 40 layers
What are muscular arteries also known as?
Distributing arteries, because they distribute blood to the organs
Why is the smooth muscle of muscular arteries always under slight partial contraction?
To maintain blood pressure
What are arterioles?
Small arteries that carry blood to capillary beds
What are Metarterioles?
The tapered end of an arteriole that leads into a capillary bed
What is resistance?
Opposition to blood flow created by the friction of formed elements on the vessel wall
Why does the Tunica externa have an extensive sympathetic nerve supply?
To control the size of the arteriole and as a result control blood flow into the capillary bed
What is the ability of the muscle to contract in order to keep a constant state of partial contraction?
Vascular tone
Do muscular arteries stretch, and recoil as elastic arteries do?
No
What is an anastomosis?
A union of two vessels that do not form a capillary bed, in order to create collateral circulation.