Arteries, Arterioles and Distribution Of Bloof Flow. Flashcards
Tunica intima.
No smooth muscle, elastic tissue.
Tight junctions. important role in the diameter of blood vessel by releasing factors.
What are the three basic layers of a blood vessel?
Tunica intima, Tunica media and Tunica adventitia.
Tunica media.
Circular smooth muscle and elastic tissue.
Smooth muscle innervated by sympathetic nervous system.
Elastic layer.
Tunica adventitia.
Loosely woven connective tissue. Blood vessels, vasa vasorum and protection of these blood vessels.
Which tissue present in an artery are not found in an ateriole?
Elastic and fibrous.
Layers in an artery and arteriole.
Review the organization.
Explain the rise in blood pressure with age.
Arteries stiffen with age, undergo atherosclerosis which leads to a rise in blood pressure.
The pressure in an elastic tube will depend on?
The volume of the fluid,
The distensibility of the walls of the tube.
Blood flow is directly proportional to?
Pressure difference and viscosity.
How to calculate Pulse pressure?
Systolic - Diastolic pressure.
How do you calculate mean arterial pressure?
Diastolic pressure + 1/3 pulse pressure.
Pulse pressure on the graph.
Between highest and lowest points.
What is pulse pressure used to indicate clinically?
Different heart valvular conditions. Aortic stenosis, aortic regurgitation.
What might an impalpable pulse suggest?
Cardiac arrest, Hypovolemia, Peripheral arterial disease (intermittent claudiaction).
Pressure in which arteries are very similar?
Carotid, renal and radial arteries.
Identify sites for the palpation of pulses.
Carotid, brachial, radial, abdominal, femoral, popliteal, anterior amd posterior tibialis and dorsalis pedis pulse.
What changes occur to blood flow from arteries to arterioles?
Decrease in pressure and pulsative to non pulsative.
Cardiac output at rest?
5 L/min.
Cardiac output during exercise?
12.5 L/min.
Equation for flow?
Difference in pressure over Resistance.
Equation for Resistance?
1/Radius to the power 4.
Resistance and flow are both dependant on?
The radius of the blood vessel in question.
Blood viscosity.
Is the measure of internal friction in blood or plasma.
What determines the viscosity of blood?
Packed cell volume or hematocrit.
Polycythemia.
Increase in RBC in response to hypoxia. May cause decrease in perfusion resulting in for e.g. bowel infarction and Raynaud’s phenomenon.
Smooth muscle in arterioles maintain tone which is controlled.
Note.
What are the local and reflex mechanisms for the control of arteriole diameter.
Local - Chemical (oxygen, carbon dioxide, adenosine, other stuff like endothelium factors - NO, local hormones - histamines, prostaglandins), physical and endothelium.
Reflex - Sympathetic (alpha receptors) and Hormonal (alpha and beta receptors).
