Exam 3 Flashcards
What are the 3 shunts in fetal circulation
Ductus venous - found at the liver and the umbilical vein that helps shunt oxygenated blood to the inferior vena cava
Foremen ovale - found in the wall between the right and left atrium that allows oxygenated blood from right atrium to flow into left atrium
Ductus arteriosus - found connecting the pulmonary artery and the aorta it helps shunt mixed blood away from the lungs instead going directly into the aorta
What is the structure of an artery
Tunica intima
-Endothelium
-Internal elastic membrane
Tunica media
-Smooth muscle
-Elastic connective tissue
Tunica externa
-connective tissue
-vasa vasorum
What is the structure of a vein ?
Tunic intima
-endothelium
-internal elastic membrane (only in very large veins)
Tunica media
-smooth muscle
(Smaller than arteries)
Tunica externa
-connective tissue (collagen fibers)
-Vasa vasorum
Describe arterial blood pressure ? What do the top and bottom numbers mean ? What are the sounds you hear and what do they represent ?
Arterial blood pressure is the force that is exerted by the blood on the arterial wall
The top number is the systolic blood pressure the bottom number is the diastolic blood pressure
The sounds you hear are called the korotkoff sounds and they are generated when a blood pressure cuff changes the flow of blood through the artery
Describe fast/short term neural control of cv system
the parasympathetic nervous system releases ACh reducing the excitability of the SA node this results in lower blood pressure
The sympathetic nervous system releases NE which acts on SA node to increase heart rate , on cardiac myocytes to increase stroke volume and on vascular smooth muscle to cause vasoconstriction this all increases blood pressure
describe the factors that affect peripheral resistance and give clinical examples
Diameter
-The sympathetic nervous system can cause your blood vessels to constrict decreasing diameter increasing resistance
Length
- People who are obese have longer blood vessels causing there heart to beat faster to keep the same amount of pressure in the vessel increasing resistance
Viscosity
-A person has polycythemia which causes there blood to be really thick making it harder to move through vessels
Explain the importance of venous valves, the muscular pump and the respiratory pump
Venous vales are one way valves that only allow for upward movement of blood this is to counter act the affect of gravity and aid in venous return
The muscular pump is when skeletal muscle contracts and compresses the vein that lies in between them, this causes a local increase of pressure which opens the valves towards the heart and the blood in that segment is pumped up. when the muscle relaxes the vein expands and pressure drops while the lower valve opens and blood is pulled up from the lower segment
The respiratory pump happens when you breath and the diaphragm contracts this increases pressure in the abdomen and decreases pressure in the thoracic area this causes a pressure gradience and more blood is pulled up increasing venous return
describe some age related changes to the cardiovascular system ?
-Blood vessels stiffen up as arteries become less elastic
-Heart rate decreases
-Heart muscle stiffens, heart pumps less efficiently
-Heart enlarges slightly
-Baroreceptors become less sensitive
-Heart can not accommodate to meet increased need as blood flow to skeletal muscle and vital organs decrease
-Veins return less blood
-Blood pressure may increase
What is an aneurysm ? and what risk do they pose
an abnormal bulge or ballooning in the wall of a blood vessel
An aneurysm can burst this is called a rupture a ruptured aneurysm causes bleeding inside the body and often leads to death
what is vasoconstriction and vasodilation and give examples when they would happen
Vasoconstriction is the process of blood vessels getting smaller to restrict the blood flow to certain muscles
-During cold exposure your body triggers vasoconstriction to reduce blood flow to the skin helping to conserve body heat
Vasodilation Is the process of your blood vessels dilate to get bigger to allow more blood to get to muscles
-During exercise your vessels will dilate to allow more blood to get to muscles
what is angiogenesis
Angiogenesis is the process of new capillaries forming out of preexisting blood vessels in your body
What is pulse pressure
Pulse pressure is the difference between your upper (systolic) and lower (diastolic) numbers in your blood pressure reading
what is vasomotion
the Intermittent flow due to constriction - relaxation cycles of precapillary sphincters or arteriolar smooth muscle
what is mean arterial blood pressure ? and how do you calculate it
MAP is the average arterial pressure during a cardiac cycle
MAP = 2(DBP) + SBP / 3
What is a cerebrovascular incident
A CVA also known as a stroke is what happens when the brain lacks oxygen usually due to a clot in the blood vessels which cuts off oxygen supply to the brain and the tissue begins to die
