Cardiovascular Review

Arteries

Arteries

carry blood away from the heart (systolic and diastolic pressure)

Veins

carry blood towards the heart (diastolic pressure only)

Venules

a very small vein collecting blood from the capillaries

Capillaries

very thin to allow for diffusion of materials into and out of blood

Capillary beds

interweaving network of capillaries that supplies tissue with blood (microcirculation); is fed blood by the terminal arteriole and blood is collected by the postcapillary venule

Arterioles

smallest arteries; directly connected to capillaries

Systole

contraction period of the heart (atrial and ventricular); Atria is squeezing blood to ventricles; ventricle is squeezing blood to aorta

Diastole

relaxation period (atrial and ventricular)

Tunica intima

innermost layer, directly in contact with flowing blood; consists of endothelial cells (continuous with endocardium)

Tunica media

mid layer, made of smooth muscle and elastin, controls vessel diameter and thus blood pressure

Tunica externa

outermost layer, made of connective tissue (collagen) but innervated and connected to lymph vessels

Respiratory pump

the lungs fill up and pump blood from the vessels into the heart; Every time you take a deep breath, the lungs are pressing on the muscles to help move blood

Muscular pump (veins)

the muscles squeeze, squeezing the veins next to it increasing blood pressure; helps the veins’ blood go back to the heart

Baroreceptors

arterial ones function to inform the autonomic nervous system of beat-to-beat changes in blood pressure within the arterial system; a receptor sensitive to changes in pressure

Chemoreceptors

a sensory cell or organ responsive to chemical stimuli

MAP (mean arterial pressure)

the average arterial pressure throughout one cardiac cycle, systole, and diastole. MAP is influenced by cardiac output and systemic vascular resistance, each of which is influenced by several variables

Perfusion

the blood flow at the capillary level in tissue

Pulse pressure

the difference between systolic and diastolic blood pressure

How does the aorta complement the heart in moving blood into body tissues?

The aorta sends out blood from the heart to the rest of the body

What stimulus would cause a pre-capillary sphincter to flex?

When the body is cold, the sphincters will flex to keep blood warmer and prevent it from cooling down by going through capillaries

Veins only have a diastolic pressure. How do veins help to bring blood back to the right atrium?

Valves in the veins, skeletal muscle pumps which put pressure on the veins when the muscles pump which gives it pressure to help blood keep moving, and the respiratory pump which does the same as the skeletal pumps.

What factors influence blood resistance? How can these change over time?

blood viscosity, vessel length and vessel diameter; your blood could become thinner, the longer the vessel, the greater the resistance and the lower the flow, children’s blood vessels increase in length as they grow, diameter of any given vessel may also change frequently throughout the day in response to neural and chemical signals that trigger vasodilation and vasoconstriction

How does blood pressure change with distance as it leaves the left ventricle?

Blood pressure goes down since its getting farther from the aorta which has a high amount of blood. The farther it goes, the less blood will be in one area which decreases the pressure overall. When your heart contracts and aortic valve slams shut, it sends a pressure wave but it weakens as you go farther from it, dissipating the force

How is vasoconstriction and vasodilation controlled?

sympathetic nervous system and/or chemical stimulation flexes the muscle in the tunica media causing vessels to constrict to retain heat or increase bp (vasoconstriction) or decrease bp and allow heat loss (vasodilation)

Why does blood acidity (acidosis) affect heart (and breathing) rate?

As blood pH drops, the parts of the brain that regulate breathing are stimulated to produce faster and deeper breathing. Breathing faster and deeper increases the amount of carbon dioxide exhaled, which raises the blood pH back toward normal

Why would a prolonged drop in blood pressure make you feel thirsty?

Drinking more water would increase the blood pressure because the more water in the system, the more pressure there is in the blood

Blood flow in capillaries is very slow compared to arteries and veins. Why is this beneficial?

It allows for the cells to be able to take all the nutrients from the blood and gives time for diffusion.

How can blood pressure be influenced by blood chemistry? (ADH, adrenaline, histamines, etc.)

The hormones can increase or decrease water retention which affects pressure. They can also increase blood flow and heart rate as well as dilating or constricting blood vessels.

What conditions would stimulate angiogenesis, and why is it necessary under such conditions?

Reduced blood flow to tissue (ischemia) or reduced oxygen to tissue (hypoxia). It’s necessary because if the tissue continues to undergo ischemia and hypoxia, it will eventually die if angiogenesis doesn’t occur.

How is blood pressure information sent to the brain?

Baroreceptors sense change in pressure of the blood and send signals to the brain to either dilate or constrict the vessels

What parts of the brain control blood pressure?

medulla oblongata is essential for signal transmission between the spinal cord and upper brain regions and for managing autonomic functions including heart rate and breathing

Why is it beneficial to breathe out hard when straining during heavy exercise?

if you don't breathe, the lungs stay inflated and blood doesn't go back to the heart ;If you breathe out hard, it releases the CO2 that was created by the body due to the O2 being used to supply the muscles with it and give them energy to continue lifting. This prevents a build up of CO2 in the blood.

What is an aneurism? What causes an aneurism to happen?

bulge in a blood vessel caused by a weakness in the blood vessel wall, usually where it branches; High blood pressure can place increased pressure on the walls of the blood vessels and weaken them over time, atherosclerosis results in the weakening of vessels

interpret the chart

As the blood gets farther from the heart, the bp decreases. Two lines because systolic in arteries is really strong and separates from diastolic but it weakens in the veins. When your heart contracts and aortic valve slams shut, it sends a pressure wave but it weakens as you go farther from it, dissipating the force

venous return is dependent on

respiratory pump, skeletal muscle pump, and valves

cardiac output

the amount of blood pumped out by the ventricles in a minute

stroke volume

amount of blood pumped out of each ventricle during each contraction

stroke volume factors

preload, afterload, contractility

preload

the degree to which cardiac muscle cells are stretched before they contract; this is determined by venous return; the force that stretches the cardiac muscle prior to contraction

venous return

the amount of blood extending the ventricles prior to contraction

contractility

the contractile strength of a muscle at a certain length; increased contractility results in lower ESV

afterload

the arterial pressure that must be overcome for the ventricles to eject blood; pressure required by the heart ventricles to "open the door" of the aortic and pulmonary valves due to blood pressure; the amount of pressure that the heart needs to exert to eject the blood during ventricular contraction