Cardiovascular System Lecture Notes

A set of vocabulary flashcards based on the cardiovascular system, focusing on key concepts and definitions related to blood vessels, blood pressure, and related physiological mechanisms.

Blood Vessels

The tubular structures carrying blood through the circulatory system.

Tunica Intima

The innermost layer of blood vessels, containing endothelial cells.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood toward the heart.

Capillaries

Small blood vessels where gas and nutrient exchange occurs.

Mean Arterial Pressure (MAP)

The average pressure in a person's arteries during one cardiac cycle.

Preload

The degree of stretch of the heart muscle before contraction.

Afterload

The resistance that the heart must overcome to eject blood.

Baroreceptor Reflex

A reflex mechanism by which blood pressure is regulated. Heart rate, contractility, and blood vessel diameter is controlled through it from parasympathetic and sympathetic fibers

Vasoconstriction

The narrowing of blood vessels, which increases blood pressure.

Vasodilation

The widening of blood vessels, which decreases blood pressure.

Hydrostatic Pressure

The outward force of the capillaries caused by blood pressure

Osmotic Pressure

Inward force during capillary exchange caused by proteins that are stuck in the caillaries

Edema

Swelling caused by excess fluid trapped in body tissues.

Tunica media

Middle layer of the veins and arteries

Tunica externa

The outermost layer of blood vessels, consisting of connective tissue that provides strength and elasticity.

vasa vasorum

Small blood vessels that supply the walls of large blood vessels.

Where are vasa vasorum found and what is its importance.

Vasa Vasorum supply nutrients to the outer walls of blood vessels where blood might not be able to reach.

What structure is found in arteries that isn’t found in veins?

Elastic lamina

Why is elastic lamina found only in arteries?

Arteries contain most of the pressure and is also the most varied pressure so it needs the flexibility.

Elastic arteries

More elastin fibers, found in areas of varied blood pressure and large amount of pressure,

Helps maintain blood pressure and helps with the change

Arterioles/Resistance arteries

Small arteries. They regulate blood flow and resistance, playing a crucial role in controlling blood pressure.

Thin layers of tunica

Muscular arteries

Vasoconstriction and vasodilation. These arteries have a thick muscular layer that allows them to regulate blood flow and pressure through contraction and relaxation.

Explain vasoconstriction and how it occurs

Shrinkage of blood vessels that increase blood pressure by reducing flow. Sympathetic nerves input create cardioaccelerator reflex

Explain vasodilation

Opens up blood vessels reducing blood pressure and increasing blood flow. no sympathetic inputs. Parasympathetic fibers from the vagus nerve determine this

What does the body do to blood flow during vigorous activity?

It will decrease blood flow from other parts of the body such as the gi tract and increase it on the skeletal muscle

Why is tunica intima made of endothelium?

The tunica intima is made of endothelium to provide a smooth surface for blood flow, reduce friction, and facilitate absorption and secretion. Mostly secretion

Explain capillaries

structures made of tunica media, they are permeable with openings and slits formed from incomplete tight junctions. They also contain precapillary sphincters.

Fenestrated capillaries

Capillaries have holes poked in them

Sinusoidal capillaries

Capillaries that have large openings like sinuses. Commonly found in the liver for large molecules

Precapillary sphincters

Made of smooth muscle and found only in the arteries to block or open pathways when we are at rest or exercising.

Venous valves

Found in veins. Prevents backflow

Capacitance vessels

Veins that can stretch to accommodate varying volumes of blood, allowing them to act as reservoirs.

Why is most of the blood contained in the veins?

Veins have low pressure so when damaged you won’t lose all of it very quickly compared to if an artery was damaged.

Explain systolic blood pressure

Maximum pressure achieved in the arteries during the heart ejection

Explain diastolic blood pressure

lowest pressure in the arteries during ventricular diastole or relaxation

Explain how you find pulse and pulse pressure (pp)

PP= SBP-DBP

Mean arterial pressure (MAP) equation

MAP=DBP+1/3PP

MAP= HR x SV x TPR = CO x TPR

Venous pressure

pressure in the vena cava or pressure in the right atria

What structures have a pulse?

Arteries have a pulse as they have large amounts of blood pressure

Stroke volume =

End diastolic volume - End systolic volume

Cardiac output =

Heart rate x stroke volume

Amount of blood ejected per minute

explain how a blockage of a vein or artery increases blood pressure

The structure will be constricted, constriction reduces blood flow and increases pressure

How does an increased heart rate reduce stroke volume?

The heart will spend less time in it’s diastolic phase which decreases the amount of blood filling the ventricles.

End diastolic volume

The volume of blood in the ventricles at the end of diastole, just before the heart contracts. When EDV increases Stroke Volume increases

End systolic volume

The volume of blood in the ventricles at the end of systole, after the heart has contracted.

Explain the Frank-Sterling law

The Frank-Starling law states that the heart's stroke volume increases in response to an increase in the volume of blood filling the ventricles (end diastolic volume), due to the elastic properties of cardiac muscle. The more the heart is filled during Diastole the more that will be pumped into the Aorta

What is preload?

Ventricular stretch determined by the EDV or the volume of blood returning to the heart, which influences cardiac output by affecting stroke volume.

What is afterload?

The pressure that the ventricles must overcome to eject blood during systole, which affects stroke volume and cardiac output.

What influences SV

End diastolic volume. If diastolic volume is large, or large amounts of blood, stroke volume will increase with it.

Explain an increase or decrease in afterload on stroke volume

An increase allows the heart to eject less blood making less volume of blood ejected will a decrease will make it easier to eject blood therefor increasing the volume ejected.

Parasympathetic innervation of the heart

Relaxation mode found in the SA and AV nodes. SA and AV nodes innervate the rest of the heart and determine its movement so the rest of the heart doesn’t need them

Sympathetic innervation of blood vessels

SA and AV nodes + Ventricular myocardium. These have sympathetic innervations in order to keep the heart contracted and increase heart rate, enhancing blood flow and pressure.

Where else are sympathetic innervations found?

Blood vessels and the adrenal medulla

Carotid baroreceptors

Specialized sensory receptors located in the carotid arteries that detect changes in blood pressure and help regulate cardiovascular responses. vagus and glossopharyngeal nerves innervate here

Aortic baroreceptors

Sensory receptors located in the aortic arch that monitor blood pressure and assist in regulating cardiovascular function. vagus and glossopharyngeal nerves innervate here

What innervations do the baroreceptors have from what nerves system

The baroreceptors are innervated by the sympathetic and parasympathetic nervous systems, primarily through the glossopharyngeal (IX) and vagus (X) nerves, facilitating regulation of blood pressure.

What is the importance of the hypothalamus and the Abdulla oblongata in the heart?

The hypothalamus plays a crucial role in regulating autonomic functions such as heart rate and blood pressure, while the medulla oblongata, specifically its cardiovascular center, regulates vital functions including heart rhythm and blood vessel diameter.

What innervations slow down the heart?

parasympathetic fibers

what innervations speed up the heart and the contractility

sympathetic fibers

Less preload means what?

less diastolic filling of the heart which decreases cardiac output

A decrease in blood pressure would do what? Think of blood loss or a traumatic accident

inhibit parasympathetic fibers and begin to use sympathetic fibers. Blood vessels would constrict creating more preload and increased heart rate and cardiac output.

Vasodilation occurs how?

removal of all sympathetic input

Vasoconstriction occurs how?

through sympathetic stimulation causing blood vessels to narrow.

What are the three forms of transportation in the capillaries?

Diffusion, Osmosis (osmotic pressure), Filtration(hydrostatic pressure)

Why is movement at the arteriolar end of the capillary greater than at the venule end

Blood pressure creates the gradient and because the venule end has almost no pressure that is why it is greater at the arterial end

What can happen to the pressures if you have reduced plasma content in the blood?

Reduced levels of proteins will decrease osmotic pressure which means less fluid into the capillaries which means edema.

How do baroreceptors bring down the blood pressure?

Signals the AV and SV nodes via parasympathetic fibers to reduce heart rate

Inhibits the sympathetic fibers

Control center for the baroreceptors

Hypothalamus and medulla oblongata

BP =

CO x TPR

What determines SV

Preload, contractility, afterload

What factors influence blood pressure

blood viscosity

Cardiac output

Stroke volume

Heart rate

Blood volume

Peripheral resistance