Anatomy Exam 2 Lecture 7-11

What are the two major elements of the cardiovascular system?

The heart and blood vessels

What is the heart?

The muscular pump that generates the pressure required to move the blood through the body

What are blood vessels?

The distribution tubes of varying diameters

What is the route of circulation?

Heart → Arteries → Arterioles → Capillaries → Venules → Veins → Heart

What do the veins do for the heart?

Bring the blood back to the heart

What do arteries do in terms of the heart?

Bring the blood away from the heart

What is vital to maintain homeostasis?

Blood circulation

Why is the cardiovascular system important?

Because its the body’s internal rapid-transport system for oxygen, nutrients, secretions, and wastes via blood

What is intracellular fluid?

Fluid found inside cells and makes up about 2/3 of the body’s total water

What is extracellular fluid?

Fluid found outside cells; includes blood plasma, interstitial fluid, and lymph

What is blood plasma?

The liquid portion of blood that carries nutrients, hormones, proteins, and waste products and stays inside blood vessels unless filtered out

What is interstital fluid?

Fluid found between and surrounding tissue cells, allows exchange of nutrients, and is formed when substances/water move out of capillaries

What is lymph?

Clear watery fluid that flows through lymphatic system to collect extra fluid/waste from body’s tissues to clean it

What does the lymphatic system do in regards to the cardiovascular system?

Fluid coming out of blood capillaries enters the interstitial fluid (around cells) and is collected by lymphatic vessels to reenter the bloodstream

What can white blood cells do other than attack abnormal cells?

Clean up cellular debris, coordinate tissue repair, remove damaged cells, and regulate inflammation to restore tissue homeostasis

What can happen if blood cells are damaged?

Can change shape and be hard to pass through capillaries, may damage hemoglobin, and can increase blood blood concentration, or worsen circulation, or can just rupture

Why do blood cells have divets?

The biconcave shape of red blood cells maximizes gas exchange efficiency and allows them to move through tiny blood vessels without becoming trapped

What is the myocardium?

Cardiac muscle that make up most of the heart and allows it to function as a durable pump

What is the pericardium?

Tough, fibrous sac that surrounds the heart

What is the enocardium?

The inner lining of the heart, composed of connective tissue and epithelial cells

What is the endothelium?

Epithelial cells that form part of the heart’s inner lining

What is the best benefit of the pericardium?

Acting as a protective barrier against the spread of infections from nearby structures, including the lungs. It also helps anchor the heart in place, prevents excessive stretching when the heart fills with blood, and reduces friction as the heart beats

What is the septum of the heart?

A muscular wall that separates the heart into right and left halves, preventing oxygen-rich and oxygen-poor blood from mixing

What is the right atrium?

The upper chamber of the heart that receives oxygen-poor blood returning to the heart from the body

What is the left atrium?

The upper chamber of the heart that receives oxygen-rich blood returning to the heart from the lungs

What is the right ventricle?

The lower chamber of the heart responsible for pumping blood out of the heart to the lungs

What is the left ventricle?

The lower chamber of the heart responsible for pumping blood out of the heart to the rest of the body

What is the atrioventricular valve?

Valves located between the atria and ventricles that prevent blood from flowing backwards into the atria when the ventricles contract

What are the two types of AV valves?

Tricuspid valve and mitral (bicuspid) valve

What is the tricuspid valve?

The AV valve between the right atrium and right ventricle - it has 3 flaps (cusps)

What is the bicuspid valve?

The AV valve between the left atrium and left ventricle. It has two flaps (cusps).

What is chordae tendinae?

Strong, tendon-like cords that connect the AV valve flaps to papillary muscles attached to the ventricular walls and prevent the valve flaps from flipping backward - blood exists through a semilunar valve

What are semilunar valves?

Valves located where blood exits the ventricles and prevents blood from flowing backward into the ventricles

What are the two types of semilunar valves?

Pulmonary semilunar valve and aortic semilunar valve

What is pulmonary semilunar valve?

Between the right ventricle and pulmonary artery, which carries blood to the lungs

What is the aortic semilunar valve?

Between the left ventricle and aorta, which carries blood to the body

What does the vena cava do?

Large vein that carries oxygen poor blood from the body back to the right atrium of the heart; superior (blood from up to right atrium) and inferior (blood from down to right atrium)

Which side of the heart is better to have damaged?

Right side of the heart because the left side is responsible for sending blood throughout the entire body

What does the cardiac cycle consist of?

(heartbeat) - A sequence of systole (contraction) and diastole (relaxation) of both atria and ventricles

How does blood move through the heart as the atria and ventricles contract and relax?

As the atria fill, the ventricles are relaxed. Pressure of the blood in the atria forces the AV valves open; the ventricles fill as the atria contract. When the ventricles contract, the AV valves close, and blood flows out through the semilunar valves

What is the cardiac output?

The amount of blood each ventricle can pump in a minute; on average the output from each ventricle is about 5 liters

What is the performance of the sound “lub” “dub”?

Lub - Closing of the AV valves and the Dub - Closure of the semilunar valves

What are the events of the cardiac cycle?

Atrial systole, isovolumetric ventricular contraction, ejection, isovolumetric ventricular relaxation, and passive ventricular filling

What is the systolic sound?

first sound, believed to be caused primarily by the contraction of the ventricles and by vibrations of the closing AV valves

What is the diastolic sound?

short, sharp sound; thought to be caused by vibrations of the closing of SL valves

What does the pulmonary circuit do?

Receives blood from tissues, oxygenates blood and removes carbon dioxide through the lungs

What is the pathway of the pulmonary circuit?

Blood from tissues enters the right atrium → tricuspid valve → right ventricle → right semilunar valve → pulmonary arteries → lungs → pulmonary veins → left atrium

What is the pathway of the systemic circuit?

Blood moves from the left atrium → bicuspid valve → left ventricle → left semilunar valve → aorta → body tissues

What is blood pressure?

The force of blood against the vessel walls

What is normal systolic pressure (peak pressure in the aorta)?

120mm of Hg

What is diastolic pressure (lowest pressure in the aorta)?

80mm of Hg

Why is hypertension and hypotension with systolic values?

Hypertension - Blood pressure is too high (stroke/heart attack) (140mm)

Hypotension - Blood pressure too low; loss of water or blood can lead to circulatory shock (<60mm)

What are cappilaries?

The smallest and thinnest tube in the path of circulation and is specialized for exchange of substances with interstitial fluid usually for diffusion

Which structure has better blood resistance?

Capillaries have higher resistance to flowing against the current because there are so many compared to arterioles

What are arterioles?

Small branches of arteries that carry blood toward capillaries - can constrict/dilate

What are venules?

Small blood vessels that collect blood from capillaries towards veins - combined capillaries

What are veins?

Blood vessels that carry blood back toward the heart - combined venules

How does the brain monitor blood pressure?

The brain receives information from specialized receptors in arteries that detect changes in blood pressure. Based on these signals, the brain can adjust heart rate and blood vessel diameter to maintain stable blood pressure

What is vasodilation?

When arterioles relax and widen, decreasing resistance to blood flow and helping lower blood pressure

What is vasoconstriction?

When arterioles contract and narrow, increasing resistance to blood flow and helping raise blood pressure

What is the baroreceptor reflex?

Baroreceptors located in the walls of certain arteries (carotid sinus) to detect changes in blood pressure signaling the brain to adjust heart activity and blood vessel diameter

What is diffusion in regards to the blood?

Substances move from high to low; oxygen and nutrients diffuse from the blood int the interstitial fluid and waste goes into the blood to be destroyed - millions of capillaries surrounds cells so diffusion is good but not good in long distances

What is bulk flow?

Substances pass through pores in capillary walls to exit due to pressure - movement of fluids is important to homeostasis

What is arteriosclerosis?

The hardening and loss of elasticity of artery walls - can increase blood pressure

What is artheroclerosis?

Specific type of arteriosclerosis - Cholesterol and fasts accumulate within artery walls forming plaques which can harden and restrict blood flow (Heart attacks and strokes)

What is LDL and HDL?

Low-Density lipoproteins (Bad) - Carry cholesterol into arterial walls

High-Density lipoproteins (Good) - Remove cholesterol from arterial walls

What is a laser angioplasty & balloon angioplasty?

Laser - Uses a laser to vaporize plaques

Balloon - Small balloons to flatten plaques to open room in the artery - stent keeps area open for surgery

What are statins?

Drugs designed to reduce the amount of cholesterol in the blood

What causes an aneurysm?

Disease, injury, defects that can weaken artery walls and bulge forward due to blood pressure

What is an EEG?

Electrocardiograms (ECGs) are recordings of the cardiac cycle and can be used to reveal irregular heart rhythms

What are arrhythmias, bradycardia, and tachycardia?

Arrhythmias are irregular heart rhythms; bradycardia is a below normal rhythm, while tachycardia is an above normal rhythm

What is ventricular fibrillation?

Occurs when the ventricles contract haphazardly so that blood is not pumped correctly; this can lead to cardiac arrest

How does the heart pump effectively?

A system generating rhythmic impulses and distributing them quickly to the different regions of the myocardium through coordination and precision

What does the conduction system’s structures do?

Highly specialized structures more than ordinary cardiac muscle tissue and permit only rapid conduction of an action potential through the heart

What are the four major structures of the conduction system?

Sinoatrial node (SA node), atrioventricular node (AV node), AV bundle (bundle of His), and the Purkinje system

How does oxygen and deoxygenated blood flow through the heart?

Deoxygenated blood - Body → Vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary arteries → Lungs

Oxygenated blood - Lungs → Pulmonary veins → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta → Body

What does the Sinoatrial node (SA) do?

Known as the heart’s natural pacemaker because of its specialized cardiac cells that spontaneously generate action potentials that initiate each heartbeat that enters the AV node

What does the atrioventricular (AV) node do?

Receives the action potential from the right atrium, delays its transmission to the ventricles to allow the atria to finish contracting and pushing blood into the ventricles then conducts impulse to the Bundle of His which carries it toward the ventricles

What does the Bundle of His (AV bundle) do?

AV bundle receives the action potential from the AV node and conducts it toward the ventricles to the right and left bundle branches which carry the action potential down the interventricular septum

What do the purkinje fibers do?

Rapidly distribute the action potential throughout the ventricular myocardium, causing the ventricles to contract and pump blood into the pulmonary artery and aorta

What is the primary principle of circulation?

Blood flows because of a pressure gradient (P1-P2). The heart creates high pressure, blood travels toward lower-pressure areas, and perfusion pressure ensures tissues receive enough blood to maintain homeostasis

What is the primary determinant of arterial blood pressure?

The volume of blood in the arteries; a direct relationship exists between arterial blood volume and arterial pressure

What is cardiac output (CO)?

Volume of blood pumped out of the heart per unit of time (ml/min or liters/min) determined by stroke volume and heart rate

What is stroke volume (SV)?

Volume pumped per heartbeat. CO (volume/min) = SV (volume/beat) x HR (beats/min) - Fick’s Formula

What determines CO?

Heart rate and stroke volume determine CO and anything that changes the former in the same direction

What is Staling’s Law of the Heart?

Within limits, the more the cardiac muscle fibers are stretched before contraction, the stronger the contraction will be - allows more blood to be pumped

What is End-Diastolic Volume (EDV)?

The amount of blood remaining in a ventricle at the end of diastole (relaxation), just before it contracts determines the amount of stretch placed on the heart fibers

What is the difference between the myocardium and static mechanical pumps?

The myocardium contracts with enough strength to match its pumping load (within certain limits) with each stroke

What also influences contractility?

Chemical factors via the nervous system (norepinephrine) and the endocrine system (epinephrine) and can be triggered by stress and exercise

What factors affect heart rate?

Autonomic nervous system, emotions, exercise, and body temperature

What is peripheral resistance?

The resistance to blood flow imposed by the force of friction between blood and the walls of its vessels - influenced by blood viscosity and diameter of the arterioles

What is blood viscosity and what influences it?

The thickness of blood as a fluid which its subject to change - influenced by high plasma protein concentration, high hematocrit, anemia, hemorrhage, abnormal conditions

How does the diameter of the arterioles influence peripheral resistance?

Vasomotor mechanism - muscles in walls of arteriole may constrict or dilate, changing diameter of arteriole and the small changes in blood vessel due to how many there are

How does resistance influence blood pressure?

When arterioles narrow, less space, blood has more resistance and blood pressure increases but when arterioles widen the blood is able to flow easily and blood pressure decreases or your blood can be thick and can create more friction

What is the vasomotor control mechanism?

Regulates the diameter of blood vessels, especially arterioles, to maintain blood pressure and direct blood toward tissues that need it most

What are the vasomotor control mechanisms?

Vasomotor Pressoreflexes - Respond to blood pressure) Vasomotor Chemoreflexes (Respond to blood chemistry) and Medullary Ischemic Reflex (Emergency Response)

What is the venous return?

Amount of blood returned to the heart by the veins

What is the stress-relaxation effect?

Occurs when a change in blood pressure causes a change in vessel diameter (due to elasticity) and thus adapts to the near pressure to keep blood flowing (works only within certain limits) - pull on gravity decreases venous return

What are venous pumps?

Blood-pumping action of respirations and skeletal muscle contractions facilitate venous return by increasing pressure gradient between peripheral veins and venae cavae

What are the types of venous pumps?

Respirations - Ispiration causes pressure in the chest to decrease while pressure in abdomen increases - helps blood flow toward heart

Skeletal muscle pump - Skeletal muscles contract, squeeze nearby veins, pushes blood toward heart

Venous valves - One-way valves to prevent blood from flowing backward