Anatomy- Circulatory System

Heart chambers

*4 hollow chambers *Upper chambers= atria *Lower chambers= ventricles

Myocardial Infarction

*A blockage of blood flow to the heart muscle. *Heart attack

Major arteries of the systemic system

*Aorta- largest artery of the body - about the size of a garden hose - internal diameter of your thumb

Artery Overview

*Ascending aorta *Aortic arch *Thoracic aorta *abdominal aorta *Brachiocephalic trunk * Common Carotid artery *Subclavian artery *Axillary artery *Brachial artery *Radial artery *Ulnar artery *Common iliac artery *Femoral artery Anterior tibial artery *Fibular artery

Heart Sounds

*Due to vibrations in the heart tissues as blood rapidly changes velocity *Described as a "Lub-Dub" sound *The first sound "Lub" occurs as ventricles relax and semilunar valves close *The second sound "Dub" occurs as ventricles contract and AV valves close

Cardiovascular System

*Has two closed pathways/circuits: 1. Pulmonary 2. Systemic Circuit

What muscle does the heart lay on?

The Myocardium

About how long is the human aorta?

The ascending part of the aorta is approximately two inches long, and the abdominal portion is about six inches long, so the entire aorta is around eight inches.

What is the purpose of the superior and inferior vena cava?

The inferior vena cava is a vein. It carries deoxygenated blood from the lower half of the body to the right atrium of the heart. The corresponding vein that carries deoxygenated blood from the upper half of the body is the superior vena cava.

Why is the left side of the heart more muscular?

The left ventricle has a thicker muscle wall than the right ventricle. This is because the left ventricle has to pump blood all the way around the body, but the right ventricle only has to pump it to the lungs.

Pulmonary valve

The valve is opened by the increased blood pressure of the ventricular systole (contraction of the muscular tissue), pushing blood out of the heart and into the artery. It closes when the pressure drops inside the heart. It is located in the right ventricle of the heart.

Complete heart block

Third-degree atrioventricular block (AV block), also known as complete heart block, is a medical condition in which the impulse generated in the sinoatrial node (SA node) in the atrium of the heart does not propagate to the ventricles.

Heart valves

AV valves *Tricuspid *Mitral (bicuspid) Semilunar valves *Pulmonary *Aortic

Aortic valve

Closes off the lower left chamber that holds the oxygen-rich blood before it is pumped out to the body. Opens to allow blood to leave the heart (from the left ventricle to the aorta and on to the body).

What is the purpose of these valves?

It permits blood to flow one way only, from the left atrium into the left ventricle

T Wave

Repolarization (relaxation) of the ventricles

Into what chamber does blood drain from the vena cava?

Right Atrium

Pulmonary Circuit

Sends deoxygenated blood to lungs to pick up 02 and drop off CO2

Septum

Separates right and left halves so that blood canot mix

Tunica Media

bulky, smooth muscle controlled by the sympathetic nervous system. Helps to dilate or constrict to increase or decrease blood pressure

P wave

depolarization (Contraction) of the atria

QRS Complex

depolarization (contraction) of the ventricles

Bicuspid valve

opens to increased pressure as the left atrium fills with blood. Blood flows through into the left ventricle as the heart expands (diastole). It then closes as the heart contracts (systole) and forces blood into the aorta. This process is vital to the heart's function.

Tunica Interna

thin endothelium, decreases friction

How many seconds are each recorded interval on an ECG?

3 seconds

What does the tricuspid separate? What does the bicuspid separate?

*The tricuspid valve separates the right atrium and right ventricle. It allows blood to flow into the ventricle, but not backwards into the atrium. *The Bicuspid valve separates the left atrium and the left ventricle.

ELECTROCARDIOGRAM (ECG)

*This is a recording of the electrical changes that occur during a cardiac cycle *Each ECG strip lasts 6 seconds *Parts: - P wave -QRS Complex - T wave

Blood Vessel Tunics

*Tunica Interna *Tunica Media *Tunica Externa

What two questions are looked at when evaluating the p wave?

1. Are they present? 2. Do they occur regularly?

Why is the QRS complex bigger than the p wave?

Because of its larger tissue mass

Tachycardia

heart rate that exceeds the normal resting rate

Vascluar system

*Arteries - Away from the heart - feed into: *Arterioles - smaller arteries - feed into: *Capillary beds - drained by: *Venules - which turn into empty: *Veins - carry blood into the heart

Structure of heart

*Hollow *Cone-shaped *Muscular pump *In the Mediastinum *Rests on the diaphragm *Average adult - 14 cm x 9 cm *Base of the heart lies beneath the 2nd rib *The apex sits between the 4th and 5th rib

Blood Pressure

*Measured in mercury *normal blood pressure= 120/80 *The first number represents the pressure when the heart contracts. It is called the systolic blood pressure. *The second number represents the pressure when the heart relaxes. It is called the diastolic blood pressure.

Heart covering and wall

*Outer covering- Pericardium; double layered *Wall of heart (3 layers) 1. Epicardium- connective tissue, reduces friction 2. Myocardium- cardiac muscle 3. Endocardium- Elastic and connective fibers; Connects blood vessels

Where on the human body do the base and apex of the heart lie?

*The apex of the heart is directed downward, forward and to the left. It lies at the level of the fifth intercostals space, about 3.5 inches from the midline. The apex beat can be palpated in the region of apex of the heart. *The base of the heart is the portion of the heart opposite the apex. It is superior and medially located. It forms the upper border of the heart, lies just below the second rib, and primarily involves the left atrium, part of the right atrium, and the proximal portions of the great vessels.

Vessels Overview

*The blood vessels have different thickness due to the differences in pressure that occurs in them or their function with respect to exchanging nutrients with the cells *Arteries have thick walls due to the higher pressure found in them. *The outer layer of the artery is the tunica externa. *The middle layer of the artery, the tunica media, is the thickest layer and it is made of smooth muscle and elastic fibers. *The innermost layer of the artery is the tunica intima and it has a special elastic layer called the lamina elastic internal *The area in the artery where the blood flows is called the lumen. *Veins are thinner walled than arteries and they do not have the same elastic fibers in the tunica media arteries. *Capillaries are different from both arteries and veins in that they are composed of only simple squamous epithelium (endothelium). *The thin nature of capillaries allows them to exchange nutrients, water, carbon dioxide and oxygen with the cells.

Overview of the Cardiovascular System

*The cardiovascular consists of the heart as a pump, blood vessels that take blood away from the heart (arteries) and blood vessels that take blood back to the heart (veins). *The internal jugular vein takes blood to the superior vena cava which takes blood to the heart. *Femoral artery *The femoral vein takes blood to the inferior vena cava before it goes to the heart. *Blood travels to the arm by the brachial artery and deoxygenated blood travels to the lungs in the pulmonary trunk.

Cardiac Conduction system

*The heart contracts by means of electrical signals *The pacemaker of the heart is found in the right atrium and is known as the Sinoatrial (SA) Node

Overview of Circulation

*The heart has 4 chambers including the superior atria and the inferior ventricles. *There are 2 major circulations in the body. One goes to the lungs and is called the pulmonary circulation. *Deoxygenated blood leaves the right ventricle of the heart and travels through the pulmonary artery to the lungs where the blood is oxygenated. *Blood returns from the lungs to the left atrium by way of the pulmonary veins *The other main circulation in the body is called the systemic circulation where blood travels from the left ventricle of the heart and goes to the other regions of the body. *Arteries are vascular tubes that take blood away from the heart while veins are vessels that return blood to the heart. *The first vessel that leaves the heart is the aorta, which is part of the arterial system. Arteries receive blood from the aorta and take blood throughout the body *They branch and become smaller until they become arterioles. The arterioles are the structures that control blood pressure in the body. As they get smaller they become capillaries. *Capillaries are the site of exchange with the cells of the body. They are the interchange between arteries and veins. *On the return flow the capillaries enlarge and turn into venules which take blood to the veins *Blood from the inferior portion of the heart returns to the heart by way of the inferior vena cava.

What are the differences in between these two valves?

*Tricuspid valve- a valve that is situated at the opening of the right atrium of the heart into the right ventricle and that resembles the mitral valve in structure but consists of three triangular membranous flaps—called also right atrioventricular valve.The function of the valve is to prevent back flow of blood into the right atrium. *Bicuspid valve- The mitral valve is one of four valves in the heart. It regulates blood flow from the upper left chamber (left atrium) into the lower left chamber (left ventricle), the heart's main pumping chamber. A normal mitral valve has two flaps, or leaflets.

Heartbeat

*Use stethoscope *Lub Dub sound *The first sound "Lub" occurs as ventricles relax and semilunar valves close *The second sound "Dub" occurs as ventricles contract and AV valves close

Varicose Veins

*Varicose veins, also known as varicoses or varicosities, occur when your veins become enlarged, dilated, and overfilled with blood. Varicose veins are often painful and have a bluish-purple or red color. Often, varicose veins appear swollen and raised. *Varicose veins occur when your vein isn't functioning properly. Veins have one-way valves that prevent blood from flowing backwards. When these valves fail, blood begins to collect in the vein rather than continuing toward your heart. Varicose veins often affect the legs because they are the farthest from the heart and gravity makes it harder for the blood to flow upward. *The primary symptom of varicose veins is highly visible, misshapen veins, usually on the legs. You may also have pain, swelling, heaviness, and aches in the legs. *Your doctor may also want to do an ultrasound to check your blood flow. This is a non-invasive test that uses high-frequency sound waves. It allows your doctor to see how the blood is flowing in your veins. *Your doctor may also want to do an ultrasound to check your blood flow. This is a non-invasive test that uses high-frequency sound waves. It allows your doctor to see how the blood is flowing in your veins. *Other treatment options for varicose veins use lasers or radiofrequency to either remove the veins or seal off blood flow. Such procedures may cause bruising or swelling immediately afterward. But with time, they improve the appearance of the legs. You should always talk to your doctor about your treatment options and the risks before choosing a method.

Cardiac Cycle

1. Atria beat in unison = atrial systole 2. Ventricles contract in unison = ventricular systole 3. Then the entire heart relaxes for a brief moment = diastole *The pressure of the blood on each of the chambers causes the blood to flow from one to the next *Pressure within the heart chambers rise and fall with the contraction and relaxation of the atria *When atria fill, pressure is greater in the atria than the ventricle (forces valves to open) * When ventricles contract, pressure inside them rise sharply causing the AV valves to close and the semilunar valves to open

Blood Flow Steps

1. From the body blood enters through the superior and inferior vena cava 2. It enters into the right atrium 3. Through the tricuspid valve 4 .Into the right ventricle 5. Through the pulmonary valve 6. Into the pulmonary artery 7. Into the lungs 8. Back into the heart via the pulmonary vein 9. Into the left atrium 10. Through the bicuspid valve 11. Into the left ventricle 12. Through the aortic valve 13. Into the aorta 14. Back to the body via the arteries

Contraction of the heart

1. Impulse is generated in the SA Node 2. The impulse then travels to the atrial syncytium (bundle of fibers) which causes both atria to contract together 3.This causes pressure to rise which forces all blood into the ventricles 4. The impulse then travels to the Atrioventricular (AV) Node into the Purkinje Fibers 5. Purkinje Fibers lead into the ventricular syncytium (bundle of fibers) 6. This causes pressure to rapidly increase in the ventricles to close AV valves and contract

Extrasystole

A premature contraction of the heart that is independent of the normal rhythm of the heart and that arises in response to an impulse in some part of the heart other than the normal impulse from the sinoatrial (SA) node. The extrasystole is followed by a pause, as the heart electrical system "resets" itself and the contraction following the pause is usually more forceful than normal. These more forceful contractions are frequently perceived as palpitations.

Arteries Vs. veins

Arteries *Thicker *Tunica media very heavy *Closer to pumping action of heart *Expand as blood is forced into them *Walls are strong and stretchy Veins *Far from the heart *Low pressure *Thin walls *Lumen of vein is much larger *Have valves to prevent backflow *Controlled by skeletal muscle activity

Systemic Circuit

Sends oxygen rich blood to all body cells and removes wastes

Atrioventricular valve (AV valve)

Separates atrium and ventricle to allow blood flow in only one direction *Tricuspid valve *Bicuspid (Mitral) valve

What chamber does the aorta arise from?

The aorta arises from the left ventricle. This blood vessel is the largest artery in the body. The aorta gives rise to other arteries, such as the carotid, coronary and subclavian branches.

What valve separates the atrium and ventricles?

The atrioventricular valves (AV valves), which separate the atria from the ventricles, allow blood to flow from the atria to the ventricles, but prevent flow in the opposite direction. The right AV valves is called the tricuspid valve. The left AV valve is called the mitral valve.

Some people end up with a ventricular septum defect. What is this and why is it a problem?

VSD for short, is a heart condition that can affect teens — although most people with VSDs have had the problem diagnosed long before they reach their teenage years. A VSD is a hole in the wall (called the septum) between the heart's left ventricle and right ventricle. VSDs can range in size from very small to very large. Smaller defects may gradually close on their own.In a person with a VSD, there is an opening in the wall (called the septum) between the right ventricle and the left ventricle. You might hear this type of problem also referred to as a "hole in the heart." As a result, when the heart beats, some of the blood in the left ventricle (which has received oxygen from the lungs already) is able to flow through the hole in the septum into the right ventricle. In the right ventricle, this oxygen-rich blood mixes with the oxygen-poor blood and is directed via the pulmonary artery back to the lungs. The blood flowing through the hole creates an extra noise during the listening exam of the heart, known as a heart murmur. The character of the heart murmur, along with other specific heart sounds that can be detected a cardiologist, may be clues that a person has a VSD.

Ventricular Fibrilation

a heart rhythm problem that occurs when the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in your heart (the ventricles) to quiver uselessly, instead of pumping blood.

Tricuspid valve

a valve that is situated at the opening of the right atrium of the heart into the right ventricle and that resembles the mitral valve in structure but consists of three triangular membranous flaps—called also right atrioventricular valve.

What is the purpose of the chordae tendinae?

cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.