Personal Injury Anatomy-Cardiovascular System
Personal injury anatomy cardiovascular system is one of several postings dealing with human anatomy and physiology for injury lawyers and plaintiffs. In order to grasp your injury case you must know the basics of anatomy. These postings are designed to provide that. The info in these postings is for the most part from a course offered by The Teaching Company as referenced in the footnotes.
Cardiovascular System-The Heart
The cardiovascular system is the heart and the blood. A human heart pumps 1.3 gallons of blood per minute1. The arteries carry blood away from the heart and veins bring the oxygen depleted blood back to the heart. The heart is in the center of the chest. It is sometimes thought that it’s to the left of center but it is not. That is why when you perform CPR what you are doing is pressing the ribs so that the heart itself can be compressed between the ribs and the back bone. That will cause blood to flow or begin flowing.Call, or contact us for a free consult.
The heart and the lungs are in the thoracic cavity. This cavity is above the abdominal cavity. The diaphragm, which is a sheet of muscle, divides them. The heart is the size of a human fist and weighs about 1 pound. It is a mighty machine in that it pumps blood through 50,000 miles of vessels. These include not only the arteries and veins but also capillaries. To put that into context, the distance around the earth is 24,000 miles.
A human heart consists of four chambers. Two upper chambers are atria or waiting rooms. The two lower ones are ventricles. Blood circulates through the body and returns to the heart into the right upper chamber. From there it then goes into the right ventricle. From there the blood is pumped to the lungs where it is oxygenated. The blood returns to the left upper chamber and it is then pumped into the left ventricle and from there it is pumped throughout the body. Most of the work of the heart is being done on the left side and as such the muscles on the left side are considerably larger than the muscles on the right side2.
Between these chambers there are valves that prevent back flow of blood into the chamber from which the blood came. The valves are like little parachutes which to some extent collapse as the blood is flowing into the lower chamber and, as the chamber below fills up then the parachute billows in order to prevent any back flow into the chamber from which the blood came.
There are coronary arteries that supply blood to the heart itself. When the blood in these arteries ceases to flow then death follows. This is a myocardial infarction or a heart attack. An infarction is simply death of tissue. More than 70% of the blood flow has to be halted before tissue damage becomes a problem.
Although muscle in general may conduct electricity, about 1% of the heart muscle conducts electricity. The nerves also conduct current.
Keeping Track of The Heart
When a doctor places a stethoscope to your chest to listen to your heart, what the doctor hears, at least in part, is the function of the valves. They produce a sound of “lub-dub”. Since there is no air in the heart, the fluid does not splash. The sound of the “lub” is from the closing of the valve leading to the ventricle. The “dub” comes with the closure of two other valves3.
Blood pressure consists of two numbers. The upper number is the systolic pressure. This is the active pressure of the two ventricles pushing blood either to the lungs or out to the body. The diastolic pressure is the lower number which measures the pressure when the ventricles are refilling with blood.
An EKG (electrocardiogram) is a picture of the electrical cycle of the heart.
A common problem with valves are “murmurs”. They arise when a valve is damaged. There are a host of treatments for heart problems. These include stents, placement of balloons into vessels to open them up and bypass surgery which reroutes blood around the damaged area.Call, or contact us for a free consult.
Cardiovascular System-The Blood
Although veins and arteries are the main actors in the circulatory system, the vital work of the exchange of oxygen, carbon dioxide, nutrients and waste occurs at the capillary level. It’s at that level where the exchange occurs of oxygen and nutrients for the carbon dioxide and waste that is brought from the venous side. Every cell in the body is near a capillary because that exchange has to occur at the cell level. That exchange occurs at all of the organs in the body except for the lens and the cornea in the eye which do not have any blood supply. They get their support through diffusion.
The veins in the body are less thick and less mobile than are the arteries. Although blood is pushed through the veins, it is not pushed as hard as the blood that is flowing through the arteries. It is for that reason that if you’re sitting for a long time, you need to be conscious of the blood pooling and clotting in your veins. A clot in the brain is called a stroke. In the lung area it is called a pulmonary embolism. A clot in the leg can be treated. In the lungs it is more of a danger.4.
Blood Is A Mover
The human body has about 1-½ gallons of blood. Blood consists of red cells, white cells and plasma. The red cells contain the oxygen and nutrients. White cells are infection fighters. Plasma is mostly water containing electrolytes, antibodies and clotting agents.
The blood, aside from moving oxygen, picking up nutrients from the GI system and taking away carbon dioxide and other waste also moves hormones.
The blood also maintains balance within the body. All systems within nature prefer balance. This balance in the body consists of balance between acids and bases.Call, or contact us for a free consult.
Heating and Cooling
The blood regulates heat. It can serve as a cooling agent and also serve as a warming agent to warm the vital organs.
During cold weather your hands and feet turn white and shrink. The reason for this is that the blood is going to the center of mass to keep those central organs warm. As such it can be very harmful to take liquor during cold weather. Alcohol is what is called a skin vasodilator which means that it opens the vessels at the skin level. This draws blood from the center of mass which is harmful. It also is a vasoconstrictor, meaning that it restricts the other vessels that carry blood. In cold weather alcohol draws blood away from the center of mass where it is needed.
In hot weather the blood moves towards the skin in order to hasten cooling.
Another part of the blood are platelets which are the clotting compound.
Shock and Angina
Shock is frequent especially after a severe injury. It is a state in which the body cannot maintain enough blood flow. It’s defined as existing where the systolic pressure is less than 80. When a person is in shock the first thing to do is to get IV fluids into the person.
As we get older or engage in actions such as smoking or consuming too much LDL cholesterol, the artery walls become brittle. That may cause white blood cells, a part of the immune system, to respond to fight this. The presence of white cells increases the crowding. This may cause the cholesterol to further build up. This further reduces the blood flow. Coronary artery disease consists of a build up of plaque in the blood vessels. The interior walls of the vessels harden. This is known as atherosclerosis. All of this causes angina which is severe chest pains from a lack of oxygen rich blood in the heart muscle. This also causes congestive heart failure. Such failure is where the heart does not provide enough blood flow to the rest of the body.
Most Strokes Are In Brain
A stroke is also referred to as a cerebrovascular accident. Most strokes are in the brain. However they may be anywhere. A stroke may consist of a bleed from a leaking vessel. It may also be a blockage or clotting within a vessel. Either way there is a loss of oxygen rich blood to the body.
Genetics plays a big role in terms of heart disease. This was seen in basketball great, Pete Maravich. Also running guru, Jim Fixx and tennis legend, Arthur Ashe. Diabetes is also a major player in heart disease. Call, or contact us for a free consult.
1 Understanding the Human Body: An Introduction to Anatomy and Physiology, Anthony A. Goodman, (p. 4).
2 (p. 6).
3 (p. 9).
4 (p. 19).