Case Study

By: Kayla Pelishek

Patient with Leukemia since 3 years old

Major Blood Vessels of the Heart

  • Aorta - the largest artery in the body of which most major arteries branch off from.
  • Brachiocephalic Artery - carries oxygenated blood from the aorta to the head, neck and arm regions of the body.
  • Carotid Arteries - supply oxygenated blood to the head and neck regions of the body.
  • Common iliac Arteries - carry oxygenated blood from the abdominal aorta to the legs and feet.
  • Coronary Arteries - carry oxygenated and nutrient filled blood to the heart muscle.
  • Pulmonary Artery - carries de-oxygenated blood from the right ventricle to the lungs.
  • Subclavian Arteries - supply oxygenated blood to the arms.

Heart and Blood

Make up of the Pericardium

Fibrous pericardium and serous pericardium. The serous pericardium is made up of an outer parietal layer that is fused to the fibrous pericardium and an inner visceral layer (aka epicardium) that is a layer of the heart wall and adheres tightly to the heart.


The average heartbeat is 72 times per minute. In the course of one day it beats over 100,000 times. In one year the heart beats almost 38 million times, and by the time you are 70 years old, on average, it's made it to 2.5 billion beats.­

Conduction System of the Heart


- The walls of arteries are much thicker as it carries blood away from the heart at high pressure
- Major arteries close to the heart also have thick layers of smooth muscle in their walls to withstand the increases in pressure as the heart pumps
- The walls also have a large proportion of elastic fibres in both the inner and middle layers – this allows for the arteries to stretch according to the increases in volume of blood. As the heart relaxes the artery walls return to their original position, hence pushing the blood along – maintaining a constant flow in one direction.
- Arteries near the surface of the skin, the changes in the arteries diameter can be felt as a pulse.


- The walls of veins are thinner than the walls of arteries, as the blood they receive from the capillaries is at a much lower pressure.
- The walls have fewer elastic fibres and the lumen is wider (to allow for easier blood flow)
- Veins have two mechanisms for keeping the blood flow constant and in one direction. Firstly many veins are close to muscles, hence when the muscles contract they compress the walls of the vein – pumping blood forwards. Veins also have valves (small pocket like folds of the endothelium lining the lumen of veins), they are spaced along regular intervals in veins. They work much like one-way swinging doors – as the blood is forced through the valve opens, however once the pressure drops and the blood flow decreases, the valve shuts – preventing backflow of blood.


- They are extremely tiny microscopic vessels that bring blood into close contact with the tissues, for the exchange of chemical substances between cells and the bloodstream.
- The one cell thick endothelial layer is a continuation of the lumen arteries and veins
- Diffusion is a relatively slow process and hence the structure of capillaries is suited to slowing down the flow of blood
- In order to maximize the exchange of substances between the blood and cells capillaries have, thin walls (more efficient diffusion) a small lumen (forces blood cells to pass through in single file, slowing down the rate of flow and maximizing their exposed surface area)
- They form an expansive blood flow network, such that no cells are far from blood supply


The electrocardiogram (ECG or EKG) measures heart activity by detecting the electrical activity in the heart. Electrodes attached to the chest, neck, arms, and legs record the pathway of electrical impulses through the heart muscle and record these impulses as tracings on special graph paper. The test is simple and safe, and takes five to ten minutes to perform.

The purpose of the EKG is to detect heart disorders or blockages in the coronary arteries. A normally beating heart produces basically the same pattern of waves in all people.

Variations in this pattern can indicate a number of potential problems: irregular heart rhythms, damage to the heart muscle, enlargement of the heart's chambers, mineral imbalances in the blood. The EKG can also reveal whether the patient has had, or is having, a heart attack.

This test is not foolproof, however, and can produce false results. Some people with normal EKGs have heart trouble, and the graph may show abnormalities where none exists.

EKGs are usually a routine part of a physical checkup after age 40; before that age, patients are recommended to have at least one EKG to use for comparison later.

Blood Pressure

Your systolic pressure (the first and highest number), is the pressure or force the heart places on the walls of your blood vessels as it is working/pumping with each heartbeat.

Diastolic pressure (the second and lowest number) is the lowest pressure the blood places on the walls of your blood vessels when the heart is relaxed between beats.

Both of these measurements are important. A high systolic pressure indicates strain on the blood vessels when the heart is attempting to pump blood into your bloodstream. If your diastolic pressure is high, it means that your blood vessels have little chance to relax between heartbeats.

Normal Blood pressure is 120/80.

5 Factors that Influence Blood Pressure

Nutrition, Alcohol, Exercise, Stress, Smoking

Cardiac Cycle

The cardiac cycle is the sequence of events that occurs when the heart beats. There are two phases of the cardiac cycle. In the diastole phase, the heart ventricles are relaxed and the heart fills with blood. In the systole phase, the ventricles contract and pump blood to the arteries. One cardiac cycle is completed when the heart fills with blood and the blood is pumped out of the heart.

Stroke Volume

The amount of blood pumped by the left ventricle of the heart in one contraction. The stroke volume is not all the blood contained in the left ventricle; normally, only about two-thirds of the blood in the ventricle is expelled with each beat. Together with the heart rate, the stroke volume determines the output of blood by the heart per minute (cardiac output).


The rhythmic dilation of an artery that results from beating of the heart. Pulse is often measured by feeling the arteries.

Normal heart sounds

Normal heart sounds (often called lub-dub) are caused by the pressure changes in the ventricles closing the various heart valves. The first sound, lub, is caused by the closing of the atrioventricular valves after the ventricles have filled with blood and as the ventricles begin to contract. The second sound, dub, is caused by the closing of the semi-lunar valves as the ventricles relax after pushing blood forward.