Blood transport functions and heart chamber structure

Cardiovascular System

Functions of the Cardiovascular System

Food substances, transported by the blood, include: amino acids, fatty acids, mineral salts and vitamins from a person's intestines to the cells of his/her body.

Waste substances, transported by the blood, for produced by cells during their normal metabolism. The primary ones include carbon dioxide, water and urea. The blood transports these waste substances from an individual/s cells to his/her excretory organs.

Heat, produced in the liver and muscles, is transported by the blood to all areas of an individual's body. This constitutes a person's central heating system, which helps keep his/her 37 degrees C.

Hormones, from an individual's endocrine glands, are transported by the blood to his/her target cells.

Oxygen it's transported by the red blood cells from an individual longs to his/her other body cells. (Wright, 2000, p. 38)

Figure 1: Depiction of How Blood Transports Substances around a Person's Body (Wright, 2000, p. 39)

2. The major parts of the heart, divided into 4 parts known as chambers, include: on the right side of the heart, the right atrium and the right ventricle: on the left side of the heart, the left atrium and the left ventricle. The right atrium and the left atrium are the two small chambers at the top of the heart, while the right ventricle and the left ventricle are the two larger chambers at the bottom of the heart. The left ventricle constitutes the primary pumping chamber. The right and left side of the heart divided by a "wall," known as the septum. The left side of the heart pumps oxygen-rich blood to the body. The following figure (2) portrays the major parts of a human heart. (Major Parts, 2008; the Heart, N.d.)

Figure 2: Major Parts of a Normal Heart (Major Parts, 2008)

Serous membranes, covering membranes, line body cavities not open to the exterior of the body and are found around the heart and lungs. "The outer layer is called the parietal layer and is always attached to the surrounding tissues. The inner layer is called the visceral layer and is firmly attached to the organ it covers." The pericardium surrounds the heart. (Serous Membrane, N.d.)

Endocardium

The endocardium, a single layer of endothelial cells with oval or round nuclei rests on a continuous layer of fine college and fibers, separated from it by a thin basement membrane. Just beyond the subendonthelial layer, a paper layer of dense connective tissue exists that forms the majority of endocardium. Along with collagen fibers, "the subendocardial layer contains elastic fibers, smooth muscle cells, small blood vesssels, and in the ventricles, may contain specialized cardiac muscles of the electrical conducting system. The connective tissue of the subendocardial layer binds the endocardium to the cardiac muscle of the myocardium. (Krause, 2004, p. 37)

Myocardium

The myocardium, which primarily consists of cardiac muscle cells, is thickest in the left ventricle in thin is in the atria. The fine connective tissue which envelops each cardiac muscle cell of the ventricular myocardium contains numerous capillaries. "In the atria, bundles of cardiac muscle are prominent adjacent to the lumen and form the pectinate muscles. Isolated bundles of cardiac muscle that project into the lumen of the ventricles form the trabeculae camea. In the atria, cardiac muscle cells are smaller than elsewhere in the heart. Elastic fibers are scarce in the ventricular by Accordion but are plentiful in the atria where they form and interlacing network between cardiac muscle cells. Here the elastic fibers of the myocardium become continuous with those of the endocardium and epicardium." (Krause, 2004, p. 37)

Epicardium

The epicardium is the visceral layer of the pier epicardium. The free surface is covered by a single layer of flat to cuboidal mesothelial cells, beneath which is a layer of connective tissue reach in elastic fibers. Adjacent to the myocardium, it contains blood vessels, nerves and an abundance of fat cells. This reason is referred to as the subepicardial layer." (Krause, 2004, p. 37)

3. Pathway of Blood through the Heart

The following figure (3) shows the passage of blood through the heart. The human heart, which consists of two pumps, beats approximately 100,000 times and pumps approximately 5,000 gallons of blood each day. At rest, a normal human heart beats between 60 and 80 beats a minute.

The left side of the heart, stronger as it has more work to perform, receives fresh oxygenated blood from the lungs and pumps it around the body. The right side of the heart, which receives de-oxygenated blood from the body, pumps it to the lungs. As the lungs are located close to the heart perform less work, consequently the right side of the heart is weaker than the left side. (the Heart, N.d.)

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Figure 3: Passage of Blood through the Heart (the Heart, N.d.) blood pressure (include the terms systolic and diastolic).Identify the normal range of arterial blood pressure.

Use terms: hypertension, hypotension, normotension correctly.

5.Generalised Plan of Blood Vessels

Locate the major arteries and veins and including:

Arteries:aorta, coronary, left and right subclavian, brachiocephalic, right and left common carotid, vertebral, axillary, brachial, radial:

Abdominal aorta, gastric, splenic, celiac, hepatic, renal, esenteric, L&R common iliac, femoral, tibial.

9. Conducting system of the Heart

The following figure portrays the pathway of the cardiac conduction system and identifiues: the sino atrial (SA) node, atrial conducting fibres, the atrioventricular (AV) node, the atrio ventricular bundle (Bundle of His) L&R bundle branches and Purkinje fibres.

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Figure 4: Cardiac Conduction System (Cardiac Conduction, 1996)

10. Parts of a normal electrocardiogram pattern

Identify the P, QRS and T. waves on an ECG.

Identify which part of the cardiac cycle occurs during P, QRS and T. waves.

11.Cardiac Cycle

The following figures (5 & 6) portray atrial systole, ventricular systole and diastole, tachycardia, bradycardia.

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Figure 5: Cardiac Cycle (Cardiac Cycle, 2006)

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Figure 6: The Cardiac Cycle (Cohen, 2005)

CARDIAC CYCLE

Although the right and left halves of the heart are separate, they both contract in unison, producing a single heartbeat. The sequence of events from the beginning of one heartbeat to the beginning of the next is called the cardiac cycle. The cardiac cycle has two phases: diastole, when the heart's chambers are relaxed, and systole, when the chambers contract to move blood. During the systolic phase, the atria contract first, followed by contraction of the ventricles. This sequential contraction ensures efficient movement of blood from atria to ventricles and then into the arteries. If the atria and ventricles contracted simultaneously, the heart would not be able to move as much blood with each beat.

During diastole, both atria and ventricles are relaxed, and the atrioventricular valves are open. Blood pours from the veins into the atria, and from there into the ventricles. In fact, most of the blood that enters the ventricles simply pours in during diastole. Systole then begins as the atria contract to complete the filling of the ventricles. Next, the ventricles contract, forcing blood out through the semilunar valves and into the arteries, and the atrioventricular valves close to prevent blood from flowing back into the atria. As pressure rises in the arteries, the semilunar valves snap shut to prevent blood from flowing back into the ventricles. Diastole then begins again as the heart muscle relaxes -- the atria first, followed by the ventricles -- and blood begins to pour into the heart once more.

An instrument known as a stethoscope is used to detect internal body sounds, including the sounds produced by the heart as it is beating. The characteristic heartbeat sounds are made by the valves in the heart not by the contraction of the heart muscle itself. The sound comes from the leaflets of the valves slapping together. The closing of the atrioventricular valves, just before the ventricles contract, makes the first heart sound. The second heart sound is made when the semilunar valves snap closed. The first heart sound is generally longer and lower than the second, producing a heartbeat that sounds like lub-dup, lub-dup, lub-dup.

Blood pressure, the pressure exerted on the walls of blood vessels by the flowing blood, also varies during different phases of the cardiac cycle. Blood pressure in the arteries is higher during systole, when the ventricles are contracting, and lower during diastole, as the blood ejected during systole moves into the body's capillaries. Blood pressure is measured in millimeters (mm) of mercury using a sphygmomanometer, an instrument that consists of a pressure recording device and an inflatable cuff that is usually placed around the upper arm. Normal blood pressure in an adult is about 120 mm of mercury during systole, and about 80 mm of mercury during diastole. Blood pressure is usually noted as a ratio of systolic pressure to diastolic pressure for example, 120/80. A person's blood pressure may increase for a short time during moments of stress or strong emotions. However, a prolonged or constant elevation of blood pressure, a condition known as hypertension, can increase a person's risk for heart attack, stroke, heart and kidney failure, and other health problems. (Cardiac Cycle, 2006)

State what is meant by stroke volume, heart rate and cardiac output.

12. Relationship of Cardiac Output to Stroke Volume and Heart Rate

13. Clinical Investigations of the Heart

State what is meant by:

Electrocardiogram

Angiogram

Auscultation

14. Blood a) What are the three main functions of blood?

A b) What percentage of blood is plasma?

Plasma is a pale yellow mixture of water, proteins and salts."

Plasma, which is 90% water, makes up 55% of blood volume." (56 Facts About Blood, 2005) c) What is the function of plasma?

What is Blood Plasma? Plasma is the liquid component of Blood, in which the Blood cells are suspended. Serum is the same as Blood plasma except that clotting factors have been removed. Plasma is translucent with a faint straw color, similar to the color of this web page. It is mainly composed of water, Blood proteins, and inorganic electrolytes. Plasma serves as a transport medium for glucose, Blood borne lipids, hormones, metabolic end products, carbon dioxide and oxygen. Plasma is the storage and transport medium of clotting factors and the protein content that is necessary to maintain the pressure of the Blood circulatory system. (Sell Plasma, 2006) d) the main constituents of plasma include 90% water: 10% dissolved substances.

A e) Solid formed elements of blood include f) the different types of white blood cells consist of Phagocytes, and Lymphocytes. Lymphocytes include B. lymphocytes and T. lymphocytes.

A g) Haemoglobin (also spelled hemoglobin), approximately 95% of the dry weight in red blood cells is responsible for oxygen transport? ("haemoglobin," 2006) h) Blood type O constitutes the universal blood donor type.

A i) Describe the chain of events responsible for haemostasis.

A j) Discuss the functions of blood under the following:

Transport; regulation and protection

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Figure 7: Composition of Blood (Wright, 2000, p. 37)

4. Measurement of Blood Pressure k) Anaemia constitutes a condition which occurs when an individual's body possesses an abnormally low amount of red blood cells or not enough haemoglobin. (Anaemia, 2007; Wright, 2000, p. 37) l) the most common cause/form of anaemia is often a shortage of iron in an individual's diet. A diet with red meat and green leafy vegetables, tomatoes, capsicums etc., is commonly recommended to those who have anaemia as.

A m) Two other causes of anaemia include "inadequate absorption of vitamin B12 from the diet [which]... can be due to ulcers, stomach cancer, diseases of the small intestine or from the after effects of surgery," and lack of folic acid due to a poor diet and if a person drinks excessive alcohol. (Anaemia, 2007) n) Outline the 3 major steps of blood clotting.

The following figure (8) depicts how blood clots are formed, "by a series of complex reactions requiring the presence of 13 clotting factors, including calcium."

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Figure 8: How Blood Clots are Formed (Wright, 2000, p. 37) o) Differences between a, B, AB and O. blood groups.

Under the ABO Blood typing (grouping) scheme, there are two especially important antigens called a and B. Every living human has either one or both or neither of the red Blood cells. An individual with Blood group a is so because he has antigen a. Antigen B. makes a person's Blood group B. If a person has both antigens, then they are in group AB. If they have neither, the Blood group is O." (BLOOD TYPES and COMPATIBILITY, 2005) p) Rh positive and Rh negative.

Antigens, proteins on the surface of blood cells, can trigger a response from the immune system. The Rh factor constitutes a type of protein on the surface of red blood cells. Most people with the Rh factor are Rh-positive. Those who do not have the Rh factor, on the other hand, are Rh-negative...."More than 85% of people are Rh positive."(Rh Factor, 2008) q) the general term used to describe an inherited blood clotting disorder is haemophilias. (Kay, 1972/1998) r) What are plaque deposits on the walls of blood vessels mainly composed of?

A s) Why can polycthaemia potentially cause a heart problem?

Rh Factor. (2008). http://www.americanpregnancy.org/pregnancycomplications/rhfactor.html

Red blood cells contain haemoglobin, a red pigment which gives blood its colour. The job of haemoglobin is to carry oxygen around the body. When red blood cells and therefore haemoglobin are low the blood fails to supply the body's tissues with sufficient amounts of oxygen. As your lungs and heart will then have to work harder to get oxygen into the blood, symptoms of anaemia, such as difficulty in breathing will begin to develop. (Anaemia, 2007) visceral pericardium) parietal pericardium and fibrous pericardium.