blood structure and function pdf

Blood Structure And Function Pdf

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Blood is a combination of plasma and cells that circulate through the entire body.

Find GPs in Australia. The formed elements are so named because they are enclosed in a plasma membrane and have a definite structure and shape. All formed elements are cells except for the platelets, which are tiny fragments of bone marrow cells.

How does blood work, and what problems occur?

Identify the primary functions of blood, its fluid and cellular components, and its characteristics. Recall that blood is a connective tissue. Like all connective tissues, it is made up of cellular elements and an extracellular matrix. The cellular elements—referred to as the formed elements —include red blood cells RBCs , white blood cells WBCs , and cell fragments called platelets.

The extracellular matrix, called plasma , makes blood unique among connective tissues because it is fluid. This fluid, which is mostly water, suspends the formed elements and enables them to circulate throughout the body within the cardiovascular system. The primary function of blood is to deliver oxygen and nutrients to, and remove wastes from, the body cells; but that is only the beginning of the story.

The specific functions of blood also include defense, distribution of heat, and maintenance of homeostasis. Nutrients from the foods you eat are absorbed in the digestive tract. Most of these travel in the bloodstream directly to the liver, where they are processed and released back into the bloodstream for delivery to body cells. Oxygen from the air you breathe diffuses into the blood, which moves from the lungs to the heart, which then pumps it to the rest of the body.

Moreover, endocrine glands scattered throughout the body release hormones into the bloodstream, which carries them to distant target cells. Blood also picks up cellular wastes and byproducts, and transports them to various organs for removal. For instance, blood moves carbon dioxide to the lungs for exhalation from the body, and various waste products are transported to the kidneys and liver for excretion from the body in the form of urine or bile. Many types of WBCs protect the body from external threats, such as disease-causing bacteria that have entered the bloodstream in a wound.

Other WBCs seek out and destroy internal threats, such as cells with mutated DNA that could multiply to become cancerous, or body cells infected with viruses.

When damage to the vessels results in bleeding, blood platelets and certain proteins dissolved in the plasma, interact to create clots which block the ruptured areas of the blood vessels involved. This protects the body from further blood loss. Recall that body temperature is regulated via a negative-feedback loop. If you were exercising on a warm day, your rising core body temperature would trigger several homeostatic mechanisms, including increased transport of blood from your core to your body periphery, which is typically cooler.

As blood passes through the vessels of the skin, heat would be dissipated to the environment, and the blood returning to your body core would be cooler. In contrast, on a cold day, blood is diverted away from the skin to maintain a warmer body core. In extreme cases, this may result in frostbite. Blood also helps to maintain the chemical balance of the body. Proteins and other compounds in blood act as buffers, which help to regulate the pH of body tissues.

Blood also helps to regulate the water content of body cells. If you have had blood test, it was likely drawn from a superficial vein in your arm, which was then sent to a lab for analysis. Some of the most common blood tests—for instance, those measuring lipid or glucose levels in plasma—determine which substances are present within blood and in what quantities. Other blood tests check for the composition of the blood itself, including the quantities and types of formed elements.

One such test examines hematocrit, which measures the percentage of RBCs erythrocytes in a blood sample. It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma Figure Because the heaviest elements in blood are the erythrocytes, these settle at the bottom of the hematocrit tube.

Located above the erythrocytes is a pale, thin layer composed of the remaining formed elements of blood. These are the WBCs leukocytes and the platelets thrombocytes. This layer is referred to as the buffy coat, and it normally constitutes less than 1 percent of a blood sample. Above the buffy coat is the blood plasma, normally a pale, straw-colored fluid, which constitutes the remainder of the sample.

The volume of erythrocytes after centrifugation is also commonly referred to as packed cell volume. Typically, blood contains about 45 percent erythrocytes, however, samples can vary significantly from about 36—50 percent. The percentage of other formed elements, the WBCs and platelets, is extremely small so it is not normally considered with the hematocrit.

When you think about blood, the first characteristic that probably comes to mind is its color. Blood that has just taken up oxygen in the lungs is bright red, and blood that has released oxygen in the tissues is a darker red. This is because hemoglobin is a pigment that changes color, depending upon the degree of oxygen saturation. Blood is viscous, with a viscosity approximately five times greater than water.

The viscosity of blood has a dramatic impact on blood pressure and flow. Consider the difference in flow between water and honey.

The more viscous honey would demonstrate a greater resistance to flow than the less viscous water. The same principle applies to blood. Although, the surface of blood vessels is relatively smooth blood experiences friction and resistance as it flows.

This produces heat, accounting for the slightly higher temperature of blood. The pH of blood averages about 7. Blood is therefore somewhat more basic alkaline on a chemical scale than pure water, which has a pH of 7. Blood contains numerous buffers that help to regulate pH. Blood constitutes approximately 8 percent of adult body weight. Adult males typically average about liters of blood, and females average 4—5 liters.

Dissolved or suspended within this water is a mixture of substances, most of which are proteins. There are hundreds of substances dissolved in the plasma, although many of them are found only in very small quantities.

Visit this site for a list of normal levels established for many of the substances found in a sample of blood. Serum, one of the specimen types included, refers to a sample of plasma after clotting factors have been removed.

What types of measurements are given for levels of glucose in the blood? Approximately 7 percent of the plasma that is not water is made of proteins. These include several plasma proteins proteins that are unique to the plasma , plus a much smaller number of regulatory proteins, including enzymes and hormones.

The major components of plasma are summarized in Figure In addition to proteins, plasma contains a wide variety of other substances. These include various electrolytes, such as sodium, potassium, and calcium ions; dissolved gases, such as oxygen, carbon dioxide, and nitrogen; various organic nutrients, such as vitamins, lipids, glucose, and amino acids; and metabolic wastes. All of these non-protein solutes combined contribute approximately 1 percent to the total volume of plasma.

When more than a few drops of blood are required, phlebotomists perform a venipuncture, typically of a surface vein in the arm. They perform a capillary stick on a finger, an earlobe, or the heel of an infant when only a small quantity of blood is required.

An arterial stick is collected from an artery and used to analyze blood gases. After collection, the blood may be analyzed by medical laboratories or perhaps used for transfusions, donations, or research.

While many allied health professionals practice phlebotomy, the American Society of Phlebotomy Technicians issues certificates to individuals passing a national examination, and some large labs and hospitals hire individuals expressly for their skill in phlebotomy. Medical or clinical laboratories employ a variety of individuals in technical positions:.

Blood is a fluid connective tissue critical to the transportation of nutrients, gases, and wastes throughout the body; to defend the body against infection and other threats; and to the homeostatic regulation of pH, temperature, and other internal conditions.

Blood is composed of formed elements—erythrocytes, leukocytes, and cell fragments called platelets—and a fluid extracellular matrix called plasma. More than 90 percent of plasma is water. The remainder is mostly plasma proteins—mainly albumin, globulins, and fibrinogen—and other dissolved solutes such as glucose, lipids, electrolytes, and dissolved gases. Because of the formed elements and the plasma proteins and other solutes, blood is more viscous than water.

It is also slightly alkaline, and its temperature is slightly higher than normal body temperature. There are values given for percent saturation, tension, and blood gas, and there are listings for different types of hemoglobin. True or false: The buffy coat is the portion of a blood sample that is made up of its proteins.

Skip to content Learning Objectives By the end of this section, you will be able to: Identify the primary functions of blood, its fluid and cellular components, and its characteristics Identify the primary functions of blood in transportation, defense, and maintenance of homeostasis Identify the primary proteins and other solutes present in blood plasma Name the fluid component of blood and the three major types of formed elements, and identify their relative proportions in a blood sample.

Figure Composition of Blood: The cellular elements of blood include a vast number of erythrocytes and comparatively fewer leukocytes and platelets. Plasma is the fluid in which the formed elements are suspended. A sample of blood spun in a centrifuge reveals that plasma is the lightest component. It floats at the top of the tube separated from the heaviest elements, the erythrocytes, by a buffy coat of leukocytes and platelets.

Hematocrit is the percentage of the total sample that is comprised of erythrocytes. Depressed and elevated hematocrit levels are shown for comparison. External Website Visit this site for a list of normal levels established for many of the substances found in a sample of blood. They perform a wide variety of tests on various body fluids, including blood.

The information they provide is essential to the primary care providers in determining a diagnosis and in monitoring the course of a disease and response to treatment. Medical laboratory assistants MLA spend the majority of their time processing samples and carrying out routine assignments within the lab.

Clinical training is required, but a degree may not be essential to obtaining a position. Chapter Review Blood is a fluid connective tissue critical to the transportation of nutrients, gases, and wastes throughout the body; to defend the body against infection and other threats; and to the homeostatic regulation of pH, temperature, and other internal conditions. Interactive Link Questions Visit this site for a list of normal levels established for many of the substances found in a sample of blood.

Review Questions. Critical Thinking Questions 1. Why would it be incorrect to refer to the formed elements as cells? The formed elements include erythrocytes and leukocytes, which are cells although mature erythrocytes do not have a nucleus ; however, the formed elements also include platelets, which are not true cells but cell fragments. The buffy coat is the portion of blood that is made up of its leukocytes and platelets.

Functions of the Blood: 8 Facts about Blood

Discuss the structure and function of erythrocytes red blood cells and hemoglobin. The erythrocyte , commonly known as a red blood cell or RBC , is by far the most common formed element: A single drop of blood contains millions of erythrocytes and only thousands of leukocytes Figure Specifically, males have about 5. In fact, erythrocytes are estimated to make up about 25 percent of the total cells in the body. Although leukocytes typically leave the blood vessels to perform their defensive functions, movement of erythrocytes from the blood vessels is abnormal.

Blood is made of of several components, including red blood cells, white blood cells, platelets, and the plasma, which contains coagulation factors and serum. Blood helps maintain homeostasis by stabilizing pH, temperature, osmotic pressure, and by eliminating excess heat. Blood supports growth by distributing nutrients and hormones, and by removing waste. These cells deliver oxygen to the cells and remove carbon dioxide. Blood plays a protective role by transporting clotting factors and platelets to prevent blood loss after injury.


(a) The structure of red blood cells, white blood cells, and platelets. (6) Blood cells and list the proteins of blood plasma and state their functions;. • name the​.


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NCBI Bookshelf. Dean L. The average human adult has more than 5 liters 6 quarts of blood in his or her body.

The heart pumps blood through a vast network of arteries and veins. Blood is a living fluid. It transports oxygen and other essential substances throughout the body, fights sickness, and performs other vital functions. Below are 8 important facts about blood. Because of these living cells suspended in the plasma, blood is considered a fluid connective tissue not a fluid.

Blood , fluid that transports oxygen and nutrients to the cells and carries away carbon dioxide and other waste products. Technically, blood is a transport liquid pumped by the heart or an equivalent structure to all parts of the body, after which it is returned to the heart to repeat the process. Blood is both a tissue and a fluid. It is a tissue because it is a collection of similar specialized cells that serve particular functions.

Components of blood

The liquid component of the blood in which the following blood cells are suspended:. Red blood cells erythrocytes. These carry oxygen from the lungs to the rest of the body. White blood cells leukocytes. These help fight infections and aid in the immune process. Types of white blood cells include:. Blood cells are made in the bone marrow.

Genetics, Structure and Function of Blood Cells contains the proceedings of the symposia of the 28th International Congress of Physiology held in Budapest between 13 and 19 of July, Organized into six parts, this book begins with a discussion on the genetic regulation of hemoglobin synthesis. Parts II and III describe the immunoglobulin receptors and their effectors, and antenatal development of human blood cells. Subsequent parts talk about regulation of differentiation of hemoglobin structure and function and the role of calcium in red cell membrane transport processes. The last part elucidates the structure and function of blood cell membranes. We are always looking for ways to improve customer experience on Elsevier. We would like to ask you for a moment of your time to fill in a short questionnaire, at the end of your visit.

Blood , fluid that transports oxygen and nutrients to the cells and carries away carbon dioxide and other waste products. Technically, blood is a transport liquid pumped by the heart or an equivalent structure to all parts of the body, after which it is returned to the heart to repeat the process. Blood is both a tissue and a fluid. It is a tissue because it is a collection of similar specialized cells that serve particular functions. These cells are suspended in a liquid matrix plasma , which makes the blood a fluid. If blood flow ceases, death will occur within minutes because of the effects of an unfavourable environment on highly susceptible cells. The constancy of the composition of the blood is made possible by the circulation , which conveys blood through the organs that regulate the concentrations of its components.


PDF | The structure of red blood cells is affected by many inborn and acquired factors, but in most cases this does not seem to affect their.


What is the function of blood?

Identify the primary functions of blood, its fluid and cellular components, and its characteristics. Recall that blood is a connective tissue. Like all connective tissues, it is made up of cellular elements and an extracellular matrix. The cellular elements—referred to as the formed elements —include red blood cells RBCs , white blood cells WBCs , and cell fragments called platelets. The extracellular matrix, called plasma , makes blood unique among connective tissues because it is fluid. This fluid, which is mostly water, suspends the formed elements and enables them to circulate throughout the body within the cardiovascular system.

18.1 Functions of Blood

Я был ослеплен своими амбициями.

 - Он покачал головой и возобновил работу. Дэвид Беккер стоял в центре пустого зала и думал, что делать. Весь вечер оказался сплошной комедией ошибок. В его ушах звучали слова Стратмора: Не звони, пока не добудешь кольцо.

Последняя защитная стенка на центральном экране почти совсем исчезла. Черные линии, сбившись в кучу вокруг ядра, настолько сгустились, что их масса стала совсем непрозрачной и легонько подрагивала. Мидж отвернулась. Фонтейн стоял очень прямо, глядя прямо перед. У Бринкерхоффа был такой вид, словно он вот-вот лишится чувств.

Genetics, Structure and Function of Blood Cells

Тогда откуда же пришла команда на ручное отключение.

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