Carbon dioxide is produced as a waste product of cellular respiration, and it is deposited into the blood, so it can be brought to the lungs and exhaled. Blood transports hormones and nutrients throughout the body.
As we digest food, the villi of the small intestines absorb nutrients into the blood. Blood also transports waste substances to the kidneys and liver, which remove them and process them for elimination. Blood regulates body temperature. When the body needs to warm up or cool down, the circulatory system plays an important role.
This is called vasodilation. Blood protects the body from pathogens. Some white blood cells are specialized to engulf bacteria and other pathogens through a process called phagocytosis. Blood clots to prevent blood loss at sites of injury.
When a blood vessel tears, platelets in the area activate, connecting with other platelets to form a plug to prevent further blood loss. These platelets release enzymes that help a blood clot form. Blood cells are produced within red bone marrow. There are five types of white blood cells: neutrophils, basophils, eosinophils, monocytes, and lymphocytes.
Thirteen different blood clotting factors, in addition to platelets, need to interact for clotting to occur. They do so in a cascading manner, one factor triggering another. Hemophiliacs lack the ability to produce either blood factor 8 or 9. Platelets are not equally effective in clotting blood throughout the entire day. The body's circadian rhythm system its internal biological clock causes the peak of platelet activation in the morning. This is one of the main reasons that strokes and heart attacks are more common in the morning.
Recent research has shown that platelets also help fight infections by releasing proteins that kill invading bacteria and some other microorganisms.
In addition, platelets stimulate the immune system. They have a lifespan of days. Like the red and white blood cells, platelets are produced in bone marrow from stem cells. As the heart pumps blood to cells throughout the body, plasma brings nourishment to them and removes the waste products of metabolism. Plasma also contains blood clotting factors, sugars, lipids , vitamins, minerals, hormones , enzymes , antibodies , and other proteins.
It is likely that plasma contains some of every protein produced by the body--approximately have been identified in human plasma so far. Sometimes when the blood of two people is mixed together, it clumps or forms visible islands in the liquid plasma--the red cells become attached to one another. This is agglutination. When different types of blood are mixed within the body, the reaction can be a bursting of the red cells as well as agglutination.
Different types of blood are recognized on the molecular level and sometimes rejected by being destroyed and ultimately filtered out by the kidneys in order to expel them from the body along with urine.
In the case of a transfusion mistake, there can be so much of the wrong type of blood in the system that it can result in kidney failure and death.
This is due to the fact that when the kidneys try to filter the blood, they essentially become clogged as they are overwhelmed and cease being effective filters. Additionally, there is a rapid depletion of blood clotting factors which causes bleeding from every body orifice. In the United States, about 1 in 12, units of whole blood transfused is given to the wrong person.
Depending on the blood types of the donor and the recipient, this can result in death or no problems at all. The compositional difference between blood types is in the specific kinds of antigens found on the surface of the red cells. Antigens are relatively large protein molecules that provide the biological signature of an individual's blood type. Within blood, there are substances called antibodies which distinguish particular antigens from others, causing bursting or agglutination of the red cells when alien antigens are found.
The antibodies bind to the antigens. In the case of agglutination, the antibodies "glue" together the antigens from different red cells thereby sticking the red cells together as shown below on the right. This is not the same thing as clotting. In fact, some health organizations call plasma "the gift of life.
If you want to donate plasma to help others in need, you will go through a screening process. This is to make sure your blood is healthy and safe. If you qualify as a plasma donor, you'll spend about an hour and a half at a clinic on every follow-up visit.
During the actual blood donation process, your blood is drawn through a needle placed in a vein in one arm. A special machine separates the plasma and often the platelets from your blood sample. This process is called plasmapheresis.
The remaining red blood cells and other blood components are then returned to your body, along with a little saline salt solution.
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 nonprotein 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.
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 sticky and more viscous than water. It is also slightly alkaline, and its temperature is slightly higher than normal body temperature.
Answer the question s below to see how well you understand the topics covered in the previous section. Skip to main content. Chapter The Cardiovascular System. Search for:. An Overview of Blood Learning Objectives By the end of this section, you will be able to: Identify the primary functions of blood in transportation, defense, and maintenance of homeostasis Describe the general characteristics and functions of blood. Describe major blood disorders. Name the fluid component of blood and the three major types of formed elements, and identify their relative proportions in a blood sample Discuss the unique physical characteristics of blood Identify the composition of blood plasma, including its most important solutes and plasma proteins.
Practice Question Visit this site for a list of normal levels established for many of the substances found in a sample of blood. Show Answer There are values given for percent saturation, tension, and blood gas, and there are listings for different types of hemoglobin.
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. Why would it be incorrect to refer to the formed elements as cells?
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