Blood

Definition

Blood is a specialized connective tissue that consists of cells suspended in a liquid matrix called plasma. It plays a vital role in transporting oxygen, nutrients, hormones, and waste products throughout the body while also being essential for immune response and regulating body temperature. This unique tissue connects various systems of the body, making it integral to circulatory routes and regional circulation.

5 Must Know Facts For Your Next Test

1. Blood accounts for about 7-8% of total body weight, with an average adult having about 5-6 liters of blood.
2. There are four main blood types: A, B, AB, and O, which are determined by the presence or absence of specific antigens on the surface of red blood cells.
3. Platelets in blood are essential for clotting, helping to prevent excessive bleeding when injuries occur.
4. Blood helps regulate pH levels and electrolyte balance in the body, maintaining homeostasis.
5. The circulatory system can be divided into two main circuits: the pulmonary circuit, which oxygenates blood in the lungs, and the systemic circuit, which delivers oxygenated blood to the rest of the body.

Review Questions

• How does blood function as a transport medium within the circulatory system?
  • Blood functions as a transport medium by carrying oxygen from the lungs to tissues through red blood cells while also transporting carbon dioxide from tissues back to the lungs for exhalation. In addition to gases, it delivers nutrients absorbed from digestion to cells throughout the body. Furthermore, blood carries hormones from glands to target organs and helps remove metabolic waste products, ensuring that all body systems receive what they need to function efficiently.
• Discuss the significance of blood types in transfusions and how they relate to immune responses.
  • Blood types are significant in transfusions because receiving incompatible blood can trigger severe immune reactions. The presence of specific antigens on red blood cells determines an individual's blood type. For example, if someone with type A blood receives type B blood, their immune system may attack the foreign B antigens, leading to potentially life-threatening complications. Understanding blood types is critical for safe transfusion practices and organ transplants.
• Evaluate the role of blood in maintaining homeostasis within the human body and its impact on overall health.
  • Blood plays a crucial role in maintaining homeostasis by regulating temperature, pH levels, and fluid balance. Its ability to distribute heat helps control body temperature during physical activity or environmental changes. Additionally, through buffers present in plasma, blood helps maintain stable pH levels critical for enzyme function. Imbalances or dysfunctions in blood components can lead to health issues such as anemia, clotting disorders, or immune deficiencies, highlighting its importance for overall well-being.

Related terms

Plasma: The liquid component of blood that carries cells, nutrients, hormones, and waste products, making up about 55% of total blood volume.

Erythrocytes: Red blood cells responsible for transporting oxygen from the lungs to the body tissues and returning carbon dioxide from the tissues back to the lungs.

Leukocytes: White blood cells that are crucial to the immune system, helping to fight infections and protect the body against foreign invaders.