Answer

  Blood is the most predominant fluid in humans and animals that help transport essential substances such as oxygen and nutrients to cells as well as moving metabolic wastes from body cells. The main wastes carried from cells by blood is carbon dioxide. Therefore, blood is essentially a transporting fluid that moves from one body organ to another because of the heart’s pumping force.

1. TASK 1: Function and Composition Of Blood
2. Principal components of Blood

Blood is made up of two major components; fluid and cells as shown in figure 1. The fluid is mainly plasma, which makes up about half of the content of blood in the human body. According to Schwartz & Conley (2019), the primary functions of the plasma is to transport substances through the blood as they dissolve in it. On the other hand, cellular components of blood include red booed cells (RBCs) whose primary function is to carry oxygen and carbon dioxide to and away from particular cells, white blood coals (WBCs) whose main duty is to fight body infections and platelets that are smaller in nature and help in the clotting process. Primarily, the veins that carry blood are smooth and finely balanced to prevent clotting within them.

Figure 1: Different components of Blood. Source: Molnar, C. and Gair, J. (2019). Concepts of Biology-1st Canadian Edition

1. Functions of Blood

The overall function of the blood is to maintain specific suitable conditions within the body’s internal environment. In this regard, blood achieves this objective by continually adapting to changing life conditions especially varying atmospheric pressure and climate. Therefore, the blood has a complicated structure, which is developed by different components in unison. In this regard, blood helps in achieving a consistent oxygen supply to the cells especially brain cells, which are highly susceptible in the event of oxygen depreciation.

Nutrition is another significant duty of the blood. Ideally, the blood moves all substances required for cell nutrition to the target tissues or cells. The blood also functions to maintain the body’s immunity. In this regard, it destroys and protects against the entry of infectious agents mainly through the blood cells. Another function is the maintenance of proper body temperature.

TASK 2: Red Blood Cells Formation and Maturity

1. The Formation Of Blood Cells

Blood cells are formed through processes called Hematopoiesis. Ideally, the procedure takes place in the bone marrow, which is found in long bones. Ideally, the bone marrow contains stem cells that are responsible for making different types of blood cells. The most abundant stem cells are the pluripotential stem cells. The stem cells can differentiate into two distinct types of stem cells for making different blood cells. The two types are the lymphoid and myeloid stem cells. Therefore, all blood cells; platelets, WBCs, and RBCs are produced in the bone marrow. However, two distinct types WBCs called B, and T cells also known as lymphocytes are produced in the spleen and lymph nodes (Rodrigues & Granger, 2015). Primarily, T cells mature within the thymus glands. Stem cells produce blood cells by dividing to result in immature blood cells. The immature blood cells also undergo division to form more cells.

1. How Red Blood cells mature.

Formation of red blood cells occurs within the bone marrow trough cell division. The division is followed by maturing meaning that blood cells mature within the bone marrow. The production of blood is affected by aging as the bone marrow’s rate of blood cell production reduces.

TASK 3: Red Blood Cells Structure and Function

1. The Structure and Function Of RBCs

The RBCs are among the most vital components of the blood. Primarily, they are adapted to their oxygen-carrying duty as they are not nucleated as shown in figure 2. The size of one red blood cell is about 0.0002042 of an inch in diameter. There are biconcave shaped to have a large surface to volume ratio. Under a microscope, RBCs paper like yellow-green disks with no visible internal elements. Usually, RBC count per cubic millimeter ranges between six to four million. Primarily, RBCs can tolerate folding and bending but can be destroyed by extreme stretching force. Usually, RBCs are enclosed in a membrane that is permeable to oxygen, carbon dioxide, urea, glucose, and water. However, it is not permeable to hemoglobin. RBCs are affected by varying osmotic pressures and take in water in hypotonic solutions thereby becoming spheroid. On the other hand, they shrink when in concentrated salt solutions as they lose water.

Figure 2: Red Blood cells. They lack a nucleus

1. Role of RBCs – Hemoglobin

The primary purposes of RBCs is to carry oxygen to various body organs through the process of oxhaemoglobin.

Hemoglobin

The primary function of RBCs is respiration especially transportation of oxygen. In this regard, hemoglobin plays a significant role in this function. Primarily, oxygen combines with hemoglobin after passing through the plasma. In the process, pH influences the amount of oxygen that binds up with hemoglobin in a procedure referred to as the Bohr Effect. In this regard, low pH leads to low hemoglobin oxygen binding rate.

1. Recycling of RBCs

Red blood cells are recycled in the liver or spleen after being in existence for about 120 days. Primarily, about 90% of RBC are destroyed in the spleen after being taken there by macrophages while the other 10% is destructed while in circadian then picked up by macrophages. Macrophages are responsible for recycling RBCs through engulfing. In this regard, they engulf the RBCs and place it in a vacuole before fusing them with various lysosomes (Hoffman, 2019). The lysosomes have enzymes that break down the RBCs. However, one of the primary adaptation of RBCs in transporting oxygen is having hemoglobin as the only organelle. Therefore, the breakdown only focuses on hemoglobin breaking it down into the globin and heme group as shown in figure 3. The protein heme is continuously broken down into constituent amino acids including bilirubin and iron. The iron and amino acids are then transported to the bone marrow for use in creating new RBCs and haemoglobin.

Figure 3 Hemoglobin with oxygen. Source: Molnar, C. and Gair, J. (2019). Concepts of Biology-1st Canadian Edition

TASK 4: WBCs Structure and Function

1. The Structure of WBCs

White blood cells (WBCs) are motile and nucleated. They are highly differentiated for their functions and do not undergo cell division. Their primary function is protecting the body against infections, and their number ranges from 11,000 to 4,500 in each cubic millimeters. Their values in the body can be increased by intense physical exercise and exist both outside and within the blood circulation (Schwartz & Conley, 2019). WBCs can lead to the production of ribonucleic acid for protein synthesis. There are three groups of WBCs including lymphocytes, monocytes, and granulocytes as shown in figure 4. Their sizes vary depending on their category with granulocytes being about 13 μm in diameter. Some like neutrophils have lobes with hair like filaments appearing to join them.

Figure 4: Structure of different types of WBCs. Granulocytes have a lobbed nucleus while agranulocytes are first responders to immunity issues. Source: Molnar, C. and Gair, J. (2019). Concepts of Biology-1st Canadian Edition

1. Immunity function of White Blood Cells

Different roles aimed at enhancing the body’s defense system are carried out by varying categories of WBCs. Primarily, monocytes and granulocytes phagocytize harmful microorganisms after which they take them to regions of dead tissues for elimination (Hoffman, 2019). On the other hand, lymphocytes help in the establishment of immunity where coordination with antibodies is established to eliminate microbes.

TASK 5: Haemostasis

Haemostasis refers to a sequence of events that stop bleeding to prevent blood loss. The procedure begins as a reaction to injury to blood vessels. In this regard, the first step is vasoconstriction in which the damaged vessels constrict to limit the amount of blood flowing through (Schwartz & Conley, 2019, pg. 2). Next is the plug formation by platelets, which adhere to the damaged surface under the regulation of thromboregulation. After that, a clot is formed which prevent the flow of blood outside. Consequently, the wound healing procedure begins.

Figure 5: Platelets formation from megakaryocyte and clot development. Source: Molnar, C. and Gair, J. (2019). Concepts of Biology-1st Canadian Edition

Haemostasis occurs through three significant phases.

Vascular Spasm

During this process, the muscles in the damaged vessels contradict upon injury. Usually, these muscles have both longitudinal and circular layers. As such, circular layers constrict blood flow while longitudinal layers tend to draw the damaged blood vessel back to the surrounding tissue (Schwartz & Conley, 2019, pg. 2). The vascular spasm process is activated by endothelins released by cells that line up the vessels. Vascular spasm lasts for about 30 minutes in most cases.

Platelet Plug Formation

Platelets plug together binding to the endothelial lining and the exposed collagen. The process usually relies on the von Willebrand factor that is present in the blood plasma. As platelets continue to clog, they further enhance the haemostasis process releasing

• Adenosine diphosphate (ADP)-helps in the expansion of the clit
• Serotonin-enhances the process off vasoconstriction
• Phospholipids and prostaglandins-maintains vasoconstriction.

Coagulation

Involves blood clot formation.  It comprises production of a gelatinous clot that is robust and made of fibrin mesh. Primarily, fibrin is an insoluble protein that is filamentous and is usually derived from fibrinogen. As per Schwartz & Conley (2019, pg. 2), fibrin is utilised in the process called fibrinolysis in which proteins in the platelets contract to pull on fibrin strands thereby bringing the clot edges closer to each other. The process can sometimes wring out a petite amount of fluid called serum.

Primarily, fibrin plays a significant role in coagulation. Ideally, fibrin is synthesised from fibrinogen. Fibrinogen is protein in nature, is soluble, and is produced by the liver then exists within the blood plasma. Primarily, rapturing of blood vessels activates fibrinogen conversation into fibrin at the damaged point through the actions of a clotting enzyme called thrombin.