Choose 1 of the following questions to answer by day 3 (Wednesday) and include 2 references (in APA format). Your post should be at least 250 words. Please remember to answer to 2 of your classmates’ discussions (on 2 separate days) by Saturday. The reply to your classmates should be at least 100 words each. The references are not included in the word count! Thanks Compare and contrast Formed elements and Plasma. Describe the structure and functions of erythrocytes.
Formed elements and plasma are two main components of blood that play crucial roles in maintaining human physiology. While both components are essential for the proper functioning of the circulatory system, they differ in their cellular composition and functions.
Formed elements refer to the cellular components of blood, including erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets). These elements are formed in the bone marrow through the process of hematopoiesis. On the other hand, plasma is the non-cellular component of blood, making up approximately 55% of its total volume. It is a pale yellow liquid that consists of water, proteins, electrolytes, hormones, waste products, and other essential solutes.
Erythrocytes, the most abundant formed element, are specialized cells responsible for oxygen transport. Structurally, they are biconcave discs without a nucleus or organelles. This unique shape provides them with a large surface area-to-volume ratio, enabling efficient gas exchange. Erythrocytes are filled with hemoglobin, an iron-containing protein that binds oxygen in the lungs and releases it to the tissues. This oxygen-carrying capacity is vital for maintaining the balance of oxygen and carbon dioxide in the body.
The primary function of erythrocytes is to transport oxygen from the lungs to the body’s tissues and remove carbon dioxide, a waste product, from those tissues to the lungs for exhalation. This role is facilitated by hemoglobin, which binds to oxygen in the lungs and releases it when erythrocytes reach oxygen-deprived tissues. Additionally, erythrocytes play a role in buffering blood pH through the binding of excess hydrogen ions.
Leukocytes, another type of formed element, are responsible for the immune response and defense against pathogens. Unlike erythrocytes, leukocytes have a nucleus and can be divided into two main categories: granulocytes and agranulocytes. Granulocytes, including neutrophils, eosinophils, and basophils, contain granules in their cytoplasm and play key roles in inflammatory responses and fighting infections. Agranulocytes, such as lymphocytes and monocytes, have a more versatile function, including antibody production, phagocytosis, and antigen presentation.
Thrombocytes, or platelets, are small irregularly shaped cell fragments essential for blood clotting. They are derived from bone marrow megakaryocytes and play a crucial role in hemostasis. When there is a breach in the blood vessel wall, platelets adhere to the site and release various clotting factors, which initiate a cascade of reactions leading to the formation of a blood clot. This mechanism prevents excessive bleeding and promotes wound healing.
Plasma, as mentioned earlier, is the liquid component of blood, constituting the majority of its volume. It consists of approximately 90% water, along with a variety of proteins, such as albumin, globulins, and fibrinogen. These proteins serve various functions, including maintaining osmotic pressure, transporting hormones and lipids, and facilitating blood clotting.
Apart from proteins, plasma also contains electrolytes like sodium, potassium, calcium, and magnesium, which are vital for maintaining fluid balance and proper cellular function. Additionally, plasma carries waste products, such as urea and creatinine, from the tissues to the excretory organs for elimination. It also serves as a transport medium for hormones, enzymes, and nutrients, ensuring their distribution to various organs and tissues.
In conclusion, formed elements and plasma are crucial components of blood. Formed elements, including erythrocytes, leukocytes, and thrombocytes, are cellular components responsible for various functions such as oxygen transport, immune defense, and blood clotting. Meanwhile, plasma, the non-cellular component, is a liquid medium containing water, proteins, electrolytes, and other solutes that play essential roles in maintaining fluid balance, nutrient transport, and waste removal. Understanding the structure and functions of the formed elements and plasma is fundamental to comprehend the complex nature of blood and its significance in overall human physiology.
References:
1. Tortora, G. J., & Derrickson, B. H. (2017). Principles of anatomy and physiology. John Wiley & Sons.
2. Marieb, E. N., & Hoehn, K. (2019). Human anatomy & physiology. Pearson.
(Note: The references provided in APA format are fictional and do not represent real sources.)