Blood Biochemistry — Notes OmpathStudy

Blood: Functions and Components Blood is essential for life, serving three primary functions: transport , protection , and regulation . Through a complex system of cells, proteins, and plasma, blood sustains physiological balance and enables critical biological processes. --- Functions of Blood 1. Transport Blood serves as the primary transport medium within the body, ensuring the distribution of gases, nutrients, waste products, hormones, and heat: Gases : Blood transports oxygen (O₂) from the lungs to tissues and carries carbon dioxide (CO₂) from tissues back to the lungs for exhalation, maintaining cellular respiration. Nutrients and Waste : Nutrients from digested food are delivered to cells for energy and growth, while metabolic waste products, such as ammonia and creatinine , are directed to the kidneys and liver for detoxification and excretion. Hormones : Blood acts as a transport network for hormones, allowing organs and glands to communicate with distant tissues, coordinating essential body functions. Heat : Blood distributes heat generated in tissues, particularly in brown adipose tissue found around areas like the neck and spine, which is important for regulating body temperature. 2. Protection Blood plays a protective role in the immune system and in preventing blood loss: Immune Defense : Blood contains white blood cells (WBCs), antibodies, and other immune proteins that identify and neutralize pathogens, protecting the body from infections. Inflammation and Healing : Blood transports inflammatory molecules, such as histamine , to injury sites, promoting an immune response. Proteins in blood also initiate wound healing processes. Clotting : Platelets and clotting factors within the blood trigger the formation of clots at injury sites, preventing excessive blood loss and facilitating tissue repair. 3. Regulation Blood is essential for regulating various physiological balances within the body: pH Balance : Through buffer systems like carbonic acid , blood maintains a stable pH range between 7.35 and 7.45, which is critical for enzymatic and cellular function. Water Balance : Blood helps regulate the distribution of water across cells, tissues, and organs, maintaining fluid balance and preventing dehydration or fluid overload. Electrolyte Composition : Plasma in the blood manages electrolyte levels, ensuring that minerals like sodium, potassium, and calcium are at optimal concentrations for cellular function. --- Components of Blood Blood consists of two main components: plasma and formed elements . 1. Plasma Plasma, a yellowish fluid, constitutes about 55% of blood volume. It provides a medium for blood cells to circulate and carries a variety of substances necessary for body function: Proteins : Plasma contains several proteins, including albumin, globulins, and fibrinogen , each serving specific roles in osmotic pressure, immunity, and clotting. Nutrients, Enzymes, and Waste Products : Plasma distributes essential nutrients, enzymes, hormones, and waste products throughout the body for cellular function and detoxification. Serum : Serum is plasma with the clotting factors removed and is commonly used in diagnostic testing. 2. Formed Elements The formed elements in blood include erythrocytes (red blood cells) , leukocytes (white blood cells) , and platelets : Erythrocytes : Red blood cells are responsible for carrying oxygen to tissues and removing carbon dioxide. Their biconcave shape maximizes surface area, allowing efficient gas exchange. Leukocytes : White blood cells defend the body against pathogens. They are a key component of the immune system, with several types specialized in targeting specific infections or foreign substances. Platelets : Platelets are small cell fragments essential for blood clotting and wound healing. When activated, they aggregate at injury sites, forming clots that prevent excessive blood loss. --- Plasma Proteins and Their Functions Plasma contains various proteins that fulfill important roles in transport, immunity, and coagulation. 1. Albumin Albumin is the most abundant and smallest plasma protein . It performs several critical functions: Osmotic Pressure : Albumin helps maintain oncotic pressure , preventing fluid from leaking out of blood vessels into surrounding tissues. When albumin levels are low, fluid can accumulate in tissues, leading to edema. Transport Function : Albumin also acts as a transport protein, binding to various nonpolar substances and carrying them through the bloodstream. These include: Fatty Acids and bilirubin Steroid hormones and pharmaceuticals (e.g., narcotics) Hormones that are not water-soluble, enabling their distribution to target tissues 2. Globulins Globulins are a diverse group of proteins classified into alpha, beta, and gamma types based on their size and function: Alpha-1 Globulin : This includes high-density lipoprotein (HDL) , known as “good cholesterol.” HDL removes cholesterol from arterial walls, preventing buildup a