Blood. Part 1.

Summary

The script provides a detailed overview of human blood composition and its essential properties. It explains the ratio of blood elements, plasma components, and specific functions of blood proteins like albumins, globulins, and fibrinogen. Key topics include red and white blood cells, hematocrit levels, pH balance, osmotic and oncotic pressures, and the body's mechanisms for regulating these parameters. It also discusses the role of blood components in immunity, blood clotting, and homeostasis, along with practical aspects like blood tests and conditions such as anemia and leukocytosis.

Takeaways

• 🩸 The human body contains about 5 liters of blood, which consists of plasma and formed elements (red blood cells, white blood cells, and platelets).
• 🧪 Hematocrit refers to the ratio between blood formed elements and plasma, with normal values around 0.4-0.45.
• 💧 Plasma consists of water and dissolved substances, including organic (proteins, glucose, urea) and inorganic components (sodium, potassium, phosphates).
• 🧬 Blood plasma proteins include albumins (about 60% of blood proteins, responsible for oncotic pressure), globulins (involved in defense, including immunoglobulins/antibodies), and fibrinogen (important for blood clotting).
• 🌡️ Red blood cells (erythrocytes) transport oxygen and carbon dioxide, contain hemoglobin, and are crucial for diagnosing conditions like anemia and inflammation through the erythrocyte sedimentation rate (ESR).
• 🦠 White blood cells (leukocytes) are fewer than red blood cells, with normal levels ranging from 4,000 to 9,000 per microliter of blood. Elevated levels (leukocytosis) indicate inflammation or physiological responses (e.g., exercise or pregnancy).
• 🔬 Leukocyte formula analysis helps distinguish between types of leukocytosis, with pathological leukocytosis involving a shift to the left in young neutrophil counts.
• 🦋 Granulocytes (neutrophils, basophils, eosinophils) and agranulocytes (monocytes, lymphocytes) play different roles in immune response, with eosinophils increasing in allergic reactions or parasitic invasions.
• 💥 Hemolysis (destruction of red blood cells) can be mechanical, biological, chemical, thermal, or osmotic, with isotonic solutions (e.g., 0.9% saline) used to avoid osmotic hemolysis.
• 🔄 The pH of blood is tightly regulated (normal range: 7.36) through buffer systems (hemoglobin, carbonate, phosphate, and protein buffers), kidneys, respiration, and other mechanisms to prevent acidosis or alkalosis.

Q & A

What are the two main components of blood?

Blood consists of plasma and formed elements, which include red blood cells, white blood cells, and platelets.

What is hematocrit and what are its normal values?

Hematocrit is the ratio between the formed elements and plasma in the blood. The normal value of hematocrit is between 0.40 and 0.45.

What is the difference between plasma and serum?

Plasma is the liquid portion of blood that contains water, proteins, and other substances. Serum is plasma without fibrinogen, a protein used for blood clotting.

What are albumins, and what are their main functions?

Albumins are the lightest proteins in blood plasma, making up about 60% of total blood proteins. They are responsible for maintaining oncotic pressure, transporting hormones and biologically active molecules, and serving as a nutritional source during starvation.

What is the role of gamma globulins in the immune system?

Gamma globulins, also known as immunoglobulins, are antibodies produced by B lymphocytes. They bind to antigens (foreign proteins) to neutralize them, playing a crucial role in the immune defense.

What is erythrocyte sedimentation rate (ESR), and what does an increase indicate?

ESR measures how fast red blood cells settle at the bottom of a test tube in one hour. An increase in ESR usually indicates inflammation, but it can also rise during pregnancy, cancer, or other conditions.

What is leukocytosis and what are its types?

Leukocytosis is an increase in white blood cell count. It can be physiological (caused by pregnancy, physical exercise, or food consumption) or pathological (caused by infections or inflammation).

What happens during osmotic hemolysis?

Osmotic hemolysis occurs when water moves into red blood cells, causing them to swell and burst. This can happen if a hypertonic solution is added to the blood, leading to cell damage.

What is the role of buffer systems in maintaining blood pH?

Buffer systems help maintain a stable blood pH. The major buffer systems in the blood include hemoglobin, carbonic acid-bicarbonate, phosphate, and protein buffers. These systems neutralize excess acids or bases to keep the pH within a narrow range.

How does respiration affect blood pH?

Respiration can influence blood pH by regulating the amount of carbon dioxide (CO2) in the blood. Rapid breathing removes CO2, causing alkalosis (increased pH), while slow breathing retains CO2, which can lead to acidosis (decreased pH).