What's inside of blood? | Lab values and concentrations | Health & Medicine | Khan Academy

khanacademymedicine
10 Dec 201211:09
EducationalLearning
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TLDRThis script provides an educational walkthrough of what happens after blood is drawn from a patient. It explains the process of blood collection into a special tube that prevents clotting and the subsequent lab work involving centrifugation. The script delves into the composition of blood, detailing the separation into plasma, white blood cells, platelets, and red blood cells. It further explains the significance of plasma's water content, the role of proteins like albumin and antibodies, and the importance of hematocrit, which measures the volume of red blood cells. The script also introduces terms like serum and contrasts it with plasma, while explaining conditions like polycythemia and anemia in relation to red blood cell volume.

Takeaways
  • πŸ’‰ The speaker is afraid of needles but complies with medical procedures for blood drawing.
  • πŸ§ͺ Blood is collected into a special tube that contains a chemical to prevent clotting.
  • 🚫 The importance of not allowing blood to clot is emphasized for accurate lab work.
  • πŸŒ€ Blood samples are processed in a centrifuge, which spins the tubes to separate blood components.
  • πŸ“Š After centrifugation, blood separates into three distinct layers: plasma, white blood cells and platelets, and red blood cells.
  • 🧬 Plasma makes up about 55% of the blood volume and is mostly water, with the rest being proteins, hormones, electrolytes, and nutrients.
  • πŸ›‘οΈ Albumin, antibodies, and fibrinogen are examples of proteins found in plasma that serve various functions in the body.
  • πŸ”¬ White blood cells and platelets constitute less than 1% of the blood and play a crucial role in the immune system and clotting.
  • ❀️ Red blood cells, which contain hemoglobin, make up about 45% of the blood volume and are responsible for oxygen transport.
  • 🩸 Serum is similar to plasma but without fibrinogen and clotting factors.
  • πŸ“ˆ Hematocrit measures the volume of red blood cells in relation to the total blood volume, and it can indicate conditions like polycythemia or anemia.
Q & A

  • Why does the narrator dislike getting their blood drawn?

    -The narrator dislikes getting their blood drawn because they are afraid of needles.

  • What is the first step taken with the blood after it is drawn?

    -The first step is to put the blood into a special tube that prevents clotting.

  • What is the purpose of the chemical on the walls of the blood collection tube?

    -The chemical on the walls of the tube prevents the blood from clotting, which is necessary for proper lab work.

  • How is the blood ensured to mix properly and not clot in the tube?

    -To ensure proper mixing and prevent clotting, people sometimes gently shake the tube.

  • What happens to the blood once it arrives at the lab?

    -The blood is placed into a machine that spins the blood at high speed, a process known as centrifugation.

  • What is the result of the centrifugation process?

    -Centrifugation causes the blood to separate into different layers due to the centrifugal force.

  • What are the three main layers of blood after centrifugation?

    -The three main layers are plasma on top, a thin layer of white blood cells and platelets in the middle, and red blood cells at the bottom.

  • What is plasma and what does it consist of?

    -Plasma is the liquid component of blood, making up about 55% of its volume, and consists mainly of water, proteins like albumin and antibodies, and other substances like hormones, electrolytes, and nutrients.

  • What is the difference between plasma and serum?

    -Plasma and serum are very similar, but serum does not include fibrinogen and clotting factors.

  • What does the term 'hematocrit' refer to?

    -Hematocrit refers to the volume of red blood cells divided by the total volume of blood, expressed as a percentage.

  • What medical conditions are indicated by a high or low hematocrit?

    -A high hematocrit indicates polycythemia, where there is a high volume of red blood cells relative to the total blood volume. A low hematocrit indicates anemia, where there is a low volume of red blood cells.

Outlines
00:00
πŸ’‰ Blood Collection and Processing

The script begins with a personal anecdote about the discomfort of having blood drawn due to a fear of needles. It then transitions into a detailed explanation of the process that follows blood collection. Blood is placed into a special tube designed to prevent clotting, thanks to a chemical coating on the tube's walls. To ensure the chemical is well-mixed, the tube may be gently shaken. The blood is then sent to a lab where it is subjected to centrifugation, a process that separates the blood into different components through rapid spinning. This results in a layered appearance with distinct parts, which will be elaborated on in subsequent paragraphs.

05:00
🧬 Blood Components and Their Functions

This paragraph delves into the components of blood separated by the centrifugation process. The top layer, plasma, is highlighted as the largest component, making up about 55% of the blood's volume. Plasma is primarily water, with the remainder consisting of proteins like albumin, antibodies, and fibrinogen, as well as other substances such as hormones, electrolytes, and nutrients. The middle, very thin layer contains white blood cells and platelets, which play crucial roles in immunity and clotting. The dense bottom layer is composed of red blood cells, which contain hemoglobin and make up about 45% of the blood's volume. The paragraph also introduces the terms serum and hematocrit, explaining their relation to plasma and the volume占比 of red blood cells, respectively.

10:01
🩸 Hematocrit and Blood Disorders

The final paragraph discusses the concept of hematocrit and its significance in assessing the health of an individual. Hematocrit is the percentage of blood volume occupied by red blood cells. The script uses a visual comparison of three vials of blood to illustrate variations in hematocrit levels. A normal hematocrit is indicated by a balanced proportion of plasma and red blood cells. Conditions such as polycythemia, characterized by a high hematocrit due to an excess of red blood cells, and anemia, indicated by a low hematocrit and insufficient red blood cells, are introduced. The paragraph emphasizes that hematocrit levels can be influenced by factors like age, gender, and altitude, and that it's an important measure for understanding blood health.

Mindmap
Keywords
πŸ’‘Blood Draw
A blood draw is the process of collecting blood from a patient for medical testing. It is a common procedure in healthcare that involves the use of a needle to extract blood into a tube. In the video's context, the speaker describes their personal experience with a blood draw and their aversion to needles, which sets the stage for the discussion on what happens to the blood after it is drawn.
πŸ’‘Needles
Needles are sharp, pointed instruments used to puncture the skin for various medical procedures, including blood draws. The speaker mentions their fear of needles, which is a common fear known as trypanophobia. This personal detail helps to humanize the speaker and connects with viewers who may share the same fear, making the educational content more relatable.
πŸ’‘Anti-coagulant
An anti-coagulant is a substance that prevents blood from clotting. In the script, the speaker explains that the blood collection tubes contain a chemical anti-coagulant to keep the blood from clotting, which is crucial for accurate lab analysis. This concept is central to understanding the preparation of blood samples for testing.
πŸ’‘Centrifugation
Centrifugation is a process that uses centrifugal force to separate substances of different densities. In the video, the speaker describes how blood samples are centrifuged to separate the plasma, white blood cells, platelets, and red blood cells into distinct layers. This process is essential for various blood tests and understanding the composition of blood.
πŸ’‘Plasma
Plasma is the liquid component of blood that makes up about 55% of its total volume. It is composed mainly of water, proteins, electrolytes, nutrients, and hormones. The speaker explains that plasma is the top layer after centrifugation and highlights its importance in blood composition and overall health.
πŸ’‘Proteins
Proteins are large molecules that play a wide range of roles in the body, including structural support, transport, and immune function. In the script, the speaker identifies albumin, antibodies, and fibrinogen as examples of proteins found in plasma, illustrating their functions and importance in the blood.
πŸ’‘White Blood Cells
White blood cells, or leukocytes, are an essential part of the immune system and play a crucial role in defending the body against infections and diseases. The speaker mentions that white blood cells, along with platelets, form a very thin layer in the blood sample after centrifugation, emphasizing their significance despite their small proportion in the blood.
πŸ’‘Red Blood Cells
Red blood cells, or erythrocytes, are the most abundant cells in the blood and are responsible for transporting oxygen from the lungs to the body's tissues. The speaker explains that red blood cells form the densest layer after centrifugation, making up about 45% of the total blood volume, and discusses the importance of hemoglobin contained within them.
πŸ’‘Serum
Serum is the liquid component of blood that remains after blood has clotted and the clotting proteins have been removed. It is very similar to plasma but lacks fibrinogen and other clotting factors. The speaker clarifies the difference between serum and plasma, highlighting the removal of clotting factors in serum, which is used for certain types of blood tests.
πŸ’‘Hematocrit
Hematocrit is the volume percentage of red blood cells in blood. It is a measure that can indicate various health conditions, such as anemia or polycythemia. The speaker uses the term to explain the proportion of red blood cells in the blood and how variations in hematocrit can be significant for diagnosing certain medical conditions.
πŸ’‘Anemia
Anemia is a condition characterized by a decrease in the number or quality of red blood cells or a lack of hemoglobin. The speaker describes anemia as having a low volume of red blood cells relative to the total blood volume, which can lead to a variety of symptoms and health issues.
πŸ’‘Polycythemia
Polycythemia is a condition where there is an abnormally high number of red blood cells in the blood. The speaker uses the term to describe a scenario where the red blood cell layer is very prominent after centrifugation, indicating a high hematocrit level and the presence of this medical condition.
Highlights

The speaker dislikes getting blood drawn due to a fear of needles.

Blood is drawn into a special tube that prevents clotting with a chemical on its walls.

To ensure the anti-clotting chemical mixes well, the tube is sometimes gently shaken.

Blood from multiple patients is processed in a lab using a machine.

The lab machine uses centrifugation to separate blood components.

Centrifugation creates layers in the blood due to differences in density.

Plasma, the top layer, makes up about 55% of blood volume and is mostly water.

Plasma contains proteins like albumin, antibodies, and clotting factors.

Hormones, electrolytes, and nutrients are also found in plasma.

The middle layer consists of white blood cells and platelets, which are crucial for immunity and clotting.

Red blood cells, with hemoglobin, make up the densest layer at the bottom, about 45% of blood volume.

Serum is similar to plasma but lacks fibrinogen and clotting factors.

Hematocrit measures the volume of red blood cells in relation to total blood volume.

Normal hematocrit values can vary based on age, gender, and altitude.

Polycythemia refers to a high volume of red blood cells relative to total blood volume.

Anemia is indicated by a low volume of red blood cells relative to total blood volume.

Transcripts

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Blood DrawMedical LabCentrifugationBlood ComponentsPlasma AnalysisHealth ScienceNeedle PhobiaHematocritPolycythemiaAnemia