blood and blood types

1.    Describe the components of human blood including formed elements and plasma components, including how prevalent each one is in blood.

Human blood consists of two main components: plasma and formed elements (cells).

Plasma: Makes up about 55% of blood. It is a yellowish fluid that contains:
Water (about 90%) which serves as a solvent.
Proteins such as albumin, globulins, and fibrinogen.
Electrolytes (e.g., sodium, potassium, calcium, chloride, bicarbonate).
Nutrients like glucose, amino acids, and lipids.
Hormones.
Waste products like urea and carbon dioxide.
Gases like oxygen and carbon dioxide.

Formed Elements: They make up about 45% of the blood. They include:
Red blood cells (RBCs): About 45% of blood volume, responsible for oxygen transport.
White blood cells (WBCs): Less than 1% of blood, responsible for immunity.
Platelets: Less than 1% of blood, involved in clotting

RBC Structure:

Connective tissue with cells suspended in liquid extracellular matrix (plasma)
No nucleus when mature (only mammals)
Hemoglobin (protein) that oxygen and carbon bind to

RBC Function:

Transports gases (O2 + CO2), nutrients, hormones, waste
Distributes heat
Maintains homeostasis

Platelets Structure:

Cytoplasmic fragments of large cell
Small chunks of cells

Platelets Function:

Produce protein (fibrin) when activated with clotting factors
Fibrin traps RBC and produces blood clot

Granulocytes?

Granulocytes
Definition: White blood cells that have visible granules in their cytoplasm when stained and viewed under a microscope.
Types:
Neutrophils – Most abundant, first responders to infection

engulf and destroy pathogens.
Eosinophils – Combat parasites and are involved in allergic reactions.
Basophils – Release histamine and other chemicals during allergic responses.
Nucleus: Multi-lobed nucleus.
Function: Mainly involved in innate immunity (nonspecific defense).
Appearance: Granular cytoplasm, lobed nuclei.

Agranulocytes?

Agranulocytes
Definition: White blood cells that lack visible granules in their cytoplasm.
Types:
Lymphocytes – Include B cells (make antibodies) and T cells (kill infected cells or help other immune cells).
Monocytes – Become macrophages or dendritic cells that engulf pathogens and present antigens.
Nucleus: Large, round or kidney-shaped nucleus.
Function: Primarily involved in adaptive immunity (specific defense).
Appearance: Clear cytoplasm, no granules, large nucleus.

Lymphocytes

Lymphocytes - Provides immunity by producing antibodies
🔹 Structure:
Size: Small to medium (about the same size or slightly larger than a red blood cell).
Nucleus: Large, round, and dark-staining, often takes up most of the cell volume.
Cytoplasm: Thin rim of pale blue cytoplasm around the nucleus

no visible granules.

🔹 Function:
Lymphocytes are central to adaptive immunity and are divided into:
B cells:
Function: Produce antibodies that neutralize pathogens.
Activation: When they encounter specific antigens.
Memory B cells: Provide long-term immunity.
T cells:
Helper T cells (CD4+): Activate B cells, other T cells, and macrophages.
Cytotoxic T cells (CD8+): Kill virus-infected cells and tumor cells.
Regulatory T cells: Help control immune responses to prevent autoimmunity.
Natural Killer (NK) cells:
Function: Part of innate immunity

kill virus-infected or cancerous cells without needing prior activation.

Monocytes

Monocytes - Phagocytizes large particles
🔹 Structure:
Size: Largest white blood cell.
Nucleus: Large, bean-shaped or kidney-shaped.
Cytoplasm: Abundant, pale blue to gray

lacks visible granules but may appear slightly grainy due to tiny lysosomes.

🔹 Function:
Part of the innate immune system.
Phagocytosis: Engulf and digest pathogens, dead cells, and debris.
After entering tissues, monocytes differentiate into:
Macrophages: Long-living cells that continue phagocytosis and help activate lymphocytes by presenting antigens.
Dendritic cells: Specialized antigen-presenting cells that link innate and adaptive immunity by activating T cells.

Neutrophils

Neutrophils - Phagocytizes small particles

🔹 Structure:
Nucleus: Multi-lobed (2–5 lobes), connected by thin strands.
Cytoplasm: Light pink with fine, neutral-staining granules (hard to see clearly under a microscope).
Most abundant WBC (~60–70% of circulating leukocytes).

🔹 Function:
First responders to infection or injury.
Use phagocytosis to ingest bacteria and dead cells.
Release enzymes and reactive oxygen species to destroy pathogens.
Form pus when they die in large numbers at infection sites.

Eosinophils

Eosinophils - Kills parasites and moderates allergic reactions
🔹 Structure:
Nucleus: Bi-lobed (two lobes).
Cytoplasm: Filled with large, red-orange granules (eosin-staining).

🔹 Function:
Combat parasitic infections (especially helminths).
Involved in allergic reactions (e.g., asthma, hay fever).
Release enzymes like histaminase to break down histamine.
Moderate inflammation.

Basophils

Basophils - Releases heparin and histamine // Triggers blood vessel dilation
🔹 Structure:
Nucleus: Bi-lobed or S-shaped, often hard to see due to dense granules.
Cytoplasm: Contains large, dark purple-blue granules that often obscure the nucleus.

🔹 Function:
Least common WBC.
Involved in allergic and inflammatory responses.
Granules contain:
Histamine – promotes vasodilation and increased permeability.
Heparin – prevents blood clotting.
Functionally similar to mast cells in tissues.

Phagocytizes

To engulf and digest particles like bacteria, dead cells, or debris.
It's the verb form of phagocytosis, a process used by certain cells—especially white blood cells—to "eat" harmful invaders or clean up messes in the body.

Describe hemoglobin’s synthesis requirements, structure and function.

Relate abnormal blood cell count to the following conditions: anemia, leukemia, parasitic infection, allergic reaction, bleeding.

Anemia: Low RBC count or hemoglobin levels, leading to fatigue and weakness.
Leukemia: Abnormal increase in WBCs, often immature or dysfunctional, leading to immune system problems.

Parasitic Infections: Increased eosinophil count as they combat parasites.

Allergic Reactions: Elevated eosinophil or basophil count.

Bleeding: Low platelet count (thrombocytopenia) impairs clotting, leading to excessive bleeding.

Define “complete blood cell count”.

A CBC is a test that measures the number of different types of blood cells (RBCs, WBCs, platelets) and provides information about overall health, anemia, infections, and other conditions.

Distinguish between antigens and antibodies.

Antigens: Molecules on the surface of cells (including red blood cells) that trigger immune responses.

Antibodies: Proteins in the blood that recognize and bind to specific antigens to neutralize them.

What is the main concern when blood is transfused from one individual to another?

The main concern is to match blood types to avoid hemolytic reactions, where the immune system attacks transfused blood due to incompatible antigens.

Define agglutination.

Agglutination is the clumping of red blood cells caused by the interaction between antigens on the surface of RBCs and antibodies in the plasma.

Define the universal donor and universal recipient and explain why these blood types are classified this way.

Universal Donor: Type O negative (O-), as it lacks A, B, and Rh antigens, so it won't trigger an immune response in most people.

Universal Recipient: Type AB positive (AB+), as it has both A and B antigens and the Rh factor, meaning it can accept any blood type without rejecting it.

Describe Rh+ and Rh-.

Rh+: Person has the Rh antigen on red blood cells (can receive Rh+ or Rh- blood).

Rh-: Person does not have the Rh antigen (can only receive Rh- blood to avoid an immune reaction).

Explain what might lead to erythroblastosis fetalis.

A condition in which the mother's immune system attacks the fetus’s RBCs if the fetus is Rh+ and the mother is Rh-. This happens when the mother's body produces antibodies against Rh antigens during pregnancy.

List most common types of blood. Explain the leading evolutionary hypothesis explaining the origin of blood types.

Most common: O+, A+, B+, AB+.
The leading evolutionary hypothesis suggests that blood types developed as adaptations to different environmental factors, such as resistance to diseases like malaria, which could explain the prevalence of certain blood types in different populations