Blood Overview and Plasma Composition

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Questions and Answers

What type of hemoglobin is formed when hemoglobin binds to oxygen in the lungs?

Oxyhemoglobin (correct)

Methemoglobin

Deoxyhemoglobin

Carbaminohemoglobin

Which leukocyte is primarily involved in fighting parasites?

Eosinophils (correct)

Lymphocytes

Basophils

Neutrophils

What feature distinguishes granulocytes from agranulocytes?

Size differences

Role in immune response

Presence of nuclei

Presence of specific granules (correct)

Which leukocyte is the most abundant in the bloodstream?

Neutrophils (B) Signup and view all the answers

What is the primary function of neutrophils?

Engulf bacteria and microorganisms (A) Signup and view all the answers

What kind of immune response do basophils participate in upon second exposure to an antigen?

Histamine release (B) Signup and view all the answers

What do the specific granules of basophils primarily contain?

Histamine and heparin (C) Signup and view all the answers

What receptor type do eosinophils have on their membranes to assist in their immune function?

IgG and IgE receptors (D) Signup and view all the answers

What role does histamine play during an inflammatory response?

It promotes vasodilation and increases capillary permeability. (C) Signup and view all the answers

Which white blood cells are classified as granulocytes?

Neutrophils, eosinophils, and basophils (C) Signup and view all the answers

What is a key function of T lymphocytes when activated?

To directly attack foreign or virus-altered cells. (D) Signup and view all the answers

Which organ is primarily associated with the maturation of T lymphocytes?

Thymus (C) Signup and view all the answers

What distinguishes agranulocytes from granulocytes?

Agranulocytes do not have specific granules. (A) Signup and view all the answers

Which type of immunity is characterized as innate?

It provides immediate defense without previous contact with antigens. (A) Signup and view all the answers

What is the main function of B lymphocytes when activated?

To produce antibodies against specific antigens. (D) Signup and view all the answers

Which of the following is NOT a primary lymphoid organ?

Spleen (C) Signup and view all the answers

What distinguishes adaptive (acquired) immunity from innate immunity?

Adaptive immunity improves with each exposure to an antigen. (C) Signup and view all the answers

Which of the following cells are key components of the adaptive immune system?

B lymphocytes (B) Signup and view all the answers

What is the primary function of platelets during hemostasis?

Form clots to prevent bleeding. (C) Signup and view all the answers

What occurs immediately after vascular injury in the hemostatic process?

Von Willebrand factor and vasoconstrictors are released. (C) Signup and view all the answers

What do dense granules in platelets primarily contain?

Calcium ions, serotonin, ATP, and ADP. (A) Signup and view all the answers

During platelet adhesion, platelets bind to which molecule?

Von Willebrand factor (C) Signup and view all the answers

Which of the following best describes innate immunity?

Responds rapidly but in a non-specific manner. (C) Signup and view all the answers

What role do α (alpha) granules play in platelets?

Hold coagulation factors and fibrinogen. (B) Signup and view all the answers

What is the primary function of erythrocytes in the blood?

Transport oxygen and carbon dioxide (D) Signup and view all the answers

Which component of blood constitutes the largest percentage?

Plasma (D) Signup and view all the answers

What is the primary role of plasma proteins in the blood?

Maintaining osmotic pressure (A) Signup and view all the answers

How is the biconcave disc shape of erythrocytes advantageous?

It facilitates gas exchange and passage through capillaries. (A) Signup and view all the answers

What is the lifespan of an erythrocyte before it is typically destroyed?

120 days (A) Signup and view all the answers

What are the main components of plasma composition?

90% water, 9% proteins, and 1% nutrients/gases (C) Signup and view all the answers

What is the role of actin filaments in erythrocytes?

To maintain cell shape and assist in movement (D) Signup and view all the answers

What characteristic gives erythrocytes their red color?

The heme group in hemoglobin (C) Signup and view all the answers

Study Notes

Blood Overview

Blood is a specialized connective tissue, composed of blood cells (erythrocytes, leukocytes, and platelets) and a liquid matrix called plasma.
It is a viscous, slightly alkaline liquid that circulates throughout the circulatory system.
Blood transports substances, including nutrients from the digestive system to the rest of the body, waste products, hormones, respiratory gases (O2 and CO2), and immune cells, for disposal.
It also helps regulate body temperature and osmotic balance of tissues.

Plasma

Plasma is the liquid portion of blood, making up approximately 54% of blood volume.
It is a yellowish liquid in which cells, platelets, organic compounds, and electrolytes are dissolved or suspended.
Plasma is primarily composed of water (90%).
Other components include proteins (9%), nutrients, and respiratory gases (1%).
Plasma proteins maintain the osmotic pressure of blood and help maintain normal blood volume.
Plasma leaves capillaries and enters tissues as tissue fluid (with similar composition to plasma).

Erythrocytes (Red Blood Cells)

Erythrocytes are the most abundant formed elements in blood, with approximately 5 million per microliter.
They lack a nucleus and organelles but contain numerous enzymes for ATP production.
Their lifespan is about 120 days, after which they are destroyed in the liver, spleen, or bone marrow.
Their biconcave disc shape provides a large surface area for gas exchange (transport of O2 and CO2).
The shape is maintained by an actin cytoskeleton, requiring energy (ATP) for its function.

Transport of O2 and CO2

Erythrocytes contain hemoglobin, a protein with iron-containing heme groups, which gives blood its red color and facilitates oxygen transport.
In the lungs, where oxygen is abundant, hemoglobin binds to oxygen to form oxyhemoglobin.
In tissues, where oxygen is low and carbon dioxide is high, hemoglobin releases oxygen and binds to carbon dioxide, forming carbaminohemoglobin.

Leukocytes (White Blood Cells)

Leukocytes are larger than erythrocytes but less numerous.
They have nuclei and organelles and are not typically functional within the blood, but use it as a transport system to reach tissues where they perform their immune functions.
Leukocytes are classified into two main groups: granulocytes (polymorphonuclear cells) and agranulocytes.

Granulocytes

Granulocytes contain specific granules in their cytoplasm for particular immune functions.
Types of granulocytes:
- Neutrophils (most common): actively phagocytic, engulf bacteria and other microorganisms, contain enzymes with antibacterial functions.
- Eosinophils: have a bilobed nucleus, contain major basic protein to fight parasites, have receptors for IgG, IgE, and complement.
- Basophils: S-shaped nucleus masked by granules, contain heparin, histamine, eosinophil chemotactic factor, proteases, and peroxidase.

Agranulocytes

Agranulocytes do not contain specific granules in their cytoplasm.
Types of agranulocytes
- Monocytes: largest blood cell, kidney-shaped nucleus, remain in the blood for a short time and migrate to tissues where they differentiate into macrophages (for phagocytosis and immune function).
- Lymphocytes: small leukocytes, round nucleus, scarce cytoplasm, with different types (T cells, B cells, and NK cells) for various immune functions:
  - T cells are formed in the bone marrow, migrate to the thymus to mature and acquire immunocompetence.
  - B cells and NK cells are formed in the bone marrow and migrate to tissues to perform their role.
All cells types have lysosomes as non-specific granules.

Platelets

Platelets are the smallest formed elements in blood, disc-shaped fragments of megakaryocytes.
They lack nuclei but contain granules that are important for coagulation, and other functions.
Granules contain a variety of substances including coagulation factors, serotonin, ATP, ADP, and lysosomes.

Hemostasis

Platelets are essential for hemostasis (blood clotting), stopping bleeding.
The process involves vascular injury, platelet adhesion, aggregation, formation of a platelet plug, activation of the coagulation cascade.
This process leads to clot formation and eventual thrombus removal when the vessel is repaired.

Hematopoiesis

Hematopoiesis is the continuous, physiological process of blood cell formation.
All blood cells originate from pluripotent stem cells in the bone marrow (and in the liver and spleen in early development).
These cells differentiate into various specialized blood cells throughout the body.

Immune System

The immune system is responsible for defending the body against pathogens.
It involves both innate (rapid non-specific response) and adaptive(slower specific with immunological memory response).
Innate components: cells (macrophages, granulocytes, lymphocytes, mast cells), and molecules (complement).
Adaptive components: mainly B and T lymphocytes.

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Description

Explore the fascinating world of blood, a specialized connective tissue essential for transporting nutrients, waste products, and gases throughout the body. This quiz covers the components of blood, including the crucial role of plasma, which constitutes a significant volume of blood and is vital for maintaining osmotic balance and temperature regulation.