Blood Composition and Functions

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Questions and Answers

What is the first stage of platelet plug formation?

Platelet adhesion (correct)

Clot retraction

Clot formation

Platelet activation

Which substance is secreted by activated platelets to recruit more platelets?

Fibrin

Thrombin

ADP (correct)

Calcium

What initiates clot retraction after a blood clot has formed?

Retractozyme and contraction of platelets (correct)

Formation of thromboxane A2

Fibrin degradation

Increased blood flow

What forms the mesh within the blood clot?

Insoluble fibrin Signup and view all the answers

Which cells are primarily involved in the repair of a damaged blood vessel after clot formation?

Fibroblasts and smooth muscle cells Signup and view all the answers

What percentage of blood is made up of plasma?

55% Signup and view all the answers

Which of these is NOT a component of blood cells?

Nutrients Signup and view all the answers

Which plasma protein has the highest concentration?

Albumin Signup and view all the answers

Which function is associated with fibrinogen?

Hemostasis Signup and view all the answers

What is the primary function of albumin in blood?

Osmotic pressure regulation Signup and view all the answers

What percentage of plasma is composed of inorganic substances?

0.9% Signup and view all the answers

Which of the following is a function of globulins?

Immune response Signup and view all the answers

Which substance is NOT typically found in plasma?

Red blood cells Signup and view all the answers

What is the primary role of fibrinogen in hemostasis?

Facilitates the formation of blood clots. Signup and view all the answers

Which component is primarily responsible for the osmotic pressure of plasma?

Albumin Signup and view all the answers

What mechanism is NOT involved in the process of hemostasis?

Glucose metabolism Signup and view all the answers

Which of the following describes the role of gamma globulins in the immune system?

Provide passive immunity. Signup and view all the answers

How does a decrease in plasma proteins affect capillary permeability?

Increases capillary permeability. Signup and view all the answers

What substance released by platelets aids in local vasoconstriction during vascular spasm?

Thromboxane A2 Signup and view all the answers

Which of the following functions does NOT involve the role of plasma proteins?

Conversion of fibrinogen to fibrin. Signup and view all the answers

What is the first step in the hemostasis process after a blood vessel injury?

Vascular spasm Signup and view all the answers

Study Notes

Blood - Introduction

Blood is a vital fluid in humans and other animals
Nourishes body organs and tissues
Carries away waste materials

Composition of Blood

Plasma (55%):
- Mostly water (90%)
- Proteins (8%)
  - Albumin (4-4.5 gm%)
  - Globulins (2.5-2.7 gm%)
    - Alpha 1 and 2, beta 1 and 2, and gamma globulins
  - Fibrinogen (200-400 mg%)
  - Prothrombin (10 mg%)
- Organic substances (1.1%)
  - Nutrients (as digested food)
  - Waste products (as urea and cellular waste products)
  - Other constituents (e.g., hormones, vitamins, lipids, and enzymes)
- Inorganic substances (0.9%)
  - Ions like Na+, Cl-, and HCO3-
Cells (45%):
- White blood cells (WBCs, or leukocytes)
- Red blood cells (RBCs, or erythrocytes)
- Platelets (thrombocytes)

Functions of Plasma Proteins

Nutrition: Plasma proteins are used in protein metabolism.
Hemostasis (Blood Clotting): Fibrinogen and prothrombin are essential for the coagulation process.
Blood Viscosity: Fibrinogen and globulins affect viscosity, important for arterial blood pressure maintenance.
Suspension of RBCs: Important for ESR (erythrocyte sedimentation rate) which is dependent on fibrinogen and globulin levels.
Carrier: Plasma proteins transport important elements like hormones, vitamins, and minerals, preventing rapid elimination in urine.
Immunity: Gamma globulins are used to exert passive immunity.
Regulation of capillary permeability: Plasma proteins maintain normal capillary permeability.
Osmotic function: Plasma protein osmotic pressure is important for water reabsorption in capillaries, counteracting capillary filtration pressure. Albumin is the most contributing protein to plasma osmotic pressure.

Hemostasis (Blood Clotting)

Vascular spasm: Injured vessel walls contract to reduce blood loss. This involves local myogenic contraction, local nervous reflexes, and vasoconstrictor substances.
Platelet plug formation: Platelets adhere to injured sites, release substances (e.g., serotonin and thromboxane A2), and aggregate to form a plug.
Clot formation: Fibrinogen is converted to insoluble fibrin, forming a network to trap blood cells .
Clot retraction: Shrinkage of the clot to decrease the damaged vessel lumen, caused by substances like retractozyme and contractile proteins in platelets.
Repair of injured blood vessel: Platelet-derived growth factor (PDGF) stimulates fibroblasts and smooth muscle, leading to the formation of fibrous tissue.

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Description

Explore the essential components and functions of blood in this quiz. Learn about the various elements that make up blood, including plasma, cells, and the roles of plasma proteins. Test your understanding of how blood nourishes the body and aids in waste removal.