Plasma Proteins and Erythrocytes Quiz

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Questions and Answers

What is the role of Vitamin B12 in the body?

Production of white blood cells

Absorption of calcium

Synthesis of RNA

Synthesis of DNA (correct)

Which type of anemia is associated with Vitamin B12 deficiency?

Sideroblastic anemia

Macrocytic anemia (correct)

Microcytic anemia

Normocytic anemia

Where is Vitamin B12 absorbed in the body?

Colon

Upper small intestine (duodenum)

Stomach

Lower small intestine (ileum) (correct)

Which of the following conditions is caused by iron deficiency?

Microcytic anemia Signup and view all the answers

What stimulates the release of erythropoietin (EPO) from the kidneys and liver?

Hypoxia Signup and view all the answers

Which organ is primarily responsible for forming 85% of erythropoietin?

Kidney Signup and view all the answers

What is a common cause of folic acid deficiency?

Deficient diet Signup and view all the answers

What is a typical consequence of chronic hemorrhage?

Microcytic anemia Signup and view all the answers

Which hormone is NOT involved in stimulating erythropoiesis?

Insulin Signup and view all the answers

What is a common cause of anemia in patients with chronic kidney disease (CKD)?

Decreased erythropoietin production Signup and view all the answers

Which of the following is true regarding the absorption of iron?

It requires gastric HCl and Vitamin C for absorption. Signup and view all the answers

Which of the following statements about erythrocytes is correct?

They are flexible biconcave cells. Signup and view all the answers

What type of anemia is characterized by normal size and shape of red blood cells?

Normocytic anemia Signup and view all the answers

Which substance is crucial for the absorption of vitamin B12?

Intrinsic factor Signup and view all the answers

What condition does not inhibit erythropoiesis?

Adequate oxygen levels Signup and view all the answers

In which anatomical location does erythropoiesis mainly occur after the first 5 years of life?

Bone marrow of all bones Signup and view all the answers

Which plasma proteins are primarily synthesized by the liver?

Albumin, globulins, and 50% of fibrinogen Signup and view all the answers

What is the main function of albumin in plasma?

Regulation of osmotic pressure Signup and view all the answers

What is the primary site of erythropoiesis in adults?

Flat bones and axial skeleton Signup and view all the answers

Which statement is incorrect regarding plasma proteins?

Albumin is mainly formed by reticulo-endothelial system. Signup and view all the answers

What factor primarily stimulates erythropoiesis?

Oxygen supply and erythropoietin Signup and view all the answers

What is the lifespan of red blood cells (RBCs)?

120 days Signup and view all the answers

What property of red blood cells allows for increased surface area and flexibility?

Biconcave shape Signup and view all the answers

Which plasma protein has the lowest molecular weight?

Albumin Signup and view all the answers

What is the primary source of platelets in the body?

Bone marrow Signup and view all the answers

What is the order of steps in the hemostasis process?

Vasoconstriction, Platelet plug, Clotting Signup and view all the answers

Which of the following is NOT a step needed for platelet plug formation?

Adhesion to normal endothelium Signup and view all the answers

What vitamin is necessary for the synthesis of certain clotting factors?

Vitamin K Signup and view all the answers

Which anticoagulant is derived from mast cells and basophils?

Heparin Signup and view all the answers

What is the primary difference between the intrinsic and extrinsic pathways of clotting?

One is rapid while the other is slow Signup and view all the answers

Which of the following is an example of an in vitro anticoagulant?

Heparin Signup and view all the answers

What characteristic does prostacyclin (PGI2) have regarding platelet reactions?

It inhibits platelet reactions Signup and view all the answers

Study Notes

Plasma Proteins

Synthesis
- Liver produces albumin, globulins, and 50% of fibrinogen
- Gamma globulins are formed by plasma cells
Functions
- Include clotting factors
- Globulins are mainly formed in the liver
- Albumin has the lowest molecular weight
- Prevent the loss of iron and vitamin B12 in urine
- Are sources of tissue proteins
Deficiency
- Produces edema
- Can be caused by liver or kidney disease

Red Blood Cells (Erythrocytes)

Characteristics
- No nuclei or mitochondria
- Biconcave shape for increased surface area and flexibility
- Males: 5.4 million/mm3
- Females: 4.8 million/mm3
Lifespan and Fate
- 120 days
- Site of Hemolysis: Spleen
- Iron is stored as ferritin
Factors Affecting Erythropoiesis
- Oxygen supply and erythropoietin (EPO)
- Healthy organs: bone marrow, liver, kidney
- Hormones & Diet

Erythropoiesis

Definition
- Formation of new red blood cells
Site
- Fetus: liver & spleen
- Children: red marrow of all bones
- Adults: flat and axial bones (vertebrae, skull, ribs, clavicle, scapula, and pelvis)
Factors Affecting Erythropoiesis
- Oxygen supply & erythropoietin (EPO)
  - Hypoxia (high altitudes, athletes, newborns, hemorrhage, lung & heart diseases) stimulates EPO release from kidney and liver, leading to increased erythropoiesis.
- Healthy organs: bone marrow, liver, kidney
  - Bone marrow destruction or depression (X-ray, irradiation, toxins, infections, malignancy) can lead to aplastic anemia.
  - Liver produces 15% of EPO and participates in globin protein synthesis.
  - Kidney forms 85% of EPO and stores Iron and Vitamin B12.
- Hormones & Diet
  - Hormones: erythropoietin, thyroxin, androgens, glucocorticoids
  - Diet: proteins, iron, vitamins (C, B12, folic acid), and trace elements (copper, zinc, cobalt, selenium)

Iron Absorption

Process
- Ferric (Fe+3) is converted to ferrous (Fe+2) by HCl in the enterocytes of the upper small intestine.

Vitamin B12 (Cyanocobalamin, Maturation Factor, Extrinsic Factor)

Sources
- Animal products
Absorption
- Requires intrinsic factor from the stomach
- Occurs in the lower ileum
- Stored in the liver
Deficiency
- Causes: Failure of absorption, dietary deficiency (vegetarians)
- Leads to: Macrocytic anemia and neurological manifestations
Importance
- Synthesis of DNA
- Myelination of nerves

Folate Acid (Folic Acid)

Sources
- Fresh food
Deficiency
- Causes: Deficient diet, pregnancy, malabsorption, antifolate cytotoxic drugs
- Leads to: Macrocytic anemia

Types of Anemia

Microcytic Hypochromic Anemia
- Iron deficiency anemia
- Causes: Decreased dietary intake, increased demand (pregnancy & children), decreased absorption
Normocytic Normochromic Anemia
- Causes: Acute blood loss (hemorrhage), hemolysis, aplastic anemia
Macrocytic (Megaloblastic) Anemia
- Causes: Vitamin B12 deficiency (gastrectomy, absence of intrinsic factor, pernicious anemia, distal small intestine diseases), folate deficiency (deficient diet, pregnancy, malabsorption, antifolate cytotoxic drugs).

Hemolytic Anemia

Intrinsic Disorders
- Hereditary spherocytosis
- Sickle cell anemia (Hb S)
- G-6-PD enzyme deficiency (Favism)
- Thalassemia
Extrinsic Disorders
- Incompatible blood transfusion
- Erythroblastosis fetalis (Rh incompatibility)
- Bacterial toxins, chemicals, or poisons
- Drugs

Hemolytic Jaundice

Occurs due to the breakdown of red blood cells.

Platelets (Thrombocytes)

Characteristics
- Small, non-nucleated, granulated bodies
- 300,000/mm3
- Thrombocytopenia (low platelet count) and thrombocytosis (high platelet count)
- Source: Bone marrow

Hemostasis

Definition
- The process of stopping bleeding from an injured blood vessel.
Steps
- Vasoconstriction
- Platelet plug formation
- Clotting (fibrin threads)

Platelet Plug Formation

Mechanism
- Platelets adhere to injured endothelium, becoming activated.

Blood Clotting

Clotting Factors
- Inactive plasma proteins synthesized in the liver.
- Some require vitamin K.
Mechanisms
- Intrinsic pathway (slow, 1-6 minutes, vivo & vitro)
  - Factors VIII, IX, XI, XII, Ca++
- Extrinsic pathway (rapid, 15 seconds, vivo only)
  - Factors III, VII, Ca++
- Both pathways activate factor X, leading to thrombin and fibrin formation.

Anticlotting Mechanisms

General Factors
- Smooth endothelium
- Rapid blood flow
- Heparin
Specific Factors
- Prostacyclin (PGI2): secreted from normal endothelium, decreases platelet reactions.
- Antithrombin III: Inhibits factors 9, 10, 11, 12. Facilitated by heparin.
- Fibrinolysis: Breakdown of fibrin by plasmin and other proteins.

In Vitro Anticoagulants

Mechanism
- Inhibit coagulation by removing or inactivating calcium ions.
Examples
- Sodium citrate
- Sodium oxalate
- Silicon tubes
- Heparin
- EDTA

In Vivo Anticoagulants

Heparin
- Origin: Mast cells and basophils
- Action: Helps antithrombin III to inactivate clotting factors, especially thrombin.
- Site of action: Both in vivo and in vitro.
Dicumarol
- Origin: Plants
- Action: Competitively inhibits vitamin K.
- Site of action: Only in vivo.

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Description

Test your knowledge on plasma proteins, their synthesis, functions, and deficiencies, as well as the characteristics and lifespan of red blood cells. This quiz also explores the process of erythropoiesis and various factors influencing it. Perfect for students studying human physiology.