NTA Level 4 • Semester 1 • PST04103

Common Disorders of Blood Cells

Human Anatomy and Physiology • Source Session/Topic 19

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Session 19: Common Disorders of Blood Cells

Total Session Time: 60 minutes + 60 minutes assignment

Prerequisites

• Session 14, Blood grouping and ABO system

Learning Tasks

By the end of this session students are expected to be able to:

• Define the Term Blood Cell Disorder

• Explain the Common Disorders of the Blood Cells

• Explain Thrombosis and Embolism

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board, chalk and whiteboard markers

• Computer

• Projector

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing

STEP 2: Definition of Blood Cell Disorder (5 minutes)

|Activity: Brainstorming (5 minutes) |

| |

|Ask students to brainstorm on the following question: |

| |

|What is a blood cell disorder? |

| |

|ALLOW few students to respond |

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|WRITE their responses on the flip chart/ board |

| |

|CLARIFY and SUMMARISE by using the content below |

• Blood cell disorder is a disorder which affects the red blood cells,

white blood cells and smaller circulating cells called platelets

STEP 3: Common Disorders of the Blood Cells (20 minutes)

|Activity: Small Group Discussion ( 15 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|What are the common blood cells disorders? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

Classification of Common Disorders of the Blood Cells

• Anaemia

o Iron-deficiency anaemia

o Sickle-cell disease (anaemia)

o Aplastic anaemia

o Haemolytic anaemia

• Haemophilia

• Leukaemia

• Vitamin K deficiency

Anaemia

• Anaemia is a deficiency of red blood cells, or insufficient haemoglobin

within the red blood cells.

• There are many different types of anaemia.

o Iron-deficiency anaemia

▪ It is caused by a lack of dietary iron, and there is not enough of

this mineral to form sufficient haemoglobin.

▪ A person with this type of anaemia may have a normal RBC count and a

normal haematocrit, but the haemoglobin level will be below normal.

▪ A deficiency of vitamin B12, which is found only in animal foods,

leads to pernicious anaemia, in which the RBCs are large, misshapen,

and fragile.

▪ Another cause of this form of anaemia is lack of the intrinsic

factor due to autoimmune destruction of the parietal cells of the

stomach lining.

o Sickle-cell disease (anaemia)

▪ It is a genetic disorder of haemoglobin (Hb-S), which causes RBCs

to sickle, clog capillaries, and rupture.

▪ Even though erythropoiesis is stimulated by the loss of the cells,

it cannot keep pace with haemolysis.

o Aplastic anaemia

▪ It is suppression of the red bone marrow, with decreased production

of RBCs, WBCs, and platelets.

▪ This is a very serious disorder that may be caused by exposure to

radiation, certain chemicals such as benzene, or some medications.

o Haemolytic anaemia

▪ It is any disorder that causes rupture of RBCs before the end of

their normal life span.

▪ Sickle-cell anaemia and Rh disease of the new-born are examples.

▪ Another example is malaria, in which a protozoan parasite reproduces

in RBCs and destroys them.

▪ Haemolytic anaemias are often characterized by jaundice because of

the increased production of bilirubin.

Haemophilia

• Haemophilia is an inherited deficiency of clotting in which bleeding may

occur spontaneously or after only minor trauma.

• It is the oldest known hereditary bleeding disorder

• Different types of haemophilia are due to deficiencies of different blood

clotting factors and exhibit varying degrees of severity, ranging from

mild to severe bleeding tendencies

Leukaemia

• The term leukaemia refers to a group of red bone marrow cancers in which

abnormal white blood cells multiply uncontrollably

• The accumulation of the cancerous white blood cells in red bone marrow

interferes with the production of red blood cells, white blood cells, and

platelets

• As a result the oxygen-carrying capacity of the blood is reduced, an

individual is more susceptible to infection, and blood clotting is

abnormal

• The cause of most types of leukaemia is unknown

Vitamin K deficiency

• Vitamin K is not involved in actual clot formation but it is required for

the synthesis of four clotting factors.

• It is a fat-soluble vitamin that can be absorbed through the lining of

the intestine and into the blood if absorption of lipids is normal

• People suffering from disorders that slow absorption of lipids (for

example, inadequate release of bile into the small intestine) often

experience uncontrolled bleeding as a consequence of vitamin K deficiency

STEP 4: Thrombosis and Embolism (10 minutes)

Thrombosis

• It is the formation of a clot in the blood that either blocks, or

partially blocks a blood vessel.

• The thrombus may lead to infarction, or death of tissue, due to a blocked

blood supply.

• The pathologic form of haemostasis is thrombosis. It involves blood clot

(thrombus) formation in uninjured vessels or thrombotic occlusion of a

vessel after relatively minor injury.

• Both haemostasis and thrombosis involve three components, the vascular

wall, platelets, and the coagulation cascade.

o Age (as the age increases so the risk)

o Obesity

o Varicose veins

o Immobility

o Pregnancy

o High estrogenic levels

o Previous history of DVT

o Surgery and trauma of the pelvis, lower limbs

o Heart failure

o Recent myocardial infarction

o Lower limb paralysis

o Cigarette smoking

Embolism

• An embolism is an obstruction in a blood vessel due to a blood clot or

other foreign matter that gets stuck while travelling through the

bloodstream.

• Emboli have moved from the place where they were formed through the

bloodstream to another part of the body, where they obstruct an artery

and block the flow of blood.

• The emboli are usually formed from blood clots but are occasionally

comprised of air, fat, or tumour tissue.

• Embolic events can be multiple and small, or single and massive.

• They can be life-threatening and require immediate emergency medical care

STEP 5: Key Points (5 minutes)

• Anaemia is a deficiency of red blood cells, or insufficient haemoglobin

within the red blood cells.

• It is divided into iron deficiency anaemia, sickle cell anaemia, aplastic

anaemia and haemolytic anaemia

• Haemophilia is inherited deficiency of clotting factors

STEP 6: Evaluation (5 minutes)

• What is blood cells disorder?

• What is the cause of iron deficiency anaemia?

• What is the consequence of vitamin K deficiency?

Step 7: Assignment (10 minutes)

|Activity: Take Home Assignment (10 minutes) |

| |

|DIVIDE learners in groups or individual. |

| |

|ASK the learners to work on the following assignment |

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|Classify common disorders of the blood cell |

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|ALLOCATE time for learners to do the assignment and submit |

| |

|REFER learners to recommended references |

References

Kumar, A. et al (2004). Robbins Basic Pathology. WB: Saunders.

Spector, T.D. & Axford, J. S. (1999). Introduction to General Pathology.

Edinburgh:

Seeley, R. R., Stephens, T. D.& Tate, P. (2003). Anatomy and Physiology.

New York:

McGraw-Hill

Shier, A., Butler, J., & Lewis, R. (2004). Hole’s Human Anatomy &

Physiology. New York:

McGraw-Hill

Standring, S. (2008). Grays’s Anatomy The anatomical basis of clinical

practice. United

Kingdom: Churchill Livingstone Elservier.

Thibodeau, G. A., & Patton, K. T. (1999). Anatomy & Physiology. Saint

Louis: Mosby,

Von Hoffman Press, Inc.

Tortora, G.J & Derrickson, B (2009).Principles of Anatomy and Physiology

12th Edition,

USA, John Wiley & Sons Inc, USA

Walter, J.B, & Talbot, I. C. (1996). General Pathology. New York: Churchill

Livingstone

Waugh, A. & Grant, A. (2006). Ross and Willson Anatomy and physiology in

Health and

illness. United Kingdom: Churchill Livingstone Elservier

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