Blood And Blood Diseases

Question 1

Describe the functions of blood

Answer 1

• Deliver 02
• Remove metabolic waste
• Maintain temperature, pH, and fluid volume
• Protection from blood loss-platelets
• prevent infection -antibodies and white blood cells
• Transport hormones

Question 2

Describe the components of blood

Answer 2

• blood plasma components-55%
• 90% water
• 80% solutes:
  proteins: albumin (60%)- helps maintain blood pressure, alpha and beta globulins, gamma globulins’ fibrinogens
• gas
• electrolytes (sodium, potassium, carb)

-Organic nutrients
Carbohydrates, amino acids, lipids, vitamins

-hormones

• metabolic waste
  CO 2,urea

Formed elements of the blood:
erythrocytes (red blood cells)
Leukocytes (White blood cells)
Platelets (thrombocytes)

Haematopoiesis-blood cell formation occurs in red bone marrow of axial skeleton, girdles and proximal epiphyses of humerus and femur

Question 3

Relate the structure ofbbood components to their function

Answer 3

A

Question 4

Explain how red blood cells are made and destroyed

Answer 4

Haematopoiesis: blood cell formation
Haemocytoblast: naematopoietic stem cells
Erythropoiesis: red blood cell production

v
Phases in development
1. Ribosome synthesis
2. Hemoglobin accumulation
3 ejection of the nucleus and formation of reticulacytes
-Reticulocytes then become mature erythrocytes

Stem cell> committed cell> (developmental pathway) phase 1 ribosome synthesis> P2 hemoglobin accumulation> P3 ejection of nucleus

Hemocytoblast.            Stem cell
Proerythroblast             committed cell
Early erythroblast
Late erythroblast
Normoblast
Reticulocyte
Erythrocyte

• hemopoiesis of erythrocytes begins in hemopoietic bone marrow hence stem cell>erythroblast>reticulocyte
• reticulocytes are released into the bloodstream, where they mature into erythrocytes, which circulate for an average of 120 days
  And then….
  FORMATION AND DESTIRUCTION

3. Old damaged erythrocytes are phagocytized by macrophages in the bone marrow, liver and spleen
4. The globin portion of hemoglobin
5. Metabolised into amino acids which are reused for protein synthesis (cell components are also recycled
6. The heme portion is broken into Bilverdin for transport in the blood
7. The iron ions bind to the blood protein transferrin for
8. For transport
9. Unused heme group can be recycled and used in hemopoisis, or can be converted into bilirubin and used to make bile in the liver.
10. Iron ions can also be transferred to the protein ferritin for storage in the liver

Question 5

Describe the major diseases that affect red and white blood cells

Answer 5

Anaemia
-when blood has low O2 capacity; insufficient RBC or iron deficiency. Factors that can cause anemia; exercise, B12 deficiency

RED BLOOD CELL DISEASES
Sickle cell anaemia
-(more a structure based protein) Hbs results from a change in just one of the 287 amino acids in the chain in the globin molecule.
- Found in 1 out of 400 African Americans
- Homozygous for sickle-cell is deadly, but in malaria infested countries, the heterozygous condition is beneficial

Polycythemia

• excess of erythrocytes, viscosity of blood. 8-11 million cells/mm3
• usually caused by cancer; however naturally occurs at high elevations

Blood doping
- in athletes remove blood 2 days before event and then replace it- banned by Olympics

WHITE BLOOD CELL DISEASES
Leukopenia
- Abnormally low WBC-drug induced

Leukaemias

• cancerous conditions involving WBCs
• Named according to the abnormal WBC clone involved

Mononucleosis
- highly contagious viral disease caused by Epistein- Barr virus; excessive of agranulocytes, fatigue, sore throat, recover in a few weeks

Question 6

Recognise the diagnostic symptoms of anaemia

Answer 6

Mouth and nose ulcers

SKIN; butterfly and red patches

HEART: endocarditis, atherosclerosis, inflammation of the fibrous sac

Severe abdominal pain

BLOOD: anemia, high blood pressure

MUSCLE AND JOINTS: pain and arthritisaches

LUNGS: pleuritic, pneumonitis, pulmonary emboli, pulmonary haemorrhage

KIDNEYS: blood in urine

Hair loss, higher fever, abnormal, headache

Question 7

Describe th’e function of platelets, common clotting disorders and how the treat them

Answer 7

• small fragments of megakaryocytes
• formation is regulated by thromobopoietin (clotting)

Hemocytoblast (stem cell)
Megakaryoblast (development pathway)
Promegrakaryocyt (^)
Megakaryocyte (^)
Platelets

Haemostasis :

1. Vessel injury
2. Vascular spasm
3. Platelet plug formation
4. Coagulation

DISORDERS OF HAEMOSTASIS:

• Thromboembolytic disorders: undesirable clot formation
• Bleeding disorders: abnormalities that prevent normal clot formation

THROMBOEMBOLYTIC CONDITIONS

• Thrombus: a clot that develops and persists in an unbroken blood vessel… may block circulation, leading to tissue death
• Embolus: a Thrombus freely floating in the blood stream…. Pulmonary emboli impair the ability of the body to obtain oxygen, cerebral emboli can cause strokes

PREVENTED BY:

• Aspirin : antiprostaglandin that inhibits thromboxane A2
• Heparin : anticoagulant used clinically for pre and postoperative cardiac care
• Warfarin: used for those prone to atrial fibrillation

BLEEDING DISORDERS

• Thrombocytosis - too many platelets due to inflammation, infection or cancer
• Thrombocytopenia- two few platelets , causes spontaneous bleeding, due to suppression or destruction of bone marrow, platelet count <50,000/mm3 is diagnostic, treated with transfusion of concentrated platelets

Question 8

Describe the ABO and Rhesus blood group systems

Answer 8

A

Question 9

Describe grouping cross-matching and typing with anti-sera

Answer 9

A