BMS107 - Final exam

Question 1

Define and be prepared to label the components of centrifuged blood.

Answer 1

The components of centrifuged blood are:

• Red blood cells (erythrocytes) – 45%
• Buffy Coat with White blood cells and platelets (leukocytes) – less than 1%
• Blood plasma – 55%

Question 2

What are erythrocytes and why are they referred to as formed elements?

Answer 2

Erythrocytes are red blood cells that are biconcave in form and carry oxygen/carbon-dioxide and nutrients to the various tissues in the body. They are referred to as formed elements due to their non-fluid state along with leukocytes and platelets (thrombocytes).

Question 3

What is the composition of plasma? How much water? How much protein and what types? Other substances?

Answer 3

Composition of plasma:

• 92% water
• Consists of the proteins (7%):
  
  • Albumin – 58%
  • Globulin – 37%
  • Fibrinogen – 4%
  • Regulatory proteins – 1%
  • Others – 1% (nutrients, wastes, respiratory gases)

Question 4

What are the general functions of blood?

Answer 4

General functions of blood:

• Transports respiratory gases (O2/CO2)
• Transports nutrients and wastes
• Regulates fluid volume, PH-level and temperature
• Mounts immune system and antibody production

Question 5

What is the structure of a RBC?
Why?

Answer 5

Red Blood Cell structure:

An erythrocyte or “red blood cell” is a biconcave (to increase cross section area) cell without a nucleus or organelles. It cannot undergo mitosis. About 7.5 micrometer in diameter.

Question 6

What is the function of hemoglobin and how many molecules of oxygen/carbon dioxide can each molecule bind to?

How many hemoglobin molecules/RBC?

Answer 6

Function of Hemoglobin:

Hemoglobin is abundant in RBCs and is responsible for the binding of O2 and CO2. They can reversibly bind 4 molecules of oxygen or 4 molecules of carbon-dioxide, but never a mix of both. There are about 280 million hemoglobin molecules per erythrocyte.

Question 7

Describe the process of erythropoiesis – what is the stimulus for this production and how can it be used illegally (e.g., ‘Blood Doping’). How might blood doping affect physiology positively/negatively?

Answer 7

Process of erythropoiesis:

Erythropoiesis is the creation of new red blood cells. It occurs in red bone marrow. A red blood cell has the life cycle of 120 days before they are recycled. 3 million new RBCs are created every second, or 2 billion every day. Erythropoiesis is stimulated by low oxygen in the blood which is detected by the kidneys. The kidneys then release Erythropoietin (EPO) which tells the red bone marrow to create more erythrocytes.

This is sometimes facilitated by endurance athletes who need more red blood cells to perform better, by using pressure chambers to simulate high altitude. Blood doping can potentially be dangerous due to the abundance of RBCs and cause hyperviscosity. This increases the risks of heart attack, stroke and pulmonary embolism.

Question 8

Define and be able to draw the various classifications of leukocytes. What is their prevalence compared to RBCs?

Answer 8

Classifications of leukocytes:

Leukocytes can be classified into granulocytes and agranulocytes.

Neutrophils (G) – 50-70% - phagocytes that are active in early inflammation “neutralizes”

Lymphocytes (A) – 20-40% - Has B, T, and natural killer cells

Monocytes (A) – 2-8% - Reach infection later, but come in large numbers. Has small granules.

Eosinophils (G) – 1-4% - Release enzymes that fight histamine and other mediators in allergic reactions.

Basophils (G) – 0.5-1% - Least common. Release heparin, histamine and serotonin which intensifies allergic reactions.

Leukocytes are very much less abundant compared to RBCs in the blood. They are a part of the < 1% Buffy coat together with platelets, and increase in numbers during infection. They are 1.5 – 3x as large as erythrocytes.