Lecture 4 - Cardiovascular system and respiration

Question 1

What are the functions of blood?

Answer 1

1. Transportation - oxygen, nutrients, wastes, carbon dioxide and hormones
2. Defence - Against invasion by pathogens
3. Regulatory functions - body temperature, water-salt balance and body pH

Question 2

What is the composition of blood?

Answer 2

1. Blood is a fluid connective tissue
2. Formed elements : produced in red bone marrow
   - Red blood cells/erythrocytes (RBC)
   - White blood cells/leukocytes (WBC)
   - Platelets

Plasma:
91% water and 9% salt (ions) and organic molecules
Plasma proteins are the most abundant molecules

Question 3

Structure of red blood cells?

Answer 3

1. Lack a nucleus and few organelles
2. Biconcave shape increases surface area
3. Contain about 280 million haemoglobin molecules that bind FOUR molecules of O2 each

Question 4

Production of red blood cells

Answer 4

1. Produced in the red bone marrow
2. Lifespan of about 120 days
3. Erthyopoietin (EPO) is excreted by kidney cells and moves to red marrow when oxygen levels are low
4. Old cells are destroyed by the liver and spleen

Question 5

Properties of white blood cells?

Answer 5

1. Derived from red bone marrow
2. Large blood cells that have a nucleus
3. Production is regulated by colony-stimulating factor (CSF)
4. Can be found in the blood as well as in tissues
5. Fight infection and an important part of the immune system
6. Some live days and other live months of years

Question 6

How are white blood cells categorised?

Answer 6

1. Granular - contain noticeable granules, lobed nuclei
   - Eosinophil
   - Basophil
   - Neutrophil
2. Agranular - no granules, nonlobed nuclei
   - Lymphocyte
   - Monocyte

Question 7

Properties of platelets?

Answer 7

1. Made of fragments of large cells called megakaryocytes made in the red bone marrow