Blood, Blood Vessels and the Lymphatic System

Question 1

What is the definition of blood?

Answer 1

A highly specialised, complex, mobile connective tissue in which living blood cells are suspended in a fluid called plasma

Question 2

What is the pH of blood?

Answer 2

7.35-7.45

Question 3

What is the average volume of blood in males and females?

Answer 3

Male- 5-6 litres

Female- 4-5 litres

Question 4

Name the 3 functions of blood

Answer 4

Transportation, protection and regulation

Question 5

What is transported in the blood?

Answer 5

Oxygen from lungs, carbon dioxide from cells (diffusion)
Nutrients from the gastrointestinal system to cells (GI)
Heat and waste products away from cells
Hormones from the endocrine system to other cells

Question 6

What are the protective factors of the blood?

Answer 6

Blood clotting in response to injury, prevents blood loss

Contains proteins to protect against disease

Question 7

What does the blood regulate?

Answer 7

pH of body fluids
Temperature regulation
Osmotic pressure

Question 8

What are the main components of blood?

Answer 8

55% plasma, 45% red blood cells, <1% white blood cells and platelets

Question 9

Describe the properties of plasma?

Answer 9

Straw coloured liquid consisting of 91.5% water
7% plasma proteins-
Albumins help to maintain osmotic pressure
Globulins include antibodies (immunoglobulin’s)
Fibrinogen for formation of blood clots
1.5% other solutes such as electrolytes, nutrients, gases, enzymes, hormones, vitamins and waste products

Question 10

What is Haematopoiesis?

Answer 10

The formation of blood cells. Occurs in red bone marrow. All blood cells are derived from a common stem cell (haemocytoblast.)

Question 11

Name the Haemocytoblast differentiations

Answer 11

Lymphoid stem cell produces lymphocytes

Myeloid stem cell produces all other formed elements

Question 12

How are red blood cells (erythrocytes) formed?

Answer 12

Erythropoiesis
Made in the red bone marrow in bones of pelvis, ribs, breastbone, backbones, skill and ends of long bones of arms and legs

Question 13

What is the life span of a red blood cell?

Answer 13

120 days

Worn out blood cells are destroyed in spleen, liver and red bone marrow, phagocytosed by macrophages

Question 14

What is the structure of red blood cells?

Answer 14

Bioconcave in shape
Contains oxygen-carrying protein haemoglobin (Hb), which consists of the protein globin and iron containing red pigment heme (haem)
Hb transports most of the oxygen and some of the carbon dioxide in blood

Question 15

What is the function of the white blood cells (leukocytes)?

Answer 15

Combat pathogens and foreign substances that enter the body
Most only live a few days or hours during response to infection
Some leukocytes give us immunity, these cells can last for years (Memory T&B lymphocytes)

Question 16

What are the 2 major groups of leukocytes?

Answer 16

Granulocytes (neutrophils, eosinophils, and basophils)

Agranulocytes (lymphocytes and monocytes)

Question 17

Describe the properties and function of platelets (thrombocytes)?

Answer 17

Cell fragments which are disc shaped and have no nucleus

When blood vessels are damaged, the platelets form a platelet plug

Question 18

Define haemostasis

Answer 18

A sequence of responses: stops bleeding when blood vessels are injured

Question 19

What are the three stages of haemostasis?

Answer 19

1. Vasospasm- smooth muscle in the wall of damaged blood vessel contracts immediately. Platelets release chemicals which enhance the vasospasm. Reduces blood loss for the vessel for minutes to hours
2. Platelet plug formation- platelets come in contact and stick to the damaged vessel, they release chemicals increasing vasospasm and other platelets are made sticky. Platelets form a mass called a platelet plug
3. Blood clotting- various chemicals (clotting factors) activate each other and result in the formation of fibrin threads in which the formed elements of blood are trapped

Question 20

What are the stages of clotting?

Answer 20

Prothrombinase converts to prothrombin into thrombin which converts fibrinogen into fibrin

Question 21

What are antigens (agglutinogens)?

Answer 21

Glycoproteins and glycolipids found on the surface of erythrocytes which are genetically determined

Question 22

How are blood groups determined?

Answer 22

Based on presence or absence of various antigens. There may be two or more blood types in a blood group

Question 23

What are the different blood groups?

Answer 23

If red blood cells have-
Only antigen A= type A blood
Only antigen B= type B blood 
Both A and B= type AB 
Neither A nor B= type O blood

Question 24

What is the Rhesus (RH) Blood Group?

Answer 24

An antigen that was discovered in the blood of rhesus monkeys. People are either Rh positive or negative.
If red blood cells have Rh antigens= Rh positive
If red blood cells to not contain antigens= Rh negative

Question 25

What happens if you give an Rh- patient Rh+ blood?

Answer 25

anti-Rh antibodies are formed. If another transfusion is given, anti-Rh antibodies will haemolyse (rupture) red blood cells of donated blood

Question 26

What are arteries?

Answer 26

Blood vessels carry blood away from the heart

Question 27

What are veins?

Answer 27

Blood vessels that carry blood towards the heart

Question 28

What are capillaries?

Answer 28

Tiny blood vessels that create a network enabling diffusion of gasses and solutes

Question 29

Why do arteries have thick walls?

Answer 29

To withstand blood which is sometimes exerting at a high pressure

Question 30

Describe the properties of arteries

Answer 30

Elastic as they have to expand and recoil as blood pulses through. There is high blood pressure when ventricles contract and blood squeezed out, less pressure during diastole

Question 31

What are the layers in the arteries?

Answer 31

Tunica adventitia- outer layer made of elastic fibres and collagen Tunica media- thickest layer, mostly smooth muscle with elastic fibres Tunica intima- inner layer, endothelium lining forms a smooth lining which is in contact with blood

Question 32

What are arterioles?

Answer 32

Very small arteries that deliver blood to the capillary beds. The walls are the same 3 layers as in arteries

Question 33

What is the function of arterioles?

Answer 33

Have a key role in regulating blood flow to different organs - For example, during emergency situations such as blood loss, they can constrict which reduces blood flow to some less essential areas such as the skin (skin becomes pale) and gastrointestinal tract - More blood is then available for essential organs such as the heart, lungs, brain and skeletal muscle (stress response often known as fight or flight)

Question 34

What is the pulse?

Answer 34

A wave or pulse of blood due to expansion of the artery during ventricular contraction (systole). The pulse can be felt where the artery flows close to the body surface

Question 35

Describe the walls of the veins

Answer 35

Same as in arteries and arterioles but blood in veins exert very little pressure, so size differs from arteries. Tunica adventitia- thicker than in arteries Tunica media- thinner than in arteries Tunica intima- thinner than in arteries

Question 36

Describe the structure of veins

Answer 36

Contain semi-lunar valves which prevent backflow of blood. These are made from folds of tunica intima

Question 37

What are venules?

Answer 37

Very small veins. Blood flows from arteries into capillaries then into venules then veins which carry blood back to the heart

Question 38

Describe the properties of capillaries

Answer 38

- Microscopic blood vessels - 1 cell thick wall, endothelium is supported on a basement membrane - Exchange vessels- the only blood vessels through which nutrients, gasses, waste from tissues etc can enter or leave the blood - Almost all cells have a capillary close to them - An arteriole breaks down into a series of capillaries known as a capillary bed

Question 39

What is the lymphatic system?

Answer 39

A system of vessels that carry fluid from the tissues, cleans it and puts it into the blood stream

Question 40

What do lymphatic capillaries do?

Answer 40

Drain excess fluid from the tissues

Question 41

What happens in the lymph nodes?

Answer 41

Fluid flows through and microbes are filtered out and dealt with by immune system. Many cells of immune system in lymph nodes.