Ch.25 - Blood

Question 1

What composes blood?

Answer 1

Blood is made of plasma, red blood cells, white blood cells and platelets.

Question 2

What is plasma?

Answer 2

Plasma is a pale golden liquid that makes up about 55% of the blood. Plasma is made of 90% water, 7% proteins and 3% dissolved materials being transported.

Question 3

What are the main plasma proteins?

Answer 3

The main plasma proteins are antibodies, which are produced by white blood cells in order to combine with and neutralise foreign substances. And clotting proteins which are acted upon to form blood clots. They help ensure that blood plasma has the same concentration as blood cells.

Question 4

What is the role of plasma?

Answer 4

The role of plasma is to transport dissolved materials such as glucose, urea and hormones. Plasma also carries heat.

Question 5

What is serum?

Answer 5

Serum is plasma from which the clotting proteins have been removed.

Question 6

Where are red blood cells produced?

Answer 6

Red blood cells(erythrocytes) are produced in the marrow of bones such as ribs, breastbone and vertebrae of the backbone.

Question 7

What do red blood cells consist of?

Answer 7

Erythrocytes consist of a flexible membrane containing molecules of a red protein called haemoglobin. Iron is essential to haemoglobin.

Question 8

What are the functions of red blood cells?

Answer 8

Red blood cells’ main function is to transport oxygen. The molecules of iron in haemoglobin can join with oxygen in areas of high concentration and release oxygen in areas of low oxygen.

Question 9

What is anaemia?

Answer 9

Anaemia is a lack of haemoglobin. The symptoms of anaemia are pale skin colour and loss of energy.

Question 10

What are white blood cells?

Answer 10

White blood cells(leucocytes) are larger than red blood cells, have no definite shape, have a nucleus, typically live for a few days and are less numerous than red blood cells(1:700). They are made in the bone marrow and some mature in the lymphatic system.

Question 11

What are the roles of white blood cells?

Answer 11

The roles of leucocytes are to defend the body against infection and to fight infection already in the body. The majority of white blood cells engulf invading particles and digest them. The way in which phagocytes eat solid particles is called phagocytosis. Lymphocytes react to invading particles by producing antibodies.

Question 12

What is leukaemia?

Answer 12

Leukaemia is a type of cancer in which white blood cells are produce too rapidly and immaturely. It may cause anaemia, increased risk of infection and reduced ability to clot blood. Leukaemia may be treated by radiation or drugs.

Question 13

What are platelets?

Answer 13

Platelets(thrombocytes) are made in bone marrow from large cells. These large cells break down to produce cell fragments called platelets. Thrombocytes are smaller than erythrocytes.

Question 14

What are the roles of platelets?

Answer 14

The role of platelets are to clot blood. Blood clots have 2 main functions; to reduce the loss of blood(from a wound) and to prevent the entry of micro-organisms.

Question 15

What are haemophiliacs?

Answer 15

Haemophiliacs are unable to produce one or more clotting chemicals. They cannot form blood clots effectively and are susceptible to excessive bleeding.

Question 16

What is thrombosis?

Answer 16

Thrombosis occurs when vessel walls are damaged, a blood clot is formed, which may lead to the blocking of a vessel. Examples include clots in the brain(strokes) and clots in the heart(heart attack).

Question 17

What are the 4 blood groups? Why is this information important?

Answer 17

Depending on the type of chemicals(if any) attached to the cell membrane, red blood cells are split into the groups: A, B, AB or O. This information is important for blood transfusions and it prevents blood from clumping in the recipient.

Question 18

Name any other blood groups.

Answer 18

There are many other types of blood groups, including those that are positive for the Rhesus factor. (If someone with A blood type is positive for the Rhesus factor, they have A+ blood type)

Question 19

Describe red blood cells.

Answer 19

Red blood cells have no mitochondria, no nuclei and a biconcave shape( this gives them a larger surface area over which they can exchange oxygen). Deoxyhaemoglobin is purple and oxyhaemoglobin is bright red.

Question 20

What are 2 types of leucocytes?

Answer 20

There are lymphocytes, which comprise 25% of white blood cells, they are made in the bone marrow and found in the lymphatic system. Their function is to make antibodies. There are also monocytes which comprise 5% of white blood cells, they are formed in bone marrow and have kidney shaped nuclei. They act as macrophages(large phagocytes).

Question 21

Draw a diagram of a monocyte and a lymphocyte.

Answer 21