Lecture five- blood cells

Question 1

How many litres of blood does the average human have

Answer 1

5litres

Question 2

Brief overview of what blood is made up of

Answer 2

• blood cells (45-55%)
• plasma- blood without cell components
• human plasma proteome (proteins like albumin, immunoglobin and clotting factors)
• serum (plasma without clotting factors and fibrinogen)

Question 3

Separation of blood components. Explain how you would do this and what the sample would look like in the centrifuge tube.

Answer 3

• take sample
• spin it in the centrifuge tube
• the blood will split into two major components
• the lower level= haematocrit composed of blood cells
• upper level= plasma
• small layer between these containing platelets and white blood cells (lymphocytes)

Question 4

What is plasma

Answer 4

blood without the cell components.

Question 5

What can plasma be used for?

Answer 5

As a blood substitute. When blood isn’t available. To increase volume of blood during a surgery or after trauma. This controls bleeding and aids wound healing.

Question 6

Many drugs will bind to ………. proteins. What does this do? How does this explain why less than 1% of drug is active?

Answer 6

bind to plasma proteins which supresses the drug. Only 1% of the drug is unbound and therefore active.

Question 7

What is serum?

Answer 7

Plasma without the clotting factors and fibrinogen.

Question 8

What are some uses of serum?

Answer 8

• extracted from blood to do diagnostic measurements.
• used in cosmetics
• used as growth media for cell culture

Question 9

The three main types of blood cells. Name them

Answer 9

Erythrocytes (red blood cells), Leucocytes (white blood cells) and Platelets.

Question 10

Role of Erythrocytes/ red blood cells

Answer 10

• carry oxygen around the body
• pH buffering of the blood- keep blood within the normal range of 7.2-7.4

Question 11

Describe the structure and shape of Erythrocytes

Answer 11

• no nucleus- cannot grow, divide or form proteins
• contain haemoglobin- O2 binds to this and is carried around the body.
• biconcave shape- high surface area to volume ration. The shape of red blood cells can also distort/fold.

Question 12

What is responsible for a person’s blood type?

Answer 12

The polysaccharides/ proteins on the surface membrane of red blood cells.

Question 13

Name the process which produces red blood cells/ Erythrocytes

Answer 13

• Erythropoiesis.

Question 14

Describe Erythropoiesis

Answer 14

• controlled by the hormone erythropoietin.
• EPO is secreted in small amounts by the kidney.
• If O2 levels are low, EPO production is triggered.
• More EPO= more red blood cells = more O2 can be carried around the body

Question 15

Reasons for low O2 levels=

Answer 15

• high altitude
• lung disease- insufficient gas exchange
• insufficient pumping of heart
• Anaemia = decrease in the number of erythrocytes/ decreased concentration of haemoglobin per erythrocyte. This can be caused by low iron/B12 and genetic disorders like sickle cell anaemia.

Question 16

What are platelets

Answer 16

• cell fragments with no nucleus
• involved in blood clotting
• derived from megakaryocytes
• production of platelets is controlled by thrombopoietin hormone produced by the liver.

Question 17

Explain how thrombopoietin hormone controls platelet production

Answer 17

• protein binds to the platelet.
• if the platelet counts are normal, the TBO will bind to lots of platelets so the free TPO levels are low
• BUT if the platelet count is low then free TPO levels will be high in the serum as less are bound to platelets.
• High TPO level= platelet production is stimulated.

Question 18

Give some disorders related to platelets

Answer 18

low platelet count causes excessive bleeding
antiplatelet drugs reduce risk of clotting and are used to treat patients with DVT, ischaemic stroke and heart attack.

Question 19

Role of Leucocytes/ white blood cells

Answer 19

Important for the immune response- they are the host defence.

Question 20

What is bone marrow? What comes from bone marrow?

Answer 20

Bone marrow is a spongy tissue found in the centre of bones. Blood cells come from bone marrow.

Question 21

Bone marrow exists in two forms. Give them.

Answer 21

red marrow which contains blood cells AND yellow marrow containing cartilage, fat and bone cells.

Question 22

What else does bone marrow contain that is important for healthy bones and joints?

Answer 22

collagen and glucosamine

Question 23

In children the bone marrow from which bones generates blood cells?

Answer 23

most bones

Question 24

In adults, the bone marrow from which bones generates blood cells?

Answer 24

bones of chest, base of skull, spinal vertebrae and upper sections of limbs.

Question 25

Blood cells are derived from what stem cells?

Answer 25

hematopoietic stem cells

Question 26

Haemopoietic stem cells differentiate into what two cells

Answer 26

myeloid progenitor cells or lymphoid progenitor cells (lymphocytes)

Question 27

Myeloid progenitor cells differentiate into what 6 cells

Answer 27

- Megakaryocyte- which produces platelets. - Eosinophil Basophil Erythrocytes Monocytes- differentiate into dendritic/ macrophages Neutrophil

Question 28

Lymphoid progenitor cells differentiate into three types of cells

Answer 28

- T cell - B cell - differentiate into plasma cells - NK/ T killer cells

Question 29

What happens if you have damaged bone marrow?

Answer 29

anaemic, susceptible to opportunistic infections due to weakened immune system, trouble clotting.

Question 30

How may bone marrow be damaged?

Answer 30

radiation- eg. chemotherapy.

Question 31

How can damage from chemo be prevented? if this doesn't happen how can a patient get more bone marrow?

Answer 31

Sample of bone marrow is taken, the chemotherapy is given, the bone marrow is put back again. The bone marrow will therefore begin to regenerate. If this hasn’t happened, someone will receive bone marrow from a transplant.

Question 32

Key functions of the blood (3 key functions)

Answer 32

- Transport= oxygen, carbon dioxide, nutrients and excretory products (taken to kidney) - Regulation= delivery of hormones to target sites, diversion of blood in body homeostasis and temperature regulation. Eg. take blood to surface of skin to lose heat and maintain homeostasis, for example. - Protection – leukocytes in infection, clotting mechanisms to prevent blood loss.

Question 33

Leucocytes are involved in host immunity. What are the two different types and which white blood cells are involved in each?

Answer 33

1. Innate immunity- myeloid cells. First line of defence against pathogens 2. Adaptive immunity- lymphocytes. Highly specific to the pathogen (antigen specific). Longer lasting protection.

Question 34

Monocytes/ macrophages and neutrophils come from myeloid cells. What is their role?

Answer 34

- phagocytic cells- they engulf protein. - involved in innate immunity.

Question 35

Eosinophils are a a product of ........ cells differentiating

Answer 35

myeloid cells

Question 36

Eosinophil role

Answer 36

defence against parasitic infections. Key mediators in asthma.

Question 37

Basophil cells are also a product of .......... cells differentiating

Answer 37

myeloid

Question 38

what are basophil cells?

Answer 38

- they are circulating immune cells containing histamine - involved in the pathogenesis of allergic reactions and inflammation.

Question 39

Agranulocytes- what are they?

Answer 39

These are white blood cells which lack distinct granules in their cytoplasm.

Question 40

Two cells which are agranulocytes

Answer 40

lymphocytes and monocytes. monocytes develop into macrophages in the tissues which engulf bacteria and cell debris. They act as APCs to T cells in the adaptive immune system - These cells also release cytokines

Question 41

What are granulocytes?

Answer 41

cells with densely stained granules in cytoplasm. These granules contain enzymes which are released in the immune response. - can be called polymorphonuclear leukocytes due to the nucleus shape

Question 42

Three cells which are granulocytes

Answer 42

neutrophils, basophils and eosinophils.

Question 43

Lymphocytes are as we know agranulocytes. Give the three types

Answer 43

- B cells (and plasma cells)- antibody production - T helper cells- provide activation stimulus to other immune cells - Natural T killer cells- lyse/kill virally infected cells and cancer cells

Question 44

White blood cell/ Leucocyte disorders

Answer 44

Not enough leucocytes- due to HIV or chemo, for example: patient is immunosuppressed/immunocompromised and so is more susceptible to opportunistic infections. Too many- due to allergies, inflammatory conditions, autoimmunity, for example: immune system is activated inappropriately. Therefore, immunosuppressive drugs are given.