Blood Week

Question 1

What are the four main components of blood?

Answer 1

Plasma, red blood cells (rbcs), white blood cells (wbcs) and platelets

Question 2

What is the function of blood?

Answer 2

Transport oxygen around the body, carry nutrients too, transport waste to kidney, regulate body temp and pH, form clots, and carry wbcs to fight infections.

Question 3

What are the average values of blood in a male and female?

Answer 3

12 pints in a man, 9 in a woman.

Question 4

What is serum and albumin?

Answer 4

Serum is plasma that lacks coagulation factors (clotting factors).
albumin is the most abundant protein in serum and plasma which transports hormones and fatty acids.

Question 5

Describe platelets

Answer 5

Platelets aren’t actually cells but fragments of megakaryocytes.
They become activated when collagen is exposed in the blood vessel when the endothelial layer is injured.
They form the plug

Question 6

What is the systemic circuit and the pulmonary circuit?

Answer 6

The systemic circuit is the flow of oxygenated blood from the heart to the body and the return of deoxygenated blood, whilst the pulmonary circuit is the flow of blood between the heart and lungs.

Question 7

Describe the basic structural differences between arteries and veins.

Answer 7

Arteries have a thicker endothelium wall and smaller lumen in diameter as they carry blood at a higher pressure.
Veins have valves to prevent the backflow of blood.

Question 8

What are the three layers of arteries and veins?

Answer 8

Tunica interna, tunica media, tunica externa.

Question 9

Describe the tunica intima.

Answer 9

Endothelium lining. wavy in arteries from constriction of smooth muscle, smooth in veins.
Internal elastic membrane in larger vessel (arteries only).

Question 10

Describe the tunica media.

Answer 10

It’s the thickest layer in the artery. made of smooth muscle and elastic fibers.
Nervi vasorum and vasa vasorum present in the vein and its made of smooth muscle and collagenous fibers.

Question 11

Describe tunica externa.

Answer 11

usually thinner than the media except for the largest arteries. collagenous and elastic fibers and the nervi vasorum and vasa vasorum found here.

in veins this is the thickest layer, and collagenous and smooth fibers.

Question 12

What is the nervi vasorum?

Answer 12

Control contraction and dilation of smooth muscle.

Question 13

What are the vasa vasorum?

Answer 13

They are involved in the exchange of nutrients and waste products from the cells of the vessels.

Question 14

What are the capillaries?

Answer 14

Capillaries are small beds of tiny arterioles and venules, one cell wall thick involved in the exchange of products.

Question 15

What are the three types of capillary?

Answer 15

Continuous- tight junctions between endothelial cells.

Fenestrated- pores for larger molecules to move in and out. e.g. kidney, small intestine

Sinusoid- most permeable due to swiss cheese appearance.
e.g. kidney, spleen, bone marrow.

Question 16

What are red blood cells?

Answer 16

Red blood cells deliver oxygen and are small and biconcave in shape.
they don’t contain a nucleus or mitochondria (ensures oxygen carried isn’t used in respiration).
They bind oxygen via haemoglobin molecules forming oxyhaemoglobin.
They are able to bind nitrous oxide too which is a vasodilator.

Question 17

How do people have different blood groups?

Answer 17

carbohydrate molecules on the glycolipid and glycoprotein coating.

Question 18

Describe the clotting process?

Answer 18

Vasoconstriction, collagen exposed activates platelets, which form a plug. prothrombin releases thrombin which activates fibrin from fibrinogen. this forms the soft lattice for the clot.
13th factor hardens the clot.

Question 19

Give examples of the importance of vitamins in the clotting process.

Answer 19

Factors 279 and 10 are vitamin K dependent.

Vitamin C is utilised by fibroblasts producing collagen.

Question 20

What are the intrinsic and extrinsic pathways?

Answer 20

The intrinsic pathway is initiated by platelets and is much slower, the extrinsic pathway is activated by damaged cells releasing tissue factor.
The intrinsic and extrinsic pathway converge to form the common pathway. where they converge is where coagulation factor X becomes Xa.

Question 21

What does sodium citrate do?

Answer 21

It stops blood clotting during transfusions or when in storage.

Question 22

What are stem cells?

Answer 22

Unspecialised cells that self renew indefinitely and can differentiate to become specialised cells.

Question 23

How do stem cells divide?

Answer 23

They divide asymmetrically. One cell will be an identical daughter cell, maintains the population. The other will have different genetic instructions

Question 24

What are haematopoietic stem cells and mesenchymal stem cells?

Answer 24

Haematopoietic stem cells give rise to blood and immune cells from bone marrow.
Mesenchymal stem cells make cells for skeletal tissues.