8.2 Blood: Structure & Composition

Question 1

what is blood?

Answer 1

a special connective tissue

Question 2

why is blood considered special tissue?

Answer 2

it is the only tissue that is mobile

Question 3

why is blood called a tissue?

Answer 3

it is a group of cells that all perform a similar function.

Question 4

why is blood called connective tissue?

Answer 4

its cells perform a function, but have a structural role as well.

Question 5

what percentage of blood is plasma?

Answer 5

55%

Question 6

what percentage of blood is cellular?

Answer 6

45%

Question 7

what percentage of blood is the ‘buffy coat’?

Answer 7

<1%

Question 8

what is the buffy coat?

Answer 8

WBCs and platelets

Question 9

what is the other name for platlets?

Answer 9

thrombocytes

Question 10

from what are platlets formed?

Answer 10

megakaryocyte

Question 11

how are platelets different than normal cells?

Answer 11

they are only cellular fragments, with no nucleus or major organelles.

Question 12

what is the average amount of platelets present in the blood?

Answer 12

450,000/dL

Question 13

what is the function of platelets?

Answer 13

clot a cut, plugging it and preventing blood loss.

Question 14

what are the two types of stem cells that produce the cells present in blood?

Answer 14

1. myeloid progenitor

2. lymphoid progenitor

Question 15

what are the types of cells that can form when a myeloid progenitor specialises?

Answer 15

1. RBCs
2. platelets
3. macrophages
4. basophils
5. neutrophils

Question 16

what are the types of cells that can form when a lymphoid progenitor specialises?

Answer 16

1. B cells

2. T cells

Question 17

where are haemopoetic stem cells present?

Answer 17

in the bone marrow.

Question 18

what is plasma composed of?

Answer 18

water (90%)
proteins (7%)
salts & lipids (3%)

Question 19

what are the three major proteins present in the blood?

Answer 19

1. albumin
2. clotting factors
3. immunoglobulins

Question 20

what is the role of albumin?

Answer 20

it 1) transports degradations of blood from the spleen to the liver; 2) maintains oncotic pressure

Question 21

what is oncotic pressure?

Answer 21

a form of osmotic pressure, induced by proteins in the blood plasma, that displaces H2O

Question 22

how does tissue fluid form?

Answer 22

when plasma leaks through the gaps between capillary cells into the spaces between body cells

Question 23

how is the composition of tissue fluid?

Answer 23

almost identical to that of blood plasma.

Question 24

why does plasma move out of the blood?

Answer 24

1. due to the presence of a solute conc. gradient;

2. because of high hydrostatic pressure on the arterial side of a capillary bed.