learning outcomes

Question 1

average circulating volume of blood in a grown man?

Answer 1

5 litres.
1 litres in lung, 1 in heart and arterial system.
3 in venous system

Question 2

functions of the blood?

Answer 2

1- thermoregualtion
2-controlling the volume of the ECF
3-immunity
4-carries oxygen in the blood
5-carries biological components in the blood
6-repairs connective tissue

Question 3

describe the composition of plasma

Answer 3

made up of different plasma proteins and (95%) water.

Question 4

name the plasma proteins and describe their function?

Answer 4

1- albumin: transports steroid hormones and lipids in the blood
2- globulin : gamma are antibodies, alpha/beta help transport fat-soluble vitamins
3-fibrogen and other clotting factors

Question 5

define the term colloid oncotic pressure and describe how it forms?

Answer 5

The pressure which allows fluid ( water and other nutrients which are dragged in) into the plasma from the ISF.
Forms as plasma proteins cannot cross capillary wall.
Concentration of fluid remains unchanged. Volume changes

Question 6

normal levels of circulating RBCs ,WBCs and platelets

Answer 6

RBC- 4,6 x10^12 per litre
WBC- 10^12 per litre
platelets- 140,400 x 10^9 per litre

Question 7

normal lifespan of an RBC and platelets

Answer 7

Rbc-120 days

platelet-10 days

Question 8

describe the function of a red blood cell?

Answer 8

contains a lot of haemoglobin so is able to transport oxygen around the body.

Question 9

describe erythropoietin: where is it synthesised and factors which may increase its secretion?

Answer 9

Erythropoietin stimulates the formation of erythroblasts from pluripotent stem cells.
It’s secretion increases as a result of hypoxia-low levels of 02 in the kidneys as a result of haemmorage, cardiac disease, anaemia.
erythropoietin is released by hepatocytes but mainly by peritubular capillary cells.

Question 10

name the five main type of WBC

Answer 10

granulocytes: neutrophil, basophil, eosinophil
Agranulocytes: lymphocytes and monocytes ( after 3 hours migrate to connective tissue where they become macrophages)

Question 11

what factors control WBC formation

Answer 11

Due to a combination of actions from different proteins.
Two most important are interleukins and colony stimulating factors.
They are released by mature WBC, fibroblasts and endothelial cells to produce cytokines.
Cytokines then divide further by mitosis and meiosis and differentiate.

Question 12

What is the unique function of platelets. What governs their formation?

Answer 12

It binds to damaged connective tissue and mediate clotting. Their formation is governed by thrombopoietin.

Question 13

What is meant by haematocrit?
what is the normal range for males and females?
how can circumstances change this?

Answer 13

It defines the proportion of RBCs in the blood .
In males between 40-54%
in females between 37-47%.
The ranges can be altered for example by living at high altitudes which would increase the need for more O2 so more haemoglobin.

Question 14

what is meant by blood viscosity?
normal value for plasma and RBCs.
what does it depend on?

Answer 14

It compares the thickness/stickiness of the blood compared to water.
Normal value for plasma is 1.8
normal value for RBCs is 3.4
Varies depending on temp, blood flow and haematocrit