Blood Flashcards
What are the functions of Blood?
1) Transport
2) Electrochemical Regulation
3) Restriction of fluid loss due to damage
4) Defence
5) Temperature Homeostasis
What does the Blood transport?
Gases
Nutrients
Hormones
Waste Products
What does the Blood help regulate?
pH
Electrolyte composition of interstitial fluid
What percent of body weight does blood make up?
8%
In blood, how much is plasma and how much is formed elements [RBCs, WBCs]?
55% Plasma
45% Formed Elements
What does plasma consists of?
7% Proteins [Albumins, Globulins, Fibrinogen]
91% Water
2% Other Solutes [ions, nutrients, waste products, gases, regulatory substances]
How many formed elements are there per cubic mm?
250-400,000 Thrombocytes
5-9,000 Leukocytes [WBCs]
4.2-5.8m Erythrocytes [RBCs]
What do the Leukocytes consist of?
60-70% Neutrophils 20-25% Lymphocytes 3-8% Monocytes 2-4% Eosinophils 0.5-1% Basophils
What is the function of Albumins?
Maintain osmotic pressure of the Plasma [make up 60% of plasma proteins]
What is the function of the Globulins?
Include Antibodies [Ig, Immunoglobulins]
Antibodies aid in Immunity
Transport proteins bind to substances to prevent their loss at the kidneys
What is the function of Fibrinogen?
Blood Clotting
What are the Erythrocytes?
RBCs
Contain Hb to bind and transport O2/CO2
Large SA:V ideal for maximising diffusion rates
Flexible so can pass through narrow capillaries
No nucleus - loose most of other organelles as well
What is Haemoglobin [Hb]?
Tranports O2/CO2 [>95% of RBC Protein]
Quaternary structure that contains 4 subunits [each with molecule of Haem]
What is a difference between Adult and Foetal Haemoglobin?
Foetal Haemoglobin binds O2 more readily than Hb of Adults
Foetus can “steal” O2 from maternal bloodstream
What is Erythropoiesis?
RBC/Erythrocyte Formation:
Where does Erythropoiesis occur?
In Red Bone Marrow
What happens in Erythropoiesis?
1) Haemocytoblasts in red marrow produce myeloid stem cells which produce RBCs
2) Erythroblasts [immature RBCs] produce Hb [stage lasts 4D]
3) Nucleus is shed and cell becomes Reticulocyte [enter circ after 2+D in marrow]
4) After 24hrs in circulation, Reticulocyte becomes mature Erythrocyte
What is Erythropoietin [EPO]?
Hormone that stimulates Erythropoiesis
When is EPO released?
Release is stimulated by low O2 levels [Hypoxia]
1) Released during anaemia [b/c blood flow to kidneys declines] and low O2 in air or the lungs [due to environment/disease]
What does EPO stimulate?
Stimulates division of Erythroblasts and Myeloid Stem Cells
Speeds up RBC maturation by increasing Hb synthesis
Why is EPO controversial?
Athletes use synthetic EPO to increase amount of O2 available for exercise
What are other examples of Blood Doping in Sport?
Synthetic Haemoglobin can be injected in increase O2 capabilities
What are the different blood types?
A+/A-
B+/B-
AB+/AB- [Universal Receiver]
O+/O- [Universal Donor]
When does blood clotting occur?
Occurs when blood vessel has been damaged
