Blood - Circulatory System 1 Flashcards
Composition of blood
55% plasma
45% cells suspended within
What does blood transport?
- hormones (endocrines)
- heat
- antibodies
- clotting factors
- nutrients
- excretory products
- oxygen and carbon dioxide
Composition of plasma
90% water
10% dissolved substances
What are the dissolved substances?
- plasma proteins
- transported substances
What are the plasma proteins?
- albumin
- globulins
- fibrinogen
- prothrombin
- serum
Albumin
- Formed in liver
- Helps maintain viscosity of blood – ensuring
that the blood is not too thin and moving
through vessels too quickly - therefore
maintains blood pressure
Globulins
- Formed in liver or lymphoid tissue
- Produced during immune response
- Transports hormones and minerals
Fibrinogen
- produced in liver - necessary for haemostasis
Prothrombin
- essential substance in blood coagulation
- vitamin k is essential for its formation
Serum
- plasma from which clotting factors have been removed
What are the transported substances
- enzymes
- hormones
- nutrients
- organic waste products
- dissolved gases
- dissolved inorganic salts
Enzymes
- chemical substances which can produce or speed up changes in other substances
Hormones
Chemical substances from endocrine glands
Nutrients
- amino acids
- glucose
- fatty acids
- glycerol
- vitamins
Organic waste products
Principally urea and uric acid
Dissolved gases
- carbon dioxide
- oxygen
- nitrogen
Dissolved inorganic salts
- mainly sodium
- potassium
- calcium
- chloride
- bicarbonate
(Responsible for maintaining blood pH - 7.4)
What are the blood cells?
- erythrocytes
- leucocytes
- thrombocytes
Erythrocytes/red blood cells
- formed in red bone marrow
- corpuscles - have no nucleus
- biconcave discs - increases surface area for gas exchange, thinness in centre allows fast entry and exit of gases
- main function - gas transport (mainly oxygen)
- tend to clump together in groups (‘rouleaux formation’)
- 5 million per cubic millilitre of blood
Erythrocytes (2)
- short life span - 120 days
- development of erythrocytes known as erythropoesis
- vitamin B12 necessary for erythrocyte maturation
- ultimately destroyed in the spleen - haemolytic carried out by phagocytic cells
- contain haemoglobin
- An iron containing protein, concerned with oxygen transportation around the body
- Iron released from Haemolysis is retained and reused to form haemoglobin
Erythrocytes disorders?
ANAEMIA
- iron deficiency anaemia
- vitamin B12 deficiency anaemia
- sickle cell anaemia
Thrombocytes
- no true cell
- no nucleus
- fragments of larger bone marrow cells
- important in blood clotting
- 250,000 per cubic millilitre of blood
- life span - 8-10 days
- those not used in haemostasis - destroyed in spleen
- Control of Thrombocyte production
unclear but thought to increase if there is a decrease in circulating thrombocyte count
Thrombocyte disorders
THROMBOCYTOPENIA
- reduced platelet production
CONGENITAL DISORDERS:
- haemophilia
- Von Willebrand’s disease
