15 terms

The circulatory system: blood

What are the functions of the circulatory system

•white blood cells

•fluid volume
Name and describe the components of blood
adults-4/6 litres


-90% water
-8% proteins / albumins/globulins/fibrinogens
-2% other / amino acids/wastes/nutrients/O2/CO2/electrolytes

Explain the importance of blood viscosity and blood osmolarity
Increased RBC count = increased viscosity = increased blood volume/pressure

High osmolarity = high fluid absorption

low osmolarity = fluid remains in tissues
Describe the structure and function of erythrocytes and their relationship to haemoglobin
lack nucleus, organelles (mitochondria), contains cytoskeletons.
Basically bags of haemoglobin 280 million
7.5 micrometers
Describe the life cycle of erythrocytes
120 day life span

Erythrocytes produced in the red bone marrow, erythropoiesis (takes 3.5 days)

Pluripotent stem cell
colony forming unit
erythroblast - nucleus becomes reticulocyte

RBC lyse in spleen
macrophages destroy destroy RBC
Haem + Globin are split
iron is salvaged and hydrolysed into amino acids

Haem turns to biliverdan and iron
•biliverdan becomes biliruben
What is anaemia, it causes and consequences of this condition
Anaemia - blood is abnormally carrying low oxygen
•decreased RBC count
•low haemoglobin content (vitamin b12 deficiency)
•hereditary defects (sickle cell anaemia)
Hypoxia results with no oxygen, oedemas form due to reduced osmolarity, cardiac failure as viscosity drops.
What determines a persons ABO and RH blood type and how does this relate to transfusion compatibility
Blood type are determined by the presence of glycoproteins called antigens on the RBC

these help to determine which matter is its own

RBC's can have:
•A antigens
•B antigens
•AB antigens
•O antigens

the RH is the presence of the D antigen, positive if present.

The presence of antibodies and antigens is related to the transfusion compatibility
What is haemolytic disease of the newborn and why does it occur?
Occurs with the second newborn (RH+)
mothers (RH-) anti D antibodies cross placenta

prevented with Rohlum
Detail relative abundance of each of the five leucocytes
Describe the structural characteristics of each of the five leukocytes and their functions
•fine granules in cytoplasm
•3-5 lobed nucleus
•phagocytosis of bacteria
•release antimicrobial chemicals

•variable amounts of blueish cytoplasm
•destroy cells
•present antigens to activate other immune cells
•secrete antibodies and provide immune memory

•largest type
•kidney shape nucleus
•differentiate into macrophages
•phagocytosize pathogens and debris
•present antigens to active other immune cells

•nucleus has two large lobes
•phagocytosize of antigen antibody complexes, allergens and inflammatory chemicals
•release enzymes to destroy parasites

•large, abundant, violet granules
•s shaped nucleus
•secrete histamine
•secrete heparin
Describe the life cycle of leukocytes
pluripotent cell
•myoblasts - form nuetrophils, eosinophils, basophils
•monoblasts - form monocytes
•lymphocytes - form form BT lymphocytes and natural killer cells

red bone marrow stores and release granulocyte and monocytes

circulatory WBC do not stay in bloodstream
-granulocytes leave 8 hours, live 5 days longer
-monocytes leave 20 hours, live several years
-WBC long term - decades
What are platelets and what are their functions
•Call fragments of megakaryotes
•essential to clotting
•involved in all 3 mechanisms of hemostasis
•live for 10 days
•secrete vasoconstrictors
•seal small seal breaks
•secrete clotting factors/growth factors
•initiate clot dissolving enzyme
•phagocytocize bacteria
•secrete neutrophil and monocyte attractors to inflammation site
Explain the first three mechanisms of hemostasis
•Vasoconstriction (vascular spasm)
injury to smooth muscle

•Platelet plug formation
platelets adhere to exposed collagen fibres of endotehlium
psuedopods stick
platelets degranulate secreting dialators
positive feedback until vessel sealed

clotting plasma protein fibrinogen converts to insoluble threads, procoagulation, activation of cascade
extrinsic initiated by damaged walls
intrinsic initiated within blood
What keeps blood clotting in the absence of injury?
Platelets do not stick to prostacyclin coating

thrombin dilution

Natural anticoagulants: heparin/anti thrombin
What are some consequences of unwanted blood clotting