BIOL1003 Lecture Notes - Lecture 7: Pernicious Anemia, Aplastic Anemia, Folate Deficiency
Describe the composition and functions of blood
Functions
Transport of gases, nutrients
and waste products
Oxygen enters blood in lungs and carried to cells
•
CO2 produced by cells, carried in blood to lungs then expelled
•
Ingested nutrients, ions and water form digestive tract to cells
•
Waste products of cells to kidneys for elimination
•
Transport of processed
molecules
Many substances produced in one part of body then transported
in blood to another part for modification
•
Transport of regulatory
products
Blood carried hormones and enzymes that regulate body
processes from one part of the body to another
•
Regulation of pH and osmosis
Buffers help keep blood pH within normal limits in blood
•
Osmotic composition of blood critical for maintaining normal
fluid and ion balance
•
Maintenance of body
temperature
Warm blood transported from interior of body to surface, where
heat is released from the blood
•
Helps regulate body temp
•
Protection against foreign
substances
Certain cells and chems in blood part of immune system
•
Protect against antigens
•
Clot formation
When blood vessels are damaged, clotting protects against
excessive blood loss
•
When tissues damaged, blood clot is first step in tissue repair
and restoration of normal function
•
Composition
Plasma = liquid matrix
-
Formed elements = cell fragments
-
Main constituents
Plasma
Composed of water, salts, nutrients, wastes, dissolved gases, plasma
proteins
•
Albumin - maintains osmotic pressure
•
Globulins - immune system
•
Fibrinogen - clotting factor
•
Dissolved proteins
•
Erythrocytes/RBCs
Disk shaped
•
Looks like werthers, biconcave shape increases cells surface area compared
to flat disk shape
•
Larger surface area = easier movement of gases
•
Can bend or fold to decrease size to pass through smaller blood vessels
•
Unable to divide, no nuclei
•
Binds to oxygen, picks up oxygen in lungs and releases it in other
tissues
•
Contains iron to replace small amounts lost in urine and faeces
•
Contains haemoglobin pigment = red colour
•
Transports oxygen and CO2
•
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11:48 AM
7. Circulatory system Page 1
Transports oxygen and CO2
•
Leukocytes/WBCs
Spherical
•
Lack haemoglobin
•
Larger than RBCs
•
Contain nuclei
•
Can leave blood and travel through tissues
•
Protects body against pathogens
•
Removes dead cells and debris form tissues by phagocytosis
•
5 types, each with specific functions
•
Neutrophils
•
Basophils
•
Eosinophils
•
Granulocytes
•
Lymphocytes
•
Monocytes
•
Agranulocytes
•
Platelets/thrombocy
tes
Cytoplasm surrounded by plasma membrane
•
Contains granules
•
Smaller than WBC and RBCs
•
Produced in red bone marrow
•
Forms platelet plugs
•
Releases chemicals necessary for blood clotting, prevents blood loss
•
Screen clipping taken: 3/06/2017 12:05 PM
Haematocrit - describes percentage of blood made up of RBCs
7. Circulatory system Page 2
Explain the mechanism of clotting
When blood vessel severely damaged, blood clotting or coagulation results in clotting
-
Clot = network of threadlike protein fibres, fibrin, that traps blood cells, platelets and fluid
-
Activated following injury
○
Clotting factors = proteins in plasma that help form blood clot
-
Inactive clotting factors come into contact with exposed connective tissue -> activation
a.
Chemicals e.g. thromboplastin released from injured tissues -> activation of clotting
factors. After initial clotting factors activated, then activate other clotting factors.
Results in series of reactions until clotting factor prothrombinase is formed
b.
Chemical reactions can be started in 2 ways
1.
Prothrombinase converts inactive clotting factor Prothrombin to active form thrombin
2.
Thrombin converts plasma protein fibrinogen to fibrin
3.
3 stages of clot formation
At each step, clotting factor activates many additional clotting factors -> clot formation
-
Most clotting factors manufactured in liver, and many require Vit K for synthesis
-
Chem reactions require Ca2+ and chems released from platelets
-
Anticoagulants prevent clotting factors from forming clots under normal conditions
-
Antithrombin and heparin - inactivate fibrin and no clot forms
-
When clotting factors activated, anticoagulants can no longer prevent clot formation
-
Control of clot formation
7n)
Saturday, 3 June 2017
5:17 PM
7. Circulatory system Page 3
Document Summary
Oxygen enters blood in lungs and carried to cells. Co2 produced by cells, carried in blood to lungs then expelled. Ingested nutrients, ions and water form digestive tract to cells. Waste products of cells to kidneys for elimination. Many substances produced in one part of body then transported in blood to another part for modification. Blood carried hormones and enzymes that regulate body processes from one part of the body to another. Buffers help keep blood ph within normal limits in blood. Osmotic composition of blood critical for maintaining normal fluid and ion balance. Warm blood transported from interior of body to surface, where heat is released from the blood. Certain cells and chems in blood part of immune system. When blood vessels are damaged, clotting protects against excessive blood loss. When tissues damaged, blood clot is first step in tissue repair and restoration of normal function. Composed of water, salts, nutrients, wastes, dissolved gases, plasma proteins.