The immune system Flashcards
What 3 things does blood help to regulate?
-pH
-body temperature
-water content of cells
How does the blood prevent against blood loss?
Through clotting and combats microbes and toxins through the action of certain phagocytic white blood cells or specialised plasma proteins
What actually is blood and what is its 3 general functions?
-a liquid connective tissue that consists of cells surrounded by extracellular matrix
-transportation, regulation, protection
Explain how the blood fulfils one of its functions, transportation
-blood transports oxygen from the lungs to cells throughout the body and carbon dioxide from the cells to the lungs
-it also carries nutrients from the gastrointestinal tract to body cells, heat and waste products away from cells, and hormones from the endocrine glands to other body cells
Explain how the blood fulfils one of its functions, regulation
-blood helps regulate the pH of bodily fluids
-heat absorbing coolant properties of the water in blood transport and its variable rate of flow through the skin help adjust body temperature
-blood osmotic pressure also influences the water content of cells
Explain how the blood fulfils one of its functions, protection
-blood clots become gel-like in response to an injury, which protects against its excessive loss from the cardiovascular system
-white blood cells protect against disease by carrying on phagocytosis and producing proteins called antibodies
-blood contains additional proteins called interferons and complement that also help protect against disease
What are the physical components of whole blood?
-a viscosity greater than that of water
-temperature of 38 degrees
-a pH range between 7.35 and 7.45
-blood constitutes about 8% of body weight in an adult, and consists of 55% plasma and 45% formed elements
What are the formed elements in blood?
-red blood cells (erythrocytes)
-white blood cells (leukocytes)
-platelets
What percentage of water, proteins and solutes (other than proteins) are contained in blood plasma?
-91.5% water
-7% proteins
-1.5% solutes
What are some of the principal solutes contained in blood plasma?
-proteins (albumins, globulins, fibrinogen)
-nutrients
-hormones
-respiratory gases
-electrolytes
-waste products
What is hemopoiesis and where does it occur?
-formation of blood cells from pluripotent stem cells
-occurs in red bone marrow
What are the granular leukocytes contained in the formed element portion of the blood?
- neutrophils
- eosinphils
- basophils
What are the agranular leukocytes contained in the formed element portion of the blood?
- T and B lymphocytes and natural killer cells
- monocytes
What is innate (nonspecific) immunity and the first and second line of defence?
-includes the external physical and chemical barriers provided by the skin and mucous membranes (first line of defence against pathogens)
-also includes various internal defences such as antimicrobial substances, natural killer cells, phagocytes, inflammation and fever (second line of defence incase any pathogens get past the first line)
What are the 4 main types of antimicrobial substances that discourage microbial growth which are found in various body fluids?
- interferons
- complement system
- iron-binding proteins
- antimicrobial proteins (AMPs)
What is the third line of defence (nonspecific)?
consists of phagocytes and natural killer cells
What is inflammation?
a nonspecific defensive response of the body to tissue damage
What is a fever?
an elevated body temperature that intensifies the effect of interferons, inhibits the growth of some microbes, and speeds up body reactions that aid repair
What is adaptive (specific) immunity?
the production of specific types of cells or specific antibodies to destroy a particular antigen
What is an antigen?
any substance (foods, microbes, drugs, pollen etc) that the immune system recognises as foreign
Where do the B and T cells involved in adaptive immunity develop?
in primary lymphatic organs, the red bone marrow and the thymus, from stem cells that originate in red bone marrow
What are the two types of adaptive immunity?
- cell-mediated immunity (cytotoxic T cells directly attack invading antigens)
- antibody-mediated immunity (B cells transform into plasma cells, then into antibodies)
What is clonal selection?
-a process by which a lymphocyte proliferates and differentiates in response to a specific antigen
-the result of clonal selection is the formation of a clone of cells that recognise the same specific antigen as the original lymphocyte
-a lymphocyte that undergoes clinical selection gives rise to two major types of cells in the clone- effector cells and memory cells
What is the role of effector cells?
-they carry out immune responses that ultimately result in the destruction or inactivation of the antigen
-effector cells include helper T cells, active cytotoxic T cells, and plasma cells
What is the role of memory cells?
-do not actively participate in the initial immune response
-if the antigen reappears in the body in the future, the memory cells can quickly respond to the antigen by proliferating and differentiating into more effector cells and more memory cells
-memory cells include memory helper T cells, memory cytotoxic T cells, and memory B cells
Describe the structure of an antibody
