Name 4 anatomical and physiological barriers
- skin
- ciliary clearance
- low stomach pH
- lysozyme and saliva
What is the difference between non specific (innate) and adaptive (specific) immunity?
- We are born with non-specific immunity as it is innate and does not distinguish a potential threat from one another.
- adaptive immunity involves lymphocytes which are specific threats.
- defence against specific antigens is known as the immune response.
Where are lymphocytes found and where do they mature?
bone marrow and thymus gland
Where are monocytes and macrophages formed?
red bone marrow
Name 3 lymphatic organs that contain large numbers of lymphocytes
- thymus
- spleen
-lymoh nodes
What 3 things to lymphocytes respond to?
- foreign proteins
- invading pathogens- bacteria or viruses
- abnormal body cells- virus infected cells or cancer cells.
Name the 3 types of lymphocytes
- B cells
- T cells
- NK (natural killer cells)
Name the roles for each T cell:
1. Cyctoxic T cells
2. Helper T cells
3. Suppressor T cells
- directly attack foreign cells or virus-infected cells
- stimulate the activation of both T and B cells
- inhibit both T and B cells
Name 3 non-specific (innate) internal types of immunity
- phagocytic cells- ingest and destroy bacteria, cellular debris, denatured proteins and toxins.
- interferons- inhibit replication of viruses.
- compliment proteins- promote destruction of bacteria; enhance inflammatory response
Name an example of an external non-specific (innate) immunity for each structure:
1. Skin
2. Digestive Tract
3. Respiratory Tract
4. Genitourinary Tract
- Physical barrier to penetration, secrets lysosomes.
- High acidity of stomach- protection by normal bacteria population of colon.
- Secretion of mucus, movement of mucus by cilia; alveolar macrophages
- Acidity of urine, vaginal lactic acid.
How does innate immunity recognise bacteria?
- chemotaxis
- production of cytokines
- senses of cytokines produced
- antigens on bacteria
- bacteria cell wall is different to other cell walls
- ## neutrophils sense when bacteria enters the cell through the release of cytokines and they move to the area through chemotaxis.
Describe the process of phagocytosis b a neutrophil or macrophage
- Pseudopods- around bacteria, creating an extension of their cell wall
- extending their cell wall around the bacteria, creating pseudopods and surrounding bacteria to engulf.
- cellular ingestion of bacteria
-lysosomes release lysozymes to break down bacteria, in bacteria vessel formed by creating pseudopods
How does the temperature become raised in the hypothalamus?
Leukocytes attack bacteria, which produces endogenous pyrogen (cytokine), upsets and therefore raises temp.
What are interferons?
- A type of cytokines
- chemical messengers, that coordinate the defences against infections, interferons activated by lymphocytes and macrophages or virus-infected cells.
- normal cells exposed to interferon molecules respond by producing anti-viral proteins.
- they also stimulate NK cells and macrophages.
- non-specific, short-acting resistance to viral infection.
What are Mast cells?
small, mobile connective tissue cells, often found near blood vessels
Describe the process of inflammation
-when stimulated by mechanical stress or chemical changes in the local environment, mast cells release chemicals including heparin and histamines into the interstitial fluid.
- these chemicals begin the inflammation process.
- histamine makes capillaries more permeable and speeds up blood flow through the area.
- the combination of abnormal tissue conditions and chemicals released by mast cells stimulates local sensory neurons, producing pain sensations.
- increased blood flow reddness the area and raises local temperature, changes increase the rate of enzymatic reactions so will speed up phagocytosis
what is Cell-mediated immunity?
T cells provide a defence against abnormal cells and pathogens inside living cells.
What is antibody-mediated immunity/ humoral immunity?
B cells provide a defence against antigens and pathogens in body fluids.
What effects does inflammation have?
- injury is temporarily repaired, and additional pathogens are prevented from re-entering the wound.
- the spread of pathogens away from the injury is slowed.
How is oedema created in inflammation?
-increased blood flow to inflamed areas caused by vasodilation.
- increased permeability of capillary membrane fluid-fluid goes from capillary to space between cells (interstitial space).
- leaking of fluid into interstitial space- swelling and oedema.
What are eosinophils?
-weak phagocytes- White Blood Cells, that exhibit chemotaxis.
- they attack parasites
Name the 3 actions of eosinophils
- release hydrolytic enzymes from their granules, which are modified lysosomes.
-probably also by releasing highly reactive forms of oxygen that are especially lethal to parasites. - by releasing from the granules a highly larvicidal polypeptide called major basic protein.
what does an increased number of eosinophils in the blood suggest?
suggests a parasitic infection
What other cells are basophils similar to?
Why are they similar?
-mast cells
- They both circulate in the blood and located outside capillaries in the body.
- both release histamine and smaller amounts of bradykinin and serotonin.
- both coordinate inflammation by releasing these chemicals.
