Set 8 Flashcards
What are the three types of components of the immune system?
- Lymphoid tissues
- Various types of immune cells
- Chemical signals that coordinate responses
What are the primary functions of the immune system?
- Protects against pathogens
- Protects against foreign molecules
- Removes dead or damaged cells
- Attempts to recognize and remove abnormal cells
What are the three types of immune system pathologies? Give an example for each.
- Incorrect immune response (e.g. autoimmune disease)
- Overactive immune response (e.g. allergy)
- Lack of immune response (HIV-AIDS immunodeficiency)
What are the two lines of body defenses?
1) Physical and chemical barriers
2) Immune defenses
What are physical barriers?
- Skin
- Mucous membranes
- Lacrimal apparatus (ducts secreting tears)
- Saliva
- Epiglottis
What are four chemical barriers?
- Sebum
- Perspiration
- Gastric juice
- Urine
How does sebum inhibit microbial growth?
Sebum, secreted by sebaceous glands, has a low pH, which inhibits microbial growth
How does perspiration inhibit microbial growth?
Flushes skin of microbes and contains lysozyme
What are the four steps in an immune response?
1) Detection and identification of the foreign substance
2) Communication with other immune cells
3) Recruitment of other immune cells, and coordination of the response
4) Destruction or suppression of the invader
What is the lymphatic system?
Vascular system that collects tissue fluid and returns it to the blood
What is the function of the lymphatic fluid?
- Lymph travels through lymphatic vessels
- At lymph nodes, they are screened for pathogens
- Then, they travel back into the venous system
Why are lymph nodes particularly concentrated in extremities?
Screening mechanism for the blood in the extremities prior to their re-entry into the heart
What are the two primary lymphoid tissues?
- Bone marrow
- Thymus
What are the two encapsulated lymphoid tissues?
- Lymph nodes
- Spleen
What are diffuse lymphoid tissues? Give an example.
- Unencapsulated lymphoid tissues and aggregations of immune cells that appear in other organs of the body
- Respiratory and digestive tract
- Ex: gut-associated lymphoid tissue (GALT), and tonsils
What is the structure of the thymus? Where is it located?
- 2-lobed organ
- Located in the thorax just above the heart
What occurs to the thymus during adolescence?
- Reaches its greatest size during adolescence
- Then, shrinks and is replaced with adipose
What occurs in the thymus during development?
Recognition and elimination of self-reactive cells
What peptides does the thymus produce to aid in T-cell differentiation?
- Thymosin
- Thymopoietin
- Thymulin
How do lymphoid nodules differ from lymph nodes?
Lymphoid nodules are NOT surrounded by a fibrous capsule
Where are lymphoid nodules located? How do they differ in size?
- Beneath epithelial lining of organs that have direct contact to the outside world (digestive, respiratory (tonsils), urinary)
- Size increases or decreases depending on the number of dividing lymphocytes
What allows the creation of lymphatic fluid?
- Capillary hydrostatic pressure is greater than blood osmotic pressure, which favours filtration
- Blood colloid osmotic pressure exerts a force to bring fluid back in
How do viruses differ from bacteria?
- Viruses are NOT cells
- Viruses must have a host cell to reproduce
What is the function of glycoproteins on viruses?
Their particular glycoproteins allow them to attach to certain specific types of cells