Lecture 1 introduction Flashcards
What are some threats from outside the human body?
microorganisms and toxic agents
What are some threats from inside the human body?
malignant transformation of normal cells to cancer cells
What is the defense mechanism of the body?
The immune system,
can identify and neutralize all threats
distinguish non self organisms and cells from self.
What is the first line of defense?
innate immune system
What is the second line of defense?
adaptive immune system
When is the 2nd line of defense activated?
If the first line is breached, then the second line is activated
What are the physical components of the immune system?
- Tissues and organs (lymphoid tissues or organs)
2. Cells (lymphoid cells)
What are the two categories of lymphoid tissues and organs?
- PRIMARY / central
2. Secondary (peripheral)
What are the PLTs classified into?
- Bone marrow
- Thymus
Functions of the PLT?
Origination and development or maturation of the immune cells.
What does the BM contain?
- Contains connective tissue, blood vessels, fat and cells.
- Hematopoietic stem cells(pluripotent).
- Site for production and development of immune cells
Development of the thymus
- First lymphoid organ to develop.
- Bilobed capsulated organ.
Location of the thymus
Located in superior mediastinum anterior to heart and great vessels.
Size of the thymus
- Increases in size during fetal and neonatal life.
- Progressively involutes following puberty.
Population of the thymus
lymphocytes
organization of the thymus
Organized into an outer region(cortex) and inner region(medulla).
cells of the thymus
lymphocytes, dendritic cells, macrophages and epithelial cells.
function of the thymus
forms the site for development of T-lymphocytes.
What are the secondary lymphoid tissues?
- Spleen
- Lymph nodes or glands(superficial and deep)
- Mucosa associated lymphoid tissues in
- Gut (GALT)
- Respiratory(bronchus) system(BALT)
- Peyers patches
- Urogenital system
- Tonsils
location of the spleen
Capsulated, found in left hypochondrium behind the stomach.
divisions of the spleen
Divided into white pulp rich in lymphocytes and red pulp rich in erythrocytes.
filtration action of the spleen
Filtration device ,removing foreign matter, dead cells and protein aggregates from the circulation.
concentration of the spleen
Concentrates blood-borne antigens and microbes.
contents of the spleen
Contain B- lymphocytes,T-lymphocytes,plasma cells.
function of the spleen
Form the site for interaction of immune cells to produce an immune response.
shape of the lymph nodes
Small round or oval capsulated lymphoid organ.
locations of the lymph nodes
Present around large arteries and veins; Cervical L.N,axillary L.N,Coeliac and Mesenteric L.N and Inguinal L.N.
number of lymph nodes in the body
400-450 L.N in normal young adult.
divisions of the lymph nodes
Divided into the deeper cortex and inner medulla homing the T-lymphocytes.
functions of the lymph nodes
Function as filter to purify lymph prior to return to the blood circulating system.
What is MALT?
- largest mammalian lymphoid organ
- Mucosal associated lymphoid tissue
- specialized immune barrier
What cell type is MALT comprised of?
40-60% of all lymphocytes
What are the subdivisions of MALT?
- GALT (GI, PP, appendix)
- BALT (bronchus)
- NALT (nasopharyngeal)
- Salivary and lacrimal glanda
- Genitourinary tract
