Compendium 10. Immunity Flashcards
What are the 3 main functions of the lymphatic system?
- Fluid balance
- Fat absorption
- Defence against infection
What is a lymph?
Clear fluid made up of water and solutes. It drains through the lymphatic system and back into the blood via veins.
What are lymphatic vessels?
They are one way, beaded vessels that carry lymph away from tissues and back to the heart.
The movement of the lymph is aided by the contractions of skeletal muscles.
What are 4 features of the lymphatic capillaries / blind ended capillaries?
- They are more permeable than blood capillaries.
- It has one way flow
- Epithelial cells do not have basement membranes
- Found in all parts of the body except for nervous system, bone and avascular
What are lymphatic trunks?
Large lymph vessels where smaller lymph vessels join
They drain lymphs and are named according to where they are situated in the body.
Where is the Jugular lymphatic trunk?
Head and neck
Where are the Subclavian lymphatic trunks?
Upper limbs, thoracic wall and mammary glands
Where are the Bronchomediastinal lymphatic trunks?
Thoracic organs and deep thoracic wall
Where are the Intestinal lymphatic trunks?
The abdominal organs
Where are the lumbar lymphatic trunks?
Lower limbs and organs in the pelvis
What are lymphatic ducts?
They drain tissues into major veins. There are 2 ducts :
- The right lymphatic duct
- The thoracic duct
What parts of the body do the two lymphatic ducts drain?
- Right lymphatic duct drains the right side of the body, right-upper limb and right thorax.
- Thoracic duct drains the rest of the body
What are some examples of encapsulated tissue?
- Lymph nodes
- Spleen
- Thymus
What are some examples of non-encapsulated tissue?
Mucosa-associated tissue
What are diffuse lymphatic tissue?
- Has dispersed lymphocytes and macrophages
- It does NOT have clear boundaries
What are lymphatic nodules?
- Is denser that diffuse lymphatic tissue
- numerous in loose connective tissue in the digestive, respiratory and urinary system
What are lymph nodes?
- Filter lymphs
- They activate the immune system
- The site in which lymphocytes will proliferate
What are tonsils?
- Large groups of lymphoid tissue in the nasopharynx and oral cavity
- They provide protection against pathogens that enter the mouth and nose cavity
What are the 3 different sets of tonsils?
- Palantine - The ones you can see at the back of the throat
- Pharyngeal - They sit in the posterior walls of the nasopharynx
- Lingual - Located at the base of the tongue
What is the spleen and what are it’s main functions?
The largest lymphatic organ in the body.
- It monitors blood by detecting and responding to foreign antigens
- Destroys defective red blood cells
- Contains a reserve of red blood cells.
Describe the difference between the red and white pulp of the spleen
Red pulp - associated with the veins and makes up 75% of spleen. It contained many red blood cells and macrophages.
White pulp - associated with arteries and makes up around 25% of spleen. It is full of lymphatic tissue.
What is the thymus?
It is the site of the maturation of T cells.
What are trabeculae?
A series of parturitions formed by bands or columns of connective tissue
Describe the process of the lymphatic system
- Lymphatic capillaries remove fluid from tissues. This fluid becomes the lymph.
- Lymph flows through lymphatic vessels.
- Lymph nodes filter lymph and respond to infections where necessary.
- Lymph enters thoracic duct or the right lymphatic duct.
- The lymph enters the blood stream
What is the difference between the lymphatic system and the immune system?
The lymphatic system :
- Is the transport for cells of the immune system and antigens to travel around the body.
- Lymphatic tissues are where lymphocytes ‘hang out.’
The immune system :
- Is the collection of proteins, cells, tissues and organs that fight pathogens.
Define pathogens
Foreign agents that bring non-self antigens into the body. Examples of pathogens include : - Worms - Toxins - Fungi - Viruses
What are the 2 types of immunity?
- Innate (non specific)
2. Adaptive (specific)
What is involved in innate immunity? (hint, there are 4 processes/cells)
- Physical barriers : skin and mucous membranes
- Inflammation
- Chemical mediators
- White blood cells
What are chemical mediators?
Chemicals that promote phagocytosis and inflammation.
An example may be cytokines which regulate the intensity and length of the immune response to a pathogen.
What chemicals do mast cells release and what are their purpose?
- Histamine ; increases blood flow to the area and makes the capillaries more permeable
- Heparin ; prevents blood clotting at the area of injury
- Chemicals that attract phagocytes, macrophages and leucocytes.
What is the difference between macrophages and phagocytes?
Macrophages are a type of phagocyte
What are the 4 features of inflammation and what are they caused by?
- Redness - increased blood flow.
- Heat - increased metabolic activity and blood flow.
- Swelling - increased fluid concentration.
- Pain - fluid stimulates pain receptors
What are 3 purposes of fever?
- Denature pathogenic organisms
- Increases the metabolic activity of some disease fighting organisms
- Helps repair tissue
What are the 2 types of adaptive immunity?
- Cell-mediated immunity (T-Cells) : These attack the target cells that have been infected by antigens.
- Antibody-mediated immunity (B-Cells) : These use antibodies to unprocessed antigens.
List 3 ways antibodies can work
- Dissolve organisms
- Agglutination
- Bind to the surface of viruses to prevent them from entering cells.
Where are the mediastinal lymph nodes located?
Between the sternum and the spinal column
Where are the axillary lymph nodes located?
Under the armpits
Where are the inguinal lymph nodes located?
In the groin area
Where are the iliac lymph nodes located?
In the pelvic area
Define proliferate
To increase in number
At what year of age does the thymus stop growing?
1 year
