Infection & Immune response

Define supine and prone position

Supine - the body is lay on its back with toes and face facing forward

Prone - the body is lay on its front

Define superior and inferior

Superior - towards the head

Inferior - towards the toes

Define anterior and prosterior

Anterior - towards the front facing of the body

Prosterior - towards the back of the body

Define ventral and dorsal

Ventral - towards the belly

Dorsal - towards the back

Define medial and lateral

Medial - if something is medial it means it is closer to the midline 9midline of the body running vertically)

Lateral - further away from the midline

Define proximal and distal

Proximal - limbs which are closer to the trunk

Distal - limbs which are further away from the trunk

Define superficial and deep & Define external and internal

Superficial - closer to the surface

Deep - further from the surface

External - outer surface

Internal - inner surface

Define extension and flexion

Extension - increase the angle

Flexion - decrease the angle

Explain the role of the lymphatic system

The lymphatic system is made up of lymphatic vessels, lymph and lymph organs. It is responsible for the removal of interstitial fluid from tissues and it is then known as lymph. It absorbs and transports fat from the digestive system and is involved in the immune system and production of mature lymphocytes and detecting foreign antigens.

What is lymph & how is it formed

Higher blood pressure in capillaries cause water to leak from them into the interstitial space (the space between the cells). Osmosis draws some of the fluid back into the capillary however there is some excess fluid and found in the interstitial space, this must be re absorbed and put back into the blood circulation and this is done using lymphatic vessels. These vessels can absorb interstitial fluid and small proteins which have been leaked, the vessels are lined with endothelial cells which allows fluid to enter lymphatic capillary, this fluid is now known as lymph.

What are lacteals & their role

Lacteals are lymphatic vessels within the villi of the small intestine, they absorb large dietary fats that can’t enter the bloodstream. The fats are transported in the lymphatic system to the circulatory system first adsorption.

How does lymph flow

From the lymphatic capillaries, larger lymphatic vessels carry and return lymph back to the circulatory system.

Give examples of how lymph is transported

Pulsation from close by arteries and compression helping to move lymph along the vessels and from surrounding muscles can help move lymph towards trunk by doing things like walking.

What prevents the backflow of lymph

Valves in the lymphatic system

What is the structure of lymphatic trunks

Lymphatic trunks are made when lymphatic vessels come together.

Outline the process of lymphatic drainage

Lymphatic trunks (in the right side); side of the neck, head, upper limb, thorax, upper abdominal wall which all drains fluids into the right subclavian vein in the root of the neck via the right lymphatic duct. Lymph from all other regions drains into the thoracic ducts then to the left subclavian vein

Summarise lymph drainage in the body

Lymphatic vessels > lymphatic trunks > lymphatic ducts > blood circulatory system > subclavatory veins.

What are the primary and secondary lymphoid organs

Primary; bone marrow and thymus which are responsible for production of mature lymphocytes.

Secondary; lymph nodes, tonsils, spleen, MALT/GALT/BALT which are responsible for filtering where antigens are detected and antigen-driven proliferation and differentiation occurs.

What is the structure of lymph nodes

Small structures which interrupt the lymphatic vessels, they are dense areas of lymphoid tissue which allows fluid are surrounded by a dense fibrous capsule.

What are afferent lymphatic vessels

enter the lymph node

What are efferent lymphatic vessels

exit the lymph node

What is the role of lymph nodes

Filter lymph to detect any foreign antigens and mount an immune response

How do lymph nodes react to infection

they can become swollen or painful, this suggests that the immune systems are active and there is underlying infection eg cold, dental decay, ear infection or when there’s cancer present because cells can break away from the primary tissue and move to the lymph node to create a secondary tumour.

What is the definition of microbiology

The study of microorganisms and their relationship with humans

What is the structure of antibodies

They are Y shaped macromolecules consisting of 4 polypeptide chains (quaternary structure) called immunoglobulins, these 4 chains are 2 heavy and 2 light chains which are joined together by a disulphide bond. They have a variable region, this is the region which is different for different antibodies as this is where the antigen binds. There is also a constant region on the antibodies found at the bottom of the light chain.

What is the Fab and Fc domains

Fab domain; binds to antigen

Fc domain; binds to complement (the heavy chains)

What is IgM antigen

This is a pentamer and is the first antigen produced, strong binding to antigen

What is IgG antigen

It is a monomer, most abundant antibody and crosses the placenta for immunoprotection for developing foetus

What is IgA antigen

It is a dimer, secreted so found in tears, saliva, mucus membranes of resp & GI systems and in breast milk too

What is IgE antigen

It is a monomer, produces allergic response and parasitic immune response

What is IgD antigen

It is a monomer found on the surface of B cells

What are the 3 processes that occur during adaptive immune response

Neutralisation, Opsonisation, Complete activation

What is the process of neutralisation

antibody will coat toxin/virus and will neutralise the activity that it wants to do

What is the process of opsonisation

pathogen is coated in antibody making it more recognisable for macrophages to phagocytose it.

What is complete activation

triggers response to eliminate pathogens, clear damaged cells.

List the primary lymphoid organs

bone marrow and the thymus

What is the function of the primary lymphoid organs

These organs are responsible for the production and maturation of lymphocytes.

State the secondary lymphoid organs

Lymph nodes, spleen, throat, intestine

What is the function of secondary lymphoid organs

Structures where the T&B lymphocytes go to understand what is going on in the body and can then fight/respond accordingly eg producing antibodies.

Explain how T Lymphocytes develop

The process is initiated with haematopoiesis where a haematopoietic stem cell differentiates into a lymphoid progenitor cell and furthermore into a lymphocyte then T lymphocyte. They then leave the blood and go to the thymus, the thymus is where the T lymphocytes develop into fully functioning cells, they are then released back into the bloodstream.

Summarise the role of T helper lymphocytes

T helper cells act as a conductor of the adaptive immune system by activating B lymphocytes by signalling to them to produce antibodies to help fight antigens.

List the symptoms of inflammation & why they occur

Redness; vasodilation

Heat; vasodilation and fever

Swelling; fluid in the extracellular matrix

Pain; pain mediators such as serotonin and bradykinin

Loss of function; caused by swelling and pain

Describe inflammation as a protective response

Localises the immune systems attention to the area if infection bringing cells/molecules to the areas to repair damage that may have been caused due to the infection.

What are the benefits of inflammation

Isolates the damaged area so prevents metastasis of infection

Mobilises effector cells and molecules to the site so that immune cells and molecules can be distributed throughout the body. Promotes healing and tissue repair so creates environment conductive to repair. Overall it protects the body

Outline the problems with too much inflammation

If inflammatory responses become out of proportion or outlive the threat they are dealing with, they can cause more damage to the body than the infection/trauma itself would have produced. Thus resulting in organ/tissue damage so a loss of function or allergies, autoimmune disease, chronic inflammatory conditions, cardiovascular disease.