The Lymphatic system Flashcards
What does the lymphatic system consist of?
Lymph
Lymphatic vessels
Lymphatic tissue
Red bone marrow
What are the functions of the lymphatic system?
- Drainage of interstitial fluid
- Transporting dietary lipids and lipids soluble vitamins
- Facilitation of immune response
What is hydrostatic pressure?
The pushing force exerted by a fluid
What is interstitial fluid pressure?
Proposed to be slightly negative which contributes to the outward pull of fluid from capillaries.
What is colloidal osmotic pressure?
The pulling force created by blood proteins that are too large to pass through the pores of the membrane
What is interstitial osmotic pressure?
Created by a small number of plasma proteins that have leaked into the extracellular tissue space
How is interstitial fluid formed?
Blood hydrostatic pressure pushes blood plasma out of the blood capillaries to bathe the surrounding tissues.
The blood plasma is now known as interstitial fluid
How is osmotic pressure built up?
The blood protein, Albumin, is too large to leave the capillaries and creates an osmotic pressure. This pulls interstitial fluid back into the blood capillaries
How is interstitial pressure drained?
It needs to be drained or swelling will occur (oedema)
Drainage occurs via the lymphatic capillaries and lymph vessels.
How is lymph drained?
Lymph capillaries join to form lymph vessels. These vessels have certain internal structures to ensure the one way flow of lymph.
It is then drained into one of two ducts which return the lymph to the blood.
How does the cardiovascular system and the lymphatic system work together?
- Plasma form interstitial fluid
- Interstitial fluid is returned to the plasma
- Fluid that’s not returned to plasma enters the lymph capillary to form lymph
- lymph is returned to the cardiovascular system
What factors influence oedema?
- Increased capillary filtration pressure
- Decreased capillary colloid osmotic pressure
- Increased capillary permeability
- Obstruction to lymph flow
Where are lymph nodes located?
Tonsils Thymus Spleen Peyer's patches Appendix
What is a lymph node?
Found along lymph vessels, they are bean-shaped structures that receive the lymph from afferent vessels.
The lymph is the drained by efferent vessels
What do lymphocytes do?
Produce antibodies.
Found between the reticular cells
What does MALT stand for?
M - mucosa
A - associated
L - lymphoid
T - tissue
What is MALT?
a collection of nodules which are found in the mucosa of tubular structures in respiratory, reproductive and urinary
How many tonsils do we have and what are they called?
2 x palatine tonsils
2 x lingual tonsils
1 x pharyngeal or adenoid
What do tonsils do?
Filters air
What is the thymus gland?
A gland that produces thymic factors.
Thymic factors is important in setting up the immune system and the formation of T cells
When is the immune system at its most active?
When it is being established during childhood.
As a result, the thymus is at its largest during childhood
Where is the spleen located?
On the left side of the abdominal cavity below the diaphragm
What is the spleen comprised of?
Reticular cells (lymphatic tissue)
Red pulp (removes worn out platelets and RBCs)
White pulp (carries out immune function)
