Lymphatic System Flashcards
Function of the Lymphatic System
Maintains fluid levels in the body by draining lymph (which contains tissue fluid and fats) back into the blood.
Capillary bed
A network of capillaries and the surrounding tissue, this is where tissue fluid is formed
What is tissue fluid?
A watery substance which is forced out of the capillaries and provides substance exchange for cells
Such as providing gases and nutrients and removing waste products
What is found in tissue fluid?
Water
Dissolved minerals and salt
Glucose
Small proteins & amino acids
Fatty acids
Ions
Oxygen
Formation of tissue fluid
Blood flowing from arterioless into capillaries has a high blood pressure and therefore high hydrostatic pressure
This causes blood fluid to be forced out of the gaps in capillaries
The fluid moves out & bathes surrounding tissue (now called tissue fluid)
What doesn’t leave the capillaries?
Red blood cells
Platelets
Large proteins
Because they’re too large to leave the gaps in capillaries
What waste products are found in tissue fluid?
Urea
Carbon Dioxide
The venule end
Has a low water potential because large molecules are still in the capillaries
Has a low hydrostatic pressure as there is less fluid
Reabsorption of tissue fluid
Low water potential and hydrostatic pressure in venule end
This causes water and dissolved substances to move back into the capillaries by osmosis
Until an equilibrium is reached
What happens to excess tissue fluid?
Once an equilibrium is met, there will still be tissue fluid present
This is drained into lymph vessels and eventually drained back into the blood (around the heart)
Lymph
The name given to excess tissue fluid when it enters the lymphatic system
Lymphatic system
System of lymph vessels which surround blood vessels
To join back up with blood vessels near the heart and passively drain lymph into the bloodstream
Lymph Vessels
Vessels which are similar to veins
They surround blood vessels & contain valves to prevent the back flow of lymph
Pumping in the Lymphatic System
Relies on movement and muscle contraction to pump lymph to near the heart/neck area where it can be drained back into the blood
What happens if there’s a period of time with no movement?
Lymph build up around the ankles and causes swelling.
This is because it can no longer be pumped and will therefore be pulled down around the ankles by gravity.
