Fluid compartments, Lymph and drainage Flashcards
What does the lymphatic system do?
Drain the interstitial fluid lost from capillary beds as well as pathogens, WBC, hormones and debris from broken cells/microbes back into the vascular system.
What are the lymphatic vessels that transport fat from the small intestine, and what is the fluid called?
Lacteals, chyle
Where does lymph and chyle end up before returning into venous circulation?
Cisterna Chyli, then thoracic duct
Where is the left venous angle?
Junction between the left internal jugular vein and the left subclavian vein.
Where does the thoracic duct attach to the vascular system?
Left venous angle
Where does lymph from the right upper limb, right thorax and right head & neck drain to and connect with the vascular system?
Right lymphatic duct, right venous angle
What is contained within the lymph nodes?
WBC (lymphocytes and macrophages)
Describe the difference between afferent and efferent lymph vessels
Afferent=draining into node
Efferent=draining away from node
What is the term for enlarged lymph nodes?
Lymphadenopathy
Where are metastatic cells from a breast cancer tumour likely to spread first?
Axillary nodes
Which lymph node is most likely to metastasise from a primary testicular cancer tumour?
Lateral aortic
What are the lymph nodes in the axilla?
Pectoral, subscapular, humeral, central and apical
Bone marrow is which type of lymphatic tissue?
Primary
Lymph nodes are which type of lymphatic tissue?
Secondary
What is the ratio of ICF to ECF?
2/3 ICF to 1/3 ECF
What is ECF made up of?
Interstitial fluid and plasma
Where is K+ most abundant?
Intracellular fluid
Where is Na+ most abundant?
Extracellular fluid
Is oncotic pressure higher in plasma or interstitial fluid?
Plasma, because of the proteins
Oedema is caused by an increase in which fluid compartment?
Interstitial
What two forces promote reabsorption of fluid into the vessels?
Oncotic pressure and interstitial hydrostatic pressure
Which forces promote the movement of fluid into the interstitium?
Capillary hydrostatic pressure and interstitial osmotic pressure
Where is capillary hydrostatic pressure highest?
At the arterial end of the capillary
How much lymph fluid is formed daily under normal conditions?
3L
What is net filtration pressure?
The sum of filtration forces minus reabsorption forces
Under normal conditions, net filtration pressure is negative at which end of the capillary? What does this mean?
Venous, net fluid is moving into the vessel
Under normal conditions, net filtration pressure is positive at which end of the capillary? What does this mean?
Arterial, net fluid is moving out of the vessel into the interstitium
What is meant by the TRUE net filtration pressure?
Multiplied by Kf coefficient which factors in the permeability and surface area of the capillaries
What is the most abundant type of capillary?
Continuous
Where would you find fenestrated capillaries?
Small intestine
What are the two types of fluid that can accumulate in oedema? Explain the difference between them.
Transudate- low protein
Exudate- high protein
What type of fluid would you see in oedema caused by infection and inflammation?
Exudative
Intracellular oedema is primarily caused by what mechanism?
Impaired sodium-potassium pump = cellular swelling
What might the body do to reduce oedema?
Increase lymphatic flow
What part of the net filtration pressure formula would sepsis affect? What affect would this have?
Capillary coefficient (Kf) because there would be increased permeability. Increase in flow out of the vessels = oedema
How would a DVT cause oedema?
Blood cannot get past the clot = pools in lower limb.
Increased capillary hydrostatic pressure = oedema
Briefly explain congestion in HF
Poor cardiac output leads to poor renal perfusion causing sympathetic activation. Renin-angiotensin- aldosterone system increases retention of sodium and water. Increased blood volume increases capillary hydrostatic pressure which causes fluid to move into the interstitium.
What provides a quick compensatory mechanism for the reduced cardiac output of HF?
Reduced cardiac output = reduced capillary hydrostatic pressure = fluid moves out of interstitial fluid store to increase blood volume and pre-load.
Left sided HF can cause what life-threatening pathology?
Pulmonary oedema
What side of the heart is involved in peripheral oedema?
Right ventricular failure results in back up of the systemic circulation. However, most commonly, left sided HF comes first and leads to right sided HF.
