Immune System and Lymph Flashcards
How do we make pathogens appear tasty?
Opsonisation
List 4 phagocytes.
Neutrophils, Eosoniphils, monocytes and macrophages
Outline the process of phagocytosis
Phagocytes are part of the innate immune response, they are cells that engulf pathogens. Once the foreign body is engulfed it’s said to have made a phagosome. The phagosome fuses with a lysosome to make a phagolysosome. This can break down the intruder.
There are two methods of chemical break down of pathogens in phagocytosis, what are they?
Oxygen dependent by reactive oxygen species
Oxygen independent by hydrolases
What is opsonisation?
Binding of opsonin to the bacteria marking it for phagocytosis.
What is opsonin?
A free floating plasma protein which is part of the innate and adaptive immune response.
What is complement?
Group of serum proteins involved in
Cell destruction
Inflammation
Opsonisation
What is the complement cascade?
The sequential manner in which complements respond.
How is complement activated?
2 pathways: classical or alternative
Classical- C1 activated when it binds to the antigen,antibody complex
Alternative- C3b is activated when it reacts directly with the antigen on the pathogen cell wall
At what point do the complement Cascades become the same independent of the activation being classical or alternative?
After C3
What’s the risk with low complement?
Increased risk of bacterial infection
Higher likelihood of autoimmune conditions
What is oedema?
An accumulation of excess fluid (watery) in cells, tissues and serous cavities
What’s lymphoedema?
Swelling in subcutaneous tissues as a result of damaged or obstructed lymphatic a or lymph nodes giving an accumulation of lymph in the region affected.
What type of oedema does not pit?
Lymph
Describe the sequence of vessel types in tissues?
Arteriole-metarteriole-through channel - arterial capillary- venous capillary-venule
What are lymphatic a closely associated with?
Capillary beds
What helps lymph return to the blood?
Thoracic pressure change
Skeletal muscle activity
Adjacent artery pulsation
What is the purpose of the pre capillary sphincter?
Control blood flow depending on activity
What happens in congested heart failure?
Both sides of the lungs stop working. Right side can’t cope with venous return so venous pressure increases. Left sided heart failure means you get a back up of pressure in the lungs.
If you have right sided heart failure where is the resulting oedema?
Peripheral
If you have left sided heart failure where is the associated oedema?
Lungs
Where is the right side of the heart receiving blood from?
The body
Where is the left side of the heart receiving blood from?
The lungs
High oncotic pressure in the veins means water will move…
In to the vessel of help dilate the hypertonic solution of the blood
High hydrostatic pressure in a vein will move water where?
Out of the vein or restrict resorption
Which pressure type varies from arteries to veins oncotic or hydrostatic?
Hydrostatic
What’s arterial and venous oncotic and hydrostatic pressures?
Artery hydrostatic: 35mmHg
Venous hydrostatic : 15mmHg
Colloid oncotic pressure : 25mmHg
What leaves the blood in tissues at capillary beds?
Oxygen, nutrients and glucose as well as some water
What moves into capillaries ?
Carbon dioxide, waste and resorption of water as hydrostatic pressure in veins drop
Why does high venous pressure become most apparent in the ankles?
Vertical pressure gradient in standing patients. Supine patients will suffer sacral oedema
If swelling appears during the day in the ankles what type of oedema is it likely to be?
Peripheral oedema not due to lymphatics
Unilateral ankle swelling through the day suggest what type of aetiology?
Localised not a systemic or heart failure related problem
In hyperproteinaemic patients where there is nephrotic syndrome why is oedema seen around the eyes in the morning?
Lying down the eyes are higher so verticals pressure gradient allows the fluid to accumulate there
Which oedema causes inflammatory fibrotic changes?
Lymphoedema
Is there an absence of lymphoedema in the morning.
No
Why do heart failure patients have discoloured legs.
Poor venous return to heart so capillaries burst and erythrocytes discolour the tissue as they leak out
Which is darker fe2+ or fe3+
Fe3+
