BL S6 Phagocytosis, Complement And Oedema

Question 1

What are the 4 steps of phagocytosis?

Answer 1

Attachment
Phagosome formation
Phagolysosome formation
Lysis

Question 2

What occurs in attachment?

Answer 2

Adherence of bacterium to cell membrane through help of opsonins.

Question 3

What is an opsonin?

Answer 3

A molecule that binds to both antigen and macrophage enhancing the process of Phagocytosis.

Question 4

What is involved in phagosome formation?

Answer 4

Pseudopodia surround the bacterium, they fuse together surrounding the bacteria in a cell membrane called the phagosome.

Question 5

What is involved in phagolysosome formation?

Answer 5

Lysosomes fuse with phagosome.

Lysosomal enzymes discharged.

Question 6

What is involved in lysis?

Answer 6

Antimicrobial and cytotoxic substances produced by the phagocyte destroy the bacteria.

Question 7

What is opsonisation?

Answer 7

Process by which pathogens are coated with ABs marking them for phagocytosis by macrophages.

Question 8

What is Complement?

Answer 8

A group of serum protein that active 3 primary functions:

• Inflammation
• Opsonisation
• Membrane attack complex - lysis.

Question 9

What are the names of the 2 pathways the Complement cascade can be activated by?

Answer 9

Classical and alternative

Question 10

What is involved in the classical pathway?

Answer 10

C1 is activated when it binds to antigen-antibody complex.

Question 11

What is involved in the alternative pathway?

Answer 11

C3b activated when it reacts with antigens.

Question 12

Both pathways follow the same pathway post C3 true or false?

Answer 12

True

Question 13

What is oedema?

Answer 13

Accumulation of excessive water fluid in cells, tissues and serous cavities .

Question 14

What is Lymphoedema?

Answer 14

Swelling of mainly subcutaneous tissue as a result of obstruction of lymphatic and node, resulting in accusation of lymph in the affected region.

Question 15

Why does lymphoedema not pit?

Answer 15

Because proteins leak out from lymphatic vessels whereas in normal oedema no proteins accumulate.

Question 16

How does congestive heart failure lead to pulmonary oedema and peripheral oedema?

Answer 16

Cardiac output decreased
Less blood to kidneys
Kidney senses volume too low - retains more fluid.
Fluid increase results in back log of fluid in pulmonary vessels and this fluid leaks out into lung air spaces (alveoli etc).
Pitting oedema in legs caused by build up of fluid in the legs due to fluid leaking out from capillaries into interstitium.

Question 17

Why does oedema often first present at the ankles?

Answer 17

Gravity causes a vertical gradient of venous pressures with increased venous pressure at ankles.

Question 18

When prone oedema may present sacrally, true or false?

Answer 18

True.

Question 19

What is hypoproteinaemia?

Answer 19

Decreased level of serum proteins.

Question 20

How does oedema result from hypoproteinaemia?

Answer 20

Reduced oncotic pressure - vessels hold less fluid and leaks out into surrounding tissues and serous cavities.

Question 21

What is nephrotic syndrome and how can it cause hypoproteinaemia?

Answer 21

Increased permeability fo the bowmans capsule

Results in proteins passing though it - excreted in urine.

Question 22

Where may oedema be seen as a result of hypoproteinaemia?

Answer 22

Anywhere with lax skin.

Periorbital - around eyes
Scrotal sac and labia

Question 23

What is haemosiderin staining?

Answer 23

Yellow-brown pigmentation of the skin as a result of haemorrhaging of capillaries.
Erythrocytes leak out and as they die and breakdown iron in haem groups becomes oxidised and haemosiderin a rusty brown complex/.

Question 24

Why does left-sided heart failure have pulmonary implications?

Answer 24

Left atria are supplied by the pulmonary veins.

Back log in these will occur.

Question 25

What is primary Lymphoedema?

Answer 25

Hereditary Lymphoedema caused by a genetic developmental disorder affecting the lymphatic system.

Occurs due to obstruction, malformation or hypoplasia (underdevelopment) of lymph vessels.

Question 26

What is secondary lymphoedema caused by?

Answer 26

Damage to lymphatic system from surgery, radiation, therapy, trauma or infection.