Chp. 2 Cardinal Signs of Inflammation

Question 1

What are the cardinal signs of inflammation?

Answer 1

There are 5:

Redness (Rubor)
Warmth (Calor)
Swelling (Tumor)
Pain (Dolor)
Fever

Question 2

Redness and Warmth both are the result of what physiologic processes and mediators?

Answer 2

They are both due to vasodilation which results in increased blood flow.

This vasodilation (and therefore these cardinal signs) occur via relaxation of arteriolar s. muscle.

Key mediators are histamine, bradykinin, PGs.

Question 3

What is swelling due to and what are the mediators responsible for this?

Answer 3

Tumor or swelling is due to leakage of fluid from POSTCAPILLARY VENULES into the interstitial space (exudate)

Mediators are:

Histamine which causes endothelial cell contraction. This contraction “pulls apart” neighboring endothelial cells creating a space where stuff can leak out.

Tissue damage which results in endothelial cell disruption

Question 4

How is pain or dolor mediated?

Answer 4

It is mediated by bradykinin and PGE2 by sensitizing nerve endings

Question 5

How is fever mediated?

Answer 5

It starts with pyrogens (i.e. LPS from g- bacteria) that are recognized by TLRs on macrophages. Macros then release IL-1 and TNF.

IL-1 and TNF enter into the bloodstream, travel to the hypothalamus. It acts on the perivascular cells by increasing their COX activity. What does COX do?? It makes PGs. In particular, PGE2 which mediates FEEEEVER!! Basically the temp set point is raised.

Question 6

What are the two cytokines released from macrophages to induce fever?

Answer 6

IL-1 & TNF that act on perivascular cells in the hypothalamus by increasing COX activity