2 Mechanism of Defense & Repair: Cellular Response

why do wbc leave blood [2]

1) increase vascular permeability = slower blood flow

2) WBC respond to distress signals

Margination

WBC moves to the margin/edge of vessel + sticks/rolls along endothelium 

Diapedesis

WBC squeezes through the gap 

Emigration

WBC moves out of blood → tissue 

Injured cells release: 

• Cytokines 

  • Chemokines 

Main Functions of WBCs  [2]

Phagocytosis; WBC eats/engulfs and destroys microbes, cell debris

apoptosis: programmed cell death: wbc release perforin that destroy targeted cell

what do platelets response to [2]

dcrease blood flow [caused by increase of vasculr permeability]

damage endothelial cells: platelet interact w collagen [platelets activated]

platelets respond to what

tissue damage

after platelet respond to tissue damage what does it start

hemostasis

3 blood clot components

platelet, sticky fibrin thread, rbc’s in fibrin

Thrombus

intravascular blood clot

Blood clot

extravascular clot 

3 steps of platelet plug formation

1. platelet adhesion - stick

2. platelet release rxn - get sticky

3. plately aggregation - clump

in platelet release rxn, what do platelets release chemicals that make them larger and sticky

• PDGF 

• Serotonin 

• Thromboxane A₂ 

  • ADP

what do rbc respond to [2]

1. ↓ Blood flow 

   1. Platelet activation 

why is there a decrease in blood flow of rbc

• Caused by ↑ venule vascular permeability 

  • blood is thicker and slower

Rouleaux

RBCs stack together

Extravasation

blood cells leave the vessel 

plasmin

break down fibrin clot

what is the chemical released when tissue gets damaged [acute inflammatory response]

histamine

histamine does what 3 things

vasodilation

increases vascular permeability

help wbc’s enter

what happens other blood as fluid gets released from it

gets thicker and concentrated

Pro-inflammatory mediators

chemicals that START or INCREASE inflammation

what does CAM stand for and what does it do for WBC

cell adhesion molecule

help wbc stick to vessel wall + leave blood → tissue