Module 4 - lecture 6/7 Flashcards
Parenchymal cells
Functional cells of the organ
Stromal cells
Supporting structures of organs
Tissue regeneration
Replacement of injured tissue with cells of the same type and function
Tissue repair
Occurs when extent or nature of damage cannot be reversed by regeneration alone (scar)
Stages of healing after tissue injury
Hemostasis (minutes), Inflammation (hours), Proliferation (days), Remodeling (weeks to months)
Hemostasis (minutes)
Local vasoconstriction and activation of platelets and clotting factors to form a fibrin clot, creates the scaffold for migrating cells
Inflammation (hours)
Driven by platelet derived mediators, bacteria, and secreted chemoattractants
Proliferation (days)
Mediated by macrophage and fibroblast derived growth factors
Remodeling (weeks to months)
transition from type 3 to type 1 collagen restoring tensile strength of tissue
Determinants of regeneration vs repair
Nature of cells injured, extent of injury, presence or absence of ongoing inflammation, underlying disease
Common outcome of various signal transduction pathways of growth factors
change in gene expression
Primary intention
wound closed
Secondary intention
wound left open
tertiary intention
delayed primary closure
Mechanism regulating cell proliferation
Differentiation, population, apoptosis
Epidermal growth factor source
Activated macrophages, keratinocytes
Epidermal growth factor function
Mitogenic for keratinocytes and fibroblasts, simulates keratinocyte migration and granulation tissue formation
ECM Basement membrane components
Type IV collagen, laminin, proteoglycan
EXM interstitial matrix components
Fibrillar collagens, elastin, proteoglycan and hyaluronan
fibrosis definition
scarring
4 processes of fibrosis
Angiogenesis, migration proliferation, deposition of ECM, maturation by macrophages
Growth factors that regulate fibrosis
PDGF, TGFBeta, FGF-2
Three key elements of shock
Life threatening, circulatory failure, inadequate oxygenation
Four types of shock
Distributive, Hypovolemic, Cardiogenic, Obstructive
Distributive shock
Vasodilation, sepsis #1, anaphylaxis, neurogenic
Septic shock mortality rate
25-50%
70% of septic shock cases caused by
endotoxin producing gram negative bacillus
Hypovolemic shock
loss of plasma or blood volume
hypovolemic shock causes
hemorrhage(ectopic pregnancy), severe burns, severe vomiting diarrhea
Cardiogenic shock
Myocardial infract, ventricular arrhythmia, cardiac myopathy, valvular disease
Obstructive shock
characterized by a blockage flow caused by a massive pericardial effusion, cardiac tamponade, pneumothorax
Gram negative bacteria
endotoxin lipid A, o antigen on outer membrane
Adrenomedullin role
enhances endothelial barrier function, acts differently in vascular space vs interstitial space
Edema definition
Accumulation of fluid in interstitial space of body tissues
Primary drivers of fluid in and out of vascular space
Hydrostatic pressure (pushing fluid out), colloid osmotic pressure (drawing fluid in)
Cause of edema
Inability to reabsorb or remove fluid from lymph, leading to fluid accumulation
Increased capillary permeability
L: cellulitis S: sepsis, hypersensitivity
Increased capillary hydrostatic pressure
L: compartment syndrome, chronic venous insufficiency S: heart failure, renal failure, pregnancy
Decreased capillary oncotic pressure
S: protein deficient states (nephrotic syndrome, cirrhosis)
Lymphatic obstruction lymphedema
L: tumor, trauma, infection (filariasis)
Transudate
protein poor
exudate
protein rich
Drug induced edema causes
Lymphatic drainage disruption, increased capillary permeability, increased capillary hydrostatic pressure
