BHS 329 Unit 3

What are the three major goals of acute inflammatory response

1. Vascular response (increase blood flow)

2. Cellular response (alert the products of healing to attend site of injury)

3. Remove injured tissue and prepare site for repair and healing

What are the three lines of defense?

1. Skin and mucous membranes

2. Inflammatory response

3. Immune response

Which line of defense is nonspecific

The inflammatory response

Which line of defense is specific?

The immune response

What two vascular changes occur during inflammation?

Vasodilation and increased capillary permeability

Why does vasodilation occur

To increase blood flow to injured tissue

Why does vascular permeability increase

To allow leukocytes and plasma proteins into tissues

What is exudate

Protein-rich inflammatory fluid that leaks into tissues

Which cell releases histamine immediately after injury

Mast cells

Process by which mast cells release mediators?

Degranulation

Major inflammatory mediators

1. Histamine

2. Prostaglandins

3. Leukotrienes

4. Cytokines

5. Serotonin

6. Platelet-activating factor

Histamine causes what?

Vasodilation and increased vascular permeability

Which inflammatory mediators are produced from arachidonic acid?

Prostaglandins

Leukotrienes

Thromboxane

Lipoxins

Which drugs block arachidonic acid production

Corticosteroids

Three plasma protein systems?

Complement, clotting, kinin

Function of complement system?

Network of small proteins that complement the ability off immune cells to fight off infections and destroy microorganisms.

What is the function of clotting system?

Stops blood loss, protects wound from infection, and provides a structural framework for the body to begin tissue repair

Function of kinin system?

Upon activation, releases potent vasoactive peptides which cause blood vessels to dilate and increase vascular permeability

What are the three steps of the cellular response

1. Chemotaxis

2. Cellular adherence

   1. Cellular migration (diapedesis)

What is chemotaxis

the calling forth of inflammatory cells to injured sites

What is diapedesis

white blood cells (leukocytes) move through the intact walls of blood vessels into surrounding tissue, allowing these cells to reach and fight infection

What is phagocytosis

Engulfment and destruction of harmful substances

What is the first leukocyte to arrive?

Neutrophils are the first leukocytes to arrive at the site of inflammation, often referred to as the “first responders”

Which cells dominate chronic inflammation?

Macrophages, lymphocytes, and plasma cells

Which cells are more prevalent in acute inflammation

Neutrophils

What do monocytes become?

Monocytes can differentiate into macrophages or dendritic cells when they migrate into tissues

What is the function of a macrophage

Phagocytosis, cytokine release, present antigens to T cells

What is the function of a monocyte?

located within blood and is a precursor to macrophages

Function of platelets

To stop bleeding by forming blood clots (hemostasis), release inflammatory mediators

Five cardinal signs of inflammation

Redness, heat, swelling, pain, loss of function

What is the cause of redness

Vasodilation increases blood flow to injured area

What is the cause of swelling

Increased vascular permeability

What is the cause of pain?

Tissue swelling puts pressure on nearby nerves and inflammatory chemicals stimulate pain receptors

What is the cause of heat?

Vasodilation brings warm blood to the area

What are some common systemic manifestations related to the inflammatory response?

Fever, leukocytosis (increased WBC count), and increased acute-phase proteins

Why does fever occur?

inflammatory cytokines (especially IL-1, IL-6, and TNF-α) act on the hypothalamus (body thermostat), raising the body's temperature set point.

What is leukocytosis

Elevated WBC count (>10,000//mm³)

What is the best marker of acute inflammation?

C-reactive protein (CRP) because it is an acute-phase protein that rises rapidly in response to inflammation.

What does ESR measure?

measures the rate at which red blood cells settle in a tube; a faster sedimentation rate indicates the presence of inflammation due to increased acute-phase proteins such as fibrinogen.

extended inflammation

What does an elevated CRP indicate?

Current, active inflammation.

What is the initial non-drug treatment of acute inflammation

RICE

Rest
Ice

Compression

Elevation

What does rest do?

Prevents further injury and gives damaged tissue time to heal.

What does ice do?

Causes vasoconstriction, which reduces blood flow, swelling, inflammation, and pain.

What does compression do?

Applies pressure to limit fluid leakage into the tissues, reducing edema (swelling).

What is elevation do

Raises the injured area above the level of the heart, allowing gravity to improve venous and lymphatic drainage, reducing swelling.

NSAIDs decrease inflammation, pain, and fever by blocking __________

No Synthesis of Prostaglandin

What are some examples of NSAIDs

Ibuprofen, naproxen, aspirin

Corticosteroids decrease inflammation by

blocking the production of arachidonic acid, thereby decreasing the inflammatory response

What are the three phases of healing?

Inflammatory, proliferative, and remodeling

What is the inflammatory phase of healing?

stop bleeding and cover the wound

What is the proliferative phase of healing?

Clean the debris and restore structural integrity

What is the remodeling phase of healing?

Restore functional integrity and remodeling

What is the purpose of a fibrin clot

Stop bleeding from an injured blood vessel and protect the wound

Why shouldn’t you pick a scab?

Forces your body to restart the healing process and there is an increased risk for infection

What are the two major ECM structures?

Basement membrane and connective tissue

What must happen before reepithelialization can occur?

The basement membrane must be restored.

Which cell produces collagen?

Fibroblasts

What does excess collagen cause?

Fibrosis and keloids

Which immune cell stimulates fibroblasts?

Macrophages

What are the three methods of tissue healing?

Resolution
Regeneration
Replacement (scar formation)

What is resolution?

Healing after minor injury with. minimal tissue damage

- rapid healing, little or no scarring, tissue returns to normal

What is regeneration

Replacement of damaged tissue by new functional cells through mitosis

occurs by cell proliferation, differentiation, cell migration (diapedesis)

Which cells regenerate continuously?

Labile cells.

examples: skin epithelium, GI tract, urinary tract, bone marrow

Which cells regenerate only after injury?

Stable cells

e.g. hepatocytes (liver)

Which cells cannot regenerate?

Permanent cells.

e.g. neurons, cardiac muscle, lens of the eye

What is replacement

Healing by scar tissue (fibrosis) when regeneration is impossible

What is reepithelialization

Basal epithelial cells divide and migrate across a wound until skin is restored

What is granulation tissue?

Temporary healing tissue composed of

fibroblasts, macrophages, new capillaries (angiogenesis). supports wound healing

What is angiogenesis

Formation of new blood vessels during healing. The purpose s oxygen delivery, nutrient supply, and waste removal

What is primary intention healing

• minimal scar, low infection risk, wound edges together, fast healing
  
  e.g. surgical incision

What is secondary intention healing

Large open wound, heals from bottom upward, slow, large scar, higher infection risk

What are the nutrients most important for wound healing

Protein, vitamin A, vitamin C, water, adequate blood flow

What are some cmon wound healing complications

Infection
Ulceration
Dehiscence

Keloids
Adhesions

What is wound dehiscence?

Wound splits open due to poor collagen formation

What is a keloid

Excessive collagen deposition resulting in raised scar

Common in: darker skin, ages 10-30, familial tendency

What are adhesions?

Fibrous bands joining organs together after injury or surgery

What is chronic inflammation

Inflammation lasting weeks to months because the cause persists

What are the main causes of chronic inflammation

Persistent infection, autoimmune disease, foreign body

What are the major cells of chronic inflammation

Macrophages, monocytes, lymphocytes

What is the role of macrophages in chronic inflammation

They produce proteinases → tissue destruction
They produce fibroblasts → fibrosis

What is fibrosis

Excess collagen deposition causing scar formation, permanent loss of function

What is a granuloma

Tiny, organized cluster of white blood cells. Typically form when the injury is too difficult to control.

e.g. tuberculosis

Giant cells vs epithelial cells

Giant cells: engulf large particles
Epithelioid cells: form fibrous wall around irritants

What is the duration of acute sinusitis duration

4-8 weeks

What is the duration for chronic sinusitis duration

Greater than 12 weeks

What are some common causes of sinusitis

Viral infection, allergies, impaired mucus drainage, blocked ostia

Clinical manifestations for acute sinusitis

Facial pain over the sinus regions of the face increasing with straining or bending down

Fever

Nasal congestion or excessive nasal discharge

Persistent cough

Fatigue

Clinical manifestations for chronic sinusitis

Nasal congestion, chronic cough, hyposmia, postnasal drip, fatigue

What are the three classifications of burns

Superficial partial thickness (1st degree)
Deep partial thickness (2nd degree)
Full-thickness (3rd degree)

What are the characteristics of Superficial Partial Thickness (1st Degree)

• Epidermis only

• Painful

• Red

• No blisters

  • No scar

What are the characteristics of Deep Partial-Thickness (2nd degree)

• Epidermis + dermis

• Blisters

• Pain

• Edema

• Possible scarring

What are the characteristics of Full-Thickness (3rd degree)

• Entire skin destroyed

• White/black eschar

  • No pain in burned center W

• Extensive scarring

• Skin graft required

Erythema, eschar formation, edema, and exudate characterize ___-______ ______

full thickness burns

What is eschar

Thick necrotic crust over a full-thickness burn

What is debridement?

Removal of dead tissue from a wound

Rules of Nines is used for

Estimating percentage of body surface burned

What causes rheumatoid arthritis?

Autoimmune attack against synovial tissue

Main inflammatory cells in rheumatoid arthritis

CD4 T-cells
Plasma cells

Macrophages
Lymphocytes

What is pannus

Granulation tissue that grows over cartilage, destroying cartilage and bone

What is ankylosis

Joint fixation due to fibrosis