Cell Injury Stress

Foundations of Pathology 3032

Hans selye theory

General adaptation syndrome (Gas)

GAS

General: effect is general system reaction to entire body

Ex: Increase in heart rate, BP, hormone production

Adaptive: response in reaction to stressor

Syndrome: Physical manifestations were coordinated

Alarm stage

Fight or flight, occurs from SNS

Resistance stage

Body tries to defend, cortisol goes up

Exhaustion stage

Body gives up

Epinephrine gets

released into the blood as a response to fight or flight

Glucose fat and metabolism goes up as a

neuroendocrine response to stress (Cortisol)

Cortisol

Supresses inflammatory and immune responses

Epinephrine and Norepinephrine

Fight or flight, increases blood supply to muscle, may empty excretory organs and slow digestion

ORIGIN OF catecholamines (epinephrine and norepinephrine)

Adrenal medulla and brain

Corticotropin-releasing factor (CRF)

Messages pituitary gland to release adrenocorticotropic hormone (ACTH)

ORIGIN of corticotropin-releasing factor (CRF)

hypothalamus

Adrenocorticotropic Hormone (ACTH)

stimulates release of cortisol and aldosterone from adrenal cortex

ORIGIN OF Adrenocorticotropic Hormone (ACTH)

Pituitary gland

Antidiuretic hormone (ADH or Vasopressin)

Acts on kidney to retain water and causes blood pressure increase

ORIGIN of Antidiuretic hormone (ADH or Vasopressin)

Posterior pituitary

Cortisol

Stimulates glycogenolysis to increase blood glucose level, supresses inflammatory response

ORIGIN of Cortisol

Adrenal cortex

Aldosterone

Acts on kidney to retain sodium

Aldosterone ORIGIN

in adrenal cortex

HPA axis activated

by cytokines released from damaged cells and immune cells (T&B)

Hypothalamus is considered

the control center for the brain

Intracellular fluid (inside cell)

40% of body weight

Extracellular (outside cell)

20% of body weight, including interstitial, lymphatic and transcellular fluids

Intravascular fluid PLASMA INSIDE VASCULAR SYSTEM

5 % / 3.5 liters

Interstitial (BETWEEN CELLS+VESSELS)

14% / 10 liters

Lymphatic fluid inside lymphatic vessels and nodes

2% / 1.4 liters

Transcellular fluid (specialized compartments)

1% / 1 liter. Ex: pericardial, pleural, amniotic fluid

Osmosis

water from high concentration to low across semipermeable membrane

Isotonic tonicity

equal solute

ex: 0.9% normal saline

Hypotonic tonicity

Low solute shifts out (higher solute OUTSIDE cell)

Ex: 0.45% normal saline

Hypertonic

High solute concentration (shift into affected compartment)

Cells shrink, dehydrated

Ex: 3% normal saline

Venule (negative pressure)

Fluid moves into the venule

Arteriole (positive pressure)

Fluid forced into interstitial fluid (out of arteriole)

Endocytosis

move substances into cell thru cell membrane

Pinocytosis

cell drinking

phagocytosis

cell eating

Exocytosis

moving substances out of cell thru cell membrane

Proliferation

Cells make more cells through growth/division

Differentiation

Specialization of cells

Atrophy

decrease in cell size

• disuse

• denervation

• loss of endocrine stimulation (menopause)

• ischemia

• inadequate nutrition

hypertrophy

cells get bigger

hyperplasia

increase of # of cells

Two types of pathologic hypertrophy

Adaptive (work harder for ex: high bp heart works harder)

and compensatory (make up for ex: missing kidney)

metaplasia

One adult cell type is replaced by another adult cell type

Ex: smokers

Dysplasia

considered abnormal, can be reversed. DERANGED cell growth, varied SIZE SHAPE AND ORGANIZATION of cell

Ischemia

Not enough oxygen, not enough blood flow (heart attack)

Cellular swelling

Impairment of energy

Cells become hypoxic due to lack of oxygen

Fatty change

Intracellular accumulation of fat

excess amounts of fat in cell

cell unable to metabolize properly

Reversible cell injury causes

1. Freeradical injury

2. oxidative stress

   1. reaction oxygen species

Apoptosis

Programmed cell death, # of cells regulated by cell proliferation

Necrosis

Cell death in an organ or tissue still part of living person

Gangrene

when tissue undergoes necrosis

Wet gangrene LACK OF VENOUS BLOOD FLOW

INFECTED, liquidation, foul odor, rapid spread of damage

Dry gangrene LACK OF ARTERIOLE BLOOD SUPPLY

Tissue shrinks, wrinkly skin, slow spread

Gas gangrene LIFE THREATENING

Tissue dies very quickly, foul smell, gas bubbles,

May require amputation