Cellular Injury, Adaptation, and the Integumentary System

types of cell adaptation

atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia

atrophy

decrease in cell size due to decreased workload, stimulation, and nutrition

hypertrophy

increase in cell size due to increased workload

physiological hypertrophy

muscle cells enlarging due to increased workload

pathological hypertrophy

cardiac muscle enlargement in left ventricle due to increased blood pressure

hyperplasia

increase in number of cells in response to a stimulus

physiological hyperplasia

increase in breast tissue during pregnancy

metaplasia

replacement of one mature cell with a distinctly different cell due to chronic irritation/inflammation

dysplasia

abnormal growth of cells resulting in varying size, shape, and type; precancerous

determinants of cell injury

intensity/duration of stimulus, type of cell damaged, blood/nutrition supply, regenerative capacity

cellular injury categories

physical agents, radiation, chemical, biological agents, nutrition imbalance

mechanical injury types

abrasion, contusions, lacerations, punctures

abrasions

irritation/damage to surface-level tissues

contusions

bruises

lacerations

large shallow cut of the skin

puntures

small deep cut of the skin

types of physical agent injuries

mechanical, thermal, electrical

rule of nines

a method used in calculating body surface area affected by burns

direct radiation injury

ionization of molecules of cell organelles leading to cell death

indirect radiation injury

produces free radicals that cause genetic disruption

apoptosis

programmed cell death

necrosis

abnormal tissue death not supplemented with tissue regeneration

cell types in the epidermis

keratinocytes, melanocytes, langerhans cells, merkel cells

Langerhans cells

epidermal macrophages that help activate the immune system

Merkel cells

deep pressure epidurmal sensors

epidermal layer superficial to deep

stratum corneum, lucidum, granulosum, spinosum, basale

epidermal layer only found in palms and soles

stratum lucidum

superficial layer of the dermis

papillary

deep layer of the dermis

reticular

Meissner's corpuscles

light touch receptors

pacinian corpuscles

pressure receptors

free nerve endings

pain, itch, tickle, and temperature receptors

root hair plexus

touch perception of hair

ruffini corpuscles

stretch and pressure sensors

Decubitis ulcers

injury to tissue due to prolonged pressure/compression of the integumentary system

stage 1 decubiti

intact erythematous epidermis

stage 2 decubiti

broken epidermis/dermis with blistering or shallow open wounds

stage 3 decubiti

down to subcutaneous tissue

stage 4 decubiti

wound extending to underlying msucle/bone

deep tissue injury

intact dermis but bruised appearance and mushy feel

unstageable injury

when the injured area is covered with blackened and leathery tissue

contractures

chronic loss of joint mobility caused by structural changes in non-bony tissue

most common cause of contractures

immobility