cell adaptation cell injury

Tanveer Tara ,Lecture MLT , SUIR
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Cellular adaptation
Adaptation
The process of change by which an organism or species
becomes better suited to its environment.
Cellular adaptation
In cell biology and pathophysiology, cellular
adaptation refers to changes made by a cell in response to
adverse environmental changes. The adaptation may be
physiologic(al) (normal) or pathologic(al) (abnormal). Five
minor types of adaptation include atrophy, hypertrophy,
hyperplasia, dysplasia, and metaplasia
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Cell
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CELL Biology
Cell has three components.
Cytoplasm ,Cell membrane , nucleus
In cytoplasm there are some organelles which have
some various function these are
Mitochondria
Power house of the cell.
Ribosomes
Synthesize protein in the cell
Lysosome
Intracellular digestion and removed unwanted substances.
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CELL Biology
Endoplasmic reticulum
Detoxifies the damaging substance to the cell.
Cell Membrane.
It maintain fluid ,ionic balance and provide pathway for
controlled transport of various substances.
Nucleus.
Control center of the cell and composed of DNA.
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Adaption
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Cellular adaptation
In cell biology and Pathology cellular adaption refers to
change made by a cell in response to adverse
Environmental changes.
Adaptation is basically an adjustment of the cell of the
cell with in limits to the environment in which altered
steady state is achieved to preserve the viability of the
cell despite continued stress.
Stress may physiological or pathologic stimuli,
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Examples of Cellular adaptation
Hypertrophy
Atrophy
Hyperplasia
Metaplasia
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Plasia means cellular multiplication

Hypertrophy
(excessive nourishment)
Hypertrophy is an increase in cell size or organ or tissue
due to increase in the size of the cell.
In hypertrophy there is no new cell , just bigger cells
containing increased amounts of structural proteins and
organelles. Number of cell remain the same
The heart and kidneys have increased susceptibility to
hypertrophy.
An example of physiologic hypertrophy is in skeletal
muscle with sustained weight bearing exercise.
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Hypertrophy can be Physiological
and Pathological
Massive physiological enlargement of the uterus and Breast
during pregnancy occur as a consequence of estrogen
stimulated smooth muscles hypertrophy .
An example of pathologic hypertrophy is in cardiac muscle as
a result of hypertension or aortic valve disease.
Enlargement of left ventricle in hypertensive Heart disease.
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Hypertrophy
 Hypertrophy refers
to an increase in
muscular size
achieved through
exercise. When you
work out, if you want
to tone or improve
muscle definition,
lifting weights is the
most common way to
increase hypertroph
y
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Breast Hypertrophy
 During pregnancy, rising
hormone levels signal the
glands in your breasts
to grow to prepare for milk
production. You're also gaining
weight to support
your growing pregnancy, and
there's that blood-volume
boost, too. All these factors can
translate into bigger breasts
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Uterine Hypertrophy
 Hypertrophy in the uterus can
involve
the endometrial epithelium
and/or the myometrial smooth
muscle cells.
... Physiologic epithelial hypertro
phy can occur in response to
increased circulating estrogen
levels during the estrous cycle.
Compounds that have estrogenic
activity can induce
epithelial hypertrophy in
the uterus.
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Hypertrophy
in Heart
 During pregnancy,
healthy women
develop
ventricular hypertrop
hy and diastolic
dysfunction as a
result of volume
overload as well as
increased stretch and
force demand.
.
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16 Atrophy: is a decrease in cell size or shrinkage in
the size of the cell by the loss of cell substances is
known as atrophy

Causes of atrophy
Decreased workload( e.g immobilization of a
limb to permit healing of a fracture)
Loss of innervation
Diminished blood supply
Inadequate nutrition
Loss of endocrine stimulation
Aging(loss of teeth, hair, thinning of skin that
creates wrinkles, weakening of muscles, loss of
weight in organs and sluggish mental activity)
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Atrophy
Some stimulus are physiologic (e.g
loss of hormone stimulation in
menopause due to decrease level of
estrogen hormones and then shut
down the reproductive system.
Atrophy of the breasts can occur with
Prolonged estrogen reduction, as
with menopause.
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Testicular atrophy
Testicular atrophy is a medical
condition in which the male
reproductive organs (the
testes, which in humans are
located in the scrotum)
diminish in size and may be
accompanied by loss of
function. with prolonged use
of enough exogenous sex
steroid
(either androgen or estroge
n) to
reduce gonadotropin secret
ion.
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Vaginal atrophy
 Vaginal atrophy is
thinning, drying and
inflammation of
the vaginal walls that
may occur when your
body has less
estrogen. Vaginal
atrophy occurs most
often after menopause.
For many
women, vaginal
atrophy not only makes
intercourse painful but
also leads to distressing
urinary symptoms.
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Penis Atrophy
 As men age, fatty deposits build up
in the arteries causing reduced
blood flow to the penis. This
results in the muscle cells in the
erectile tubes inside
the penis becoming weaker. ... This
accumulation of scar tissue affects
the spongy erectile tissues of
the penis, causes penis shrinkage,
and limits erection size.
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Mechanism of atrophy
Atrophy mechanism consist of a combination of
decrease protein synthesis and increased protein
degradation in cell.
Protein synthesis decrease b/c of reduced metabolic
activity.
In many situations , atrophy is also accompanied by
increase autophagy,.
Autophagy (self eating) is the process in which the
starved cell eats its own components in an attempt to
survive.
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Hyperplasia
Hyperplasia is an increase in the number of cells which
result increase the size of an organ.
It is the result of increased cell mitosis, or division .
Hyperplasia can be physiological or pathological.
.
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Endometric Hyperplasia
Pathologic
hyperplasia is an
abnormal increase in
cell division.
A common
pathologic
hyperplasia in women
occurs in
the endometrium and
is
called endometriosis.
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Prostatic hyperplasia
Enlargement of
the prostate is called
benign prostatic
hyperplasia (BPH). It
occurs when the cells of
the prostate gland begin
to multiply. These
additional
cells cause your prostate
gland to swell, which
squeezes the urethra
and limits the flow of
urine
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vaginal hyperplasia,
 vaginal hyperplasia, a
proliferation of
the vaginal mucosa, usually
originating from the floor of
the vagina anterior to the
urethral orifice, occurs during
proestrus and estrus as a
result of estrogenic
stimulation. Occasionally,
the prolapse continues
throughout pregnancy or
recurs at parturition.
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Sebaceous hyperplasia
 In this condition, small
yellowish growths
develop on the skin,
usually on the face. This
condition is neither
contagious nor
dangerous.
For example, the
estrogen-dependent
uterine cells undergo
hyperplasia and
hypertrophy following
pregnancy.
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Penile shaft
 Sebaceous hyperplasia of the
scrotum and penile shaft.
... Sebaceous hyperplasia (SH)
is a proliferative abnormality
of sebaceous glands, most
often seen in elderly
individuals. It consists of single
or multiple, asymptomatic,
small yellow papules with a
central depression.
https://www.ncbi.nlm.nih.gov/pubmed/22
346273
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Metaplasia : "change in form")
A Reversible change in cell structure from one fully
differentiated from to another in response to a normal
abnormal stimuli
In simplistic terms, it is as if the original cells are not
robust (STRONG)enough to withstand the new
environment, and so they change into another type
suited to the new environment.
If the stimulus that caused metaplasia is removed or
ceases, tissues return to their normal pattern of
differentiation.
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Metaplasia
 Metaplasia is the conversion from one type of normal
adult cell to another type of normal adult cell. ... An
example of physiologic metaplasia is the
 squamous metaplasia that occurs in the uterine cervix
during the menstrual cycle as the squamocolumnar
junction migrates across the transformation zone
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Types
 Physiological : A normal type of cell maturation
 Pathological : A Change due to abnormal stimulus
Example of Physiological Metaplasia
Metaplasia of endocervix ( Columnar epithelium to squamous
epithelium)
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These transformed cells may become dysplastic or cancerous
if the stimulus (e.g., cigarette smoking) is not Stop.
If stress persists, metaplasia can progress to dysplasia and
eventually carcinoma;
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Metaplasia in
their trachea
 Smokers undergo metaplasia in
their trachea where the
epithelum changes from a
columnar (or column-like) to a
squamous (or pancake-like)
one. People who have
conditions such as reflux
esophagitis will
have metaplasia in the
esophagus where the
epithelium changes from
stratified squamous (stack of
pancakes) to columnar.
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38 Tanveer Tara ,Lecture MLT , SUIR

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APLASIA vs Hypolasia
is that hypoplasia is
underdevelopment or incomplete
development of a tissue or organ,
especially when caused by an
inadequate or below-normal number
of cells while aplasia is (pathology) a
condition marked by the incomplete
development, or absence, of an organ
or tissue.
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THANK YOU
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cell adaptation cell injury

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