Pathological morphology - adaptive, compensatory & regenerative processes Flashcards
Adaptation is
a biological concept that comprises all the processes of a living organism and its mutual communication with the external environment.
Compensation is
a form of adaptation and takes place when a disturbance of an organ or tissue is balanced by appropriate changes in its structure.
Regeneration is
the natural renewal of dead or harmed tissues, through proliferation of cells in the parts of tissues that have survived.
hypogenesis/agenesis
underdevelopment of an organ or function, during the period of embryogenesis
hypoplasia/aplasia
refers to a lack of cells in an organ or tissue (after birth)
difference between hypertrophy and hyperplasia
Hypertrophy refers to an increase in the size of individual cells/muscle fibers, whereas hyperplasia refers to an increase in the number of cells/muscle fibers.
atrophy definition and causes
Definition: wasting or decrease in size of a body organ, tissue, or part. Shrinkage in cell size by loss of cell substance.
Causes:
Reduced workload
Loss of innervation
Reduced blood supply
Inadequate nutrition
Loss of endocrine stimulation
Ageing
Grossly, atrophied organs have
a decreased weight and volume,
may have a loose covering membrane,
have tortuous blood vessels too large for the volume of tissue, and
often are firmer because of fibrosis.
Microscopically, cells of atrophied tissues are
smaller and/or reduced in number,
decreasing amount of cytoplasm,
cell nucleus is in normal size.
name different types of atrophy
simple atrophy
compression atrophy
brown atrophy
excessive activity atrophy
neurogenic or neurotrophic atrophy
simple atrophy is
reduction of an organ, one cell type.
compression atrophy is
caused by long-term mechanical pressure
brown atrophy is
reduction of an organ and accumulation of yellowish brown pigment lipofuscin, which makes the atrophic organs brown in colour.
excessive activity atrophy occurs
mainly with work animals, who are exploited excessively
neurogenic or neurotrophic atrophy occurs when
innervation stops, for example due to a nerve being cut.
causes of hypertrophy (2+3)
Occurs in permanent cells, is due to synthesis of more cellular structural components.
Physiological causes:
Increased functional demand, e.g. skeletal muscle (mechanical)
Hormonal, e.g. uterus in pregnancy (usually a combination of hypertrophy and hyperplasia)
Pathological causes:
Increased functional demand e.g. cardiac muscle
Hypertension
Valvular heart disease
Microscopically, hypertrophic cells are
bigger than normal, nucleus is normal size.
Hyperplasia causes (2 + 1)
Hyperplasia can only occur in tissues containing labile(dividing) or stable cells.
Physiological hyperplasia causes:
Hormonal e.g. endometrium
Compensatory, e.g. partial hepatectomy
Pathological hyperplasia causes:
Excessive hormone/growth factor stimulation
(Often occurs alongside hypertrophy
Associated with increased risk for cancer
E.g. Prostate, endometrium)
statmokinesis
an anomaly of mitosis, the stopping of mitosis
typically results in cell death
multipolar mitosis is what and results in what
Abberant mitotic figures, where the chromosomal material is pulled to more than two poles.
may result in giant cell formation
aneuploid
having an abnormal number of chromosomes in a haploid set (= single set of chromosomes)
what is a giant cell
(also known as a multinucleated giant cell, or multinucleate giant cell) is a mass formed by the union of several distinct cells (usually histiocytes), often forming a granuloma.
Langhans giant cells are
giant cells found in granulomatous conditions
They are formed by the fusion of epithelioid cells (macrophages), and contain nuclei arranged in a horseshoe-shaped pattern in the cell periphery.
a cytomegalovirus is
a genus of viruses in the order Herpesvirales
enlarged cells with enlarged nuclei present in the cells
Typical “owl eye” intranuclear inclusion indicating CMV infection
what are epithelioid macrophages
Epithelioid macrophage is an activated macrophage that resembles an epithelial cell with finely granular, pale eosinophilic cytoplasm and central, ovoid nucleus (oval or elongate). This cell type is able to merge into one another to form aggregates.
also called epithelioid cells
Metaplasia is
defined as abnormal change in the nature of a tissue.
is a potentially reversible change in which one adult cell type is replaced by another adult cell type of the same germ line. Specialized epithelium is replaced by less-specialized epithelium.
metaplasia of epithelium
morphologic finding that refers to the replacement of a group of one type of epithelial cells (e.g., glandular epithelial cells) to another type of epithelial cells (e.g., squamous epithelial cells).
dyskeratosis
is abnormal keratinization occurring prematurely within individual cells or groups of cells below the stratum granulosum
types of regeneration
physiological
reparative
- restitution (restitutio ad integrum)
- incomplete regeneration (substitutio)
pathological
- hyporegenerative
- hyperregenerative (extra flesh – caro luxurians)
Organisation in pathology is
replacement of dead tissues and other foreign masses with reactively developing connective tissue.
e.g. Encapsulation (calcifications)
Wound heals by first intention (per primam intentionem) or by second intention (per secundam intentionem).
define Wound healing by first intention and latin translation
per primam intentionem
Healing by first (primary) intention, or primary closure, refers to the healing of a wound in which the edges are closely re-approximated.
In this type of wound healing, union or restoration of continuity occurs directly with minimal granulation tissue and scar formation.
define wound healing by second intention and give latin translation
per secundam intentionem
Secondary intention healing means a wound will be left open (rather than being stitched together) and left to heal by itself, filling in and closing up naturally.
