Unit 1 Flashcards
physiology
study of the normal functions of cells, tissues
and organs in the human body in order to maintain homeostasis
(function is an aspect of structure)
homeostasis
the maitenance of a constant internal enviroment
Rudolf Virchow
all disease is result of disorders in cellular function
pathophysiology
study of the humans body’s response to injury to regain homeostasis and/or the study of the body’s response when homeostasis cannot be achieved
cellular adaptations explained
cell has the ability to react in different fashions according to the type, strength and duration of altered stimulation it is receiving
injury
stimulus that alters or disrupts normal homeostasis or homeostatic mechanisms
atrophy
decrease in the size of cells due to less than normal amount of stimulation from any or all of the following
- decreased workload
- decreased blood supply
- decreased availability of nutrients
- decrease of hormonal influence
disuse atrophy
skeletal muscle cells and bone mass following immobilization of a joint
physiological atrophy
thyroglossal duct (small duct leading from the thyroid to tongue) atrophies in the baby
hypertophy
increase in the size of cells without an increase in cell number due to increased protein synthesis (skeletal/cardiac muscle) or decreased protein degradation
also increased hormonal stimulation
hyperplasia
increase in the number of cells due to mitotic division
2 types of hyperplasia
physiological and pathological
physiological hyperplasia
compensatory
- regeneration of tissue (kidney)
hormonal
- breasts during pregnancy
pathological hyprtplasia
endometrium in response to estrogen
- prostate gland in aging males
metaplasia
refers to the reversible replacement of one cell (tissue) type for another
metaplasia of epithelia always leads to
replacement with a less specialized and more rugged type o epithelium
examples of squamous metaplasia
- respiratory epithelium due to chronic smoke irritation
- cervix
dysplasia (atypical hyperplasia)
a change which usually precedes the onset of cancer
characterized by loss of normal uniformity of individual cells
tendency of disorganization of tissue as a whole
may display irregular hyperplasia and metaplasia
hypoplasia
an organ with a reduced number of cells
example
- turners syndrome
hypoplastic uterus and hypoplastic metacarpals
aplasia
a reduction in the number of cells to zero
- aplastic anemia
agenesis
total failure of an organ (or part of an organ) to develop
examples
- anencephaly (failure of forebrain development)
- sacral agenesis (failure of caudal region of spinal cord to develop)
neoplasia
new growth
tumor
characteristics of neoplasm (benign or malignant)
- abnormal, excessive growth
- lacks a useful function
- autonomous (tumor growth is uncontrolled and uncoordinated and their local environment and persists to grow in the absence of treatment
- self- perpetuating
- parasitic
benign tumor behaviors
- expansive
- remain localized
- encapsulated
- compress adjacent structures
- slow growth
- closely resemble parent tissue
- normal cell reproduction
