Adaptations & Injury Flashcards
(19 cards)
Describe the characteristics of disease through correct nomenclature
- Etiology: The cause of disease
- Pathogenesis: The mechanism causing disease
- Pathology: Molecular and morphologic changes to cells or tissues
- clinical manifestations: signs & symptoms (symptoms can be only told by patients/what they experience)
- Complications: The Secondary, systemic, or remote consequences of disease
- Prognosis: The anticipated course of disease
- Epidemiology: Incidence, prevalence and distribution
Recall the types of injury-inducing stimulus
- Hypoxia
- Chemical agents
- infectious agents
- immunologic reactions
- Genetic defects
- Nutritional imbalance
- Physical agents
- Aging
Describe the two broad categories of adaptations
- Physiological adaptation – cellular response to normal stimulation (increased demand/hormonal influences mainly)
o Hormones
o Endogenous chemicals
-Pathological adaptation – cellular response to stimulation secondary to underlying disease/to avoid injury by modulation of structure and function (injurious agents - ischemia & toxins)
List the 4 major types of adaptations
- Hypertrophy: Increase in cell size, increase in organ size
- Hyperplasia: increase in cell number, increase in organ size
- Atrophy: decrease in cell size/number, decrease in organ size
- Metaplasia: change in cell type
o Note: it’s an adaption if the effect is reversible when the stimulus is removed
Describe Hypertrophy and give examples (pathologic and physiological)
- Caused by mechanical force/stretch; e.g. muscle contraction, or hormonal/growth factor stimulation
- Increased workload (physiological and pathological stimuli)
- Increased size of cells resulting in increased size of organ
- No new cells, just larger cells
- Non-dividing cells increase in size (myocytes, skeletal muscle)
o Physiologic example: body builder increased workload bigger muscle cells ripped physiques
o Pathologic: hypertension increased workload enlarged heart improved performance degeneration
Describe hyperplasia and give examples
- Increase in organ size by an increase in cell number rather than increase in cell size
- Only in cell populations capable of dividing
- Physiological and pathological response
o Physiologic example: hormonal (puberty), compensatory (liver resection)
o Pathologic example: hormonal (endometriosis), chronic stress (callous)
Describe atrophy and give examples
- Caused by a reduction in work demand, or stimulation by hormones or growth factors
- Reduced size of organ resulting from decrease in cell size and number
- Physiological atrophy: common during normal development (embryonic structures, uterus following pregnancy)
- Pathologic atrophy: depends on underlying cause
1. (Decreased amount of structural proteins and organelles due to decreased protein synthesis and increased protein degradation) - Decreased workload
- Loss of innervation
- Loss of blood supply
- Inadequate nutrition
- Loss of endocrine stimulation
- Pressure
- A decrease in size makes the cell more oxygen & energy-efficient
- E.g. if you broke your arm and put it in a cast, you are not moving your hand, and so the muscles in your forearm aren’t being used anymore, when you take the cast off, the muscles in your forearm would’ve become smaller
Describe metaplasia and give examples
- Change in cell type due to chronic irritation or inflammation
- Replacement of one differentiated cell type with another
- Cells sensitive to stress replaced by a cell type better able to withsand stress
- Stem cell reprogramming
E.g. Cigarette smoking
- Ciliated columnar cells to stratified squamous cells
E.g. Chronic gastric reflux
- Stratified squamous cells to Gastric columnar epithelial cells
Define homeostasis
- Homeostasis: The body’s ability to maintain a stable internal environment, and disruptions to homeostasis can lead to disease
- (Alternative definition): A state of balance among all the body systems needed for the body to survive and function correctly.
Describe the three types of cell types
Cells in body are categorised into three ways in how their constant activity is situated:
1. Labile cells:
- Constantly replicating and copying themselves/going through mitosis
2. Quinn essence cells:
- Almost asleep; aren’t copying/replicating themselves but can if need be
3. Permanent cells:
- Cells that will never go through mitosis again, can’t ever replicate/copy, can’t go through mitosis to repair themselves
- E.g. muscle cells or neuronal cells
Describe the cell injury type - Hypoxia
> Oxygen deficiency
Interferes with aerobic oxidative respiration
Caused by:
- Pneumonia=inadequate oxygenation
- Haemorrhage=blood loss anaemia
- Carbon monoxide poisoning/iron deficiency
- Reduced oxygen-carrying capacity
- Ischemia=loss of blood supply to tissue
Describe the cell injury type - chemical agents
- Poisons: “all substances are poisons, the right dose separates a poison from a remedy”
- Tobacco
- Alcohol
- Therapeutic & non-therapeutic drugs
- Glucose & salt alter osmotic balance
- Oxygen
- Environmental agents (pollution, lead, mercury)
Describe the cell injury type - infectious agents
- Conventional infectious agents:
- Bacteria
- Virus (20-300nm)
- Fungi (2-200micrometres)
- Parasites - Unconventional infectious agents:
- Prions
- Small proteinaceous infectious particles which are resistant to inactivation by most procedures that modify nucleic acids…and underscores the requirement of a protein for infection
Describe the cell injury type - immunologic reactions
- Immune imbalance
- Autoimmunity – immune response attacks self instead of external microorganisms
- Hypersensitivities – allergy – overreacts to harmless environmental antigens
- Graft rejection – artificial form of injury to cell; recognises an organ transplant as foreign
- Immune deficiency – naturally acquired (genetic mutation)
Describe the cell injury type - Genetic defects
- Congenital malformations (down syndrome), single base mutations causing functional deficiency or protein misfolding
Describe the cell injury type - Nutritional imbalance
- Deficiency
- Malnutrition
- Vitamins (A, D) - Excess
- Obesity
- Type 2 diabetes
- Hypertension
- Hyperglyceridemia
Describe the cell injury type - Physical agents
- Mechanical trauma (abrasions, contusions lacerations)
- Thermal injury (burns, hyperthermia, hypothermia)
- Electrical injury
- Ionising radiation
- Atmosphere (pressure)
Describe the cell injury type - Aging
> Progressive decline in cellular function and viability
- Genetic factors
- Exogenous influences
Describe the fundamental cellular adaption diagram
Yes
