Exam 1: Cellular injury, stress, & genetics Flashcards
Atrophy
Cellular adaptation in which cells revert to the smaller size. It
is the shrinking of skeletal muscle seen in paralysis or even
inactivity from bed rest.
Acts to decrease energy requirements
Conditions it occurs:
1. disuse
2. denervation
3. loss of endocrine stimulation
4. inadequate nutrition
5. ischemia or decreased blood flow
Hypertrophy
An increase in the individual cell size and often mass where there is an enlargement of functioning tissue. It increases the cell’s functional components which leads to greater metabolic demand and energy needs
Physiologic hypertrophy
Enlarged muscle that is adequately perfused and supplied with
blood flow. There is proportional increase in cell size and
enhancement of coronary blood supply. (Working out and muscles larger)
Pathological hypertrophy
An increase in cellular size without an increase in the supportive structures necessary for the enlarged cells increase in metabolic demand. Seen in hypertension or heart failure. LV hypertrophy
Hyperplasia
Increase in the number of cells in the tissue or gland, generally stimulated by hormonal or compensatory cellular mechanism.
normal: increase in breast gland cells when a
woman is pregnant
maladaptive: a keloid
Metaplasia
Replacement of one cell type by another cell type generally due to environmental conditions
chronic inflammation
(Gastroesophageal reflux is a good example of this and can lead to cancer)
Dysplasia
Chronic inflammation or precancerous condition dysplastic cells vary in size, shape and architectural organization compared to healthy cells. (Cervical dysplasia example)
Classic precursor to cancer.
Neoplasia
Uncoordinated, uncontrolled proliferative cell growth that is cancerous like a tumor
Ischemia
Inadequate blood flow
Hypoxia
Oxygen deprivation, blood cannot deliver oxygen to cells this
can be body or region
-emia: low ox content in blood
-ia: low ox supply in body
↓oxygen →anaerobic metabolism →use up glycogen stores →↑lactic acid →alter cell member → failure Na+/K+ pump → ↓intracellular K+ →↑Na+ and H20→cell swells→ ↓mitochondrial function
Infarction
Also known as ischemic necrosis, it is the death of tissue due to prolonged ischemia
oxidative stress
Cell injury induced by free radicals
Causes changes in gene and protein expression
Reactive oxygen species exceeds the ability of the body to neutralize and eliminate
plays role in development of cancer and other disease processes
free radicals
Have a single unpaired electron in an outer orbit that creates instability and reactivity with adjacent molecules they react with constituents of the cell’s plasma causing oxidative degradation
generated from: excessive UV light, radiation, chemicals/drugs, reperfusion
antioxidants
block free radicals and prevent or delay cell damage
vitamins A, C, E, and zinc
Apoptosis
Genetically programmed degenerative change that causes cell death no adverse effects on the body a reduction in cell size, intact plasma membrane but an altered structure, no adjacent inflammation
Necrosis
Cellular death due to stressors of insults that overwhelm the cell’s ability to survive, it is irreversible an enlarged cell size, disrupted plasma membrane, cellular contents leak out of cell and frequent adjacent inflammation
Gangrene
Occurs when a considerable mass of tissue undergoes necrosis
Seyle’s stress response theory
Explains the body’s response to acute, intermittent stressors. Stressors can be positive or negative. The adaptive ability is the way in which individuals manage the stress and reduce the stressor’s effect on their life.
Homeostasis is the equilibrium between various physiologic parameters, adaptive ability depends on coping mechanisms, reaction to a stress is individual
3 stages:
1. alarm - fight or flight response
2. resistance - recovering from illness
3. exhaustion - chronic exposure increases risk for disease
McEwen’s Stress response theory
Stress is a routine part of daily life not episodic or a crisis
Frequent stressors change the body’s physiologic balance and create new set points, allostasis load accumulates because of four mechanisms:
repeated stressful experiences
inability of the individual to adapt to stress
prolonged reaction to a stressor
inadequate response to a stressor
Allostasis
The dynamic state of balance that changes to exposure to stressors
Allostatic load
The wear and tear on the body systems caused by stress reactions
Gene
Specific group of nucleotides of the DNA helix that carry a code for protein
Segment of DNA on chromosome
gene locus refers to location of a gene on a chromosome
Karyotype
Picture of the chromosomes that are contained within the DNA of a species, human karyotype as 23 pairs of chromosomes
Mendelian genetics
Inherited traits are passed from parents to offspring. The Punnett square is a predictable pattern in transmission of a single gene, not used for multifactorial inheritance. Used with autosomal dominant, autosomal recessive, and sex linked.
Somatic cells
46 chromosomes formed through mitosis
Gametes
23 chromosomes and called haploid cells formed through meiosis
Homozygous vs Heterozygous
homo- Both alleles on each corresponding chromosome are the same
hetero- The alleles on corresponding chromosomes are not the same
aa vs Aa
Teratogens
Agents that may or may not cause mutations but can damage a developing fetus
Phenotype
How the genetic traits manifest in the individual the actual, physical, or somatic expression of the genotype
Genotype
The genetic makeup of a person
Genetic info stored in the sequence of base pairs
Penetrance
ratio of how many persons have the phenotype as compared to those that have the genotype
likeliness of getting the trait
ex:
75 have clinical features
100 have mutation
75/100= .75 75% penetrance
Expressivity
A disorder can be expressed by symptom severity, variation of a phenotype
variability of the level of the trait
Multifactorial diseases
Involvement of many genes and environment aspect
aneuploidy
Abnormal number of chromosomes, a cell that does not contain 23 pairs of chromosomes
Can be sex-linked (abnormal # of sex chromosomes)
Trisomy
Three copies of one chromosome or gain of a chromosome
Downs
Monosomy
Missing one chromosome from a pair. All autosomal monosomies are not compatible with life. Monosomy of the X chromosome is compatible with life.
Carrier
A person, who is heterozygous for a recessive trait and
does not manifest it, has a recessive allele, but the
dominant allele silences it. Example Dd.
Disruption of intracellular calcium homeostasis
causes cell injury
Normal A & P: ICF Ca+ low compared to ECF & maintained through calcium/magnesium exchange system
Patho: Ischemia and toxins lead to an increase in ICF Ca+ which leads to further cell membrane damage and ATP depletion
Body’s responses to stress
Adrenal medulla/hypothalamus - releases norepinephrine and epinephrine
Posterior pituitary - releases antidiuretic hormone (ADH)
Anterior pituitary - releases adrenocorticotropic hormone (ACTH)
Adrenal Cortex - releases cortisol and aldosterone
Transcription
Messenger RNA (mRNA) is formed from DNA; takes place in nucleus
Translation
Synthesis of a protein using the mRNA template in cytoplasm
-Supported by rRNA and tRNA
