Exam #1 Flashcards
Nucleus
components: contains the nucleoulus
primary function:
1. cell division
2. control and protect genetic information
3. in charge of replication and repair of deoxyribonucleic acid (DNA
Nucleolus
a small, dense structure composed largely of RNA
located inside the nucleus
Ribosomes
Component: RNA-protein complexes (nucleoproteins)
Characteristics:
- synthesized in the nucleoulus
- secreted into the cytoplasm through pores in the nuclear envelope called nuclear pore complexes (NPCs)
Main function:
- to provide sites for cellular protein synthesis
mitochondria
components: organelles
function:
responsible for cellular respiration and energy production
Keys:
- Think Adenosine triphosphate (ATP= energy)
ATP functions as the energy-transferring molecule
Mitochondria
dietary proteins, fats, and starches (ex.carbohydrates) are hydrolyzed in the intestinal tract into amino acids fatty acids, and glucose
they are then absorbed, circulated, and incorporated into the cell, where they may be used for vial cellular processes, including ATP production
Lysosomes
maintain cellular health:
1. effficient removal of toxic cellular components
2. removal of useless organelles
3. signals cellular adaptation
components:
- signaling hubs of a sphisiticated network for cellular adaptation and maintenance of metabolic homeostasis.
- the signaling functions have far-reaching implications for metabolic regulation in health and in disease
Golgi complex (Golgi apparatus) mail carrier and traffic
Components:
- a network of flattened, smooth membranes and vesicles frequently located near the nucleus of the cell
- proteins from the endoplasmic reticulum are processed and packaged into small membrane-bound sacs or vesicles called secretory vesicles.
Main functions:
- “refining plant”
- directs traffic (ex. protein, polynuleotide, polysaccharide molecules) in the cell.
Adenosine Triphosphate (ATP)
Characteristcs:
- “fuel” inside living cells
- the energy-carrying molecule
Functions:
- drives biological reactions necessary for cells to function
- for cells to function, it must be able to extract and use the chemical energy in organic molecules
- stores and transfers energy from one molecule to another. Energy stored by carbohydrate, lipid, and protein is catabolized and transferred to ATP.
Atrophy
decrease in size of cell
ex of physiologic atrophy:
- thymus undergoes physiologic atrophy during childhood
- uterus decreases in size after childbirth
- tonsils shrink in adolescents
pathologic atrophy
- occurs as a result of decreases in workload, use, pressure, blood supply, nutrition, & hormonal stimulation
ex. bed bound patients exhibit disuse atrophy which is a type of skeletal muscle atrophy
Hypertrophy
increase in size of a cell
physiologic hypertrophy
ex: hypertrophy of myocardial cells (myocytes) such as endurance training
Physiologic atrophy
Example
- thymus undergoes physiologic atrophy during childhood
- uterus decreases in size after childbirth
- tonsils shrink in adolescents
Pathologic atrophy
- occurs as a result of decreases in workload, use, pressure, blood supply, nutrition, & hormonal stimulation
ex. bed-bound patients exhibit disuse atrophy which is a type of skeletal muscle atrophy increases in size of the cell
benefits
Pathologic hypertrophy
ex: secondary to hypertension (HTN)
- results from chronic hemodynamic overload, such as from HTN or heart valve dysfunction
- when left ventricular hypertrophy (LVH) occurs secondary to HTN, it represents pathohypertrophy
- prolonged cardiac hypertrophy progresses to contractile dysfunction, hemodynamics are altered, and finally heart failure,
Hyperplasia
increase in number of cells
- results from an increased rate of cellular division
- response to a stimulus (ex. injury)
- occus when the damage is severe or prolonged or when it results in cell death.
Requires cells to undergo mitosis- single cell divides into 2 identical cells
Main mechanism for hyperplasia
- production of hormones or growth factors> stimulate remaining cells after injury or cell loss to syntehsize new cell components > division
- increased output of new cells from tissue stem cells
mature cells have differing capacity for hyperplastic (miotic) growth)
Pathological: Benign prostatic hyperplasia (BPH)
Metaplasia
replacement of cells
- normal columnar ciliated epithelial cells of the bronchial lining have been replaced by stratified squamous epithelial cells
- can be reversed if irritant stopped
Cell injury: hypoxia
lack of sufficient oxygen within cells
- the single most common cause of cellular injury and is a prominent feature of pathological states encountered in bacterial infections, inflammation wounds cardiovascular defects, and cancer.
- can result from several circumstances
- reduced oxygen content in the ambient air, loss of hemoglobin
decreased RBC production - respiratory and Cardiovasc. diseases
Common cause:
- ischemia: reduced supply of blood= low oxygen/decreased perfusion
Impacts:
- normal physiological processes: differentiation, angiogenesis, proliferation erythropoiesis, overall cell viability
Mitochondria are the primary consumers of oxygen
Cell injury: ethanol
alcohol use disorder
- liver enzymes metabolize ethanol to toxic acetaldehyde
acetaldehyde is a highly toxic substance and known carcinogen
Chronic alcohol consumption
- chronic alcohol consumption breaks down the gut barrier function= leaky gut > impaired gut motility= delayed gastric emptying time
- induces chemical gastritis and impaired absorption of nutrients ( folic acid, thiamine, vitamin B6, magnesium, and phosphorus)
Folic acid deficiency= problematic in people consuming large quantities of alcohol
- serious when consumed during pregnancy > fetal alcohol syndrome
Magnesium- second most abundant micronutrient in the body
- magnesium deficiency in almost all people with ^ alcohol consumption and/or liver disease.
- urinary excretion of magnesium is increased secondary to alcohol consumption, and total body stores of magnesium become depleted.
Ethanol alters through urinary and fecal excretion.
Radiation
ionzing radiationis emitted by x-rays, y-rays, and alpha & beta particles = emitted from atomic nuclei in the process of radioactive decay
Main pathologic mechanism
- damage to DNA= BAD
- generates free radicals
Free radicals
electrically uncharged atom or group of atoms having an unpaired electron
- having one unpaired electron makes the molecule unstable
- to stabilize, it gives up an electron to another molecule or steals one
capable of injurious chemical bond formation with proteins such as fragmentation and folding, lipids, carbohydrates= key molecules in membranes and nucleic acids
= cause DNA damage and mutations
Antioxidants contribute to protections against damage caused by free radicals
function
- initiation and progression of diseases
Apoptosis and necrosis
Two main types of cell death
Apoptosis
~ 10 bill. new cells are created and destroyed
- usually physiological role
- a programmed cell death that is regulated or programmed
- usually a normal physiological process of the elimination of unwanted cells
Necrosis
usually pathologic (culmination of irreversible cell injury)
Characterized by:
- rapid loss of plasms membrane
- organelle swelling
- mitochondrial dysfunction
Hypoxia is the #1 major cause of cellular injury leading to necrosis
Ex. necrosis: cell death during a myocardial infarction
Aging and the cell/tissues
Every physiological processes can be shown to function less efficiently
Effects of aging depends on how we care for ourselves and genetics
- senescence (loss of cell’s power of division and growth) causes loss of tissue-repair capacity
- increase in stem cell exhaustion
- peripheral vascular resistance increases
Delayed emptying of stomach
decreased immune response to T-dependent antigens
-increased accumulation of proinflammatory tissue
Vulnerable populations to fluid balance
Infants:
- 75%-80% TBW
- They have a high metabolic rate
- Their kidneys are not mature enough to counter fluid losses.
Older adults:
- thirst sensation is diminished
Hydrostatic pressure
- At the arterial end of capillaries, fluid moves from the intramuscular space into the interstitial space b/c capillary hydrostatic pressure (BP) is higher than the capillary on optic pressure
- facilitates the outward movement of water from the capillary to the interstitial space and is mainly influenced by blood pressure.
Oncotic pressure
Is heavily influenced by plasma proteins (albumin)
- Low plasma albumin causes edema, especially in the lower extremities, as a result of a reduction in plasma oncotic pressure.
Renin angiotensin-aldosterone system (RAAS)
When circulating blood volume or BP is reduced, renin, an enzyme secreted by the juxtaglomerular cells of the kidney, is released in response to sympathetic nerve stimulation and decreased perfusion of the renal vasculature.
Aldosterone (think sodium)
Hormonal regulation of sodium and potassium balance is influenced by aldosterone.
- When circulating blood volume or blood pressure is reduced: Aldosterone causes Na+ and H2O resorption (hangs onto Na+ and H2O), and thus increases BP and blood volume.
- However, sacrifices K+ by increasing excretion thus hypokalemia.
Hyperaldosteronism
Causes: Hyperkalemia, hyponatremia, and fluid volume deficit
Hypoaldosteronism
Causes: Hyperkalemia, hyponatremia, and fluid volume deficit
Antidiuretic hormone (ADH) - think water
Secretion of ADH and the perception of thirst are stimulated by a decrease in plasma volume, increase in serum sodium, decreased BP (so decreased perfusion)
Natriuretic peptides
Hormones that include atrial natriuretic peptide (ANP) produced by the myocardial atria, brain natriuretic peptide (BNP) produced by the myocardial ventricles, and urodilatin within the kidney.
- Natriuretic peptides decrease BP and increase NA+ and H2O excretion
- Counteracts the RAAS- it is an Antagonist of the RAAS
Sodium (Na+)
Regulator of fluids, nerve impulse conduction, acid-base balance, cellular chemical reactions, and transport of substances across the cellular membrane
Hyponatremia
Associated w/ hypoaldosteronism
- loss of sodium, inadequate intake, and some medications
- Sodium depletion usually causes hypoosmolality with an associated movement of water into cells (cellular swelling with potential for rupture) and cellular function is altered.
-Clinical manifestation are related to altered action potential in neuron and muscles so impaired nerve conduction and neurological changes
- N/V with less severe hyponatremia
-More severe: lethargy, seizures, coma = major cause of morbidity and mortality in ICU and older patients
Hyoernatremia
CNS is most serious, and some are the same as hyponatremia such as coma and seizures
Potassium (K+)
the major determinant of the resting membrane potential necessary for transmission of nerve impulses
Ratio of K+ in the ICF to K+ in the ECF
Major determinants of the resting membrane potential, which is necessary for the transmission and conduction of nerve impulses, maintenance of normal cardiac rhythms, and skeletal and smooth muscle contraction
Clinical manifestations of K+ imbalances
Think heart/cardiac functioning
- also a HUGE contributor to acid-base balance
Ex. An increase in hydrogen ions (acidosis) in the blood causes the body to shift hydrogen ions into the cell in exchange for potassium
Hyperkalemia
Oliguiric kidney failure (little to no urine output)
Addison’s disease (decreased production of aldosterone thus body holds onto K+)
Hyperkalemia should be investigated when…
- Hyperkalemia should be investigated when there is a history of renal disease, massive trauma, insulin deficiency, Addison disease, use of potassium salt substitutes, or metabolic acidosis
Hyperkalemia SHIFT
In states of acidosis, hydrogen ions shift into the cells in exchange for ICF potassium
Hypokalemia
- Decrease intake: starvation or anorexia nervous, inadequate replacement
- Inadequate replacement
- Increased renal loss: renal tubular failure, K+ losing diuretics, hyperaldosteronism, vomiting, diarrhea
Hypokalemia SHIFT
From ECF to ICFL respiratory/metabolic alkalosis
- insulin promotes cellular uptake of K+
Ex. When administering insulin in diabetic ketoacidosis (DKA), watch for decreased ECF potassium!!
Calcium (Calming)
Necessary ion for many fundamental metabolic processes
- it is the major cation associated with the structure of bones and teeth.
- It serves as an enzymatic cofactor for blood clotting and is required for hormone secretion and the function of cell receptors
- Plasma membrane stability, permeability, and repair are directly related to calcium ions, as is the transmission of nerve impulses and the contraction of muscles.
Hypokalemia Causes
- Inadequate intestinal absorption
- massive blood administration
- decreases in PTH and vitamin D levels;
- nutritional deficiencies
- elevated calcitonin levels
- pancreatitis
Hypocalcemia Manifestations
- increased neuromuscular excitability, tetany
- tingling, muscle spasms (particularly in hands, feet, and facial muscles)
- intestinal cramping, hyperactive bowel sounds
- osteoporosis and fractures
- severe cases show convulsions and tetany
- prolonged QT interval, cardiac arrest
Hyperkalemia causes
Hyperparathyroidisms
- bone metastases with calcium resorption from breast, prostate, renal, and cervical cancer
- excess vitamin D
- Many tumors that produce PTH
- calcium-containing antacids
Hypercalcemia manifestations
Many nonspecific;
- fatigue, weakness, lethargy, nausea
- anorexia, constipation
- impaired renal function, kidney stones
- heart: dysrhythmias, bradycardia, cardiac arrest
- bone pain
Calcium and phosphorous balance
Influenced by parathyroid hormone (PTH), calcitonin, and vitamin D
Phosphate
Think “energy” ATP (adenosine tri phosphate) and oxygen transport 2,3 DPG (2,3 diphosphoglycerate)
Hyperpophosphatemia causes
- Intestinal malabsorption related to vitamin D deficiency
- long-term alcohol use disorder
- increased renal excretion of phosphate associated with hyperparathyroidism
Hypophosphatemia manifestations
- Conditions r/t reduced capacity for oxygen transport by RBC and disturbed energy metabolism
- Leukocyte and platelet dysfunction; deranged nerve and muscle function
- severe cases: irritability , confusion, numbness, coma, convulsions
- possible respiratory failure- b/c of muscle weakness
-cardiomyopathies, bone resorption (leading to rickets or osteomalacia) same as hypercalcemia
Hyperphosphatemia causes
- Acute or chronic renal failure with significant loss of glomerular filtration (kidneys main excretory organ for phosphate)
- long-term use of laxatives or enemas containing phosphates
- hypoparathyroidism
Hyperphosphatemia manifestations
- Symptoms primarily t/t low serum calcium levels (caused by high phosphate levels)
- similar to symptoms of hypocalcemia
- when prolonged, calcification of soft tissues in lungs, kidneys, joints (same as hypocalcemia)
Magnesium (Calming)
is a cofactor in intracellular enzymatic reactions, protein synthesis, and neuromuscular excitability.
- Improves myocardial metabolism, reduces peripheral vascular resistance, and inhibits platelet function.
Hypomagnesemia Causes
Malnutrition, malabsorption syndromes, alcohol use disorder, urinary losses (renal tubular dysfunction, loop diuretics)
Hypomagnesemia manifestations
- Behavioral changes, irritability,
- increased reflexes, muscle cramps, ataxia, nystagmus, tetany, convulsions,
- tachycardia
Hypermagnesemia causes
- Usually, renal insufficiency or kidney failure with little or NO urine output!!
- (Mg+ excreted by kidneys and intestines);
- also, excessive intake of magnesium-containing antacids
Hypermagnesemia manifestations
- Lethargy, drowsiness; nausea and vomiting
- loss of deep tendon reflexes, muscle weakness
- bradycardia, heart block, cardiac arrest
- respiratory distress;
Acid- Base Imbalance
An acid-base imbalance is not a disorder in and of itself, it is a diagnostic sign.
- In order to correct the imbalance, treatment is targeted at resolving the cause of the imbalance
The body will compensate at all costs to maintain a range of
7.35-7.45
Perfect pH is
7.40
– less than 7.40 is considered acidosis;
- greater than 7.40 is alkalosis when evaluating pH during an exacerbation of a disease entity.
Respiratory Acidosis
Examples below of poor ventilatory status (hypoventilation) that cause retention of carbon dioxide (CO2) thus unable to eliminate a powerful acid via the lungs!!
✓ Respiratory failure – hypoventilation UGH!
✓ Chronic respiratory disease (e.g., COPD)
✓ Barbiturate or sedative overdose
✓ Respiratory muscle weakness
Respiratory Acidosis Pathophysiology
- CO2 retention from hypoventilation
- Compensatory response (lungs in trouble, kidneys try to help) is ↑ HCO3− retention by kidney, but this is not an immediate compensatory mechanism and does take some time to be effective. However, with chronic respiratory conditions such as chronic obstructive pulmonary disease (COPD), kidneys are very effective.
- Kidneys secrete hydrogen ions (H+).
- Bicarbonate is regenerated by the kidneys.
Respiratory Alkalosis
Examples below of increased elimination of carbon dioxide (CO2) - loss of too much acid from the body through the lungs (hyperventilation).
- Hyperventilation – causes: hypoxia, anxiety, fear, pain, fever
- Stimulated respiratory center (e.g., septicemia, stroke, meningitis, encephalitis, brain injury)
Respiratory Alkalosis Pathophysiology
Compensatory response (lungs in trouble, kidneys try to help) is ↑ HCO3− excretion by kidney
Metabolic acidosis
Increased ACID load= elevated anion gap
Increased hydrogen ion (H+) load Good way to remember: KILU
Metabolic Acidosis Increased Acid load= Elevated Anion Gap
KILU
K= Ketoacidosis (diabetes myelitis)
I= Ingestions (ethylene, glycol, salicaylates)
L= Lactic acidosis (shock)
U= Uremia
Metabolic Acidosis
Bicarbonate Loss (Normal Anion Gap) Causes
Diarrhea
Renal failure
Metabolic Acidosis Pathophysiology
- Gain of fixed acid, inability to excrete acid or loss of base
- Compensatory response (kidneys in trouble, lungs try to help) is ↑ CO2 excretion by lungs called Kussmaul respirations – the patient presents with increased rate and depth of respirations. Vomiting – trying to get rid of acid!
Metabolic Alkalosis Causes
Vomiting – loss of acid (pH of stomach contents = 2)
- Nasogastric suctioning
- Diuretic therapy
- Hypokalemia
- Any condition that elevates aldosterone or mineralocorticoids (which enhance sodium [Na] reabsorption and potassium [K] and hydrogen ion [H +] excretion) can elevate HCO 3 −.
Metabolic Alkalosis Pathophysiology
- Loss of strong acid or gain of base
- Compensatory response (kidneys in trouble, lungs try to help) is ↑ CO2 retention by lungs
General Overview: Genetics
Identification of a specific genetic lesion can lead to effective prevention and support early screening. Presence of a genetic component can alter the course of disease through prevention and lowering risk factors.
Also, a family history of a disease may mean that the person is more likely to develop the disease earlier in life: for example: a person with a first-degree relative with Alzheimer disease has double the risk.
Elements of Formal Genetics
- Alleles are different forms of genes located at the same locus on the chromosome.
- At any given locus in a somatic cell, an individual has two genes, one from each parent. An individual may be homozygous or heterozygous for a locus.
- An individual’s genotype is the person’s genetic makeup, and
- The phenotype reflects the interaction of genotype and environment.
Expressively
is the extent of variation in phenotype associated with a particular genotype. If the expressivity of a disease is variable, the penetrance may be complete but the severity of the disease can vary greatly.
Deoxyribonucleic acid (DNA)
Genes are functional regions of DNA.
-To serve as the basis of genetic inheritance, DNA must be able to provide a code for all the body’s proteins.
- DNA must be able to replicate itself accurately during cell division so that the genetic code can be preserved in subsequent cell generations.
- A mutation is any inherited alteration of genetic material.
DNA replication: polymerase - protein
- unwinds the double helix, one holds the strands apart, and others perform different distinct functions.
- The most important of these proteins
- This enzyme travels along the single DNA strand, adding the correct nucleotides to the free end of the new strand.
- Besides adding the new nucleotides, the DNA polymerase performs a proofreading procedure. -After the new nucleotide has been added to the chain, the DNA polymerase checks to make sure that its base is actually complementary to the template base.
- If it is not, the incorrect nucleotide is excised and replaced with a correct one. This procedure, one of the mechanisms of DNA repair, substantially enhances the accuracy of DNA replication.
Aneuploid cells, Monosomy & trisomy
those that do not contain a multiple of 23 chromosomes.
- Monosomy, the presence of only one copy of a given chromosome in a diploid cell, is the other common form of aneuploidy.
- Monosomy of any chromosome is lethal. However, newborns with trisomy of chromosomes 13, 18, or 21 can survive.
- This difference illustrates an important principle: loss of chromosome material has more serious consequences than duplication of chromosome material.
- An aneuploid cell containing three copies of one chromosome is said to be trisomy (a condition termed trisomy).
Example of aneuploidy
in an autosome is trisomy of the twenty-first Chromosome: Down syndrome was formerly called mongolism, but this an inappropriate term and no longer used.
- Individuals with this disease typically have intelligence quotients (IQs) between 25 and 70. The facial appearance is distinctive, with a low nasal bridge, protruding tongue, and flat, low-set ears.
Autosomal recessive
For a recessive allele to be expressed, they must exist in a homozygous form.
- The most common lethal autosomal recessive disease in white children is cystic fibrosis and is more common in females.
Example of autosomal recessive
- If a male has the gene for cystic fibrosis, an autosomal recessive disorder, and the female has no gene, the child may still be a carrier.
- Carriers do not usually show any phenotypic signs of the disease.
- Because most recessive alleles are maintained in normal carriers, they are able to survive in the population from one generation to the next.
Autosomal dominant
When one allele masks those of another they are in a heterozygote form.
- At a heterozygous locus, the dominant gene masks those of a recessive gene.
Autosomal dominant example
- Genes responsible for this form of breast cancer have been mapped to chromosomes 17 (BRCA1) and 13 (BRCA2).
- Women who inherit a mutation in BRCA1 or BRCA2 experience a 50% to 80% lifetime risk of developing breast cancer.
- Breast cancer aggregates strongly in families. If a woman has one affected first-degree relative, her risk of developing breast cancer doubles.
Autosomal dominant example
Alzheimer disease (AD).
- Later onset AD is rapidly increasing in the United States.
- AD before the age of 65 is usually associated with an autosomal dominant mode of transmission.
Sex chromosome aneuploidy
- Some conditions are caused by genes located on the sex chromosomes, and that mode of inheritance is referred to as sex-linked.
- The Y chromosome contains only a few dozen genes, so most sex-linked traits are located on the X chromosome and are said to be X-linked.
Sex chromosome aneuploidy - Female
- Females receive two X chromosomes, one from the father and one from the mother, so they can be homozygous for a disease allele at a given locus, homozygous for the normal allele at the locus, or heterozygous.
Sex chromosome aneuploidy- Males
- A male who inherits a recessive disease allele on the X chromosome will be affected by the disease because the Y chromosome does not carry a normal allele to counteract the effects of the disease-causing allele.
- Consequently, males are more frequently affected by X-linked recessive diseases, with the difference becoming more pronounced as the disease becomes rarer.
X inactivation sex chromosome aneuploidy
the presence of a single X chromosome and no homologous X or Y chromosome, resulting in a total of 45 chromosomes; and it causes a set of symptoms known as Turner syndrome.
X inactivation sex chromosome aneuploidy- Turner Syndrome
- Because they have no Y chromosome, persons with Turner syndrome are always female.
- They are usually sterile, however, and have gonadal streaks rather than ovaries.
Features of Turner Syndrome
-short stature, webbing of the neck in about half of cases, widely spaced nipples, coarctation (narrowing) of the aorta (in 15% to 20% of cases), edema of the feet in newborns, and sparse body hair.
- Their IQs are typically in the normal range, however intellectual abilities can be affected especially with impairment of spatial and mathematical reasoning ability.
- Teenagers with Turner syndrome are typically treated with estrogen to promote the development of secondary sexual characteristics.
Incidence rate & Example
- the number of new cases of a disease reported during a specific period (typically 1 year) divided by the number of individuals in the population.
- For example, during COVID, incidence rate was calculated on a weekly basis (number of new cases of COVID in one week)
Relative risk
a common measure of the effect of a specific risk factor.
- It is expressed as a ratio of the incidence rate of the disease among individuals exposed to a risk factor divided by the incidence of the disease among individuals not exposed to a risk factor.
Example:
The incidence of death from lung cancer is 1.66 in heavy smokers (more than 25 cigarettes daily), but only 0.07 nonsmokers.
- The ratio of these two incidence rates is 1.66/0.07, which yields a relative risk of 23.7 deaths.
- Thus, it is concluded that the relative risk of dying from lung cancer increased by about 24-fold in heavy smokers compared with nonsmokers.
Recurrence rate (RR) of multifactorial inheritance
1) If the expression of the disease is more severe RR is higher.
2) Recurrence risk becomes higher if more than one family member is affected. For example, the sibling recurrence risk for a ventricular septal defect (VSD, a type of congenital heart defect) is 3% if one sibling has been affected by a VSD but increases to approximately 10% if two siblings have been diagnosed with VSDs.
3) The recurrence risk for the disease usually decreases rapidly in more remotely related relatives.
4) Many genes and environmental factors contribute to multifactorial diseases.
Epigenetics Definition/Function
bridges DNA information and function by modifying gene expression without any alteration in DNA sequence.
- “Epi-“means on or above in Greek, and “epigenetic” describes factors beyond the genetic code.
- Epigenetic changes are modifications to DNA that regulate whether genes are turned on or off.
- These modifications are attached to DNA and do not change the sequence of DNA building blocks
Epigenetic modifications can cause
Epigenetic modification can cause individuals with the same DNA (IDENTICAL TWINS) to have different disease profiles –
For example the occurrence of asthma in only one of a pair of identical twins.
• As twins age, they demonstrate increasing differences in methylation patterns of their DNA sequences, causing increasing numbers of phenotypic differences.
Causes of Epigenetic modification
Environmental factors, such as diet and exposure to certain chemicals, may cause epigenetic modification.
Epigentic factors
• Epigenetic factors are behaviors and environmental factors that can change how genes work, turning them “on” or “off”. These factors can include:
• Exposure to toxins: Air pollution, diesel exhaust, cigarette smoke, plastics, BPA, heavy metals like lead or cadmium
• Substances: Alcohol, tobacco, recreational drugs, and certain prescription medications
• Lifestyle: Foods, physical activity, stress levels, relationships, social interactions, community support, and access to healthcare
• Epigenetic changes can occur throughout life, both as part of normal development and aging, and due to exposure to environmental factors. These changes can affect health in different ways.
