Exam 1 Flashcards
What is Genetic Imprinting?
When certain genes are differentially “turned off” during either paternal or maternal gametogenesis
What chromosome is involved in both Prader-Willi and Angelman syndrome?
Chromosome 15
What syndrome results from the deletion of Chromosome 15 when it occurs in the mother?
Angelman Syndrome
What syndrome results from the deletion of Chromosome 15 when it occurs in the father?
Prader-Willi Syndrome
What environmental factors are thought to contribute to chromosomal breakage?
Drugs (Alcohol, Cocaine, Valprorate, lack of Vitamin A)
Infection (Rubella, Toxoplasma, Varicella)
Radiation Damage (radioactive Iodine)
Maternal Factors (Diabetes, Phenylketonuria)
What is deletion?
the loss of a piece of a chromosome
What is Isochromosome Formation?
When there is incorrect chromosomal division which leads to the fusion of the long and short arms of the chromosome, leading to the duplication of a single arm, and a loss of the other
What is Ring Formation?
The telomere of the chromosome breaks because after replication for cell division, this portion becomes shorter and shorter, aging the chromosome’s stability until it becomes lost - then fusion occurs between the short and long arm portions which creates the ring structure.
What is Translocation?
when 2 chromosomes break simultaneously with one another and these broken pieces swap locations
What is Centric/Robertsonian Translocation?
When 2 non-homologous chromosomes break and the long arms of the chromosomes fuse into one single chromosome
What is aneuploidy?
An abnormal number of chromosomes
What are the two reasons why numeric disorders of the sex chromosomes is “better tolerated” than those involving the autosomes?
Involves the inactivation of all but one X chromosome
The Y chromosomes contains very few genes
What is Turner Syndrome?
Absence of all or part of a female’s two X chromosomes
Most are spontaneously aborted
Short individuals, with diagnosis mostly occurring during teen years because of poor development
Contain underdeveloped ovaries and has no secondary sex characteristics (infertile)
What is Klinefelter Syndrome?
1 or more extra X chromosome
Tall, abnormal body proportions (wide hips, narrow shoulders, long arms/legs)
Lack of facial, body, and pubic hair
Normal Intellect
Cells will have a Barr body
Infertile
What is a Barr body?
Inactive X chromosomes in the female somatic cells
A nurse noticed that the newborn baby had low set ears, low set nasal bridge, producing tongue, and wide epicanthal folds (skin folds around eye). What is this disorder and what may the nurse suspect?
Down Syndrome
These characteristics are most properly related to some sort of chromosomal defect
Although a majority of chromosomal abnormalities are sporadic, they can on occasion be directly inherited. The genetics basis for the baby’s aberration will be identified by:
Karyotyping
What is Nondisjunction?
failure of the 2 chromosomes to separate during meiosis
What are the approaches to disease?
By body system (cardiovascular, pulmonary, renal…)
By disease etiology (cause) (genetic, biological, chemical agents, physical forces)
By signs and symptoms (what do they look like or perceive?)
What is Etiology?
Causes of disease or physiological abnormalities
What is the etiology of Spina Bífida?
combination of genetic, nutritional, and environmental risk factors
E.g., family history of neural tube defects and folate (Vitamin B-9) deficiency
What is Pathophysiology?
What is the disease and how does it effect the body
What are Signs of disease?
Factors that are objective and measurable
What are Symptoms of disease?
Factors tat are subjective, and can be different for all individuals
E.g., pain, nausea
What is a Diagnosis?
Identification of disease (DX)
List some common medical acronyms
DX diagnosis
BP blood pressure
RR respiratory rate
T temperature
CBC complete blood count
S/S signs and symptoms
SOB shortness of breath
TX treatment
How many pairs of chromosomes are there?
23 pairs
Where are chromosomes located in the nucleus?
Around the outer edge of the nucleus
(Not bundled within the middle as once thought)
What is chromatin?
A complex of DNA and protein that eukaryotic genes are contained
What are his tones?
The protein of chromatin
Are octomers
What is Histone Methyltransferases?
When methyl groups are added to the lysine residues on H3 and H4 histones tails and repress transcription by condensing chromosome structure
What is Histone Demethylases?
When methyl groups are removed
What does Histone Acetylation do?
Neutralizes the basic charge of lysine and allows DNA to uncoil from histones to activate transcription and turn genes on
Acetyltransferases - acetyl groups are added
Deacetylases - acetyl group are removed
What is Deacetylation?
Removing acetyl residues from lysine which stabilizes the nucleosomes and represses transcription, turning genes off
How many genes are in the X and Y chromosomes?
X = 900-1400 genes
Y = max of 200
What is Dosage Compensation?
Equalization of genetic information in XX female genotype - one member of the XX pair is randomly inactivated in female cells
What is a common example of X chromosome inactivation?
Orange and black calico cats
Fur color on the X chromosome
What does DNA Methylation do?
blocks transcription factors from binding to enhancer sites; “turn off”
What are Exons and Introns?
Exons are regions of the DNA sequence that code for a protein
Introns are regions of DNA between exons that do not code for a protein
What are some diseases from faulty transcription?
Developmental disorders
Cancer (e.g., leukemia)
Diabetes
Alzheimer’s (misfolded proteins accumulate in nerves and brain, killing the nerves)
What are some signs of Prader-Willi?
Intellectually deficient
Constant hunger @ 2 years of age (leads to obesity and Type 2 diabetes) - hard to control blood sugar levels
Short stature
Small hands and feet
What are some signs of Angelman Syndrome?
Intellectual deficient
Poor control of muscle movement
Smile and laugh frequently
Happy and excitable personalities
Poor sleep
Lack of speech
What is the cause of Fragile X Syndrome and what are some symptoms?
Mutation FMR1 gene regulates neuronal synapse (nerve-nerve connections) - impacting every nerve in the extremities and brain
Intellectual impairment
Large face and ears
Hyperextendable joints
Mitral valve prolapse - which leads to damage to heart
What is Inversion?
2 breaks in a single chromosome
Can be pericentric (breaks on opposite sides of centromere) or paracentric (same side of centromere)
What is a Karyotype?
Allows visualization of chromosome structure - gives idea “where to look” for these genetic defects
What are Congenital Disorders?
Abnormal body structure, function, or metabolism present at birth
What are the 2 periods of vulnerability in fetal development?
Development of placenta
During fetal organ development
How does alcohol lead to Fetal Alcohol Syndrome?
alcohol is lipid soluble and passes freely across the placenta to the embryo fetus - the concentration is the same in the fetus as the mother
Leads to small head (microcephalic), neurological abnormalities, behavior dysfunction, and developmental delays
What are the three proliferative capacity of tissues?
Labile- continue to divide and replicate throughout life, replacing cells that are continually being destroyed (e.g., skins cells)
Stable - normally stop dividing when growth ceases (e.g., kidney, lung, liver cells)
Permanent - cannot undergo mitotic division (e.g., neurons, cardiac muscle cells)
What are Histones role in gene expression?
Modifications regulate what genes can be transcribed
Mutations may completely alter what is transcribed in a cell
How many proteins make up one histone?
4
What is the role of transcription factors?
These factors are proteins that are involved in the process of transcribing DNA into RNA
With methylation, these factors are unable to bind to DNA
What is the role of DNA Methylation in gene expression?
Blocks transcription factors from binding to enhancer sites - “turn off”
What is Multifactorial Inheritance?
No clear cut pattern of inheritance; multiple genes; environmental factors; cannot be predicted
Explain Toxoplasmosis
Can be acquired through raw/undercooked meat and cat feces which have this parasite.
This parasite is easily able to cross placenta and affect the fetus - heading to the brain
Leads to premature birth, eye damage, and fluid build up in the brain
What are the steps of wound healing?
- Inflammatory Phase: 0-24 hrs
Neutrophils are first recruited to help stop bleeding and prevent infection
Macrophages remove ell debris and produce growth factors for repair - Proliferative Phase:
Fibroblast rebuilds wounds, divides to build a network
Growth of new blood vessels (to replaced those lost) and collagen is used to structure the wound
3.Would Contraction and Remodeling: 3 wks - 6 months
Scar remodeling
Restoration of tissue architecture
Decreased blood vessels (removes extra that are unnecessary)
What may impair wound healing?
Age - cells are younger and more responsive in younger individuals
Nutrition/Malnutrition - deficiencies limit ability to repair (proteins, fats, carbs, Vit A, C, K, Zinc)
Impaired blood flow and oxygen delivery
Impaired inflammatory and immune responses
Infection
Wound Seperation
Foreign bodies
Overproduction of collagen
What do collagen and elastin do in the extra cellular matrix?
Act as fibrous structural proteins
Collagen - structure
Elastin - ability to stretch and relax
What is Atrophy?
Decrease in cell size
What is Hypertrophy?
Increase in cell size
What is Hyperplasia?
Increase in the number of cells through mitotic division
What is Metaplasia?
Replacement of adult cells
How do cells change to accommodate changes in the internal environment?
Size - atrophy (e.g. muscle not working), hypertrophy (e.g. cardiac cells, muscle cells getting bigger)
Number - cells are dividing more
Form - metaplasia (e.g. Barrett’s Esophagus)
Which cellular growth change best describes the cellular adaption seen in chronic cigarette smokers?
Metaplasia - cells begin to change and adapt to stuffing off from the cigarette smoke
What are the types of cellular injury?
Mechanical
Chemical
Radiation
What is a mechanical cell injury?
Impact with another object (e.g. car crash, falling off bike)
Extremes of temperature
Electrical forces
What is radiation cell injury (and the three types)?
Ionizing- quickest, focused and narrow (e.g. chemo)
UV - Not deep, skin and retina damage (e.g. sunburn)
Nonionizing - slow waves, infrared light (e.g. ultrasound)
What is the difference between Primary and Secondary Healing?
Primary - small, clean wound (e.g. paper cut)
Secondary - great tissue loss with contamination (e.g. scraped leg, stick impaled into leg)
