PNP WK6 Flashcards
What are chromosomes?
- made up of thousands of genes (segments of DNA that contain info about how to synthesise a protein)
- Body contains 23 pairs chromosomes, 22 pairs are autosomes and one pair is sex chromosomes
What is the difference between autosomal and X-linked inheritance?
Autosome: gene being expressed is located on an autosome
X linked: gene being expressed is located on the x chromosome
What is ploidy?
Number of sets of chromosomes in an organism, aneuploidy is abnormal no. of sets
What is a codon?
A sequence of 3 DNA/RNA nucleotides that correspond to a specific amino acid during protein synthesis
What is a point mutation?
replacement of a single base pair with another that can change the identity of an amino acid, create a stop codon, or create a new start codon
What changes can come from a point mutation?
- Turn off a gene so there is no protein
- Stop transcription early and producing a dysfunctional protein
- Prolong transcription so protein cannot function
- Increase function of a protein
- Create interfering protein with normal protein
What are chromosomal disorders?
- Error during meiosis where chromosomes swap portions
- Can cause a translocation (abnormal placement part of chromosome)
- Can cause an altered structure (deletion)
What are multifactorial disorders?
- Polygenic or teratogen exposure
- Caused by environmental factors
- Breast cancer or schizophrenia
What is somatic v gamete gene therapy?
Somatic: normal gene is inserted into somatic cells, cannot be passed on
Gamete: gene is passed on to the children of the person with a hereditary disease as a result of manipulation of the sex
What is organogenesis?
when differentiation and development of the organs are taking place
What is a teratogen?
a chemical, physical, or biological agent that produces abnormalities during embryonic or fetal development.
What are the different routes of action for teratogens?
- Direct exposure to agent
- Through pregnancy exposure (takes a while)
- As a result of mutagenic effects of a teratogenic agent that occurs before pregnancy
Describe the development of the heart for an embryo
- First to form and develop
- Begins pumping blood on day 21/22
- Develops from cardiogenic area
- Made from cardiogenic cords that form single hollow tube
- Internal septa forms day 28
- AV and semilunar valves develop wk 5-9
Describe the development of the respiratory system for an embryo
- Begins 4 wks into gestation
- Endothermal tissue will form laryngotracheal bud, and trachea will develop proximally
- Alveolar ducts with type I cells, surfectant is produced
- Completed by 36 wks
Describe the development of the renal system for an embryo
- Pronephros, non functional stage
- Mesonephros, transitional kidney formed
- metanephros, development continues until wk 10
- Nephrogenesis, development of ureteric buds, which develop into the ureter, pelvises, calyces, and collecting ducts until wks 32-36
Describe the development of the GI system for an embryo
- Foregut develops: The pharynx, oesophagus, stomach, liver, gall bladder, pancreas and part of the duodenum
- Midgut develops: duodenum, jejunum, ileum, ascending colon, and two-thirds of the transverse colon
- Hindgut develops: one-third of the transverse colon, the descending colon, the rectum, and the urogenital sinus.
What is cellular senescence?
- state of irreversible growth arrest, meaning that cells lose their ability to divide
- triggered by DNA damage (chemicals, mutation errors, reactive oxygen species
(-oxides) - triggered by telomere shortening
How does aging affect neuromuscular and cardiac function?
Neuro: loss of neurons and neural dendrite atrophy, declined motor strength and reflexes
Cardiac: Increased stiffness in blood vessels, decreased HR and diastolic ventricular relaxation
How does aging affect immune and integumentary function?
Immune: altered. diminished T helper cell function
Integ: thin dry skin, decreased sebum production, thick nails
How does aging affect respiratory and GI function?
Resp: decreased VO2max and elasticity in lungs
GI: Mucosal atrophy, constipation, dry mouth
How does aging affect renal and genitourinary function?
Renal: Glomeruli function decreased, decline in renal blood flow
Genit: Decreased bladder capacity, decreased testosterone in men and increased dryness in women
How is absorption of drugs affected by age?
- in the newborn infant; low levels of bile may lead to impaired absorption and reduced bioavailability of drugs
- In the adult, penicillin is poorly absorbed from the gut because it is degraded by stomach acid
- Slowed peristalsis and gastric emptying can lead to higher plasma drug levels than expected.
How is the distribution of drugs affected by age?
- concentration of plasma proteins is lower in the very young and the very old, leading to a higher proportion of unbound drugs in blood
- Drug activity and potential toxicity is increased, even though total drug concentration in the plasma is within the expected range.
- neonates, there will be a lower concentration of drug around its specific receptors and a diminished response
- in older people there will be a higher-than-expected drug concentration with greater effects due to ECF present
How is the metabolism of drugs affected by age?
- Neonates have a greater capacity to metabolise certain medications due to hepatic abilities
- In children the liver is much larger, therefore able to metabolise quicker
- In adults ability to metabolise deteriorates
