SCD and DSD Flashcards
Sickle cell hemoglobin and malaria
Malaria resistance due to the plasmodium parasite not being able to infect the host because sickle cells die easily.
Sickle cell and climate change
Due to oxygen levels dropping quickly, sickle cells crisis will occur very often and create a crisis sue to RBC sickling and blocking oxygen and blood flow.
As climate change, increased in temperature allows mosquitoes to breed at higher altitude.
Sickle cell shape and blood vessels
When RBC sickle, they now can’t go through blood vessels as well and therefore lead to blockage of blood flow which impairs oxygen delivery to the body,
Anemia
sickle cells lead to shortage of red blood cells
Fetal hemoglobin vs adult hemoglobin
alpha and gamma chains have a higher affinity for oxygen, suck oxygen out of the mother’s body
alpha and beta chains are found in adult hemoglobin
Sickle cell disease
Genetic condition that causes anemia while preventing malaria
Hydroxyurea
Increases the production of fetal hemoglobin which stops the polymerization of sickle cells, increase of gamma units
Treatments for SCD
Blood transfusions to increase red blood cells counts.
Bone narrow transplant which is the only permanent cure which is where red blood cells come from
Penicillin
Blocks out infection and treat them so helps when the spleen is dysfunctional due blockage of red blood cells causing brushing easily
Erythrocytes contain large amounts of hemoglobin which transport oxygen and carbon dioxide
4 subunits, globin proteins that have iron, they are very shallow centers that optimizes surface area to volume to facilitate gas exchange and move through narrow blood vessels.
RBC have a short life spam
Hypoxic environment
Oxygen deficiency due to change in high altitude, respiratory diseases, anemia, reduced blood flow and cyanide poisoning.
Plasma concentration
90% water
Proteins
Kwashiorkor
Nitrogenous waste
Electrolytes
Respiratory gases
Nutritents
What are the formed elements of blood
They include both cellular and acellular structures
Erythrocytes which are red blood cells begin in red bone narrow
Leukocytes which are white blood cells
Platelets
Sickle cells is a hematological condition
Functions of the blood?
Blood carry nutrients and oxygen to the body
Hematocrit
Counts of red blood cells in plasma which can detect dehydration ( less water, more cells) and anemia .
Anemia
Low iron level which leads to sickled cells blocking blood flow in small vessels
Tonicity affects the likelihood of sickling
Under hypertonic sodium solution, water will leave the cell and increases sickling leading to occlusion and adhesion which is under normoxic or hypoxic conditions.
Draw the inheritance pattern of SCD
Sickle cell disease
A mutation in hemoglobin beta subunit which results in an abnormal form of hemoglobin. Under hypoxic conditions, RBC sickles and crystalize with each other and that reduces the oxygen delivery to the body and make them prone to breaking apart easily.
Treatments
Blood transfusions to increase RBC counts and decreased sickle cells counts
Hydroxyurea- increase fetal hemoglobin
Gene therapy and gene editing
Bone narrow transplant- only curable treatment, replacing bone narrow where erythrocytes are made.
Symptoms of SCD and how this relates to the mutation
Pain crisis due to blood flow blockage from sickled cells because of the beta subunits being able to crystallize and stick to blood vessels
Anemia- Low count of red blood cells due to rapid breakage because of the sickled shape
Swelling of hands and feet
Spleen damage due blockage of blood flow and that can lead to infections very easily
Evolutionary advantage of SCD
SCT is advantageous in people living in malaria endemic area because they have higher resistance to malaria due to sickle cells dying before plasmodium can infect the host.
Heterozygous advantage.
What kind of mutation is SCD and how does it affect hemoglobin structure
A point mutation that is due from T to A change which changes the amino acid from glutamic acid to Valine, a non-conservative missense mutation.
The beta subunits will crystallize into fiber with one another and the capacity to carry oxygen and it’s easier to block blood flow in vessels.
SDS can be caused by..
Structural changes and chemical changes
Structural changes by non-disjunction
In meiosis 1, nondisjunction lead to 2 gametes with 3 chromosomes and 2 gametes with 1 chromosomes
In meiosis 2, nondisjunction lead to gametes with 3 chromosomes, 1 chromosomes and 2 gametes with 2 chromosomes.
Trisomy 21
Down syndrome lead to 3 extra copies of chromosome 21
Trisomy 13
Patau syndrome with extra digits, harelip, single eye which is 3 copies of chr 13
Life expectancy 130 days.
DSD due to both chemical and structural events
At first, sex is undetermined then female or male genitals appear
The adrenal cortex uses cholesterol to make androgens and genital structures develop due to the presence/absence of DHT.
Guevedoce, 5-AR enzyme, a chemical difference
causes pseudo hermaphroditism in males
5-AR enzyme can’t convert testosterone to DHT which then leads to female hormones production
Female pseudo hermaphroditism
21 alpha hydroxylase malfunction
Hypo cortisol lead to adrenal androgens because progesterone can’t be converteed to cortisol and the pathway to adrenal androgens occurs.
DSD by structural diff due to nondisjunction
X0 = turner syndrome, infertile woman with broad shoulders and spaced out nipples
AIS androgen incendivity syndrome
A male that has female morphology which is due to a receptor mutation, X linked recessive,.
