BIOL312: Pathophysiology - Exam 3 Questions With
Complete Solutions
A 29-year-old new mother, who delivered her infant three days
ago, is admitted to the hospital with chest pain and is diagnosed
as having venous thrombosis with pulmonary emboli.
What factors would contribute to this woman's risk of
developing these thrombo-emboli? Correct Answer -
Pregnancy (increased estrogen = increased CF's, decreased
blood flow and increased backflow = increased venous stasis)
- Bedrest / immobilization pre- or post-birth
- Trauma / surgery (increased venous stasis, varicosities if valve
damage)
All babies born in the US are tested for sickle cell trait and
disease. Why could they still develop it in adulthood if they test
negative? Correct Answer After 1 year, most of our Hb should
be adult, not fetal. Mutations can occur in the adult beta chains
**Malaria parasite uses normal RBC, so a new shape protects
the RBC from being invaded again
**Sickle cell trait/disease is most common in African Americans
and Hispanics because of malaria's origins
Atrial fibrillation, "A-fib", is a type of cardiac arrythmia. The
resulting disorganized electrical signals cause the atria to bear
rapidly and chaotically, so blood doesn't flow properly. How
does A-Fib put someone at risk of creating a blood clot in the
atria? If they "throw" the clot (clot travels out of the atria),
,where is it likely to lodge? Correct Answer Blood stasis in atria
= increased clot risk
Left atrium structure has more pockets for blood to sit in = more
likely to clot
Lodge in brain
**Can't go to lungs because aorta goes out to body and clots
can't go through capillary beds to go to right side of heart then
lungs
Describe the 2 pathways that must be activated for effective
hemostasis are activated. Correct Answer Intrinsic pathway:
Activated by CLOTTING FACTOR
**Activates when CF comes in contact with collagen inside
blood vessel
Extrinsic pathway: Activated by TISSUE FACTOR
**Released from OUTside blood vessel
Describe the clotting cascade process. Correct Answer Intrinsic
+ extrinsic pathways activated
Inactive Factor X converts to active Factor Xa
Converts Prothrombin into thrombin
Thrombin acts like an enzyme and converts fibrinogen into
fibrin, making a clot
Describe the cycle of an RBC's life span. Correct Answer
Small intestine absorbs amino acids, iron, folic acid (Vit. B), and
Vitamin B12 from our diet (what we eat)
,Erythropoiesis in red bone marrow
Erythrocytes circulate for 90 - 120 days
Expired erythrocytes break up in liver and spleen
-> Cell fragments phagocytized
-> Hemoglobin degraded to heme and globin
-> Globin: protein hydrolyzed to free amino acids
-> Heme: split into iron (some stored, some reused, some lost),
and biliverdin in liver (to bilirubin, to bile, to feces)
Describe the epidemiology of infectious mononucleosis.
Correct Answer Most EBV cases are subclinical (no
signs/symptoms)
50% of population seroconverts (antibodies present in serum
against EBV) < 5 years old
12% adolescents (teens)/young adults (HS + college)
seroconvert each year - 50% develop mono
Describe the iron cycle. Correct Answer 1. Dietary iron eaten,
enters stomach
2. Iron absorbed in intestines
3. Iron binds to transferrin in blood, transported
4a. Some iron stored in liver (as ferritin)
4b. Some iron goes to heart and muscles (for myoglobin)
4c. Some iron goes to bone marrow (for RBC synthesis)
5. Circulates for 90-120 days before entering spleen for
breakdown
, Describe the loop of CO2 to O2 in an RBC and a respiring tissue
(internal respiration). Correct Answer CO2 comes from
respiring tissue through respiratory membrane
Some CO2 dissolves into the blood plasma, some bind with a
plasma protein, but most find a hemoglobin on an RBC
a. CO2 binds with hemoglobin, making HbCO2
b. CO2 binds with water, enzyme turns them into carbonic acid
c. Carbonic acid breaks into bicarbonate ion and H+
-> Bicarb gets pumped out of the cell via exchanger, Cl- comes
in (chloride shift)
d. H+ tell hemoglobin to release its oxygen to the tissue
Oxygen released from hemoglobin into tissue
**Carbonic acid reaction happens in plasma too
Describe the loop of O2 to CO2 in an RBC and an alveoli
(external respiration). Correct Answer O2 comes from alveoli
through respiratory membrane
Some O2 dissolves into the blood plasma, but most find a
hemoglobin on an RBC
a. O2 binds with hemoglobin, making H+
b. H+ binds with bicarbonate to make carbonic acid
c. Carbonic acid splits into CO2 and water back into alveoli
Hydrogen ions tell hemoglobin to release its CO2 to the alveoli
CO2 released from hemoglobin into alveoli
Describe the pathophysiology of infectious mononucleosis.
Correct Answer Virus penetrates salivary & pharyngeal
epithelial cells, infecting the B cells in these areas
-> Infected B cells circulate in the lymph/liver/spleen and
activate cytotoxic T cells (CD8)
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