Pre-Clinical Physiology Questions

[Dr.Adnan]

QUESTION: 1
The black widow spider (Latrodectus spp.) is a spider notorious for its neurotoxic venom. When this spider injects its venom into a victim, a continous contraction of muscles will occur therefore it causes the diaghram to contract and there will be no expiration and breathing will be inhibited thus leading to immediate death. The machanism that this spider uses is connected in disrupting the action potential by:-

  A-Blocking the receptors of the acetylcholine.
  B-inhibiting the release of acetylcholine.
  C-causing an explosive release of acetylcholine.
  D-Destroying body choline reserviors.

[Abdullahi!]

Please Dr. Adnan do you mind clarifying whether this is a best answer MCQ or true or false.

It seems to me that this spider (Black widow spider) causes the massive release of acetylcholine from synaptosomes and in addition, inhibites high-affinity choline uptake.

This could be mean that both A and C are correct although if it is a best answer i would choose C.

[Dr.Adnan]

as far as I know option C is the only correct one, so you get it right. 
but for the other notion i will check for it.

Sry for the delay i was busy

[Amal]

No i think the best answer is A,  acts by blocking transmission of nerve impulses to the muscles thats how the poison is powerful. what makes you choose C?. Dr Adnan correct me if am wrong.

[Dr.Adnan]

Amal thank you for your comment
First, for the first choice(blocking the receptors of acetylcholine) is caused by substance called Curare, which is found in some types of mushrooms , practicaly , the red indians used it on their spear heads while they were fighting to give their enemy a lethal shot.
Curare is a reversible inhibitor of acetylcholine receptors.

for option B (inhibiting the release of acetylcholine.) it is caused by Clostridium botulinum which is found in some canned vegtables.

so as far as I know C is correct choice for the action of the venom of black widow spider.

and option D is obvious that it is wrong. because it talks about using ACH until it ends.

[Amal]

Dr Adnan, ohh thanks I now see why answer c is the correct answer.

[Dr.Adnan]

thank you amal
but I will do further research on this matter. my source was the guyton medical physiology book.

[Doc:aar]

Question 2:-
Which of the flowing tissue produce surfactant:-
     
     a)-type 1 alveolar epithelial cells
     b)-type 4 alveolar epithelial cells
     c)-type 5 alveolar epithelial cells
     d)-type 2 alveolar epithelial cells

[Munim]

A.C Doc:aar.
I think (D) is Correct Answer
( type 2 alveolar epithelial cells produce surfactant).

[Doc:aar]

www mumin
    thank you mumin.... the correct answer is (D)

[Doc:aar]

Question 3:-
in ECG , which of the following represents when atrial and ventricular are relaxed
 
    A)-PR interval
    B)-TP segment
    C)-ST segment
    D)-PR segment
    E)-QT interval

[Abdullahi!]

The ECG shows atrial systole. This is called a P-wave. Then ventricular systole happens. This is called the QRS or QRS-complex. It is called a complex because there are three different waves in it. The Q-wave, R-wave, and S-wave. Then the ECG shows ventricular diastole. This is called the T-wave. Atrial diastole happens then too. But it is not seen separate from ventricular diastole, so it's TP segment (B).

[Doc:aar]

 thank you abdullahi .. (B) is the correct answer ..so  you get it right

[Abdullahi!]

Question 4:-
A baby is born to a parents with blood group [B(-)], the baby's blood group may be:

a) A (+)
b) A (-)
c) AB
d) O (+)
e) O (-)

[Dr.Adnan]

I am definatly not sure of this answer but I think it is option E.
Because the child have 1/4 probability to get O blood group other 3/4 being B blood group. That is if both parent are B negative.