Several biology questions

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I was going to post these in the organismal biology Q&A thread, but the link gave me a 404 error. Anyway, here they are, and any speed would be appreciated IMMENSELY as my test date is this friday:

What should I know specifically about the Krebs cycle?

Regarding synaptic activity of neurons, what does "propagation between cells without resistance loss" mean?

In the endocrine system, what should I know about "specific chemical control at the cell, tissue, and organ level"?

What is the role of the spinal cord in reflexes?

What should I know about image processing?

What is the "Mechanism of stimulation by antigen"?

What should I know about vasoconstriction and vasodilation in surface capillaries?

How does the excretory system maintain homeostasis of blood pressure?

What do I need to know about cell communication and gene regulation in development?

I know it's a lot, but it's all straight from the MCAT syllabus, which is probably what contributes to the vagueness.

Eric

 

[viper420]

well i dont know all of them from the top of my head; but il try to answer whatever i can

1) as far as krebs cycle goes just know what goes into it (acetly-coa) and what is produced (6 NADH, 2FADH2 etc), as far as everything in between it will prob be given in the passage if it is asked

2) I dont know exactly what ur asking here, but if your refering to propagation of the action potential down the axon then it means that it dosent run out of energy and evenly flows down the axon, dont know if that makes sense.

3) dont know what ur asking, but as far as endocrine system goes, be able to distinguish b/t peptide(or protein) hormones, and steriods. in mechanism, transport, location of binding, stuff like that. And also know the major hormones of the endocrine system and what reponse they elicit.

4) Basically bypasses the upper brain regions, and allows simple reflexes to occur without central nervous system processing, classic example is the petela reflex (knee jerk)

5) This i dont know at the moment

6) When you say surface capillaries, do you mean those that lead to the skin? In general you should know that it is not actually the capillaries that are constricting or dilating (due to the fact that they have no smooth muscle) it is actually the arteries and arterioles that do this. Vasoconstriction of the arteries that lead to the skin occurs when the body is trying to conserve heat (cold weather) by diverting blood flow away from skin
Vasodilation occurs when the body is trying to remove excess heat

7) Basically there are many things that occur, There are speciall types of cells (i can recall what they are called) that are located near the prox con tubuels (sorry for spelling) in the nephron
They sense the blood pressure, when blood pressure is to low they cause the release of renin, which activates the renin-angiotensin pathway (might want to go over that) but ultimately blood pressure is increased due to aldosterone release, as well as increased total pheriperal resistance, and alot of other things happen (just cant think of them right now)

http://www.gcrweb.com/HeartDSS/charts/fig4.jpg

8) know induction, differentiation, and as far as gene regulation i am not sure

I hope that helps, and yea some other things you might want to go over are
- Which structures each germ layer gives rise to (ectoderm, mesoderm, endoderm) usually pops up on most test as a descrete and is an easy point

- know the menstrual cycle ( or at least the main points of it, such as LH surge causes ovulation)

if i think of anything else il let you know

 

[macmini]

5. Spinal cord is where many of our muscle/motor reflexes originate.

 

[AZFutureDoc]

Good luck getting all this down by Friday...