OCR Biology F211 resit - 16th May

same! was so pissed off that nothing came up on the heart.

you should try the june 2009 paper. it has a good mix of both but mainly heart/cells stuff :smile:

Thanks!

will do

a) Describe the cardiac cycle, reference to the action of the valves in the heart.

b) Describe how heart action is coordinated with reference to the sinoatrial node, the atrioventricular node and the purkyne tissue.

anyone?

Reply 21

aedai

Someone please post about the diastole stage. I'm so confused about it.
When does it happen..

Reply 22

abi.tanner

diastole is when the muscles in the heart relax after having to withstand the high pressure in ventricular systole when the blood is pumped out of the heart to the whole body and the lungs, getting ready for the atrial systole.
when the cardiac muscles relax, the artria fill with blood increasing the pressure which leads to the atrial systole.
i'm pretty sure this is what happens. i did this without the text book infront of me so it's pretty much off the top of my head and very basic.
i hope it's actually right....

(edited 12 years ago)

Reply 23

si7hy

just like to say that reading this has given me so much confidence in how im going to perform.

if some people cant get how to calculate magnification thennn... lawl

Reply 24

aedai

Original post by abi.tanner

diastole is when the muscles in the heart relax after having to withstand the high pressure in ventricular systole when the blood is pumped out of the heart to the whole body and the lungs, getting ready for the atrial systole.
when the cardiac muscles relax, the artria fill with blood increasing the pressure which leads to the atrial systole.
i'm pretty sure this is what happens. i did this without the text book infront of me so it's pretty much off the top of my head and very basic.
i hope it's actually right....

Does it go like this then. Atrial systole, atrial diastole, ventricular systole, ventricular diastole.

The atria's relax, which allows blood to flow in.. then the atrioventricular valves open due to pressure in the atrium and then the atriums contracts to allow blood to flow into the ventricles while they are relaxed. Ventricles contract and due to the pressure in the Ventricles, the semi lunar valves open and blood flows through the aorta/pulmonary arteries.

Have I even got that right? I'm seriously panicing as I did a whole poster on this before my first exam in Jan and I can't understand it when I read through and I used so many diagrams =/

Today I need to drill tissue fluid and lymph into my head somehow.. and go over bohr shift again and then recap over the notes I've done.
Beginning of this week I was really confident but now that I know heart is going to pop up..I don't think I'll do too well :frown:

anyway thanks for the post abi :smile:

Reply 25

anonymous_angel_16

10

Original post by rawr13

Hey, anyone got any specific predictions on what might be on the exam? since the jan one was mainly on plant stuff. ?

I think, based on January exam, spirometer is going to come up.
Heart (especially cardiac cycle since it has never came up), translocation, tissue fluid
these topics have a high chance of coming up but I obviously don't know for sure.

Reply 26

yamamotootsu

Revising for Biology in 1 day :biggrin:

Reply 27

rawr13

Original post by yamamotootsu

Thanks!

will do

a) Describe the cardiac cycle, reference to the action of the valves in the heart.

b) Describe how heart action is coordinated with reference to the sinoatrial node, the atrioventricular node and the purkyne tissue.

anyone?

B) Basically the SAN initiates a wave of excitation which spreads across and down the atria. then it reaches the base of the atria where it meets a disc of tissue which cant conduct electricity. at the top of the inter-ventricular septum is the AVN node which is the only route through for the wave of excitation. <-- thats what basically causes the slight pause between the atria contracting and the ventricles contracting.

anyway the wave of excitation carries away from the AVN down the purkyne tissue to the base of the septum. wave of excitation spreads around walls of ventricles. The excitation spreads up from the apex (base) of the ventricles and therefore the muscles contract.

i think thats right anyway.

Reply 28

yamamotootsu

Original post by anonymous_angel_16

I think, based on January exam, spirometer is going to come up.
Heart (especially cardiac cycle since it has never came up), translocation, tissue fluid
these topics have a high chance of coming up but I obviously don't know for sure.

a spirometer consists of a chamber filled with oxygen floating on a tank of water. A person breaths from a mouthpiece attached to a tube connected to the oxygen tank. Breathing in takes oxygen from the chamber so it sinks down, and breathing out pushes air back into the chamber which floats up. The movements of the chamber is recorded using a datalogger. :biggrin:

Reply 29

aedai

Original post by yamamotootsu

a spirometer consists of a chamber filled with oxygen floating on a tank of water. A person breaths from a mouthpiece attached to a tube connected to the oxygen tank. Breathing in takes oxygen from the chamber so it sinks down, and breathing out pushes air back into the chamber which floats up. The movements of the chamber is recorded using a datalogger. :biggrin:

also remember the soda lime used which absorbs carbon dioxide.
Also a nose piece is used to prevent any air from escaping and keeping the results more valid.

Before using the spirometer you need to make sure the participant is healthy. You need to make sure that the mouth piece has been disinfected and ensure there are no leaks.

Theres lots of questions on the spirometer in the Jan 2010 exam :smile:

Reply 30

rawr13

past papers : http://pastpapers.org/as-papers/transport-biology-papers

Reply 31

yamamotootsu

Revising the cardiac cycle right now :biggrin:

Sequence of Contraction

1) Filling phase
2)Atrial Contraction
3) Ventricular Contraction

1) When both the atria and the ventricles are relaxed, blood flows into the heart from the major veins. The Blood flows into the atria, then through the open atrioventricular valves and into the ventricles. This phase is called Diastole

2) The atria contract simultaneously, pushing blood into the ventricles(atrial systole). Blood fills the atrioventricular valve, causing them to snap shut and preventing the blood from flowing back into the ventricles.

3) when the pressure in the ventricles is higher than the pressure in the arteries, the semilunar valves are pushed open and blood is pushed out of the heart. the ventricles relax. cycle repeats.

Reply 32

bulletproof_love

Original post by yamamotootsu

Revising the cardiac cycle right now :biggrin:

Sequence of Contraction

1) Filling phase
2)Atrial Contraction
3) Ventricular Contraction

1) When both the atria and the ventricles are relaxed, blood flows into the heart from the major veins. The Blood flows into the atria, then through the open atrioventricular valves and into the ventricles. This phase is called Diastole

2) The atria contract simultaneously, pushing blood into the ventricles(atrial systole). Blood fills the atrioventricular valve, causing them to snap shut and preventing the blood from flowing back into the ventricles.

3) when the pressure in the ventricles is higher than the pressure in the arteries, the semilunar valves are pushed open and blood is pushed out of the heart. the ventricles relax. cycle repeats.

Is this all we need to know about the cardiac cycle?

Reply 33

Madmaz

1

Original post by rawr13

use AIM to work out magnification.

Magnification = image size/actual size

be careful with converting your units. i.e into nanometres.

I always get my conversions wrong so I get the whole question wrong! How do you do yours??

Thank you!!!

Reply 34

Madmaz

1

Original post by aedai

also remember the soda lime used which absorbs carbon dioxide.
Also a nose piece is used to prevent any air from escaping and keeping the results more valid.

Before using the spirometer you need to make sure the participant is healthy. You need to make sure that the mouth piece has been disinfected and ensure there are no leaks.

Theres lots of questions on the spirometer in the Jan 2010 exam :smile: