In the coordination of a heart beat, does the impulse get to the AVN then is delayed or delayed before it gets to the AVN?
Thanks!

Posted from TSR Mobile

Reply 1786

HelloNell

Can someone please explain co-transport with glucose and sodium? thanks :smile:

Reply 1787

gapyearstudent96

Things to note when asked to state relationships/ interpret graphs?

Reply 1788

buckeybarnes

4

Original post by biojames

What happens in systole ? I understand diastole and the stages now but not sure about that bit ?

if diastole is relaxation it follow that systole must be contraction, there are two parts:-

atrial systole= the walls of the atria contract to the move the last bits of blood into the ventricles

ventricular systole= after a delay so the ventricles can fill, the walls contract which forces shut the av valves which increases pressure as the contract, meaning pressure is higher than aorta or pulmonary artery pressure so sl valves forced open and blood moves out of the ventricles into the aorta and pulmonary artery
walls much thicker than atria so can provide more pressure with contraction
:smile:

gl

Reply 1789

jameslondon05

2

Original post by LearningGeek

Can someone please tell me how to do the cardiac output, the first answer is 85.7
i know the formula to work it out, bit cant to it from the table

Posted from TSR Mobile

i got
(148-55)*0.7 = 65.1

(edited 8 years ago)

Reply 1790

Questioner1234

7

In what detail do we need to know active transport?? Do we need to understand ADP and ATP in detail?

Reply 1791

nicklongy

2

Original post by biojames

What happens in systole ? I understand diastole and the stages now but not sure about that bit ?

diastole is essentially relaxation, where as systole is contraction. We have both ventricular and atrial systole, which relates to these chambers of the heart contracting. Atrial systole which is controlled by the firing of the SAN node will force blood from the artia into the ventricles. Ventricular systole, which happens after atrial systole and a pause (through the use of non-conducting fibres and the AVN node) contracts as the purkinje fibres are fired (from the bottom up).
Hope this helps.

Reply 1792

frances98

19

Can someone please explain systole and diastole?

Reply 1793

HelloNell

Original post by Malicious

Whats the difference between the smooth and rough ER structure ? I know what they both do but i always label it wrong.

RER has ribosomes on it but SER doesn't

Reply 1794

Monkey D. Luffy

7

Original post by Malicious

Whats the difference between the smooth and rough ER structure ? I know what they both do but i always label it wrong.

RER has ribosomes and SER does not

Reply 1795

RespectedDon

1

Is there a trend in past papers in terms of the similarity of questions that come up or else? I have done 9 past papers once-- so as a repeat is it better to do the recent one like june 2013 and may 2012 or the old one like may 2010 jan 2010? What is the hardest past paper you have been through/?

Reply 1796

Boundless_x

16

Original post by Malicious

Whats the difference between the smooth and rough ER structure ? I know what they both do but i always label it wrong.

RER has small dots (ribosomes) on it in the pictures when labelling :smile:

Reply 1797

buckeybarnes

4

Original post by Malicious

Whats the difference between the smooth and rough ER structure ? I know what they both do but i always label it wrong.

they are the same apart from the fact that the rough endoplasmic reticulum is studded with ribosomes for a large surface area for the synthesis of proteins and producing glycoproteins and a pathway for the transport of proteins

Reply 1798

frances98

19

Original post by RespectedDon

Is there a trend in past papers in terms of the similarity of questions that come up or else? I have done 9 past papers once-- so as a repeat is it better to do the recent one like june 2013 and may 2012 or the old one like may 2010 jan 2010? What is the hardest past paper you have been through/?