OCR Biology F214 Communication, Homeostasis and Energy Wed 25 Jan 2012

Reply 1180

good luck guys!

can someone explain to me control of heart rate?

we never got taught it (darn cover teacher!)

Reply 1182

VQG

11

Original post by undertaker1

precision and accuracy people???

THIS, sorry just didn't want this to go unnoticed at the bottom of the page!

Reply 1183

StrawberryKoi

12

Is anyone else hysterically flipping through their textbook and hyperventilating? Anyone?

:getmecoat:

Reply 1184

Leeshur

13

Original post by StrawberryKoi

Is anyone else hysterically flipping through their textbook and hyperventilating? Anyone?

:getmecoat:

I was shaking a little bit over excretion but there's no point. When I see some of the responses in this thread, I start doubting whether I know this stuff and it makes me panic.
You'll be fine, don't panic. We're all in this together. <3

Can anyone please explain the role of the Na-K pump in selective reabsorption?

Reply 1185

The Illuminati

4

PERITONEAL DIALYSIS can someone explain this please

Reply 1186

cashmoneyorg

7

Original post by Chris P Chicken.

No that would be synoptic knowledge..I have no idea why people are getting obsessive about it. :s-smilie:

I've got a question for all the people who don't revise the book cover to cover and forget to revise points at the very bottom of the book:

1.

A) What are the two components of the Adrenal gland?
B) Which of these components making glucocorticoids?

No cheating. :tongue:

a) adrenal cortex & medulla
B ) adrenal cortex

Reply 1187

Chris P Chicken.

Original post by StrawberryKoi

Is anyone else hysterically flipping through their textbook and hyperventilating? Anyone?

:getmecoat:

This ^

Reply 1188

TattyBoJangles

19

Original post by StrawberryKoi

Is anyone else hysterically flipping through their textbook and hyperventilating? Anyone?

Yup

Well, I go from being worried about Mechanics (tomorrow afternoon) to thinking, "Oh, I'll read some Biology to take my mind off it.."
I then panic about Bio.

I've come to a good compromise. Browse this thread whilst watching Biggest Loser :yep:

Reply 1189

undertaker1

OP

11

Original post by The Illuminati

PERITONEAL DIALYSIS can someone explain this please

http://www.youtube.com/watch?v=i6bctm7I3l4&feature=related

Reply 1190

undertaker1

OP

11

precision and accuracy people???

Reply 1191

im so fresh

12

lool just done the specimen paper.
With super unbelievable harsh marking and got 39/60 D:
i was looking through what i got wrong and yes i agree with a couple of earlier posts in this thread.
State the obvious!!!
i lost around 10 marks for not doing so.

Reply 1192

StrawberryKoi

12

Original post by The Illuminati

PERITONEAL DIALYSIS can someone explain this please

You again!

-surgeon inserts permanent tube into abdomen
-dialysis fluid inserted in tube, and flows into the body cavity (between abdominal wall and organs)
-the body's own peritoneum membrane acts as the dialysis membrane (and it's partially permeable)
-dialysis fluid contains correct concentration of substances (salts, proteins etc) that are found in a healthy person's blood
-substances are exchanged over the membrane between the blood and the fluid
-after a couple of hours the used dialysis fluid is drained out of the body

(edited 12 years ago)

Reply 1193

Leeshur

13

Original post by The Illuminati

PERITONEAL DIALYSIS can someone explain this please

The filter = the body's own abdominal membrane (peritoneum). A permanent tube is implanted into the abdomen. Dialysis solution is poured through the tube and fills the space between the abdominal wall and organs. Basically does the same thing as renal dialysis but is internal + the patient can be be mobile/doesn't have to stay in hospital.
The used solution is then drained from the abdomen after a couple of hours.

Reply 1194

VQG

11

Original post by Leeshur

I was shaking a little bit over excretion but there's no point. When I see some of the responses in this thread, I start doubting whether I know this stuff and it makes me panic.
You'll be fine, don't panic. We're all in this together. <3

Can anyone please explain the role of the Na-K pump in selective reabsorption?

Sodium pottasium pumps on the membranes of the cells linings the proximal convoluted tubule (opposite side to the membrane which is in contact with the proximal convoluted tubule) pump Sodium ions out of the cell into the tissue fluid. Creates an electrochemical gradient of sodium ions in the cells compared to the proximal convoluted tubule- so sodium ions move down their concentration gradient by faciliated diffusion in association with glucose through co transporter proteins into the cells.

Reply 1195

StrawberryKoi

12

Original post by Leeshur

I was shaking a little bit over excretion but there's no point. When I see some of the responses in this thread, I start doubting whether I know this stuff and it makes me panic.
You'll be fine, don't panic. We're all in this together. <3

Can anyone please explain the role of the Na-K pump in selective reabsorption?

That is so sweet of you, thanks for the reassurance. I guess we all are kind of nervous haha. Good luck for tomorrow morning! I'm sure you'll do great too.

I was nervous about excretion too but I feel a bit better now that I've gone over it :redface:

Reply 1196

cashmoneyorg

7

Original post by im so fresh

what is noradrenaline?
ive never heard of it.

its a neuro transmitter. released by accelerator nerve to increase heart rate part of sympathetic system

Reply 1197

undertaker1

OP

11

could someone go over the photosynthesis experiements please please please please

Reply 1198

The Illuminati

4

Original post by StrawberryKoi

You again!

-surgeon inserts permanent tube into abdomen
-dialysis fluid inserted in tube, and flows into the body cavity (between abdominal wall and organs)
-the body's own peritoneum membrane acts as the dialysis membrane (and it's partially permeable)
-dialysis fluid contains correct concentration of substances (salts, proteins etc) that are found in a healthy person's blood
-substances are exchanged over the membrane between the blood and the fluid
-after a couple of hours the used dialysis fluid is drained out of the body

I think I'm in love with you now :love:

Thank you so much

Reply 1199

Bi0logical

7

Original post by DeelyBopper

can someone explain to me control of heart rate?

we never got taught it (darn cover teacher!)

Hope these notes help :biggrin:

The various factors that affect the heart rate must interact in a coordinated way to ensure that the heart beats at the most appropriate rate.

Under resting conditions the heart rate is controlled by SAN. This has a set frequency, varing from person to person. However, the frequency of these excitation waves can be controlled by the cardiovascular centre in the medulla oblangata.

There are many factors that affect the heart rate.
- Movement of the limb is detected by stretch receptors in the muscles. These send impulses to the cardiovascular centre informating that extra oxygen may soon be needed. This tends to increase heart rate.

- When we excersise the muscles produce more carbon dioxide. Some of this reacts with water in the blood plasma and reduces its pH. The change in pH is detected by chemoreceptors in the carotid artieries, the aorta and the brain. The chemoreceptors send impulses to the cardiovascular centre, which increase the heart rate.

- When we stop exercising the concentraiton co2 in the blood falls. This reduces the activity of the accelerator pathway.Therefore the heart rate declines.
- Adrenaline is secreted in response to stressh,shock, pain. The presence of adrenaline in the blood increases heart rate. This helps prepare the body for activity.

- Blood pressure is monitored by stretch receptors in thew alls of the carotid sinus. This is a small swelling in the carotid artery. If blood pressure is too high, e.g. during exercise, the stretch receptors send signals to the cardiovascular centre. this responds by reducing the heart rate.

There are two nerves which connect the medulla oblangata and the heart. This is the accelerator nerve and the vagus nerve. The accelerator nerve increases the heart rate, and the vagus nerve decreases heart rate. So e.g. if you're excercising then the impulse travels from accelerator nerve to increase heart rate. (pump more blood around body/oxgenated / remove co2, etc)

OCR Biology F214 Communication, Homeostasis and Energy Wed 25 Jan 2012

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