Clarification. (1 Viewer)

[Lordie]

So, just some concepts I've never really understood/got a definite answer for.

With T and B Lymphocytes. So phagocytes are the second line of defence, and target any antigen, correct? If this process doesn't work, T helper cells produce a chemical, which trigger a specific T and B cell being produced, cloned, then multiplied? T cells engulf antigens, where as B cells produce antibodies to target the antigen? So then, one group of the cloned cells act straight away, destroying the antigens present, where as the other group, are known as memory T or B memory cells, and act to ensure 'immunity' to these antigens into the future?

Is that all that is needed on T and B cells?

Then theories on xylem and phloem transport. I've heard so many different things for this. One talks of translocation for Phloem, and the transpiration stream for xylem. Are these the correct theories?

Thanks.

 

[danz90]

So, just some concepts I've never really understood/got a definite answer for.

With T and B Lymphocytes. So phagocytes are the second line of defence, and target any antigen, correct? If this process doesn't work, T helper cells produce a chemical, which trigger a specific T and B cell being produced, cloned, then multiplied? T cells engulf antigens, where as B cells produce antibodies to target the antigen? So then, one group of the cloned cells act straight away, destroying the antigens present, where as the other group, are known as memory T or B memory cells, and act to ensure 'immunity' to these antigens into the future?

Is that all that is needed on T and B cells?

Then theories on xylem and phloem transport. I've heard so many different things for this. One talks of translocation for Phloem, and the transpiration stream for xylem. Are these the correct theories?

Thanks.

hey

ur idea of immune response is essentially correct.

for xylem and phloem, transloction occurs in both of them from what i know. Just remember, in xylem its the transpirational stream, thats supported by the cohesion-adhesion-tension of water molecules and cellulose in the plant cells... and for phloem its the pressure flow (source-path-sink) theory, where substances actively move against (or is it along?) a pressure gradient.

 

[Lordie]

Right, thanks. So it is the right theory, heh.

So my T and B cell explanation...is it complete, or am I missing crucial elements? Heh. I'm looking through about 3 text books, and think I'm on the right track.

These two things are the only things I'm not too sure on. Thanks.

 

[danz90]

Right, thanks. So it is the right theory, heh.

So my T and B cell explanation...is it complete, or am I missing crucial elements? Heh. I'm looking through about 3 text books, and think I'm on the right track.

These two things are the only things I'm not too sure on. Thanks.

the only part u could maybe refine a little is...

When phagocytes engulf a pathogen, they display an antigen fragment on their MHC markers on their cell membrane surface. This is then detected by T-cells, stimulating them to release particular cytokines, which then stimulates B-Cells to clone many B-plasma cells. The B-plasma cells then release antibodies specific to that antigen, which then target the antigen and deactivate it by forming an antigen-antibody complex.

 

[Lordie]

This will make me sound like an idiot, heh - but is the Cerebrum basically the WHOLE brain? Diagrams confuse me! I know of specific functions of parts of the brain...but, is it basically the whole brain?

 

[katie tully]

No the cerebrum is not the whole brain, but it makes up most of the brain.

To clarify this for you;
It's divided into the 4 lobes. So when you refer to the cerebrum as a whole, you're integrating all of the lobes. But then each lobe can be referred to separately.

The Cerebrum: The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe.

The cerebellum is the 'small brain' at the base of the posterior side of the brain.

 

[Lordie]

No the cerebrum is not the whole brain, but it makes up most of the brain.

Hmm. So, "The cerebrum makes up about 85 per cent of the weight of the human brain.", sounds a little more than just the front?

Well, basically, we can talk about the Cerebrum, the cerebellum, and the medulla - just the Cebrum(Most of the brain), medulla(part at the base of the brain), and the Medulla(controlling breathing etc.) Is that it? Then speak of specific functions of these three parts?

 

[katie tully]

Yes I worded that badly.

The cerebrum is the part of the brain that incorporates the regions, which all have their specific roles.
The cerebellum is the 'small brain' at the base which controls sensory perception, coordination, that sort of thing.
The medulla yes, controls breathing, blood pressure. Those sort of homoestatic roles, which is what you would expect from its location.

Is this making a bit of sense?

 

[Lordie]

Thanks for the explanation.

So, say if a question asked, "Where is speech controlled?" Would an answer of, "The parietal lobe in the Cerebrum be correct?

If it asked, "Where is hearing controlled?" Is it the Temporal lobe?

If I was asked for sight, would I be correct saying it occurs in the occipital lobe of the cerebrum?

Thanks.

 

[katie tully]

Yes and no. The speech incorporates Broca's area and Wernicke's area. Wernicke's area is where the temporal lobe and the parietal lobe meet, and Broca's area is in the frontal lobe. So you wouldn't get full marks unless you said both of these, or mentioned Broca's and Wernicke's area's.

Hearing is controlled by the auditory cortex which yes, is located near the temporal lobe

Yes for sight.

 

[Undermyskin]

Well, probably more specific because it's not the whole lobe that controls such. You need to mention primary auditory cortex and auditory association area. etc

 

[Azurie]

Yes and no. The speech incorporates Broca's area and Wernicke's area. Wernicke's area is where the temporal lobe and the parietal lobe meet, and Broca's area is in the frontal lobe. So you wouldn't get full marks unless you said both of these, or mentioned Broca's and Wernicke's area's.

Hearing is controlled by the auditory cortex which yes, is located near the temporal lobe

Yes for sight.

Mynah birds don't like you

 

[katie tully]

Mynah birds don't like you

God they're shit birds.

I hope a spider eats them.

 

[Azurie]

God they're shit birds.

I hope a spider eats them.

They are like an organised gang of birds, they use their mob mentaility to eliminate any spiders,

 

[Darrow]

God they're shit birds.

I hope a spider eats them.

I lol
If they weren't so common, they wouldn't be bad looking birds