Friday, February 22, 2008

Science Debate 2008

Have you seen this:

Would be great if you students got to see this.

Universities, corporations and a host of individuals are calling for a debate with all four of the remaining presidential candidates discussing critical scientific issues that impact everything from the environment to the economy., formed by two Hollywood screenwriters who had time to mull science recently while on strike, is an effort aimed at thrusting technology into the limelight.

One of the initiative's founders, Shawn Otto, said yesterday more than 17,000 American universities and the editors of nearly every major science publication in the nation have added their names to the Web site, encouraging the presidential hopefuls to debate key scientific issues.

"This is a nonprofit organization we set up to raise the profile of science and technology in our national political diaglogue," Otto said, adding that his initiative is now being co-sponsored by the National Academy of Sciences, the Institute of Medicine, the National Academy of Engineering, the Council on Competitiveness and the American Association for the Advancement of Science.

Yesterday, John Podesta, chief of staff for former President Bill Clinton, posted a video statement on YouTube echoing that science remains one of the nation's primary areas of focus. He called for a presidential debate "in charting a path forward on national security, on energy and climate change policy, really on the core fundamentals of our economic policy."

Otto said it would be "really fabulous" to see Democrats and Republicans on the same stage debating issues in science.

"All of us believe that almost every major policy challenge that the next president will face revolves around questions of science and technology," Otto said, referring to signers of his initiative.

"Ever since World War II, America has been leading in science and technology, and science and engineering have driven half of our economic growth."

But in the not-too-distant future, he added, 90 percent of all scientists will be living in Asia, causing a major "shift in intellectual capital."

James McCarthy on Science Debate 2008

John Porter on Science Debate 2008

Francesca Grifo on Science Debate 2008

Tuesday, February 12, 2008

Immune system

3rd line of defense in your immune system

the last say in the immune systems defense is lymphocytes.

B cells and T cells recognize the foreign antigens. B cells get their name because they're matured in the bonemarrow.
T cells get their name because....

So moving away from that...
B cells floating in blood and lymph check out antigens(the protein coat to identify cells) at random.
should they happen to find some one they dont recognize, or better yet DO recognize as a hazard, they release
the antibodies.
Antibodies stick to the foreign cell to slow it down acting as shackles.... but more acurately like...

thats guns

Once officially "netted" T cells call in the macrophages, and from there... its good game pathogen

B cells keep memeory of every antigen, so when it comes around again they know just how to fight back.


Action Of Protein Hormones
on a signal-transduction pathway
First, the protein hormone is reconized by the receptor and binds to it (signal). Then a secondary messenger system, and transduction (to transfer a message from one form to another) occurs. And finally a response from a cell is produced.

This all takes place on a signal transduction pathway. This requires the use of energy and different messengers.
Action Of Epinephrine

First the epinephrine binds to receptor than a message is sent to second receptor. It goes through a secondary messenger system and eventually sends a response to release glucose to blood.

2° Messenger System
has benefits
A 2° messenger system is a chain reaction, allowing for amplication and a very fast response.

Maintaing Homeostasis
negative feedback

When a specific body condition gets to high, a glad is signaled to produce a hormone, which lowers body condition. When condition gets too low, gland is signaled to produce a different hormone to raise body coondidtion.

An example of this is the Nervous System controlling Body temperature. When body temperature gets too high, brain sends nerve signals which make body sweat and dilate survace blood vessels, lowering temperature. When body temperature gets too low, brain sends nerve signals to make body shiver and constrict surface blood vessels bringing temperature back up.

Thursday, February 7, 2008

Better to breathe like a camel than look like one...

Dear Journal,

Today, at like, 6 o'clock or something, I was too lazy to get up, but I did anyway. So when I was up, I took a shower and got ready. Then I think I went to school. In Bio we learned some stuff I think, but I mostly just dazed off and thought about things. Like why peanutbutter is sticky, and how awesome it sounds when you rub two pickle slices together, 'cos you get that tiny little squeeky noise...


If I had paid attention (or stayed awake for that matter) in Bio, I probably would've learned about antibodies and stuff. But I was too lazy. So let's see, what do I know about antibodies.....

They're Greeeeeat!

Why you ask?

Without our immune system we would be.....

Our B-Cells, which produce antibodies, test every cell they come in contact with. They check its antigens, which are really like name tags. Antigens are present on EVERY SINGLE CELL....even our own! But, luckily for us, our antigens are recognized by our B-cells as our own, and they do not trigger a response.

However, when a B-cell comes in contact with a foreign invader, such as a virus, B-cells speed into action! Now there are two things that can happen:

1) If the virus has been in the body at an earlier time, the B-cells would already have made antibodies. If this is so, then the B-cells recognize the virus as an intruder, clone 1000's of B-cells with antibodies, and plasma cells release antibodies. Antibodies are "handcuffs" and they slow down the intruder for an easier destruction! How exciting!

2) If this virus is a new intruder, B-cells make antibodies for that specific virus or invader. At this rate, it takes a long time (about 10-17 days) to dispose of the virus, but antibodies have now been made, and are ready to leap like a crouching tiger!

YIKES! I feel bad for the virus the next time it tries to get in your blood!

Then of course, after these antibodies are made, the next time the virus enters, our immune system is able to recognize it so much quicker, and therefore destroy it uber quickly.

This graph shows the concentration of antibodies before and during the first exposure to the virus, and before, during, and after the second exposure. As you can clearly see, after the first attack, antibodies are at the ready, and can recognize, locate, and destroy the unwanted invader quickly and efficiently. This truly was an amazing adaptation.

Now comes the ever popular question: How can we produce millions of antibody proteins if we only have a few thousand genes?

AHA! The answer seems difficult. But behold! It is not!

If we had four decks of cards, and we picked 1 card from each at random, we could end up with a total of 7,311,616 possible combinations. That's alot of combos!

But seriously...

There are more than 52 selections to pick from in humans. We are only able to make these millions of combinations by picking different parts of DNA and putting them together. This process allows for an enormous amount of options.

And now......

For the moment you've all been waiting for.......

It's finally time......

Don't hold your breath......

Here it comes.....

OH NO!!!!


Vaccinations???? Oh well.

Vaccinations are really weakened or even dead forms of viruses. They cant harm us as much as the actual virus because, well, they're weak! These weak viruses allow our immune system to make antibodies specifically for the virus, without making us feel the full effects of the disease.
Vaccines are most successful against viral diseases.

Does this school look familiar? It should! This is Jonas E. Salk Middle School, and it was named after the man who invented the vaccination.

Here he is.

That's right. Jonas E. Salk.

Although Salk did not win a nobel prize for medicine, he was a brilliant man, and should be acknowleged for his findings, and specifically for his ending of the polio epidemic.

So if that is Active Immunity, then what is Passive Immunity??

The best example of passive immunity is when infants obtain antibodies from their mothers breast milk. This is specifically referred to as Maternal Immunity. Antibodies pass from the mother to the infant, and because the two are exposed to the same virus's and invaders, these antibodies are especially helpful.

Another way to obtain passive immunity is through injection. In these cases, antibodies are injected into the bloodstream. However, this type of immunity only lasts for a very short time. Hence the term, "Passive Immunity."

And what about the virus's that sneak into the body cells?
Well now, thats a different story for another journal entry.
Until next time.


Tuesday, February 5, 2008

Immune System

Immune/Lymphatic System

Avenues of Attacks
- Any opening in the body is a point of entry:
- digestive system
- respitory system
- urogenital tract
- breaks in skin
- Routes of attack: how foreginers move around the body once in
- circulatory system
- lymph system

- Why an immune system?
- Attack from outside
- organiams like to feed upon us due to our containement of fats,
lipids, and proteins
- we must protect our cells because cell wall protection has
been traded for mobility
- animals must defend themselves against invaders
- Viruses: HIV, flu, colds etc.
- Bacteria: Pneumonia, meningitis, etc.
- Protistis: amoeba
- Attack from the inside
- when own cells let go of the restrictions of their genitically programed jobs
- ex: cancer cells

- Animals evolved a lymph system
- The production and transprt of leukcytes traps foreign invaders
- Development of Red and White blood cells
- 3 Lines of Defense
- 1st line: barriers
- external defense
- skin and mucus membranes
- 2nd line: non- specific patrol
- broad internal innate defense; attempts to keep everything out
- attacks anything not recognized
- leukocytes = phagocytic WBC
- 3rd line: immune system
- specific aquired immunity
- inherit the ability but aquire defense
- lymphocytes (trained cells) and antibodies
- B cells
- make antibodies
- T Cells

- 1st line: External Defense
- Physical and Chemical Defenses
- non-specific defenders
- External Barrier
- epithelial cells and mucus membranes
- skin
- respiratory system
- digestive system
- uro-genital tract
-Chemical Barriers on epithelium
- Skin and mucous membrane secretions
- acidity in sweat
- tears act as a washing action
- mucus traps microbes
- saliva contains an anti-bacterial
- acidity in the stomach
- anti-microbial proteins
- lysozyme enzyme
- digests bacterial cell walls
- 2nd line: Internal, broad range patrol
- Innate, general defense
- Rapid response
- Patrolling cells and proteins
- they attack invaders that penetrate body's outer barriers
- leukocytes
- phagocytic (engulfing) white blood cells
- Complement system
-Anti-microbial proteins- in blood & plasma
- Inflammatory response

- Leukcoytes: Phagocytic WBC's
- attracted by chemical
- signals released by damaged cells
- enter infected tissue, engulf and ingest microves
- lysosomes
- Neutrophils
- most abundant WBC's
- Macrophages
- "big eater"- long lived
- take pieces of digested invaded and they destroy their cell with it as an alarm
- Natural Killer Cells
- destroy virus-infected cells and cancer cells
- Destroying cells gone bad
- Natural Killer Cells perforate cells
- release perforin protein
- insert into membrane of target cells
- forms pore allowing fluid to flow into cell
- no longer selectively permeable
- cell ruptures
- in flow of liquids into cell causing cell the rupture- apoptosis

- Anti- microbial protein
- 20 proteins circulating in blood plasma
- attacks bacterial and fungal cells
- form a membrane attack complexstamines and prostaglandins
- perforate target cell
- apoptosis
- cell lysis

- Inflammatory Response
- damage to tissue triggers local non-specific inflammatory response `
- release histamines and prostaglandins
- cappilaries dilate - more permeable - all in an attempt to "plug the leak"
- increase blood supply
- delivers WBC, RBC, platelets clotting factors
- fight pathogens
- clot formation

- Fever
-When a local response is not enough
-systemic response to infection
- activated macrophages release interleukin-1
- triggers hypothalamus in brian to readjust body thermostat to raise body temperature (fever)
- higher temperature helps defense
- inhibits bacterial growth
- stimulates phagocytosis
- speeds up repair of tissues
- causes liver and spleen to store iron, reducing blood iron levels
- bacteria need large amounts of iron to grow

Monday, January 14, 2008

Circulation in Animals

What truly is the point of Circulation? Why build such a complex system stretching through out the entire body? Below these questions shall be answered.

Exchange of Materials
The true point of the Circulatory system is to exchange, and transport materials from cells, and to cell, and to other parts of the body. This includes:
  • Oxygen
  • nutrients
  • Sugars, proteins, etc.
  • Water
  • Protective Agents(White blood cells, antibodies, platelet's, etc.)
  • Hormones
  • Carbon Dioxide
  • Urea
  • Water
Multicellular Animals need these essential materials, and to get ride of waste, but unlike unicellular organisms cant obtain it through diffusion alone, for this reason they need the Circulatory system, this network or highway for transport.
Types of Circulatory Systems
All Animals have some characteristics in common for their mode of circulation. The all contain blood vessels, a heart, and some type of fluid to transport materials in (blood for humans).
  • Invertebrates( insects, mollusk, anthropods) contain an open circulatory system which means they have no separation between blood, and interstitial fluid, instead they have hemolymph. This is a fluid that runs through their entire body touching the organs, and giving them nutrients.
  • Invertebrates( Octopie, earthworms, squid ) have separate blood from interstitial fluid. They have at least one heart, complex blood vessels, exchanging of materials between the blood, and the outside interstitial fluid.
  • Vertebrates( humans, clownfish , macaques ) also have a closed circulatory system. They have seperate blood from interstitial fluid, and complex blood vessels. The characteristics of vertebrates differ greatly through different evolutionary stages.
Evolution of heart chambers
The number of heart chambers differs greatly ranging from 2-4 in vertebrates. Having more chambers was a selective value because it is more efficient system, separating oxygen rich, and oxygen poor blood giving cells a fresh supply of concentrated oxygen. Having only 2 chambers, like a fish mixes the oxygen rich, and oxygen poor blood giving less overall oxygen to the cells. Since mammals, and birds are endothermic they also had a selective force to heave 4 chambered hearts so they could supply they needs of making heat by getting the supplies around faster, and with what is truely needed.

Blood Vessels
There are 3 main types of Blood Vessels found in the circulatory system of vertebrates.
  • Arteries are the blood vessels that carry blood away from the heart.
  • They are thicker than veins so that they can be able to make high pressure pumping of blood. Since it is pumping blood to the body it ne eds pressure to force the blood to move to the different parts of the body.
  • Has a narrow diameter to help keep high pressure within the vessels.
  • Veins are the blood vessels that carry blood towards, or back to the heart.
  • Low pressure so that skeletal muscle contractions are able to move the blood flow more easily towards the heart.
  • Wider diameter so there is less pressure.
  • Thinner walls for less pressure.
  • Valves in some of the larger veins help to direct blood flow by opening and closing leading blood to the heart.
  • Very small blood vessels that branch from the larger veins, and arteries but connected to the arterioles, and venules.
  • Very thin, only one layer of cells, endothelium.
  • Very permeable from thinness allowing the diffusions of molecules such as oxygen, and urea, and making for the connection for the transp ort of materials between cells, and the circulatory system.
The blood flow in capillaries can be controlled through the pre-capillary sphincters. They can retrict or allow blood flow through capillaries by either closing, or opening up. This is useful for when certain body parts are in need of blood, open, an d to close them when the part is in no need of blood.
The capillaries also exchange fluids, and solutes into the interstitial fluid through "bulk flow" or having a high pressure gradient. The interstitial fluid also flows into the capillaries through osmosis.
Lymphatic System
The Lymph system very much like the circulatory system and is parallel with it. The Lymph system is an open system, and helps collect, and return interstitial fluid to the blood. It also helps the bodies immune system greatly. It aids in the production of lymphocytes, and anti-bodies, also transporting these throughout the whole body as well as white blood cells to aid wherever they are needed. The system drops its load into the circulatory system near the vena cava, and right atrium.
Mammalian heart
The heart of your typical mammal is very similar, as we saw in the cow heart dissection. It consists of Pulmonary arteries, and veins which pump blood to and out the capillaries of the lungs, and the Aorta which is an artery that pumps blood throughout the body. The Coronary arteries give a supply of blood to the heart giving fresh supplies of oxygen. Many times this is blocked by buildup of cholesterol, and can cause a heart attack which can lead to needing bypass surgery, in which a alternate pathway from the aorta is made to the heart so it can get its supply of blood and not fail to pump.
The heart is made of up 4 chambers, the left and right Ventricle, and the left and right Atrium. These chambers are separated by four valves, made up of connective tissue that prevent back flow keeping the blood pumping in the direction it is needed. The sounds "Lub" and "dub" are produced from these valves closing, and opening. The Atrioventricular valves (AV) are between the atrium, and ventricle, and prevents blood from flowing in the atria when the ventricles contract. The Semi lunar valves are between the ventricles, and arteries and prevent blood from flowing into the ventricles from the arteries when the heart is relaxing.
A Cardiac cycle is one complete cycle of the hear pumping. This is when the heart contracts, and pumps, then relaxes and refills with blood. The contraction phase is called systole, and the relaxation phase is called diastole. This is the way someones blood pressure is measured to check if they have hypertension. The top number is systolic pumping(a higher number), and the bottom number is the diastolic pumping(lower number).

Jan. 10

Here are some key points we should have absorbed today

Animals get thier food by
Filter (suspension) feeding
-Substrate feeding
-Fluid feeding
-Bulk feeding

-Animals cannot make: elements; N, P, K, Fe, Na, Ca and NAD, FAD so they must take it in through food

peristalsis-push food along by rhythmic waves of smooth muscle contraction in walls of the digestive system.

Sphincters-muscular ring-like valves, regulate the passage of material between sections of digestive system.

Accessory glands- salivary glands, pancreas, liver, and gall bladder secrete digestive juices such as enzymes and fluid.

Stomach-stores foos, disinfects food, performs chemical digestion

Ulcers-caused by a bacteria overload in your stomach called helicobacter pylori cured with antibiotics.

Small intestine-chemical digestion, absorption through lining
-duodenum=most digestion
-jejunum=absorption of nutrients and water
-ileum=absorption of nutrients and water

-the small intestine is lined with villi and microvilli
the villi increase the surface area to absorb materials into the blood

large iontestine-re-absorb water
the large intestine is inhabited by countless bacteria including E. coli
the bacteria produce necessary vitamins for survival and help with digestion

Rectum-eliminate feces (extracellular waste) this waste has never been absorbed into the bloodstream.