Friday, Oct. 29th, 2010

How Allergies Develop


Develops in two stages:

1. The first exposure to the allergen causes sensitization (you get sensitive).

2. The following exposures of the same allergen cause allergy symptoms.

• Histamine – a chemical that reacts to an allergy

• We take anti-histamine when we get allergies to fight them off



The Details

1. Allergen enters the blood stream.

2. B cells make the antibodies

3. The antibodies attach themselves to the mast cell.

4. Allergen binds onto the antibodies on the mast cell.

5. Histamine is released and starts causing allergy symptoms.

Allergens usually tend to enter through the nose and the throat so symptoms are most abundant in these areas.

Anaphylactic shock – sudden releases of inflammatory chemicals into the body of people with extreme sensitivity to certain allergens such as:

• Bee stings

• Peanuts

• Shellfish

So what happens?

Blood vessels expand greatly causing a great drop in blood pressure, a condition also known as shock.

Anaphylactic shock can be fought off with injections of epinephrine (adrenaline).



Common Autoimmune Diseases

Rheumatoid Arthritis – causing damage and inflammation of bone joints due to T-cell attack

Juvenile Diabetes – a cell-mediated attack of insulin that produces cells in the pancreas

Multiple Sclerosis – T-cells attack the myelin sheath (fatty tissue) of neurons

Lupus – immune attack on skin and vital organs

Every disease or infection has a different reaction depending on how weak or strong your immune system is.



Immunological basis for organ/skin graft rejection?

Transplant Rejection – an immune system recognizes the donor’s cells or organs as foreign and starts attacking

Donors with self proteins that match the recipient’s as closely as possible are used in order to minimize rejection.

Drugs are used to hold back to suppress the immune system. The donors and recipients may not be related.



Immunodeficiency Diseases

Examples:

1. SCID (Severe Combined Immunodeficiency) – a case where someone does not have functional T and B cells; as a result, they do not have specific responses.

2. Hodgkin Disease – a type of cancer that affects the number of lymphocytes, affecting the T and B cells.

3. AIDS/HIV



AIDS (Acquired Immune Deficiency Syndrome)

HIV attacks the helper T cells that activate T bells and B cells.

Since 1981, AIDS has killed more than 20 million people, and 40 million people are living with the virus. Over 1/3 of the adult population in Africa has been infected as well.

Death is usually not a result of HIV, but because of other life threatening infections.



Next Scribe: Yunsu Yu

Immune System: T Cells, Allergies, Cancer, Immunity, Immune Response

10/28/10

Claire

Disease and the Immune System

After taking a quiz and finish the spice lab we went over these notes:

Supresser T Cells: get concentrations back to normal after the infection goes away

Cytotoxic T Cells: help protect body fro own cells if they become cancerous

-sometimes cancer is hard to fight because our bodies don't reconize our own cells as cancerous

Immune system has a "memory"

-our bodies remember the antigens we have encountered

-if we encounter the same antigen again, our immune system destroys them before symptoms occur

Immunity: resistance to specific invader

-can be done actively or passively

Active Immunity: body produces antibodies in its own defense

-if antibodies are produced, so are memory cells

2 ways:

-having disease

-vaccination: injection of weakened variant of disease-carrying microbe or one of it's components

Passive Immunity: receiving pre-made antibodies

-through mother's blood stream (baby's can't produce antibodies)

-through shot containing antibodies produced by another organism

Ex: Tetnus shot- gives you antibodies, not the pathogen because the pathogen is too dangerous and harmful, can get sick from it.

-have to get these shots more than once, no memory cells are produced

Primary Immune Response:

- first exposure of lymphocytes to an antigen

-takes days to produce antibodies-through colonal selection

-memory cells produced to remember antigen

-these are located in lymph nodes and live for decades

Secondary Immune Response:

-occurs when the same antigen is encountered again

-memory cells multiply leading to production of antibodies

-more effective than primary immune response

-person is symptom free

-could offer lifelong immunity

You can get infected by the same pathogen twice, but only get sick from it the first time because memory cells are produced

Immune Disorders: consequence of malfunctioning immune system

-allergies: sensitivity to antigens in environment

-how they are developed: 1st exposure to allergen cause sensitization, following exposures to same allergen produce symptoms

-Autoimmune Disorder: immune system fights its own molecules-vey bad

-Immunodeficiency Disease: body lacks part(s) of immune system

Next Scribe: Sally Y

October 27, 2010, B-Cells and T-Cells

Today, we watched two short movie clips.

One was about the role of an antibody.

• neutralization
• aggulination
• precipitation
• complement proteins

The other was about:

• humoral immunity- provided by B-cells, defends primarily vs. bacteria and viruses present in body fluids
• clonal selection

Notes: Page 21, 23, 24
Clonal Selection

• When an antigen enters the body fluids, it binds with B-Cells that have complementary receptors
• The B-cells are then activated; they grow and divide, creating effector cells
• These cells then secrete antibodies specific to that antigen
• plasma cells- make the antibodies
• memory cells- "remember," this is why you don't get the same exact infection again because your body produced the antibodies needed to fight that infection

T-Cells

• Cell-mediated immunity
• Respond to antigens that have already entered the body
• More "hands on" than B-Cells
• 3 kinds- Helper T-Cells, Cytotoxic T-Cells, and Supressor T-Cells

Helper T-Cells

• Macrophages engulf a microbe, produce antigens, and displays the foreign antigens on the cell membrane
• it is essentially saying "I found something and I don't think it's good!"
• The Helper T-Cell binds to the macrophage at the site and determines if it is good or bad
• If bad, the Helper T-Cell divides, produces memory cells, and stimulates activity of cytotoxic T-Cells

Cytotoxic T-Cells (Killer T-Cells)

• Identifies infected body cells and binds to them
• Discharges perforin which is a protein that creates a hole in the infected cell's membrane, causing it to die.
• This needs to happen because the infected cell has become a factory of pathogens and the body needs to have it shut down.

Homework:

• UP pgs. 47 and 57
• UP pg. 5 What is Ecology Good For (E.C.)
• Work on Lab Report, Due: 11/8
• The Test may be on Tuesday, but please still plan on Friday!!!

Next Scribe:

• Claire T

October 25, Immune System

Using cell signaling, a healthy cell makes proteins which inhibit viral replication, meaning it kills off the exported viruses that the bad cell releases.

2. Prostaglandins. Inscreases blood flow to the wound area = RED and WARM.
i. Also sends pain signals to brain. AH! Brain, help me!3. Pyrons. travel to the hypothalamus (it's in the brain and it analyzes your blood.) They cause a low fever which is GOOD because the heat makes the enzymes work faster.

III. Lymphatic System
A. Two main functions
1. To return tissue fluid to circulatory syste
2. To fight infection.
It's a highway of vessels that touches upon every part of your body so they can react fast when tissue is damaged.

Scribe: Aliza R.

October 21

Today, we viewed our dishes with agar in them that we worked on yesterday, and we put our results in our packets. Also, UP pg. 33 was completed, and it wasn't too hard, so there isn't much time needed to complete this task. We went over UP pgs. 31-32, these pages give you a better idea of how certain diseases differentiate between each other. Finally, we also completed the notes on bacteria that we left off from yesterday, and we took notes until the page entitled:
"Nonspecific diseases". So, if you wish to look at the notes, go into moodle under Mrs. Andrews' name, and the notes should show up.

This hereby concludes today's blog

next scribe - CJ

October 20th

o Set up Bacteria lab (UP pg. 19-25)
o Chapter notes- (pg. 10-top 13)

We looked at some important notes
Bacteria Cell:o They have no nucleus
o Most have cell wall exterior to plasma membraneo 50% are Motile (can move)
o Sessile- stationary

3 types of bacteria:o Cocci: spheres
o Bacilli: rod-shaped
o Spirochete: spiral-shaped

Bacteria Reproduction:o Can reproduce if conditions are favorable
o Their cells divide through binary fission
conjugation - sexual reproduction with 2 different bacteria cells
Endospore:o Can survive extended periods in harsh conditions
o Lack of water/ nutrients
o Extreme temperatures
o Most are poisons
o Found in some prokaryotes
o Outer cell produces the Endospore
o Outer cell may disappear, but Endospore survives
o Some can remain like this for centuries

Impact of Prokaryotes on Humans:o Disease- causing Bacteria
o Exotoxins: poisonous proteins secreted by the bacteria cells
o Often causes vomiting and diarrhea
o Endotoxins: chemical components of the cell wall on the cell
o Often causes fever, aches, drop in BP

Power of Antibiotics:o Zone of Inhibition: the areas where the growth of bacteria is prevented (inhibited) by an antibiotic or other substance

next scribe - Skyler

October 18th

Today we learned how we get sick. Pathogens are one way to get sick.
Viruses are considered both life and non life, since they ahve characteristics of both.
Life: Highly organized with genes
Non-Life: not cellular, cannot reproduce on own

Viruses infect a living cell. one way they do this is the lyctic cycle, where DNA is injected by virus into host cell to produce copies of virus.
DNA viruses usually reproduce in host cell's cytoplasm, sometimes in nucleus.
Prokaryotes have been around for 2 billion years.

Next Scribe - Nick