PLTW Unit 3.2 - Immune System

Describe Prions

infections, misfolded proteins that act as pathogens without containing DNA or RNA, Non-living, submicroscopic proteins

Example of Prions

CJD, Creutzfeldt-Jakob disease

Describe Virus

Non-living microscopic agents made up of an outer protein shell called a capsid, and either DNA or RNA

Example of virus

Flu

Describe Bacteria

Living, microscopic, single-celled, prokaryotic organisms

Example of bacteria

mycobacterium tuberculosis

Describe Protozoa

Living, microscopic, single-celled, eukaryotic, animal-like organisms

Example of Protozoa

Giardia Lamblia

Describe Parasitic worms

Living, multicellular, eukaryotic worms. Both microscopic and macroscopic varieties exist

Example of parasitic worms

Taenia tapeworm

describe fungi

Living, multicellular, eukaryotic organisms. fungi include yeasts, mildews, molds, and mushrooms. Both microscopic and macroscopic varieties exist

example of fungi

Tinea Pedis (athlete's foot)

main function of epidermis

acts as a protective barrier against external threats, including pathogens, uv radiation, chemicals, and mechanical injury.

main function of dermis

provide structural strength, elasticity, and support to the skin while protecting underlying tissues

main function of subcutaneous fatty tissue

primarily stores energy as lipids, provides thermal insulation, and acts as a cushion to protect muscles and bones from trauma.

describe skin

your biggest organ, so important that moderate burns on 30% of your skin can be life threatening

functions of skin

• protection-physical barrier

• keeps in water

• temperature regulation (sweat)

• sensory organ (feeling-pressure, pain, hot, cold)

• protects cells from uv radiation

• produce and secrete vitamin D

• keeping out pathogens

on the diagram what is #1

epidermis

on the diagram what is #2

dermis

on the diagram what is #3

subcutaneous fatty tissue (hypodermis)

what is sepsis?

the body’s immune system overreacting to an infection causing inflammation

what is severe sepsis

organs in the body begin to malfunction, blood pressure is low, and inflammation continues

what is septic shock?

extremely low blood pressure that does not respond to IV fluids

why is sepsis so dangerous

because without treatment it can lead to tissue damage, organ failure, or death

what is the main role of your lymphatic system?

the lymphatic system maintains fluid levels, absorbs fats from the digestive tract, protects the body from pathogens, and helps remove waste from the lymphatic system (lymph).

what is lymph

clear, watery fluid that the lymphatic system transports

explain why your lymphatic system is often lumped together with the immune system

they are grouped together because they work together to fight pathogens and protect the body from invaders

what is the difference between an antigen and an antibody?

an antigen is anything that stimulates an immune response, while an antibody is a protein made by B-cells that works to impair or neutralize pathogens

what is this showing

the relationship between an antigen and an antibody, antigen is the circle with triangles and antibodies is the y shape

compare and contrast antigens and antibodies

antigens:

• molecules found on the surface of pathogens (bacteria, viruses, etc)

• trigger an immune response

• tell the immune system that something is foreign to the body

both:

• involved in the immune response

• help the body identify and fight pathogens

• interact with each other during infection

antibodies:

• proteins made by B-cells

• bind to specific antigens

• help neutralize or mark pathogens for destruction

what is happening in this graph

how the body produces antibodies over time. the first exposure causes a slow primary immune response while the second exposure causes a faster and stronger secondary immune response.

how does this graph relate to vaccines

vaccines expose the body to an antigen so the immune system creates memory cells. this allows the body to respond faster and stronger if the pathogen enters again.

what are the structures in the primary immune response

antigens, B-cells, and antibodies

what are the structures in the secondary immune response

memory cells and antibodies that respond faster and produce more antibodies

describe what is happening at “E”

the antigen is engulfed by a macrophage and is presented to a helper t cell

describe what is happening at “D”

the helper t cells shows the antigen to the B cell

describe what is happening at “A”

B cells copy themselves to make plasma cells that produce antibodies specific to the antigen. Memory B cells form

describe what is happening at “C”

antibody concentrations begin to decline

describe what is happening at “B”

Plasma cells stop making antibodies, but memory B cells remain ready for another exposure to the antigen.

how does a vaccine work

a vaccine tricks your body into thinking you are sick by giving you part of the antigen, you make antibodies that are ready to go if you ever encounter the virus or bacteria “again”

why aren’t viruses considered alive

Viruses aren’t considered alive because they cannot grow, reproduce, or carry out life processes on their own.

how do viruses infect our cells

They infect our cells by attaching to a cell and injecting their genetic material, then using the cell’s machinery to make more viruses.

what was the purpose of the plaque assay lab

The purpose of the plaque assay lab is to measure viral load by observing plaques formed when viruses infect and kill cells oon an agar plate. this can be used to evaluate the effectiveness of medications over time.

what questions were we answering for the plaque assay lab

what is the effectiveness of 2 antiviral treatments for 2 different patients?

how does the plaque assay measure viral load

a plaque assay measures viral load by counting plaques on the agar plate. more plaques=higher viral load.

given the two graphs, which antiviral medication worked better

the one on the left

why did the one one the left’s, antiviral medication work better

this antiviral medication worked better because the viral load decreases quickly over time, meaning the medication is stopping the virus from reproducing faster. the graph on the right’s viral load increases first before going down so the medication is less effective at first

compare and constrast an antiviral medication and a vaccine

antiviral medication

• used after someone is infected

• stops or slows viral replication

• helps treat the infection

both

• helps the body fight viruses

• used to reduce illness caused by viruses

vaccine

• given before infection

• prevents disease by training the immune system

• helps the body recognize antigens and respond faster if exposed later

function of lens

focus light onto the retina so you can see clearly

function of iris

controls the size of the pupil to regulate how much light enters the eye

function of pupil

the opening in the center of the iris that allows light to enter the eye

function of cornea

the clear front surface of the eye that protects it and helps bend light as it enters the eye

function of retina

contains light-sensitive cells that convert light into electrical signals sent to the brain through the optic nerve (rods and cones)

function of optic nerve

carries electrical signals from the retina to the brain, where they are interpreted as images

how does light travel through the eye

light travels through the eye by passing first through the transparent cornea, then the aqueous humor, pupil (controlled by the iris), lens, and vitreous humor before hitting the retina. The retina converts light into electrical signals sent via the optic nerve to the brain.

viral replication decription of attachment

The virus attaches to the surface of the host cell. This attachment is highly specific to each virus, and viruses can attach to cells such as lymphocytes, monocytes, macrophages, and epithelial cells.

viral replication decription of entry

The virus DNA enters the host cell either by endocytosis, where the cell engulfs the virus, or by fusion with the host cell membrane.

viral replication decription of uncoating

Uncoating is the breakdown of the virus capsid, releasing the viral genome so its genes can be transcribed and replicated.

viral replication decription of replication

The virus uses the host cell’s machinery to copy its genome and make viral proteins and additional genome copies.

viral replication decription of assembly

New viral parts assemble into complete virions. Assembly can occur in the nucleus, plasma membrane, or other cell membranes depending on the virus.

viral replication decription of maturation

During maturation, final structural changes occur in the virion, making it fully infectious.

viral replication decription of release

The host cell releases new virions either by lysis (which kills the cell) or by budding, allowing them to infect new cells.

how do vaccines differ from antiviral medications

• in timing and purpose

vaccines: prevention - stop infection before it starts

antivirals: treatment - manage and reduce symptoms

what does TIME stand for

Temperature

Infection

Mental Decline

Extremely ill

why is TIME important

T: higher or lower than normal temp

I: signs and symptoms of an infection (swollen lymph nodes)

M: confused, sleepy, difficult to rouse

E: severe pain or discomfort

define innate (non-specific) immunity

• born with

• ex: skin

• work to keep anything outside us from coming in

describe acquired (specific) immunity

• not born with

• ex: vaccine

• acquired over a life time

• two forms:

  • active immunity: acquired after infection and recovery, or from a vaccine

    • passive immunity: acquired by a child from its mother through the placenta or through breastfeeding

list innate defense mechanisms

• tears

• mucus & cilia

• phagocytes

• stomach acid

• normal flora

• secretions

• inflammation

• fever

how does the phagocytes mechanism work

these cells patrol the lungs and eat and digest invaders (part of non-specific) (roam through your blood and vacuums/engulfs anything that should be there)

how does the inflammation mechanism work

• redness, swelling, pain

• histamine-increase in diameter of blood vessels

• blood brings WBCs to the area (phagocytes-neutrophils, macrophages, dendritic cells) (those are the three types of phagocytes)

how does the fever mechanism work

• caused by infection

• macrophages respond

• stimulate the hypothalamus to increase the body temp

• the immune system cells work more efficiently in warmer temps and to kill the bacteria that is making you sick

benefits of a fever

• increase the production of T cells (lymphocytes)

• promote tissue repair

• increase circulation of blood

• intensifies the effect of interferon (proteins that help your body fight viruses)

define antigen

• dictates antibody your body will make

• anything that stimulates an immune response

• how the body recognizes cells and noncells

define B cells

a type of lymphocyte (WBC) that matures in bone marrow and produces antibodies

3 types of pahgocytes

phagocyte: white blood cells that are part of the innate immune system. engulf and digest harmful pathogens.

1. neutrophil

2. macrophage

3. dendritic cell