10.3 - Human Immune System

_____ are harmful microscopic enemies that can cause disease

pathogens

what are leukocytes?

white blood cells (WBCs)

leukocytes are produced by _____ in red bone marrow

hematopoiesis

(red bone marrow tends to concentrate at the end of long bones (epiphyses))

lymphocytes are special types of leukocytes that originate from ____ but end up concentrate in _____ tissue

bone marrow; lymphatic

lymphocytes can produce _____ & _____

antibodies; cytokines

what are some examples of lymphocytes?

B and T cells

what are the 2 types of immune responses?

innate and adaptive

the _____ immune system is a quick, nonspecific immune response

innate

a human's outer barriers to infection (such as skin) are the first layer of _____ immunity

innate

innate immunity

1. skin

2. cilia

3. stomach acid

4. symbiotic bacteria

what are some of the outer barriers, which are a part of innate immunity? - skin

1. thick epidermis; dermis; hypodermis (subcutaneous)

2. mucus membranes , secrete lysozymes

3.sebaceous glands

pathogens are unable to penetrate which integument layers?

epidermis; dermis; hypodermis (subcutaneous)

mucus membranes in the skin function to secrete _____ and trap pathogens

lysozyme

lysozymes are antimicrobial protein enzymes found in tears, saliva, and mucous, which _____ break down bacterial _____

nonspecifically; cell walls

sebaceous glands of the skin secrete _____, which serves as physical barrier

oil (sebum)

the fatty acids in sebum are _____ & _____

antimicrobial; nonspecific

what are cilia?

hair-like projections that sweep away unwanted invaders

- found in respiratory tract

stomach acid is an _____ barrier of the innate immune system, which _____ kills microbes with low* pH

internal; nonspecifically

_____ bacteria out-compete their more hostile relatives and are an _____ barrier to infection

symbiotic; internal

What occurs when the physical barrier is penetrated?

innate immunity continues with the inflammatory response

mast cells are a type of _____ that sits in tissues

leukocyte

injured tissue and mast cells work together to release _____

histamine

histamine - functions

1. Dilate nearby capillaries —> increase blood flow

2. Make capillary walls more permeable —> fluid and immune cells leak out to the site of

injury.

histamine dilates capillaries (and makes their walls more permeable) near injured vessels, which brings more blood to the injured area - why is this beneficial?

fluid and immune cells leak out to the site of injury

(inflammatory response)

what are the 5 signs associated with inflammation?

Swelling

Loss of function

Increased heat

Pain

Redness

(SLIPR)

heat is an inflammatory sign, which results from _____ and _____

dilation of capillaries; increased blood flow

_____ is an inflammatory sign, which occurs due to the dilation of capillaries

redness

(more blood = red color)

_____ is an inflammatory sign that occurs by permeable capillaries

swelling

(fluid accumulation due to leaky blood vessels)

_____ pain happens right at the time of injury, and it is caused by nerve endings

sharp

_____ pain is felt after the time of injury, and it is due to inflammation

slow, throbbing

- the swollen areas exert pressure on free nerve endings, which causes a continuous pain.

what are the indirect outcomes of inflammation?

loss of function due to swelling and pain

fever

_____ is a systemic response to hinder the growth of (or kill) pathogens

when capillaries dilate during the inflammatory response, leukocytes tend to adhere to the endothelial cells that line the vessels - what is this called?

margination

What is diapedesis?

the process of cells moving from capillaries to tissues

what is chemotaxis?

the process of moving to a location in response to a chemical signal

what are the 5 types of leukocytes in order of abundance?

(Never Let Monkeys Eat Bananas)

Neutrophils

Lymphocytes

Monocytes/Macrophages

Eosinophils

Basophils

_____ are the most numerous leukocytes

Neutrophils (Never)

- 40- 70% of WBC

Neutrophils (Never) act as _____ in the _____ immune system

phagocytes; innate

- part of innate response because neutrophils eat all pathogens nonspecifically

which Lymphocytes (Let) are innate and which are adaptive?

natural killer (NK) cells = innate;

- B and T cells = adaptive

- lymphocites all require targets

natural killer (NK) cells

- innate Lymphocytes (Let)

- attack and kill 1 ) virus-infected cells 2) cancerous body cells

natural killer (NK) cells vs. B, T Cells

NK - do not require activation, innate

B, T cells - needs activation, adaptive

NK cells are innate Lymphocytes (Let) that secrete _____ & _____ to fight enemies

perforin; granzymes

(NK cells (innate) and CD8/cytotoxic T cells (adaptive) are both Lymphocytes (Let) that secrete perforin and granzymes)

_____ is a protein that creates a pore to perforate pathogen membranes --> causes cell lysis

perforin

(NK cells (innate) and CD8/cytotoxic T cells (adaptive) are both Lymphocytes (Let) that secrete perforin and granzymes)

granzymes

proteases, which stimulate apoptosis, which is useful for virally infected/cancerous cells

-

(NK cells (innate) and CD8/cytotoxic T cells (adaptive) are both Lymphocytes (Let) that secrete perforin and granzymes)

a _____ is an enzyme that breaks down proteins and peptides

protease

_____is programmed cell death

apoptosis

Monocytes (Monkeys) are a part of the _____ response

innate

(nonspecific)

monocytes vs. macrophages

- Monocytes (Monkeys): immature, in blood vessels

- macrophages: mature once they cross over into an infected tissue via diapedesis

macrophages are mature Monocytes (Monkeys) that act as phagocytes and function as _____ to activate adaptive immunity

antigen-presenting cells

Eosinophils (Eat) are a part of the _____ immune response

innate

(non-specific)

how are monocytes/macrophages similar to neutrophils?

both are phagocytes, nonspecific

Eosinophils (Eat) contain _____ in their cytoplasm, which can be released to kill pathogens (especially effective on ___)

granules;

parasites

Basophils (Bananas) are the _____ numerous leukocyte

least

Basophils (Bananas) contain _____ (like Esoinophils) and have a similar function to _____

granules; mast cells

what are the 2 important components of Basophil (Bananas) granules?

histamine; heparin

heparin

is a component of Basophil (Bananas) granules, which prevents blood from clotting too quickly

mast cells and Basophils (Bananas) are made in _____ and then leave to circulate in the _____

red bone marrow; blood

When released into blood, basophils (Bananas) are _____ in the blood, while mast cells are _____ in the blood

basophils --> mature;

mast cells --> immature

dendritic cells =

- use _____ to observe local environment

= surveillance guards roaming in tissues detecting potential threats.

-

pinocytosis

pinocytosis is a type of endocytosis that is also known as _____

cellular drinking

(endo-/exocytosis are active transport mechanisms)

dendritic cells are part of the _____ immune system, but they travel to lymph nodes to activate _____ immunity

innate; adaptive

(dendritic cells are antigen presenting cells)

dendritic cells and macrophages are both ___

antigen-presenting cells

-then BOTH migrate to lymph nodes along to activate the adaptive immune response

what links innate and adaptive immune systems?

dendritic cells

macrophages

inteferon

interferon is secreted by _____ cells

- purpose:

virus-infected

- to warn non-infected cells in vicinity by binding to non-infected ones

_____ binds to non-infected cells to warn/prepare for viral attack

interferon

interferon activates _____ cells, which further activates adaptive immunity

dendritic

complement system contains a group of _____ that help the immune cells battle pathogens

30 proteins

complement system - innate / adaptive??

innate

how do complement system proteins activate each other

cascade series of activation through release of cytokines

functions of activated complement system

1. opsonization

2. amplify inflammatory response

3. lyse pathogen membrane

opsonization is a feature of the complement system - what does it do?

complement proteins coat the surface of an invader, making them more prone to phagocytosis

- bind complement protein C3b to antigens to improve their "cell eating"

complement system - inflammatory response

certain proteins can bind to mast cells to trigger a stronger histamine release

the complement proteins are activated by _____

IgG and IgM

what are the two mechanisms for complement system activation?

classical and alternative pathways

(don't memorize requirements for each)

describe complement system lyse pathogen membranes

some proteins form a membrane attack complex (MAC) which specifically functions to poke holes in pathogen membranes

- once holes created --> fluid and salts can go into the pathogen --> cell lysis

if innate immunity isn't sufficient to protect against pathogens, what joins?

adaptive immunity

_____ immunity is a specific immune response for specific antigens, and it has _____

adaptive; memory

antigen

is a marker from a foreign molecule that helps distinguish between self/non-self cells

how does the body distinguish between self and non-self cells (in addition to antigens)?

major histocompatibility complex (MHC)

all nucleated cells contain MHC class _____ molecules on their surface

1

antigen presenting cells contain both MHC class _____ & _____ molecules on their surface

1; 2

true or false - genetically unique individuals contain unique MHC 1 molecules

true

exception: identical twins have the same MHC 1

what are the proteins of a MHC class 1 molecule?

alpha 1, 2, 3 and beta-microglobulin protein chains

what are the proteins of a MHC class 2 molecule?

alpha 1 and 2; beta 1 and 2

why do transplanet rejections occur?

different MHC 1 molecules will be labeled as a foreign antigen on the donor organ

transplant patients must take _____ on a life-long basis

immunosuppressants

- to lower/eliminate the immune system's response towards the foreign organ.

- doing so also makes these patients more susceptible to general infections.

in autoimmune diseases, the immune system attacks _____

self-cells

_____ act as a bridge between innate and adaptive immunity

antigen-presenting cells (APCs)

macrophages and dendritic cells are _____

antigen-presenting cells (APCs)

macrophages and dendritic cells contain MHC class _____ and _____ - why?

1; 2

they are antigen presenting cells (APCs)

MHC I vs. II

MHC I : found on all nucleated body cells

- mark for "self"

- foreign MHC I molecules are deemed as antigens (i.e. organ donations)

-

MHC II: found only on APCs

a _____ is the section of an antigen that is recognized by immune cells

epitope

B and T cells are adaptive _____

Lymphocytes (Let)

what are the 3 main types of Lymphocytes (Let)?

NK cells (nnate); B and T cells (adaptive)

B cells stay and mature in the _____, while T cells go and mature in the _____

bone marrow; thymus

_____ are involved with antibody-mediated adaptive immunity (humoral immunity)

B cells

each B cell has 1 type of _____ that is specific for 1 type of antigen epitope

B cell receptor (BCR)

what can B cell receptors (BCRs) bind to?

free-floating antigens or antigens presented by APCs

what happens after a B cell binds to an antigen?

it becomes activated and then divides to make copies of itself

describe the clonal selection model for B cells

B cells have unique BCRs to specific antigens. If those antigens are present, only the B cells with the BCR for antigen binding will amplify (one antigen, one B Cell)