Immunity l: Innate

Innate

something that just happen in the body

Despite being surrounded and inhabited by microbes, why are we not constantly infected?

because not all microbes are pathogenic and for those who are harmful we have defenses against them

If your bodi’s defences for a microbe fails what results from it

infection

The immune system

a variety of cell and molecules in the body

Goal of the immune system

to eliminate invaders and abnormal cells

Pathogens

microbes and infectious agents that cause disease by evading, destroying or overwhelming defenses

Vertebrates have 2 components of immune system

innate defense and adaptive defense

Innate defense

present at birth

First line of defense

active without previous exposure

Adaptive defense

acquired after exposure

responds to antigens

involve B cells and T cells

Antigens

molecules that stimulate an immune response

Types of barriers

skin, mucous membrane, and flushing action

Keratinocytes in epidermis

makes keratin

Keratin

fibrous proteins that make up hair, skin, and nails.

Desquamation

constant sloughing (cleaning/removing) of the other skin layer

Purpose of desquamation

to remove microorganisms that may have attached to the outer skin layer

Epithelial cells

form tight junctions to prevent invasions

Glands on the skin helps with

sweat and sebaceous glands

Sweat on skin causes

high salt concentrations

Sebaceous glands create

oils, which are fatty acids that created low pH

The main purpose of the glands on the skin is to create

An unfavorable condition for microbes

Mucous membranes lines

cavities and openings

Line cavities and openings are located in the

the respiratory, digestive, urogenital tracts, the conjunctiva of eye and nostrils

Line cavities and openings are

warm, moist, and not covered by keratinized cells, thus favorable for microbes

Components of the mucous membranes include

epithelial cells and mucus

Epithelial cells are

tight junctions

Mucus has

Mucins secreted by goblet cells help prevent microbe movement trapping them

Mucins

hydrated glycoprotins are slimy

Mucociliary clearance

Ciliated epithelial cells that moves mucus and particles out of passages located in respiratory tracts and vagina

Bacteriophages

are embedded in the mucus of the respiratory tract and attack bacteria

Bacteriophages purpose is to

control bacterial population growth in humans

Flushing actions include

coughing, sneezing

vomiting, diarrhea

tears, saliva

urinary flow

blood flow at wounds

Barriers are excellent at ____, but

keeping microbes out; minor breaches can occur

Example of a breach of barrier

burns, cracking of dry skin, insect bites, paper cuts

If there is a breach in barrier

microbes may enter the blood or connective tissue

Types of chemical defenses

lysozymes, transferrin, lactoferrin, defensins

Lysozyme

enzymes found in fluids of the body (tears, saliva, mucus) that cleave peptidoglycan

Transferrin are found in ___ and its purpose is

plasma (blood) protein; binds to free iron, inhibiting bacterial growth in the bloodstream

Lactoferrin are ____ and its purpose is to ___

proteins found in saliva, mucus, and milk; binds to iron to inhibit bacterial growth

Defensins are ____

Small peptides found in mucus and extracellular fluids

An example of defensins is

produce pores in pathogen membrane

Cells are located ____ in ___

throughout the body; blood and other tissues

Blood is ___% liquid/__ and ___% formed elements

60

plasma

40F

Formed elements of the blood are

the cell and cell fragments

Blood is derived from

Pluripotent stem cells in bone marrow

pluripotent stem cells are

cells that have the ability to become any type of cell

Erythrocytes

Red blood cells

Platelets

fragments of cells; involved in blood clotting

Leukocytes

white blood cells; involved in innate and adaptive immune response

Phagocytes are ___ and their purpose is to ___

cells that engulf other materials; circulate throughout the body to remove dead cells and other cellular debris and to protect skin and mucus membranes against invasions

Neutrophils are

a type of phagocyte that is continuous releases from the bone marrow, circulating in the body, are the first to arrive at site of infection

Neutrophils eats ___

bacteria and small particles

Neutrophils live for ___ and when they die they can ____

1-2 days; accumulate and become pus

Monocyes

migrate from bone marrow into blood and then mature into macrophages

Compare Neutrophils and monocytes

Monocytes take longer to reach the site compared to neutrophils, but they arrive in larger numbers

Chemotaxis

allows phagocytes to find microorganisms

Pattern recognition receptors

are found on phagocytes are recognize MAMPsM

MAMPs

micro associated molecular patterns: molecular patterns that are unique to microbes (peptidoglycan, flagellin proteins

TLRs (toll-like receptors)

10 known in humans, example of PRR

TLR4 recognize

LPS component of Gram-negative cell walls

TLR 3, 7, 8 recognize

nucleic acids of viruses

Seq the process of phagocytosis

l. Adherence

ll. Ingestion

lll. Chemotaxis

lV. Digestion

lll > l > ll > lV

Binding of PRR and MAMPs triggers

The release of attractants, histamine, and cytokines

Attractants

brings phagocytes to a specific region

Histamine

is released by basophils and most cells to promote and inflammatory response

Cytokines

activate cells in an inflammatory response

Adherence allows

phagocytes to bind to specific molecules on the microbe's surface

Ingestion/engulfment

Pseudopodia surround the microbe to enclose the microbe within a cytoplasmic vacuole made from the plasma membrane (phagosome)

Digestion

The lysosome fuses with phagosome to form phagolysosome

The digestive enzymes and defensins destroy microbes

Inflammation is activated by __ and characteristics include

tissue damage; heat, redness, edema(swelling) and pain

Sequence inflammation

l. Damaged cells release bradykinins

ll. Most cells release histamine to nearby vessels

III. Macrophages and neutrophils released

lV. Increased blood flow

ll > l > lll > lV

Histamine

released by nearby cells

Capillaries are dilated, increasing blood flow, causing the area to become swollen, red, and warm to the touch

causes skin to be more permeable, allowing more fluid into interstitial fluid (edema)

Bradykinins

causes pain

Macrophages and neutrophils

phagocytosis of pathogens and clear cell debris while secreting cytokines to promote blood flow to the site of injury

Increased blood flow

causes the area to be red and warm

delivers phagocytic WBCs, nutrients, O₂, and antimicrobial peptides

Inflammation can be local or

involve the whole body; fever

Fever

elevated body temp, above optimum temp for pathogens, interfers with growth and replication of pathogens

Host increases rates of phagocytosis, breakdown by lysosomes, and feels unwell.