microorganisms in relation to human health: chapter 4

Superbugs

strains of bacteria, viruses, parasites and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause.

stratum corneum

The ________= the outermost layer of the epidermis.

Bacteria

________ penetrate the skin via a wound.

Perforin

a protein, released by killer cells of the immune system, which destroys targeted cells by creating lesions like pores in their membranes.

→ immunesystem

Via antigens ________ can recognise foreign cells and viruses= T- and B- lymphocytes → recognise antigen.

Non-specific defense

the bodys first line of defense against diseases.

T cells

________ produce signaling molecules → stimulate B- lymphocyte production.

Epidermis of body cavities

________ is much thinner than the other skin but is also in direct contact with the outside world →mucous glands protect it →create a thin layer of mucus to prevent access to the underlying tissue.

Cell membrane lymphocytes

________ have receptor molecules →ability to bind to the antigen= key- lock- principle.

Skin

________= a barrier with the outside world → protects the body in 3 ways of parasatic microorganisms.

Phagocytosis

The process by which a phagocyte (a type of white blood cell) surrounds and destroys foreign substances (such as bacteria) and removes dead cells.

Macrophages

specialised cells that are involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms.

example

MRSA

example

1

via antigens → immunesystem can recognise foreign cells and viruses = T

and B-lymphocytes → recognise antigen

Natural killer cells/ NK-cells

a special type of white blood cells that produce perforin that open and drain infected body cells

give the functions of signaling cells

1. attract macrophages and activate NK-cells 2. warn other cells to create protein to prevent multiplication of microorganism

specific defense

consists of mechanisms and agents that target specific antigens

antigen

a specific molecule (a protein) found in the cell membrane of all cells of any organism (including in the protein coat of a virus)

How to keep or increase resistance ?

get enough sleep; excercise regularly; have a balanced diet; avoid smoking, drugs and excessive alcohol consumption; be cautious with the use of medicines

What is the difference between active and passive immunisation?

active immunisation encourages the production of antibodies and memory cells while passive doesn't

How does the body build memory?

by producing memory lymphocytes which causes a faster detection and also a faster reaction from the immunesystem -> no sickness -> immunity

examples of non-specific defense

sking, mucous membrane, white blood cells and signaling molecules

function B-cell

recognise antigens → produce antibodies → bind with antigen → create antigen antibody complex →macrophages clean it up

functions T-cells

1. have membrane receptors to recognise infected cells → bind with it → perforate cell → cell dies 2. T-cells produce signaling molecules → stimulate B-lymphocyte production

How come superbugs exist ?

They are mutants who after frequent contact with antibiotics for example changed their DNA -> become insensitive to antibiotics -> break it down or render it harmless

How does the skin protect the body?

1. via the stratum corneum 2. the sebaceous and sweat glands secrete acidic and antibacterial substances 3. the body's bacteria compete with foreign bacteria

How do the mucous membranes protect the body

the mucous glands create a thin layer of mucus that prevents microorganisms to gain access to the underlying tissue

How do the white blood cells and cell signaling protect us ?

macrophages, natural killer cells, signaling molecules

examples of specific defense

T-lymphocytes, B-lymphocytes