Week 9 - immunity

Innate immunity is also known as

non-specific immunity

Non-specific immunity describes the body's

first and second line of defence

Types of 1st line of defence in non-specific immunity

protective mechanical mechanism and design. bactericidal substances in secretions. cells capable of destroying forgein material. circulating substances

Give an example of the 2nd line of defence in the body

inflammatory response

Adaptive immunity is also known as

specific immunity

Specific immunity can be described as the Aquisition of immunity as

we gain this after birth - specific antigens lead to antibodies

Specific immunity is concerned with

the recognition of certain forgein material (antigen)

An antigen is

a foreign protein which elicits a specific response

The human body’s external and internal defences act continually to maintain cellular homeostasis by

combating harmful environmental agents

4 agents that may trigger an immune response:

pathogenic microorganisms. antigens of pathogens. pathogenic secretions (toxins). environmental pollutants (dust particles)

Lymph is

tissue fluid inside lymphatic vessels and is produced throughout the body (2-4l in 24hrs)

Lymphatic vessels merge forming

larger vessels then into 2 large ducts (right lymphatic and thoracic ducts)

The 2 large ducts drain lymph back into the main

vascular system in the neck region in subclavian and jugular veins

The lymph system is activated in response to

microbes

Which organ are essential in producing lymphocytes T and B?

bone marrow. thymus and fetal liver

What happens if breast cancer infects the lymphs near?

the cancer can metastasize to other places in the body

The thymus gland is thought to continue to function throughout the lifespan but its effectiveness of its lymphocytes in response to antigenic insults

declines

Name some 1st line of defence features that protect the body:

intact skin and mucus membranes. digestive tract. eyes - reflexes and tears. waxy ear secretions. urination. acidity in the vagina. placenta. memory and stress response.

Name ways that microbes can enter the body:

invasive devices. wounds. catheters. faecal oral route. inhaled droplet. ingested.

Name some functions of the skin:

protection-physical and chemical (melanocytes). sensation. temperature regulation. communication. synthesis of vitamin D. excretion. Energy and water reserve. absorption

The cells of the epidermis are around 95% epithelial cells called

keratinocytes (tough protein)

There are how many layers of epidermis?

five

new cells are produced in the

basal layer and are pushed up to the surface getting squashed in shape.

Dead keratinocytes are shed

constantly

Psoriasis is when keratinocytes are pushed up

too quickly

Langerhans engulf bacteria

fighting off infections. the pH of skin is slightly acidic which helps

Melanocytes are responsible for

surface cover of the skin - protects skin against UV rays

The epidermis is around how thick?

1mm

The epidermis does not contain any

blood vessels but is nourished by the capillaries in the dermis below

Skin adaptations which mean les water is lost:

outer visible layer i toughened by cells containing waterproofing coating keratin and the lipid matrix if not easily penetrated by water

Surface renewal of skin takes how many days?

15-30

The dermis is a

strong flexible connective tissue

How does the skin chemically discourage microbes?

it contains sweat and sebum at a pH of 5.5 discouraging alkali microbes

sweat contains bactericidal chemicals like

antibodies and lysozymes

Detergents and organic solvents increase skin

permeability and dissolve the lipid matrix making cells swell causing more skin infections if regularly soaked

What controls variations in skin colour?

genetics. albinism and latitude

A pre-term baby can suffer significant water less through very thing

uncornified skin

In utero at 17-20 weeks foetus exfoliated layer vernix caseosa gives protection to the

fetal skin from amniotic fluid and urine

at birth skin is sterile but soon colonised by

bacteria and fungi from environment

sweat glands are present at birth and start to function normally from

2 years old

As we age the rate of epidermal cell replacement

slows

Skin thins and becomes susceptible to what when we get old?

bruises and injuries

as we age lubricating substances produced by the skin

decline and skin becomes dry and itchy

as we age the dermis elastic fibres clump what together leading to what?

collagen gets reduced leading to wrinkles.

reduced melanocytes in elderly leading to

enhanced risk of skin cancer

cold intolerance in elderly is due to the

subcutaneous fat layer diminishing

lymphocytes are sensitive to

abnormal antigens on otherwise normal cell membranes

The inflammatory response is a local

defensive response to tissue damage

the 2nd line of defense's function is to eliminate the cause of tissue damage by removing

the consequent dead cells and restoring the consistency of the internal environment

The non specific immune response is the same for

any cause

the appearance of a non-specific response depends on strength of

stimulus and pathogenicity of microbes

Causes of inflammation can be one of 3 things:

physical or chemical or microbiological (measles)

Clinical features of an immune response:

redness. hot. swelling. discomfort. loss of function

Damaged tissue causes what to be released causing an inflammatory chemical release?

histamine

damaged tissue causes blood flow to

increase by increasing capillary permeability

Damaged tissue causes what to be activated?

phagocytes. clotting and specific defences

some signs and symptoms of infection include:

chills. increase RR. loss of appetite. enlarged and tender lymph nodes. confusion. behavioral changes in children. increased temperature

Phagocytes are also known as

white blood cells first line of cellular defence

Phagocytes are classed as microphages or macrophages which leave the blood stream and enter

peripheral tissue to engulf microorganisms

Macrophages called monocytes migrate to

areas of infection and located in key tissues

A complement consists of special proteins which interact to:

inactivate viruses. destroy bacterial cell walls. stimulates the inflammatory response and cause chemical attraction to phagocytes

Interferons are proteins which are produced by

a virus infected cell

Interferons provide some protection to

intact cells from viral attack

Natural killer cells respond to specific antigens by targeting cells with

altered surface membrane activity which happens without the need to interact with other antibodies = first line of defence in specific immunity

an abnormal elevation in core temperature is caused by

cytokine-induced upward displacement of hypothalamus set point

Pyrogens exogenous trigger the body to produce endogenous pyrogens which

adjusts hypothalamus set point to increase body temperature which is important for our body's defence system

Respiration and heart rate elevation increases

metabolic rate and oxygen demands and the use of body protein as an energy source.

the humoral response is a system of

specific immunity

the humoral response leads to a production of

immunoglobulins/antibodies

antibodies produced in the humoral response are created by

plasma cells (modified B lymphocytes)

B lymphocytes fight

bacterial infection

Cell mediated system is a

specific immunity response

the cell mediated response uses

T lymphocytes capable of destroying antigens

T lymphocytes protect the body from tumors and can cause

transplant rejection

Lymphocytes are formed of what percentage of WBCs?

25-45%

Lymphocytes arise from

bone marrow

20% of lymphocytes are

B cells

70% of lymphocytes are

T cells formed in the thymus

above 5% of lymphocytes are

natural killer cells

B cells originate from

stem cells

B cells are processed in

bone marrow

When B cells are presented with antigens they

differentiate into memory cells and plasma cells

Plasma cells produce

antibodies

T cells originate from

stem cells

T cells are processed in the

thymus

When T cells are presented with antigens they

differentiate into memory cells. killer cells. helper cells. suppresser cells and cytotoxic cells

Bone marrow immune function begin in uterus with

proliferation of haemopoietic cells at 20 weeks of gestation.

At birth B cells exist in bone marrow but are not

antigen specific yet

T memory cells increase to adult levels with peak at

1 and 6 weeks after birth

Antibodies can use opsonin by

coating of microbes with antibodies which enhances adhesion and phagocytosis

Antibodies can use lysins which causes

cellular rupture

Antibodies can use agglutinins which causes

immunogens t clump together

What is haemolytic disease of the newborn?

when a mother has a mix of Rh groups due to a previous pregnancy and in the next pregnancy if the foetus has a different Rh group to mother is can lead to attack of antigens = jaundice or stillborn

Natural active acquired immunity is gained when you are actually

infected by the organism stimulating lymphocyte response

Most vaccines are live attenuated vaccines so behave like the pathogen to produce a

good response

Killed vaccine give

poorer immune response.

Innate immunity is

present at birth

acquired immunity is gained after

birth as a result of the immune response and exposure to environment and immunisation

Active acquired is produced by the host after

natural exposure to the antigen - immunisation or illness

Passive acquired does not involve the hosts

immune system. maternal antibodies pass to foetus e.g. through breast milk