Chapter 37- CURRENT SLDES

Pathogens

to produce disease

• living : bacteria, protists and fungi

• non-living: viruses

• reproduce, spread, and harm their hosts

• staph infection, chloera, measles, tetanus, chicken pox, swine flu, covid

staphylococcus aureus bacteria (staph)

mostly found on the skin and in the nasal passage

• some strains cause fatal toxic shock syndrome or prolonged infections

What are the three major lines of defense in vertebrate animals?

Nonspecific external barrier → innate immune response → adaptive immune response

What is the Nonspecific external barrier

skin, mucous membranes

what is the innate immune response

phagocytic and natural killers, inflammation, fever

• affects vertebrates and non-vertebrates

• immediate speed of response

what is the adaptive immune response

humoral immunity, cell-mediated immunity

• delay of several days to 2 weeks speed of response

The skin

First line of defense: nonspecific external barriers

• outer surface consist of dry, dead cells filled with proteins similar to those in hair and nails

• secretions from the sweat and sebaceous glands contain natural antibiotics that inhibit microbial growth

Mucus membrane

First line of defense: nonspecific external barriers

• secrete mucus

• contains antibacterial proteins including lysozyme

phagocytes

neutrophils, dendritic cells, and macrophages

• surround, ingest, and digest foreign invaders and cellular debris by phagocytosis (cell eating)

neutrophils

white blood cells (leukocytes) that engulf invading microbes

dendritic cells

white blood cells that engulf invading microbes and present antigens to lymphocytes

macrophages

white blood cells that engulf invading microbes and present antigens to lymphocytes

Natural killer cells

white blood cells that destory infect or cancerous cells

Mast cells

connective tissue cells that release histamine; important in the inflammatory response

• inflamattion brings defense to injured tissue

B cells

lymphoctyes (a type of white blood cell) that produce antibodies

• memory B cells

• Plasma cells

memory B cells

offspring of B cells that provide turue immunity aginast invasion by the same antigen

plasma cell

offspring of B cells that secrete antibodies into the bloodstream

•Healthy cells display self markers called __________ proteins, which differ between species and between individuals within a species

the major histocompatibility complex (M H C)

_____ or _______ may lack or have altered MHC proteins

Virus-infected or most cancerous cells

•The adaptive immune response is produced by interactions among several types of cells:

• macrophages

• dendritic cells

  • lymphocytes

T cells

lymphoctyes that regulate the immune response or kill infected cells or cancerous cells

cytotoxic t cells

t cells that destroy infected body cells or cancerous cell

helpter t cells

T cells that stimulate immune responses by both B cells and cytotoxic T cells

memory t cells

offspring of cytotoxic or help t cells that provide future immuunity against invasion by the same antigen

Regulatory

t cells that suppress immune attack against the body’s own cells and molecules; important in preventing autoimmune diseases

Cytokines

stimulate cell division in lymphocytes during the immune response and stimulating the inflammatory response

Antibodies

–produced by B cells and their offspring, help the immune system to recognize invading microbes and destroy them

Complement

–proteins are mostly synthesized by the liver and circulate in the blood plasma

Steps of all adaptive immune resposnes

1.Lymphocytes recognize an invading microbe, identifying it as non-self

2. .They launch an attach

3. They retain a memory of the invader, allowing future infections prevention by the same type of microbe

–proteins, polysaccharides, or glycoproteins that can trigger an adaptive immune responses, are called _____

antigens (antibody-generating molecules)

Viral antigens

may incorporate into the plasma membranes

–Toxins released by bacteria

may be dissolved in the blood plasma, lymph, or interstitial fluid

IgM and IgD:

attached to the surfaces of B cells, triggers multiplication of B cells

IgG:

circulates in blood and crosses the placenta, protect newborn and provides long-term immunity

IgA

secreted onto digestive and respiratory tracts, and into saliva and breast milk; combats invaders entering via mouth and nasal passages, protects nursing infants

IgE:

drives allergic reactions

wo functions of antibodies

–Recognizing foreign antigens and triggering the response against invaders

–Helping to destroy the invading cells or molecules that bear the antigens

Humoral immunity:

produced by antibodies dissolved in the blood

Clonal selection

Fights invaders that are outside cells

cell-mediated immunity

produced by cytotoxic T cells which attack virus-infected body cells and cells that have become cancerous

Memory B cells

rapidly produce a clone of plasma cells, secreting antibodies that combat this second invasion

Memory T cells

produce clones of either helper T cells or cytotoxic T cells specific for the “remembered” invader

Acquired immune deficiency syndrome (A I D S) is the most common acquired immune deficiency disease

–caused by human immunodeficiency viruses (H I V) that undermine the immune system by infecting and destroying helper T cells, which stimulate both the cell-mediated and humoral immune responses