Chapter 43: the immune system

Immune system: innate system: internal defenses: What is the purpose of TLRs and list 3 characteristics

internal defense cells= WBCs purpose: WBCs have transmembrane proteins (TLR) that binds to certain molecules on a pathogens surface -TLR located: some within the outer membrane of WBCs or in membrane bound vescicles 1. pathogen recognition triggers the internal defense cells 2. TLRs are non specific and bind to the non-self cell surface molecules of common group pathogens 3. different kinds of WBCs have different TLRs

Immune system: innate system: internal defenses: antimicrobial peptides

***proteins that attack microbes or stop their reproduction by recognition of blood groups of pathogens (gram +/- or bacteria, fungi) -location before trigger: may already be in the tissue(constitutive) or produced by macrophages, epithelial cells, or infected cells how they kill infected cells: i.integrate membranes causing a hole and/or altering membrane function ii. integrate with intracellular molecules altering their function VERTEBRATE IMMUNE SYSTEMS: interferons: induce cells to produce antiviral substances

Immune system: innate system: internal defenses: inflammation

-mast WBCs in CT produces HISTAMINE(nitrogenous chem) -histamine increases blood vessel permeability which allow antimicrobial peptides to enter tissue -macrophages produce PROSTAGLANDINS which attract other phagocytic WBCs to come to injury site

Immune system: acquired immunity: lymphocytes: antigen receptors

-transmembrane protein B and T cells that recognize antigens (foreign molecules)

Immune system: innate system: internal defenses: natural killer cells

-type of lymphocyte produced by lymphoid stem cells -kill cancerous/infected cells by releasing chemicals i. does not cause lysis which spead cell contents ii. does not phagocytize iii. dead cells disposed via urine and feces -activated by CYTOKINES from infected body cells cytokine=proteins produced by immune cells or injured body cells that help recruit/activate lymphocytes and NK cells

Immune system: innate system: internal defenses: phagocytosis: What 2 kinds of WBCs perform phagocytosis and what is its purpose?

-vacuoles with pathogens bond to lysosomes containing toxic gasses and enzymes to destroy them 2 types of WBCs: 1. neutophils 2. macrophages(monocytes): i. roam through vascular/lymphatic systems or ii. wait in various tissues(lymphatic) and organs

Immune system: acquired immunity: lymphocytes

2 types of lymphocytes: 1. T-cells: mature in thymus i. helper T-cells: activate lymphocytes (both B and T) ii. cytotoxic T-cells: disable infected cells 2. B-cells: mature in bone marrow i. one type that secretes antibodie activated by: CYTOKINES from macrophages and ANTIGENS (foreign molecule like pollen/bact.) -very specific; different T or B cells for each type of pathogen

Immune system: Innate system: What is the difference between innate and acquired immunity?

Innate immunity: plants, invertebrates, vertebrates -1 degree defense: active immediately whether pathogen has been rediscovered or not -non specific, detects invaders by molecular recognition -fast 2 kinds: External innate defenses and Internal innate defenses Acquired immunity: only in jawed vertebrates -2 degree defense -specific, vast receptors that recognize specific molecule with specific pathogen -slower cell mediated response- cytoxic cells (lymphocytes) humoral response- anti bodies in fluid

Immune system: Define

a collection of biological structures (cells, tissues, organs) and processes within an organism that help protect against disease by removing pathogens and abnormal cells

Immune system:Pathogen: Define

a disease causing mirco organisms, viruses and fungi

Immune system: innate system: internal defenses:What is the purpose of internal defenses?

purpose: to fight pathogen after it's inside the body internal defenses: 1.phagocytic cells (macrophages, neutrophils) engulf and destroy pathogens 2.natural killer cells [only in vertebrates] 3.antimicrobial peptides 4.inflammatory response [only in vertebrates]

Immune system: innate system: external defenses: barrier defenses: What is the purpose of external defenses? Name three barrier defenses

purpose: try to prevent entry of pathogen barrier defenses: 1.skin/exoskeleton-physical barrier (epithelial tissue) -ex: nose hairs: trap microbes from entering nose via ciliated epithelia to form boogers 2.mucous membranes-produces mucus to trap microbials 3. secretions-"wash away" microbes via tears, saliva, mucus by antibacterial enzyme LYSOZYME -antibacterial due to acidity