The Immune & Lymphatic System, Ch.22Types of Defense

________________________: Innate defenses Present at birth and provide immediate protection 1st line of defense: skin and mucous membranes 2nd line of defense: internal defenses

________________________: Immunity ______________ ______________

Nonspecific Defense Mechanisms Physical barriers

Chemical barriers

Increase in body temperature

Production of antimicrobial proteins

Inflammatory response

First line: skin & mucous membranes

Physical and chemical barriers: Epidermis

Skin =barrier, & when sheds will remove microbes Invade adjacent tissues & circulation thru cuts

Mucus- traps microbes Hair, cilia Lacrimal apparatus- tears contain lysozyme

Lysozyme found in: tears, perspiration, nasal secretions, & tissue fluids

Urine, vaginal secretions, defecation, vomit Acidic: sebum, perspiration, gastric juice, vaginal

secretions

Second line: Internal defenses

Antimicrobial proteins: Interferons (IFN)- virus infected cells produce anti-

viral proteins, communicate to uninfected cells Complement system- enhance immune, cytolysis,

phagocytosis, inflammation Transferrins- inhibit bacterial growth

Natural Killer Cells & phagocytes Inflammation Fever:

↑ temp due to reset hypothalamic thermostat Intensifies IFN, microbes, speed up repair

Natural Killer Cells

NKC = 5-10% of lymphocytes in blood Spleen, lymph nodes, RBM Lack molecules to identify T & B cells Ability to kill variety of infected & tumor cells Attack cell w/abnormal MHC

Bind Release granules of toxic substance

• Perforin cytolysis• Granzymes induce apoptosis or self-destruction

Kills cell but NOT MICROBES inside cell• Microbes need to be phagocytized

Phagocytes

Phagocytosis (part of Specific Immunity): Neutrophils __________________ wandering macrophages

Fixed macrophages stay put• Histiocytes, Kupffer cells, alveolar, microglia, and tissue

macrophages in spleen, lymph nodes, & RBM 5 phases:

_________________ Adherence Ingestion Digestion Killing

Inflammatory response fig 22.10 Causes: pathogens (bacteria, virus), abrasions,

chemical irritations, disturbances of cells, extreme temperatures, burns, radiation

4 signs & symptoms: ______________ ______________ ______________ ______________

Can also cause loss of function depending upon site and extent of injury:

Inflammatory response (2)

Purpose: attempt to dispose of microbes, toxins, foreign substances

Prevents spread of abovePrepare for repair and restoration3 Stages of inflammation:

Vasodilation & ↑ bv permeability Emigration of phagocytes Tissue repair

Vasodilation & ↑ permeability

Vasodilation ↑ blood flow to area Remove microbial toxins, dead cells

↑ permeability proteins & clotting factorsSubstances responsible:

Histamine Kinins Prostaglandins Leukotrienes Complement

1. When a localized area exhibits increased capillary filtration and swelling, this is an indication that

A. an immune response is underwayB. fever is developingC. inflammation is occurringD. Ab are phagocytizing target cellsE. fever is ending

2. Which type of molecule is produced by viral-infected cells to communicate to non-infected cells of the presence of a virus?A. ComplementB. InterferonC. PyrogenD. AntigenE. Antibodies

3. Saliva and tears contain this enzyme that destroys bacteria.A. TrypsinB. AmylaseC. LysozymeD. SalivaseE. Kinase

Specific resistance: ImmunitySpecificity and memoryHumoral or antibody-mediated (AMI)

_________________ into plasma cells synthesize & ___________ or immunoglobulins

Antibody bind and inactivates its antigen

Cell- mediated (CMI) _______________ proliferate into cytotoxic T

cells that ______________ the invading antigen

T cell populations

Cytotoxic T cells: Kill infected cells and cancer cells

Helper T cells: Secrete __________________- help regulate B cells

and T cells, play a pivotal role in BOTH humoral & cell mediated responses

Secrete protein factors and molecules secreted to regulate neighboring cells

Memory T cells: Remain from proliferated clone after CM response

Cell mediated immunity

Activation of T cells by specific antigen T cell proliferation & differentiation into clone of

effector cells Elimination – ________________ cytolysis Specific to specific antigens Can leave lymph tissue to seek and destroy

foreign antigens

Antibody-mediated response_______________________

________ responds to _____________ antigenStay in lymph tissue: nodes,spleen,MALT

Activated upon presence of foreign antigen Differentiate into plasma cells Produce antibodies

Ab circulate in lymph and blood to reach invasion site Some B cells become ____________________

Ab-mediated response

Inactive B cell receptor binds antigen, can stimulate T cell to intensify response

Plasma cells develop and produce Ab

Memory cells develop and remain to respond to antigen in the future

Production of antibodies

4. A "foreign" molecule which can invoke the immune response is called a(n)

A. AntigenB. ImmunoglobulinC. HaptenD. AntibodyE. Histamine

5. The immune cell that allows for subsequent recognition of an antigen resulting in a secondary response is called a(n)A. helper T-cellB. memory cellC. antigen-presenting cellD. plasma cellE. macrophage

6. Active, artificially acquired immunity is a result ofA. VaccinationB. Ab passed from mother to fetus

through the placentaC. Ab passed from mother to baby

through breast milkD. injection of immune serumE. Ab produced due to previous exposure

to an antigen

Clinical ConnectionsOrgan transplants- rejection dependent

upon similarity of MHCsImmunodeficiency- as in HIV, lose helper

T cells, opportunistic infections may occurAutoimmune diseases- fail to display self

tolerance and attack own tissuesHypersensitivity- allergic rxn to things that

most people tolerate (4 types)

7. Cytotoxic T cells kill target cellsA. through insertion of perforins into the

target's membraneB. by secreting antibodiesC. by phagocytosisD. through injection of tumor necrosis

factorE. Causing an inflammatory response

8. Lymphocytes that develop immunocompetence in the thymus areA. neutrophilsB. T lymphocytesC. B lymphocytesD. BasophilsE. Eosinophils

9. This type of disease results from the inability of the immune system to distinguish self from non-self antigens:

A. AllergyB. ImmunodeficiencyC. AnaphylaxisD. Autoimmune diseaseE. Inflammatory response

The Lymphatic System

Vessels Primary lymphatic organs

Red bone marrow Thymus

Secondary lymph organs and tissue Lymph nodes Spleen Lymph nodules (tissue because lacks capsule)

Functions of the Lymphatic System

Draining excess interstitial fluid ______________ = interstitial fluid that has

passed into a lymph vesselTransporting dietary lipids

Lacteals-- GI tract to bloodProtecting against invasion through

immune responses Lymphatic tissue = specialized reticular CT with

many lymphocytes

Lymphatic vessels, fig 22.2

Lymphatic vessels

Begin as lymph capillaries Spaces between cells, closed one end Unite to form larger vessels

Lymph vessels resemble veins but Are thinner Have more valves

Intervals along vessels: lymph nodes w/masses of T cells & B cells

Lymphatic vessels (2)

In skin: lie in subQ, follow same general route as veins

Viscera: generally follow arteries forming plexuses around them

Avascular tissue: often lack lymphatic capillaries Cartilage, epidermis, cornea, CNS, spleen,

RBM

Lymph capillaries

Slightly larger than blood capillarieshave a unique structure: interstitial fluid

can flow in but not outendothelial cells in wall overlap BUT:

when pressure is greater in interstitial fluid than in lymph, cells separate slightly

one-way valve opening, fluid enters when pressure greater capillary, closed & lymph

cannot flow out

Lymph capillaries (2)

Anchoring filaments- contain elastic fibers, attach lymphatic endothelial cells to surrounding tissues When excess interstitial fluid accumulates,

tissue swells filaments are pulled, opening larger for fluid to enter

Lacteals- specialized lymph capillaries in small intestine Carry dietary lipids lymph vesselsblood

Chlye- lipids present in lymph

Lymph formation and flow

Most components of plasma can filter freely to form interstitial fluid More out than back in lymph returns this fluid

Excess filtered fluid≈ 3L/day=lymph Small amt of proteins (most plasma proteins too large)

Proteins don’t easily diffuse backlymph important

Valves for one way movement Skeletal and respiratory pumps (as veins)

Lymph nodes

≈ 600 scattered throughout body superficial and deep, usually in groups however, high concentration in

Mammary gland Axillae Groin

Function as filters Foreign substances trapped by reticular fibers within

sinuses Macrophages destroy by phagocytosis Lymphocytes destroy by immune responses

Flow thru nodes is unidirectional

Afferent lymphatic vessels valves of node subcapsular sinus trabecular sinuses (cortex) medullary sinuses one of 2 efferent lymph vessels valves hilum = also where bv enter and leave

Primary (1°) lymphatic organs

Where stem cells divide & become immunocompetent

Red Bone MarrowThymusStem cells divide & mature into

B cells – red bone marrow T cells - thymus

2° Lymphatic organs and tissue

Where most immune responses occur Lymph nodes Spleen Lymphatic nodules

MALT – mucosa associated lymphatic tissue in mucous membrane: GI, urinary, repro tracts and respiratory airways

• GALT- gut associated lymphoid tissue Tonsils Peyer’s patches

Spleen is a lymphatic organ, fig 22.7

Largest single mass of lymphatic tissue In fetus develops blood cells Phagocytosis of worn out blood cells 2 types of tissue:

white pulp- mostly lymphatic tissueMacrophages & lymphocytes arranged around

branches of splenic artery red pulp – consists of venous sinuses filled with blood &

cords of splenic tissue RBC, macrophages, lymphocytes, plasma cells,

& granulocytes

Functions of the red pulp of spleen

______________ by macrophages of ruptured, worn out, or defective red blood cells and platelets

_______________________ (up to 1/3 of body’s supply)

_____________________ during fetal life