A&PII Exam 2

The lymphatic system

a series of vessels that directs lymphatic fluid one way, up to the heart, to put the fluid back into circulation

The lymphatic system takes

extra interstitial fluid (fluid between tissues) and brings it back to the heart to enter back into blood circulation

The lymphatic system also has

valves

The lymphatic system picks up

Lymph from the tissues

85% of fluid from capillaries goes back into

blood circulation

15% of fluid stays in

interstitial fluid which enters into lymphatic system

Roles of the lymphatic system

maintain fluid levels in the body, absorb fat from the digestive tract, protects the body from foreign invaders (bacteria, viruses, etc), transports and removes waste products and abnormal cells

Lymph (lymphatic fluid)

fluid in the lymphatic system, made of interstitial fluid plus other components

Lymphatic vessels

network of vessels that moves lymphatic fluid back towards heart

Collecting ducts

area where lymph is dumped to enter back into circulation

Primary lymphatic organs

bone marrow and thymus

Bone marrow

where WBCs, RBCs, and platelets are produced

Thymus

where T lymphocytes are trained and mature

Secondary lymphatic organs

Lymph nodes and spleen

Lymph nodes

monitor and filter lymph, contain many lymphocytes

Spleen

Largest lymphatic organ, filters blood, produces WBCs

Lymph nodes are connected by

lymph vessels

Other lymphoid tissue line

organs to create a layer of protection

Other lymphoid tissue

tonsils and adenoids, Peyer’s patches (line small intestine), and appendix

Lymphatic drainage

1. Right lymphatic duct

2. Thoracic duct

Right lymphatic duct empties into

right subclavian vein, uses skeletal and respiratory pump

Thoracic duct

empties into left subclavian vein

Palatine tonsil

Visible tonsil

Pharyngeal tonsil

adenoids when enlarged

Lymph nodes are

Natural Killer cells when mature

Spleen contains large number of

macrophages that eat worn out RBCs, stores platelets, produces of blood cells during fetal life

The immune system

the defense system of the body, against pathogens

Pathogens

Foreign substances or antigens

The immune system must be able to distinguish between

self and non-self proteins

Most body cells have surface proteins called

major histocompatibility complexes (MHC)

Innate immunity

“inborn” present from birth, non-specific, rapid response

Innate immunity includes the

skin, mucous membrane, natural killer cells, phagocytes (neutrophils and macrophages), mast cells, dendritic cells

Adaptive immunity

acquired or programmed immunity, specific immunity

Adaptive immunity contains

B cells, T cells, memory cells, Dendritic cells, macrophages, and NK cells

Innate immune system deals with

inflammation, fever, and antimicrobial proteins

Adaptive immune system deals with

antibody production, antibody/antigen interaction, antibody mediated immunity- B cells, and cell-mediated immunity- T cells

First line of defense in innate immunity

Skin and Mucous membranes

Skin

Keratinocytes, a natural physical barrier

Skin is continuously

remaking and sloughing off

Sweat glands

produce sweat, provides skin surface with acidic pH to prevent bacterial growth

Dendritic cells (Langerhans cells)

First line of defense if something breaches the cell

Mucous membranes are in the

respiratory tract, nasal passages, and gastrointestinal tract

Mucous can trap

particles

Tiny hairs “cilia”

pushes mucous to different areas

Urine is

acidic

Urine keeps

bacterial growth low

Stomach

acidic gastric juices

Eyes

tears

Mouth

Saliva

Second line of defense

internal defense (NKCs)

Natural Killer Cells are found in

spleen, lymph nodes, and red bone marrow

Natural killer cells can attack

body cells that display abnormal or unusual plasma membrane proteins and release toxic granules

Monocytes can differentiate into

macrophages or dendritic cells

Monocytes are concentrated in

lymphoid organs and in body regions in direct contact with the environment

Phagocytes

ingest things (neutrophils and macrophages)

Phagocytes can be

wandering or fixed

Chemotaxis

chemical attraction of phagocytes to a site of damage

Adherence

Attachment of phagocytes to the microbe or other foreign material

Ingestion

Engulfing of the microbe

Digestion

joins with lysosome and forms phagolysosome

Phagocytosis steps

Chemotaxis, Adherence, Ingestion, Digestion, and Killing

Inflammation

innate response to tissue damage

Four characteristics of inflammation

redness, heat, swelling, and pain

Inflammation is an

attempt to dispose of foreign material from entering the body

Inflammation steps

1. Vasodilation and increased permeability of local blood vessels (WBCs and platelets release histamine)

2. Emigration of phagocytes

3. Chemotaxis and microbial attack

Histamine increase

blood vessel permeability “leaky”

Prostaglandins released to

intensify effects of histamines and stimulates more emigration of phagocytes

Leukotriens released to increase

capillary permeability and attracts more phagocytes

Fever

elevation of temperature either locally or systemically (elevated temp, elevates metabolism, elevated efficiency of cells, specifically immune cells) and inhibits growth of microbes

Antimicrobial proteins

Discourage microbial growth

Antimicrobial proteins are found in

various fluids of the body

interferons are produced by

cells of the body that have been infected with virus to interfere with the viral replication in healthy cells

Intereferons are found in the

blood plasma

Interferons are

normally inactive but when activated, complement or enhance certain immune reactions

Adaptive immunity is specific because

response is aimed at a particular non-self antigen

Antigens

substances that are recognized as foreign and produces an immune response

Basic training

Recognize the difference between self and non-self antigens

Self tolerance

ability of the cells to learn to recognize self antigens and avoid attacking them

Autoimmune disease

caused by a loss of self tolerance

Cell mediated immunity

cytotoxic T cells attack cells displaying foreign antigens

Antibody-mediated immunity

B cells recognize antigens, become activated into plasma cells and make antibodies

Memory cells

process takes a while but second response is much quicker

Major Histocompatibility Complex (MHC)

Bind self and non-self proteins and display on cell surface

MHC I

Display antigens that are internally produced endogenous antigens

MHC I are found on the surface of

all body cells except RBCs because they don’t have a nucleus

MHC II can display as

MHC I or MHC II

MHC II is found in

immune cells capable of phagocytosis

Antigen Presenting Cells

when cells are capable of phagocytosis, the proteins they bring in are exogenous (from outside the cell)

Cell-mediated immunity

1. starts with a cell with MHC I displaying non-self protein

2. Cytotoxic T cells recognizes the non-self proteins an attaches to the cell

3. Cytotoxic T cells is now activated and divides to produce clones (divides into T cells and memory cytotoxic T cells)

4. Activated cytotoxic T cells attach MHC I cells which causes cells to undergo apoptosis (cell death)

Antibody mediated immunity is either activated by

free floating antigen or T helper cell

Antibody mediated immunity activated by free floating antigen

1. B cell has B cell receptors that contacts free floating antigen binds and activates B cell

2. B cell goes through clonal expansion (makes memory B cells and activated B cells)

3. Activated B cells start pumping out antibodies which is the exact same as the receptor

4. Binds and stops antigens or flags other cells to kill antigen

MHC II activates

T cells

Activated T helper cell goes to

bind a B cell to activate it or cytotoxic T cell

Antigens provoke

an immune response through stimulating the immune system to produce antibodies (viruses, bacteria)

Antibodies

proteins that can help immune cells destroy antigens

Antibodies are

immunoglobins

Antibodies are composed of

heavy and light chains

Constant region of antibodies

The majority, the same in all antibodies, part that is interested into the cell

Variable region of antibodies

Varies, antigen binding area

Antigen/Antibody interaction

stops the antigen from infecting other cells