BIO 206 Exam 3 Study Guide

BIO 206

Functions of the spleen include all of those below except

Forming crypts that trap bacteria

Cell-mediated (cellular) immunity is mediated by

T cells

Which of the following would not be classified as a \n lymphatic structure?

Liver

Antibody-mediated (humoral) immunity is mediated by

B cells

B lymphocytes develop immunocompetence in the

Bone marrow

The process whereby neutrophils and other white blood \n cells are attracted to an inflammatory site is called

Chemotaxis

The process whereby neutrophils and other white blood \n cells congregate along the inside of capillaries

Margination

Which of the following is a part of the first line of \n defense against microorganisms

Mucus

Innate immune system defenses include

Phagocytosis

The loss of which cell type due to HIV infection leads to \n acquired immunodeficiency syndrome:

T-helper cells

A person exposed to a new cold virus would not feel \n better for one to two weeks because

No memory cells can be called upon, so \n adequate response is slow

This is the lymphatic organ that is involved in removing \n old or defective cells from the blood, storing platelets, \n and serving as a surveillance site form lymphocytes

Spleen

These are the simplest lymphoid organs. They form a \n ring of lymphatic tissue around the pharynx. They \n contain crypts that trap and destroy bacteria and \n particulate matter

Tonsils

Which of the following is not a type of T cell?

Antigenic

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

Antigen

Vaccines generally confer what type of immunity?

Artificially acquired active immunity

What is the antigen challenge, and where does it usually \n take place?

The antigen challenge is the first encounter between an immunocompetent lymphocyte and an invading antigen. It usually takes \n place in the spleen or a lymph node, but may happen in any lymphoid tissue.

What is the most likely type of hypersensitivity \n associated with an agonizingly itchy case of poison ivy, \n appearance of hives after eating shellfish, or a positive \n TB test?

The hypersensitivity associated with poison ivy is an example of delayed hypersensitivity called allergic contact dermatitis. The \n hypersensitivity associated with hives is an immediate hypersensitivity in the form of a local anaphylactic reaction. The \n hypersensitivity associated with a positive TB test is a type of delayed hypersensitivity

The antibody that becomes bound to mast cells and \n basophils and causes the cells to release histamine and \n other chemicals is

IgE

Why are regulatory T cells important to the immune \n process?

They are vital in the final stopping of an immune response after the antigen is inactivated. They may also help prevent \n autoimmune reactions

What are the signs of inflammation, and how does \n inflammation serve as a protective function?

The four signs of inflammation are swelling, redness, heat, and pain. The signs are caused by local vasodilation and increased \n capillary permeability. This is of benefit because the process helps to dilute harmful substances that may be present; brings in \n large quantities of oxygen, nutrients, and cells necessary for the repair process; and allows the entry of clotting proteins. Pain \n helps immobilize the injury.

Why do schools require inoculations for childhood \n diseases such as mumps, measles, and whooping cough? \n Why are the inoculations of value?

The inoculations are required to try to prevent epidemics of these microbiological infections. The inoculations are of great \n benefit in preventing the diseases because the vaccines cause immunity to the pathogens by stimulating both the formation of \n protective antibodies and the establishment of immunological memory against future infection.

Three parts of the lymphatic system

Lymphatic vessel network, lymph. lymph nodes

What is the function of the lymphatic system?

Returns interstitial fluid and leaked plasma proteins \n back to the blood. Together with lymphoid organs and tissues, provide the structural basis of the immune system

Lymphatic vessels include:

Lymphatic capillaries, lymphatic collecting vessels, lymphatic trunks and ducts

In lymphatic capillaries…

Endothelial cells overlap to form one-way \n mini-valves, and are anchored by collagen \n filaments, preventing collapse of capillaries \n

Lacteals

specialized lymph capillaries present in \n intestinal mucosa; Absorb digested fat and deliver fatty lymph (chyle) to the blood

Lymphatic Collecting Vessels

Have thinner walls, with more internal valves; Collecting vessels in the skin travel with superficial veins; Deep vessels travel with arteries

Lymphatic Trunks

Formed by the union of the largest collecting ducts;

* Paired lumbar
* Paired bronchomediastinal
* Paired subclavian
* Paired jugular trunks
* A single intestinal trunk

\n

Lymphatic Duct

Lymph is delivered into one of two large ducts

* Right lymphatic duct drains the right upper arm \n and the right side of the head and thorax


* Thoracic duct arises from the cisterna chyli and \n drains the rest of the body

Each empties lymph into venous circulation at the \n junction of the internal jugular and subclavian veins \n on its own side of the body

Lymph Transport

Propelled by

* Pulsations of nearby arteries
* contractions of smooth muscle in the walls of the lymphatics

Lymphocyte varieties

* T cells


* B cells

\
Protect against antigens

\-Bacteria and their toxins \n - Viruses \n - Mismatched RBCs \n - Cancer cells \n \n

T cells

\-Manage the immune response \n - Attack and destroy foreign cells

B cells

\-Produce plasma cells, which secrete antibodies

Macrophages

phagocytize foreign substances \n and help activate T cells

Dendritic cells

capture antigens and deliver \n them to lymph nodes

Reticular cells

produce stroma that supports \n other cells in lymphoid organs

Lymphoid Tissue

\-Houses and provides a proliferation site for \n lymphocytes \n

\-Furnishes a surveillance vantage point

Two types of lymphoid tissue

\-Diffuse lymphatic tissue \n

\-Lymphatic follicles \n \n

Lymph Nodes

* Principal lymphoid organs of the body \n
* Embedded in connective tissue, in clusters \n along lymphatic vessels \n
* Near the body surface in inguinal, axillary, and \n cervical regions of the body \n \n

Lymph Node Functions

1. Filter lymph—macrophages destroy \n microorganisms and debris \n
2. Immune system—lymphocytes are activated \n and mount an attack against antigens

Structure of a Lymph Node

\-Bean Shaped

\-External fibrous capsule

\-Trabeculae extend inward and divide the node \n into compartments

\
__**REGIONS**__

* Cortex
* Medulla

Circulation in the lymph nodes

* Enters via lymphatic vessels
* Travels through large subscaplar sinus and smaller sinuses
* Exits the node at the hilus via efferent vessels

Largest lymphoid organ

Spleen

What is the function of the spleen?

* Site of lymphocyte proliferation and immune surveillance and response
* Cleanses the blood of aged cells and platelets and debris
* Stores breakdown products of RBCs for later reuse
* Stores blood platelets
* Site of fetal erythrocyte production (normally ceases after birth)
* Contains lymphocytes, macrophages, and huge numbers of erythrocytes

What is the structure of the spleen?

* White pulp around central arteries
* Red pulp in venous sinuses and splenic cords

How does the thymus differ in size due to age?

In infants, it is found in the inferior neck and extends into the mediastinum. It is large enough to partially overlie the heart. As infants age into childhood, it is most active, and increases in size. Later in adolescence, it stops growing, eventually atrophying.

What does the thymus contain?

* Outer cortex
* Densely packed lymphocytes and scattered macrophages
* Medulla
* Fewer lymphocytes and thymic corpuscles involved in regulatory T cell development

\

How does the thymus differ from other lymphoid organs?

* Functions strictly in T lymphocyte production
* Does not directly fight antigens

Simplest lymphoid organs

Tonsils

Palatine tonsils

At posterior end of the oral cavity

Lingual tonsils

Grouped at the base of the tongue

Phalangeal tonsils

In posterior wall of the nasopharynx

Tubal tonsils

Surrounding the openings of the auditory tubes into the pharynx

What do tonsils contain?

Follicles with germinal centers

What do cysts do in tonsils?

Trap and destroy bacteria and particulate matter

Peyer’s Patch

* Cluster of lymphoid follicles
* In the wall of the distal portion of the small intestine
* Similar structures also found in the appendix

\

What does MALT do?

Protects the digestive and respiratory systems from foreign matter

What is immunity?

Resistance to disease

What are the two intrinsic immune systems?

Innate and adaptive immunity

What are the innate immunity defenses?

1. Skin
2. Mucosae
3. Antimicrobial proteins
4. Phagocytes

* Inflammation is the most important mechanism

\

What are the adaptive immunity defense systems?

Attacks foreign substances, and takes longer than the innate immune system

Innate Defenses

* Surface Barriers
* Skin
* Mucous membranes
* Internal Defenses
* Phagocytes
* Natural killer cells
* Inflammation
* Antimicrobial proteins
* Fever

Adaptive Defenses

* Humoral immunity
* B Cells
* Cellular immunity
* T Cells

What do keratinocytes compose?

Make up the majority of cells in the epidermis

* Outermost layer of the epidermis is composed of dead keratinocytes

What are the functions of hair?

1. Altering the body to presence of insects on the skin


1. SGuarding the scalp against physical trauma, heat loss, and sunlight

Where is hair distributed on the body?

Entire surface except palms, soles, lips, nipples, and portions of the external genitalia

What cavities do mucous membranes line?

* Mouth
* Digestive tract
* Respiratory tract
* Urinary tract

Sebum

Forms a protective acidic film over the skin surface that is hostile to many bacteria

Perspiration, tears, saliva

Contains an enzyme called lysozyme, which is a natural antibacterial chemical

Gastric Acid

The extremely low pH of the acid kills many pathogens

Bacteria

Helps create a hostile environment for other microbes

What are phagocytes?

White blood cells that wander through tissues, engulfing and removing anything that does not belong there

What are the two types of phagocytes?

* Neutrophils
* First to leave the blood vessels in response to infection or cell damage “Bacteria slayers”
* Macrophages
* Large actively patrolling white blood cells that left the blood vessels
* Travel through every tissue looking for foreign material

Cardinal signs of acute inflammation

1. Redness
2. Heat
3. Swelling
4. Pain
5. Impairment of function

What is stage one of inflammatory response?

Vasodilation and increased vessel permeability

What is edema?

Increased plasma filtrate seeps into tissue spaces bringing some immune proteins

What is stage two of inflammatory response?

Phagocyte mobilization

Leukocytosis

Release of neutrophils from bone marrow \n in response to leukocytosis-inducing factors from \n injured cells

Margination

Neutrophils cling to the walls of capillaries \n in the inflamed area

Diapedesis

Neutrophils flatten and \n squeeze out of capillaries

Chemotaxis

Inflammatory chemicals (chemotactic \n agent) promote positive chemotaxis of neutrophils

What is stage three of inflammatory response?

Tissue repair

Interferon

\n Attacks virally infected cells

Interferon functions

* Anti-viral
* Reduce inflammation
* Activate macrophages and mobilize NK cells

\n complement system

series of chemical reactions brings together a group of \n proteins that are usually floating freely in the plasma

Fever

change in the body's temperature set point

pyrogens

proteins that reset the body's thermostat to \n a higher temperature

\n lymphocytes

series of white blood cells that recognize and remember pathogens

Antibody-mediated (or humoral) immunity

Specialized B-lymphocytes create disease-fighting compounds \n called antibodies

Cell-mediated (or cellular) immunity

* Specialized T-lymphocytes directly attack pathogen-containing cells
* Through direct cell-to-cell contact

Antigen

any substance \n which provokes specific \n immune responses

Antigenic determinants

Parts of antigens that \n trigger the specific \n immune response

TS cells

immune regulatory cells which release \n cytokines that suppress the activity of both T \n cells and B cells

IgD

monomer attached to the surface of B cells, important in \n B cell activation

IgM

pentamer released by plasma cells during the primary \n immune response

IgG

monomer that is the most abundant and diverse antibody \n in primary and secondary responses; crosses the placenta \n and confers passive immunity

IgA

dimer that helps prevent attachment of pathogens to \n mucosal surfaces

IgE

monomer that binds to mast cells and basophils, causing \n histamine release when activated

Neutralization

Antibodies block \n specific sites on viruses or bacterial \n exotoxins, thus preventing these \n antigens from binding to receptors on \n cells.