Adjacent cells in lymphatic capillaries overlap each other loosely. These cells form a unique structural modification that increases their permeability that is known as the __________.

minivalves

Which of the following promotes closure of the minivalves associated with lymph capillaries?

increasing pressure inside the lymph capillary

To what organ do the lymphatic vessels return protein-rich escaped fluids to rejoin circulation?

heart

What do collecting lymphatic vessels NOT share in common with veins of the cardiovascular system?

thickness of the walls

What is the main function of the lymphatic system?

The lymphatic system returns leaked fluid and plasma proteins that escape from the bloodstream to the blood.

Which of the following lacks lymph capillaries?

bones and teeth

Lymph from the right leg ultimately is delivered to which duct in the thoracic region?

thoracic duct

Lymph from what regions of the body is drained into the right lymphatic duct?

right upper limb, right side of the head and thorax

What is the name of the enlarged sac to which the lumbar trunks and the intestinal trunk returns lymph?

cisterna chyli

Which of the following returns lymph to the right lymphatic duct?

right side of the head

Which of the following delivers lymph into the junction of the internal jugular vein and the subclavian vein?

thoracic duct

What type of tissue is commonly found in all lymphoid organs and tissues (except the thymus)?

reticular connective tissue

What is the role of the B lymphocytes (B cells) in lymphoid tissue?

produce plasma cells that secrete antibodies

What is the role of dendritic cells in lymphoid tissue?

capture antigens and bring them back to lymph nodes

Which of these lymphoid organs is the thymus? Select from letters A-D.

B

Which of these lymphoid organs destroys bacteria before it can breach the intestinal wall and generates "memory" lymphocytes for long-term memory? Select from letters A-D.

D

Which letter represents the tonsils? Select from letters A-D.

A

Where are the three large clusters of superficial lymph nodes?

cervical, inguinal, and axillary regions

The filtration of lymph and immune system activation are the two basic functions of the __________.

lymph nodes

Lymph nodes are surrounded by a capsule from which connective tissue strands extend inward to divide the node into compartments. What is the name of these strands?

trabeculae

What region of the lymph node contains densely packed follicles with dividing B cells?

cortex

Which lymphoid organ is primarily active during the early years of life? Select from letters A-D.

B

Which of these lymphoid organs is a part of collection of tissues called the mucosa-associated lymphoid tissues (MALT) and removes pathogens entering the pharynx (throat)? Select from letters A-D.

A

Which lymphoid organ extracts aged and defective blood cells and platelets from the blood in addition to storing some of the breakdown products for later reuse? Select from letters A-D.

C

Which part of the spleen is the site of immune function?

white pulp

Where are worn-out erythrocytes found in the spleen?

red pulp

Where is the spleen located?

left side of the abdominal cavity just beneath the diaphragm and curled around the anterior aspect of the stomach

Where is the lingual tonsil located?

base of the tongue

Tonsillar crypts are invaginations deep into the interior of the tonsil. What is missing from the tonsil that allows for the presence of tonsillar crypts?

capsule

Which tonsil is located in the posterior wall of the nasopharynx and is referred to as the adenoids if it is enlarged?

pharyngeal tonsil

What type of cell is the precursor to the helper T cell?

CD4 cell

What type of cell is a precursor to the cytotoxic T cell?

CD8 cell

What activates CD8 cells?

antigen fragments on class I MHC proteins

What type of T cell can directly attack and kill other cells, such as virus-infected cells?

cytotoxin T (TC) cells

Cytotoxic T (TC) cells check cells of the body for identity flags to see if they look they way they are supposed to. What is this process called?

immune surveillance

Which type of T cell will recognize antigens associated with an allograft?

cytotoxin T (TC) cell

Which letter represents the formation of a phagolysosome resulting from the fusion of a lysosome with the phagocytic vesicle? Select from letters A-D.

C

With what does our immune system coat pathogens to facilitate their capture and accelerate phagocytosis?

opsonins

Which letter represents the adhesion of the phagocyte to the pathogen? Select from letters A-D.

A

Four (or five) cardinal signs indicate inflammation. What specific sign of inflammation is the result of exudate in the tissue spaces?

edema (swelling)

Which of the following inflammatory chemicals is released by mast cells?

histamine

Which of the following is NOT one of the cardinal signs of inflammation?

vasoconstriction

When do neutrophils enter the blood from the red bone marrow, in response to leukocytosis-inducing factors?

leukocytosis

What is the main event of chemotaxis?

Neutrophils and other WBCs migrate up the gradient of chemotactic agents to the site of injury.

Neutrophils flatten and squeeze between the endothelial cells of the capillary walls during what process?

diapedesis

What protein can be released by infected cells to help protect cells that have not yet been infected?

interferons (IFNs)

How do interferons protect against infection in healthy cells?

Interferons block viral reproduction in healthy cells through the production of antiviral proteins.

What is the specific target of interferons?

nearby healthy cells

Which cells mature in the thymus?

T cells

How does a lymphocyte become immunocompetent?

Lymphocytes must be able to recognize their one specific antigen by binding to it.

What are B and T cells called that have not yet been exposed to an antigen?

naive

How would you classify the antivenom used to treat poisonous snake bites?

passive immunity, artificially acquired

Which of the following exemplifies passive immunity?

antitoxin

Which of the following best illustrates artificially acquired active humoral immunity?

vaccines

What part of the antibody's structure determines its class?

constant (C) region

Which immunoglobulin class can cross the placenta to provide naturally acquired passive immunity to the fetus?

IgG

What is the first antibody released in the primary response and usually indicates infection?

IgM

Which mechanism occurs when antibodies block specific sites on viruses or bacterial exotoxins?

neutralization

Which of the following mechanisms of antibody action occur when red blood cells clump due to a transfusion of mismatched blood?

agglutination

Which mechanism of antibody action results in cell lysis?

complement fixation and activation