Lab Test #3 Physiology

What is the lymphatic system comprised of?

-specialized organs and tissues housing concentrated numbers of white blood cells (such as lymphocytes)

-a fluid called lymph

-lymphatic vessels

Which lymphocyte is involved in Antibody-Mediated Immunity

B-Lymphocytes

Which lymphocyte is involved in Cell-Mediated Immunity

T8-Lymphocytes

Which lymphocyte is involved in both CMI and AMI

T4-Lymphocyte

Which lymphocytes have receptors that bind to MHC 1 receptors on body cells

T8-Lymphocytes

Which lymphocytes have receptors that bind to MHC 2 receptors on Antigen Presenting Cells

T4-Lymphocytes

Antigen Presenting Cells

B cells, macrophages, dendritic cells

Which lymphatic organ is considered to be partially diffuse lymphatic tissue and forms a protective pharyngeal lymphoid ring

tonsils

What are the 3 functions of the lymphatic system?

draining excess fluid, carrying out immune responses, and absorption of dietary fats

the fluid portion of the lymphatic system flowing in lymphatic vessels

Lymph

What is lymph composed of?

-Interstitial fluid

-Dissolved solutes including leaked plasma proteins

-Large amounts of lipids absorbed from the small intestine

What is interstitial fluid?

fluid leaked from blood into tissues

Lymph drains from all lymphatic vessels into what?

-Right lymphatic duct

-Left lymphatic duct (thoracic duct)

Where does the right lymphatic duct receive lymph from?

the right arm and shoulder, the right upper chest, and the right side of the head

Where does the left lymphatic duct receive lymph from?

the left side of the head, the left upper chest, the left shoulder, the left arm, the abdomen, and the legs

The right and the left lymphatic ducts are connected to the _______________

junction of the jugular and subclavian veins

Junction of the jugular and subclavian veins

the site where lymph is drained back into blood circulation

What happens to the lymphatic vessels when the muscles contract?

they are squeezed, which propels the lymph forward through one way valves

The constant movement of lymph away from tissue helps prevent _______

edema (tissue swelling)

The return of fluid back into the blood maintains__________

proper blood volume, pressure and flow.

________ are constantly exposed to lymph as it flows through lymphatic organs, like lymph nodes

Lymphocytes, macrophages, and other immune system cells

If foreign antigens and pathogens are in the lymph, the immune system cells are ____________. Thus, the constant flow of lymph ____________

-stimulated to produce immune responses that destroy and eradicate the antigens and pathogens from our body

-protects us from harmful microbes and maintains normal blood circulation

Diffuse Lymphatic Tissues

mucous associated lymphatic tissue

MALT

mucous associated lymphatic tissue

What are diffuse lymphatic tissues (called Mucous Associated Lymphatic Tissue; MALT) composed of?

scattered lymphocytes in the connective tissue of mucous membranes lining the passageways of the respiratory, digestive, urinary, and reproductive systems

disease causing microbes

pathogens

-Concentrated clusters of lymphocytes and macrophages occur in structures called ___________.

-These follicles are commonly found in the ________

-lymphatic nodules or follicles

-tonsils, lymph nodes, small intestine (Peyer’s Patches), and the appendix

Name the primary lymphatic organs

Red Bone Marrow and the Thymus gland

are the sites where B & T lymphocytes are produced and mature into immunocompetent cells

primary lymphatic organs

immunocompetent cells

cells that have the ability to produce immune responses against specific invading pathogens and foreign antigens

Name the secondary lymphatic organs

lymph nodes, tonsils, and the spleen

are the sites where lymphocytes carry out the immune responses to rid the body of harmful microbes (Pathogens; disease causing agents

secondary lymphatic organs

Where is red bone marrow located?

in our bones where spongy bone is located (Epiphyses of long bones, in between the plates of flat bones (the cranial bones, the ilium, and the sternum), and in irregular shaped bones like the vertebrae)

Red bone marrow is the site where all ______ are produced including the ________

blood cells; lymphocytes

Where do B Lymphocytes mature into immunocompetent cells

Red bone marrow

Activated B lymphocytes that produce antibodies

Plasma Cells

AMI

antibody-mediated immunity

CMI

cell-mediated immunity

mature in red bone marrow then enter circulation to find their home in lymphatic tissues and organs around the body

B-lymphocytes (B-Cells)

When B-Lymphocytes are activated against particular antigens or pathogens, they develop into antibody producing cells called ________

plasma cells

secreted proteins that target specific antigens and pathogens to help destroy and eradicate them from the body (Antibody-Mediated Immunity; AMI)

Antibodies

What happens when B cell is activated?

they produce antibodies that can bind to pathogen= antibody mediated immunity (AMI)

Where does T-Lymphocytes (T-Cells) differentiate and mature into immunocompetent cells?

The Thymus Gland

-Immature T-cells (pre T-Cells) migrate from _______ to the _____.

-These pre T-Cells will differentiate into subpopulations of T-Cells called _______ (____________) and ______ (___________).

-red bone marrow; thymus

-CD8 cells (T8 Cells or Cytotoxic Killer T-Cells); CD4 cells; T4 Cells or Helper T-Cells).

________ fight off infectious agents via cell-to-cell combat and thus are involved in the ________

T8-Cells; Cell Mediated Immune Response (CMI)

T4-Cells help activate _______ and _________ to initiate ____ and ____ respectively

T8-Cells; B-Lymphocytes; CMI; AMI

T-cells are tested in the ______ as part of their maturation process

thymus

What happens when T-cells recognize and react to self antigens (antigens from a person’s own body)?

they fail the test and are destroyed

T-Cells that fail to react with self antigens pass the test and leave the _______ to enter ________ where they will find their home in ______________ (these T-Cells are immunocompetent and are ready to fight off infectious agents).

thymus; circulation; lymphatic tissues and organs like the lymph nodes

The inactivation and destruction of T-Cells that fail the tests in the thymus is a ________ in our body to prevent the development of __________ and to ____________ that we are exposed to throughout our life.

protective measure; autoimmune disorders; increase our immunity to an ever growing group of pathogenic microbes

-Where is the thymus gland located?

-What is it surrounded by?

-in the thoracic cavity anterior and superior to our heart and posterior to the sternum

-connective tissue capsule

Connective tissue fibers from the capsule (called ______) dive inward to separate the gland into ________

Trabeculae; Thymic Lobules

Thymic lobules have an ________ containing large numbers of __________, and an _________ containing _________

outer cortex; immature T-Cells; inner medulla; mature T-Cells

The mature T-Cells enter circulation from the _______ and find their way to the ___________

medulla; various lymphatic tissues around the body where immune responses occur

What is the largest lymphatic organ in the body? How long is it?

The spleen; 4.5 to 5 inches long and 3 inches wide

Where is the spleen located?

in the left hypochondriac region (located in the upper left quadrant of the abdominal cavity) just inferior to the diaphragm, lateral to the left kidney, and posterolateral to the stomach

__________ surrounds and protects the spleen

The lower part of the rib cage (Ribs 10 - 12)

What is the spleen encased in? What does it contain?

connective tissue capsule and contains tissue cells referred to as either Red Pulp or White Pulp

The _____ portion of the spleen takes on a curved smooth shape as it lines the left lateral body wall

lateral

The ______ portion of the spleen is concaved in which the left kidney and the stomach presses into it

medial

is the indented medial portion of the spleen where nerves, blood vessels, and lymphatic vessels penetrate it

The hilum

Blood is delivered to the spleen via what? What is it drained by?

the splenic artery and is drained by the splenic vein

The majority of the tissue in the spleen is comprised of ______

red pulp

What is red pulp composed of?

large numbers of erythrocytes and platelets with scattered lymphocytes housed in reticular connective tissue forming the splenic cords or Cords of Bilroth

Capillaries with ______ (_______) are scattered through the red pulp that allow blood cells to easily emigrate (leave circulation) to tissue

increased permeability (Splenic Sinusoids)

What do the sinusoids do?

join together and drain blood into the splenic vein

About _____ of the body’s platelets are stored in the ______ and can enter _______ during ________

30%; spleen; circulation; hemorrhaging events

What is white pulp composed of? What does it surround and what is it shaped like?

T-Lymphocytes, B– Lymphocytes, and Macrophages; surrounds a central artery and is shaped like a cylinder

What do red and white pulp together serve to monitor?

blood flow for foreign antigens

What are red and white pulp involved in?

-Phagocytosis of bacteria and old or defective RBC’s and Platelets

-Storing platelets

-Hemopoeisis (only in fetus) but may be activated in the adult during severe anemia

Lymph nodes are ____________ shaped like what?

secondary lymphatic organs; a kidney bean with an indented surface called the hilum

There is a _________ surrounding the lymph node with _______ partially compartmentalizing its interior

fibrous connective tissue capsule; trabecular extensions

the outer portion containing lymphatic nodules (oval shaped aggregates of B-Lymphocytes)

The cortex

extends from the middle of the node to the hilum

The medulla

What does the medulla contain?

branching medullary cords composed of reticular fibers around which lymphocytes, plasma cells, and macrophages can be found

Lymph nodes are positioned along the lengths of ________ throughout the body

lymphatic vessels

Lymph flows through what? And into…

several afferent lymphatic vessels into the convex surface of the lymph node and exists at the hilum through 2 efferent lymphatic vessels

Lymphocytes are continuously monitoring what? Immune responses are triggered when _________.

the flowing lymph for foreign antigens and infectious agents; lymphocytes are activated against specific pathogens

What lymph nodes are in the Neck Region?

Cervical lymph nodes

What lymph nodes are in the Armpit Region?

Axillary lymph nodes

What lymph nodes are in the Thoracic Region?

Thoracic lymph nodes

What lymph nodes are in the Abdominal Region?

Abdominal lymph nodes, Intestinal lymph nodes, Mesenteric lymph nodes, and Iliac lymph nodes

What lymph nodes are in the Groin Region?

Inguinal lymph nodes

-These lymphocytes are divided into 2 main groups based on the receptors they contain in their membrane and their function.

-What are these groups?

-T-Cells

-T8-Cells and T4-Cells

-These are cytotoxic killer T-Cells that contain CD8 receptors.

-What do they bind to?

-T8-Cells

-MHC (Major Histocompatibility) I receptors on all body cells except erythrocytes which do not contain MHC I

What do T8-Cells carry out?

Cell Mediated Immunity (CMI; “Cell-to-Cell combat”).

-These are helper T-Cells that contain CD4 receptors.

-What do they bind to?

-T4-Cells

-MHC II receptors on Antigen Presenting Cells (B-Cells, Macrophages, and Dendritic Cells)

T4-Cells help initiate

CMI & AMI

When these lymphocytes are activated they develop into plasma cells which secrete antibodies; Antibody Mediated Immunity (AMI)

B-Cells

What happens when B-Cells are activated?

they develop into plasma cells which secrete antibodies; Antibody Mediated Immunity (AMI)

Unlike blood capillaries, lymphatic capillaries are what?

closed ended and more permeable for fluid entry

What are lymphatic capillaries composed of?

an endothelial lining and a thin basement membrane

Lymph moves in what direction?

In an ever forward direction through the valves as skeletal muscle contract around them producing compression forces on the vessels

Lymph enters blood from the _______ at the junction of the _________

left and right lymphatic ducts; jugular and subclavian veins

Tonsils partially diffuse ________

secondary lymphatic tissues

The tonsils are covered apically by ________ and partially covered by a ____________ which separates them from the underlying tissue

mucosal epithelium; connective tissue capsule

Surface invaginations of the mucosal epithelium form deep crypts called _______

tonsillar crypts

line the tonsillar crypts and are the sites where specific immune responses may be initiated to eliminate pathogens

Aggregations of lymphatic nodules

These lymphatic nodules contain germinal centers which are the sites for what?

B-Cell maturation into antibody producing plasma cell

The single Pharyngeal Tonsil (Adenoid) is located in the _______

roof of the pharynx just posterior to the nasopharynx