Bio314-lymphatic and immune system

the body harbors at least _____ times as many bacterial cells as human cells

10

define immune system:

not an organ system, but a cell population that inhibits all organs and defends the body from agents of disease

characteristics of the lymphatic system (4):

• network of organs and vein-like vessels that recover fluid

• insect it for disease agents

• active immune response

• return fluid to the bloodstream

describe fluid recovery of the lymphatic system:

fluid continually filters from the blood capillaries into the tissue spaces

blood capillaries reabsorb ____% in fluid recovery

85%

____% of the water and about half of the plasma proteins enter the lymphatic system and then are returned to the blood

15%

describe immunity (3):

• excess filtered fluid picks up forge in cells and chemicals from the tissues

• passes through lymph nodes where immune cells stand guard against foreign matter

• activates a protective immune response

describe lymph (3):

• clear, colorless fluid, similar to plasma, but much less protein

• originates as extracellular fluid drawn into lymphatic capillaries

• chemical composition varies in different places (intestines, after lymph nodes)

what are the lymphatic vessels?

transport the lymph

what is the lymphatic tissue?

composed of aggregates of lymphocytes and macrophages that populate (imbedded in) many organs in the body

describe lymphatic organs (2):

• defense cells are especially dense in these organs

• separated from surrounding organs by connective tissue capsules

what are 2 examples of lymphatic organs?

tonsils and spleen

describe the characteristics of lymphatic capillaries (5):

• penetrate nearly every tissue of the body

• capillary wall in endothelial cells overlapping each other like roof shingles

• closed at one end

• cells tethered to surrounding tissue by protein filaments

• endothelium creates valve-like flaps that open when interstitial fluid pressure is high, and close when it is low

valve-like flaps ___ when interstitial fluid pressure is high, and _____ when it is low

open, close

where are lymphatic capillaries absent?

• cartilage

• cornea

• bone

• bone marrow

gaps between cells are large enough to allow _____ and _____ to enter lymphatic capillary

bacteria and cells

larger lymphatic vessels are composed of… (3)

• tunica interna

• tunica media

• tunica externa

what are included in tunica interna?

endothelium and valves

what are included in tunica media?

elastic fibers and smooth muscle

what is tunica externa?

thin outer layer

T or F: lymphatic vessels converge into larger and larger vessels by collecting vessels course through many lymph nodes

True

what 6 lymphatic trunks drain major portions of the body?

• jugular, subclavian

• bronchomediastinal

• intercostal

• intestinal (unpaired)

• lumbar trunks

what are the 2 collecting ducts in the body?

• right lymphatic duct

• thoracic duct

describe the right lymphatic duct:

receive lymph from the right arm, right side of head, and throat; empties into the right subclavian vein

describe the thoracic duct (3)

• larger and longer

• begins as a prominent sac in abdomen called the cistern chyli

• receives lymph from below diaphragm, left arm, left side of the head, neck, and throat; empties into left subclavian vein

describe some basic characteristics of lymph flow (3):

• lymph flows under forces similar to those that govern venous heart return (except no pumping like the heart)

• lymph flows at low pressure and slower speed then venous blood

• moved along by rhythmic contractions of lymphatic vessels

• stretching of vessels stimulate contraction

describe the specifics of lump flow (6):

• flow aided by skeletal muscle pump

• arterial pulsation rhythmically squeezes lymphatic vessels

• thoracic pump aids flow from abdominal to thoracic cavity

• rapidly flowing blood in subclavian veins, draws lymph into it

• exercise significantly increase lymphatic return

what are natural killer (NK) cells?

larges lymphocytes that attack and destroy bacteria, transplanted tissue, host cells infected with viruses or that have turned cancerous

where do T lymphocytes mature?

in the thymus

what is the function of T lymphocytes?

fight off viral infections

what does the b stand for in “B lymphocytes (B cells)”?

bursa (bone)

where do B lymphocytes mature?

Bursa (bone)

what is the function of B lymphocytes?

fight bacteria infections

activation of B lymphocytes causes:

activation causes proliferation and diffraction into plasma cells that produce antibodies

what are macrophages?

large, avidly phagocytic cells of connective tissue

macrophages develop from _______

monocytes

functions of macrophages (2):

• phagocytize tissue debris, dead neutrophils, bacteria, and other foreign matter

• process and transport foreign matter and display antogentoc fragments to certain T cells alerting immune system to the presence of the enemy (antigen presenting cells-APCs)

describe dendritic cells

True

what are the functions of dendrite cells?

alert immune system to pathogens that have breached the body surface (mobile APC)

where are dendrite cells found? (3)

• epidermis

• mucous membrane

• lymphatic organs

define reticular cells:

branched stationary cells that contribute to the storm of a lymphatic organ

what is stroma?

framework of an organ

define lymphatic (lymphoid) tissue:

aggregations of lymphocytes in the connective tissues of mucous membranes and various organs

diffuse lymphatic tissue is the _______ form

simplest

are lymphocytes clustered or scattered in diffuse lymphatic tissue?

scattered

where is diffuse lymphatic tissue found?

body passages open to the exterior

• respiratory tract

• digestive tract

• urinary tract

• reproductive tract

• mucosa-associated lymphatic tissue (MALT)

what are lymphatic nodules ALWAYS found? (3)

• lymph nodes

• tonsils

• appendix

where are aggregated (clusters) of lymphoid nodules found?

ileum (distal portion of the small intestine)

T or F: lymphatic organs are NOT anatomically well-defined

false, lymphatic organs have connective tissue capsules that separated lymphatic tissue form neighboring tissues

define immunocompetent:

able to recognize and respond to antigens (“mature”)

where do T cells become immunocompetent?

thymus

where do B cells become immunocompetent?

red bone marrow

T or F: ALL lymphocytes are made in the red bone marrow

true

what are the 3 secondary lymphatic organs?

• lymph nodes

• tonsils

• spleen

secondary lymphatic organs are populated with _________ _________

immunocompetent cells

______ _______ ______ is involves in hemopoiesis and immunity

red bone marrow

describe characteristics or red bone marrow (3):

• soft, loosely organized, highly vascular material

• separated from osseous tissue by endosperm of bone

• as blood cells mature, they push their way through the reticular and endothelial cells to enter the sinus and flow away in the bloodstream

the thymus is a member of what systems? (3)

• endocrine system

• lymphatic system

• immune system

where is the thymus located?

directly superior to the heart

define the thymus:

bilobed organ located in superior mediastinum between the sternum and the aortic arch that secretes hormones and develops T cells

what does the thymus secrete?

hormones that regulate their activity

describe the degeneration of the thymus:

• thymus decreases in size as we get older

• lose the ability to produce new T-lympocytes for new antigens you have never been exposed to before

why did many elderly die from covid-19?

due to thymus degeneration

what divides the thymus unto several lobes?

fibrous capsule that gives off trabeculae (septa)

each thymus lobe contains:

T-lymphocytes

define thymus barrier:

epithelial cells seal off cortex from medulla forming blood

the thymus barrier produces signaling molecules called (5):

• thymosin

• thymopoietin

• thymulin

• interleukins

• interferon

T or F: lymph nodes are lease numerous lymphatic organ

False, they are the most numerous lymphatic organ

there are about ______ lymph nodes in a typical young adult

450

what are the 2 functions of the lymph nodes?

• cleanse the lymph

• act as a site of T and B cell activation

describe the structure of lymph nodes (2):

• elongated, bean-shaped structure with hilum

• enclosed with fibrous capsule with trabeculae that divides interior into compartments (stroma of reticular fibers and reticular)

lymph node interior is divided into ____ and ______

cortex and medulla

several _______ lymphatic vessels lead INTO the node along its convex surface

afferent

lymph leaves the node through one to three _______ lymphatic vessels that LEAVE the hilum

efferent

afferent and efferent vessels allow _______ ________

rapid movement

are there more afferent or efferent lymphatic vessels? why?

afferent, because it allows the pressure to buildup and therefore filtering the fluid

define metastasis:

cancerous cells break free from original , travel to other sites in the body, and establish new tumors

describe how metastatic cancer spreads through lymph nodes (3):

• metastasizing cells can easily enter the lymphatic vessels

• tend to lodge in the first lymph node they encounter

• they then, multiply there and eventually destroy the lymph node (swollen, firm, and usually painless)

• tend to spread to the next node downstream

what are the 3 treatments of breast cancer?

• lumpectomy

• mastectomy

• removal of axillary nodes

define what a mastectomy is:

removal of all breast tissue to prevent breast cancer

T or F: mastectomy has the same recurrence rate as other treatment

True

define tonsils:

patches of lymphatic tissue located at the entrance of the pharynx

what are the functions of tonsils?

to guard against ingested or inhaled pathogens

describe the structure of tonsils:

covered with epithelium and mucus have deep pits: tonsillar crypts lined with lymphatic nodules

what are the 3 main sets of tonsils?

• palatine tonsils

• lingual tonsils

• pharyngeal tonsils (adenoids)

what are paladin tonsils located?

pairat posterior margin of oral cavity

where are lingual tonsils located?

pair at the root of the tongue

where is the pharyngeal tonsil (adenoid) located?

single tonsil on wall of nasopharynx

what tonsil is most superior?

pharyngeal tonsil (adenoid)

what tonsil is most often infected (tonsillitis, etc.)

palatine tonsils

define spleen:

the body’s largest lymphatic organ

where is the spleen located?

left of the bladder

what are two types of tissue in the spleen?

• red pulp

• white pulp

what is red pulp?

sinuses filled with erythrocytes

what is white pulp?

lymphocytes and macrophages surrounding small branches of splenic artery

T or F: spleen highly vascular and vulnerable to trauma and infection

True

a ruptured spleen requires a _______

splenectomy

splenectomy’s lead to… (2)

• susception of future infections

• premature death

T or F: if you no longer have a spleen, your iron from hemoglobin CANNOT by recycled

True, the patient will need many blood transfusions and dialysis

what are the functions of the spleen (5)?

• healthy red blood cells (RBCs) come and go

• for old, fragile RBCs, spleen is “erythrocyte graveyard”

• blood cell production in fetus (and very anemic adults)

• white pulp monitors blood for foreign antigens and keeps an army of monocytes fro release when needed

• stabilizes blood volume through plasma transfers to lymphatic system