Chapter 20: Lympthatic System Flashcards by roxy rios

The lymphatic system consists of 3 parts:

Network of lymphatic parts
Lymph- fluid in vessels
Lymph nodes- cleanse lymph

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Lymphatic system:

Returns excess fluid that leaked from blood vessels back to blood.

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Lymphoid organs and tissues do what?

▪️provide structural basis of mine system
▪️house phagocytosis and lymphocytes
▪️structures include spleen, thymus, tonsils, lymph nodes, other lymphoid tissue

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Lymphatic vessels:

▪️return interstitial fluid and leaked plasma proteins back into blood
▪️~ 3 L /day
▪️once interstitial fluid enters lymphatics, called lymph

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Lymphatic vessels: distribution and structure:

▪️one- way system; flows toward heart
▪️lymphatic vessels include:
-Lymphatic capillaries
-Collecting lymphatic vessels
-Lymphatic trunks and ducts

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Lymphatic capillaries:

Similar to blood capillaries EXCEPT:
▪️very permeable (take up proteins, cell debris, pathogens, and cancer cells)
- endothelial cells overlap loosely to form one-way mini valves
▪️pathogens travel throughout body via lymphatics

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Lymphatic capillaries are absent from what?

Bones, teeth, bone marrow, and CNS

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Lacteals:

Specialized lymph capillaries present in intestinal mucosa

-absorb digested fat and deliver fatty lymph (chyle) to the blood

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Lymphatic collecting vessels:

Similar to veins EXCEPT:
Have thinner walls, with more internal valves
-anastomose more frequently
▪️collecting vessels in skin travel with superficial veins
▪️deep vessels travel with arteries
▪️nitrients supplied from branching vasa vasorum

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Lymphatic trunks:

◾️paired lumbar 
◾️paired bronchomediastinal
◾️paired subclavian
◾️paired jugular trunks 
◾️single intestinal trunk

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Lymphatic ducts:

Lymph delivers into one of two large ducts:
Right lymphatic duct drains right upper arm and right side of thorax

Thoracic duct arises as cisterna chyli ; drains rest of body

Each empires lymph into venous circulation at junction of internal jugular and subclavian veins on its own side of body

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Lymph transport:

Lymph propelled by :
▪️milking action of skeletal muscle
▪️pressure changes in thorax during breathing
▪️valves to prevent backflow
▪️pulsation of nearby arteries
▪️contractions of smooth muscle in walls of lymphatics

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Lymphocytes:

Main warriors of immune system

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Where do lymphocytes arise from?

Red bone marrow

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Lymphocytes mature into with two varieties ?

T cells( T lymphocytes )
B cells (B lymphocytes )

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Specific immunity involves which cells?

T cells
B cells
Neutrophils

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T and B cells protect against what?

Antigens !

Bacteria, bacterial toxins, viruses , cancer cells

T cells:

▪️manage immune response

▪️attack and destroy infected cells

B cells:

produce plasma cells which secrete antibodies

- antibodies mark antigens for destruction by phagocytosis or other means

Do T or B cells product antibodies?

B cells produce antibodies

Macrophages:

Phagocytize foreign substances, help activate T cells

Dendritic cells:

Capture antigens and deliver them to lymph nodes; activate T cells (antigen presenting cells)

Reticular cells:

Produce reticular fiber

Stroma:

Supports other cells in lymphoid organs

Lymphoid tissue:

Houses, provides proliferation site for, lymphocytes

Lymphoid is largely what kind of tissue?

Reticular connective tissue (loose connective tissue )

Two main types of lymphoid tissue:

Diffuse lymphoid tissue | Lymphoid follicles

Where are Peyers Patches located ?

Small intestine

Lymph nodes:

▪️principal lymphoid organs of body ▪️embedded on connective tissue in clusters along lymphatic vessels ▪️near body surface in inguinal, axillary, cervical regions of body

What are the 2 functions of lymph nodes?

1. Filter lymph - macrophages destroy microorganisms and debris 2. Immune system activation - lymphocytes activated and mount attack against antigens

Circulation in the lymph node:

Enters convex side via agreement lymphatic vessels; travel through large sub capsular sinus and smaller sinuses to medullary sinuses ; exists concave side at Hilum via efferent vessels

Spleen:

▪️Largest lymphoid organ ▪️served by splenic artery and vein which entree and exit at the Hilum ▪️functions: -sit of lump cute proliferation andime surveillance and response -cleases boos of aged cells and platelets , macrophages, remove debris -

Which organ is responsible for breakdown products of RBC?

Spleen

White pulp:

Most lymphocytes on reticular fibers involved with immune functions

Red pulp:

In venous sinuses. Rich in RBC and macrophages for disposal of worn out RBC and blood borne pathogens -composed of splenic cords and sinusoids

Thymus:

Important functions early on life. ▪️increases in size and most active during childhood ▪️stops growing during adolescence then gradually atrophies ▪️still produces incompetent ces but slowly

Most thymus cells are lymphocytes: true or false?

True | - cortex constrains rapidly dividing lymphocytes and thymus corpuscles involved in regulatory T cell development

The thymus differs from other lymphoid organs in important ways:

▪️has no follicles because it lacks B cells | ▪️functions strictly in T lymphocyte maturation. Keeps isolated with blood thymus barrier

Stroma:

Provide environment in which T lymphocytes become immunocompetent

4 types of lymphoid tonsils?

Palatine Linguinal Pharyngeal Tubal

To solar crypts:

Trap and destroy bacteria and particulate matter | -allow immune cells to bu memory for pathogens