week 11

Lymphatic System

            One way system

            Made of

                        Lymph

                        Lymph vessels

                        Lymph nodes

                        Tonsils

                        Thymus

                        Bone marrow

                        Spleen

                        Appendix

                        Peyer's patches (or aggregated lymphoid nodules)

            Functions

                        Produces lymphocytes

                        Filters lymph

                        Absorbs fats into lymph vessels

                        Alternate route for return of tissue fluids

                        Assists with Immune system

                               

Lymph Capillaries

            Begin blind essentially

            Not continuous with anything

            Has no pump

                        Skeletal muscles, valves & respiration act as an indirect pump

            Small vast network

            Thin walled

            Valved

2 major lymph vessels

            thoracic duct

            right lymphatic duct

Thoracic duct

            Abdominal region

            Cisterna chili

                        is a dilated sac at the lower end of the thoracic duct into which lymph from the intestinal trunk and two lumbar lymphatic trunks flow

            goes through the diaphragm

            left side of the vertebrae

            empties into subclavian vein just before it ends

            drainage system for left half of head neck left arm and lower extremities

Right Lymphatic duct

            Smaller

            Drains right half of head and neck and right arm only

Lymph Nodes

            Made of lymphatic tissues

            Encapsulated

            Scattered along vessels

            Afferent vessels enter nodes & more numerous

            Efferent vessels leave node & less numerous

            Lymph moves slowly through node to give it time to be filtered

            Part of RES (reticuloendothelial system)

           

Appendix

            Experimentally verified as being rich in infection-fighting lymphoid cells, suggesting that it might play a role in the immune system

Tonsils

            Pharyngeal (adenoids)

                        Incompletely encapsulated

                        Located  on Roof of pharynx

            Palatine

                        Incompletely encapsulated

                        Sides of oropharynx between palatoglossal and palatopharyngeal arches

            Lingual

                        Incompletely encapsulated

                        Behind tongue

           

            Produce Lymphocytes

            Infections of tonsils can lead to breathing problems and hearing loss

Peyer’s Patches

            Collections of Lymphatic Tissue

            In Ileum of instesting

Thymus

            In mediastynum superiorly

            Bi lobbed

            Max development occurs in puberty

            Starts to degenerate after puberty

            Produces T-Cell Lymphocytes (critical cells of the adaptive immune system)

            2 hormones

                        Thymosin

                        Thymopoesin

Spleen

            12 cm long

            under diaphragm

            slit like opening à hylus for the artery, veins & nerves entering

            Made of red and white pulp

                        White pulp = typical lymphatic tissue

                        Red pulp = venous sinuses & cord of splenic cells

            Purposed with filtering blood

Digestive system to follow