Lymphatic Ch 20 Flashcards
Lymph organs and tissues
Provide structural basis of the immune system and house phagocytic cells and lynphocytes
3 parts of the Lymohatic system
Lymphatic vessels
Lymph fluid
Lymph nodes
Lymphatic vessels
Networks of drainage vessels that collect excess protein containing interstitial fluid and return it to the blood stream and carry absorbed fats from intestines to the blood stream.
Lymphatic capillaries
Weave in and out of the blood capillaries and tissue. Blind-ended and and not tightly joined . Absent from bones teeth, marrow and the nervous system.
Lacteals
Specialized lymphatic capillaries that transports absorbed fats from intestines to blood. Chyle (fatty lymph)
Collecting lymphatic vessels
Same 3 tunics as veins but have thinner walls and more valves.
Lymphatic trunks
Large collecting vessels which drain fairly large areas of the bodies. Major trunks include: Paired: Lumbar Bronchomediastinal Subclavian jugular Single: Intestinal trunk
2 large ducts
Right lymphatic duct: drains lymph from the right upper limb and right side of the head and thorax
Thoracic duct: drains lymph from the rest of the body.
Lymphoid cells
Immune system cells found in lymphoid tissues and the supporting cells that for the scaffolding of these tissues.
Lymphocytes
T Cells: activate immune responce and some activly attack and destroy infected cells
B Cells: Protect the body by producing plasma cells (daughter cells that secrete antibodies into the blood)
Macrophages
Phagocyte foreign substances.
Reticular cells
Fibroblast-like cells that produce the reticular fiber stroma which is the network that supports the cells
Lymphoid tissue
Largely composed of reticular connective tissue
Diffuse lymphoid tissue: Loose arrangement of lymphoid cells and some reticular tissue
Lymphoid follicles: Solid spherical bodies consisting of tightly back B cells and reticular fibers
Lymph nodes
Primary organ of lymphatic system has 2 functions:
Filtration: macrophages in the nodes destroy organisms and debris
Immune system activiation
Node circulation
Afferent vessels: lymph enters the cortex
Efferent vessels: Blood exits the cortex
Lymph Organs
Lymph nodes Spleen thymus tonsils Peyer's patches
Spleen
Largest lymph organ Blood cleansing functions Stores products of RBC break down (Fe) Stores platelets for later use Fetal erythrocyte production
Pulp
White: where immune functions take place, lymphocytes hand here
Red pulp: where worn out RBC and pathogens are destroyed
Thymus
Where T cells mature
Most active during childhood
Has no follicles because it lacks T cells
Does not directly fight antigens
MALT
mucosa associated lymph tissue
Peyer’s patches
Appendix
Tonsils
Tonsils
Paired palatine tonsils: either side of the posterior oral cavity
Lingual tonsils: at the base of the tongue
Pharyngeal tonsils: posterior wall of nasopharynx
Tubal tonsils: surround the openings of the auditory tubes and the pharynx
Peyer’s Patches
Structurally similar to the tonsils
distal portion on small intestines
Appendix
Destroys bacteria before it can breach intestinal wall
Generate memory lymphocytes for long term immunity
