lymphatic system a&p unit 2

how is lymphatic system like a airport security line

how does lymphatic system mantain homeostasis

blood moves through high pressure circulatory system

lymphatic system takes up extra fluid and does a background check

mantains homeostasis by sending blood back

3 main parts of lymphatic system

network of lymphatic vessels: intimately associated with cardiovascular network

lymph: fluid in vessels

lymph nodes: cleanse lymph

Lymphatic Capillaries

blind ended tubes in which adjacent endothelial cells overlap to make mini valves

cell debris and pathogens go through, hit a lymph node (breakdown of debris)

Lymph

watery fluid, starts out as blood plasma

gets forced out of capillaries, helps with exchange, picked up by lymphatic capillaries

Lymph Nodes

checkpoints that monitor and cleanse liquid as it goes through

can release macrophages if detects cell debris or pathogens

if enlarged, shows signs of disease/infection

diffused throughout the body, not to much on lower, more on body trunk

macrophages to eat cell debris that comes by

Structure of Lymph Node

1. Fibrous Capusle (Cortex): germinal center, lymphoid follicle, sub-scapular sinus
   afferent lymphatic vessels: fluid coming in, goes into cortex
   Dendritic cells: identify antigens, activate T/B cells

2. Medulla: T/B, plasma cells
   lymph sinuses make area for macrophages to check for pathogens

Lymphatic System Characteristics

operates under low pressure, valves to prevent backflow, smooth skeletal muscle to keep lymph moving

returns fluid leaked from blood vessels back to blood

Lymphoid organs and tissues

provides structural basis of immune system by housing phagocytes and lymphocytes

ex. spleen, thymus, tonsils, lymph nodes

Types of Lymphoid Organs

Primary Lymphoid Organs: T/B Cells mature (thymus, red bone marrow)

Secondary Lymphoid Organs: mature lymphocytes, find/destroy pathogens (nodes, tonsil, spleen, appendix)

Spleen

high vascularization/blood, served by splenic artery (enter/exit at hilum)

lots of lymphocytes, cleanse old RBC/platelets

stores breakfown products of RBC (ex. iron) for later

White Pulp

Red Pulp

site where immune function occurs (lymphocyte on reticular fibers)

old blood cells + blood borne pathogens are destroyed

Where does lymph eventually end up

right lymphatic duct

thoracic duct

drains at junction of jugular vein and subclavian vein

drain fluid back into blood stream

Immune System Cells

lymphocytes: cells of adaptive immunity, mature into T cells or B cells (recognizes antigens)

macrophage: phagocytize foreign substances and help activate T cells

Mucos associated lymphoid Tissue

Found in mucous membrane (outside lymphatic vessels)

lymphoid tissues in mucous membranes throughout body

Tonsil

ring around entrance of pharynx, inspects anything you eat or breathe

palatine (largest, get infected)

lingual (base of tongue)

Pharyngeal (nasopharyngeal)

tubal (ear)

crypts in epithelium that lets bacteria get inside/destroy them

Peyers Patch

aggregated lymphoid nodules, small intestine

location aids in function: destroy bacteria (preventing them from breaching intestinal wall), generate memory lymphocytes

Appendix

can get enlarged/burst (location aids in function)

Thymus

area to help mature T cells (primarily through puberty)

capsule, cortex, medulla, thymic corpuscles (T cells developing)