Lecture 10 Lymphatic System

Lymphatic Vessels

“Pick up” fluid lost from capillaries filters it & returns it to the bloodstream found everywhere but CNS, bones, marrow, teeth

Hydrostatic Pressure

“Pushes” fluid out of the capillary beds

Osmotic Pressure

exerted by plasma proteins (albumin); pulls fluid into the vessel

Net Loss 

Beginning capillary pushes 15mmHg pushing fluid out end of capillary 5mmHg fluid into capillary, More fluid leaves capillary than returned

Interstitial Space

Space filled with Interstitial fluid

Lymphatic Capillaries

Acts as minivalves open by interstitial pressure Interstitial fluid enters capillary = lymph, absorbs cell debris, pathogens, cancer cells

Lacteals

Specialized lymph capillaries in intestines, absorb digested fat, & deliver it to the blood

Right Lymphatic Duct

Drains right arm & right side of head & thorax

Thoracic Duct

Drains the rest of body (Ducts merge with large neck veins 

Primary Lymphatic Structures

Red bone marrow, Thymus gland

Secondary Lymphatic Structures

House Lymphocytes & Macrophages, lymph nodes, spleen, tonsils, MALT

Red Bone Marrow

located in spongy bone, all blood cells are produced here, T & B lymphocytes are WBC’S

Thymus

Only organ that doesn't fight antigens, secretes hormones T cell gain immunocompetence

Immunocompetence

Lymphocytes programmed to recognize & respond to specific antigens, located in sternum, grow until adolescence then atrophies

Antigen

Anything body perceives as foreign & provokes immune response as pathogens mismatched RBC, transplanted tissue, cancer cells

T Cells

Manage immune response attack & destroy foreign/infected cells

B Cells

produce plasma cells, secrete antibodies, immobilize antigens

Macrophage

Phagocytosis (Cell eating) help activate T lymphocytes

Lymph Nodes

Principal lymphatic organs, clustered along lymphatic vessels, surface of body of inguinal, axillary & cervical regions

Cortex

Replicating B cells

Afferent Vessels

Bring Lymph into node

Efferent Vessels

Carry lymph away increase time for filtering

Lymph Node Func.

Filtration (cleans lymph by destroying antigens & debris), activate lymphocytes - immune response initiated 

Spleen

Largest Lymphatic organ, storage site: Monocytes platelets, Fe++, highly vascularized

Hilum

Indented area where anything enters/exit the spleen

White Pulp

Lymphocytes initiate immune response+

Red Pulp

Macrophages clean blood

MALT

Mucosa-associated Lymphatic Tissue, found in respiratory & digestive tracts protects against antigens & housing lymphocytes, macrophages, 

Palatine Tonsils

Posterior oral cavity

Lingual Tonsils

Posterior (back) of tongue

Pharyngeal Tonsils

Posterior nasopharynx

Tubal Tonsils

Surround opening of auditory tubes into pharynx

Tonsils

Epithelial tissues overlying lymphatic tissues forming crypts, lymphocytes & macrophages wait in crypts and destroy pathogens