06 Lymphatic System Review

lymphatic system

Network of lymphatic vessels, lymph, and lymph nodes. Provides defense against infection, absorbs dietary fats, and absorbs excess interstitial fluid

lymphatic capillaries

Small, open-ended lymph vessels that act like drain pipes which picks up lymph at tissues throughout the body and absorb proteins and dietary fats.

The flaplike minivalves of the lymph capillaries act like one-way swinging doors that allow lymph fluid to enter the lymph capillaries but not exit.

True

lymphatic vessels

large vessels with valves, which collect and carry lymph to lymph nodes

lymphatic trunks

jugular, subclavian, bronchomediastinal, intercostal, intestinal, lumbar

right lymphatic duct

drains right upper arm and right side of head and thorax

thoracic duct

receives lymph from the left side of the head, neck, chest, abdomen, left arm, and lower extremities

lymph nodes

Bean-shaped filters that cluster along the lymphatic vessels of the body. They function as a cleanser of lymph as wells as a site of T and B cell activation

capsule (lymph node)

dense fibrous that surround each lymph node

trabeculae (lymph node)

Extensions of the capsule creates division of the lymph node

Subcapsular sinus of lymph node

Afferent lymphatics deliver fluid from the tissues to it. contains cells that have encountered pathogens

lymphoid follicles (nodules)

solid, spherical bodies consisting of tightly packed lymphoid cells and reticular fibers

germinal centers

where B cells multiply and differentiate into plasma cells

Trabecular sinus of lymph node

(Green arrow) Sinus of lymph node that run parallel to trabeculae and lead inwards to a labyrinth of medullary sinuses

medullary sinus of lymph node

open spaces between medullary cords

(arrows pointing to lighter color)

medullary cord

dark staining "island" of cells in medulla; actually small extension of cortex made up of lymphocytes and plasma cells

afferent lymphatic vessels

bring lymph to a lymph node

efferent lymphatic vessels

Vessels leaving the lymph node

Spleen

Organ near the stomach that produces, stores, and eliminates blood cells. Not part of the lymphatic system but is a secondary organ.

red pulp of spleen

sinuses filled with erythrocytes

white pulp of spleen

lymphocytes, macrophages surrounding small branches of splenic artery

tonsils

masses of lymphatic tissue in the back of the oropharynx

pharyngeal tonsil (adenoids)

single tonsil on wall of nasopharynx

palatine tonsils

located on the left and right sides of the throat in the area that is visible through the mouth

lingual tonsils

located at the base of the tongue

Peyer's patches

large collections of lymphoid tissue found in the submucosa of the small intestine

What is chyle?

white or pale yellow substance in lymph that contains fatty substances absorbed by the lacteals

lacteals

specialized lymph vessels in the small intestine that absorb fat into the bloodstream

cisterna chyli

an enlarged pouch on the thoracic duct that serves as a storage area for lymph moving toward its point of entry into the venous system

T-cells

Found in the Thymus

B-cells

Found in the bone marrow

Humoral immunity

B cells produce antibodies after exposure to specific antigens

cell-mediated immunity

T cells that respond to antigens and destroy them directly

Thymus

degenerates (involutes) with age

Lymphadenitis

Found in common sites of metastatic cancer

Tonsilitis

Occurs in sites that often contains food debris, dead leukocytes, bacteria and antigenic chemicals

What is the first step in the route from tissue fluid to the bloodstream?

Lymphatic capillaries

What follows lymphatic capillaries in the route to the bloodstream?

Collecting vessels

How many lymphatic trunks are there in the route to the bloodstream?

6 lymphatic trunks

What comes after the lymphatic trunks in the route to the bloodstream?

2 collecting ducts

What is the next step after the collecting ducts in the route to the bloodstream?

Subclavian veins

What is the final destination in the route from tissue fluid to the bloodstream?

Right atrium

cervical lymph nodes

lymph from head and neck

axillary lymph nodes

upper limb and breast

thoracic lymph nodes

mediastinum, lungs, and airway

abdominal lymph nodes

urinary and reproductive systems

intestinal and mesenteric lymph nodes

digestive tract

inguinal lymph nodes

entire lower limb

popliteal lymph nodes

the leg proper