Lab 8 The Lymphatic System A&P2

What are the functions of the lymphatic system?

recycles lymph and immunity

What are the primary lymphoid organs and their function?

red bone marrow and thymus; to make/mature lymphocytes that defend the body

What are secondary lymphoid organs and their function?

lymph nodes, spleen, MALT, tonsils (three parts), and nodules; to protect/defend the body

thymus gland (function and location)

located in the mediastinal cavity, site of T-cell maturation, gets smaller with age, has 2 lobes

Where are the tonsils located and what are the three tonsils?

Located in the pharynx
the pharyngeal tonsil in the posterior wall of the nasopharynx
the palatine tonsils in the posterior oral cavity wall
the lingual tonsils at the root of the tongue

spleen

located in the abdominal cavity
blood reservoir and filters blood
has red and white pulp

red pulp

RBCs, looks light and is not nucleated

white pulp

lymphocytes, looks nucleated and purple

afferent lymphatic vessels

carry lymph to the lymph nodes, where it is filtered

efferent lymphatic vessels

transport filtered lymph away from the lymph node/spleen

MALT

Peyer's patches (an example) located within the walls of the small intestine, between the inner lining (mucosa) and muscle layers

Hassall's corpuscles

defining feature of the thymus, located in the medulla
looks like a ball/asteroid on the thymus cs

What are the hallmarks of inflammation?

redness, swelling, heat, pain, sometimes loss of function

The lymphatic vessel network, from smallest to largest, consists of:

Lymph capillaries→ lymph vessels→ lymph trunks → lymph ducts

inflammation response

damaged cells release chemicals into the interstitial fluid and produce cell debris
macrophages remove cell debris and/or pathogens by phagocytosis, also release chemicals signals that attract more phagocytic cells into the area
Mast cells release histamine
Histamine causes capillaries to vasodilate and be more permeable
Blood flow increases, bringing more WBCs and antibodies to fight infection and remove cell debris
localized tissue changes produce redness, swelling, heat, and pain
Pus is usually formed of dead WBCs, dead bacteria, cell debris, etc

cortex of lymph node

outer region of lymph node

medulla of lymph node

core of the lymph node

capsule of lymph node

connective tissue cover of lymph node

trabeculae of lymph node

internal extensions of the capsule that create divisions of the lymph node

What do valves do?

prevent back flow of blood

right lymphatic duct drains

right side of head, thorax, and right arm

thoracic duct drains and is the ___ duct

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

axillary lymph nodes

concentrated in armpit, receive lymph from upper limb (arms) and breast

cervical lymph nodes

drain and cleanse lymph coming from the head and neck areas

Inguial Lymph Nodes

purify lymph from legs

bronchomediastinal trunks

drain lymph from the thoracic cavity

cysterna chyli

an expanded sac; receives lymph from lumbar trunks and intestinal trunk; delivers lymph to thoracic duct