A&PII: Lab 3: The Lymphatic System Flashcards
Lymph
clear, yellowish liquid flowing in a 1-way direction toward the heart
Lymphatic vessels
lymph is transported by a system of these tubular vessels in a direction leading toward the heart
Primary lymphatic organs
organs containing stem cells that produce lymphocytes and serve as the site for their preparation to recognize unwanted substances and mount an immune response
Thymus
a primary lymphatic organ; soft, superior to the heart (larger in children, shrinks with age)
Red bone marrow
a primary lymphatic organ inside bones
Secondary lymphatic organs
contain WBC’s that are immunocompetent (ready to defend against unwanted substances
Lymph nodes
secondary lymphatic organs; small, pea-sized organs distributed along the lymphatic vessels in various regions of the body
Spleen
secondary lymphatic organ; soft organ located lateral to the stomach in the abdominal cavity
Lymphatic nodules
secondary lymphatic organs; clusters of lymphatic tissue that form aggregations throughout the body
Mucosa-associated lymphoid tissue (MALT)
one of the larger lymphatic nodules, found in the mucous membranes of the GI, respiratory, urinary, and reproductive tracts
Peyer’s patches
one of the larger lymphatic nodules; aggregated lymphatic follicles in the wall of the small intestine
Bronchial nodules
one of the larger lymphatic nodules; in the walls of the bronchi
Tonsils
one of the larger lymphatic nodules; found in the mouth and throat
Pharyngeal tonsil
tonsil in the posterior wall of the nasopharynx
Palatine tonsils
paired tonsils in the posterior oral cavity wall
Lingual tonsils
paired tonsils at the root of the tongue
Lymphatic capillaries
lymph originates when interstitial fluid finds its way into these microscopic, blind-ended structures
Lymphatic vessels
from the capillaries, lymph flows into these structures
Lymph nodes
as lymph flows in a direction toward the heart, it passes through numerous of these structures, which are stationed in regional locations within the lymphatic vessel pathway; filters lymph of unwanted materials due to the WBC’s residing within them
Lymphatic ducts
the lymphatic vessels channel lymph into these larger vessels, which eventually merge with the subclavian veins near the heart
Thoracic duct
one of 2 major ducts; drains most of the body into the left subclavian vein
Right lymphatic duct
shorter of 2 major ducts; drains into the right subclavian vein
Cysterna chyli
the thoracic duct receives lymph from a convergence of abdominal lymphatic vessels forming this expanded sac
Capsule
each lymph node consists of this outer fibrous connective tissue that includes trabeculae
Trabeculae
internal extensions of the capsule of a lymph node, forming a network of tiny compartments
Reticular tissue
connective tissue occupying the compartments of trabeculae within a capsule of a lymph node; contains protein fibers that support reticulocytes
Reticulocytes
specialized fibroblasts supported by reticular tissue; their function is to support developing lymphocytes
Cortex
outer section of the interior of a lymph node
Medulla
inner section of the interior of a lymph node
Lymphatic nodules
the cortex and medulla of a lymph node contain these, which contain large numbers of WBC’s (mainly lymphocytes and macrophages); usually ovoid in the cortex and narrow in the medulla
Medullary cords
lymphatic nodules that are narrow in the medulla
Germinal center
the center of each lymphatic nodule consists of this, which contains dividing lymphocytes
Afferent vessels
lymph enters a node by way of these structures, which unite with the lymph node at its capsule
Subcapsular sinus
once inside a node, lymph passes through this cavity, then enters the spaces between trabeculae
Trabecular sinuses
cavities filled with reticular tissue and WBC’s
Medullary sinuses
cavities into which lymph drains before exiting a lymph node
Efferent vessels
lymph exits a node by way of 1 or 2 of these structures
Hilus (lymph node)
the efferent vessels exit from this slight depression in a lymph node
Splenic artery
the spleen receives a large supply of blood by way of this artery
Splenic vein
the spleen is drained by this vein
Hilus (spleen)
the splenic artery and vein merge with the spleen at a depression known as this
Efferent lymphatic vessels
carry lymph away from the spleen
White pulp
part of the spleen characterized by an abundance of WBC’s (mainly lymphocytes); appears dark purple under the microscope (due to nucleated cells –> nucleic acids)
Red pulp
part of the spleen characterized by the abundance of RBC’s, due to its function of RBC storage; due to a lack of nuclei, this appears relatively light under the microscope
Thymic lobes
the external capsule of the thymus extends inward to divide it internally into these 2 sections
Lobules
each thymic lobe divides further into these numerous structures, each of which consists of an outer cortex and an inner medulla
T cells
1 of 2 classes of lymphocytes; differentiate within the cortex of the thymus
B cells
1 of 2 classes of lymphocytes; differentiate within red bone marrow
Hassall’s corpuscles
the medulla of the thymus contains these distinctive structures, each of which consists of a circular arrangement of reticular cells
