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Lymphatic Anatomy Study Guide


Lymphatic Anatomy Lab Assignment

Lymphatic System:

Anatomy and Histology

lymphatic system
I). General Function

A). Fluid Balance

Lymphatic system absorbs fluid from the interstitial tissues which is called lymph and it passes back into the blood.

B). Fat Absorption

Absorbs fat (chyle)

C). Defense

II). Lymphatic Vessels and the Cardiac System

A).  Lymphatic vessels are found in close association to the cardiovascular system.

B). There is no pump and lymphatic pressure is very low

C).  One way system

D). Lymph is moved by:

i. skeletal muscle action

ii. changes in thoracic pressure

iii. pulsation of nearby arteries.


III).   Structure of the Lymphatic Vessels

A).  Lymphatic Capillaries

1).  The lymphatic vessels begin with the ‘blind-ended’ lymphatic capillaries  between the interstitial tissues & cardiovascular system

2). Characteristics of lymphatic capillaries

3). Lacteals

B). Lymphatic Collecting Vessels

 1).  Three distinct tunics

  • tunica interna
  • tunica media
  • tunica externa

2). Valves


3).  Collecting vessels are more superficial


Vessel histology


  • Valve


lymphatic valve



C). Lymphatic Trunks

1).  union of large collecting vessels.


2).  Named for the regions

i).  Intestinal Trunk

ii).  Lumbar Trunk

iii). Bronchmediastinal Trunk

iv). Subclavian Trunk

v). Jugular Trunks

Lymphatic System

D). Lymphatic Ducts

Drain in to the subclavian vein

1). Thoracic duct

2). Right lymphatic duct


Cisterna chyli:   An enlarged abdominal sac


IV). Lymphoid Cells

A). Macrophages (monocytes)

B). Lymphocytes

1)  Agranular white blood cell


2). Responsible for immunocompetence response. 


3).  Types of Lymphocytes

i). T lymphocytes (T cells)

ii). B lymphocytes (B cells)

C). Dendritic cells

D). Reticular cells

The lymphoid organs are encapsulated collections of diffuse lymphatic tissue that is made up of reticular connective tissue.

V). Lymphatic Follicles

A).  Structure:

i. Germinal centers (that stain lighter)

ii. With B lymphocytes

lymphatic follicle
B).  Aggregates of Lymphatic Follicles

1).  Mucosa-Associated Lymphatic Tissues

Found in the tracts of the respiratory and digestive systems.


2).  Peyer’s patches

Isolated patches of lymphatic follicles found around the intestine

peyer's patches



3).  Appendix




VI). Lymphoid Organs

A). Lymph Nodes

1). Location:

i.  cervical nodes

ii. axillary nodes

iii. inguinal nodes

iv. pelvic nodes

v. abdominal nodes

vi. thoracic nodes

vii supratonchlear nodes

lymph nodes

2). Function


3). Structure of Lymph Nodes

i).  Capsule outer covering

ii). Internal  Regions:

a). Cortex:  contain lymphatic follicles or nodules  with germinal centers

b) Medulla

iii).  Afferent lymphatic  vessels (arrive) bring lymph into the lymph node


iv).  Efferent lymphatic vessels (exit) leave the lymph node through the hilus.

Lymph node

Lymph node histology


  • lymphatic follicle

  • germinal center


lymph node histology



B). Spleen

1). Location

2). Functions

i).   salvages the breakdown products of red blood cells

ii).  stores platelets

iii).  lymphocyte proliferation

3). Structure

i). Blood vessels

  • splenic artery
  •  splenic vein

ii). Regions


Spleen histology


  • red pulp

  • white pulp


Spleen Histology


C). Thymus

1).  Location

2).  Function:

Secretes thymosin and thymopoietin

which causes t-lymphocytes to become immunocompetent.

3).  Structure-Histology

  • thymic lobules which are each divided into regions:

  • Cortex:  outer (darker) region

  • Medulla:   inner (lighter) region


Thymus histology


  • lobule

  • cortex

  • medulla

Thymus histology


http://home.hawaii.rr.com/dochazenfield/Tonsillectomy.htm http://www.healthopedia.com/pictures/palatine-tonsil.html

1. Pharyngeal Tonsil
2. Palatine Tonsil
3. Lingual Tonsil

D). Tonsils

1). Location

2). Named by location

i).   Palatine tonsils

ii).  Lingual tonsils

iii). Pharyngeal tonsils

iv). Tubal tonsils

3). Structures (histology)

Not completely encapsulated with blind end structures that are called crypts that trap bacteria.

Tonsil histology


  • crypts

Tonsil histology