Anatomy, Lymph Nodes | Summaries Health psychology

Assignment on lymph nodes

Importance of lymph nodes:

Your lymph nodes are located throughout your body, including your:

 neck and back (cervical lymph nodes)

 armpits (axillary lymph nodes)

 groin.

 stomach.

 chest.

 The lymphatic system is composed of lymphatic vessels and lymphoid organs such as the thymus,

tonsils, lymph nodes, and spleen. These assist in acquired and innate immunity, in filtering and

draining the interstitial fluid, and recycling cells at the end of their life cycle. The fluid that leaks

from end-stage capillaries returns to the vascular system via the superficial and deep lymphatic

vessels, which in turn drain into the right lymphatic duct and the thoracic duct. The right lymphatic

duct travels on the medial border of the scalenus anterior muscle and drains the lymph from the

right upper quadrant of the body. The thoracic duct starts at the cisterna chyli and has highly

variable anatomy. The right lymphatic duct and the thoracic duct drain into the right and left

subclavian arteries, respectively, at the jugulovenous angle.

 Lymph nodes are found at the convergence of major blood vessels, and an adult will have

approximately 800 nodes commonly sited in the neck, axilla, thorax, abdomen, and groin. These

filter incoming lymph and play a role in infection as well as in malignancy. This paper will discuss

the structure and function of lymph nodes, as well as the anatomical divisions of these.

 Structure and Function

 Lymph nodes are kidney-shaped and receive lymph via multiple afferent vessels, and filtered

lymph then leaves via one or two efferent vessels. Nodes typically have an associated artery and

vein, which terminates into a high endothelial venule (HEV). The HEV is the site of trans-

endothelial migration of circulating lymphocytes due to T and B-cell endothelial surface receptor

 Lymph nodes usually range in size from 1 to 2 cm and are enclosed in an adipose tissue capsule.

Normal size depends upon location, as well as the axis which is being measured. The long axis

should be 1 cm or less. They are considered pathological if they lose their oval shape, if there is a

loss of the hilar fat, if there is an asymmetrical thickening of the cortex and if they are persistently

enlarged.

 Lymph Node Structure

 Capsule

 The capsule of the lymph node is dense connective tissue stroma and collagenous fibers. The

capsule sends trabeculae inside the lymph node, which pass inward, radiating towards the center.

 Subscapular Sinus

 The subcapsular sinus is the space between the capsule and the cortex, which allows the

transportation of the lymphatic fluid.; this is also called the lymph path, the lymph sinus, or the

marginal sinus. The subcapsular sinus is present beneath the capsule and is traversed by both

reticular fibers and cells. It receives the afferent vessels, continues with the trabecular sinuses, and

joins the medullary sinus in the medulla of the lymph node.

 Cortex

Partial preview of the text

Download Anatomy, Lymph Nodes and more Summaries Health psychology in PDF only on Docsity!

Assignment on lymph nodes

Importance of lymph nodes:

Your lymph nodes are located throughout your body, including your:

 neck and back (cervical lymph nodes)  armpits (axillary lymph nodes)  groin.  stomach.  chest.  The lymphatic system is composed of lymphatic vessels and lymphoid organs such as the thymus, tonsils, lymph nodes, and spleen. These assist in acquired and innate immunity, in filtering and draining the interstitial fluid, and recycling cells at the end of their life cycle. The fluid that leaks from end-stage capillaries returns to the vascular system via the superficial and deep lymphatic vessels, which in turn drain into the right lymphatic duct and the thoracic duct. The right lymphatic duct travels on the medial border of the scalenus anterior muscle and drains the lymph from the right upper quadrant of the body. The thoracic duct starts at the cisterna chyli and has highly variable anatomy. The right lymphatic duct and the thoracic duct drain into the right and left subclavian arteries, respectively, at the jugulovenous angle.  Lymph nodes are found at the convergence of major blood vessels, and an adult will have approximately 800 nodes commonly sited in the neck, axilla, thorax, abdomen, and groin. These filter incoming lymph and play a role in infection as well as in malignancy. This paper will discuss the structure and function of lymph nodes, as well as the anatomical divisions of these.

 Structure and Function

 Lymph nodes are kidney-shaped and receive lymph via multiple afferent vessels, and filtered lymph then leaves via one or two efferent vessels. Nodes typically have an associated artery and vein, which terminates into a high endothelial venule (HEV). The HEV is the site of trans- endothelial migration of circulating lymphocytes due to T and B-cell endothelial surface receptor  Lymph nodes usually range in size from 1 to 2 cm and are enclosed in an adipose tissue capsule. Normal size depends upon location, as well as the axis which is being measured. The long axis should be 1 cm or less. They are considered pathological if they lose their oval shape, if there is a loss of the hilar fat, if there is an asymmetrical thickening of the cortex and if they are persistently enlarged.  Lymph Node Structure  Capsule  The capsule of the lymph node is dense connective tissue stroma and collagenous fibers. The capsule sends trabeculae inside the lymph node, which pass inward, radiating towards the center.  Subscapular Sinus  The subcapsular sinus is the space between the capsule and the cortex, which allows the transportation of the lymphatic fluid.; this is also called the lymph path, the lymph sinus, or the marginal sinus. The subcapsular sinus is present beneath the capsule and is traversed by both reticular fibers and cells. It receives the afferent vessels, continues with the trabecular sinuses, and joins the medullary sinus in the medulla of the lymph node.  Cortex

 The cortex of the lymph node is the layer beneath the subcapsular sinus. The cortex is formed of the outer cortex and the inner part known as the paracortex. The outer cortex layer is also named the B-cell layer, is rich in CXCR5 chemokines, and consists mainly of B-cells arranged into follicles. The immature B-cells develop into a germinal center when challenged with an antigen. Following this, resting B-cell and dendritic cells surround the germinal center to form a mantle zone. The paracortex layer, also called the T-cell layer, consists of T-cells that interact with the dendritic cells and is rich in CCR7 chemokines.[5]  Medulla  The medulla is the innermost layer of the lymph node and contains large blood vessels, sinuses, and medullary cords. The medullary cords contain antibody-secreting plasma cells, B-cells, and macrophages. The medullary sinuses (or sinusoids ) are vessel-like spaces that separate the medullary cords. The medullary sinuses receive lymph from the trabecular sinuses and cortical sinuses and contain reticular cells and histocytes. The medullary sinus drains the lymph into the efferent lymphatic vessels.  Function of Lymph Node [6]  The primary function of lymph nodes is filtering interstitial fluid collected from soft tissues and eventually returning it to the vascular system. Filtering this exudative fluid allows for exposure of T- cells and B-cells to a wide range of antigens. For antigen-specific B and T cells to activate, they must first suffer exposure to antigens with the aid of antigen-presenting cells, dendritic cells, and follicular dendritic cells. These form part of both the innate immune response and play a role in adaptive immunity. 

Anatomy, Lymph Nodes, Summaries of Health psychology

Related documents

Partial preview of the text

Download Anatomy, Lymph Nodes and more Summaries Health psychology in PDF only on Docsity!

 Structure and Function