Chapter 20 and 21 - Chapter 20 Anatomy and 21 Physiology II Objective 1 Describe the lymphatic system A meandering network of lymphatic vessels and

Chapter 20 and 21 - Chapter 20 Anatomy and 21 Physiology II...

This preview shows page 1 - 15 out of 66 pages.

Chapter 20 Anatomy and 21 Physiology II
Image of page 1
Objective 1 Describe the lymphatic system. A meandering network of lymphatic vessels and various lymphoid organs scattered throughout the body The lymphatic system consists of 2 parts Lymphatic vessels that transport fluids that have escaped the blood system back to the blood Lymphatic organs house phagocytic cells and lymphocytes which function in body defense and resistance.
Image of page 2
Image of page 3
The lymphatic system is twice the size of the circulatory system. this means there is twice the amount of lymph fluid and blood. Acts as a collecting duct for excess fluids and as a filtering system to screen out foreign bodies. Objective 1
Image of page 4
Lymph – complicated network of tubes spaced throughout the body which drain fluid from surrounding tissue and back to bloodstream. Lymph fluid is filtered through the Spleen Thymus Lymph Nodes Objective 1
Image of page 5
Objective 2 Describe lymphatic vessels and note the differences between lymphatic vessels and arteries and veins. Define circulation pattern of lymphatic fluid. Lymphatic vessels form a one-way network capillaries collecting vessels trunks ducts fluid flows toward the heart. The right lymphatic duct and the thoracic duct empty lymph fluid into the blood vascular system in the neck.
Image of page 6
Objective 2 The lymphatic capillaries are blind-ended. The edges of their endothelial cells overlap, forming flap-like minivalves. Collagen filaments anchor the endothelial cells to surrounding structures so that an increase in interstitial fluid volume opens the minivalves. When the pressure is greater inside the capillary, the minivalve closes, preventing fluid from leaking back out.
Image of page 7
Objective 2 Highly specialized lymphatic capillaries called lacteals are present in the villi of the intestine where they play a role in absorbing digested fats. Lymphatic vessels are low-pressure vessels that use the same mechanisms as veins to return the lymph to the circulatory system.
Image of page 8
Image of page 9
Objective 3 Describe the structure of lymph nodes with respect to cells located in the cortex and medulla. At intervals along the lymphatic vessels, lymph flows through the lymph nodes. Each lymph node has a fibrous capsule, a cortex containing lymphocytes for the immune response plus a medulla containing mostly macrophages which engulf bacteria, viruses, and foreign material and may initiate an immune response
Image of page 10
Dendritic cells capture antigens and being them back to the lymph nodes. Reticular cells are similar to fibroblasts and produce the reticular fiber network of the lymph node Objective 3
Image of page 11
Afferent = flow into Efferent = flow out
Image of page 12
Objective 4 Identify other lymphoid organs and their functions. Spleen – site for lymphocyte proliferation destroys aged red blood cells stores and releases the breakdown products of hemoglobin site of rbc production in the fetus stores and releases blood in times of demand acts as a lymph node for the blood
Image of page 13
Objective 4 Thymus – During youth it functions in T cell development.
Image of page 14
Image of page 15

You've reached the end of your free preview.

Want to read all 66 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture