1. Fall 2017 Anatomy and Physiology Lab II Dr. Santos
The Lymphatic system
Fall 2017
Anatomy and Physiology Lab II
Dr. Santos

2. What is the lymphatic system?
The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.

3. Three main functions
1- Transporting excess interstitial fluid back to the heart
2- Activating the immune system
3- Absorbing dietary fat.

4. transporting excess interstitial fluid back to the heart
The lymphatic system picks up lost fluids, carries it through lymphatic vessels and returns it to the cardiovascular system.
Lymph capillaries first pick up the fluids. Their walls are highly permeable to large substances and large volumes of liquid.
The lymph is then delivered to larger lymph collecting vessels  drain into larger lymph trunks  drain into lymph ducts  drain into the cardiovascular system

5. 2 Lymph ducts
Right lymphatic duct- drains the right arm, right side of the head, neck, and thorax.
Thoracic duct- drains the remainder of the body
The right lymphatic duct and the thoracic duct drain lymph into the blood at the junctions of the right and left subclavian and internal jugular veins, respectively.

8. Activating the Immune system
Some lymphatic organs such as the spleen, thymus and tonsils activate the Immune system.
Thymus- where T cells mature
Spleen- filters the blood and houses phagocytes.

9. tonsils
Tonsils- aggregates of un-encapsulated lymphoid tissue found in the oropharynx and nasopharynx. They help fight off germs that come in through your nose and mouth. Your tonsils try to prevent germs from causing infections in other areas of your body. Your tonsils usually do a really good job of fighting off infections. Sometimes, though, viruses or bacteria get into your tonsils and cause an infection in them. Three main sets of tonsils;
Pharyngeal tonsils- located on the posterior nasopharynx
Palatine tonsils- located on the posterior oropharynx
Lingual tonsils- located on the base of the tongue

10. Malt (mucosal associated lymphoid tissue)- scattered throughout the gastrointestinal tract
Lymph nodes- are encapsulated by connective tissue. Are found along lymphatic vessels where they function in filtering lymph and remove pathogens, toxins, and abnormal cells such as cancer cells and virus infected cells.
Peyer's patches are small masses of lymphatic tissue found throughout the ileum region of the small intestine. They form an important part of the immune system by monitoring intestinal bacteria populations and preventing the growth of pathogenic bacteria in the intestines.

12. Absorbing dietary fat
Fat molecules are too big to enter blood capillaries directly from the small intestine. Fat molecules enter a lymph capillary bed called a lacteal.
From the lacteal  delivers fat to a large lymphatic vessel called Cisterna chyli  thoracic duct