Anatomy Flashcards
Name the components of the lymphatic system
- Lymph vessels
- Lymph nodes
- Spleen (produces lymphocytes)
- Thymus gland
- Bone marrow of long bones
- Lymph nodules (tonsils and peyers patches)
What are the functions of the lymphatic system?
- Return protein and water from the interstitium to the cardiovascular system
- Absorb fat and fat soluble vitamins
- Immune defense: recognises and responds to foreign cells/ microbes. Produces lymphocytes (white blood cells)
The lymphatic system is multilayered and divided into 3 parts. Name the 3 layers.
- Superficial system which lies just below the skin
- Deep system in the muscles, joints and organs
- Visceral system in the intestines
Describe the process of lymphatic transport
Transport begins in the interstitial space
- Fluid and proteins enter the lymphatic capillary
- It passes through pre-collectors
- To the collector
- Into the lymph nodes
- To the lymphatic ducts and trunks
- To join with the venous system in the cervical region
Why can lymph capillaries absorb larger molecules such as proteins than blood capillaries?
Lumen is larger
Describe the cell wall of a lymph capillary
Made up of flat endothelial cells. It’s basement membrane has anchoring filaments which anchor to tissues and open flaps. There is no muscular component
Where does interstitial fluid enter the lymph capillaries?
Though the endothelial gaps to become lymph
What does lymph consist of?
Fat
Cells (red blood cells, white blood cells and lymphocytes)
Proteins
Water
Waste products and foreign objects
How do lymph capillaries opens?
Fluid pressure increases in the interstitium, anchor filaments are stretched and allow junctions between the endothelium cells to open and fluid poors in
What is the role of pre collectors?
Pre collectors gather lymph from the capillary area and move fluid towards the collectors
Pre collectors are located just below the surface of the skin in the du dermal tissue
Where are collecting vessels located?
Within both superficial and deep systems
Collecting vessels collect what percentage of lymph load from the initial lymphatics? And transport in which direction through the regional nodes?
80%
Distal to proximal
What is each section of a collecting vessel called and what is it bordered by?
Each section is called a lymphangion and is bordered by proximal and distal bicuspid valves. It is the smallest unit of a lymph collector
What nervous system innervates lymphangion activity?
Automatic
How many intrinsic contractions will a lymphangion produce each minute?
6-10
What extrinsic factors influence lymphangion contractions?
Diaphragmatic breathing
Muscle movement
Arterial pulsation
Negative pressure in the central veins
External compression
What propels fluid movement?
Compulsion from behind, constant production of lymph
Lymphangion activity caused by the autonomic nervous system
Negative pressure in central veins
What extrinsic factors propel fluid movement?
Breathing; changes in intra thoracic and intra abdominal pressure during respiration ( provides pressure to cisterna chyli
Arterial pulsation which causes pulsation to lymphatic system
External stretch and pressure (MLD and garments)
Passive and active limb movements due to muscle pump. The muscle squeezes lymphangion
How many lymph nodes are in the body?
600-700
How big and what shape is a lymph node?
2-30mm long and shaped like a kidney bean
What are the functions of lymph nodes?
Filtering station for noxious matter
Production of white blood cells
Regulate the concentration of proteins in the lymph
Where are the main groups of lymph nodes in the body?
Cervical lymph nodes
Axillary lymph nodes
Iliac lymph nodes
Inguinal lymph nodes
Popliteal lymph nodes
Where do the upper extremity and upper trunk drain in to?
Axillary lymph nodes
Where do the lower extremity, lower trunk and external genitalia drain to?
Inguinal lymph nodes
