Exam 3 - Lymphatic and Respiratory Flashcards
What is an immune system?
It is not an organ system but a cell population that inhabits all organs and defends the body from agents of disease
What is the lymphatic system?
It is a network of organs and vein-like vessels that recover fluid, activate immune responses, inspect for disease agents, and return fluid to bloodstream
What is the lymphatic fluid recovery system?
Fluid continually filters from the blood capillaries into the tissue spaces
How much of the fluid goes into the lymphatic system?
15% (2 to 4 L/day) of the water and half the plasma proteins go into it and then are returned to the blood
What is lymph and what does it look like?
The recovered fluid. It is a clear, colorless fluid that originates as extracellular fluid
What are lymphatic vessels?
They are vessels that transport the lymph
What are lymphatic tissues?
They are composed of aggregates of lymphocytes and macrophages that populate many organs in the body
What are lymphatic organs?
Organs where defense cells are concentrated and are separated from surrounding organs by connective tissue capsules
What are lymphatic capillaries (also known as terminal lymphatics)?
They penetrate nearly every tissue of the body where it is closed on one end and covered by endothelial cells.
What doe lymphatic vessels do?
Converge into larger and larger vessels and have collecting vessels that go through many lymph nodes
What do the 6 lymphatic trunks do?
Drain major portions of body
What are the two collecting ducts?
Right lymphatic duct and thoracic duct
What does the right lymphatic duct do?
Receives lymph from right arm, right side of head and thorax; empties into right subclavian vein
What does the thoracic duct do?
It is larger and longer; and begins in a sac in the abdomen where it receives lymph from below the diaphragm and left side of the body where it empties into the left subclavian vein.
Where does most of the lymph go to?
The thoracic duct; it does the lower body and the left side of the upper body
When does lymph flow?
At low pressure and slower speed then venous blood
How is lymph moved through vessels?
Rhythmic contractions
What is the flow of lymph?
1- aided by skeletal muscle pump
2- arterial pulsation rhythmically squeezes lymphatic vessels
3- thoracic pump aids flow from abdominal to thoracic cavity
4- Valves prevent backward flow
5- the rapid flowing blood in subclavian veins draws lymph into it
What increases lymphatic return?
exercise
What are natural killer (NK) cells?
Large lymphocytes
What do NK cells do?
Attack and destroy bacteria, transplanted tissues, host cells that are infected, or turned cancerous
Where are T lymphocytes (T cells) matured?
In the thymus
What do B lymphocytes (B cells) do?
When activated causes proliferation and differentiation into plasma cells that then produce antibodies
What are Macrophages?
Antigen-presenting cells (APCs)