Lecture 6 - Anatomy of the circulatory system Flashcards
What is the main function of a circulatory system?
Transport
What are the three different types of circulatory systems?
Blood
Specialised
Lymphatic
What is the blood circulatory system?
A closed circuit where arteries carry blood away from and veins carry blood in to the heart
How are arteries and veins arranged across the body?
They have a generally identical distribution
Arteries and veins correspond and follow the same path, but take blood in different directions
Tissues and organs are serviced by them which anastomose with each other
What is systemic circulation?
The circuit where blood is taken from the heart to the body and back again
A high pressure system
What is pulmonary circulation?
Where the blood is taken from the heart to the lungs to become oxygenated and then returns
What is portal circulation?
A specialised circulation system
During systemic circulation blood passes through a portal vessel
Blood draining from one capillary bed passes through a vein to a second capillary before returning to the heart
What is an example of a portal circulation?
The hepatic portal system, which functions between the gastrointestinal tract and the liver
The blood exits the 1st capillary bed, enters the hepatic portal vein and enters the 2nd capillary bed
What is foetal circulation?
A specialised circulation system
In foetuses the lungs liver and gastrointestinal tract aren’t developed enough so are bypassed
What is lymphatic circulation?
A circulatory system involving lymph vessels, lymph and lymphatic tissues
What is the function of the lymphatic system?
Involved in defence mechanisms
Allows for the drainage of interstitial fluid
How is excess interstitial fluid removed?
It occurs in capillaries
At the arterial end, fluid moves into the interstitial space
At the venous end, the fluid moves back into the capillary
15% is left behind and enters the lymphatic capillary as lymph
What is the process of lymphatic drainage?
Lymph capillaries
Lymph vessels
Lymph nodes
Lymph trunks
Thoracic duct/right lymphatic duct
Left/Right subclavian vein
What are lymph nodes?
Encapsulated clusters of lymphocytes located along the lymphatic vessels
They filter the lymph and trap foreign particles, some of which are destroyed by macrophages
How is the lymph fluid distributed into the right lymphatic duct and thoracic duct?
Right lymphatic duct = Right side of head, neck, thorax and arm
Thoracic duct = everything else
