Cardiovascular System Flashcards
How common is CV disease?
Main cause of death in Western countries
Responsible for half of deaths in Europe
What is Cardiovascular disease described as?
A term used to describe conditions which affect blood vessels or the heart
Group of disorders, Frequently fatal because efficient blood flow supports the whole of the body and organs
What is the structure of Arteries?
- Tunica Intima
- Tunica Media
- Tunica Adventitia
What is the Tunica Intima?
Inner layer of the artery (closest to lumen)
Single layer of endothelial cells (like blood vessels)
In direct contact with blood
What is the endothelium?
Physical barrier
Controls passage of substances from blood to tissues and vice versa
What are the functions of the Endothelium?
Participates in many functions e.g.
- Regulates vascular function
- Dilation or constriction of muscle to control artery lumen size
- Inflammatory responses (e.g. cytokines)
What is the function of the Tunica Intima?
Thin layer of connective tissue and internal elastic lamina separates the endothelium from the next layer
Basement membrane
Role is to support the endothelium (anchors it to the arterial wall)
What is the Tunica Media?
‘Middle layer’
Smooth muscle cells : arranged in concentric circles which permits the artery to change in diameter
What is the external elastic lamina?
The connective tissue which separates the tunica media from the outer layer of the vessel
Also provides structural support
What is the Tunica Adventitia?
Outer layer of blood vessel wall
Composed of cells (e.g. fibroblasts) and connective tissue
The connective tissue helps maintain the structure and integrity of the blood vessel
How do vessels work in Tunica Adventitia?
Large vessels have their own blood supply (vaso vasorum)
Oxygen and nutrients cannot diffuse from the lumen to the outer layer
What is artheroscelrosis?
Is initiated caused by the deposition of lipids in the arterial wall
What are lipoproteins composed of?
Composed from lipid and protein
Are a family of substances that have different functions and properties
Size, density, composition
What is the common function of lipoproteins?
To transport lipids
What is the structure of lipoproteins?
- Spherical
- Hydrophobic lipid core e.g. cholesterol
- Outer layer of phospholipids and apolipoproteins important for structure and targeting)
What are the different lipoproteins (from big to small)?
- Chylomicrons
- Very low density lipoproteins (VLDL)
- Intermediate density lipoproteins (IDL)
- Low density lipoproteins (LDL)
- High density lipoproteins (HDL)
What different lipids can lipoproteins carry?
Cholesterol, cholesterol esters, triglycerides, fatty acids, phospholipids
Where are lipoproteins produced?
Are mainly produced in the liver and intestine
Within the circulation, they are dynamic structures
Constant state of flux
What are chylomicrons?
Made in the intestine
Derived from lipids in the diet
Made by intestinal epithelium and secreted into blood
Deliver dietary fats (mainly triglycerides) to peripheral tissues which is used for energy
Where are VLDL’s synthesized?
Synthesized in the liver
Secreted into blood
Where is VLDL taken up?
By peripheral tissues
Lipid used for energy and storage by body
VLDL is converted to IDL and LDL (in blood/peripheral tissues/liver)
Where are LDL’s taken up and what is the main lipid component?
LDL taken up by cells via LDL receptors
(receptor mediated endocytosis)
Main lipid component- cholesterol
How is excess LDL removed and what is the main protein component of LDL?
Excess LDL removed by liver and this controls circulating concentration of LDL
(apo)B100 is the main protein component of LDL