cardiovascular disease Flashcards
What are the cardiovascular diseases?
pericarditis
valve defects (stenosis and regurgitation)
-defects in the specialised excitatory and conductive system
-hypertension
-assorted congenital heart defects
What is the assorted congential heart defects?
- septal defects (hole in heart)- oxygenated and deoxygenated blood mix
- development of single ventricle
- coarctation of aorta (narrowing)- if blood vessel is too big, it will press on blood vessels underneath- causing narrowing
What is the structure of blood vessels?
Veins- bring blood to the heart
Arteries- take blood from the heart
Capillaries- gas and nutrient exchange
What is the structure of the arteries ?
Tunica Interna Endothelial cells Internal elastic lamina Tunica Media External elastic lamina Tunica Externa
What is the tunica interna made of in the arteries?
Why?
Simple smooth endothelium - it provides a frictionless surface for the movement of blood - so you dont get blood clotting
What are the endothelial cells?
- are continuous with heart and blood vessel
- have smooth frictionless lining for both blood vessels and heart
Location of the endothelial cells?
sits on the basement membrane
What is the internal elastic lamina?
separates the tunica interna from the tunica media
What is the inner layer of a blood vessel?
simple endothelium, sitting on a basement membrane, surrounded by internal elastic lamina
What is the bulk of the artery?
Tunica Media
What is tunica media composed of?
made of smooth muscle
What are arteries?
Mostly muscular
up to 40 layers of smooth muscle
some elastic and collagenous connective tissue.
Why are there muscles in blood vessels?
-To make blood vessels wide and narrow- to regulate B.P
- Close blood vessel down, if you are cut/injured
-Re-direct blood
But NOT to squeeze the blood along
What else does the tunica media have?
Nerve supply to artery- sympatheic ANS innervates smooth muscle of most arteries
What are in the larger vessels of the arteries?
Blood vessels in blood vessels -have vessels in their walls called Vasa Vasorum
What is the outer layer of the artery?
Tunica externa
What is the tunica externa made of?
- Several layers of longitudinal ,collagenous connective tissue- tough outer coat
Why are not all arteries the same?
They vary in thickness and composition of the various layers
- Closer to heart- arteries are larger
- Further to heart- arteries are smaller
What are the arteries closest to the heart known as?
Elastic/conducting arteries (with the same 3 layers)
What is different about these elastic arteries?
- They dont have that much smooth muscle in the tunica media
- Mainly have elastic tissue
What does the elastic property do in the arteries?
When the heart contract- blood is pushed into the arteries- it gets bigger and dilates
- When the heart relaxes- arteries collapse
- they even out the pressure of the heart contracting and relaxing
- The recoiling - helps push blood along
What are the muscular arteries?
- Like generalised artery - tunica media mainly consists of smooth muscle
- serve to distrubute blood to the different organs of the body
What are arterioles?
- They consist of endothelium with a bit of smooth muscle cells around them
- Small diameter = less than 0.5mm
- They regulate B.P
What are capillaries?
- exchange of nutrients and respiratory gases
- Small diameter = 7-9 um
length= 0.25-1mm
Distrubution depends on tissue- e.g. skeletal muscle have lots of capillaries, cornea have no capillaries
what are the 2 types of capillaries?
Continuous cappilary
What is the structure of the continuous capillary?
Adjacent endothelial cells (which sit on the basement membrane) are joined by tight junctions.
The exchange of nutrients go through the cells called Pinocytic vesicles