Cardiovascular disease Flashcards
What is most cardiovascular diseases related to
Blood vessels, not heart
What is major cause of death in US
Heart disease - 26.6%
Stroke = 5.9% = 3rd
What are the cardiovascular diseases?
- Pericarditis
- Valve defects
- Defects in the specialised excitatory and conductive system
- Hypertension - high b.p
- Assorted congenital heart defects
What is Pericarditis
Inflammation of pericardium
Acquired disease
Won’t kill you but lead to conditions that might kill you
Fluid pericardium produces too much pressure on heart or too little - heart beating in envionment with not enough lubrication = heart function less efficiently
What are the two types of valve defects
Stenosis
Regurgitation
= valves not opening enough - too narrow = blood flows back down heart
What involves heart not functioning properly
- Wont beat properly
- Won’t push out as much blood
- Disrupt normal rhythm
What are the 3 defects in the specialised excitatory and conductive system
- Tachycardia and Bradycardia - heart beat too slow/fast
- Ventricular fibrillation - heart high frequency contractions
- Ectopic pacemaker - another part of system takes over
- Heart block - break in B.Of.His
What does specialised excitatory and conductive system allow
Heart maintain regular contraction without input from nervous system
What is the assorted congential ( born with ) heart defects?
- Septal defects
- Development of single ventricle
- Contraction of aorta (narrowing)- if blood vessels too big, it will press on blood vessels underneath- causing narrowing
What is Septal defect
(Hole in heart)- oxygenated and deoxygenated blood mix between 2 ventricles - sometimes hole doesnt completely close between left and right ventricle
What is contraction of aorta as defect
If blood vessels too big, it will press on blood vessels underneath- causing narrowing
What is the structure of blood vessels - 3 broad categories
Veins
Arteries
Capillaries
What do veins and arteries act as
Pipes - take blood from A - B, no gas exchange
Veins- bring blood to the heart
Arteries- take blood from the heart
Role of capillaries
Gas and nutrient exchange
What are the 3 layers of the arteries
Tunica Interna
Tunica Media
Tunica Externa
What is the role of tunica interna
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
- have smooth frictionless lining for both blood vessels and heart
Location of the endothelial cells?
sits on the basement membrane
What is the role of internal elastic lamina?
separates the tunica interna from the tunica media
What is the inner layer of a blood vessel?
Tunica interna
simple single squamous epithelium, sitting on a basement membrane, surrounded by internal elastic lamina
What is the bulk of the artery - middle layer ?
Tunica Media
How many layers are arteries made up of
3
What are arteries mostly made of
Mostly muscular
up to 40 layers of smooth muscle
some elastic and collagenous connective tissue.
Which arteries are close to heart
Big arteries - aorta
Elastic/conducting arteries with elastic properties
Which arteries are further down from heart
Smaller arteries and capillaries
What can the tunica media be innervated by
The sympathetic branch of the ANS
What supplies the tunica media and externa of larger vessels
Vaso Vasorum
Blood vessels in blood vessels -have vessels in their walls called Vasa Vasorum
How do different arteries vary
In the thickness and composition of various layers
What is it internal elastic lumina
Elastic layer of connective tissue
How often does tunica interna turn over
At a rate of 5% of endothelial cells a day
Two properties of the endothelial cells
- Sits on basement membrane
- Continuous with heart, smooth frictionless lining of blood vessels and heart
What don’t elastic arteries have so much of
Have little smooth muscle
Why are arteries elasticated
Allows them to smooth out the blood flow near the heart
What happens to arteries when heart contracts
Blood pushed into these arteries and gets bigger - dilate
What happens to arteries when heart relaxes
Due to their elastic properties, they collapse down which evens out pressure
What do muscular arteries have a tunica media composed of and what is role
Primarily smooth muscle
Distribute blood and change diameter
What do elastic ( conducting ) arteries have a tunica media composed of
Elastic tissue laminae
What is tunica media mostly made of
Concentric layers of smooth muscle
What don’t you want muscles in blood vessels to do
To contract and squeeze or move blood along
What do you want muscles in blood vessels to do
To make blood vessels wide and narrow to regulate b.p = redirect blood
Close blood vessels down if it gets injured
Close down circulation in bits of body when its cold = close down blood supply to finger and toes = gets cold outside to keep up core temp
What else does the tunica media have?
Nerve supply to artery- sympatheic NS innervates smooth muscle of most arteries
What does the tunica media mostly have
Smooth muscle and collagenous elastic connective tissue
What can’t you do if you have a big artery
Supply tunica media from blood in lumen of vessel so big vessels have vessels in their walls = vasa vasorum - vessels of vessels
What is the role of external elastic lumina
Separate tunica media from tunica externa
What is the outer layer of artery called and what is it made of
Tunica externa AKA Adventitia - several layers of longitudinal colagenous connective tissue = tough outerprotective coat
What does recoil of arteries help to do
Push blood along
What does contracting and relaxing of smooth muscle of tunica media do
Distribute blood to different organs and regions of body
Where are muscular arteries found
Further down system
What is different about these elastic arteries?
- They dont have that much smooth muscle in the tunica media
- Mainly have elastic tissue
What are the arteries closest to the heart known as?
Elastic/conducting arteries (with the same 3 layers)
What is diameter of arterioles
Small diameter = less than 0.5mm
What is role of arterioles
Regulate bp
What do arterioles consist of
Endothelium with a bit of rings of smooth muscle cells around them
What dont arterioles have
3 coats or layers
What is diameter, length and total surface area of capillaries
Small diameter = 7-9 um
length= 0.25-1mm
Total length in body = 96,000km with surface area 6000m2