week 4 - cardiovascular physiology Flashcards
What is pathophysiology?
Deranged function in an individual or an organ that is due to disease
What is aetiology/
It is the science that deals with the cause/origin of disease
What is clinical epidemiology?
The study of populations in order to determine the frequency and distribution of disease
What is histopathology?
The study of microscopic anatomical changes in diseased tissue
What is cytopathology?
The study of disease changes within individual cells or cell types.
What is cardiovascular function based on/
- Cardiac pumping ability
- Integrity of vasculature
- Blood volume/composition.
What is cardiac pumping ability?
How able the heart is able to contract and the ability of the electrical signal of the pacemaker
What is integrity of vasculature?
there capacity of the blood vessels to exert their function
e.g. structural integrity
What is the importance of blood volume/composition?
Having the right balance of water and electrolytes.
Having the right lipid composition
What conditions can you get if there are issues with cardiovascular function?
Hypertension,
heart attacks
thrombosis
aneurysm
angina
What are the 3 blood vessel layers?
(variable between vessel types)
Tunica Intima
Tunica Media
Tunica externa
Describe the Tunica Intima?
It is the innermost layer, it lines the lumen
Made up of endothelial cells, basement membrane and internal elastic lamina
Describe the Tunica Media/
The middle layer.
Made up of elastic fibres and smooth muscle so that it can stretch
Describe the Tunica externa?
It is the outermost layer.
Made up[ of elastic tissue and collagen
Howe is the structure of the artery related to its function?
Arteries carry blood away from the heart to the rest of the body at a HIGH pressure so has a more narrow lumen and thicker arterial walls so the blood can get flow through the artery at a high pressure.
How is the structure of capillaries related to its function/
Capillaries are only 1 cell thick (made of endothelium, basement membrane)
This is so there is a fast exchange between substances
Also has a high surface area for fast exchange
How is the structure of veins related to its function?
Has valves to prevent the back flow of blood.
Blood is carried at a low pressure which can result in pooling and clotting of blood.
Muscle contraction promotes venous return (the return of blood back to the heart)
What 2 condition can affect the structure/function of blood vessels?
Atherosclerosis
Hypertension
What is atherosclerosis?
It is when fatty materials deposits develop in the walls of medium/large arteries.
As a result, the blood vessel loses elasticity, hardening of vessel walls and narrowing of lumen.
What are some modifiable risk factors off atherosclerosis?
hyperlipidaemia
hypertension
Smoking
Diabets
Some infection
What are some non modifiable risk factors of atherosclerosis?
Age
Gender
Genetics
What are the steps that occur to develop atherosclerosis?
- Injury to endothelium
- Vessel permeability changes, endothelium dysunctions the leukocytes
- Smooth muscle cells migrate
- Lipid accumulates
- Mature plaque produced
Describe what hypertension is ?
It is when you have high blood pressure - a blood pressure greater than 140mmHg
Can be the result of another condition
The patient can be predisposed to heart attack, stroke, heart failure etc
What are the consequences of atherosclerosis?
It weakens the blood vessel wall, causing an aneurysm
The plaque can rupture and promote blood clotting, causing thrombosis/embolism
The plaque may grow and block the artery which is called stenosis
What are the non modifiable risk factors of hypertension?
Age
Gender
Genetics
What are the modifiable risk factors of hypertension?
High sodium intake
Excessive alcohol
Obesity
Stress
Atherosclerosis and hypertension risk factors are kinda similar because they are linked???
The body tries to maintain blood pressure in the blood vessels within a narrow range.
What happens if blood pressure becomes too high?
It can damage a blood vessel, maybe even rupture it, which can cause bleeding.
High blood pressure also makes the heart work harder/
What is an aneurysm?
It is failure of the vessel wall. - blood filled dilation, bulge of the blood vessel
Can be caused by Hypertension and atherosclerosis as it weakens the vessel wall
If the aneurysm bursts, you get a drop in blood pressure and reduced tissue perfusion (the lack of oxygenated blood to areas of the body)
Can also promote blood clot formation.
What is LaPlace’s Law?
It is where arterial wall tension is proportional to pressure times radius of the arterial conduit.
IT IS A POSITIUVE FFEDBACK LOOP - so as the diameter of the b load vessel increases, wall tension increases which promotes further diameter increase
What is thrombosis/embolism?
It is where the blood vessels become blocked.
The blood vessels can become blocked by:
blood clots
fat
air
gas
Infected thrombus
Small tissue fragments
What is Virchow’s Triad?
Virchow’s triad describes 3 factors that contribute to the development thrombosis.
What are the 3 factors from Virchow’s triad that contribute towards an embolism>?
Changes in the wall of the blood vessel
Changes in blood flow - turbulence, stasis
Changes in blood constituents
What are the consequences of thrombus / embolism formation?
Stroke
Pulmonary embolism
Ischaemic limb
Deep vein thrombosis
Describe overall, what happens when there is a blockage or a rupture of a blood vessel?
- If you have a blockage (thrombus/embolus) or a rupture (burst aneurysm), this can lead to the stopping of the perfusion of a region.
- This can lead to ischaemia or infarction
- The results of this are dependent on the region affected.
What is acute myocardial infarction?
Also known as a heart attack.
This is when the blood supply to the heart is blocked.
What is ischaemia and what can it cause?
It is a condition in which blood flow and oxygen are restricted/reduced to a part of the body.
This can cause tissue damage/death
What are some risk factors of myocardial infarction?
angina
previous MI (myocardial infarction) or stroke
smoking
alcohol
diabetes
What is a stroke?
An interruption of blood supply to some / all of the brain.
Can be caused by thrombosis, embolism or haemorrhage
What can a stroke cause in the brain>?
The interruption of blood supply can cause ischaemia which can cause reduced neuronal function which can cause neuronal death (irreplaceable neurons)
How are strokes categorised?
They are categorised by whether they are caused by an aneurysm or thrombosis/embolism
What can poor blood flow cause/
It can lead to deep vein thrombosis - which is the formation of blood clots (thrombus’) in the deep veins.
Why are the legs affected by distension?
Because when standing, the veins in the leg have to push blood upward to reach the heart against gravity.
What are varicose veins?
They are abnormally enlarged superficial veins in the leg.
