6. Cardiovascular System - Part 2 Flashcards
Describe the difference between the ‘systemic circulation’ and ‘pulmonary circulation’.
There are the two types of circulation in the body
Systemic circulation:
BLOOD FROM THE HEART is distributed AROUND THE BODY before RETURNING TO THE HEART
Pulmonary circulation: BLOOD FROM THE HEART is distributed TO THE LUNGS before RETURNING TO THE HEART
What is meant by hepatic first pass
This describes the blood flow from the digestive system to the liver via the portal vein where we basically drain all of the contents of the digestive system and process them through the liver
Name the three layers of the blood vessel wall
(From the outside in)
Tunica Externa
Tunica Media
Tunica Intima
The same three layers exist in arteries, arterials, veins and venules but in different thicknesses. Capillaries only have a single layer which is tunica intima.
Think of it like a garden hose where the outer layer is TUNICA EXTERNA, the middle layer of plastic is TUNICA MEDIA and the inner layer is TUNICA INTIMA. Inside that is the water running through the hose which is the blood.
How do veins prevent the backflow of blood
They have valves that prevent the blood from going backwards
What type of blood vessel plays a key role in regulating blood pressure?
Arterioles. They are more muscular and under high pressure are better able to regulate blood pressure.
Name the four heart chambers in order of flow
There are four cavities in the heart through which the blood flows one chamber at a time starting at the right and moving to the left.
RIGHT ATRIUM to RIGHT VENTRICLE to LUNGS to LEFT ATRIUM to LEFT VENTRICLE.
The Atria are the arrival or receiving chambers of the heart (think atrium/entrance hall) , receiving venous blood. The atria pump blood into the ventricles
What vessel between the heart and the lungs carries deoxygenated blood?
Pulmonary artery
Where is the pulmonary valve located
The right Ventricle pumps blood into the lungs through the pulmonary valve into the pulmonary trunk which divides into the left and right pulmonary arteries.
So the pulmonary valve is located between the right ventricle and the pulmonary arteries
Is the right or left ventricle thicker? Why is one side thicker?
The left ventricle is thicker @ 10-15mm. This is because when it contracts it needs to pump the blood around the entire body. The right ventricle only needs to pump blood to the lungs so not as much force/pressure/muscle needed
Does the left atrium contain oxygenated or deoxygenated blood
Oxygenated
Label the hearts conductive system
The conductive system are the nerve structures that signal to the heart when the heart muscle needs to contract. Without the conductor system the heart can’t contract.
SA Node: Contraction of
Sino Atrial Node in the right atrial wall is the pacemaker of the heart. It sets the rate and the rhythm for the rest of the conductive system. It initiates the conduction system, sending a signal to the ….
AV Node: Signals are gathered
Atrial ventricular node which is between the atrium and the ventricles in the bottom right of the interatrial septum is the relay station gathering electrical signals.
Bundle of His: Through the Bundle of His
These signals from the AV node ascend through the bundle of his conducting from the Atria to the ventricles.
Right and left bundle branches: Impulse enters right and left bundles
The Bundle of His separates into the right and left bundle branches and spread out heading down towards the apex of the heart right at the bottom.
Purkinje fibres: Ventricular contraction
Purkinje fibres are where the bundle branches terminate. They conduct the nerve impulse from the apex of the heart up the sides of the heart branching out into the purkinje fibres.
Describe in specific detail the conduction system in the heart, commencing with the sinoatrial node (include all key structures and their functions).
WE know the heart is a muscle pumping blood through the chambers and out of the ventricles but something needs to tell the heart when to contract and in what order to do it. It is a very fast wave and it must be done in a specific order.
The conductive system of the heart are the nerve structure that signal to the heart when the heart muscle needs to contract. Without the conductive system the heart cannot contract.
- Sinoatrial Node (SA Node) CONTRACTION OF ATRIA
SA NODE is located in the right atrium. This ‘PACEMAKER OF THE HEART’ initiates cardiac contraction and sets the rate. Nerve impulses from the SA node causes Atrial contraction - Atrioventricular Node (AV Node) – SIGNALS ARE GATHERED
Located between the atrium (atrio) and the ventricles (ventricular). Bottom right of the interatrial septum.
It is a RELAY STATION. It gathers in the electrical signals and conducts them at a slightly slower rate to allow the atria to finish contracting. - Atrioventricular bundle (Bundle of His) – THROUGH BUNDLE OF HIS
The AV node gathers the electrical signals and sends them down through the middle of the heat through the Bundle of His. - Right and left bundle branches – IMPULSE ENTERS RIGHT AND LEFT BUNDLES
Now the electrical signals need to start going to the left and right side of the heart so the Bundle of His separates into the right and left bundle branches. They spread out and head down towards the apex of the heart at the bottom. - Purkinje Fibres - VENTRICULAR CONTRACTION
These are the terminal branches of the right and left branches.
The Purkinje fibres rapidly conduct the nerve impulse beginning at the apex of the heart spreading up the sides of the heart and this is when we get ventricular contraction forcing the blood upwards and out of the heart.
What is meant by autorhythmic
It refers to the heart regulating its own rhythm and rate
What is the term describing a pulse rate over 100 BPM?
Tachycardic
What is meant by systole? Does this represent the top or the bottom number when reading blood pressure.
Systole is the force of the hearts contraction and the amount of pressure that builds up in the blood vessels when the heart contracts. It is the top number on a blood pressure reading.
What is the effect of the sympathetic nervous system on heart rate and strength of contraction?
When in fight or flight, the heart rate goes up and contractions are stronger to allow more blood to pump through the body giving oxygen for action.
Outline the key steps in the formation of atherosclerosis. (need to know this perfectly)
1) Damage to the vascular endothelium wall (tunica intima) of the artery, creating inflammation
Damage can be from high blood pressure, high glucose, high insulin which is associated with high cholesterol, transfers, smoking, alcohol, sedentary lifestyle etc
2) LDL’s (cholesterol) deposit in the tunica intima to repair the damage but they become oxidised and therefore unstable and they attract white blood cells (macrophages) to help out.
3) Macrophages try to engulf and destroy LDL, the fatty material. But they have trouble and end up covering the whole area. This results in the creation of foam cells which are cells packed with fat.
At this point we have a bit of an issue and a bit of lump.
4) Vascular smooth muscles proliferate to try to stabilise
5) wrap around the foam cells to create a cap of plaque and separate it from the blood but in doing so for protective reasons it reduces the space for blood to flow.
Now we have a narrowed passage in the lumen
What are the risk factors for atherosclerosis
Sex and age (men > 45 years); Family history; Ethnicity – South Asian, African, Caribbean
Diet: High trans fats, insulin resistance; high refines sugar; obesity; alcohol; gut or oral dysbiosus
Lifestyle: stress, sedentary, smoking
What is the difference between a stroke and TIA (Transient Ischaemic Attack)
Both associated with Ischaemia (lack of blood supply) to part of the brain but symptoms of TIA does not long last long – Impaired function for no longer than 24 hours. Someone could have a TIA and not know.
What is the usual cause of a myocardial Infarction (aka heart attack)
Death of myocardial tissue due to ischaema (lack of blood supply) usually caused by a blockage of the coronary artery by a thrombus (clot).
List three symptoms of pericarditis.
Pericarditis is acute inflammation of the pericardium which is the outer layer of the heart. It is attached to the diaphragm so when breathing in and drawing the diagram into the abdomen you are pulling the pericardium sac which is inflamed and painful.
3 symptoms:
1) Chest pain: radiating to the back and relieved by sitting up and forward. Worsened by lying down or breathing deeply.
2) Dyspnoea: when reclining
3) Fever (because this is an infection generally)
Compare the main symptoms of left and right sided heart failure
Right:
* Systemic Oedema because right sided heart failure will affect the venous system leading to backflow and pooling of blood more broadly
* Ascites
* Portal hypertension due to backflow of blood into the portal vein
Left
* Pulmonary Oedema because blood backflow from left atrium into lungs
* Congestion bronchitis
* Cardia Asthma (with coughing often most severe at night)
Explain what is meant by an aneurysm.
Abnormal local dilations of the arteries due to weakness of the vessel wall (Often secondary to atherosclerosis)
Two common examples are:
Abdominal aortic aneurysm Where the abdominal aorta expands Leading to a tearing pulsating sensation of the abdomen and lower back
Berry aneurysm which manifest as a very bad explosive headache and may lead to a haemorrhage stroke
What are the major risk factors of a DVT?
- Lack of movement /inactivity- leads to reduced blood flow. Blood becomes stagnant and sits and pools. Hospital stays; long haul fights
- Varicose veins as this suggests that blood is not circulating well.
- Changes in blood composition making it more viscous such as severe dehydration, polycythemia, sticky platelets and the oral contraceptive pill.
- Damage to blood vessel wall
What are the common causes of haemorrhoids?
Chronic Constipation
Pregnancy
Chronic cough
portal hypertension
Obesity
Describe two possible complications of pericarditis?
Constrictive pericarditis - the sack should be nice and flexible to allow the heart to pump easily. This complication means it is thickened, scarred and fibrotic.
Cardiac tamponade - the pericardium is a serous membrane which means that it has two layers of membrane with fluid in between. Constructive pericarditis is where you have a pericardial effusion meaning a collection of fluid within the space between the serious membranes. The fluid can build up and limit space for the heart.
Describe the main role of capillaries.
There are three main types of blood vessels - arteries, veins and capillaries.
Capillaries are small blood vessels connecting arterials and venules.
They specialise in the EXCHANGE OF SUBSTANCES between blood and cells/tissues
What vessel between the heart and lungs carries deoxygenated blood.
This is the pulmonary artery. The exception to the ruke that arteries carry oxygenated blood. It carries deoxygenated blood away from the heart towards the lungs
With regards to blood vessels, complete the following table:
Direction/location?
Blood content?
Pressure?
Valves?
Direction/Location?
Arteries and arterioles carry blood AWAY from the heart
Veins and venules carry blood TOWARDS the heart
Blood content?
Arteries and arterioles have Oxygenated * blood
Veins and venules have Deoxygenated blood
Pressure?
Arteries and arterioles have high pressure because oxygen is demand all the time
Veins and venules low pressure because there is not the same urgency
Valves?
Arteries and arterioles - no valves
Veins and venules - valves prevent backflow of blood in a system that is slow and low in pressure
*In most cases arteries carry oxygen and veins carry carbon dioxide but not always. There are exceptions. The two main ones are pulmonary and umbilical arteries and veins
Describe how the structure of capillaries supports its main role.
Capillaries are made-up of a single layer of cells to ease exchange of substances.
It is only at the level of capillaries that we are exchanging substances. Arteries are too thick but we can’t go straight from arteries to capillaries so we have an intermediate level known as arterioles.
Which muscle type supports the return of venous blood to the heart?
SKELETAL MUSCLE. It’s contraction aids return of venous blood to the heart.
The pumping action of the HEART is also a major drive. The respiratory pump (DIAPHRAGM) also aids return
Where is most of the blood found in the body?
64% in the venous system – veins and venules
13% in arteriole system – arteries and arterioles
9% in pulmonary system (the network between the heart and lungs)
7% in capillaries
7% in the heart
Explain the role of the ‘portal vein’.
All of the blood that drains the digestive organs get funnelled into a system of veins and ultimately into one vein - the portal vein - which goes into the liver
So the vessel that carries the absorbed substances through the hepatic first pass is known as the portal vein.
Think of the portal like a gateway into the rest of your circulation. The liver then filters it. By the time the blood comes out of the liver and goes up to the heart it is filtered. If there was something in the gut that could be harmful it would be filtered out.
Explain how the following affects blood pressure:
a. Vasoconstriction
b. Vasodilation
a. Vasoconstriction increases blood pressure.
SYMPATHETIC NERVOUS SYSTEM. When stressed the sympathetic nervous system sends impulses to the arteries and arterials telling them to constrict. This INCREASES BLOOD PRESSURE.
b. Vasodilation reduces blood pressure as there is more area though which it can flow.
With regards to the heart complete the following:
Heart sits in the thoracic cavity within the thorax. It rests on the ………. near the midline of the thoracic cavity pointing ……….. The heart is covered anteriorly by the ………. and ribs 3-6. The apex of the heart is formed by the left ………. and lies in the ………. intercostal space.
Heart sits in the thoracic cavity within the thorax. It rests on the DIAPHRAGM near the midline of the thoracic cavity pointing LEFT. The heart is covered anteriorly by the STERNUM and ribs 3-6. The apex of the heart is formed by the left VENTRICLE and lies in the FIFTH intercostal space.
Name the three layers of the heart as well as their location, function and structure
Endocardium
Innermost layer of heart
Provides a SMOOTH LAYER for the heart chambers and covers heart valves
A LAYER OF ENDOTHELIUM overlying a thin layer of connective tissue
Myocardium
Middle layer of heart
Functions to PUMP blood out of the heart and lungs
Consists of CARDIAC MUSCLE and makes up 95% of the heart
Pericardium
Outer layer of heart
Functions to keep the heart in position within the thorax and allow FREE MOVEMENT during contractions
Thin double layered membrane made up of (i) a FIBROUS PERICARDIUM that attaches to the diaphragm and (ii) an inner SEROUS fluid PERICARDIUM
Name the heart layer that contains cardiac muscle.
Myocardium
What is the aorta?
The main and largest artery in the body.
The left and right coronary arteries are the first branches of the aorta and supply the MYOCARDIUM with an abundance of oxygenated blood.
Describe specifically the flow of blood in the heart from entering via the right atrium to exiting via the aorta. Include all key structures and indicate if blood is oxygenated or deoxygenated.
DEOXYGENATED STAGES
1. DEOXYGENATED blood into RIGHT ATRIUM via SUPERIOR and INFERIOR VENA CAVA
2 RIGHT ATRIUM pumps blood into the RIGHT VENTRICLE through the TRICUSPID VALVE
3 RIGHT VENTRICLE contracts and pumps the DEOXYGENATED BLOOD up through the PULMONARY VALVE and into the PULMONARY TRUNK.
4 The ULMONARY TRUNK. divides into the LEFT and RIGHT PULMONARY ARTERIES.
5 Blood flows through the lungs. Gas exchange occurs
OXYGENATED STAGES
6 OXYGENATED BLOOD returns to the LEFT ATRIUM via the PULMONARY VEIN
7 The LEFT ATRIUM pumps the OXYGENATED blood through the BICUSPID/MITRAL VALVE into the LEFT VENTRICLE
8 LLEFT VENTRICLE contracts and pumps OXYGENATED BLOOD through the AORTIV VALVE into the ASCENDING AORTA
9 Some of the OXYGENATED BLOOD in the aorta flows into the CORONARY ARTERIES which carry blood to the heart wall
What vessel between the heart and lungs carries deoxygenated blood.
This is the pulmonary artery. The exception to the ruke that arteries carry oxygenated blood. It carries deoxygenated blood away from the heart towards the lungs
Describe how the structure of capillaries supports its main role.
Capillaries are made-up of a single layer of cells to ease exchange of substances.
It is only at the level of capillaries that we are exchanging substances. Arteries are too thick but we can’t go straight from arteries to capillaries so we have an intermediate level known as arterioles.
Describe the structure of the 3 layers of blood vessels
Tunica intima
Innermost layer of ENDOTHELIUM (endothelial tissue). Contains epithelium to PROTECT the vessel wall and functions to secrete chemicals.
This layer is in direct contact with blood and is well positioned to monitor and respond to changes
Tunica media
Layer of smooth muscle that controls blood vessel diameter.
In arteries and arterioles tunica media is the thickest layer. It is more muscular and under high pressure plays an important role in blood pressure regulation.
Capillaries do not have this layer
Tunica externa
Outermost layer. Made of ELASTIC AND COLLAGEN FIBRES. Contains nerves and small blood vessels. Capillaries do not have this layer
For veins and venules tunica externa is the largest because of the slow pace of veins it needs to stretch to allow pooling of blood.
Indicate which transport process supports capillary exchange of:
a. Gases
b. Nutrients
c. Water
a. Gases – Carbon Dioxide and Oxygen by DIFUSSION
b. Nutrients – Glucose, fats, vitamins, minerals etc by FACILITATED DIFUSSION and ACTIVE TRANSPORT
c. Water – OSMOSIS. This is a passive transport meaning no ATP is needed. Water is move down the concentration gradient.
Explain the role of the ‘portal vein’.
All of the blood that drains the digestive organs get funnelled into a system of veins and ultimately into one vein - the portal vein - which goes into the liver
So the vessel that carries the absorbed substances through the hepatic first pass is known as the portal vein.
Think of the portal like a gateway into the rest of your circulation. The liver then filters it. By the time the blood comes out of the liver and goes up to the heart it is filtered. If there was something in the gut that could be harmful it would be filtered out.
Explain how the following affects blood pressure:
a. Vasoconstriction
b. Vasodilation
a. Vasoconstriction increases blood pressure.
SYMPATHETIC NERVOUS SYSTEM. When stressed the sympathetic nervous system sends impulses to the arteries and arterials telling them to constrict. This INCREASES BLOOD PRESSURE.
b. Vasodilation reduces blood pressure as there is more area though which it can flow.
Which nervous system stimulates vasoconstriction?
Automatic nervous system which is made up of the sympathetic, parasympathetic and enteric nervous system. All the blood vessels except the capillaries contain smooth muscles which are influenced by the autonomic nervous system.
Is the sympathetic nervous that stimulates vasoconstriction
With regards to the heart complete the following:
Heart sits in the thoracic cavity within the thorax. It rests on the ………. near the midline of the thoracic cavity pointing ……….. The heart is covered anteriorly by the ………. and ribs 3-6. The apex of the heart is formed by the left ………. and lies in the ………. intercostal space.
Heart sits in the thoracic cavity within the thorax. It rests on the DIAPHRAGM near the midline of the thoracic cavity pointing LEFT. The heart is covered anteriorly by the STERNUM and ribs 3-6. The apex of the heart is formed by the left VENTRICLE and lies in the FIFTH intercostal space.
Name the three layers of the heart as well as their location, function and structure
Endocardium
Innermost layer of heart
Provides a SMOOTH LAYER for the heart chambers and covers heart valves
A LAYER OF ENDOTHELIUM overlying a thin layer of connective tissue
Myocardium
Middle layer of heart
Functions to PUMP blood out of the heart and lungs
Consists of CARDIAC MUSCLE and makes up 95% of the heart
Pericardium
Outer layer of heart
Functions to keep the heart in position within the thorax and allow FREE MOVEMENT during contractions
Thin double layered membrane made up of (i) a FIBROUS PERICARDIUM that attaches to the diaphragm and (ii) an inner SEROUS fluid PERICARDIUM
Name the heart layer that contains cardiac muscle.
Myocardium
Describe specifically the flow of blood in the heart from entering via the right atrium to exiting via the aorta. Include all key structures and indicate if blood is oxygenated or deoxygenated.
DEOXYGENATED STAGES
1. DEOXYGENATED blood into RIGHT ATRIUM via SUPERIOR and INFERIOR VENA CAVA
2 RIGHT ATRIUM pumps blood into the RIGHT VENTRICLE through the TRICUSPID VALVE
3 RIGHT VENTRICLE contracts and pumps the DEOXYGENATED BLOOD up through the PULMONARY VALVE and into the PULMONARY TRUNK.
4 The ULMONARY TRUNK. divides into the LEFT and RIGHT PULMONARY ARTERIES.
5 Blood flows through the lungs. Gas exchange occurs
OXYGENATED STAGES
6 OXYGENATED BLOOD returns to the LEFT ATRIUM via the PULMONARY VEIN
7 The LEFT ATRIUM pumps the OXYGENATED blood through the BICUSPID/MITRAL VALVE into the LEFT VENTRICLE
8 LLEFT VENTRICLE contracts and pumps OXYGENATED BLOOD through the AORTIV VALVE into the ASCENDING AORTA
9 Some of the OXYGENATED BLOOD in the aorta flows into the CORONARY ARTERIES which carry blood to the heart wall
What is the aorta?
The main and largest artery in the body.
The left and right coronary arteries are the first branches of the aorta and supply the MYOCARDIUM with an abundance of oxygenated blood.
- Describe the role of ‘ductus arteriosum’?
During foetal development we don’t need to send blood to the lungs because a foetus is not breathing. It is getting oxygen through the placenta via the umbilical cord.
There are two adaptations at the foetal stage to deal with this – pass blood and miss the lungs altogether.
The Foramen Ovale shunts blood from the right atrium to the left atrium to bypass the lungs.
The ductus arteriosum is a temporary blood vessel that shunts blood from the pulmonary trunk to the aorta. It closes after birth to form ligamentum arteriosum.
- Describe the role of ‘ductus arteriosum’?
During foetal development we don’t need to send blood to the lungs because a foetus is not breathing. It is getting oxygen through the placenta via the umbilical cord.
There are two adaptations at the foetal stage to deal with this – pass blood and miss the lungs altogether.
The Foramen Ovale shunts blood from the right atrium to the left atrium to bypass the lungs.
The ductus arteriosum is a temporary blood vessel that shunts blood from the pulmonary trunk to the aorta. It closes after birth to form ligamentum arteriosum.
Explain what is meant by ‘auto-rhythmic’.
A unique property of cardiac muscle is its ability to generate its own rhythm of contraction. This is what is meant by auto-rhythmic.
The muscle contracts in response to nerve impulses so we need a system of nerves there. Therefore embedded in the myocardium are lots of nerves that travel through the heart in a certain pattern
List FOUR factors that influence heart rate and strength.
Hormones
Age
Sex
Body position
Exercise
Stress
Temperature
White coat syndrome
Explain how the following affects heart rate and contraction:
a. Sympathetic nervous system
b. Parasympathetic nervous system
Although there is a basic rhythm by which the heart beats, this is verridden by the sympathetic and parasympathetic nervous system to speed it up or slow it down.
a. Sympathetic nervous system
Fight or flight system
INCREASES RATE AND STRENGTH OF CONTRACTION – faster & stronger
Vasoconstriction increases blood pressure
b. Parasympathetic nervous system
Rest and digest
DECREASES RATE AND STRENGTH OF CONTRACTION via the VEGUS nerve
Little influence on blood vessels
Describe the role of the sinoatrial node.
It is the PACEMAKER OF THE HEART.
- It initiates cardiac conduction located in the RIGHT ATRIAL WALL
- It also sets the rate and rhythm for the rest of the conductive system
- Sends out a nerve impulse which spreads across the right and left atrium and going towards the ventricle and CAUSING ATRIAL CONTRACTION.
Indicate where the sinoatrial node is in the heart.
In the RIGHT ATRIAL WALL
Which type of respiration does cardiac muscle require?
Aerobic. It is an aerobic organ with a limited capacity to work under oxygen debt
The heart is 95% muscle. It accounts for 1% of body weight but 10% of oxygen consumption.
Name the predominant fuel used by cardiac muscle?
FATTY ACIDS are the predominant fuel used in cardiac muscle (50-70%) followed by glucose (30%)
Name the product that the heart can use to produce ATP during exercise.
LACTIC ACID can produce small amounts of ATP.
Explain what is meant by ‘pulse rate’.
The pulse is a blood pressure wave originating from the heart. The pulse rate refers to the number of waves per minute
What is the average adult pulse rate?
70-90
The rate varies throughout childhood being higher in newborns and toddlers youngsters. The smaller you are the higher the pulse rate because your heart is smaller (lower cardiac output) and needs to contract more often.
Define cardiac output.
Cardiac output is the volume of blood being pumped out by the heart per minute.
On average this is 5 lites per minute
Explain the following terms:
a. Tachycardia
b. Bradycardia
c. Systole
d. Diastole
Explain the following terms:
a. Tachycardia
Resting heart rate > 100 beats per minute
b. Bradycardia
Resting heart rate < 60 beats per minute
c. Systole
The force that drives blood out of the heart - CONTRACTION FORCE
The maximum amount of pressure.
d. Diastole
Period of RELAXATION when the heart fills with blood. This is the smallest pressure that you ever find in your cardiovascular system.
You need a certain amount of pressure or the blood would pool at your feet and you would faint immediately.
According to the NHS, what are the normal ranges of blood pressure?
Blood pressure refers to the pressure created and exerted by circulaying blood on the bood vessel walls.
Systolic/Diastolic: 90/60 to 140/90
If too low insufficient to keep the constant delivery of blood. Vasodilation lowers blood pressure
If too high damages the inside of blood vessels. Vasoconstriction increases blood pressure.
Name TWO organs which have the highest priority for blood in the body.
Brain and Heart
State TWO functions of cholesterol.
We cannot survive without cholesterol. It is in EVERY cell in our body. It is a vital compound for cell structure and function. However in excess it might become part of the pathogenesis of atherosclerosis.
Key functions include:
- Cell membrane integrity
- Vitamin D and calcium metabolism.
- Synthesises sex hormones
Describe how cholesterol is transported around the body.
Cholesterol is hydrophobic so it needs to be bound to a HYDOPHYLIC PROTEIN. It travels around the body as a LIPOPROTEIN.
Think like cholesterol is the passenger and the bus is the protein.
- Explain the function of the following:
a. Low density lipoproteins (LDL)
b. High density lipoproteins (HDL)
a. Low density lipoproteins (LDL)
Without LDL we would not be alive. It’s role is to get cholesterol to all the parts of the body including the brain, the arteries etc. It carries 75% of the total cholesterol in the blood carrying it from the LIVER TO THE CELLS IN THE BODY.
Think of like a large bus carrying most of the cholesterol.
LDL is the cholesterol often referred to as ‘bad cholesterol’ but this is too simplistic. It is only when present in excess that it can batter the arteries triggering atherosclerosis. Higher LDL correlates with a longer life expectancy and cn be good in a healthy person but in the context of an unhealthy person, not so good.
Also LDL numbers on their own do not give the context. It is the ratio between LDL and HDL.
b. High density lipoproteins (HDL)
HDL REMOVES EXCESS CHOLESTEROL FROM BODY CELLS AND BLOOD AND TRANSPORTS THIS EXCESS TO THE LIVER. Its job is to PREVENT THE ACCUMULATION OF CHOLESTEROL in the blood.
Smaller bus for carrying HDL than LDL.
Note:
High LDL + low inflammation = low risk of cardiovascular disease
High LDL + high inflammation = high risk of cardiovascular disease
Describe in detail the pathophysiology of atherosclerosis.
Atherosclerosis refers to the narrowing and hardening of arteries in large and medium sized arteries. It results in reduced blood flow. Think of a shower head clogged up with limescale.
Step 1:
Damage of the vascular endothelium wall (tunica intima) in the artery occurs, creating INFLAMMATION.
The damage can be caused by
- high blood pressure
- free radicals due to poor diet, toxins etc, causing oxidative stress
- Hyperglycaemia.
Step 2:
LDL’s come on to repair the damage in the endothelial wall but get stuck because there is constant damage and inflammation due to step 1. Therefore, it stays to keep repairing but are then oxidised and become unstable, subsequently attracting phagocytes.
So they come in due to oxidative stress but then are the subject of oxidative stress themselves.
Step 3:
The immune system is not happy, It sends out MACROPHAGES to engulf the oxidised mess of fatty material in an attempt to destroy it. They get stuck too. Foam cells (cells packed with fat) result.
Step 4:
Next vascular SMOOTH MUSCLE proliferates.
Step 5:
We move smooth muscle to create a cover over the resulting plaque to wall it off from the blood but all the while we are taking up more and more space in the artery.
Name FOUR dietary/lifestyle causes of atherosclerosis.
- Obesity
- Hyperglycaemia – High blood sugar levels/insulin resistance/diabetes. Insulin is the hormone that pushes glucose into your cells. If cells are no longer responsive to insulin glucose does not get in. The glucose just sits in the blood building up and leading to hyperglycaemia.
- Smoking – increases inflammation
- Stress/high blood pressure
- Obesity – drives inflammation
- Poor diet leading to gut/oral dysbiosis and intestinal permeability
- Sedentary lifestyle
- Excess alcohol
Non dietary/lifestyle causes include being male, hereditary, age over 45 for men and 55 for women.
Describe TWO main ways that atherosclerosis presents clinically.
Atherosclerosis is the genesis of most cardiovascular disease.
Angina Pectoris/Myocardial infarction
Stroke// transient ischaemic attacks/aneurisms
Explain why an embolism is a serious complication of atherosclerosis.
It can lead to a stroke
List FOUR causes of hypercholesterolemia.
Hyper – high cholesterol- cholesterol emia – in the blood
- FAMILIAL – defect on chromosome 9 which causes an inability to remove LDL from the blood.
- Risk increases with AGE
- DIET – high refined sugars makes your liver produce more LDL cholesterol; trans fats; table salt
- SEDENTARY lifestyle
- DIABETES MELLITUS
- OBESITY – much higher chance of insulin resistance
- Excessive alcohol
- Smoking
Define Ischaemic?
Inadequate blood supply to organ or tissue, starving it of blood.
Define angina pectoris.
Ischaemic heart disease due to obstruction or spasm of the coronary arteries. Angina increases the risk of a heart attack but it is not a heart attack.
THE DEMANDS OF THE MYOCARDIUM ARE NOT BEING MET BY ITS BLOOD SUPPLY. The myocardium becomes hypoxic leading to chest pain
Describe the pathophysiology of angina pectoris
Reduced flow of blood to the heart.
It means depleting the myocardium of its nutrients due to
- A clot due to atherosclerosis
- A vascular spasm
Leading to heart pain and shortness of breath
Describe the difference between ‘stable’ and ‘unstable’ angina pectoris.
This is a way of classifying angina.
Stable: pain is precipitated by physical exercise and is better with rest
Unstable: Occurs randomly, even at rest. More severe and can last longer.
Name TWO characteristic signs and/or symptoms of angina pectoris.
Heavy, CONSTRICTING/gripping CHEST PAIN, radiating to arms, neck, jaw and back. EASES ON REST. More on left side but can be bilateral
DYSPNOEA – Difficulty breathing
Name the most common cause of myocardial infarction
Caused by the death of myocardial tissue due to ischaemia. Usually due to a blockage of coronary artery by a clot/ thrombus.
When areas of the heart are damaged they scar and they do not regenerate.. The heart enlarges to compensate FOR THE LOST TISSUE.
Describe specifically the pain associated with myocardial infarction.
- SEVERE CHEST PAIN described as crushing or gripping. – Central, radiating to arms, usually left jaw, neck and back
- Pain DOES NOT IMPROVE ON REST. iT can be sharp, tight, heavy, feeling or pressure
- Sweating, nausea, vomiting, pale and clammy skin, lightheaded, SOB
- Overwhelming anxiety/sense of impending doom
List TWO causes of heart failure.
Heart failure is where the heart is impaired as a pump and therefore fails to supply sufficient blood flow and backlow of fluid also occurs
- It is caused by various cardiocasular conditions such as coronary heart disease, hypertension; heart valve disease
- Linked to insulin resistance because if insulin is not able to fulfil its role of providing glucose for the cells , the cells will suffer especially cells as energy hungry as myocardial cells.
Which type of heart failure is associated with pulmonary oedema?
Left sided failure is associated with pulmonary oedema. Blood flows backward from the left atrium into the lungs. We get a build up of fluid in the lungs.
Right sided failure is associated with
- Systemic Oedema with fluid building up in the legs up ti the hips and abdomen. This is because right side backflow goes to the stomach/legs.
- Ascites – build up of fluid around the serous membrane of te abdomen
- Portal hypertension – build up of blood going back through the portal vein
- Name TWO allopathic treatments for the following:
a. Acute heart failure
b. Chronic heart failure
a. Acute heart failure
- Sitting position
- GTN sublingually
- Cardiopulmonary resuscitation – CPR
- 100 mg aspirin
b. Chronic heart failure
- Generally a cocktail of drugs; ACE INHIBITORS, beta blockers, diuretics
- Surgery
- Pacemaker
- Aerobic exercise
- Smoking cessation
- Alcohol reduction
State TWO causes of stroke.
A stroke is where something is blocking the supply of blood to an area of the brain.
(i) Most commonly it is an ISCAHEAMIC STROKE. Either a thrombus which is a fixed clot (meaning one that gets stuck) or an Embolus – a dislodged and therefore mobile clot.
(ii) Haemorrhage stroke where the blood vessel is damaged and ruptures, most commonly due to an aneurysm
List THREE characteristic signs and/or symptoms of stroke.
One sided symptoms, rapidly developing signs of cerebral dysfunction such as:
- Loss of speech
- Loss of vision
- Sudden severe headache
- Sudden weakness
- Numbness, tingling
- Confusion
- unsteadiness
Describe the main difference between a ‘stroke’ and ‘transient ischaemic attack (TIA)’.
They have similar clinical symptoms but in a TIA impaired functions resolve in less than 24 hours and symptoms last from a few minutes to a few hours.
Some people do not even know they have had them. However it is a warning sign for a stroke so needs to be taken seriously.
Define an Aneurysm
Abnormal local dilations of arteries due to weakness of the vessel wall. The diameter of a blood vessel can expand by 50% or more
Name the brain location where berry aneurysms typically occur.
Berry aneurysm is a common example of an aneurism and occurs in the centre of the Cerebrum.
Another common type of aneurism is the Abdominal Aortic Aneurysm
Define hypertension.
High blood pressure. It is a major risk factor for cardiovascular disease and cerebrovascular events.
High is defined in the UK as140/90 or higher.
Name TWO primary causes of hypertension.
Generally lifestyle and family history,
- Obesity
- Age
- Smoking
- Sedentary lifestyle
- STRESS – fight or flight response sends msg to heart to beat faster and stronger
- excess alcohol
- High table salt intake = More sodium means retaining more water which means more pressure in a closed space.
- Nutritional deficiencies eg: magnesium
Name ONE secondary cause of hypertension.
Secondary to another identifiable cause such as renal disease and diabetes.
Name TWO complications of hypertension.
- CARDIOVASCULAR EVENTS – myocardial infarction, heart failure, aneurysm
- STROKE
- CHRONIC KIDNEY DISEASE
- Vasculay dementia
- Premature death – can reduce life expectancy by 5 years
- Retinal damage
Explain the main difference between ‘valve stenosis’ and ‘valve regurgitation’.
In valve stenosis, we have VALVE NARROWING.
Fibrosis and calcification of the valve lead to obstruction to the blood flow through heart chambers. The heart compensates by enlarging, leading to HEART FAILURE.
In vale regurgitation we get VALVE BACKFLOW.
Inadequate valve closure leads to leaking. The heart hyperophies and dilates to accommodate more blood, leading to HEART FAILURE.
Define atrial fibrillation.
It is the most common arrythmia which is a disorder of the heart rate/rhythm
It is characterised by IRRGULAR RHYTHM – abnormal, fast, irregular heartbeat associated with stagnated blood in the atria and a higher risk of STROKE.
Patients may present with palpitations, breathlessness, dizziness
Using definitions, compare ‘myocardial infarction’ and ‘cardiac arrest’.
Blockage versus conduction arrest. In both cases cardiac disease is often implicated.
Myocardial infarction is also known as a heart attack. It is where there is tissue death due to lack of blood. The lack of blood is usually due to blockage of a coronary artery by a thrombus.
Cardiac arrests are not heart attacks. It is a conduction arrest when the HEART DEVELOPS AN ARRHYTHMIA CAUSING IT TO STOP
Define ‘endocarditis’.
An inflammation of the endocardium and valves. It is usually a bacterial infection.
Explain what is meant by ‘Osler’s nodes’?
Oslers nodes is a sign of endocarditis presenting as red tender spots under the skin of fingers.
Other signs of endocarditis include
- splinter haemorrhages (splinter appearance under the nail bed)
- petechiae
- DYSPNOEA and persistent cough
- NON SPECIFIC FLU LIKE SYMPTOMS
Using definitions compare ‘myocarditis’ and ‘pericarditis’.
Myocarditis is inflammation of the myocardium
Pericarditis is inflammation of the pericardium
Both are normally caused by a viral infection but could also be due to a systemic inflammatory condition such as rheumatoid arthritis
Name ONE viral cause of pericarditis.
Flu
List TWO signs and/or symptoms of pericarditis.
Both myocarditis and pericarditis have signs and symptoms of chest pain and dyspnoea. Myocarditis also sees palpitations and tachycardia.
Pericarditis also has the following signs:
CHEST PAIN: radiating to the back, relieved by sitting up and forward and made worse by lying down or breathing deeply.
DYSPNOEA: when reclining
PERICARDIAL FRICTION RUB: heard with auscultation
BREATHING IN WORSE THAN OUT: the pericardium physically attaches to the diaphragm. When breathing in and drawing the diaphragm into the abdomen you are pulling on the pericardium sac which is inflamed.
Describe ‘cardiac tamponade’ (a complication of pericarditis).
The pericardium is a serous membrane and therefore made up of teo layers with fluid in between. When the pericardium is inflamed you can get more fluid being produced putting pressure on the heart and inhibiting it from filling completely. The build up of fluid is called a cardiac tamponade.
The pericardium sac should be nice and flexible to allow the heart to pump easily. On CONSTRICTIVE pericarditis it is thickened and fibrotic
Name TWO risk factors that cause a ‘deep vein thrombosis (DVT)’ by:
a) Reducing blood flow
- Things that risk the blood becoming stagnant and pooling such as immobility and long haul flights. Pressure on vein by tumour
b) Changing blood nature
- Dehydration
- Polycythaemia - a high concentration of red blood cells in your blood.
- Sticky platelets
- Oral contraceptive pill changes blood viscosity
- smoking
List TWO signs / symptoms of DVTs.
- Limb pain
- Calf swelling
- Tenderness along vein
- Distention of superficial veins because if the blockage is in deeper veins the blood will try to find another more superficial route.
- Increased skin temperature and local redness
How is a DVT diagnosed?
- Ultrasound – to help guide us to find it
- D-Dimer test – D dimer is a protein fragment formed when a clot starts to dissolve which slowly starts to happen once it is formed.
Using definitions, compare a ‘deep vein thrombosis (DVT)’ with ‘varicose veins’.
Both are issues with the venous system.
DVT is thrombus formation almost always in the deep veins of the leg which may dislodge and cause a pulmonary embolism (lung clot)
Varicose Veins are due to incompetent vales that cause pooling of the venous blood and chronically dilated superficial veins. It is not implicated in blood clots.
Define haemorrhoids.
Dilated veins in the anal canal
List TWO causes of haemorrhoids.
- Chronic constipation
- Chronic coughing
- Hypertension
- Obesity
- Pregnancy
- Abnormal bloating and straining
List TWO characteristic signs and/or symptoms of haemorrhoids.
- BRIGHT RED BLOOD with bowel movements
- Protruding haemorrhoids
- Anal itching
Define Raynaud’s syndrome.
Intermittent attacks of ischaemia in extremities.
List ONE rheumatological cause of Raynaud’s syndrome.
Rheumatoid arthritis
List THREE characteristic signs / symptoms of Raynaud’s syndrome.
- Vasospasm (blood vessel going into spasm) followed by hyperaemia (more blood than normal going into a bodies tissues or organs)
- Pallor – from spasmed blood vessels not getting circulation
- Cyanosis – due to depletion of oxygen
- Redness – blood vessels dilate and perfuse area with lots of blood
- Pain
Heart failure - if the pump is not working you get a backflow and pooling, if valves are not working same thing
- Cardiomyopathy.
Also
- Renal disease – If damaged lose the protein albumin that retains osmotc pressure and so liquid leaks out
- Hepatic - because albumin is produced in the liver
What is ascites. List TWO causes of ascites.
Ascites refers to excessive accumulation of fluid in the peritoneum between the two layers of the serous membrane.
- LIVER CIRRHOSIS is the most common reason - in 80% of cases. Of you have a scarred liver blood can’t get through
- Malignancy of the liver, stomach, colon, pancreas, ovary
- Heart Failure – especially right sides.
List TWO signs / symptoms of ascites.
- Abdominal distension
- Nausea and suppressed appetie
- Dyspnoea because the distended stomach poushes up the diaphragm and limiting the space in the chest
