Cardiovascular Physiology - Lecture 10 Flashcards
Vascular System(The Heart) and Respiratory System
Cardiorespiratory Systems
Hollow and Muscular. Left side behind Sternum, double pump system, and part of the autonomic N.S
The Heart
Why is the Heart a Dual-Pump
Pumps blood to lungs & body.
2 Atria
Receives blood coming back to the heart and sends it to ventricles
2 Ventricles
Lower chambers; pumps blood from heart to other organs.
Dividing Wall
Septum
Sling Shot Analogy
The Atria loads up the blood that it’s going to release into the Ventricles. Pulls back and fires
Superior and Inferior Vena Cava
Superior brings in deoxygenated blood from the brain and the inferior brings in deoxygenated blood from below the heart into the Atrium
Right Atria gets blood from Vena Cava and Left gets it from the lungs.
Role of Atria
Foramen Ovale
Small Gap between two Atria that some people have not harmful unless wide enough.
Why does the left side of the heart have more pressure?
It contains all the blood with the oxygen that’s needed to be sent throughout the entire body. So it’s going to need to push through the resistance which creates a lot of pressure.
Thin Walls
Atria
Primary Pump/delivery driver for all necessary organ systems
Role of Ventricles
Thick Walls; muscular and generate more contraction (squeeze blood out effectively)
Ventricles
It can deliver much more blood than the atria can.
Ventricles
3 muscle layers from inner to outer
Endocardium (Thin inner layer), Myocardium (Muscle Middle Layer), Epicardium (Outer protective layer)
What is the outer layer susceptible for?
Epicardium is susceptible to bacterial infection that can seep through it into Myocardium
Contracting cells are found here, and want contracting muscles to be thick and all muscular tissue. (Exercising can help build muscle thorough fibrous tissue)
Myocardium
Makes for a slippery surface for the blood to make contact with, which allows for the blood to be squeezed out.
Endocardium
Unique facts about cardiac muscle
Involuntary, contracts for your entire life, and it is not found anywhere else.
Own blood supply (coronary arteries), lots of oxygen, maximum blood flow within coronary vessels occurs when heart is relaxing
What cardiac muscles need
If the heart itself is pumping blood to other parts, it needs its own blood supply and nutrients (O2). It needs to get that from the oxygenated blood being pumped out.
Coronary Arteries
Why are some heart attacks not as bad as others
Depends on where the coronary artery gets clogged
(Left Ventricle = you’re fucked)
Which Artery carries deoxygenated blood?
Pulmonary Arteries
Which Veins carry oxygenated blood?
Pulmonary Veins
Tricuspid Valve
3 flaps, opens right atria to right ventricle
Pulmonary Valve
Opens the right ventricle to allow blood to go to lungs
Bicuspid Valve
2 flaps, allows oxygenated blood from lungs to open left atria and enter left ventricle.
Aortic Valve
Allows blood to leave left side of heart and not come back in
Chordae Tendinae
Holds the valves together; can snap.
You’re pulling the sling shot back which means you’re filling the heart with blood; it’s relaxing.
Diastole
Letting go of slingshot is the contraction; work/pressure
Systole
AV Valves open and blood flows into ventricles via suction. Low pressure and the slingshot is being pulled back.
Phase 1 of Cardiac Cycle, A.K.A. Diastole
All valves are closed, an increase in pressure and the ventricles are all full. Brief pause before release
Phase 2, A.K.A Isovolumetric Contraction Period
Contraction; letting go of slingshot. Pressure starts to go up possibly reaching 120 mmHg
Phase 3, A.K.A. Systole
After the release there’s a brief moment of relaxation where AV valves and ventricles are closed
Phase 4, A.K.A. Isovolumetric Relaxation Period
P wave
First phase of cardiac cycle where atria is filling
Q,R,S Wave
Where the ventricles are contracting/firing
T Wave
Where the ventricles are relaxing
What causes our heart rate to go up?
Sympathetic Nervous System
Parasympathetic
What causes your heart rate to go down and relax
What dictates Heart Rate?
Sympathetic and Parasympathetic
What other factors cause the heart rate to change?
Exercise, Toxins, Altitude, Heat/Cold.
Heart cells conduct electricity extremely well
Fun Fact
Primary Pacemaker that sets heart rate rhythm and generates nerve impulses to allow both atria to contract.
SA Node
What happens once the rhythm is set in the SA Node?
Heart cells will contract in atria and communicate an electrical signal to the second node
Pathway for signals to reach the ventricles; determines the contraction
AV Node
Signals gets picked up from the AV Node and sent by these down the septum
Left and Right Bundle Branches
Purkinje Fibers
Plays big role in helping ventricles contract and squeeze blood out
Sinus Tachycardia
High heart rate but normal troph’s and peaks
Bradycardia (Atrial Fibrillation)
P wave has not bump; suggest atria is not working properly
Ventricular Fibrillation
Ventricles contract irregularly without signals; doesn’t pump blood to body
Units is BPM and measured through palpation or electrical conductivity
Heart Rate
Pacemaker, energy demand, depressants, environmental temperature, availability of O2
How the heart rate is effected
Stroke Volume
It’s the amount of blood ejected out the ventricles per beat
Preload, Afterload, Contractility
Determinants of Stroke Volume
How much blood is actually filling into the ventricle before it contracts
Preload
It’s the pressure that the ventricles work against to open semilunar valves to get blood to flow out.
Afterload
Vascular resistance; the higher the resistance the higher the afterload
High afterload
Causes for high afterload
Hypertension. Makes the LV work harder to eject blood into the aorta. This can’t happen unless the ventricle generates enough pressure to overcome the pressure passed the semilunar valves. causes the arteries to rupture from all the intense work and narrow.
Anti-diuretics, lowering sodium intake and strength training
Lowers blood pressure and increases Stroke Volume
How hard the heart is squeezing when it contracts
Contractility
Total amount of blood ejected per minute; reflects the ability of heart to meet body’s need for blood flow
Cardiac Output
Q (L/min) = HR (bpm) x SV (mL)
Cardiac Output Formula
Aorta contains the highest pressure of blood which is essentially the systolic pressure of blood. That is why it’s 120mmHg around there
Systolic blood pressure
Capillaries
Where most of gas, nutrients, hormones are exchanged/delivered
Veins and Venules
Capacitance vessels; hold volume but no exchanging of nutrients
Arteries
High tolerance to pressure, elastic, surrounded by smooth muscle, 3 primary layers
Endothelium (Slippery Muscles), Sub-endothelium, Internal Elastic lamina
Tunica Interna
Tunica Media
Muscular layer right outside the Tunica Interna. External elastic lamina.
Muscular Layer of Tunica Media
What causes the arteries to contract and dilate; how blood gets everywhere around the body.
Protective layer around the vessels
Tunica Externa
Very thin and just contain an endothelium (no smooth muscle)
Capillaries
Allows for gas exchange and nutrient exchange
Endothelium cells of capillaries
Control Blood Pressure
Endothelium
Governs vasoconstriction and vasodilation via releasing chemicals
Endothelium
Capacitance (flexible) vessels
Veins
Key properties of veins
Less elastic and rigid, contains valves, and 3 primary layers
Endothelium, basement membrane
Tunica Intima (Veins)
Don’t have as much smooth muscle so doesn’t constrict as much as arteries do
Tunica Media
Tunica Externa
Key for structure, Collagen
Vasoconstriction/Vasodilation
Only achievable by arteries because of smooth muscle.
What is blood pressure?
The force that blood exerts on the walls of the vasculature
The organs involved in the regulation of BP
Brain, heart, blood vessels, kidneys
How is BP regulated?
Autonomic Nervous System
Kidney and hormones control fluid intake and excretion; alter blood volume and pressure
Blood vessels - vasodilation/constriction
How do you measure BP?
When the cuff is pumped no blood goes through the artery. The needle starts to go down when the cuff is released.
What sounds are expected to be heard when measuring Systolic and Diastolic Pressure
For Systole, once you start to hear blood flowing after the release of the cuff that is the systolic number.
For diastole, you have to listen to the swooshing sound and then a slience to get the diastolic number.
A high cardiac output can lead to high BP
The high stroke volume and the heart rate can lead to more blood being pumped, ergo increasing BP
How does blood volume affect BP?
The more blood there is the higher one’s BP becomes. This is favourable when exercising
Why does sitting down for a long period of time cause BP to drop?
Sitting down causes blood to pool in one place for quite some time which means the heart does not need to do much work.
How does Total Peripheral Resistance (TPR) affect Blood Pressure?
TPR is how well the arteries can constrict. If the TPR is high then it’s a good amount of constriction which can cause blood pressure to increase because the heart needs to work hard.
When blood pressure goes up…?
1) Brain triggers autonomic response
2) Cardiac output goes down; Vasodilation goes up; TPR goes down
3) BP goes down; return to homeostasis
When the blood pressure goes down…?
1) Foot on gas, and off brake
2) Cardiac Output goes up; Vasoconstriction/TPR goes up
3) BP goes up; return to homeostasis
Purposes of Blood
Transport, Immunity, Clotting Factors
Contents of Blood
RBC (45%)
Buffy Coat (<1%) - made of WBC and platelets
Plasma (55%) - most of the nutrients found here
90% of plasma is water
Fluid portion of blood
Plasma contents
Electrolytes, glucose, lipids, proteins, vitamins, minerals, salt, gases, hormones and other chemical messengers.
Development of Plaque in Blood Vessels
Atherosclerosis
What does atherosclerosis do?
Limits O2 flow to organs; leads to heart attack, stroke or death
What is plaque?
Made up of fat, cholesterol, calcium, and other substances found in the blood.
How does Atherosclerosis develop?
1) LDL enters into smooth muscle
2) LDL causes cholesterol to get into endothelium cells
3) Fibrous cap forms which narrows the lumen
4) Fibrous cap breaks and forms a thrombosis to block the vessel lumen.
Angina
A type of chest pain caused by reduced blood flow from narrowed lumen
What’s good about Angina
It’ll let the person know that they shouldn’t push themselves any further and should take some medications or do something to prevent it from leading to any further problems.
Thrombosis
Occlusion (blockage) of the blood vessel
Myocardial Infarction
Another name for Heart attack; caused by lack of blood flow to certain parts of heart muscle.
Symptoms of Heart Attack
Tightness, heavy squeezing pain
Pain may radiate to shoulder (mainly women)
Anxiety
Sweating or cold
Nausea & Vomiting
Shortness of breath
Dizziness, fainting or loss of consciousness
Performed prior to surgery with a view to angioplasty; provides the extent of coronary artery disease
Angiography
Why isn’t angioplasty a permanent cure
It only clears the problem in one spot and the stent only lasts for about 10 years
Coronary Graft Bypass
Take a part of the vein from a part of the body and replace the artery with it. The vein will adapt to the pressure of the blood and become an artery
Deep Vein Thrombosis
Clot that forms in large veins, usually in legs
Causes for DVT?
1) Stagnant blood from Immobility (prolonged sitting)
2) Hypercoagulability (clotting of blood faster than usual)
3) Cancer
4) Trauma to vein or leg
Thrombus and Embolus
Thrombus is a clot and Embolus is the clot breaking off and flowing through the blood
Pulmonary Embolism
Clot gets stuck in artery of lung, blocking blood flow to part of the lung
Symptoms of Pulmonary Embolism
Chest pain when taking deep breaths
Shortness of breath
Fainting
Dizziness
Sweating
Anxiety
What are the two types of Strokes
1) Bleed in the brain caused by a rupture
2) Clotting in the brain
How to tell what type of stroke someone is experiencing?
Younger person gets a bleed stroke and an older person typically gets a clot
Warning signs of a stroke?
Weakness, Trouble Speaking, Vision Problems, Headaches, Dizziness
Broken Heart Syndrome
Known as Tako-Tsubo because the broken heart looks like a lobster trap in Japan.
What happens to the heart in BHS?
The left ventricle balloons. The reason behind it is the stress and panic one feels when going through an intense situation. Lowering adrenaline rush through calming down and breathing prevents BHS
