cardiovascular system Flashcards
what does the cardiovascular system contain?
the heart and a crossed system of vessels: arteries, veins and capillaries
The heart is comprised of two strong __________ ______ and two related ________. One for ____________ and one for ___________ circulation.
muscular pumps
arteries
systemic
pulmonary
what is the circulation of blood around the body necessary for? (2)
- the delivery of oxygen, nutrients and hormones to the body’s cells
- removal of waste products
How does the cardiovascular system impact homeostasis?
regulation of the cardiovascular system ensures that sufficient blood is provided to all parts or the body whether resting or exercising
how must the heart beat to sustain life?
continually?
Where is the heart located anatomically?
in the mediastinum (behind body of sternum) between 2nd and 6th ribs
How much does the hearts mass lie on the left and right?
2/3 mass left
1/3 right
Posteriorly what vertebrae does the heart rest on anatomically?
T5 to T8
where in the body do we apply pressure when performing CPR? what does this do?
lower sternum
compress the heart
What does CPR stand for?
cardio-pulmonary resuscitation
What muscle does the lower part of the heart rest on?
the diaphragm
What is the lower part of the heart called?
the apex
what in the body is the apex anchored to? (3) by what? (1)
the diaphragm
back of the sternum
the great vessels
by the pericardium
what is it called when the heart overlies its boundary (is too large)?
cariomegaly
Does the heart change shape and size as we grow?
yes
When does the heart attain adult shape?
between puberty and 25 y/o
How does the heart take the shape of the chest?
it is elongated and transverse
How much does the heart weigh in men?
310 g
How much does the heart weigh in women?
225g
What is the name of the loose sac covering the heart?
the pericardium
What is the external surface of the pericardium called?
the fibrous pericardium
What is the fibrous pericardium like? (3)
tough
loose fitting
inelastic sac
What is the internal layer of the pericardium called?
the serous pericardium
What are the two layers of the serous pericardium called?
the parietal layer
the visceral layer
What is in-between the parietal layer and the visceral layer of the serous pericardium?
pericardial fluid
What does the parietal layer of the serous pericardium line?
it lines the fibrous pericardium
what does the visceral layer of the serous pericardium adhere to?
the outside of the heart
What is the function of the coverings of the heart? (2)
protection against friction
Heart remains free to move in the lubricated, loose covering
What is the role of the fibrous pericardium? (3)
- protection from infections and physical damage
- Anchoring to surrounding structures
- prevents overfilling due to rigid nature
What are the three distinct layers that make up the heart wall from external to internal?
- epicardium
- Myocardium
- Endocardium
What is the epicardium?
the outermost layer of the heart wall
What is the epicardium also known as?
the visceral layer of the pericardium
What is the epicardium composed of?
connective tissue and fat
What does the epicardium secerete a small amount of? where?
a small amount of fluid into the pericardial cavity
What is the myocardium? what is it made of?
the middle layer and thickest part of the heart wall made up of cardiac muscle tissue
what is the muscle tissue in the myocardium responsible for?
contractions in the heart
Where is the myocardium the thickest? why?
by the left ventricle so it can pump oxygenated blood through the body.
What is the endocardium? what is it made of?
the innermost layer of the heart made up of smooth muscle and elastic fibres
what does the endocardium help to regulate?
heart contracts and a smooth surface for blood flow
What does the endocardium line?
the innermost chambers of the heart and covers the heart halves
How many main chambers of the heart are there?
4
What are the two upper chambers of the heart called?
atria/atrium
what are the two lower chambers of the heart called?
ventricles
what are the left and right chambers of the heart separated by?
an extension of the heart wall called the septum
what are the atria known as?
the receiving chambers
what is the function of the right atrium?
to receive deoxygenated blood from the veins and deliver it to the right ventricle
what is the function of the left atrium?
to receive oxygenated blood from the veins and deliver to the left ventricle
why are the atria thin walled?
because they only need to pump the blood a short distance to the corresponding ventricle
What are the auricles?
a flap located in both atria which allows for the overall blood to be expanded in each atrium
how do Auricles manage the volume of blood entering the atria?
they work like reservoirs, temporarily storing blood and help to modulate blood pressure fluctuations
What are the two types of valves in the heart?
Atrioventricular (AV) valves
Semilunar (SL) Valves
Where are the AV valves located?
at the openings between the atria and ventricles
Where are the SL valves located?
where the pulmonary artery and the aorta arise from the right and left ventricles respectively
What is the name of the left AV valve?
the mitral valve
what kind of valve is the left AV valve?
a biscupid valve because it has two flaps
What is the proper name for the flaps in the valves?
cusps
What kind of valve of the right AV valve? why?
a triscupid valve because it has 3 flaps
Where is the right AV valve located?
between the right atrium and right ventricle
The AV valves allow the blood to flow from ______ to ventricles but not back into the _____.
atria
atria
What does the ventricular pump force the valves to do? where does this send the blood?
close
into the pulmonary artery and aorta
How many semilunar valves are there?
2
What are the names of the 2 semilunar valves?
pulmonary semilunar valve
aortic semilunar valve
What is the function of the semilunar valves?
to prevent the back flow of blood from the arteries back into the ventricles
what is the skeleton of the heart made of?
a set of connected fibrous rings which support the heart valves
What does the fibrous skeleton of the heart serve as an attachment point to?
the myocardium
what kind of barrier does the skeleton of the heart provide?
an electrical barrier between the myocardium of the atrium and of the ventricles
what are the two largest veins in the body?
The superior and inferior venae cavae
In the first step of blood flow through the cardiovasular system, what happens?
the superior and inferior venae cave empty their contents into the right atrium
In the second step of blood flow, what happens to the blood that is in the right atrium?
the blood passes via the right atrioventricular valve into the right ventricle
In the third step of blood flow, what happens to the blood in the right ventricle?
it is pumped into the pulmonary artery or trunk
What is the only artery in the body that carries deoxygenated blood?
the pulmonary artery or trunk
what is the opening of pulmonary artery guarded by? what is it made of
the pulmonary valve formed by three semilunar cusps
In the fourth step of blood flow, where does the blood go after the pulmonary artery?
the pulmonary artery leaves the heart and divides into the left and right pulmonary arteries which carry the deoxygenated (venous) blood to the lungs
In the fifth step of blood flow, what happens to the blood in the lungs?
the exchange of gasses takes place CO2 is excreted and O2 is absorbed
In the sixth step of blood flow, what happens to the blood after the gasses exchange?
Two pulmonary veins from each lung carry oxygenated blood back to the left atrium
In the seventh step of blood flow, what happens to the blood when it is in the left atrium?
blood passes through the left atrioventricular valve into the left ventricle
In the eighth step of blood flow, what happens to the blood once it is in the left ventricle?
it is pumped into the aorta, the first artery of general circulation
Which artery branches off the aortic artery to supply the heart with oxygen? what do they form?
the right and left coronary arteries that form into smaller branches to alternate routes
what do the small coronary veins that supply the heart do?
drain the deoxygenated blood directly into the right atrium via the coronary sinus
When there is a clot or thrombus in the smaller branches of the arteries that supply the heart what happens?
a heart attack
What are the symptoms of a heart attack? (5)
chest pain
sweating
shortness of breath
fatigue
syncope (fainting)
What side of the heart returns oxygenated blood to the lungs?
right side
what side of the heart delivers oxygenated blood throughout the body?
left side
in the conduction system of the heart, what are the four major structures?
sinoatrial node
atrioventricular node
bundle of His
Purkinje fibres
What is the role of the sinoatrial node?
pacemaker, it initiates action potential that results in an electrical impulse that spreads through the left and right atria, causing it to contract
in the conduction system of the heart, what is the sinoatrial node?
a bundle of hundreds of cells situated in the right atrial wall near the opening of the superior vena cava
in the conduction system of the heart, what is the role Atrioventricular node?
the gatekeeper between the atria and ventricles located in the right atrium at the interatrial septum
in the conduction system of the heart, what is the atrioventricular node made of?
a small mass of special cardiac fibres
in the conduction system of the heart, What is the role bundle of His?
a collection of cells
where does bundle of his extends to?
it extends from the AV node in two branches on the sides of the inter ventricular wall
what does the bundle of His do?
carries electrical signals from the AV node to the bundle branches
what do the purkinje fibres do?
send signals to the ventricles so they rhymically contract
where are the purjinke fibres located?
they are continuous with AV bundles and attach to the apex of the heart.
what do the bundle branches do in the conduction system?
they spread the electrical signals throughout the left and right ventricles which causes the ventricles to contract
Which of the nodes in the conduction system initiates the action potential?
the sinoatrial node
Where does the action potential travel once the sinoatrial node initiates it?
it travels to the atria and then to the AV node
where does action potential go once it reaches the AV node?
down to the ventricles via the bundle of his and punjinke fibres
When there is a problem with the senatorial node, how can the heart compensate via the AV node?
the AV node can take over as a secondary pacemaker, although it is slower (bradycardia)
What is slow heart rate called?
bradycardia
When the sinoatrial node has a problem, how can the atria or ventricles compensate?
the atria or ventricles can generate their own electrical impulses to sustain rhythm however they are often less efficient
When there is a problem with the sinoatrial node, how can the nervous system compensate?
the sympathetic nervous system can increase the nervous system activity to simulate the heart and increase heart rate
when the sinoatrial node has a problem, how can medical intervention help?
a pacemaker can be used if the body cannot compensate well enough
What is systole?
a single heart contraction
What is diastole?
a single heart relaxation
what are the 5 steps of the cardiac cycle (one heartbeat)?
- atrial systole (contraction)
- Isovolumetric ventricular contraction
- Ejection
- Insovolumetric ventricular relaxation
- Passive ventricular filling
what happens in atrial systole?
the atria contracts and empties, the relaxed ventricles fill with blood
What happens in isovolumetric ventricular contraction?
the initial contraction of the ventricle and the opening of the semilunar valves, blood volume remains the same
What happens during ejection?
ventricle pressure is higher than artery pressure so blood passes through the semilunar valves
What happens during is-volumetric ventricular relaxation?
semilunar valves close and AV valves open
What happens during passive ventricular filling?
There is an increase in atrial pressure due to the influx of venous blood which causes the ventricles to fill with blood
what is blood pressure?
the force of your blood pushing against the walls of your arteries and your heart pumps it around your body
what is systolic blood pressure?
The higher number that measures the pressure in the arteries when the heart beats (ventricular systole) so the 120/
What is Diastolic pressure?
This is the lower number and measures the pressure in your arteries when your heart is resting (ventricular diastole) between beat so the /80
What is normal blood pressure?
120/80
What is hypertension blood pressure?
120-139/80-90
what is high blood pressure in hypertension stage 1?
140-159/90-99
What is high blood pressure is hypertension stage 2?
160+/100+
What is blood pressure in hypertensive crisis?
180+/110+
what is the unit measurement of blood pressure?
mmHG (millimetres of mercury)
what are three things that affect blood pressure?
cardiac output
resistance of the vessels
hormones
which nerve can affect heart rate?
the 10th cranial nerve
what are the carotid reflexes?
pressure reflexes in the neck which communicate with the brain
How do carotid reflexes affect blood pressure?
they detect a rise in blood pressure and send nerve impulses that activate the parasympathetic nervous system (calms us) so lowers BP
how does the aortic reflex affect blood pressure?
it detects a rise in BP and communicates with the brain to decrease heart rate
