Topic 2 - Cardiovascular System Flashcards
What is blood movement involved in?
delivery of oxygen and nutrients
transport of hormones
delivery of antibodies and immune cells
removal of waste product
What is the main function of the heart?
To transport oxygen
Where is the heart found (2 names possible)?
In the mediastinum or interpleural space
What is the apex and base of the heart
The apex is located at the bottom left (left ventrical) while the base is at the top right (right atrium)
What are the layers that make the heart wall?
The epicardium (Visceral layer), the myocardium (muscle) and endocardium (inner layer)
What is the thickest part of the heart composition?
The myocardium
What are the components of the pericardium?
fibrous layer, parietal layer, visceral layer
Going from the outside in, what is the order of the parts of the heart?
Fibrous layer, pariental layer, pericardial cavity, visceral layer/epicardium, myocardium and endocardium
What layer of the heart is in contact with the blood?
The endocardium
What type of tissue is the myocardium?
striated
What type of circuits does the heart pump?
The right side pumps through the pulmonary circuit
The left side pumps throught the systemic circuit
What are the thickest veins in the body?
The superior and inferior vena cava
What is the cornary artery?
The vessles that supplies oxygenated blood to the heart muscle
What part of the heart is the strongest and why?
The left ventrical because it has to pump the oxygenated blood that travels in the whole body
Explain the cyle of blood flow
- deoxygenated blood arrived in the right atrium throught the superior and inferior vena cava
- The tricuspid/right atrioventricular valve opens
- The right ventricle recieves the blood
- The pulmonary/semilunar valve opens
- The blood travels throught the pulmonary arteries
- The blood travels to the pulmonary capillaries
- The left atrium recieves the oxyganated blood throught the ventricular vein
- The mitral/ left atrioventricular/biscupid valve opens
- The left ventricle recieves the oxygenated blood
- The aortic valve opens and blood travels in the aorta or coronary artery
What is diastole?
The relaxation, filling or repolorization of the heart chambers
What is systole?
The contraction, emptying or depolorization of the heart chambers
What is systemic circulation?
provides blood to the body
What is coronary circulation?
provides blood to thw heart
When a textbook says systoli, what do they mean?
The contraction of the ventricular chambers
What is the auricles?
The visible parts of the atria
What are the interventricular sulcus?
The borders of the ventricles which contain fat and blood vessles of coronary circulation
Why are the walls of atria not as strong as the ventricals?
Its because the blood pressure is lower in the atria
Where does the coronary sinus lead?
To the right atrium (deoxygenated blood)
What is the pulmonary trunk?
It’s a part of the heart that becomes the pulmonary artery, and divides into the right and left pulmonary arteries towards each lung
How does the heart get blood for itself?
It uses the coronary system, vessels for the heart muscles itself it does not feed from the chambers
What determines the valves opening and closing?
The pressure differences between the chambers
Which valves have 3 flaps?
Tricuspid/right atrioventricular valve
Pulmonary/semilunar valve
Aortic/semilunar valve
Which valves have 2 flaps?
Mitral/bicuspid/left atrioventricular valve
What is the main purpose of the valves?
To prevent blood from going back to the previous chamber
What parts of the atrioventricular valves prevent them from bending back?
The chordae tendinae
What are the muscles connected to in the atrioventricular valves?
The papillary muscles
Which valves are open during ventricular systole?
Pulmonary/semilunar valve and aortic/semilunar valve
Which valves are closed during atrium diastole?
Tricuspid/right atrioventricular valve and mitral/left atrioventricular valve/bicuspid
What modulates the heart beat?
The nervous system and hormones
How does the appearance of cardiac muscles compared to skeletal?
They are striations but smaller and have multiple branches
How many nuclei do cardiac muscles have
One unlike skeletal which can have multiple
What are intercalated disks, and where do they occur?
They are the attachment sites between cardiac muscle cells. They occur at the Z line of the sarcomere
What structures are found in intercalated disks, and their functions?
Desmosomes (holds cells together) and gap junctions (allow ion transfer for electrical impulses)
What is the function of ATP in cardiac muscle contractions?
Allows muscle filaments to come closer and contract
T or F: cardiac muscle cells contract independently
True
What rhythm do cells follow?
The fastest one between them
What is the function of the sinoatrial (SA) node?
It’s the heart’s pacemaker and generates impulse by itself
How do cardiac muscle cells differ from skeletal muscles cells in impulse conduction?
Cardiac muscles can conduct an impulse
What is the role of ion movement across the sarcolemma?
It’s the source of electrical impulses
How does the autonomic nervous system influence cardiac muscle activity?
Sympathetic nervous system (fight or flight)
Parasympathetic nervous system (rest and digest)
What causes rapid depolarization in cardiac muscle cells?
The opening of voltage-gated fast Na+ channels
What maintains the plateau phase during cardiac action potential?
The opening of slow Ca2+ channels and closing of K+ channels
What happens during repolarization in cardiac muscle cells?
Opening of K+ channels and closing of Ca2+ channels`
What is the “domino effect” in cardiac action potentials?
When one channel opens, it triggers the opening of adjacent channels which spreads depolarization
What do the cells share in the gap junctions?
They share their cytoplasm
What are the two main parts of the cardiac cycle?
Systole and diastole
Why does the AV node delay the impulse before passing it to the ventricles?
To allow the atria to complete their systolic contraction before the ventricular systole
What is the role of Purkinje fibers in the cardiac cycle?
They transmit electrical impulses to the ventricles, causing them to contract
What are the two pathways electrical impulses can take in the heart?
Fast: SA node, AV node, Purkinje fibers
Slow: the rest
What happens to the atria while the ventricles are contracting?
The atria relaxes and fills with blood
How do pacemaker cells generate impulses without external stimulation?
They slowly leak Na+ that gradually depolarizes the cell by itself
What ion is responsible for the initial depolarization in cardiac muscle cells?
Sodium (Na+)
How are pacemaker cells different?
They can contract on their own, unlike muscle cells that react to stimuli
What happens during repolarization of a cardiac muscle cell?
Potassium (K+) exits the cell
Why do fetus bypass pulmonary circulation?
They receive oxygen from the blood of the mother
What are the names of the 2 structures to bypass pulmonary circulation?
Open foramen ovale and ductus arteriosus
What does the open foramen ovale do?
It passes oxygenated blood coming from the placenta from the right atrium to the left atrium
What does the open ductus arteriosus do?
It passes oxygenated blood from the pulmonary arteries into the aorta (so minimal blood to the lungs)
What makes the sound of the heart?
The closing of the valves
Which valves are the sound lub?
Closure of mitral and tricuspid valves (ventricular systole)
Which valves are the sound dub
Closure of semilunar valves (pulmonary and aortic) (venctricular diastole)
What is cardiac output?
the amount of blood that leaves the heart
What are the two factors that determine cardiac output?
Stroke volume: amount of blood per contraction
Heart rate: number of contractions per minute
What can be said about heart rate and SA nodes?
Heart rate depends on the rate which the SA node depolarizes
What is blood pressure determine by?
The cardiac output (CO) and systemic resistance
What is resistance when it comes to blood flow?
How easy it is for it to flow - how open and closed the vessels are
When veins are contracted, what can be said about pressure and flow?
Veins fight gravity, so contracting them reduces pressure which increases flow
When arteries are contracted, what can be said about pressure and flow?
Pressure increases, which reduces flow
What is an electrocardiograph?
It measures electrical currents
What is the P-wave?
The contraction of the atrium due to SA node triggering
What is the PQ interval?
Blood flowing into the right and left ventricles
What is the PR interval?
The delay of the AV node to allow ventricles to fill and atrium to finish their contraction
What is the R peak and S peak?
R: contraction of the left ventricle
S: contraction of the right ventricle
What is the QRS complex?
The overall depolarization of the ventricles
What is the ST segment?
The start of ventricle repolarization
What is the T wave?
Ventricular repolarization (relaxing of ventricles)
Is the blood in systemic circulation under higher or lower pressure than coronary or pulmonary circulation?
Higher due to the distance, gravity, resistance, higher blood volume
Why are the aorta and pulmonary arteries more elastic fibers?
So they can stretch as they receive high-pressure blood from ventricles
Why do veins have thinner walls?
Since their pressure is lower than arteries
Define arteries, veins and capillaries
Arteries: send blood from the heart
Veins: send blood to heart
Capillaries: material exchange with tissues
Why are the veins’ lumen diameter wider?
To accommodate the blood flow since pressure is lower
What is the function of the coronary sinus?
To collects deoxygenated blood from the heart and drains it into the right atrium.
Where does the coronary sinus deliver blood?
The right atrium
