Adult Cardio 1 (Normal anatomy and physiology of the cardiovascular system) Flashcards
What are the two purposes of the circulatory system?
-To deliver oxygen, nutrients, and other substances to all the body’s cells
-To remove the waste products of cellular metabolism
Delivery of oxygen and nutrients, as well as the removal of waste, is achieved by a complex array of tubing (___ ___) and a pump (the ___)
Blood vessels, heart
Cardiovascular function is ____ and ____, with cooperation from other systems, specifically the nervous system and endocrine system
Continuous; automatic
Nutrients and oxygen are supplied by the ____ and ____ systems
Digestive; respiratory
Gaseous waste is removed by the ____
Lungs
Other waste products are removed by the ___ and ___
Liver and kidneys
The heart structures are categorized by what 3 functions?
-Structures that support the circulation of pulmonary and systemic blood flow through the heart
-Structures that maintain the cells of the heart
-Structures that stimulate and control the heart action
What structures support the circulation of pulmonary and systemic blood flow through the heart?
-Heart wall and fibrous skeleton
-Valves
-Great vessels
What structures maintain the cells of the heart?
-Vessels of the coronary circulation
-Lymphatic vessels of the heart
What structures stimulate and control the heart action?
Nerves and specialized muscle cells that direct rhythmic contraction and relaxation of heart muscles
The heart is shaped as a quadrangular pyramid and is orientated as if the pyramid has fallen onto one of its sides so that its base faces the ___ ___ ___ and its apex is pointed towards the ___ ____ ____
-Posterior thoracic wall
-Anterior thoracic wall
The anterior surface of the heart contains almost all of the ___ ___
Right ventricle
The inferior surface of the heart is also known as the ____ surface
Diaphragmatic
The inferior (diaphragmatic) surface of the heart contains…
Mostly right ventricle and some of the left ventricle
The right lateral surface of the contains the ___ ___
Right atrium
The left lateral surface of the heart contains…
The left ventricle and a small part of the left atrium
The posterior surface of the heart contains…
The left ventricle and most of the left atrium
The broad end of the heart (base) is _____, while the tip (apex) is ____
Superior; inferior
Since the heart sits on the diaphragm, it can cause symptoms like ___ and ___
Nausea/vomiting
The heart is rotated ___ and ___
Laterally, inferiorly
The apex of the heart lies under the ___ ___
Left nipple
Most of the left ventricle is back under the ___ and towards the ___
Arm, back
The ____ is the membrane that separates the right and left ventricle
Septum
The ____ is the outermost layer of the heart
Epicardium
The ____ is the middle layer of the heart
Myocardium
The ____ is the inner surface of the heart
Endocardium
The ___ ____ ____ prevents friction from the heart beating (acts as lubricant)
Pericardial cavity fluid
With too much pericardial cavity fluid, the heart would not be able to ____
Pump
The ____ layer encapsulates the heart in the chest and separates it from the lungs
Parietal
Layers of the heart (starting with the outermost layer):
-Fibrous pericardium
-Parietal layer of pericardium
-Pericardial cavity
-Epicardium
-Myocardium
-Endocardium
-Heart chamber
The heart wall contains what layers?
-Epicardium
-Myocardium
-Endocardium
A heart contains how many chambers?
4 (2 upper, 2 lower)
The upper chambers contain…
-Right atrium
-Left atrium
The role of the upper chambers is to…
Recieve incoming blood
The lower chambers are more muscular and contain…
-Right ventricle
-Left ventricle
The role of the lower chambers is to…
Pump blood out of the heart
The role of the right atrium:
Receives oxygen-poor blood from the body and pumps it to the right ventricle
The role of the right ventricle:
Pumps oxygen-poor blood to the lungs
The role of the left atrium:
Receives oxygen-rich blood from the lungs and pumps it to the left ventricle
The role of the left ventricle:
Pump oxygen-rich blood to the body
The ___ ventricle is thicker than the ____
Left; right
The left ventricle is a ___-___ system
High-pressure
The left ventricle has ____ contractions
Concentric (more round)
The right ventricle is a ___-___ system
Lower-pressure
The right ventricle has ____ contractions
Bellows
The ____ ventricle has more workload because it has to pump blood further/harder
Left
The left ventricle is more ____, so it will generate a strong pressure even with little effort
Circular
The right ventricle is more ____ and causes a bellow contraction
Angular
The left ventricle pumps blood to the rest of the body, so it needs more ____
Pressure
If you want blood to pump from left to right, we need to have more pressure on the ____
Left
Blood flows in circulation not only because of the beating of the heart, but because it is a continuous cycle of ___ ____ on one side and ___ ___ on the other side
High pressure; low pressure
Heart ____ are parts of your heart that act like doors by opening and closing to let blood flow from one area of the heart to another
Valves
Valves help ensure that blood moves at the right ___ and in the correct ____
Time; direction
What are the four valves of the heart?
-Aortic valve
-Mitral valve
-Pulmonic valve
-Tricuspid valve
Step 1 in the route of blood:
Blood that needs oxygen flows from your body into the right atrium
Step 2 in the route of blood:
The blood flows through the tricuspid valve to the right ventricle
Step 3 in the route of blood:
The right ventricle pumps the blood through the pulmonary valve and into your lungs, where it picks up oxygen
Step 4 in the route of blood:
The oxygen-rich blood then flows to the left atrium
Step 5 in the route of blood:
The heart pumps through the mitral valve into the left ventricle
Step 6 in the route of blood (last step)
From the left ventricle, the blood flows through the aortic valve to the rest of your body
The Tricuspid valve has 3 leaflets, which are:
-Anterior
-Posterior
-Septal
The tricuspid valve and its leaflets allow blood to flow from the ___ ___ to the ___ ___
Right atrium to right ventricle
The tricuspid valve also prevents blood from flowing ____
Backward
What are the three leaflets of the pulmonary valve?
-Right
-Left
-Anterior
The pulmonic valve and its leaflets allow blood to pump from the ___ ____ to the ___ ____
Right ventricle; pulmonic artery
The pulmonic artery leads to the ____ where the blood picks up oxygen
Lungs
The pulmonic valve also prevents blood from flowing ____
Backward
What are the two leaflets of the mitral valve?
-Anterior
-Posterior
The mitral valve and its leaflets allow blood to flow from the ____ into the ___ ___
Lungs; left atrium
The mitral valve and its leaflets also prevent blood from flowing ___
Backward
What are the three leaflets of the aortic valve?
-Right
-Left
-Posterior
The aortic valve and its leaflets open to let blood flow from your heart’s ___ ____ to the ___
Left ventricle; aorta
The ____ is the largest blood vessel in your body
Aorta
The aorta brings ____ ____ from your heart to the rest of the body
Oxygenated blood
The aortic valve prevents blood from flowing ___
Backward
When the heart is enlarged, the muscles are going to stretch and pull the leaflets open which causes blood to squeeze back and cause a ____ by moving backward
Leak
Both the left coronary artery and the right coronary artery start at the ___ ____
Aortic arch
The right coronary artery supplies blood to the ___ ___ and ___ ___
Right atrium and right ventricle
Branches of the right coronary artery supply the ____ node and the ____ node
-Sinoatrial (SA)
-Atrioventricular (AV)
The sinoatrial and atrioventricular nodes send ___ ___ through your heart
Electrical signals
Branches of the right coronary artery also deliver blood to 1/3 of the _____ ____, which is the wall between the heart’s 2 chambers
Interventricular septum
The left coronary artery supplies blood to your ___ ___ and ___ ____
Left atrium and left ventricle
The left coronary artery is where ___ ___ arrives from your lungs before your heart pumps it out to the rest of the body
Oxygenated blood
Branches of the left coronary artery supply blood to the other 2/3 of your ___ ___
Intraventricular septum
The coronary veins return deoxygenated blood from the myocardium back to the ____ ____
Right atrium
Coronary venous anatomy is highly variable, but it is generally comprised of what three groups?
-Cardiac veins
-Anterior cardiac veins
-Venae cordis minimae
Cardiac veins drain into the ___ ___
Coronary sinus
Cardiac veins that drain into the coronary sinus include…
-Great cardiac vein
-Middle cardiac vein
-Small cardiac vein
-Posterior vein of the left ventricle
-Vein of Marshall
Anterior cardiac veins drain directly into the ___ ___
Right atrium
The venae cordis minimae are the smallest cardiac veins and they drain directly into all four chambers, but are more frequent int the ___ ___
Right atrium
Takeoff of coronary arteries is immediately beyond the ___ ___ in the aorta
Aortic valve
The ___ ___ has minimal blood flow during systole (when aortic valve leaflets open)
Coronary Ostia
The coronary artery fills with blood during ____
Diastole
___ ____ peaks during diastole
Coronary circulation
____ occurs when the heart contracts to pump blood out to the rest of the body
Systole
Diastole is when the heart relaxes after ____ and blood comes back to the heart to refill it before it contracts again
Contraction
Coronary blood flow is approximately ____ cc/min (4-5% of total CO)
225
Coronary blood flow ____ in systole
Decreases
Coronary blood flow ____ in diastole
Increases
Coronary blood flow is greatest during ___ ___
Early diastole
If diastolic time is shortened, coronary flow is ____
Decreased
Coronary artery blood flow moves from ____ to ____ surfaces
Epicardial to endocardial
Epicardial coronary artery blood flow is impinged by ___ ___, affecting subendocardial vessels the greatest
Cardiac contraction
____ is where the most work happens within the heart
Systole
We want blood to flow from the ___ down to the ___
Myocardium, epicardium
Blood flows on the surface first, and then through the arteries to get to the epicardium, meaning that the epicardium is ____ last
Oxygenated
If we do not have enough oxygen, the epicardium will get oxygenated before the ____, leaving it with no oxygen
Endocardium
In ____, there is low pressure with maximum blood flow in intra-myocardial vessels
Diastole
In ____, there is a circumferential squeeze around intra-myocardial vessels
Systole
Tachycardia is harmful because you are spending more time in ___
Systole
___ ____ are given to those with tachycardia to slow heart rate
Beta-blockers
What are the two main mechanisms in which coronary blood flow is controlled?
- Coronary supply
- Myocardial demand
Coronary supply is regulated almost exactly in proportion to the need of ___ ____ (supply=demand)
Cardiac musculature
Even in a resting state, __-__% of oxygen is extracted from blood in coronary circulation
65-75%
To increase oxygen availability, blood flow must ___
Increase
What must happen to increase delivery of oxygen?
-Increase heart rate
or
-Increase arterial diameter
or both
Possible mechanisms for coronary artery dilation in response to increased oxygen needs:
-Release of adenosine by myocardial cells
-Release of other vasodilator substances (K+, H+, CO2, bradykinin, PGE)
-Relaxation of vessel walls in response to oxygen deficiency
-Nervous control of coronary blood flow
The parasympathetic nervous system has ___ inflence on coronary blood flow
Negligible
The sympathetic nervous system can heavily influence coronary blood flow by causing what two things?
-Epicardial vessel preponderance of alpha receptors
-Intramuscular vessel preponderance of beta receptors
___ ___ is determined more by intraventricular pressure than by work of the heart
Myocardial demand
____ ____ is not as closely related to the work of the heart as it is to the increase in pressure
Oxygen consumption
___ ____ ____ is the primary determinant of oxygen consumptions
Peak muscle tension
Heart chamber ____ (even in diastole) results in increased muscle tension
Dilation
La Place’s Law states that wall tension is ____ related to the product of intraventricular pressure and internal radius, and ____ related to wall thickness
Directly, inversely
La Place’s Law Formula:
(Pressure x radium)/(2 x wall thickness)
A network of specialized muscle cells found in the heart’s walls send signals to the rest of the heart to cause contraction; this group of muscle cells is known as the ___ ____ ____
Cardiac conduction system
What are the 5 main parts of the cardiac conduction system?
-SA node
-AV node
-Bundle of HIS
-Bundle branches
-Purkinje fibers
Within the cardiac conduction system, the ___ ___ starts the sequence by causing the atrial muscle to contract
SA Node
Since the SA node starts the contraction, many times it is referred to as the ___ ___
Anatomical pacemaker
After the SA node causes contraction of the atrial muscles, where does the signal continue to travel?
-To the AV node
-Through the bundle of HIS
-Down the bundle branches
-Through the Perkinje fibers (causing the ventricles to contract)
Cardiac myocytes are composed of myofibrils that contain ____
Myofilaments
Myofibrils have distinct, repeating units called ____ which represent the basic contractile units of the myocyte
Sarcomeres
The sarcomere is defined as the region of microfilament structures between two ___-___
Z-lines
The sarcomere is composed of thick and thin filaments called ___ and ___
Actin and myosin
Chemical and physical interactions between the actin and myosin cause the sarcomere length to shorten, and therefore the myocyte to ____ during the process of excitation-contraction coupling
Contract
The interactions between actin and myosin serve as the basis for the ___ ___ theory of muscle contraction
Sliding filament
Electricity in the heart comes from what three things?
-Sodium
-Potassium
-Polarity (more sodium outside, more potassium inside)
The inside of the cell is negatively charged so the membrane has ___ ____
Action potential
What two ions mainly exist in the extracellular space (outside of the cells)?
-Sodium
-Calcium
When the membrane of a cell becomes permeable, sodium and calcium rush into the cell and give it a large ____ charge (potassium has the opposite effect)
Positive
Once the ventricle is stimulated, there is an impulse that would cause a ___-___ ion channel to open and sodium to rush in
Voltage-gated
When sodium rushes in, it ____ the cell and causes a positive charge inside the cell and a negative charge on the outside of the cell
Depolarizes
____ recognizes the change in polarity of the cell (caused by sodium) and will come into the cell and send potassium out to bring the membrane potential/polaity closer to resting (negative)
Calcium
The calcium controls everything and is a ____
Messenger
Once inside the cell, calcium goes to the ____ ____ to tell it to release its stores of calcium which causes lots of calcium in the cytoplasm
Sarcoplasmic reticulum
Calcium acts on actin as a messenger which opens the gate and causes the ____ and ____ to get shorter
Myosin, sarcomere
Once the sarcomere has contracted, the sarcoplasmic reticulum basically collects the ____ back
Calcium
The cardiac muscle tissue is also known as the ____
Myocardium
When a cardiac muscle cell contracts, the ___ filaments pulls the ____ filament toward each other, causing the cell to shrink
Myosin; actin
A single myosin filament connects to ___ actin filaments on either side; this unit is what makes up a sarcomere
2
Intercalated discs connect cardiac muscle cells and ____ ____ relay electrical impulses from one cardiac muscle cell to another
Gap junctions
____ are structures present within intercalated discs that hold cardiac muscle fibers together
Desmosomes
The ____ is the cell membrane of muscle cells and is made up of longitudinal units
Sarcolemma
___ ___ are extensions of cell membranes into cells and allow for the transmission of action potential into the depths of cells
Transverse tubules
The ___ ____ is located around the myofibrils; when an action potential is transmitted through the transverse tubules, this releases its stored calcium which activates actin and myosin
Sarcoplasmic reticulum
Actin and myosin filaments are composed of ____ protein molecules
Polymerized
Actin and myosin lie __ by ___, with approximately 1500 myosin and 3000 actin filaments per myofibril
Side by side
Actin filaments are very ___
Thin
Myosin filaments are thicker and contain ___ ___ ___
Hinged cross bridges
Actin and myosin partially interdigitate, causes the myofibril to have alternate ___ and ___ bands
Light and dark
Actin filaments are attached to a ___ ___/___
Z membrane/disk
Z membranes pass from myofibril to myofibril, attaching them to each other and forming __ ___
Z bands
The ___ filaments reside between the actin filaments
Myosin
The potion of the myofibril that lies between two successive Z bands is a ___
Sarcomere
In the relaxed state, the ends of the actin filaments from two successive Z membranes barely ____, while at the same time completely covering the myosin filaments
Overlap
In the contracted state, the actin filaments are pulled inward along the ___ ___ so that they overlap each other to a major extent, and the Z membranes are pulled inward until they touch the myosin filaments
Myosin filaments
Each myosin filament is a coil of 2 chains wrapped around each other; at the end of each chain is a ___ ___ that looks like a two-headed golf club (called the head)
Globular region
Myosin molecules are combined into ____, which are stalks of myosin from which the heads protrude at regular intervals
Filaments
In the resting muscle, the myosin binding sites are covered by ____ and ____
Troponin and tropomyosin
When the action potential reaches the muscle cell, ___ ___ carry the message deep into the sarcoplasm where the sarcoplasmic reticulum releases calcium
Transverse tubules
Once calcium is released, it binds to ____ which makes tropomyosin move to uncover the myosin binding site
Troponin
Then, the myosin heads bind to actin filaments to create ___-___ between the myosin and actin binding sites to cause contraction
Cross bridges
The combined effects of actin-myosin interactions within all of the myofibrils produce muscle ____
Contraction
5 steps of actin-myosin interactions leading to contraction:
-Calcium binds to troponin, leading to a conformational change that displaces tropomyosin from the actin binding sites
-Crossbridge formation occurs with ATP hydrolyzed into ADP+P
-Power stroke moves actin filament toward the center of the sarcomere; ADP+P are now released from the myosin heads
-Actin released with ATP binding to myosin. Myosin heads cocked back into firing position, ready to make crossbridges further downstream
-The cycle continues until calcium levels decrease, allowing calcium to dissociate from troponin. Tropomyosin returns to original conformation that blocks actin binding site.
During contraction, there is progressively ___ overlap of the actin and myosin which causes the dark bands tp get darker
More
____ is the main regulator of contraction
Calcium
How does calcium initiate muscle contraction?
-Calcium enters the cell and goes to the sarcoplasmic reticulum
-Calcium-induced calcium release from sarcoplasmic reticulum
-Calcium binds to troponin to cause tropomyosin to move away from actin binding site
How does calcium cause muscle relaxation?
-Cessation of inward flow of calcium
-Uptake and storage of calcium into the sarcoplasmic reticulum (active transport)
-Drop in intracellular calcium
The composition of ___ and ____ ions in myocardial cells is different
Intracellular, extracellular
At rest, the internal cellular environment is more ____ charged as compared to the external environment
Negatively
Substances can travel through the cell membrane by what two methods?
-Assisted diffusion (mediated transport)
-Active transport
With assisted diffusion, you can have either ___ or __ __ ___ __
Pores, voltage-gated ion channels
What are two examples of active transport?
-Sodium potassium pump
-Sodium calcium pump
At baseline, the sodium-potassium pump maintains a ___ charge inside the myocardial cell
Negative
The ____ of the membrane to the ions determines the electrical environment of the cell
Permeability
At rest, the membrane integrity is such that only a slight movement of the ions is permitted, so the relative ___ charge of the internal environment is preserved
Negative
Upon stimulation, the voltage-gated pores on the cell membrane are activated such that the permeability to ___ and ___ are changed; this causes assisted-diffusion to occur, resulting in elctropositivity in the cell
Sodium and potassium
Next, the ___ ___ ___ will be activated
Active transport pumps
Upon stimulation, the influx of sodium through the inward sodium channels reverses the ____ of the cell
Polarity
The reverse polarity triggers the influx of potassium through the outward potassium channels, which ____ polarity
Restores
What are the 4 phases of an action potential?
-Depolarization
-Plateau
-Final Repolarization
-Return to RMP
What happens during the depolarization phase of an action potential?
-Sodium influx
-Cell interior becomes more positive
-At threshold, fast channels open causing a rush of sodium inward with briefly allows the cell to become more positive than the outside
What happens during the plateau phase of an action potential?
-Rapid influx of sodium is terminated
-Sodium-potassium and sodium-calcium pumps become active
-Calcium entering the cell stimulates further release of calcium from sarcoplasmic reticulum causing contraction
What happens during the final repolarization phase of an action potential?
-Preventing further inflow of sodium and calcium
-Continues potassium efflux out of the cell
-Intracellular environment becomes more negative
-Reestablish resting membrane potential
What happens during the 4th and final phase of an action potential?
-Final cleanup of sodium by the sodium-potassium pump
-Intracellular calcium restored by active transport to the sarcoplasmic reticulum (needs magnesium)
What are the 4 steps of signal propagation?
- Sinus node impulse
- Impulse passes through atrioventricular node
- Ventricular impulses
- Recovery
The ____ period is the period following depolarization during which no ew cardiac action potential can be initiated by a stimulus
Refractory
The ____ (absolute) refractory period corresponds to the time needed for the reopening of channels that permit sodium and calcium influx (phase 0 through half of phase 3)
Effective
The ____ refractory period occurs near the end of repolarization (following the effective refractory period); during this time, the membrane can be depolarized again, but only by a greater than normal stimulus
Relative
The phases of depolarization and repolarization occur somewhat differently in the ___ and ____ nodes; this allows these cells to generate action potentials independently and automatically
SA and AV
Depolarization begins with a less ___ resting membrane potential, then proceeds to a slow upstroke (Phase 0) and usually lack a plateau phase (phase 2)
Negative
There is also a ___ ___ ___ mediated by calcium (transient and long-lasting channels) and sodium ions flowing through “slow channels” of the cell membrane are responsible for the action potential of the SA and AV nodes
Slow inward current
A take home message is that cardiac output is the result of the synchrony between ___, ____, and ____ events of the heart
Cellular, electrical, mechanical
Stroke volume is governed by what two things?
-Entropy
-Preload
At a heart rate of 75 BMP, ___ seconds are spent in systole and ___ second in diastole for each minute
23; 37
____ time is constant, therefore as heart rate increases, ____ decreases
Systolic; diastolic
At heart rate of 120 BMP, there is ___ seconds spent in systole and ____ seconds spent in diastole
36; 24
____ compromises diastolic time and reduces vascular circulation
Tachycardia
___ ____ is the amount of blood ejected by the heart per beat (mL)
Stroke volume
___ ___ is the total volume of blood ejected per minute (L/min)
Cardiac output
___ ___ is the amount of blood ejected in relation to the total amount available (%)
Ejection fraction
___ ____ explains how cardiac output is adjusted for body surface area (L/min/m^2)
Cardiac index
Formula for calculating cardiac output:
CO= stroke volume x heart rate
____ is the volume of blood in ventricles at the end of diastole (end diastolic pressure)
Preload
What conditions can increase preload?
-Hypervolemia
-Regurgitation of cardiac valves
-Heart failure
____ is the resistance that the left ventricle must overcome to circulate blood
Afterload
What conditions may increase afterload?
-Hypertension
-Vasoconstriction
An increased afterload causes an increased ___ ___
Cardiac workload
Ventricular end-diastolic volume imposes stretch on the ____; the relationship between the length and tension of this indicates that when there is the right amount of stretch (not overstretched or understretched), there is the highest contractile strength
Sarcomeres
Circulatory blood flow is ____ related to pressure and ____ related to resistance
Directly; indirectly
Resistance is ____ proportional to fluid viscosity and length of the circuit and ___ proportional to vessel diameter
Directly; indirectly
Formula for calculating volume flowrate:
F= (P1-P2)/R
