Heart Flashcards
missing sumilinear valves, p 694-95
What is cardiology?
Study of the cardiovascular system
What is the apex of the heart?
Bottom point of the heart
formed by the ventricles
What is the base of the heart?
Broad superior surface
Formed by the artria
What are ventricles
Muscular chambers of the heart that eject blood
What are atria
Collecting chambers of the heart that contract to fill the ventricles
What directions arteries & veins bring blood?
veins bring blood towards the heart arterys away from the heart
Non oxygenated or deoxygenated
What do valves do?
Vavles prevent back flow
How do valves function
Open and close in response to change in pressure
Keeps up blood pressure and
What type of circulation does the left and right sides of the heart have?
Right is pulnanory circulation and left is systemic
Systemic functions under higher pressure
What do artiums recieve blood from
Receive blood from the veins
What are the sending chambers
Valves
What are the recieving chambers
Atrias
How many time does the heart beat
Hearts beats about 100,00 times every day or about 35 million beats
What do each side of the heart pump to?
Left side: pumps to systemic circuit
Right side: pumps to pulmonary circuit
SIze of the average heart
5 x 3.5 inches
Average mass of a male and female heart
F: 250 g
M: 300 g
Firbous pericardium function
Protection and prevents overfillings
protector/anchor
What lines the innner fibrous pericardium
Serious pericardium
What is deeper to the serious pericardium to the fibrous pericardium
visceral pericardiuum (epicardium)
What’s deeper to the pericardiums
pericardial cavity
What is deeper to the pericardial cavity and what is its parts
- Epicardium
What sre myocardium
- Cardiac muscle that is
a. Involuntary
b. Branched cells
I. intercalated disks
II. Gap junction desmosomes
What does the right atrium recieve blood from?
3 answers (they all do)
- Superior vena cava
- Inferior vena cava
- Coronary Sinus
Describe the walls of the right atrium
Posterior: Smooth
Anterior: rough with pectinate muscles that extends into the auricle
How are the left and right atriums divided
By a thin partition called interatrial septum
Oval depression in septum called fossa ovalis
The fossa ovais is a remnant of foramon ovale
From where does the blood leave the right atrium?
Through the Triuspid valve
What do the fossa ovalis and the ductus arteriosus bypass
Bypasses the pulmamory circuits
During fetal developement
How does the foramon ovalis become the fossa ovalis
The Foramon which is simply a hole closes and tissue forms during fetal developement causing it to become the fossa ovalis
Where is the trabeaculae carneae
In the right ventricle
What part of the heart does the right ventricle form
The anterior surface of it
What divides the right and left ventricle
The interventricular septum
Where does the right ventricle send blood
Blood is ejected to the pulmamaory valve to the pulmary trunk
Will reach the lungs to have gas exchange
From where does the left ventricle recieve blood
The lungs
through the 4 pulmaamory veins
Where does blood reach the left ventricle
The left atruium
through the biscuspid valve
What kind of muscle are the ventricles
They are made of papillary muscles
Share similar internal structures
Where does the left ventricle eject blood?
To the aorta
Which ventricle is thicker than the other
The left is the thickest
because it needs to pump blood to the rest of the body
Do the R & L ventricle pump more blood than the other
Right and left ventrucle pump the same volume of blood with each beat
What are the functions of the valves
Prevent backflow
Location of the atriomricular valves
between the atria and ventricles
chordae tendineae to papillary muscles
Names of the L & R of the atriomricular valves
Right: triscupid valve
Left: Bicuspid or mitral valve
Function of the coronary circulation
Blood supply to the heart
Function of the left coronary artery
runs toward the left side of the heart
divides into anteriro interventricular artery
Supplies blood to interventricular septum and anterior walls of both ventricles
Function of the right coronary artery
Runs toward right side of the heart
What are cardiac ells connected to
Intercalated discs which have
What types of myocytes does the heart have
- Pacemaker cells
- Contractile cells
What is paceaker potential?
iniatiate action potentials that spreads throughout the heart to triggger rythmic contractions
How does the heart contract
As a unit
What do pacemaker cell’s function
To spontanious depolarize and spread it in a wave across the mycardium from cell to cell
1st step pacemaker potential
Depolarization slows due to the Na+ channels open and K+ channels closing
The memebrane potential is never a flat line
2nd step pacemaker potential
The action potenital begins as the pacemaker potential reaches threshold
Depolarization is due to Ca+ influx through Ca+ channels
3rd step pacemaker potential
Ca+ channels inactivate and K+ channels opens which will bring the membrane potential back to the most negative voltge
This allows K+ efllux
Depolarization cause
Na+
During the pllateau phase what opens
Ca+ channels open
leads to loge absolute refractory period
Repolarization cause
K+
Why do heart cells stay depolarized for longer periods of time
They are able to contract for longer and an asbolute refactory period
During open Ca+ channels
What do longer periods of depolariztion of heart cells help with
Prevents the heart from tetiny
Avoide abnormal heart rythums which will kill the pacient
Where does excitation start
In the Sa node
90-100 AP per min
Where does escitation reach after the SA node
Arrives at the AV node located in the interatrial septum, and stops for 1/10 of a second
40-50 AP per min
When cells depolarize what happens
They contract
Where does the AP reach after the AV node
AV bundle
2-40 AP per min
After the AV bundle where does the AP reach
Enters the right and left bundle branches traveling upward
In the interventricular septum
How do electrocaridgraphy record AP
Transmissions through cardiac conduction system
What is the final destination of the AP after the bundle branches
AP arrive at the Purkinje fibers contracting vetricurular myocardium from apex up
ejects blood through the semilunar valves
For ECG recordings what do P waves represent
Atrial depolarization
For ECG recordings what do QRS complex represent
Ventricular depolarization
Oneset of ventricular contraction
For ECG recordings what do T waves represent
Ventricular repolarization
Why does atrial repolarization usually not visible
Masked by larger QRS complexes
What is Systole and Diastole
S: Contraction
D: Relaxation
What is the resting heart rate
75 beats per min
0.8 seconds between each beat
When the pressure in the right ventricle exceeds the aorta what opens?
The Semilunar valves open
Close when the pressure in the aorta is more than the left ventricle
end diastolic volume
The maximum amount of blood in the ventricles before they contract
S1 & S2
1: Luv
2: Dub
It’s the sound of the heart / AV valves shutting
This is not a question just formula for stroke volume
EDV-ESV = SV
end diastic volume - end systolic volume = stroke volume
120ml - 50ml = 70 mls
Example of the equation (Normal heart conditions)
What is end systolic volume
Blood leftover in the ventricles after they contract
When & Where do AV valves open
The AV valves open between the ventricles when they relax
Via. the viva cavas
What is stroke volume
Amount of blood exected per heart beat
What is the formula for caridac output
Amount of blood pumped per minute
Stroke Volume X Heart Rate
What is preload
A degree of strech of ventricles before contracting
Stretch more = contract harder
(Related to Preload)
What is Frank-Starling Law of the heart
The greater the strech the greater the contraction
What is contractility
Forcefulness of contraction of individual vibers
Glucagon, thyroxine, epinephrine, and greater Ca2+ influx all increase contraction
Wht is Afterload
Pressure that must be exceded before ejection begins
