Heart + Circulatory System Flashcards
How many chambers does the heart have and what are they?
4 chambers
2 upper (Atria) and 2 lower (Ventricles)
What 3 parts does the Cardiovascular System consist of
Heart
Circulation - blood vessels
Blood
How many times does the heart b/day
100,000 b/day
What is the location and difference between the foreman ovale and the fossa ovalis?
The upper chambers. The foreman ovals exists until the first breath or for the first 24 hours of life.
It then becomes the fossa ovalis.
How many liters of blood does the heart pump per day
3784 Liters of blood
How are the Atria seperated?
The interatrial septum.
How many miles of blood vessels per day
60,000 miles of vessels
Where are the auricles located and what is their purpose?
They are part of and above the Atria and they allow for additional expansion.
How does oxygenated blood operate regarding the heart
O2 is transported through the heart/aorta > into the rest of the body
Where are the pectinate muscles located and what is their function?
It is on the outer surface of the Atria and is used for contraction.
How does deoxygenated blood operate regarding the heart
CO2 travels through the SVC, into the pulmonary trunk, which then is released into the lungs
Heart location
Anterior to vertebral column
Posterior to sternum
1/3 is to the right of midline
2/3 left of midline
Found within the Mediastinum (area between lungs)
Where does the right atria recieve blood from and what kind of blood is it?
From the body and heart wall. The blood is low in O2 and high in Co2.
Heart size
340g=11oz
12-14cm=5in long
Which structures does the right Atria get blood from and where do those structures get that blood from?
Superior Vena Cava (all regions above the axillar (armpit))
Inferior Vena Cava (all regions lower than the axilla (armpit))
Coronary Sinus (from the myocardum)
Where does the Heart sit in the thoracic cavity
Right side:
Rib 2
Base of heart
Left side:
Rib 5-6 intercostal space
Apex of heart - midclavicular line
PMI - point of maximal intensity
Where does the left Atria get its blood, by which structure does that give said blood, and what kind of blood is it?
It receives blood from the lungs, via the pulmonary veins, and the blood is O2 rich and Co2 poor.
What is Cardiomegaly disease
Enlargement of heart - extends beyond parameters
How are the ventricles separated from each and the atria?
Interventricular septum; atrioventricular valves.
Where do the ventricles receive blood from?
The atria.
Where are the papillary muscles found, where are they attached and how, and what is there purpose?
They are located in the ventricles.
They are attached to the valves by chordae tendineae.
They prevent regurgitation (blood backflow into atria)
2 layered Protective coverings of the heart
- Fibrous Pericardium
- Serous Pericardium
Where is trabeculae carneae found and what is its purpose?
It is found at the ends of coordinate tendoneae and is for the strength of contraction of the ventricles wall.
Location and function of the Fibrous Pericardium
Outermost layer of heart
No elasticity
Prevents heart from over filling
Where do you find the atrioventricukar groove and the interventricular sulcus?
AV groove: between the atrium/ventricles
IV Sulcus: by the Great coronary vein and the Ant. IV Artery.
What kind of blood is recieved by the right ventricles ND how does it relieve it?
O2 poor Co2 rich blood by way of the tricuspid valve
What is a Cardiac Tamponade
Fluid filling sac/bag around heart, preventing full contraction
How does the right ventricles send blood out?
Through the pulmonary semilunar valve to the pulmonary trunk.
Serous Pericardium includes?
Simple squamous epi
Serous membrane
Serous fluid - lubricant/free movement
What kind of blood does the left ventricles receive and where does it get the blood?
O2 rich/ Co2 poor blood from the Left atrium via bicuspid valve.
Where does the blood from the left ventricles get sent?
To the aorta by way of the aortic semilunar valve.
What layers are within the Serous Pericardium outer to inner layer
Parietal layer
Pericardial cavity
Visceral layer
Where does the aortic arch and the pulmonary trunk send blood to?
The body and the lungs respectively.
Wall of the heart contains what 3 layers
Epicardium - visceral layer of serous pericardium
Myocardium - Cardiac Muscle
Endocardium - Lines all inner surfaces of heart & valves
What is the percentage breakdown of the myocardium?
1% Intrinsic conduction system (ICS) and 99% the contractile tissue.
Functional Syncytium is defined as
a group of cells that work together as a single unit
What similar qualities does the Myocardium have to skeletal muscle
Similar to skeletal muscle - actin/myosin
What are the 3 key features of the ICS?
Unstable resting membrane potential (leaks Na+)
Does not need outside stimulation
Is self-depolorizing (self excititory) resulting in pacemaker potential
Myocardium differences from skeletal muscle
Minimum Sarcoplasmic Reticulum
2 sources of Ca
Chordae Tendineae prevents what
Prolapse of the AV valves - Regurgitation
What are the 2 key features in the Contractile tissue?
Receives stimulation from the ICS
Stable resting membrane
Trabeculae Carneae provides?
Strength for muscle contraction
What happens in ventricular Systole?
The pressure is higher - contraction
AV valves close
—>S1 heart sound aka LUBB
SL valves open
What happens in ventricular Diastole?
The pressure is lower - relaxation
Av valves open
SL valves closes
—>S2 heart sound aka DUBB
SA Node name and function
Sinoatrial node
Pacemaker of the heart
Normal Sinus Rhythm
How does autorythmicity relate to the heart?
Autorythmicity is an organs ability to generate its own rhythm without outside stimuli. The heart beats at roughly 100/min.
SA Node Depolarization Rate
100x/min due to leakiest Na channels
How long do contractions take and long long is the refractory period of the heart.
Contractions last 250 mS
Refractory period lasts 250 mS
SA Node location
Base of Superior Vena Cava
What does the SA Node Stimulate
The Atria - Contraction
The AV node (Atrioventricular node)
What does each number represent?
- Resting membrane potential (-60mV)
- Na+ influx causes depolirazation
- Ca2+ channels open as threshold is reached (-40mV)
- Depolorization of the pacemaker potential
- K+ Efflux causes repolarization
AV Node Depolarization Rate
50x/min
AV Node location
At top of Interventricular septum
What is the name when AV Node becomes pacemaker
Junctional Rhythm
Junctional Rhythm is?
an abnormal heart rhythm that originates from the AV node or His bundle
What happens if SA Node fails
The AV Node will act as the new pacemaker, but an artificial pacemaker will be needed to speed up the AV Node
AV bundles Depolarization rate
30x/min
Purkinje Fibers Depolarization Rate
30x/min
Intrinsic Conduction System pathway regarding the Nodes
SA Node > AV Node > AV Bundles > R/L Bundle Branches > Purkinje Fibers
What is the range of normal Sinus Rhythm is?
between 60 and 100 beats per minute (BPM) in adults
Time from SA Node to Purkinje Fibers?
0.22 Seconds
What happens if we exceed the SA Node > Purkinje fibers time of 0.22 sec cycle
This results in a heart block
Primary heart block
1st degree block
What does each number represent?
- Resting membrane potential
- Voltage regulated Na+ channels open, influx causes depolarization (there is no threshold)
- Extracellular Ca2+ channels open
- Brief K+ Efflux causes dip In mV as attempted repolarization occurs
- Plateau; Sarcoplasmic Reticulum Ca2+ channels (Intercellular) open, maintaining depolarization.
- Efflux of K+ causes repolarization
Cardiac Output (CO) =
SV x HR
Stroke Volume (SV) =
70ml/beat
Heart Rate (HR) =
75beat/min
SV x HR =
70ml/beat x 75beat/min
70ml/beat x 75beat/min
5250 ml/min
What two systems have an influence on regulating SV & HR
ANS -
-Limbic System,
-Cerebral Cortex,
-Chemoreceptors - pH (CO2)
-Baroreceptors - Pressure
Endocrine
What does this graph and the numbers on it represent?
ECG/EKG
1. P-Wave: Atrial depolarization
2-4. QRS: Ventricular depolarization
5. T-Wave: Ventricular repolarization
6. ST Segment
7. PQ/PR interval
8. QRS complex
What occurs during mid-late diastole, where does it occur, and how does it present on an ECG/EKG?
Left Ventricle, presents as P-Wave (P-Wave is Atriole depolarization (Systole))
Ventricles pressure is low and AV Valve is open
Blood from atrium is passively moving into ventricle (70% of the blood in the heart)
Semilunar valve is closed (Ventricular pressure is less arterial pressure)
Atrial pressure increases, pushing last 30% of the blood into the ventricles resulting in End Diastolic Volume (EDV)
What happens during ventricle systole and how is that represented on the ECG/EKG?
Ventricular systole presents as the QRS complex
This is the Ventricular depolarization resulting in contraction
Ventricle pressure increases, becoming greater than Atrial pressure as the atria enters diastole
The closing of the AV valves result in the first sound we hear; the “lubb”
All 4 valves close in isovolumetric contraction
Ventricle pressure continues to build even greater than Arterial pressure
SL valves open, causing an ejection of blood we experience as the “feel” of a pulse, also called the Ventricular ejection phase
What occurs during Ventricular diastole and how does it present on an ekg/ecg?
This presents as the T-Wave
The ventricles relax, dropping ventricular pressure lower than Arterial pressure
SL valves close, resulting in the second sound we hear; the “dubb”
All 4 valves close in isovolumetric relaxation
We see the dictrotic notch, a surge in pressure w/I the aorta when the SL valves close that marks the end of systole/the start of diastole.
A small amount of blood remains in the ventricles (end systolic volume)
What Is stroke volume and what is the typical value for stroke volume?
Stroke volume (SV) is the End Diastolic Value (EDV) subtracted from the End Systolic Volume (ESV)
EDV is usually 120 ml and the ESV is usually 50 ml
120ml - 50ml = 70ml (SV)
What does the Sympathetic Division use
Neurotransmitter - Norepinephrine/Epinephrine
What is the center cavity of a blood vessel called?
Lumen