Chapter 20 Cardiovascular Flashcards
Blood
maintains homeostasis by moving, heart moves the blood
Heart beats 100,000 times per day, enough to fill 40- 55 drums
Pulmonary Circuit
transports blood to/from lungs back to heart
Systemic Circuit
transports blood to and from the rest of the body
Coronary Circuit
transport blood to provide nutrients to cardiac cells
arteries(efferent vessels)
carries blood away from heart, normally carries 02
veins (afferent vessels)
carries blood back to heart, normally C02
small thin membrane vessel, also called exchange vessels because these exchange gases with the cells
capillaries
Location of the Heart
located near anterior chest wall, slightly to left of mid-line, apex inferior part of heart, base superior part of heart
The Heart consists of
- Outer covering
- Inner walls
- Chambers
- Valves
Outer covering of heart
Pericardium
The Pericardium is made up of 2 membranes
Fibrous membrane
Serous membrane
forms the superficial layer, made up of dense irregular tissue
Fibrous membrane
thinner more delicate layer, made up of two sublayers:
Serous Membrane
Parietal layer- layer directly under fibrous layer, lines the inner surface of pericardial sac
Serous viscersal- innermost layer, also called epicardium cover the out surface of the heart
Serous membrane sublayers
the area between Parietal layer and serous visceral layer
Pericardial cavity
fills the area between (pericardial cavity) these two linings to reduce friction as the heart beats
Pericardial fluid
Heart Wall Has 3 Layers
Epicardium
Myocardium
Endocardium
Epicardium
outer layer heart, also called Serous visceral layer
Myocardium
muscular wall of heart that forms atria and ventricles, middle layer, made up of cardiac muscle (involantary striated)
Endocardium
inner layer made up of simple squamous, covers tendons and valves
connected by “intercalated disks” (double membrane that connects two adjacent cells which allows the contraction command to be passed from cell to cell through gap junctions. Smaller then skeletal muscle cells, has single centrally located nucleus, branching connections between cardiac cells.
Cardiac muscle cells
receives blood from systemic circuit and passes to right ventricle
Right Atrium
pumps blood into pulmonary circuit
Right Ventricle
receives blood from pulmonary circuit and passes to left ventricle
Left atrium
transports blood to systemic circuit
Left Ventricle
Right Ventricles and Left Ventricles
contract they eject equal volumes of blood
What do the anterior interventricular sulcus and posterior interventricular sulcus separate?
The left and right vetricles
What is an expandable extension of an atrium?
Auricle
Deep groove between atria and ventricles usually filled with fat?
Coronary Sulcus
Receives blood from two great veins, the superior vena cava, and the inferior vena cava.
Right Atrium
Blood coming from head, neck, upper limbs and chest.
Superior vena cava
Blood coming from lower trunk and lower limbs.
Inferior vena cava
Superior vena cava and Inferior vena cava empty into what?
Coronary Sinus
An area the blood combines into prior to enter the right atrium.
Coronary Sinus
Before fetus is fully developed inside the womb, the right atria and left atria are connected allowing blood to flow through this because the lungs are not fully developed.
Foramen ovale
Muscles that are in both the wall and auricles of the Right atrium.
Pectinate muscles
Closed but as blood volume increases it opens up the valve allowing blood to pass into the right ventricle. The atria will contract forcing last of blood into right ventricle.
Tricuspid Valve
Blood flows from RA to RV through opening called
right atrioventricular valve
The right AV valve closes after blood fills the ventricle, then the RV contracts causing the blood to be ejected from RV through the
pulmonary semilunar valve
Both ventricles have ______ to which _________ anchor the cusps of the atrioventricular valves
trabeculae carneae, papillary muscles
Blood enters the_____ until its filled, the valve between the LA and LV is closed
Left atrium
The valve between the LA/LV is the _________
left atrioventricular valve ( left AV, mitral valve, biscuspid)
Pectinate muscles are ONLY in the __________ NOT in the _______ of this chamber
auricle, walls
The _____ wall is thicker due to pressure required to push the blood through the systemic circuit.
left ventricle
Blood leaves the left ventricle by passing through the _________ into the __________
aortic semilunar valve, ascending aorta
Blood passes from Ascending aorta through the _______ into the ______.
aortic arch, descending aorta
Prevents backflow of blood from ventricles in to atria
Atrioventricular valves
The Biscuspid (mitral valve) is also known as the ______ valve
left av
The Triscuspid valve is also known as the _______ valve
right av
Prevents backflow of blood from the pulmonary trunk and aorta into ventricles
Semilunar Valves
Heart cells receive blood supply from the _______
coronary circuit
The right and left coronary arteries begin at the ________
ascending aorta
When the L ventricle relaxes, blood stops flowing into the aorta and pressure declines, causing the aorta to recoil causing ___________
elastic rebound
Causes blood to pushed into coronary arteries
elastic rebound
Provides blood to the R atrium, both ventricles, and both AV and SA nodes.
right coronary artery
Provides blood L atrium, L ventricle, and interventicular septum
left coronary artery
Cardiac cells involved in heart beat
- specialized cells of conducting system
2. contractible and contractile cells
This muscle contracts on its own
cardiac muscle
located in right atrium
sinoatrial (SA) node primary pacemaker
located in the junction between right atrium/right ventricle
antrioventricular (AV) node
conducting cells found in the atria, they are found in the _______ , pathway between SA and AV node
internodal pathway
conducting cells found in ventricles, they include _________ and ___________
AV bundle, Purkinje Fibers
The Conducting System contains
sinoatrial (SA) node
atrioventricular (AV) node
conducting cells
located in posterior wall of right atrium near entrance of superior vena cava and smaller node
SA node- sinoatrial node
contains pacemaker that starts contractions and stimulates the AV nodes
SA node- sinoatrial node
innervated by the Vagus nerve and Sympathetic nerve
SA node- sinoatrial node
The stimualtion of the Vagus nerve causes a decrease in SA node rate and decreasing heart rate by _______ being released from vagus nerve endings, which bind to ___________ on the pacemaker cell membrane
ACH, muscarinic receptors
The stimulation of the sympathetic fibers causes an increased heart rate due to the ______ released from the nerve endings which bind to ___________ on pacemaker cells
NE, adrenergic receptors
SA node command to contract id carried to AV by one of 2 different methods
1) via internodal pathway
2) via each contracting cell’s gap junction to contract cell
- larger node at bottom of Atrium
- takes 100 m/sec for impulse to pass through AV node and enter the AV bundle
- only electrical connection between atria and ventricles is the AV bundle (bundle of his)
- AV bundle impulse travels through interventricular septum to bottom of ventricles, where they stimuate Purkinje fibers, which relays impulse to throughout both ventricles
AV node
Bundle of His
AV bundle
faster the then normal heart beat
tachycardia
slower then normal heart beat
bradycardia
Conducting System
- SA node is activated
- Stimuli spreads from SA across both atria and reaches the AV node
- Stimuli is delayed, then both atria contract
- Stimuli travels along interventricular septum within AV bundle, will branch to become the Purkinje fiber
- Purkinje fibers distribute stimuli to the myocardium, causing ventricles to contract
These cells receive the stimuli; resting potential is about -90 mV for the ventricular cardiac cells, and about -80 mV for the atrial cardiac cells; skeletal muscle is around -85 mV. Ventricular cardiac cells reach threshold of -75 mV
Contractile cell
the channels open and Na+ ions enter; threshold is -75 mV
Rapid depolarization
when transmembrane potential reaches 30 m, Na channels close and transmembrane potential becomes a little bit more negative as Na is pumped out ; but when Ca+2 channels open and Ca+2 enters the cell and binds to troponin same as skeletal muscle; potential remains at 0
The Plateau
slow Ca+2 channels close and slow K+ channels open so K+ rushes out to reduce positive charge in cell.
Repolarization
the time when a cell will not respond to a second stimuli, last 200 msec
Absolute refractory period
short time after the absolute refractory period; cell will not respond to normal stimuli but will respond to greater stimuli
Relative refractory period
has a longer relative period but shorter absolute refractory period
skeletal muscle
has shorter relative period but longer absolute refractory period
cardiac muscle
the period between start of one heartbeat and the beginning of another heartbeat, is divided into 2 phases
Cardiac cycle
when the section/chamber of the heart contracts; blood leaves the chamber during contraction
Systole
when the section chamber of heart contracts; blood enters the chamber for rest
Diastole
Phases of Cardiac Cycle
- atrial diastole
- atrial systole
- ventricular systole
- ventricular diastole
atria fills with blood; AV valve open; 70% of blood passively enters ventricle
atrial diastole
atria contracts, pushing remaining blood 30% into ventricles
atrial systole
AV valves close; semilunar valves open as blood is ejected into arteries; pressure in aorta reaches 120 mmHg
ventricular systole
semilunar valve close; AV valves open; blood passively enters ventricles from atria; aorta rebounds and pressure drops to 80 mm Hg; all chambers are relaxed
ventricular diastole
normally use artery in wrist or neck; depress artery against bone to feel the blood ______ through the vessels
Pulse
ECG or EKG
Electrocardiograph
listening to heart sounds with a stethoscope
auscultation
depolarization (contraction) of the atria
P wave
signal ventricles depolarization (contraction); this is large due to ventricle muscle being more massive then atrium
QRS wave
signals ventricular depolarization (relaxation)
T wave
there are ___ heart sounds, but normally we can only hear two of them S1 and S2
4
sounds like “lubb”, caused by the AV valve (biscuspid/mitral valve and tricuspid) closing
S1
sounds like “dubb”; this is caused by the closing of semilunar valve in ventricles
S2
cannot be heard, flood flowing into ventricle
S3
cannot be heard, atrial contraction
S4
Cardiac Output
amount of blood pumped per minute
Formula for CO (cardiac output)
Cardiac Output = Heart Rate x Stroke Volume
CO = HR x SV
the amount of blood (about 130 mL) in each ventricle at the end of ventricle diastole
EDV End Diastolic Volume
the amount of blood ( about 50 mL) left in each ventricle at the end of ventricular diastole
ESV End Systolic Volume
Stroke Volume
EDV - ESV = SV
amount of blood about 70 to 80 mL pumped out of each ventricle during a single beat
Stroke Volume (130 mL - 50 mL = 80 mL)
Changes in EDV can be affected by
- filling time
2. venous return
Frank Starling Principle
“more in, more out”
Changes in ESV
- preload
- contractilty of ventricle
- after load
Factors affecting heart rate
- ANS
- hormones
- venous return
