Ch. 20 Flashcards
The heart of a healthy adult beats how many times per min?
60-100
The PULMONARY CIRCULATION carries blood to?
what exhanged happens there?
Where is blood returned?
The RIGH side of the heart pumps Pulmonary circulation carries blood to the LUNGS, where Co2 diffuses from the blood to the lungs and 02 diffuses from lungs to blood. The oxygen rich blood is then returned to LEFT side of hear=rt
SYSTEMIC CIRCULATION is pumped on which side of heart?
and delivers what to where?
LEFT SIDE pumps systemic circulation which delivers oxygen and nutrients to all tissues of body.
CO2 and waste products are then carried back to right side of heart
Where is the heart located?
Between what intercostal spaces?
Mediastinum - midline portion of thoracic cavity
Base is 2nd intercostal space and Apex to the 5th intercostal space
2/3rds of hearts mass lies the left of midline of sternum
What are the 2 layers of pericardium?
What are the functions of outer layer of pericardium?
The inner layer is further divided into what 2 parts?
Visceral pericardium is also called?
The space between visceral and parietal cavities is called?
outer layer - fiberous pericardium - orevents overdistension & anchors to mediastinum. Attached to connective tissue covers of great vessels and on bottom to diaphram
Inner layer - Serous pericardium -
Parietal & Visceral
Epicardium - covers hearts surface
Pericardial cavity
What is function of pericardial fluid?
Reduce friction as heart moves
What 3 layers make up the heart wall?
Epicardium - Superficial layer
*Considered visceral pericardium when talking about pericardium / considered Epicardium when talking about hear
Myocardium - heart muscle cells
Endocardium -deep layer. Simple squamous epithelium over layer of connective tissue
What are the ridges on the auricles and right atrium called?
What separates the muscular ridges of right atrium from smooth portion of atrial wall?
The interior walls of ventricles contain larger muscular ridges called?
Pectinate muscles - whcih are ridges formed from myocardium
Crista terminalis
Trabeculae carneae - help with forceful ejection of blood from ventricles
What are the 4 chambers of the heart?
Where are atria located on heart?
Where are ventricles located on heart?
What is the auricle?
2 atria and 2 ventricles
Thin walled artia are superior and posterior (TOP)
Thick walled ventricles are inferior and anterior (BOTTOM)
Flap like extension of each atrium
What are the 2 large veins that carry blood from body to rgiht atrium?
Superior vena cava & Inferior vena cava
What carries blood from lungs to left atrium?
4 pulmonary viens
How does blood leave the ventricles?
Blood leaves the ventricles by 2 arteries: Pulmonary trunk & aorta
Pulmonary truck carries blood from right ventricle to lungs
Arota carries blood from left ventricle to body
What is coronary circulation?
consists of blood vessels that carry blood to and from the tissues of heart wall.
Left and right coronary arteries & great cardiac vein, small cardiac vein
Where are the following located…
Coronary sulcus
Anterior interventricular sulcus
Posterior interventricular sulcus
in a healthy heart, these grooves are covered by
Coronary sulcus - a large groove separating atria from ventricles
Anterior interventricular sulcus - Separeates right and left ventricles. This is on anterior side of heart
Posterior interventicular sulcus - Separates right and left ventricles on posterior side of heart
Adipose tissue
What are the 3 major branches of left coronary artery?
Anterior interventricular artery (desending) - supplies blood to most of the anterior part of heart
Left Marginal artery - supplies blood to lateral wall of left ventricle
Circumflex artery - supply blood to much of the posterior wall of heart
What are the 2 major branches of right coronary artery?
Right Marginal artery - supply blood to lateral wall of right ventricle
Posterior interventricular artery - supply blood to posterior and inferior part of heart
What are anastamoses?
Direct connections between arteries
What are the 2 major veins in coronary circulation?
Where do the 2 veins converge and empty?
Great cardiac vein - drains blood from left side of heart
Small cardiac vein - drains right margin of heart
Converge and empty into the coronary sinus, which in turn empties into right atrium
The right atrium has what 3 major openings?
Opening from superior vena cava, opening from inferior vena cava and opening from coronary sinus.
The superior and inferior vena cava recive blood from the body and coronary sinus recieves blood from the heart itself
The left atrium has which 4 unifrom openings?
4 pulmonary veins that receive blood from the lungs
The right and left atrium are separated from each other by a wall of tissue called?
The slight oval depression on right side of wall of tissue is called?_____Which is the former location of ______?
interatrial septum
fossa ovalis
foramen ovale - an opening in right and left atria in fetal heart to allow for passing of blood bypassing coronary circulation.
The atria open to the ventricles through what?
Blood flows from the right ventricle to …
Blood flows from left ventricle to ….
2 ventricles are separated by
atrioventrocular canals
Blood flows from right ventricle to pulmonary trunk
Blood flows from left ventricle to aorta
2 ventricles are separated by intraventricular septum
Each atrioventricular canal has a ______ that is a flap and it prevents ________
The flap between right atria and right ventricle is called?
The flap between the left atria and left ventricle is called?
atrioventricular valve which prevents blood from flowing back into atria’s, it ensures a one way flow.
Tricuspid valve - consist of 3 cusps
Bicuspid valve - 2 cusps
Papillary muscles
How do they work?
muscles that attach to cusps of the atrioventricular valves by thin strong connective tissue strings called chordae tendineae (heart strings)
These muscles contract when ventricles contract and prevent valves from opening into atria
What are the 2 semilunar valves?
What is their purpose?
Aortic semilunar valve
Pulmonary semilunar valve
Purpose is to prevent blood flow back into ventricles
The heart skeleton consist of
fibrous connective tissue between artia and ventricles. Forms a fibrous ridge around the atrioventricular and semilunar valves which provides solid support
fibrous connective tissue plate also serves as a electrical insulation and provides attachment of cardiac muscle
Charateristics of Cardiac muscles
Shaoe of cell…
of nuclei..
Striation?
How they contract?
How they get ATP
Organized? and bound by?
elongated branching cells
one or occasionally two centrally located nuceli
Contain actin and myosin to form sarcomeres - gives striated apparence
smooth sarcoplasmic reticulum which stores Ca2
T tubules near Z disc
rich in mitochondria
organized in spiral bundles or sheets
bound by intercalated disc’s
What are the nodes called?
and what is it celled where they meet?
Sinoatrial node (SA) Atrioventricular node (AV)
Atrioventricular bundle
What is the path of the atrioventricular bundle?
Passed through small opening in fibrous skeleton to reach interventricular septum where it divides to form R and L bundle branches.
These extend beneath the endocardium on each side of interventricular septum they descend to the apex then are carried by Purkinje fibers to ventricular walls and papillary muscles
Where do cardiac action potentials originate?
Sinoatria node (the pacemaker) SA NODE
Purkinje fibers
What are the phases of action potential in cardiac muscle?
- Depolarization phase - membrane potential quickly becomes more postive. Na2+ channels open, K+ channels close, Ca2+ begin to open
- Early repolarization phase - rapid & partial
* Na+ begin to close, some K+ open, Ca2+ open* - Plateau phase - prolonged period of slow repolarization
* Ca2+ close, many K+ open* - Final repolarization phase - membrane potential returns to resting level
* Cardiac muscl contracts and relaxes almost completely during refractory period*
What is CALCIUM INDUCED CALCIUM RELEASE (CICR)?
When an action potential occurs, Ca2 enters the cell and binds to receptors resulting in the opening of Ca2+ channels on the membrane of the sarcoplasmic reticulum, Ca2 then moves out of sarcoplasmic reticulum and activates interactions between action and myosin producing a contraction
Autorthythmic
What is ectopic focus?
What causes it?
Ectopic focus - any part of the heart other than SA node that generates a heartbeat
Causes are:
*SA node doesnt function properly
*Blockage of conducting pathways between SA node and other parts of heart
*When rate of AP outside of SA becomes enhanced - when cells are injured (inflammation or lack of blood supply, or certain drugs)
What is the process of cardiac muscle contraction, from SA node to heart contraction?
SA node spontaneously produces an action potential.
SA NODE and neighboring cardiac cells are joined by gap junctions
AP goes into contractile cell and down T tubule - opening a Ca2 channel allowing EXTRACELLULAR Ca2 to rush inside the cell.
Ca2+ then binds to SR ca2 channels which let more calcium out (Calcium induced calcium channels)
Ca2 flows out from SR and binds to tropomyosin. Allowing myosin to bind to actin and contract
ECG
Electrocardiogram
record of electrical activity of the heart
can reveal abnormal conduction pathways, hypertrophy, atrophy and approx location of cardiac muscle damage
What do the following of ECG tell
P wave?
QRS complex?
T Wave?
P wave is result of AP that cause depolarization of atrial myocardium, signals the onset of atrial contraction
QRS are 3 separate waves and signal ventricular depolarization and contraction
T wave signals ventricular repolarization and relaxation
What is PQ interval and how long is it?
What is QT interval and how long is it?
PQ interval represents time from begining of P wave (onset of atrial contraction to begining of their relaxation) to begining of QRS complex and last about 16 sec
QT interval is beginging of QRS wave (onset of ventricular contraction) to end of T wave (ventricular relaxation). Last about 36 sec
PQ - atrium contraction-relax 16 sec
QT - ventricular contraction-relax - 36 sec
What is ischemia?
Ischemia is obstruction of blood supply to the walls of the heart
How does pneumonia cause heart problems?
Bacteria cause the blood vessles to deposit the bacteria into the cardiac muscle where they release a toxin called pneumolysin which kills cardiac muscle cells.
This causes microlesions and scar tissue which damages the functioning of the heart.
Normal antibiotic for bacteria cannot be used here because it causes the bacteria cell walls to burst which in this case would cause more realease of pneumolysin causing more damage
Cardiac cycle is defined as
repetitive pumping process that begins with onset of cardiac muscle contraction and ends with beginging of next contraction
What is the proces of the cardiac cycle in detail?
- ACTIVE VENTRICULAR FILLING - SA node generates AP -> atrial contraction, forces blood to ventricles
- PERIOD OF ISOVOLUMETRIC CONTRACTION- AP passed to AV node -> bundle ->purkjne fibers producing ventricular contraction causing blood to flow toward atria and close AV valves.
- PERIOD OF EJECTION - Pressure in ventricles increases until overcomes pressure in aorta and pulmonary trunk - valves open and blood is pushed to arteries
- PERIOD OF ISOVOLUMETRIC RELAXATION - Ventricles relax, blood begins to flow down aorta and trunk causing valves to close.
What does Systole mean?
Dystole?
Atrial systole?
Ventricular systole?
What is systole and dystole are alone?
Systole - contract
Dystole - to dilate
Atrial systole - contraction of atrial myocardium
Ventricular systole - contraction of ventricular myocardium
End diastolic volume (EDV)
End systolic volume (ESV)
EDV -volume of blood in ventricles when they were relaxed
What is intrinsic regulation?
Extrinsic regulation?
Intrinsic regulation - results from hearts normal functional characteristics - functions whether heart is in body or not
The heart is innervated by parasympathetic and sympathetic divisions, which one affects the heart more and what do these systems do to keep the heart in balance?
What are the parasympathtic fibers that innervate heart?
How does sympathetic division innervate heart?
Sympthetic division can increase cardiac output by 50-100% over resting values, where para can cause only a 10-20% decrease
These division help keep blood pressure, blood O2, blood CO2, and blood ph within their normal range
Parasympathetic - Vagus nerve - has an inhibatory effect - decreasing heart rate
Sympathetic - innervates heart by nerves in thoracic region of spinal cord innervate heart as cardiac nerves - increases heart rate and force of contraction
Secretion of epinephrine and norepinephrine is controlled by _________ division of the ________medulla. It occurs in response to …….
Secretion of epinephrine and norepinephrine is controlled by SYMPATHETIC division of the ADRENAL medulla. It occurs in response to …….
physical activity, emotional excitment, stressful situations
Baroreceptor reflexes
Detect changes in blood pressure
Dectect this by stretch receptors in the walls of blood vessels and communicate with control center in medulla oblongata
Chemoreceptor reflexes
Chemoreceptor reflexes help regulate hearts activity
Sensitive to changes in CO2 levels, blood ph
What happens when there is excess extracellular K+?
Causes heart rate and stroke volume to decrease.
Causes a heartblock- loss of AP conduction through heart
What is the process for autorythmic cells to send an AP?
Autorythmic cells have no “resting potential” however, their starting point or PACEMAKE potential is APPROX (-60mv to -41mv)
They spontaneously depolarize by FUNNY channels which leak Na2+. once enough Na2+ has leaked in they reach threshold of -40mv
A influx of Ca2 comes in and they become more positive generating an AP
They repolarize by closing Ca2+ channels and opening K+ channels
What is the process for contractile cells to send an AP?
The resting membrane potential is -90 mv
AP enters contractile cells via gap junctions via intercalated discs, causing Na2+ to open - Na2+ rushes out causing cell to repolarize to 20MV
The K+ channels open, allowing K+ to leave - repolarizing the cell ALSO we have Ca2+ open causing Ca2+ to rush in DELAYING the repolarization process resulting in PLATEAU (refractory period - contract during this time)
Slow K+ channels open which leads to repolarization
Extrinsic innvervation - modified by ANS
What is the cardioacceleratory center?
What is the cardioinhibitory center?
Cardioacceleratory center sends signals through sympathetic truck to increase rate and force.
*Stimulates SA, AV nodes, heart muscle and coronary arteries
Cardioinhibiatory center sends signals via parasympathetic to decrease rate
*Inhibits SA & AV nodes via vagus nerve
What are defects in extrinsic innervation of the heart?
If SA node is defective, what can happen?
- May cause heart block - Few or no impulses reach ventricles
Treatment: Artificial pacemaker
- Ectopic focus - slower beats/min
Auscultation?
First “lubb” is made by?
Second “Dupp” is made by?
Ausultation - listening to sounds made my body
First lubb is made by closure of AV valves, turbulence in bloodstream and movements of heart wall
Second dupp is made by closure of semilunar valves, turbulence of bloodstream and movement of the heart wall
Where on chest can I hear the following valves…
Aortic?
Pulmonary trunk?
Mitral - bicuspid?
Tricuspid?
Aortic valves can be heard in 2nd intercostal space at right sternal margin
Pulmonary trunk valves heard in 2nd intercostal space at left sternal margin
Bicuspid valves can be heard over heart apex in 5th intercostal space, in line with middle clavicle
Tricuspid valve can be heard in right sternal margin of 5th intercostal space
What is a heart murmur?
What is incompetent valve?
What is Stenoic valve?
Heart murmur - abnormal heart sounds when blood hits obstructions
Usually indicates valve problems
Incompetent valve - fails to close completely, allowing backflow of blood / swishing sound
Stenoic valve - fails to open completely, restricting blood flow through valve / high pitched or clicking sounds
What is STROKE VOLUME and how is it calculated?
What is ESV?
What is EDV?
STROKE VOLUME is amount of blood pushed out of ventricles during a contraction
SV = EDV - ESV
ESV is END SYSTOLIC VOLUME - amount of blood in ventricles before they contract
EDV - END DYSTOLIC VOLUME - amount of blood in ventricles after they contract
Parasymptathic - What does ACH do to pacemaker cells?
Sympathetic - What effect does norepinephrine do to pacemaker cells?
ACH - Hyperpolarized by opening K+ channels = slower HR (little or no effect on contractility)
Norepinephrine - causes pacemaker to fire more rapidly - increases contractility
What effects do the following have on heart rate?
HORMONES
Epinephrine ?
Thyroxine?
IONS -
Epinephrine - increases HR and contractility
Thyroxine - increases HR and enchances effects of epinephrine and norephinrine
IONS - balance must be maintained, imbalances are very dangerous
What age has fastest HR?
Gender?
Increase with excersice?
Increase with temp?
Fetus has fastest HR
Female has faster HR
Increase with excersice
Increase with temp
What is tachycardia?
What causes it?
What is bradycardia?
What causes it?
Tachycardia - Adult HR greater than 100 bpm
Causes: stress, anxiety, drugs, heart disease, fever / loss of blood or damage to myocardium
Bradycardia - Adult HR less than 60 bpm
Causes: in sleep, low body temp, endurance trained athletes
How do the following effect the heart
Hypocalcemia (low Ca2+)
Hypercalcemia (high Ca2+)
Hyperkalemia (high potassium)
Hypokalemia (low potassium)
Hypocalcemia (low Ca2+) - depresses heart
Hypercalcemia (high Ca2+) - increases HR and contractility
Hyperkalemia (high potassium) - alters electrical activity, lead to heart block or cardiac arrest
Hypokalemia (low potassium) - results in feeble heart beat, arrhythmias
What is a normal SV?
What are 3 main factors that affect SV?
120ML (EDV) - 50 ML (ESV) - 70 ml/beat
Preload, contractility, after load
What is preload?
Preload - degree of stretch of cardiac muscle cells before they contact
What is the formula for BP and what are the units we use?
Force
Surface area
units are mmhg (units of mercury pillar)
