Exam 1 Heart Review Flashcards
Fibrous Skeleton of the Heart
- Separates atria & ventricles
- Anchors heart valves
- Provides electrical insulation between atria & ventricles
- Provides framework for attachment of
myocardium
Heart Wall
-
Pericardium outermost later (thin) is the membrane that surrounds and protects
the heart. It ANCHORS heart to diaphragm with fibers. Fibrous layer of Parietal Pericardium - Outer and is tough tissue. Pericardial cavity contains about 30 ml of pericardial fluid Visceral Pericardium (aka epicardium) directly attached to myocardium deep to pericardial cavity -
Myocardium middle layer Myocardium is responsible for pumping action and is
made of two (2) layers of muscle. (Superficial and Deep) 95% of heart wall is made
up of this -
Endocardium innermost layer (thin) continuous with the endothelium of blood
vessels
External Surface of the Heart
Has Coronary, Ant, and Post Sulci. Has fat and blood vessels. Coronary sulcus is a large groove / deep on the outside of heart has fat separates atria from ventricles. Ant and Post
interventricular sulci external boundary separates RT and LT ventricles shallow
Right Atrium
From right boarder of heart To lungs “Fossa
ovalis” After birth no “Foramen ovale” it
is before birth (normally). Deoxygenated 3
sources of blood. 1- Superior Vena Cava
2- Inferior Vena Cava 3- Coronary sinus.
Sends blood to right atrium through
tricuspid valve (rt atrioventricular valve).
Blood flow through the Heart
1- Superior or Inferior vena cava
2- RT Atrium
3- Tricuspid Valve (RT AV valve)
4- RT Ventricle
5- Pulmonary Semilunar Valve
6- Pulmonary Trunk and Arteries
7- Lungs
8- Pulmonary Veins
9- LT Atrium
10. Bicuspid Valve (Mitral) (LT AV Valve)
11. LT Ventricle
12. Aortic Semilunar Valve
13. Ascending Aorta
14. Arch of Aorta
15 Systemic Circulation Start over to 1.
Left Ventricle
Pumps Blood out to body therefore has
Thicker walls. Has Trabeculae carne,
receives blood from LT Atrium, Bicuspid
valve (mitral) has chordae tendineae
(fibers) that anchor valve to papillary
muscles. Left ventricle has a CIRCULAR
LUMEN pumps blood into aortic
semilunar valve against great pressure.
Cardiac Valves
Fibrous skeleton around valves. Prevent
backflow of blood ensure a one-way flow. -> NOT ALL VALVES HAVE STRINGS OR
CHORDS (chordae tendineae) Semilunar valves (No chordae tendineae Nochords) Aortic Semilunar andPulmonary Semilunar
Bicuspid valves (left side) and Tricuspid
valves (right side) do have chords,
Does blood flow back into the vena
cavae and coronary sinus during
atrial contraction?
The compression of the right atrium
during systole prevents this.
When the ventricles contract
the —– valve close and the
—– valve are pushed open.
Tricuspid Right AV and Pulmonary Semilunar
or
Bicuspid (Mitral) Left AV and Aortic Semilunar
Circulation of Blood
The pulmonary circulation transports
blood from the heart to the lungs and back
to the heart. The first blood vessel in the systemic circuit is the aorta.
The systemic circulation circuit receives blood from the left ventricle. The right side of the heart is the pump for the pulmonary circuit.
Coronary Arteries
Right Coronary Artery
Anterior interventricular branch
Circumflex artery
Left Coronary Artery
Posterior interventricular branch
Marginal branch
Cardiac Muscle Tissue
- bifurcated (branched) cells
- intercalated discs
- numerous large mitochondria
- striations
Autorhythmic Cells of the
Heart
depolarize to threshold “spontaneously”
Due to slow Na+ Channel inflow
Primary Pacemaker of the
Heart
Sino Atrial Node “SA Node”
Sets establishes basic rhythm of
Cardiac action potentials for heart beats
per minute
Cardiac Conduction System
order of events
1- SA NODE
2- AV NODE
3- AV Bundle
4- Bundle Branches
5- Purkinje Fibers
Cardiac Conduction System
- The AV node can take over the pacemaking task if the SA node is damaged.
- The pacemaking ability of the AV bundle alone is not sufficient to maintain homeostasis.
- Ectopic pacemakers may be stimulated by caffeine or nicotine
- Ach release by the parasympathetic division
of the ANS decreases SA node
depolarization
Plateau phase of a cardiac
contractile action
- opening of voltage-gated slow Ca2+ channels
- release of Ca2+ from the sarcoplasmic reticulum.
- entry of Ca2+ from the interstitial fluid
- decreased permeability to K+ due to closing
of some K+ channels
Refractory Period of cardiac
muscle fibers
- Is a time interval during which another contraction is prevented.
- Is much longer than their contraction
period. -
Prevents tetany and allows the heart to
act as a pump.
Cardiac Muscle
- Most of the ATP production is aerobic
- Most of the ATP used while at rest comes
from oxidation of fatty acids - ATP is produced from creatine phosphate
- O2 is passively transported across the
sarcolemma. - Lactic acid production increases during
exercise.
an electrocardiogram
(ECG or EKG) detects
- cardiomegaly (enlargement of the heart)
- ischemic coronary blood vessels
- disturbances of the conduction pathway
of the heart. - damage to certain regions of the heart
QRS Complex
- ventricular depolarization
- atrial repolarization
prolonged P-Q interval
A patient may have coronary artery
disease or rheumatic fever.
Correlations between cardiac
contractions and ECG waves.
- Atrial systole begins immediately after P wave
- All chambers are relaxing during the period. between the T wave and the next P wave.
- Ventricular systole begins at the end of QRS complex.
- Atrial diastole occurs during the appearance of the QRS complex.
- Ventricular diastole follows the appearance of the T wave.
A single cardiac cycle
- Lasts .8 sec (8/10 th) when the heart rate is 75 beats/minute.
- Forces blood from areas of lower pressure to areas of higher pressure.
- Occurs dependently of electrical activity
in the heart. - Includes all of the events associated with
one heartbeat.
Events occurs during Ventricular Systole
- isovolumetric contraction
- ventricular pressure rises
- opening of the SL valves
Relaxation Period of the Cardiac Cycle
- It is a time when the atria are relaxed
- It is a time that becomes shorter as the
heart rate increases. - It is a time when the AV valves are open.
- It is the time when the ventricles receive
most of the blood from the atria. - It is a time when the SL valves are closed.
End of Atrial Systole
amount of blood contained in a
ventricle is the end-diastolic
volume EDV
Isovolumetric Contraction
During the cardiac cycle the interval
during which cardiac fibers are
contracting but not shortening. The
intraventricular pressure increases,
but the ventricular volume remains
the same.
Heart Sounds
Heart sounds- Lubb-dupp (lub-dup) a
representation of the normal heart sounds as
heard through the stethoscope. The first
coincides with closure of the mitral and
tricuspid valves; the second with closure of
the aortic and pulmonary valves. Closing of
valves make heart sounds (heart beat).
Cardiac Output I
- HR x SV in each ventricle each minute “Product of Stroke Volume and Heart Rate from each Ventricle”
- Is the volume of blood ejected from the right ventricle into the pulmonary trunk each minute.
- Is the volume of blood ejected from the left
ventricle into aorta the each minute.
Cardiac Output II
CO = EDV 130 ML – ESV 60 ML = SV 70 ML
X HR in 70 BPM) = 4900 ML = 4.9 L EACH
ventricle
EDV= End Diastolic Volume (Ventricles Full)
ESV= End Systolic Volume (Ventricles
Emptying but not completely empty)
SV= amount leaving heart EDV-ESV=SV
Cardiac Reserve
Amount of excess between Normal
C.O. and Maximum C.O. 20L Max – 5L Normal = 15L Reserve
Stroke Volume Regulation
- adjusting the afterload, the pressure that must be overcome to open an SL valve
- adjusting the contractility, or strength of contraction of the heart at a given
preload. - adjusting the preload, or degree of
stretch on the heart before it contracts
Frank-Starling law of the Heart
The greater the preload on cardiac
muscle fibers, the greater the force
of contraction will be.
Edema
Left Heart Failure = Left ventricle
failure or blockage, Results in Pulmonary Edema=Lung Fluid
Right Heart Failure = Right ventricle
failure or blockage, Results in Systemic
or Peripheral Edema
Regulation of Heart Rate I
- Nervous system control is originates in the
cardiovascular center of the medulla oblongata. - Parasympathetic impulses travel to the heart
primarily along the vagus (X) nerves. - The limbic system can influence the
cardiovascular center of the medulla oblongata. - Proprio-, chemo-, and baroreceptors detect
changes and influence the cardiovascular center. - Increased stimulation by the cardiac accelerator nerve increases heart rate.
Regulation of Heart Rate II
- Ach - Decreases HR
- Epinephrine - Increases HR
- Norepinephrine - Increases HR
- Hyponatremia - Increases HR
- T3/T4 - Increases HR
Regulation of Heart Rate III
Regular exercise tends to reduce resting
heart rate in both males and females.
Pectinate muscles
Internal walls of the
right and left atria and auricles.
Myocardial Infarction
- Results from an interrupted blood
supply to part of the heart. - Causes death of part of the heart.
- Is usually treated with anti-coagulation
therapy.
Isovolumetric Contraction
During the cardiac cycle the interval
during which cardiac fibers are
contracting but not shortening. The
intraventricular pressure increases,
but the ventricular volume remains
the same.
Right Atrium and
Right Ventricle
Are located anteriorly in a heart in
normal position.
Plateau phase of a cardiac
contractile action
- opening of voltage-gated slow Ca2+ channels
- release of Ca2+ from the sarcoplasmic
reticulum. - entry of Ca2+ from the interstitial fluid
- decreased permeability to K+ due to closing
of some K+ channels
