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