Chapter 15: The Cardiovascular System
List the vessels through which blood flows from the aorta to the myocardium and back to the right atrium
1) coronary arteries 2) myocardium 3)cardiac veins 4) coronary sinus 5) right atrium
Branches of aortic arch
Brachiocephalic, left common carotid, and left subclavian arteries
Arterioles
Branch into capillaries
Venules
Capillaries converge into these
Factors that influence arterial blood pressure
Cardiac output, blood volume, peripheral resistance, and blood viscosity
Precapillary sphincters open when
Cells are low on oxygen and nutrients
Precapillary sphincters close when
Cellular needs are met
Vasomotor fibers
Control diameter of vessels
Pericardium
Covering that encloses the heart. The pericardium consist of two layers the visceral pericardium and the parietal pericardium.
Parasympathetic
Decrease heart action Vagus nerves Acetylcholine
Venous blood flow
Depends on skeletal muscle contractions, breathing movements, and venoconstriction
P Wave
Depolarization of atrial fibers
QRS Wave
Depolarization of ventricle fibers and repolarization of atrial fibers
Blood-brain barrier
Endothelial cells of brain capillaries are tightly fused Substances move through by facilitated diffusion
Layers of the heart wall
Epicardium (outer), myocardium (middle), endocardium (inner).
Aortic valve
Guards the base of the aorta
Pulmonary valve
Guards the base of the pulmonary trunk
Mitral valve
Guards the left AV orifice
Tricuspid Valve
Guards the right AV orifice
Sympathetic
Increase heart action Accelerator nerves Norepinephrine
Cardiac control system
Located in the medulla oblongata
Diastolic pressure
Lowest pressure that remains in the arteries before the next ventricular contraction
Baroreceptor reflexes
Maintain balance between parasympathetic and sympathetic Located in cardiac control center
Systolic pressure
Maximum blood pressure achieved during ventricular contraction
Heart
Muscular pump that forces blood through arteries
Heart skeleton
Provides attachments for valves and muscle fibers and prevents orifices from excessively dilating during ventricular contractions
Left ventricle
Pumps blood into the aorta
Right ventricle
Pumps blood into the pulmonary trunk
Left atrium
Receives blood from the pulmonary veins
Right atrium
Receives blood from the venae cavae and coronary sinus
Electrocardiogram (ECG)
Records electrical changes in the myocardium during a cardiac cycle
Vasoconstriction
Reduces diameter Vasomotor fibers stimulate smooth muscle to contract
Precapillary sphincters
Regulate capillary blood flow
T wave
Repolarization of ventricle fibers
Veins
Return blood to the heart
Branches of the ascending aorta
Right and left coronary arteries
Blood flows through the vena cava and coronary sinus into the right atrium through the _____to the right ventricle through the pulmonary valve to the pulmonary trunk into the left and right _____ to the lungs and then leaves the lungs through the pulmonary vein and flows into the _____ through the mitral valve to the _____ and through the _____ to the aorta
Right atrioventricular orifice, pulmonary arteries, left atrium, left ventricle, aortic valve
Capillaries
Site of nutrient, electrolyte, gas, and waste exchange
Vasodilation
Smooth muscle fibers relax Diameter increases
The first heart sound is produced when
The AV valves close
Cardiac muscle fibers
The fibers connect in branching networks Joined by intercalated discs that include gap junctions
Visceral Pericardium
The layer of the pericardium that is closest to the heart. Folds over itself to form the parietal pericardium.
Central venous pressure
The pressure in the right atrium
The second heart sound is produced when
The pulmonary and aortic valves close
Pericardial cavity
The space between the visceral and parietal the layers of the pericardium
Arteries
Transport blood away from the heart
