Module 3 Flashcards
Components of the cardiovascular system
Heart atria, ventricles, blood vessels (arteries, capillaries, and veins) and AV valves
Major function of the CVS
The major function of the CVS is the transport of nutrients (including oxygen) and waste products of metabolism.
Systemic circulation
The left heart pumps blood to all organs of the body.
pulmonary circulation
The right heart pumps venous blood through the lungs, where carbon dioxide is exchanged for oxygen
how many chambers on each side of the heart
2 (atrium and ventricle)
Semilunar Valves
prevent back flow of blood from the aorta and pulmonary arteries into the left and right ventricles, respectively
Arterioles
bring blood to the capillaries and regulate the amount of blood supplied to the tissues
Venules
drain blood from the capillaries
Path of blood flow in the body
right atrium -> right AV valve (tricuspid)-> right ventricle->right semilunar valve (pulmonary)->pulmonary artery->lungs->pulmonary vein-> left atrium
characteristics of the heart muscle
striated, mononucleated (single nucleus per cell), and involuntary
syncytium
cells forming a functional unit : Heart muscle fibers are interconnected by intercalated discs to allow for rapid transmission of impulses from cell to cell.
Because of this, they form one functional unit
where does the heartbeat originate
spontaneously at the sino-atrial node (SA node)
SA node
sino-atrial node->a collection of specialized cardiac muscle fibers located at the junction of the cranial vena cava and the right atria
pacemaker of the heart
conduction system of the heart
Impulses from the SA node travel to the atria, and the atria contract -> Impulses reach the AV node -> Impulses are delayed at the AV node, allowing time for the ventricles to fill with blood -> Impulses travel through Purkinje fibers to the ventricles, which contract and eject blood into the aorta and pulmonary artery
systole
Contraction of heart muscle (usually refers to ejection of blood from ventricles into the pulmonary artery or aorta
Diastole
Relaxation of the heart muscle (usually refers to the filling of the ventricles with blood)
how can heart muscles generate a rythmic beat without nerve stimuli
Heart muscles are capable of depolarizing
Parasympathetic
this system is most active during rest. Its action on the heart is mediated through the paired vagus nerves (cranial nerve X, CN10). The parasympathetic effects on the heart can be summarized as follows:
Decreased rate of discharge at SA node
Decreased rate of conduction of impulses within the heart
Decreased rate and force of heart muscle contraction
sympathetic
system is most active during exercise and emergency situations, in order to supply more blood to the skeletal muscles and the brain. Sympathetic effects on the heart can be summarized as follows:
Increased rate of impulse conduction within the heart
Increased rate and force of heart muscle contraction
Cardiac output (CO). or cardiac minute volume
concept designed to express the amount of blood the heart pumps into the aorta, and thus systemic circulation, in a determined amount of time.
the equation for cardiac output
Cardiac output (CO) = heart rate * stroke volume
venous return
The amount of blood returned from the general circulation to the right atrium each minute should equal cardiac output in order for the cardiovascular system to maintain homeostasis.
Venous return = cardiac output (meaning: the heart pumps the blood that returns to it by the veins)
equation to estimate blood flow
Blood flow = (difference in pressure) / (resistance)
What determines resistance
arteriole diameter