A&P Term 3 Lab #3: Cardiovascular System I: Cardiac Physiology & Blood Vessel Histology Flashcards
The cardiovascular system consists of:
the heart and all the blood vessels
The heart consists of two receiving chambers, the ______.
atria (left and right atrium)
The heart consists of two pumping chambers, the ____
ventricles (left and right ventricles)
The left side of the heart pumps _______ blood and the right side pumps ________ blood
oxygenated, deoxygenated
The pulmonary circuit
all the blood vessels that take deoxygenated blood from the right ventricle of the heart to the lungs, and then return oxygenated blood to the left atrium
The systemic circuit
blood vessels that transport oxygenated blood throughout the body and returns deoxygenated blood back to the heart
All gas exchanges occur within ______
capillaries
Capillaries
microscopic blood vessels only one cell layer thick
What are capillaries walls made out of? why?
Their walls are made out of simple squamous epithelium, which permit the diffusion of gases such as O2 and CO2
O2 diffuses out of the blood and into body cells to be used in the process of _______ ________, whilst CO2 is a by-product of cellular respiration and gradually builds up within body cells before diffusing into the _______
cellular respiration, capillaries
The heart has two populations of cardiac myocytes. What are they? What is the percentage of each?
nonpacemaker cells = 99%
pacemaker cells = 1%
Nonpacemaker cells
regular/contractile myocytes
Pacemaker cells
specialized cells that have the unique property of spontaneously depolarizing and generating action potentials.
The action potentials they initiate trigger action potentials of the nonpacemaker cells.
The heart’s pacemaker cells are located in clusters throughout the heart, and together these clusters make up the ____ _____ ______
cardiac conduction system
Parts of the cardiac conduction system:
Sinoatrial (SA) node, Atrioventricular (AV) node, and the Purkinje system
Sinoatrial (SA) node (location + function)
located in the upper right atrium, where it acts as the main pacemaker of the heart. It depolarizes spontaneously around 60 times per minute (usually higher bc influence of the autonomic nervous system)
Atrioventricular (AV) node (location + function)
located in the lower right atrium, where it acts as backup pacemaker and is capable of pacing the heart at about 40 beats per minute
Conduction through the AV is ___, which is known as the __ _____ _____
slow, AV node delay
What is the function of the AV node delay?
allows the atria to depolarize and contract before the ventricles, which allows the ventricles to fill with blood.
Purkinje system
a group of pacemaker cells that transmitts impulses from the AV node to the ventricle
The myocytes of the purkinje system pace the heart slowly but conduct impulses more rapidly than the ________.
rest of the conduction system
3 components of the purkinje system
Atrioventricular (AV) bundle, Right and left bundle branches, Purkinje fibers
Atrioventricular (AV) bundle
small group of fibers in the lower interatrial septum and upper interventricular septum that transmits impulses from the AV node to the ventricles.
Right and left bundle branches
impulses are transmitted from the AV bundle down either side of the interventricular septum by the right and left bundle branches
Purkinje fibers
at the end of the interventricular septum, the right and left buncle branches fan out through the myocardium as the purkinje fibers. These fibers extend ⅓ of the way into the heart muscle before blending with the regular nonpacemaker cardiac myocytes.
Electrocardiogram abbreviations
(ECG or EKG)
what is an Electrocardiogram (ECG or EKG)?
a graph of the heart’s electrical activity as expressed in millivolts (mV) over time
Electrocardiograph
The instrument used to obtain an electrocardiogram (EKG)
A person is connected to the electrocardiograph with electrodes placed on…
the arms and legs (limb leads) and along the chest (chest leads)
An EKG is used to detect what?
if the electrical conduction pathway within the heart is normal and if any damage has been done to the heart