Midterm 2 Flashcards
active hyperemia -
An increase in blood flow in response to increased metabolic activity of the tissue. The increase in blood flow helps meet the increased metabolic demand of the tissue.
arteries -
The first branch of blood vessels in the vascular tree on the arterial side of the systemic circulation. Thick-walled, muscular blood vessels that carry blood flow away from the heart to the entire body and branch into smaller.
arterioles -
A small diameter blood vessel that branches from an artery and leads to capillaries. Have muscular walls that are highly innervated by sympathetic motor neurons, and are thus the primary site of vascular resistance. Often referred to as the resistance vessels.
atria -
The smaller upper chambers of the heart. The right receives venous return from the systemic blood flow circuit and pumps blood into the right ventricle. The left receives blood from the pulmonary blood flow circuit and pumps blood into the left ventricle.
atrioventricular (AV) node -
A group of pacemaker cells located in the right atrium. Has a rate of self-depolarization of 40 to 60 bpm. Imposes a brief delay on the action potential leaving the SA node before the action potential enters the ventricles.
av-O2 difference
The difference in the amount of oxygen in the arterial blood and the venous blood. Every organ has an this difference. For the whole body reflects the amount of oxygen used by the body. The unit values for are mL of oxygen per dL of blood flow (mL/dL).
bicarbonate -
The majority of carbon dioxide is transported in the blood as this. Carbon dioxide reacts with water to form carbonic acid, which quickly dissociates into hydrogen and this. The reaction reverses at the lungs so carbon dioxide can be expired.
blood shunt -
The redistribution of blood flow based on metabolic demand so that there is a decrease blood flow to less metabolically active tissues (the visceral organs except the heart and liver) and an increase in blood flow to more metabolically active tissues (skeletal muscle). Results primarily from vascoconstriction and vasodilation of blood vessels due to neural stimulation and also local control of arterioles and capillary beds.
BOHR effect -
The shifting down and to the right of the oxygen association-dissociation curve due to an increase in temperature and partial pressure of carbon dioxide and a decrease in pH. The shift in the curve reflects the decreased affinity of oxygen for hemoglobin, allowing a greater amount oxygen to become unbound to hemoglobin and diffuse into the tissue.
Boyles law -
This law states that as the volume of a gas decreases, the pressure exerted by the gas increases proportionately.
capillaries -
The smallest blood vessel branching from arterioles. Do not have smooth muscle and therefore do not vasoconstrict and vasodilate as do other blood vessels. Perfusion of blood into a capillary beds is increased or decreased by relaxing or contracting the pre-capillary sphincter muscles. Although capillaries are the smallest blood vessels, collectively they have the largest total cross sectional area. Are often referred to as the exchange vessels.
capillary bed -
A network of capillaries through which blood flow is regulated by relaxing or contracting the pre-capillary sphincter muscles.
carbamino hemoglobin -
The term used to describe the binding of carbon dioxide to hemoglobin. About 20% of carbon dioxide is transported in the blood as ______.
cardiac output (Q)
The amount of blood pumped from the heart into the systemic circulation per minute. Is the product of heart rate and stroke volume (Q mL/min = HR bpm x SV mL/b). Is typically expressed in L/min rather than mL/min.
chordea tendinae -
Cords that attach to the ventricular side of the tricuspid and mitral valves that help to prevent back flow of blood into the atria when the ventricles contract.
chronotropic -
Referring to time. In the context of the heart, referring to heart rate. Something that has a positive _______ effect increases heart rate whereas something that has a negative _______ effect decreases heart rate.
compliance
The ability of a blood vessel to distend (enlarge) with an increasing amount of pressure coming from the inside of the vessel (blood pressure). Highly compliant vessels, for example, the veins will distend under high pressures. Vessels of the arterial side of the circulation are less compliant than veins.
conduction cells -
Specialized cardiac cells that form the conduction pathways in the heart. The conduction pathways conduct action potentials from one area of the heart to another, for example, from the SA node to the AV node.
contractility
The intrinsic ability of cardiac muscle cells to form actin-myosin crossbridges. An increase in contractility allows the myocardium to contract more forcefully regardless of the length of the muscle cells. Thus, it is independent of filling due to venous return (i.e., preload) and afterload. The _______ of the myocardium increases due to sympathetic stimulation.
diastole
The time period (seconds) during which the heart is resting. During _______, the chambers of the heart fill with blood and the heart receives most of its blood flow (coronary blood flow).
dromotropic -
Referring to conduction velocity of action potentials through the AV node. Something that increases the rate of conduction through the AV node has a positive _______ effect.
end-diastolic volume (EDV)
The volume of blood in the left ventricle at the _______. _______ is a reflection of ventricular filling which is a function of the muscle pump, thoracic pump, venous vasoconstriction, and cardiac output. _______ is measured in mL.
endocardium -
The smooth inner lining of the heart.
epicardium -
The outer layer of the heart.
fibrous ring -
The non-conductile and non-contractile fibrous skeleton that separates the atria and the ventricles. The _______ anchors the four heart valves, serves as an attachments point for cardiac muscle as well as the aorta and pulmonary arteries.
fick equation
An equation used to calculate oxygen consumption (VO2) which is the product of total blood flow (Cardiac output) and the amount of oxygen consumed per unit of blood flow (av-O2 difference). VO2 (mL/min) = Q (dL/min) x a-O2 difference (mL/dL)
gap junctions -
Small gaps in the cell membrane of cardiac muscle cells that allow movement of ions from one cardiac muscle cell to the next. _______ allow for the property of conductivity between cardiac muscle cells.
hematocrit (Hct) -
The percentage of whole blood that is red blood cells.
hemoglobin (Hb) -
The oxygen carrying molecule of the red blood cell. One (1) gram of Hb carries 1.34 mL of oxygen when the Hb is fully saturated.
