A&P 8 Flashcards

Terms Definitions
The lining of the heart
endocardium
Which circulation system transports oxygen-poor, carbon dioxide rich blood to the lungs for oxygenation and carbon dioxide unloading?
pulmonary circulation
What regulates blood flow into capillary beds?
arterioles
What is pericarditis?
inflammation of the pericardium
AV valve with two flaps
mitral valve
The blood flow thru capillary networks is slow and intermittent and is known as what?
vasomotion
All blood vessels except what have three layers:
capillaries
What does arteriovenous anstomoses connect?
arterioles and venules
Prevents backflow into the left atrium
mitral valve
Prevents backflow into the right atrium
tricuspid valve
What part of the nervous system increases the heart rate and force of the beat?
sympathetic
What does the pulmonary circulation pump side of the heart carry in the blood?
carbon dioxide
What consists of noncontractile cardiac cells specialized to initiate and distribute impulses thru out the heart so that it depolarizes and contracts in an orderly, sequential manner?
cardiac conduction system
How many pulmonary veins enter the left atrium and deliver oxygen-rich blood from the lungs to the left atrium?
4
What cradles the anterior interventricular artery, marks the anterior position of the septum separating the right and left ventricles?
anterior interventricular sulcus
What are the most common type of capillaries?
continuous
What varies directly with CO (cardiac output), peripheral resistance, and blood volume?
blood pressure
What is the phenomenon called that is particularly common in the heart when a coronary vessel is partially occluded where the number of blood vessels in the region increases and existing vessels enlarge?
angiogenesis
What is the internal resistance to flow that exists in all fluids and is related to the thickness or "stickiness" of a fluid?
blood viscosity
What are alternate blood pathways in case one branch is cut or blocked by a clot, provided by anastomoses called?
collateral channels
Blood is brought toward the heart by what?
veins
What carries blood to tissue cells and are exchange sites?
capillaries
What is found on capillaries and aid in the exchange between the blood and interstitial fluid?
clefts
Blood is carried away from the heart by what?
arteries
What is the loosely fitting connective tissue part of the pericardium called?
fibrous pericardium
Prevents backflow into the right ventricle
pulmonary semilunar valves
What is the disease process in which the body's blood vessels become increasingly occluded by plaques?
atherosclerosis
Prevents backflow into the left ventricle
aortic semilunar valve
What structure is replaced by an artificial pacemaker?
SA node
What returns oxygen-poor blood from body areas below the diaphragm?
inferior vena cava
What does the term diastole refer to?
relaxation period
What are all events associated with the blood flow thru the heart during one complete heartbeat referred to as?
cardiac cycle
What are the actual pumps of the heart?
Ventricles
Complete blockage of what leads to tissue death and heart attack?
coronary artery
What is the shortest circulation and supplier of functional blood supply of the heart called?
coronary circulation
What is normal CO (cardiac output)?
5.0 to 5.5 L/minute
What are the most permeable capillaries?
sinusoids (wide, tortuous channels)
What is orthostatic hypotension?
temporary low blood pressure and dizziness when suddenly arising
What occurs when the heart is so inefficient that it cant sustain adequate circulation, usually caused by myocardial damage, such as heart attack?
cardiogenic shock
What is the usual result of pressures over 160 mm Hg, which dramatically increases brain capillary permeability?
cerebral edema
How is blood flow related to the peripheral resistance in the systemic circulation?
inversely proportional
What interferes with depolarization by lowering resting potential and may lead to heart block and cardiac arrest?
excessive K+ levels (hyperkalemia)
Describe what happens in the cardiac cycle during the QRS wave
depolarization of ventricles
what happens in the cardiac cycle during the T wave
repolarization of ventricles
What are pacemaker potentials or prepotentials?
spontaneously changing membrane potentials
What is it called when a region of heart muscle is deprived of blood?
ischemic
What is the counterpart for the anterior interventricular sulcus?
posterior interventricular sulcus
Which side of the heart is the systemic circuit pump?
Left side
Where is the most serious damage done in myocardial infarction?
left ventricle
What node has the highest rate of discharge and provides the stimulus for contraction?
SA node
Where do arterial anastomoses occur?
around joints, abdominal organs, the brain and the heart
What collects the small net loss of fluid and protein into the interstitial space and returns it to the cardiovascular system?
the lymphatic vessels
What controls the heart's stroke volume during 'resting' periods?
venous return (end diastolic volume)
What is the neural center - the cluster of neurons in the medulla - that oversees changes in the diameter of blood vessels called?
the vasomotor center
What are the least permeable capillaries and why?
continuous capillaries, which lack pores
What do vascular shunts connect?
terminal arteriole and venule at opposite ends of a capillary bed
What is autoregulation usually controlled by?
oxygen deficits and accumulation of local metabolites
Hormones that affect blood pressure are:
Adrenal medulla hormones - norepinephrine and epinephrine; atrial natriuretic peptide (ANP); ADH(vasopressin); angiotensin II
By which week is the fetal vasculature functioning?
the 4th week
What are low-resistance pathways that conduct blood from the heart to medium sized arteries referred to as?
elastic arteries or conducting arteries
How do water soluble substances move across capillary walls?
thru clefts or fenestrations
What pace is set by the AV node (junctional rhythm)
40-60 bpm
What is the myocardium reinforced internally by?
fibrous skeleton of the heart
What provides the functional blood supply of the heart?
right and left coronary arteries
What is prolonged coronary blockage called?
myocardial infarction, aka heart attack
what are pectinate muscles?
a smooth-walled posterior part and an anterior portion inside the right atrium, ridged by bundles of muscle tissue
If the left side of the heart fails what occurs?
pulmonary congestion
Where are sinusoid capillaries found?
in the liver, bone marrow, lymphoid tissues and some endocrine organs
How do kidneys regulate low bp?
releasing renin, which triggers the formation of angiotensin II (a vasconstrictor) and release of aldosterone
How does aldosterone affect blood pressure?
enhances renal reabsorption of sodium and prods posterior pitutiary to release ADH, which promotes more water reabsorption, causing both blood volume and blood pressure to rise
Where is systemic blood pressure highest and lowest?
highest - aorta
lowest - venae cavae
What are the 3 most important factors that affect SV (stroke volume)
preload; contractility; and afterload
What is the contractile strength achieved at a given muscle length called?
contractility; The strength of each contraction of the heart muscle
What kind of pump does the right side of the heart function as?
pulmonary circulation pump
What does the right ventricle do?
pumps blood into the pulmonary trunk
How do veins serve as blood reservoirs?
They are usually only partially filled
What is composed largely of loosely woven collagen fibers that protect and reinforce the vessel. It also anchors the vessels to surrounding structures
the third layer, or tunica externa
How does the cardiovascular center integrate blood pressure control?
by altering cardiac output and blood vessel diameter
What is usually in charge of heart rate?
cardioinhibitory center in the medulla
In what 3 ways do veins adapt to venous return to overcome low pressure?
respiratory pump-breathing which squeezes veins & forces blood toward heart;muscular pump-as skeletal muscles surrounding deep veins contract/relax, they 'milk' blood toward heart;layer of smooth muscle around veins that constricts under SNS control
Why are veins called capacitance vessels and blood reservoirs?
because of their large blood supply; up to 65% of the body's supply
The cardiac veins join together to form an enlarged vessel called what and empties blood where?
coronary sinus, which empties the blood into the right atrium
what heart sound is created by blood turbulence associated with the closing of the atrioventricular valves soon after ventricular systole begins
The first heart sound (lubb)
What is the internal partition that divides the heart longitudinally called?
The interatrial septum (separates the atria)and the interventricular septum (separates the ventricles)
What is the left AV valve called, that consists of 2 cusps of endocardium?
mitral or bicuspid valve
Where is the steepest drop in BP?
in the arterioles, where resistance is greatest
How is vasomotor tone achieved in the arterioles?
by impulses transmitted by the vasomotor center, along sympathetic efferents called vasomotor fibers and innervate the smooth muscle of blood vessels, (mainly arterioles)
How does the indirect renal mechanism (renin-angiotensin mechanism) alter blood volume?
kidneys release renin into blood which triggers a series of reactions that produce angiotensin II which increasing peripheral resistance via its potent vasoconstriction properties
What is the function of tissue perfusion?
delivery of oxygen and nutrients to and removal of wastes from, tissue cells, gas exchange in the lungs; absorption of nutrients from digestive tract; urine formation in the kidneys
What are the 3 phases of the cardiac cycle?
atrial systole, ventricular systole, and the relaxation period.
What 2 valves are each composed of 3 pocketlike cusps and guard the bases of the 2 large arteries leaving the ventricular chambers?
pulmonary and aortic semilunar valves
What do the 2 AV valves prevent?
backflow into the atria when the ventricles are contracting
What is attached to each AV valve flap?
tiny white collagen cords called chordae tendineae aka heart strings
Why would an artery have a thicker tunica media layer?
because they are more active in vasoconstriction and less idstensible
What 3 functions does blood flowing thru the skin provide/
1) supplies nutrients to the cells 2) aids in body temp regulation 3) provides a blood reservoir
What are the 4 chambers of the heart?
2 superior atria and 2 inferior ventricles
The act of listening to sounds within the body is called what and what instrument is usually used?
auscultation, and it is usually done with a stethoscope
When do chemoreceptors in the aortic arch and large arteries of the neck transmit impulses to the cardioacceleratory center, to increase cardiac output and to the vasomotor center, which causes reflex vasoconstriction?
when the oxygen content or pH of the blood drops sharply or the CO2 levels rise
What is autoregulation in the brain controlled by?
primarily by a drop in pH and by myogenic mechanisms
What is the pressure that must be overcome for the ventricles to eject blood?
afterload - refers to the resistance the left ventricle encounters as it tries to eject blood to the body
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