Ch 15 Human Physio
Approximately what volume of blood passes through the heart each day?
7,000 liters
What is vasoconstriction?
A decrease in the diameter of a blood vessel
Complete the sentences describing the events that occur during an action potential.
An action potential will not occur unless the membrane potential at the trigger zone (the initial segment of the axon) reaches a level called threshold. When threshold is reached, voltage-gated sodium channels of the initial segment open briefly, allowing to sodium diffuse into the cell. As these ions enter the cell, the cell membrane undergoes depolarization with the membrane potential increasing to a peak of approximately +30mV. As the peak of the action potential is reached, the sodium channels close and the voltage-gated potassium channels open, allowing these ions to diffuse out of the cell. As cations leave the cell, the membrane potential at that part of the membrane is reestablishing resting membrane potential. This phase of the action potential is called repolarization. The membrane potential actually dips lower than -70mV because the potassium channels do not close quickly enough. This phase is called hyperpolarization.
What is vasodilation?
An increase in the diameter of a blood vessel
Semilunar valve
Aortic valve Pulmonary valve
You are listening to a patient's heart. You place your stethoscope between the 5th and 6th ribs. What sounds are you hearing?
Apical heartbeat
Complete each statement by using the appropriate word or phrase from the list. Then place the statements in the order of an action potential repolarization event.
As the membrane potential rises towards zero, the voltage-regulated sodium channels begin closing which in turn reduces the sodium movement to the cell. With membrane potentials approaching +35 mV, the voltage regulated potassium channels become fully activated. Through the activated channels, potassium now flows outward causing the membrane to repolarize back toward the RMP (resting membrane potential). With a longer duration of activation than sodium channels, the potassium channels allow for a greater movement of potassium to the extracellular fluid causing a short period of hyperpolarization.
Mitral valve
Between the left atria and ventricle
Aortic valve
Between the left ventricle and the aorta
Tricuspid valve
Between the right atria and ventricle
Pulmonary valve
Between the right ventricle and the pulmonary trunk
Why does reabsorption dominate the venule end of the capillary?
Blood pressure has decreased but colloid osmotic pressure has remained the same and attracts water into the capillary.
What are the papillary muscles connected to?
Chordae tendineae
What prevents the atrioventricular valves from inverting into the atrium against the pressure of blood from the ventricles?
Chordae tendineae and papillary muscles
Contraction of the right ventricle leads to the what action?
Closing of the tricuspid valve
What factors influence capillary exchange?
Colloid osmotic pressure Hydrostatic pressure
How does the mitral valve close?
Contraction of the left ventricle forces blood against the valve and closes the valve.
By which mechanism do compounds like oxygen, carbon dioxide, and fatty acids move through cell membrane?
Diffusion
Place in order the three layers of the heart wall, listing the deepest layer first to superficial.
Endocardium, myocardium, epicardium
The SA node relays nerve impulses into the AV bundle of the interventricular septum, and the AV node is responsible for the rhythmic contractions of the heart.
False
What process is described as the movement of molecules across a membrane under the influence of hydrostatic pressure?
Filtration
Hydrostatic pressure is highest at the arteriole end of a capillary network. What does that mean in terms of capillary exchange?
Filtration determines capillary exchange here.
What molecule would be unable to diffuse through a cell membrane?
Glycogen
What organ is housed within the thoracic cavity?
Heart
Why is filtration the dominant exchange process at the arteriole end of a capillary?
Hydrostatic pressure is greater at this end.
When does the aortic semilunar valve close?
It closes as the ventricles relax.
What chamber of the heart do the pulmonary veins drain into?
Left atrium
What structure empties blood into the left ventricle?
Left atrium
Which chamber of the heart receives oxygen-rich blood from the lungs?
Left atrium
Which is the correct pathway of blood flow between the lungs and the body?
Left atrium - mitral valve - left ventricle - aortic valve - aorta
Supplies blood to the systemic circulation to deliver oxygen to tissues
Left side of heart
Blood flows from the left atrium into what chamber of the heart?
Left ventricle
What chamber of the heart pushes blood into the aorta?
Left ventricle
What is the function of lymphatic capillaries?
Lymphatic capillaries return excess tissue fluid forced from the capillary networks back to the venous system.
Atrioventricular valve
Mitral valve Tricuspid valve
Which of the following correctly matches the valve to its function?
Mitral valve—permits one—way blood flow from the left atrium to the left ventricle
Select all the mechanism(s) that help in movement of substances through capillary walls.
Osmosis, Filtration, Diffusion
When blood reaches the tissue, what gases are typically exchanged via diffusion?
Oxygen and carbon dioxide
Blood colloid osmotic pressure is primarily determined by what substance?
Plasma proteins
Why do plasma proteins typically remain in the bloodstream and not enter the tissue fluids?
Plasma proteins are too large to diffuse out of the capillaries.
Where is the heart located in relation to other structures?
Posterior to the sternum
Cells of the conducting system in the heart are more sensitive to which ion?
Potassium
What controls blood flow into the capillary network?
Precapillary sphincters
Which valve is found between the right ventricle and the pulmonary trunk?
Pulmonary valve
Which are the two semilunar valves?
Pulmonary valve Aortic valve
Where does the blood that enters the left atria come from?
Pulmonary veins
Supplies blood to the lungs for exchange of respiratory gases
Right side of heart
What chamber of the heart pumps blood into the pulmonary trunk?
Right ventricle
the pacemaker or __ indicates the cardiac cycle
SA node
In an ECG pattern, the PQ interval indicates how long it takes for the cardiac impulse to travel from the
SA node through the AV node.
What vessels bring blood to the right atrium?
Superior vena cava Coronary sinus Inferior vena cava
What controls the relaxation and contraction of the precapillary sphincters?
The availability of oxygen and nutrients to the tissues surrounding the capillary network
What is the pulmonary circuit?
The circuit which carries oxygen-poor blood to the lungs
How does the tricuspid valve close?
The contraction of the right ventricle forces blood against the cusps, which closes the valve.
What is the pericardium?
The covering that encloses the heart
What is hydrostatic pressure?
The force that pushes water into and out of capillaries
What is filtration?
The forced movement of compounds through a membrane via hydrostatic pressure. Diffusion is the natural way it wants to go, but filtration forces it one way
How does the aortic semilunar valve open?
The left ventricle contracts and forces blood through the valve.
The wall of the left ventricle is thicker than the wall of the right ventricle. Why?
The left ventricle has to pump blood farther.
What is the myocardium?
The middle layer of heart tissue composed mostly of cardiac muscle
What is the function of the systemic circuit?
The systemic circuit carries oxygenated blood from the heart to the rest of the body.
What are the ventricles?
The thicker-walled, inferior chambers of the heart
The blood from the right ventricle travels only to the lungs. This physiological attribute explains what anatomical feature?
The wall of the right ventricle is thinner than the wall of the left ventricle.
What is the interatrial septum?
The wall that separates the right and left atria
What is the status of pressures in capillary beds?
There is a net inward pressure at the venule end.
What are the right and left atria?
Thin-walled upper chambers of the heart that receive blood returning to the heart
Describe the aortic valve?
Three semilunar cusps at the base of the aorta
What is the function of the chordae tendineae and papillary muscles?
To prevent the AV valves from inverting into the atria due to the pressure of blood
True or false: The cardiovascular system includes the heart and blood vessels.
True
How does excess tissue fluid return to venous circulation?
Via lymphatic capillaries
Precapillary sphincter
a band of smooth muscle fibers that encircles the capillaries at the arteriole-capillary junctions and controls blood flow to the tissues
the resting membrane potential includes
a high concentration of sodium ions outside the cell membrane and a high concentration of potassium ions inside the cell membrane
signals within the body
action potentials are very fast and can be targeted to a single location and hormones have a very wide response in multiple locations
The left ventricular contraction forces blood into the ___ a large artery.
aorta
blood pressure is detected by sensors at
aorta and carotid arteries
The ___ valve is located between the left ventricle and the aorta.
aortic
The inferior end of the heart that tapers to a blunt point immediately above the diaphragm is called the _____ of the heart.
apex
action potentials
are a form of signaling within the body, involve ions, create voltage, occur in most living organism
Small arteries called ______ are capable of vasoconstriction and vasodilation.
arterioles
hydrostatic pressure is higher
at the begninning of the capillary
the upper chambers of the heart
atria
Blood passes from the left _____ through the mitral valve into the left _____ which then pushes blood out to the _____.
atrium, ventricle, aorta
structure which is used to communicate blood pressure to the nervous system
baroreceptor
The _____ of the heart is the superior border that is a relatively flattened area with several vessels attached.
base
The region of the heart to which the great vessels are attached is called the ______.
base
action potential
begins in the atria and spreads to the ventricle and in the ventricles causes blood to flow through the aorta and pulmonary artery
Where is the mitral, or bicuspid, valve located?
between left atrium and left ventricle
Where is the tricuspid valve located?
between right atrium and right ventricle
The apical heart beat can be detected by feel or by listening what location?
between the 5th and 6th ribs
the primary concern for the brain is
blood pressure
If all of your blood vessels were to vasodilate at the same time, what would happen?
blood pressure would fall dangerously low
Leukocytes
can move within the various tissues, are NOT found almost entirely in the blood stream, CAN leave the bloodstream
blood proteins
cannot leave the bloodstream, are large complesx molecules, are the primary component of the osmotic pressure, and draw water back to the bloodstream from cellular space by osmosis
The blood vessels that are the site of exchange between the blood and the tissue fluid are the ______.
capillaries
The vessels that are the site of exchange between the blood and the tissue fluid are the .
capillaries
What vessels allow for exchange of oxygen, carbon dioxide, and nutrients between the blood and tissue fluid surrounding cells?
capillaries
where is the most critical blood pressure in the body and what options do you have to control it
capillaries, heart rate (stroke volume), sympathetic and parasympathetic impulses, vasoconstriction/vasodialation, recapillary sphincters
The vital function of gas and nutrient exchange between the blood and tissue fluid and cells takes place in a , a small vessel.
capillary
what ultimately is the objective of your cardiovasular system
capillary exchange
waste that is found within the bloodstream
carbon dioxide
epinephrine
causes rapid heart rate increase, will cause airways to open for breathing, will increase brain alertness, increase muscle preparedness
the electrical conducting system of the heart
causes the heart to contract, conducts action potentials, can be studied in an EKG, and keeps the proper coordination in heart chamber contractions
where are items in bloodstream being transported to
cells
What are the papillary muscles connected to?
chordae tendineae
During ventricular systole, blood in the left ventricle is squeezed upward. This results in _______ of the _______.
closing; mitral valve
The pressure in the capillary due to presence of impermeant solutes is called the ___ osmotic pressure.
colloid
the left side of the heart
contains the bicuspid valve and pumps blood through the body tissues
osmotic pressure (oncotic)
created by blood proteins
parasympathetic action potentials
decrease heart rate and reach the SA node
Blood pressure ______ as the distance from the heart increases.
decreases
In an ECG pattern, the P wave is caused by
depolarization of atrial muscle fibers.
The heart is housed within the mediastinum and rests on the____, a muscle.
diaphragm
the role of cardiovascular system is transportation and delivery. which of these bests explains the importance of blood pressure in this role
diffusion
glucose is required for cellular respiration, which system(s) provide it to the cells
digestive and cardiovascular
the primary function of capillaries
echange nutrients with cells
one of the hormones of the adrenal glands
epinephrine
when a sense of danger is perceived by the brain
epinephrine is released by the adrenal glands, flight or fight response, epinephrine will stimulate heart for rapid heart rate increace
True or false: The cardiovascular system maintains blood flow to all tissues equally all the time.
false
True or false: As oxygen levels in a tissue decrease, the precapillary sphincters contract.
false: Reason: As oxygen levels in the tissue decrease, precapillary sphincters relax in order to let more oxygenated blood into the tissue.
Blood pressure generated by the ventricular contraction provides the force for __________.
filtration
The process of ___ is dependent on blood pressure and is the force which pushes fluid out of the capillary.
filtration
hydrostatic pressure
fluid pressurea dn created by heart contration
How many hollow chambers are found in the heart?
four
cellular respiration
goal is to produce ATP and produces co2 as waste
Blood pressure is ________ at the arteriolar end of a capillary than at the venular end.
greater
blood pressure is determined by
heart rate, vasodialation, vasoconstriction, epinephrine
What pressure is exerted by the blood to push ions and other small molecules through the capillary walls?
hydrostatic pressure
the increace of aterial blood pressure over the normal levels (high blood pressure) can cause and why?
increaced cellular and intersatial fluid levels (swelling) because of increased hydrostatic pressure
sympathetic action potentials
increase heart rate and reach the SA node
Due to oxygen and nutrient needs during exercise, blood flow is ____ to skeletal muscles and ____ to the digestive tract.
increased; decreased
The wall that separates the upper chambers of the heart is the _____, and the wall that separates the lower chambers is the _____.
interatrial septum; interventricular septum
during open heart surgery, the heart is covered in and the chambers filled with potassium solution. this is to keep the heart from beating during the surgery. why does this work?
interferes with repolarization of heart tissue
The colloid osmotic pressure of the blood is greater than the hydrostatic pressure of the tissue fluid at the venule end of the capillary. This causes a net fluid movement ______ the blood.
into
depolarization
is caused by positive ions rushing into the cell and results in reversing of the charges from positive to negative across the membrane
the fluid leaving and returning to the bloodstream directly at the capillary, overall
is greater leaving
the sodium/potassium pump
is used to return ions to original location and moves ions to areas of higher conentration
why does rbc percentage have such a wide range as a possibility (40-55%)
it allows blood oxygen levels to be very tightly controlled regardless of outside conditions (ex altitude)
as action potentials spread throughout the cardiac conduction system. when they reach the AV node there must be a short delay before it continues. what would be the best explanation for that
it allows for blood to flow from the atria and into the ventricles before they begin to depolarize
why is blood pressure such an important factor in survival
it determines the hydrostatic pressure within the capillaires
The heart in its pericardium is located medial to two __
lungs
the excess from the previous question is handled by
lymph vessels
The heart is located in the _______ and is _____ to the diaphragm.
mediastinum; superior
this part of the brain is responsible for basic blood pressure and heart rate
medulla oblongata
The left atrioventricular valve is also called the ____ valve.
mitral or bicuspid
The ______ valve is located at the opening into the left ventricle and the ____ valve is located at the exit from the left ventricle.
mitral, aortic
the heart consists of
myocardium
the resting membrane potential is
negative inside and positive outside the membrane
is the blood able to flow to all tissues fully at all times
no
Innervation of smooth muscle in the arterial and arteriolar walls is by ______ fibers.
only sympathetic
an action potential begins by
opening of sodium channels
action potentials begin by
opening of voltage-activated sodium channels
the net flow of fluid at the end of the capillary is
out from plasma to the cells
potassium ion channels opening
outside of cell becomes more positive and repolarization
The left atrium receives ______ blood from the ______.
oxygen-rich; pulmonary veins
The small clumps of muscle to which the chordae tendineae are attached are called the ______ muscles.
papillary
when blood pressure drops, the reaction would be to
parasympathetic impulses decrease and sympathetic impulses increase
covering of the heart
pericardium
why must there be both a systemic and pulmonary circuit of the cardiac cycle
pressure cannot be maintained sufficiently in a single circuit and one must exchange with the cells the other with the lungs
closing of heart valves
prevents backward blood flow and causes lubb and dubb
Deoxygenated blood travels from the heart to the lungs via the ______ circuit.
pulmonary
When the right ventricle contracts, blood is pushed through the _____ valve into the pulmonary trunk.
pulmonary
Blood leaving the right ventricle flows into the ______.
pulmonary trunk
In capillary exchange, plasma colloid osmotic pressure favors _____ and capillary blood pressure favors ______.
reabsorption; filtration
In an ECG pattern, the T wave is caused by
repolarization of ventricular muscle fibers.
membrane potential
repolarization= potassium rushing out of cell
waste products of cellular respiration and other processes are removed from the cells and body by
respiratory system, cardiovasuclar system, urinary system
Blood from the superior and inferior vena cavae and the coronary sinus flow into the ______.
right atrium
Which heart chamber receives blood that is low in oxygen?
right atrium
A blood cell is traveling in the inferior vena cava and approaches the heart. Rank the following structures in the order in which the cell encounters them.
right atrium, right ventricle, pulmonary trunk, pulmonary artery, lungs
The pulmonary circuit receives blood from the ______ side of the heart and the systemic circuit receives blood from the ______ side of the heart.
right, left
osmotic pressure is higher
roughly equal throughout
the SA node
sends action potentials across the atria and sends action potentials after sodium channels open
action potentials which convey pressure information TO the brain are carried along
sensory fibers
small molecules can leave the capillaires and enter intersatial fluid through
sinusoids (pores)
A nurse wants to measure a patient's blood pressure. She will have to use a(n)
sphygmomanometer
which of these is a property of cardiac muscle. why does this occur?
spontaneous depolarization and intrinsic contraction SA node contains ion channels that leak
which of these is a property of cardiac muscle and why
spontaneous depolarization and intrinsisc contraction because SA node contains ion channels that leak
red blood cells
survive for 120 days on average
if your heart rate is 120 BPM during exercise which of these would be true
sympathetic impulses are dominant
if your heart rate is at 120 BPM during exercise which of these would be true
sympathetic impulses are dominant
Oxygenated blood travels from the heart to the rest of the body via the ______ circuit.
systemic
the QRS complex of an EKG represents
the onset of ventricular systole
if there is a heart defect that includes a small hole in the septum of the heart which of these would be most likely
there may be a decrease in the amount of oxygen in the bloodstream leaving through the aorta
The right atrioventricular valve is also called the _____ valve.
tricuspid
Blood passes from the right atrium, through the ___ valve into the right ventricle. The right ventricle contracts and pushes blood through the pulmonic valve into the pulmonary ____, which delivers blood to the lungs.
tricuspid, trunk/arteries
True or false: Blood plasma proteins are too large to pass through the capillaries and into the tissues.
true
True or false: More fluid leaves the capillaries than is reabsorbed.
true
Contraction of the smooth muscle in the tunica media of blood vessels causes .
vasoconstriction
Sympathetic stimulation of vascular smooth muscle causes ______.
vasoconstriction
List three ways the brain can control blood pressure and blood flow to different regions of the body?
vasoconstriction/vasodilation, sphincters, and blood pressure
Relaxation of the smooth muscles in the tunica media of blood vessels causes ______.
vasodilation
How is it possible your blood vessels have enough room for 8 liters of blood but we only actually have 5 liters of blood?
while fully vasodialated vessels might take up a larger volume, they would never all be dialated at the same time and a certain percentage of vessels are always vasoconstricted reducing the total volume
