Lab Quiz #2
If the tipe of the heart pointed at the midline of the chest, then the 2 intersecting lines would cross at about ...
90 degrees
Effect of negative pressure on veins around the heart
Negative pressure pulls blood to the venis around the heart
Pacemaker of normal healthy heart?
Sinoatrial node
A single "twitch" contraction of skeletal muscle is produced...
by a single action potential in a group of muscle fibers
A contraction of the ventricles increases the pressure of the blood inside the ventricles and...
closes the atrioventricular valves to produce the "lub" heart sound
"lub" sound
closing AV valves when ventricles contract; around QRS complex
Upward deflection of the heart sound line tracing indicates...
closing of the AV vlaves
Downward deflection of the heart sound line tracing indicates...
closing of the semi-lunar valves
Oxygen and CO2 exchangetake place between teh blood and air only across the walls of the...
alveoli
Lungs and walls of the thoracic cavity...
are connected by the pleural sac
During the lab, electrical stimuli were applied to the ventricle of the frog heart...
at different times throughout the cardiac cycles.
AV valves open when...
atrial pressure is greater than ventricular
Decreased partial pressure of oxygen means...
decreased amount of oxygen bound to hemoglobin
Pulmonary capillaries close if the arterial blood pressure...
decreases
When blood travels against gravity, the pressure...
decreases
Effect of acetylcholine on heart rate...
decreases heart rate (parasympathetic nervous system)
Changing from standing to lying...
decreases tidal volume.
Systolic blood pressure is...
higher when standing
Systolic blood pressure...
highest blood pressure recorded from the systemic arteries
Amplitude of the ECG indicates...
how far the heart lies off the midline
Baroreceptors are located...
in the carotid artery
Cardiovascular control center is located...
in the medulla of the brain
Heart is located...
in the thoracic cavity
Increase in arterial blood pressure
increase baroreceptor signal to increase parasympathetic nervous system activity
Inhalation and heart rate and stroke volume
increase in heart rate and decrease in stroke volume
Increasing teh amount of blood returning to the heart would...
increase the end diastolic volume
Diaphragm and intercostal muscle contract to...
increase the volume of the thorax
Mean tidal volume after breathing through a tube...
increased (increase in anatomical dead space)
If the amount of blood passing through the circulatory system increases by heart rate remains constant, the amount of blood leaving during each contraction...
increases
Effect of adrenaline on heart rate and contraction amplitude/cardiac output
increases heart rate and contraction amplitude/cardiac output
Effect of adrenaline on blood pressure
increases rate at which blood enters arteries = increased blood pressure
Maintaining constant alveolar ventilation after 200mL increase in anatomical dead space....
increasing tidal volume by 200 mL
Hemoglobin is found...
inside red blood cells
Pressure of blood at heart...
is greater than the blood pressure in the head
In a relaxed heart the blood pressure in the aorta...
is greater than the blood pressure in the left ventricle
Air is the anatomical dead space...
is not available for gas exchange, remains constant, and is the first to leave on exhalation
High transmittance value indicates
large amount of oxygen bound to hemoglobin
The duration of the cardiac potential is...
longer than the action potential recorded from skeletal muscle fiber
In a person lying down, if more capillaries are open, the tidal volume will be...
lower than when standing because increased surface area allows more efficient gas exchange.
Blood pressure lying down
means blood pressure in heart will be about the same in the head
At the tissues, a low pH pushed the oxygen dissociation curve to teh right so that...
more oxygen is released which leaves less oxygen bound to hemoglobin
Decreasing pH of the blood...
moves oxygen dissociation curve to the right (lower transmittance value); less oxygen bound to hemoglobin
Hydrogen ions bind to the beta-chains of hemoglobin and decrease the affinity of hemoglobin for oxygen. Therefore, lowering the pH:
moves the oxygen curve to the right
"dupp" sound
semilunar valves close and ventricles relax; T wave
Which takes place first after the ventricles contract?
the AV valves close
If the amount of venous blood returning to the heart increases past maximal tension?
the EDV is greater but stroke volume is less
in ECG, depolarizing phase of the action potential is associated with...
the QRS complex
What happens to the amount of tension produced by the heart if it is stretched beyond 15 mm?
the amount of tension decreases
On the left side of the heart, the semilunar valves open when...
the blood pressure in the left ventricle is greater than blood pressure in the aorta
The rhythmic upward and downward deflection the upper line on the computer screen indicate...
the cardiac cycle.
The upward deflection of the lower line on the computer screen indicates...
the electrical stimuli delivered to the ventricle
The length of the cardiac muscle fibers will increase if...
the end diastolic volume increases (means increased venous return has occurred)
Packemaker for the human heart is located in...
the heart
The prolonged refractory period during the action potential ensures that...
the heart has time to fill with blood before the next contract; prevent fibrilliation
The heart cannot go into tetanus and continue to pump because...
the heart must rest between contractions to fill with blood.
The amount of tension produced by a contraction of a striated muscle fiber depends upon...
the length of the sarcomere, and therefore the length of the muscle
Blood flow to a group of alveoli will decrease if...
the level of oxygen in the alveoli decreases.
If the heart were in the midline of the chest, then the distance between teh heart and each recording electrode in the lead I orientation would be...
the same.
In the human heart, ventricles relax and...
the semilunar valves close and produce the 'dup' heart sound
A palpable pulse is produced by...
the stretching of arteries that are the neart the body surface
Blood pressure increased by activity of...
the sympathetic nervous sytem
Maximum value for blood pressure is called...
the systolic pressure
Pacemaker cells in the SA node produce action potentials in ventricle fibers...
via the AV node
Pacemaker cells in the SA node produce action potentials in the atrial fibers...
via the gap junctions
What happened when the volunteer laid down and tidal volume decreased...
volume of air entering the alveoli decreased.
Alveolar ventilation
volume of air that enters the alveoli
Anatomical dead space is...
volume of air trapped in the airways
Change in metabolic rate when breathing through a tube...
was insignificant
Blood pressure (as moved towards brain)...
will decrease
During a normal cardiac cycle the ventricles contract...
after the atria contract.
Time delay between R-wave and swelling of the finger
0.25 seconds
Maximum recorded tension...
15 mm
Breathing normal and then inhale 50+mL of fresh air...
50 mL+ of fresh air in the alveoli
Angle of heart...
65 degrees
Which muscle fibers are banded/striated in appearance?
Cardiac and skeletal muscles
If rate of arterial blood loss is constant what would acetylcholine do to blood pressure?
Decrease blood pressure
What does cooling do to rate of channels opening and closing?
Decreases rate of channels opening and closing and slows pacemaker activity/heart rate
Effect of cooling on rate of enzymic action?
Decreases rate of enzymic action
One hemoglobin can have...
FOUR molecules of oxygen
What strategies are used by the cardiovascular system to ensure that cardiac muscles are over stretched?
HR increases and EDV remains within reasonable limits
Effect of cooling on heart rate?
Heart rate decreases
If stretching increases tension, what would be the effect of a stronger contraction on the stroke volume?
Increases stroke volume (EDV-ESV)
What happens to the length of the muscle fibers if EDV is increased?
Muscle fibers will lengthen
Effect of acetylcholine on membrane potential?
Opens potassium channels on pacemaker cells, hyperpolarizes membrane, moves if further from threshold so action potentials/heart contractions occur at a slower rate)
When was an extra contraction produced?
When the stimulus was applied after the ventricle had contracted normally, when the ventricle was relaxing and filling with blood.
In the ventricle of the human heart, the deploarizing phase the action potential is associated with...
QRS complex
Cardiac output =
Stroke volume x heart rate OR contraction amplitude x frequency
repolarization of ventricles
T wave
Blood pressure decreased by...
activity in the parasympathetic nervous system
What organ is supplied by carotid arteries?
The brain
What happens to surface area for gas exchange when a person lies down?
The surface for gas exchange increases when the person lies down
Alveolar ventilation calculation
Tidal volume - dead space
What is the maximum amount of tension created by a single contraction?
When the muscle is at its resting length, where the maximum number of crossbridges can be made within the sarcomeres
During the cardiac cycle, ventricular contraction is produced by...
a single action potential in, and a contraction of, all ventricular myocytes.
Lowest blood pressure of standing person...
above the heart
Pulmonary capillaries will most likely be closed...
above the heart (where blood pressure is lowest).
The parasympathetic nervous system secretes...
acetylcholine on the SA node to slow the heart rate
pH below 7 means...
acidic
the ECG measures...
action potentials in the atria and the ventricles
Atria contract...
before ventricles
Fluid circulating materials around the body is called...
blood
When blood flows from the ventricle to the aorta...
blood pressure in the aorta increases
Maintaining constant amount of air with increased dead space...
breathing deeper and increasing tidal volume
Cells make hydrogen ions because they can produce...
can produce lactice acid and carbon dioxide (forms H2O and bicarbonate ions)
The sympathetic nervous system secretes...
norepinephrine onto the SA node to increase the heart rate
The ECG is composed of P-wave, QRS complex, and a T wave. They each occur...
once during each cardiac cycle.
Prolonged refractory period in cardiac action potential is produced by..
open (L-type) voltage-gated calcium channels
When the AV valves are closed, further contraction of the ventricles increases the pressure of inside the ventricles and...
opens the semilunar valves
The amount of oxygen that binds to hemoglobin depends upon:
pH level; temperature; amount of oxygen available
The heart lies in the thorax with its long axis...
pointing downward, at some angle between horizontal and vertical
Partial pressure of oxygen is ...
portion of barometric pressure produce by oxygen
Lead I orientation...
signals recorded from both wrists
Lead II orientation...
signals recorded from wrist and ankle
Rhythmic contractions of the healthy human heart initiated by action potentials produced by cells in...
sinoatrial node
Largest amount of blood returns to the heart when...
someone inhales
Blood is at its lowest pressure in
the veins
If extra ventricular contractions were produced when the ventricle was relaxing, this means that...
the ventricle filled with some blood before the next contraction.
At the alveloi diffusion of gases between air and blood is facilitated by...
thin exchange barrier, large surface area, deoxygenated blood in the pulmonary arteries
The heart is located...
to the left of the midline
Delay indicates the time in which the increase in arterial blood pressure is detected after action potential in the...
ventricles
SL valves open when...
ventricular pressure is greater than arterial pressure