Heart beat - class-IX
Description: heart beat | |
Number of Questions: 85 | |
Created by: Akash Patel | |
Tags: the circulatory system simple nutrients into cells blood circulatory system of human transport in mammals transport in animals human physiology body fluids and circulation biology option d: human physiology transportation in plants and circulation in animals |
The duration of cardiac cycle is
-
0.8 sec
-
0.8 $\mu $ sec
-
0.08 sec
-
0.008 sec
The cardiac cycle consists of a period of relaxation called diastole, during which the heart fills with blood, followed by a period of contraction called systole. The total duration of the cardiac cycle, including systole and diastole, is the reciprocal of the heart rate. For example, if heart rate is 72 beats/min, the duration of the cardiac cycle is 1/72 beats/min about 0.0139 minutes per beat, or 0.833 second per beat.
Each heart beat generates how many pulse in the arteries
-
Two
-
Three
-
One
-
Five
This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The number of heart beats per minute in resting person is called as normal heart rate. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the contractions of the heart cause an increase in blood pressure in arteries that leads to noticeable pulse. Hence each heartbeat generates one pulse in the arteries.
The volume of blood each ventricle pumps out during a cardiac cycle is about
-
70 ml
-
5000 ml
-
71 ml
-
1200 ml
The cardiac output of a normal adult healthy person at rest is almost 5 litres. The volume of blood pumped out of the left ventricle in one beat is called the stroke volume. It is 70 ml.
When we are at rest what will happen to the heart beat?
-
Increase
-
Decrease
-
Remain same
-
Firsts decrease and then increase
The second heart sound (dubb) is associated with the closure of
-
Tricuspid valve
-
Semilunar valves
-
Bicuspid valve
-
Tricuspid and bicuspid valves
'X' is the rhythmic contraction and relaxation in the aorta and its main arteries. What is X?
-
Heart beat
-
Heart rate
-
Pulse
-
Cardiac output
If the systolic pressure is $120$mm Hg and diastolic pressure is $80$mm Hg, the pulse pressure is $80$mm Hg, the pulse pressure is ______.
-
$120\times80 = 9600$mm Hg
-
$120+80 = 200$ mm Hg
-
$120 - 80 = 40$mm Hg
-
$\frac{120}{40} = 3$mm Hg
An adult human with average health has systolic and diastolic pressures as
-
120 mm Hg and 80 mm Hg
-
50 mm Hg and 80 mm Hg
-
80 mm Hg and 80 mm Hg
-
70 m Hg and 120 mm Hg
Blood pressure is the pressure against the walls of the blood vessels produced by the discharge of blood into them by contraction of the left ventricle.
Which one of the following is a matching pair?
-
Lubb - sharp closure of AV valves at the beginning of ventricular systole
-
Dub - sudden opening of semilunar valves at the beginning of ventricular diastole
-
Pulsation of the radial artery - valves in the blood vessels
-
Initiation of the heart beat - Purkinje fibres
The first heart sound is produced when
-
Intraventricular pressure decreases
-
Semilunar valve snaps shut
-
Bicuspid and tricuspid close quickly
-
Diastole begins
first heart sound is produced by the closing of the atrioventricular valves . The first heart sound, or S1, forms the "lub" of "lub-dub" and is composed of components M1 (mitral valve closure) and T1 (tricuspid valve closure). Normally M1 precedes T1 slightly. It is caused by the closure of the atrioventricular valves, i.e. tricuspid and mitral (bicuspid), at the beginning of ventricular contraction, or systole. So, the correct option is C.( Bicuspid and tricuspid close quickly )
In a normal human adult (at resting position), how much blood does the heart pump per minute?
-
5 litre
-
3 litre
-
1 litre
-
7 litre
The blood travels around the body and back to the heart in about one minute if the person is at rest. The heart beats 70 times a minute, with each beat the heart pumps 60 to 90 mililiters (2 to 3 ounces) of blood out of the heart. It can move 5 liters of blood in one minute and 7600 liters (2000 gallons) per day. So, the correct option is "A" (5 Litre).
Which of the following statements is false?
-
$Mg^{2+}$ ions form a complex with ATP
-
$Ca^{2+}$ ions are important in blood clotting
-
$Ca^{2+}$ ions are not important in maintaining the regular beating of the heart
-
$Mg^{2+}$ ions are important in the green parts of plants.
Calcium is important for heart because the movement of calcium ions help the heart muscles to contract. This occurs because: calmodulin, a protein binds to the sodium channel, helps keep it open. Calcium ions regulate the connection between the protein and the channel by causing the protein to hook up to the channel. This in turn, keeps it open and allows sodium ions to pass through. In the absence of Ca$^2$$^+$ the heart beat will be irregular.
The first heart sound is
-
DUP
-
LUBB
-
LUPP
-
BUD
The first heart sound 'lubb' is made by the closing of the mitral valve and tricuspid valve (atrioventricular valves). The second heart sound is 'dub' and is caused by the closure of the aortic valve and the pulmonary valve.
In human beings heart beat is initiated by
-
Purkinje fibres
-
AV node
-
SA node
-
Bundles
Sinoatrial node is a cluster of cells present in the right atria just below the opening of Vena cava. It autonomously generates electrical impulses that initiate the muscle contraction in the atria.
First heart sound is called?
-
Lubb
-
Dub
-
Murmur
-
None of these
- The heart produces a characteristic sound at the beginning g of ventricular systole or contraction.
- These sounds are a result of the closure of the atrioventricular valves, the mitral valve and the tricuspid valve.
- The sounds produced are “lubb-dub”, lubb being the first of the two.
- So, the correct answer is 'Lubb'.
An artifical pacemaker is implanted sub-cutaneously and connected to heart in patients.
-
having high B.P
-
having irregularity in heartbeat
-
having blockage in heart
-
suffering from arteriosclerosis.
A pacemaker insertion is the implantation of a small electronic device that is usually placed in the chest (just below the collarbone) to help regulate slow electrical problems with the heart. A pacemaker may be recommended to ensure that the heartbeat does not slow to a dangerously low rate.
Human heart is myogenic and it is supplied with sympathetic and vagus nerve branches that are acceleratory and inhibitory in nature respectively.Which one of the following statement is incorrect w.r.t the heart beat?
-
In foetal heart the heart rate is $140-130$ beats per minutes
-
Mental status such as depression and grief decrease heart rate
-
An excess of $Ca^{++}$ ion decreases heart beat rate
-
High levels of $Na^+$ and $K^+$ decreases the strength of contraction
Heartbeat rate is the number of the beating of the heart per minute.
- It is found that in normal humans, the rate of heartbeat is about 70 - 72 times per minute but in feotus or babies it is found much higher about 140 - 130 times per minute or may even up to 160 per minute.
- At the time of mental disorders like depression, grief or sadness body releases stress hormone, these stress hormone tightens the blood vessels, thus increases the heart rate.
- Calcium ions play a major role in cardiac activity as well in muscle contraction when they are present in high amount then causes a lower heartbeat.
- Sodium-potassium pumps are the ion channels or proton pumps that regulate the activity of contraction in the heart muscles. Excess of these ions dilates the blood vessels, thus lowers the heart rate and strength of the contraction of the heart muscles.
Time interval between DUP and LUBB is ______ coincide with _____
-
$0.3$ sec, ventricular systole
-
$0.5$ sec, joint diastole and atrial systole
-
$0.4$ sec, joint diastole
-
$0.1$ sec, atrial systole
A moderate increase in the concentration of which of the following ions speeds up the heart rate and strengthens the heart beat?
-
Na$^+$ ions
-
Ca$^{2+}$ ions
-
$K^+$ ions
-
All of these
State whether the following statement is true or false. If false rewrite the correct form of the statement by changing the last word.
The sound produced when the atrioventricular valves close in the heart is called dub.
-
True
-
False
What happen on heart beating if the parasym-pathetic nerve going towards heart is cut down?
-
Increases
-
Decreases
-
Normal
-
Stopped
The volume of blood pumped by heart in one minute is called?
-
Heart rate
-
Systole
-
Cardiac output
-
Diastoles
Cardiac output is the blood volume pumped in a minute by the core. It is equivalent to the rate of heart multiplied by the quantity of the stroke. So if there are 70 beats per minute and with each heart beat 70 ml of blood is drawn, the power production is 4900 ml / minute. This value is typical of an average resting adult, although during intense practice, cardiac production can achieve up to 30 liters / minute.
The first heart sound is semilunar valves
-
Closure of the tricuspid and Biscuspid valves
-
Closure of the tricuspid and biuspid valves
-
Opening of the semilunar valves
-
Opening of the eustachian valve
The first heart sound which we hear is produced by the simultaneous closure of both the atrioventricular valves namely, the bicuspid (mitral) valve and the tricuspid valve.
The volume of blood pumped by heart in one minute is called?
-
Heart rate
-
Systole
-
Cardiac output
-
Diastols
Cardiac output is the blood volume pumped in a minute by the core. It is equivalent to the rate of heart multiplied by the quantity of the stroke. So if there are 70 beats per minute and with each heart beat 70 ml of blood is drawn, the power production is 4900 ml / minute. This value is typical of an average resting adult, although during intense practice, cardiac output can reach upto 30 liters / minute.
The heart rate is increased by
-
An increase in the activity of the sympathetic nerves that supply the heart
-
A decrease in the activity of the parasympathetic (vagus) system
-
An increase in the level of adrenalin in the circulation
-
All of the above
A special neural centre in the medulla oblangata can moderate the cardiac function through autonomic nervous system (ANS). Neural signals through the sympathetic nerves (part of ANS) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output. On the other hand, parasympathetic neural signals (another component of ANS) decrease the rate of heart beat, speed of conduction of action potential and thereby the cardiac output. Adrenal medullary hormones (adrenaline, noradrenaline) can also increase the cardiac output.
Heart rate is accelerated by
-
Cranial nerves and acetylcholine
-
Sympathetic nerves and acetycholine
-
Cranial nerves and adrenalin
-
Sympathetic nerves and epinephrine
Normal activities of the heart are regulated intrinsically, i.e., auto regulated by specialised muscles (nodal tissue), hence, the heart is called myogenic. A special neural centre in the medulla oblangata can moderate the cardiac function through autonomic nervous system (ANS). Neural signals through the sympathetic nerves (part of ANS) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output. On the other hand, parasympathetic neural signals (another component of ANS) decrease the rate of heart beat, speed of conduction of action potential and thereby the cardiac output. Adrenal medullary hormones can also increase the cardiac output. Epinephrine / adrenaline increases the heart rate.
Which one of the following generates heart beat?
-
Purkinje fibres
-
Cardiac branch of vagus nerve
-
SA node
-
AV node
Sino-atrial node (SAN) generates the maximum number of action potentials per minute (70-75/min) and therefore, it sets the pace of the activities of the heart. Hence, it is called as the cardiac pacemaker.
The sound of 'lubb' is produced during closure of
-
Bicuspid valve
-
Tricuspid valve
-
Semilunar valves
-
Both A and B
Typical 'Iubb'-'dupp' sounds of the heart are due to
-
Closing of bicuspid and tricuspid valves
-
Closing of semilunar valves
-
Blood under pressure through aorta
-
Closure of bicuspid-tricuspid valves, followed by semilunar valves
During each cardiac cycle two prominent sounds are produced, which can be easily heard through a stethoscope. The first heart sound (lubb) is associated with the closure of the tricuspid and bicuspid valves, whereas the second heart sound (dubb/dupp) is associated with the closure of the semilunar valves.
Impulse of heart beat originates from
-
SA node
-
AV node
-
Vagus nerve
-
Cardiac nerve
The sino-atrial node (SAN) can generate the maximum number of action potentials, i.e., 70-75 /min. It is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called as the natural cardiac pacemaker.
Identify the correct sequence of events in a cardiac cycle.
-
Diastole, atrial systole, ventricular diastole, ventricular systole.
-
Atrial systole, ventricular systole, atrial diastole, ventricular diastole.
-
ventricular systole, ventricular diastole, diastole, atrial systole.
-
Ventricular diastole,diastole, ventricular systole, atrial systole.
The cardiac cycle starts with atrial systole. It represents the contraction of the myocardium of the left and right atria by which blood is forced into the ventricles. It progresses to ventricular systole, in which the ventricles contract and blood forced into the aorta and pulmonary artery. After that atrial diastole occurs which means the relaxation of atria.The cardiac cycle ends with ventricular diastole in which ventricles are relaxing and also filling with blood in preparation of the next cycle.
The heart of a healthy man beats normally per minute
-
85-90 times
-
80-90 times
-
70-80 times
-
60-70 times
In the human heart, the sino-atrial node (SAN) can generate 70-75 beats/min and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. Our heart normally beats 70-75 times in a minute (average 72 beats/min).
The cardiac impules that results into the heart beat is delayed at
-
Internodal tract
-
AV node
-
Bundle of His
-
Purkinje fibre
The cardiac cycle is regulated by specialized areas in the heart wall, that forms the conduction system of the heart. Two of these areas are tissue mass, called as nodes; the third is a group of fibers, called as the atrio-ventricular bundle.
In cardiac circulation, "dupp" sound is heard, when
-
Mitral valves closes
-
Mitral valves opens
-
Semilunar valves closes
-
Tricuspid valve closes
During each cardiac cycle two prominent sounds are produced, which can be easily heard through a stethoscope. The first heart sound ('lubb') is associated with the closure of the tricuspid and bicuspid valves, whereas the second heart sound ('dubb'/'dupp') is associated with the closure of the semilunar valves.
Pressure exerted by blood against walls of an artery during ventricular expansion is
-
Systolic Pressure
-
Ventricular Pressure
-
Both A and B
-
Cardiac output
The pressure exerted on the arterial wall during left ventricular contraction pushing blood into the aorta. This is called ventricular pressure or ventricular systole. During ventricular systole closing of atrioventricular valves produces the first heart sound lubb. Thus, the correct option is B.
Normal rate of heart beat in a human being is________.
-
32/minute
-
42/minute
-
52/minutes
-
72/minute
The heart is an organ which beats
-
Twenty hours in twenty four hours
-
Ten hours in twenty four hours
-
Continuously
-
Eight hours in twenty four hours
Normal heart rate of a healthy individual is
-
20-40 beats/min
-
60-100 beats/min
-
200-600 beats/min
-
2-10 beats/min
The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat. The frequency of the cardiac cycle or the heart rate is expressed as heart beats per minute. Normal adult human heart rate ranges from 60-100 bpm. So, the correct answer is option B.
Heart beat is initiated by
-
Sinu-auricular node
-
Atria-ventricular node
-
Sodium ion
-
Purkinje's fibres
The sino-atrial node (SAN) is a mass of nodal tissue found in the upper part of right auricle. It generates the nerve impulses which is responsible for starting the contraction of the heart. It controls the rhythm of the heart contraction. Hence, it is called as the natural pacemaker of the heart.
Chordae tending are found in
-
Ventricle of heart
-
Atria of heart
-
Joints
-
Ventricle of brain
Chordae _ tending are numerous, strong inelastic thread like tendons present in the ventricles of the mammalian heart.
Pulse rate can be defined as
-
The rate at which the blood is pumped
-
The rate at which the blood is filtered
-
The rate at which the blood is oxygenated
-
The rate at which the blood is deoxygenated
This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the pumping action of the heart causes an increase in blood pressure in arteries that leads to noticeable pulse. Hence pulse rate can be defined as the rate at which the blood is pumped.
In which animal there is no blood for transport of nutrients?
-
Fish
-
Hydra
-
Sponges
-
Both B and C
All vertebrates possess a muscular chambered heart. Fishes have a 2-chambered heart with an atrium and a ventricle. In fishes, the blood transports nutrients when the heart pumps blood throughout the body. Animals like hydra and sponges do not possess any circulatory system. The water in which they live brings food and nutrients as it enters their body. The water carries waste materials and carbon dioxide as it moves out. Hence In animals like hydra and sponges, there is no blood for transport of nutrients.
The normal heart rate is
-
62 beats per minute
-
72 beats per minute
-
54 beats per minute
-
52 beats per minute
- This sequential event in the heart that is cyclically repeated is called the cardiac cycle.
- Each cardiac cycle consists of systole and diastole of both the atria and ventricles.
- Each cardiac cycle represents one heartbeat. The number of heartbeats per minute in resting person is called a normal heart rate.
- The normal heart rate is about 72 beats per minute.
The amount of blood pumped by the heart per minute is
-
2 litres
-
3 liters
-
5 litres
-
4 litres
- The amount of blood pumped by the heart per minute is called the cardiac output.
- The heart of a normal person beats 72 times per minute. This is called the heart rate. During each and every heartbeat, the ventricles pump about 70 ml of blood.
- This is known as stroke volume. This means heart pumps 72 x 70 ml = 5040 ml or approximately 5 liters of blood per minute.
Thus the correct answer is option C.
The pulse rate can be determined from the
-
Arteries
-
Veins
-
Capillaries
-
Venules
The pulse rate is the number of times one can feel a pulse in one minute. The radial artery is present on the thumb side of the wrist. To measure the pulse rate place two fingers between the bone and the tendon over your radial artery. Count the number of beats in 15 seconds, multiply this with four you will get the pulse rate. Therefore The pulse rate can be determined from the arteries.
The unit of measurement of heart beat is
-
Beats per minute
-
Liters per minute
-
Beats per second
-
Beats per hour
- This sequential event in the heart that is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles.
- Each cardiac cycle represents one heartbeat. The number of heartbeats per minute in resting person is called a normal heart rate.
- The normal heart rate is about 72 beats per minute. Hence the unit of measurement of the heartbeat is Beats per minute.
'Dup' sound is produced during closure of
-
Semilunar valves
-
Bicuspid valve
-
Tricuspid valve
-
Both B and C
- Lubb is the first sound which has a low pitch and produced by the closure of tricuspid and bicuspid valves (collectively called atrioventricular valves) at the beginning of ventricular systole.
- Dup is the second sound which is sharp and has a high pitch. It is produced by closure of semilunar valves by the end of ventricular systole.
The pulse rate can be measured in the
-
Veins of neck
-
Veins of the wrist
-
Pulmonary vein
-
None of the above
This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the pumping action of the heart causes an increase in blood pressure in arteries. Hence pulse rate can be measured in the arteries of the neck and arteries of the wrist.
Heart beat is heard on left side as
-
Aorta is on left side
-
Heart is on left side
-
Ventricles are on left side
-
Left ventricle is on left side.
Sympathetic nervous system
-
Decreases heart beat
-
Increases heart beat
-
Not related to heart beat
-
Controls heart beat.
The hormone that stimulates heart beat is
-
Thyroxine
-
Adrenaline
-
Glucagon
-
Gastrin.
Heart beats originate from
-
Left atrium
-
Right ventricle
-
Cardiac muscles
-
Pace maker.
Which one regulates heart beat?
-
Purkinje fibres
-
Cardiac branch of vagus nerve
-
SA node
-
AV node.
Origin of heart beat and its conduction is represented by
-
AV node $\rightarrow$ Bundle of His $\rightarrow$ SA node $\rightarrow$ Purkinje fibres
-
SA node $\rightarrow$ Purkinje fibres $\rightarrow$ AV node $\rightarrow$ Bundle of His
-
Purkinje fibres $\rightarrow$ AV node $\rightarrow$ SA node $\rightarrow$ Bundle of His
-
SA node $\rightarrow$ AV node $\rightarrow$ Bundle of His $\rightarrow$ Purkinje fibres
- The impulse for heart beat is originated in SA node. It is known as the pace maker of heart and situated in upper right corner of right atrium.
- The electrical impulses generated by SA node are conducted to Atrio Ventricular or AV node.
- From the AV node, the impulses are transmitted to AV bundle, known as bundle of His which convey the impulses of contraction to the apex of myocardium.
- The impulses cause the Purkinje fibres to sweep upwards and outwards which results in pumping of blood into aorta and pulmonary artery.
- So, the correct sequence of propagation of cardiac impulse is SA node, AV node, Bundle of His, Purkinje fibres.
Typical 'lubb-dup' sounds heard in heart beat are due to
-
Closing of bicuspid and tricuspid valves
-
Closing of semilunar valves
-
Blood under pressure through aorta
-
Closure of bicuspid-tricuspid valves followed by semilunar valves
- Lubb is the first sound which has a low pitch and produced by the closure of tricuspid and bicuspid valves (collectively called atrioventricular valves) at the beginning of ventricular systole.
- Dup is the second sound which is sharp and has a high pitch. It is produced by closure of semilunar valves by the end of ventricular systole and beginning of ventricular diastole).
The first heart sound is
-
Lubb during closure of semilunar valves
-
Dupp during closure of semilunar valves
-
Lubb during closure of atrioventricular valves
-
Dupp during closure of atrioventricular valves
- S1: It is the first sound 'lubb'. It has slow pitch and produced by closure of atrioventricular valves at the beginning of ventricular systole.
- S2: It is the second sound 'dup'. It is sharper and has high pitch. It is produced by closure of semilunar valves by the end of ventricular systole.
- S3 and S4 are usually faint and may not be audible. S3 is produced during ventricular filling of heart and S4 is produced during atrial systole.
Pulse is a direct measure of
-
Blood pressure
-
Cardiac output
-
Stroke volume
-
Heart rate.
What will be the number of heart beats per minute, if the stroke volume of heart increases, with total volume of blood remains same
-
Remains constant
-
Decreases
-
Increases
-
Become erratic.
Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound in heard when :
-
AV valves open up
-
Ventricular walls vibrate due to gushing in of blood from artia.
-
Semilunar valves close down after the blood flows into vessels from ventricles.
-
AV node recives signal from SA node.
The rate of heart beat is determined by
-
SA node
-
AV node
-
Purkinie fibre
-
Papillary muscles
In which type of stole, does phloem surround the xylem both externally and internally?
-
Amphiphloic siphonostele
-
Ectophtoic siphonostele
-
Haplostele
-
Actinostle
The rate conduction of impulse in the conducting system of heart is fastest in
-
Atrial muscles
-
Bundle of His
-
Purkinje's fibres
-
AV node
State whether the following statements are true or false.
Human heart is neurogenic because the heart beat originates in the nodal tissues.
-
True
-
False
The heart is entirely made up of cardiac muscles. Muscle cells are also called myocytes. The control of the heart function is by a set of muscles or special node of the modified heart muscle, the sinoatrial node (SAN) located in the atria, so the heart is, therefore, called myogenic.
State whether the following statements are true or false.
The first heart sound results from a closure of semilunar valves.
-
True
-
False
Heart sounds are noises generated by the closing and opening of the heart valves. In a healthy individual, there are two normal heart sounds called lub and dub. Lub is the first heart sound. It is associated with the closure of the tricuspid and bicuspid valves at the beginning of systole. The second heart sound dub is associated with the closure of the semilunar valves at the beginning of diastole.
In heart, automatic rhythmic impulse generation capability is present in the
-
S.A. node
-
A.V. node
-
Bundle of His
-
All of the above
So, the correct answer is 'All of the above'.
Heart sound which is longer is
-
Lubb
-
Dub
-
Both are equal
-
Sometimes (a) and sometimes (b).
The heart sounds normally heard by a physician while holding a stethoscope onto the left side of the chest of the patient are due to
-
Contraction of atrial chambers.
-
Contraction of ventricular chambers.
-
Closure of the atrioventricular valves.
-
Relaxation of the semilunar valves.
In healthy adults, there are two normal heart sounds often described as a lub and a dub, that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves (AV) and semilunar valves respectively.
The heart sound 'dupp' is produced when
-
Tricuspid valve is opened.
-
Mitral valve is opened.
-
Mitral valve is closed.
-
Semi-lunar at the base of aorta get closed.
Heart sounds are heard on the surface of the chest in the heart region; they are amplified by and heard more distinctly through a stethoscope. They are caused by the vibrations generated during the normal cardiac cycle and may be produced by muscular action, valvular actions, motion of the heart, or blood passing through the heart. The second heart sound (S2) is shorter and higher pitched than the first, is heard as a dupp and is produced by closure of the aortic and pulmonary valves.
The rate of heart beat in a rabbit is nearly
-
92 per minute
-
100 per minute
-
150 - 300 per minute
-
None of the above
Cardiac output is estimated by heart beat. The amount of blood pumped by the heart per minute is known as cardiac output. Small mammals have high metabolic rates so they faster heart rates than larger-sized mammals. A rabbit at rest normally has a heart rate that ranges from 140 to 180 beats per minute. Stress can cause the heart rate to increase, and the rate in a stressed rabbit can be quite high: well over 300 beats per minute. Therefore the rate of the heartbeat in a rabbit can be ~ 150-300 per minute.
Systole is comprised of
-
Isovolumetric ventricular contraction
-
Ventricular ejection
-
Both A and B
-
Isovolumetric ventricular relaxation
Systole is the phase of the contraction of the heart while diastole is the phase of the relaxation. During the ventricular systole the following events take place:
The first heart sound is produced when
-
Intraventricular pressure decreases.
-
Semilunar valve snaps shut.
-
Bicuspid and tricuspid valve close quickly.
-
Diastole begins.
The lub is the first heart sound, commonly termed S1, and is caused by turbulence caused by the closure of mitral and tricuspid valves at the start of systole. The second sound, dub or S2, is caused by the closure of aortic and pulmonary valves, marking the end of systole.
One heartbeat in an average man lasts
-
0.8 second
-
0.2 second
-
0.5 second
-
1 minute
One heartbeat in an average man lasts 0.8 second.
The term cardiac refers to which organ in the body?
-
Heart
-
Vein
-
Lymph
-
Capillary
Heart rate is same as
-
Flow rate
-
Pulse rate
-
Breath rate
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Inhalation rate
This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The number of heart beats per minute in resting person is called as normal heart rate. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the contractions of the heart cause an increase in blood pressure in arteries that leads to noticeable pulse.
Seema was running. The supply of oxygen to muscles will __________.
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Remain same
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Increase
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Decrease
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Decrease and then increase
On which side of the human heart is low in oxygen?
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Left ventricle
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Right ventricle
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Left atrium
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Right atrium
Circulation was discovered by
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William Harvey
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Willian Henry
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Michael Harvey
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William Smith
The human circulatory system consists of a muscular four-chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated. Circulation was discovered by William Harvey. He was the first to recognize the full circulation of blood in the human body and to provide experiments and arguments to support this idea.
Mammalian heart is
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Neurogenic
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Myogenic
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Digenic
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None of the above.
The human heart is an example of myogenic heart, it possesses cardiac muscle helping the heart to automatically contract spontaneously; which do not need any stimuli as in neurogenic heart. A myogenic heart is capable of generating a cardiac contraction independent of nervous input. In a myogenic heart, contraction is initiated by the cells called myocyte (Pacemakers)itself instead of an outside occurrence or stimulus such as nerve innervation.
State whether the following statements are true or false.
Smaller animals generally have a lower pulse rate than larger animals.
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True
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False
Smaller animals have much higher metabolism; proportionate to body size, smaller animals tend to have a much smaller heart than larger animals. This means that in order to circulate blood at the same rate, the hearts of smaller animals need to pump more times within a specified time because the volume they can pump each time is smaller.
Choose the correct answer from the alternatives given.
Heart sounds are produced by:
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contraction of the myocardium
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flow of blood in the atria
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flow of blood in the ventricles
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closure of the heart valves
- Heart sounds are noises generated by the closing and opening of the heart valves. In a healthy individual, there are two normal heart sounds called lub and dub.
- Lub is the first heart sound. It is associated with the closure of the tricuspid and bicuspid valves at the beginning of systole.
- The second heart sound dub is associated with the closure of the semilunar valves at the beginning of diastole.
Choose the correct answer from the alternatives given.
The impulses for heart beat originate in:
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A.VN.
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SAN.
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bundles of His
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fibres of Purkinje
The sinoatrial node (SAN) is the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava.
State whether the following statements are true or false.
Rate of heart beat is directly proportional to the size of the body.
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True
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False
The rate of heartbeat is inversely proportional to the size of the body. Smaller animals have a greater heart rate due to increased metabolic rate than the large animals.
State whether the following statements are true or false.
Valves in the cardiovascular system are found only in the heart.
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True
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False
A valve is a membranous structure present in a hollow organ. It folds or closes to prevent the return flow of the body fluid passing through it. The valves present in between the auricles and ventricles are meant to prevent the backflow of blood from the ventricles to auricles. Valves are also a part of veins.
Excessively high heart rate (> 180) can reduce cardiac output because
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Blood is moving too fast through the lungs to pick up enough oxygen
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It tires out the heart muscles and so they pump slower
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It reduces the time for ventricular filling which reduces stroke volume
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The PR-interval increases which leads to longer ventricular diastole and shorter ventricular systole
Heart rate affects both stroke volume and minute volume by altering the length of diastole and thereby the degree of filling and force of contraction. Minute volume and B.P may rise even if the stroke volume falls. This happens with a moderate rise in the heart rate. But if the heart rate is too high, the stroke volume becomes so low that the minute output falls far below the normal.
Bicuspid and tricuspid valves are open during
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Ventricular systole
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Ventricular diastole
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Atrial systole
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Late joint diastole
Atrial systole occurs at the end of ventricular diastole. After the ventricle has pumped its blood, it begins to relax. There is now negative pressure in the ventricle (since it is now empty), and this pressure helps to draw in the blood from the atrium when it enters into systole. So during atrial systole, the bicuspid and tricuspid valves are open, and the pulmonary/aortic semilunar valves are closed. Then during the diastole, the bicuspid and tricuspid valves are closed.