Physiology and Health Unit 2 KA 6 Flashcards
Structure and Function of the heart
What is the Heart made up of?
The heart is made up of cardiac muscle
What are the four chambers of the Heart?
1) Right Atrium
2) Right Ventricle
3) Left Atrium
4) Left Ventricle
Where does the Right ventricle pump blood?
The right ventricle pumps blood to the lungs
Where does the Left ventricle pump blood?
The left ventricle pumps blood to the whole body
Which Ventricle has a thicker muscle?
The left ventricle has a thicker muscle because it pumps blood around the whole body
What do the AV valves do?
(Atrio-ventricular)
The AV valves prevent the backflow of blood from the ventricles into the atria
What do the SL valves do?
(Semi-lunar)
The SL valves prevent the backflow of blood at the entrance of the arteries leaving the heart back down into the ventricles
When do the SL valves open?
The SL valves open during ventricular systole (contraction), allowing blood into the arteries
When do the SL valves close?
The SL valves close when the muscle relaxes (diastole)
What is Heart rate?
Heart rate is the number of heartbeats that occurs per minute
What is Stroke volume?
Stroke volume is the volume of blood expelled by ventricles on contraction
(Stronger the contraction, greater the stroke volume)
What is Cardiac Output?
Cardiac output is the volume of blood pumped out of a ventricle per minute
What is the equation to find CO?
(Cardiac output)
CO = Heart rate x stroke volume
Diastole is ____
Systole is ____
(Fill in the blanks)
Diastole is relaxation
Systole is contraction
What is stage 1/3 of the Cardiac cycle?
Stage 1 of Cardiac cycle -
Atrial and Ventricular diastole
(both chambers relaxed, filling with blood)
(AV valves open/SL valves closed)
What is stage 2/3 of the Cardiac cycle?
Stage 2 of Cardiac cycle -
Atrial systole
(atria contract, remaining blood pushed into ventricles)
(AV valves open/SL valves closed)
What is stage 3/3 of the Cardiac cycle?
Stage 3 of Cardiac cycle -
Ventricular systole
(ventricles contract and push blood out through arteries)
(AV valves closed/SL valves open)
What is responsible for the heart sounds heard with a stethoscope?
The opening and closing of the AV and SL valves is responsible for the heart sounds heard with a stethoscope
Where is the SAN (pacemaker) located in the heart?
(sino-atrial node)
The SAN (pacemaker) is located in the wall of the right atrium
What does the SAN do?
The SAN sets the rate at which the cardiac muscle cells contract
How does the SAN cause atrial systole?
The SAN causes Atrial systole by spreading impulses through the atria
Wherabouts is the AVN located?
(Atrioventricular node)
The AVN is located in the centre of the heart
Where do impulses travel after spreading from the SAN to the AVN?
Impulses travel from the SAN to the AVN and down the central wall of the heart, then up through the walls of the ventricles causing Ventricular systole
How can impulses from the SAN be detected?
Impulses by the SAN can be detected by an electrocardiogram (ECG)
Where is the control centre in the brain which regulates the rate of the SAN?
The Medulla in the brain regulates the rate of the SAN
How does the Medulla regulate the rate of the SAN?
The medulla regulates the rate of the SAN through the antagonistic action of the ANS
