Unit 1: Structue & Function Of The Heart Flashcards
Definition of Heart rate (pulse) (HR)
No. Of heartbeats that occurs per minute
Definition of stroke volume (SV)
Volume of blood expelled by each ventricle on contraction. The stronger the connection, the greater the stroke volume.
Definition is cariac output ( CO)
Volume of blood pumped through the ventricle per minute
What is the equation to work out cardiac output (CO)
CO= HR x SV
Definition of systole
The chambers of the heart contract
Definition of diastole
The chambers of the heart relax
Divination of cardiac cycle
One complete sequence of filling & pumping blood
What happens during atrial systole
Atrial systole transfers the remainder of the blood through the atrioventricular valves to the ventricles
What happens during ventricular systole
Ventricular systole closes the AV valves and pumps the blood out through the semi lunar valves to the aorta and pulmonary artery
Where does the heat beat originate
In the heart itself
What is responsible for the heart sounds heard through a stethoscope
The opening and closing of he AV valves and SL valves
What does SAN stand for
Sinoatrial node
What sets the rate of cardiac conduction
SAN
How does the SAN control the rate of cardiac conduction
Auto-rhythmic cells
Where does the SAN set the rate of cardiac contraction
(Auto-rhythmic cells) -(located in) The wall of the right atrium
Where is the AVN located
Base of artia
What does AVN stand for
Atrioventricular node
What does the AVN do
Sends impluses down conducting fibers between ventricles and up across ventricles causing ventricular systole
The flow chart for cardiac conduction- contraction of the heart
SAN sets the rate of cardiac contraction (wall of RA) ⬇️
Blood flows into RA & falls into RV
⬇️
Electrical impulse from SAN across artia into AVN causes artical systole ⬇️
Blood is forced into RV
⬇️
As pressure in the RV builds, AV valve closes
⬇️
Impulse travels down middle of the heart & up the ventricle walls causing ventricular systole
⬇️
Blood is forced out into blood vessels through SL valves ⬇️
As pressure builds in blood vessels , SL valves close
What do electrocardiogram dectect
The electrical impulses in the heart
What is used to detect electrical impluses in the heart
Electrocardiogram
What regulates the SAN
Medulla - through antagonistic action of the autonomic nervous system
What do sympathetic nerves release
They release nor-adrenaline to increase heart rate (HR)
What do parasympathetic nerves release
They release acetylcholine to decrease heart rate (HR)
What are the P waves in an ECG
Electrical activity during atrial systole
What are the ORS waves in an ECG
Electrical activity during ventrical systole
What are the T waves in an ECG
Ventricular repolarsation (recovery of ventrical walls)
What does ECG stand for
Electrocardiogram
What is blood pressure
Friction between blood and blood vessels
Does blood pressure increase or decrease during ventricular systole
Increases
Does blood pressure increase or decrease during ventricular systole
Decreased
What do you measure blood pressure with
Sphygmomanometer
Fill in the blank:
The more space in the blood vessel the ———— the blood presssure
Lower
How does a sphygmomanometer work
It is a cuff inflated to stop blood flow through artery and deflates gradually
When measuring blood pressure - When is the first pressure reading
Taken when cuff begins to deflate and blood starts to flow (systolic pressure)
When measuring blood pressure - when is the 2nd reading taken
When pressure falls to where no sound is heard in the artery and blood flows freely(diastolic pressure)
What is systolic pressure
Blood flow starts (detected as a pulse)
What is diastolic pressure
Blood flows freely (no pulse detected)
What is a typical reading in a sphygmomanometer
120/80 mmHg
What is hypertension
Chronic(prolonged) high blood pressure
What is hypertension a major risk for
For many diseases including coronary heart disease (CVD)
