1.1 the heart Flashcards
4 key functions of the circulatory system
1) transports and delivers O2 and nutrients to the cells in exchange for CO2 and waste materialsnutrients: minerals, vitamins, glucose
2) transports and delivers chemical messengers throughout the bodychemical messenger: hormones
3) regulates body temperature
4) defends against disease
3 major components of the circulatory or cardiovascular system
heartblood vesselsblood
in which direction is blood pumped? - from veins to arteries or- from arteries to veins
from arteries to veins
does the veins keep the blood moving in one direction?
yes
what connects arteries to veins
capillaries
are heart, arteries and veins all connected?
yes
cardiac output definition
volume of blood pumped by the heart PER minute
the greater the value of cardiac output (4)
- the better the heart as a pump
- the stronger the heart is as a muscle
- the more fit the person is
- the bigger the value of stroke volume
how to determine cardiac output
(stroke volume x heart rate)
stroke volume definition (2)
- volume of blood pumped by heart PER beat
- The quantity of blood pumped from the hearts left ventricle during each contraction PER beat
average stroke volume of adult …- male - female
- male is 70 mL / beat
- female is 60 mL / beat
the greater the value of stroke volume…(4)
- the lower the value of RHR
- the better the heart as a pump
- the stronger the heart is as a muscle
- the more fit the person is
RHR definition (1)
of contraction of the heart that occur PER minute while the body is at a complete rest
Heart rate definition
- how many times the heart beats PER minute
Why does the heart rate vary?
The heart rate can vary according to the body’s physical needs, including the need to absorb oxygen and excrete carbon dioxide
What determines how effective the heart is as a pump
- stroke volume (big value)
- cardiac output (big value)
- resting heart rate (small value
what happens when the heart contracts?
when it contracts, it pumps blood
what is the 1st organ that the heart supplies with O2 rich blood?
itself
Coronary Artery definition
the blood vessels that supply that heart muscles with oxygenated blood.
where is the coronary artery?
on the surface of the heart
What regulate the rate of heart beat?
will either accelerate or decelerate the heart beat
pacemaker or SA node
pacemaker or SA node definition
generates electrical signals that cause the muscle fibres in the heart to simultaneously contract in a co-ordinated manner
what happens If one muscle fibre of a heart chamber is stimulated to contract?
all the fibres of that chamber contract in unison (all together)
How to know that there is something wrong with the pacemaker?
heart’s pacemaker cells are unable to regulate a steady and fixed heartbeat = irregular heartbeat
how many chamber does the heart have?
4 chambers
where is the heart located? and what protects it?
- almost at the centre on the chest
- protected by the Sternum or Breastbone
why is the stethoscope is used on the left side of the heart?
because sounds from the heart are easier to hear here
The RED is …
- on (L) or (R) ?
- oxygenated or deoxygenated?
- (L)
- oxygenated
The LEFT is …
- on (L) or (R) ?
- oxygenated or de-oxygenated?
- (R)
- de-oxygenated
septum
a thick wall of muscle that divides the left and right sides of the heart.
Atrium
the smaller upper chamber that receives blood returning to the heart
the (L) and (R) atrium together is called
atria
ventricle
the larger v-shaped bottom chamber that pumps blood from or out of the heart
Why is the (L) ventricle is slightly bigger in size?
because its job is to pump O2 rich to most of the body
Heart valves
he thin flaps of tissue in the heart that open and close to ensure the proper direction for blood flow
what divides the 4 chambers?
heart valves
what ensures that the blood will only travel in one direction within the heart?
heart valves
how are the valves between atria and the ventricles held in places?
- string-like tendon
what does the string like tendons do?
help ensure that the valves are closed correctly.
Blood flow through the heart
- From the body - (R side) -
(4)
- blood enters the heart and collects in the right atrium from both the superior and inferior vena cavae
- the contraction of the right atrium forces blood into the right ventricle
- the right ventricle contracts and forces the blood to flow into the pulmonary arteries
- at the lungs, the blood undergoes gas exchange by receiving O2 and releasing CO2.
venae cavae
large veins that collect O2 poor and CO2 rich blood from the upper and lower body
superior vena cavae
O2 poor blood coming from the upper body
Interior venae cavae
O2 poor blood coming from the lower body
Pulmonary arteries:
move the O2 poor blood away from the heart toward the right and left lungs.
Blood flow through the heart
- From the lungs - (L side) -
- O2 rich blood from the (L) and (R) lungs is then sent back to the heart through the pulmonary veins to the left atrium
- the contraction of the left atrium forces the blood into the left ventricle
- the contraction of the left ventricle forces the blood into the aorta.
which chamber is the most muscular in the heart?
Left ventricle
Aorta
the largest artery in the body and through its many branches, directs O2 rich blood to the entire body
tell the heart anatomy from a picture
adsf
does the Blood move through one chamber while the other chambers lay empty waiting for their turn to move the blood
on?
no
- instead, the two sides of the heart fill at the same time and act together like parallel pumps
once the heart it filled with blood…
atria..
ventricle
- both atria contract at the same time
- followed by the simultaneous contraction of both ventricles
what are the ventricles do before they contract?
What is the relaxation part of the heart beat cycle?
- they are relaxed and the valves between the atria and the ventricles are open. This allows blood to flow in and fill in the ventricle chambers.
- Diastole
Ventricle relaxed causes…
- the valves between the atria and the ventricles are open. This allows blood to flow in and fill in the ventricle chambers
Diastole
the phase of the heart’s cycle where a chamber of the heart, either an atrium or a ventricle, relaxes and fills with blood
Two-step contraction
- these 2 part contraction of the heart cycle is called
- the first step, atria contract together to push the blood down into the ventricles
- in second step, both ventricles contract to force the blood out of the heart
- Systole
heart beat in a summary
One complete contraction (systole) and one complete relaxation (diastole) “combine” to make a heartbeat
The “lub-dub” heart sound that a doctor listens for through a stethoscope is due to …
the heart valves functioning during diastole and systole.
what valve closes that makes the sound “lub”?
- is “lub” made during systole and diastole
- AV valves closed
- systole
what valve closes that makes the sound “dub”?
- is “dub” made during systole and diastole
- semilunar valves
- diastole
Heart murmur are usually due to..
- abnormal functioning of a heart valve
- a valve may…
- not be closing tightly
- too narrow or too stiff
heart murmur results “from”…
the turbulent flow of blood throughout the heart
are heart murmurs fatal ?
NO, most are not associated with heart disease or abnormalities. Most innocent murmurs the children have will usually disappear by the time they become adults
what is the pump that drives the circulatory system?
the heart
what does the output of blood depends on?
how many times the heart contracts and how much blood it moves with each contraction
“lub-dub” detailed explination
The atria contract simultaneously, followed by the simultaneous contraction of the two ventricles. This two-part contraction creates a “lub-dub” sound due to the functioning of the heart’s valves
heart rate is affected by…
- emotion
- temperature,
- exercise fitness level, - sleep
- hormones,
- chemicals
- drugs
- alcohol
what is the key indicator cardiovascular fitness?
Heart rate is a key indicator of cardiovascular fitness
