The heart Flashcards
Contrast single and double circulation.
Single Circulation:
- flows through the heart 1x per cycle
- heart has only one atrium and ventricle
- when blood becomes deoxygenated, it is pumped to gills which oxygenate the blood
Double circulation
- blood flows through the heart twice per complete cycle
- The right side of the heart received deoxygenated blood back from the body and sends it to the right atrium-> right ventricle. It is now pumped into the lungs for oxygenation
- the left ventricle received this oxygenated blood, pumps it into the left atrium and into the body
What are the differences/ similarities between skeletal and cardiac muscles
Simlarities:
- striated appearance
- similar arrangement of actin and myosin
Differences:
Skeletal:
-longer
-narrower
multinucleate
-voluntary control
Cardiac:
- shorter
- wider
- one nucleus
- non-voluntary control
Describe cardiac muscle cells
- branched
- connected via intercalated discs
- low electrical resistance(free diffusion of ions)
- one nucleus
- discs run perpendicular to directoin of muscle cells
What does the connections of intercalated discs provide to the heart?
- in sync contractions of cells
- rapid transmission of electrical impulses
The 3 veins of the heart
Aorta, pulmonary artey, coronary arteries
Describe the pulmonary artery
2 branches carrying deoxygenated blood to the lungs
Describe the aorta
Carries oxygenated blood from the left ventricle into the body
Describe the superior vena cava
carried deoxygenated blood from the body into the right atrium
Describe the inferior vena cava
Carries deoxygenated blood from the body into the right atrium
Describe the pulmonary vein
Carries oxygenated blood from the lungs into the left atrium and into the body
Describe the coronary artery
It is connected to the aorta and carries the most oxygenated blood to the heart muscle
What carries the freshest blood to the heart muscle?
The coronary artery
Describe the right artrioventricular valve (trisculpid)
- parachute like
- prevents backflow from the right venrticle into the atrium
- has 3 cusps( attached to tendious cords)(3 parts and large)
Describe the left artrioventricular valve (mitral)
- looks like a line trawn through the valve
- is two parts
- prevents backflow from the rigth ventricle to the atrium
Describe the pulmonary semilunar valve.
- prevents back flow from the pulmonary artery to the right ventricle
- 3 parts, smaller than tricuspid
- 3 half-moon cusps
describe the aorrtic semilunar valve
- prevents back flow form the aorta into the left ventricle
- 3 half moon cusps
What is the cardiac cycle
Events which happen in the heart from the end of a heart beat until the end of a next one
Right before a new cardiac cycle begins, what happens?
blood is rushing in from the body and the lungs
How is the SA node started?
By blood rushing in from the body and the heart
What is systole?
Contraction
What is diastole?
Relaxation of the heart
Describe the steps in the cardiac cycle
Blood passively flows into the right and left atriums.
SA node is stimulated and releases electrical stimuli passing from cell to cell.
The atriums contract, pushing the blood out into the ventricles. The specialised bundles of fibres carry signals to the AV node.
When the ventricles fill, the AV node signals the AV bundle.
The AV bundle carries impulses to septum and from there to the purkinje fibres, signaling the walls of the L and R atriums to contract.
What is the first noise of a heart beat?
“LUB”
The mitral and tricuspid valves shutting.
What is the second loud noise of a heart beat?
“DUB”
The pulmonary and aortic valves shutting
WHat is a healthy sound of a heart?
Lub-Dub
What is an unhealthy sound of a heart?
Murmur
List the nodes step by step
SA node
AV node
AV bundle
Septum
Purkinje fibers
What is the last step in the cardiac cycle?
The purkinje fibers signal the walls of the ventricle to contract
EKG traces graph the cardiac cycle.
P
QRS
T
(like the alphabet)
are different steps in the cycle. What are they?
P is the SA node firing and atria contracting
QRS is the AV node iring and ventricles contracting
T is the relaxing(diastole) of the ventricles
What is used to listen to the heartbeat?
A stethoscope
How did Rene laennec get the idea of the stethoscope?
He saw children transmit sound through wood. He tried this with tightly rolled paper and it worked, he decided upon a hollow wooden tube.
What does myogenic mean?
Controlled by muscle
WHat is the control of the heart beat?
Myogenic
What are two technologies which deal with a failing heart?
Defilibrators and artificial pacemakers.
Explain artificial pacemakers
They maintain the naturing rythm of a heart beak
- they monitor the heart
- send impulses only when the heart misses a beat
explain defilibrators
- they treat life threatening cardiac conditions
- during a heart attach the heart is deprived of O2 and contracts chaotically.
The defilibrator sends electrical impulses across the heart to restore the natural rythm.
What controls the speed of a heart beat?
The nervous system
Where is the cardiac center in the brain?
Medula oblongata
What two nerves in the medula oblongata control the heart rate difefrently.
- vaus nerve
- sympathetic nerve
What does the vagus nerve do
It decreases the heart rate(eg. during cool down)
What does the sympathetic nerve do?
- increases heart rate(eg. during exercise)
What does the endocrine system control?
- stimulates pacemaker
- adrenaline
-accelerates heart
What is imbalance in nutrition?
not enough vitamins and mineral intake. This results in abnormal heart contractions
What is excess in nutrition?
- having too much nutrition
- overweight
- related to coronary heart disease
- high blood pressure
What is deficiency in nutrition?
- under nutrition
- loose weight
The body will eat itself
- glycogen for energy
- muscle for protein
- triglycerides for fats
If heart muscle is beaing eaten, the heart becomes weak and so does blood pressure.
- increased risk of heart failure
Why is double circulation so important?
it allows the pulmonary and systemic vessels to push blood with different pressures. The aorta withstands great amounts of pressure while the pulmonary artery must be careful as the lung could be damaged from high pressures.
Compare the lumen diameter and wall layers of veins, arteries and capillaries.
Arteries:
THICK
- Tunica adventita
-Tunica media
-Tunica intima
Veins:
thinner
-tunica adventita
-tunica media
-tunica intima
Capillaries
extremely thin- one cell thick
- tunica intima
Compare the pressures of veins, arteries and capillaries
Veins:
low
- need to pump into lungs and body
Arteries
- coming in passively
high
capilarries:
low
Compare the lumen diameter of veins, capillaries and arteries
arteries: narrow
veins: wide
capillaries: tiny: one cell wide
Compare the function of arteries, veins and capillaries
arteries: carrying blood out of the heart
veins: carrying blood into the heart
capillaries: material exchange with tissues
