18. Heart and Circulatory System Flashcards
How much does the human heart weigh?
250-450g
How many times does the heart beat a day?
~100 000/day
How much blood does it pump? (/beat and/day)
~70mL/beat, ~7200L/day
How many times does it circulate blood in a day?
1300 times a day?
How many times does the heart beat + how much blood is pumped? (<1 second, 1 min, 1 day, 1 year, 70 years)
<1 second - 1 beat, 70ml
1 minute - ~70 beats, 5L
1 day - 100 000 beats, 7200L
1 year - 38 million beats, 2.6 million L
70 years - 2.5 billion, 184 million L
What are the two muscles that support the double pump?
Atrial musculature, Ventricular musculature
Are the atrial muscles and ventricular muscles thin.
Atrial muscle: thin
Ventricular muscle: thick and strong
How are tendons arranged and why are they arranged like that?
Bundles of collagenous fibers arranged in parallel.
They are arranged this way to form cords which have great tensile strength.
What is the function of tendons?
To anchor or bind muscles to bones.
What does the septa do?
Prevents mixing of blood flow
Why do cardiac muscles never get tired?
- Steady supply of O2 and nutrients through coronary artery.
- Cardiac muscles have more mitochondria than skeletal muscles to supply enough ATP.
What does the Sinoatrial Node do?
The SA node is the most imp. element in the electrical circuit of the heart.
Starts the cardiac cycle by periodically generating action potentials without any external stimulation.
“Pacemaker of the heart”
What nerves control the heart beat rate?
Sympathetic nerve + Parasympathetic (vagus) nerves
How is a normal heart beat maintained?
Slow continuous discharge from sympathetic nerves.
What composes the protection system of the heart?
Adipose tissue
Pericardium
Pericardial fluid
Epicardium
What does the pericardial cavity contain and why?
Small amount of serous fluid –> reduce surface tension and lubricate –> cavity facilitates the free movement of the heart
What is the total area of blood vessels?
~1000m^2
What is the structure of arteries?
Thick and elastic layers
Smooth muscle layer for dilation and construction
What is the structure of veins?
Thinner than arteries
Have safety valves
Elastic material
What is the structure of capillaries?
Very thin
Endothelial cells
Size: 0.5 micro m
How can blood be transported in one way? (upward)
Venous valves: one way valve in vein
Contraction of skeletal muscle
What is Angiogenesis?
Formation of new blood vessels from the existing vasculature.
Migration, growth, differentiation of endothelial cells (lined in the inside wall of blood vessels)
How many Americans suffer from heart failure?
5.7 million
How many annual cases of heart failure are there in the US?
670 000 new cases of heart failure annually
How many Americans die due to heart failure each year?
300 000 people
Where is the artificial heart placed?
Replacing the right/left ventricles
How much does the SynCardia Heart weigh?
160g
SynCardia Heart implanted ever since?
2010
What is the relationship of exercise and heart?
More exercise –> bigger heart –> bigger pump –> more blood out –> more oxygen to muscles –> more energy
