Heart

Question 1

How does the heart work?

Answer 1

The heart has 2 atria (left and right) that supply the 2
underlying ventricles (left and right) with blood.
* The blood always flows from high pressure to low
pressure areas.
* The right ventricle of the heart receives blood from
the deoxygenated venous circulation via the right
atrium.
* The right ventricle then pumps the blood into the
pulmonary (small) circulation where it gets
oxygenated.
* The oxygenated blood then comes back to the left
atrium of the heart down to the left ventricle which
pumps it out to the aorta and into the arterial
circulation.

Question 2

What is the 4 heart valves called and where are they located?

Answer 2

Tricuspid valve - Right Atria
Pulmonary valve - Right ventricle
Mitral valve - Left Atria
Aortic valve - Left ventricle

Question 3

The cardiac cycle - What is the two different systems called?

Answer 3

Diastole and systole

Question 4

What is diastole?

Answer 4

During the diastole blood flows from higher pressure to lower through the atrium down
into the ventricles.
– In the end the atria contract, pressing a last small volume of blood into the ventricles

Question 5

What is systole?

Answer 5

When systole starts the ventricles start contracting, closing the A-V valves. When the
ventricles have built up enough pressure the aortic and pulmonary valves open and
blood flows out into the aorta and pulmonary system.

Question 6

The heart has its own natural pacemaker, how does it work and what is the most important things called?

Answer 6

The heart can keep pumping without
any signals from the rest of the body.
* It has its own pacemaker built in and
in a normal heart the signal starts in
the Sinoatrial-Node located in the
right atrium.
* First the action potential (electrical
signal) spreads to both atria, and is
delayed in the atrioventricular node
(AV) before being transferred to the
ventricles.

Question 7

Normal restering heart rate (Sinus rhythm), is how much?

Answer 7

60-100 beats pr. minute.

Question 8

Heart rate ( Baroreceptor in carotid sinus and aortic arch) can be influenced by some different things, name them?

Answer 8

Hormonal influence from adrenalin
– Neural influence comes from the innervation from the:
* Parasympathetic nervous system (brake)
– Vagus Nerve (10th Cranial nerve)
* Sympathetic nervous system (accelerate)
– From spinal cord Th1-4

Question 9

What is the main task of a ElectrioCardioGram?

Answer 9

Registration of the electrical conduction in the heart
* The heart is being «looked at» from different angels
* Used to detect rate, arrhythmias, hypoxia in heart muscles

Question 10

What is the Stroke volume?

Answer 10

Amount of Blood the heart
pumps out in one heartbeat (can vary from
beat to beat)

Question 11

What is the heart rate?

Answer 11

How many times the heart
muscle contracts in one minute

Question 12

What is the cardiac output?
And how do you figure it out?

Answer 12

The volume of blood
pumped from the heart in one minute
* Example:
– Person with HR of 72 and SV of 70 ml
– 72 bpm x 70 ml = CO 5040 ml /min

Question 13

There are some factors affecting the heart rate, name them?

Answer 13

Fitness levels
Age
Hormones:
– Example:
* Epinephrine/Adrenaline involved in ↑ HR

Question 14

Factors affecting stroke volume?

Answer 14

Heart size
Fitness levels
Gender
Contractility
Duration of contraction
End-Diastolic Volume or Preload (EDV)
* Amount of blood in the ventricles just before contraction
– End-Systolic Volume (ESV)
* Amount of blood in the ventricles after contraction Vascular Resistance:
– Afterload: Resistance the heart must pump against to eject
blood
* Vasodilation causes “Afterload” ↓
* Vasoconstriction causes “Afterload” ↑