A muscular and fibrous septum separates injuries from each other.
The arteries that distribute the blood have platelets sticking to them.
A plug is formed by platelet plug to each other.
The scanning electron micrograph has a left example of a clot.
Animals can lose too much blood if they are injured.
As the injured vessel heals, the body absorbs the clot.
In this section, we will look at the illustration of a human heart which shows the major blood vessels and function of the heart, focusing on the human heart, entering and leaving the heart, and the relationships of the four which carry out a double circulation.
The red and blue regions contain oxygenated blood.
The direction that blood flows through the heart is controlled by valves.
The blood is between the atria and ventricles.
Blood flows down a pres different, the increase in Ca2+ causes contraction through the atria into the ventricles.
The nervous system can regulate the deoxygenated blood pumped into the lungs by the right ventricle.
The left semilunar valve is used to pump oxygen to the rest of the body.
The beating of the heart can be initiated by nerves or by the heart muscle cells themselves.
If the nervous heart does not send regular electrical impulses to the muscle, it will not be able to contract.
The myogenic heart of all animals has two phases, one of which is the signaling mechanism that causes contraction.
The electrical signals are generated by the cardiac muscle.
There is a collection of modified myocytes that are connected between individual cardiac muscle cells.
Each myocyte has a set of extensions that form in the middle of the cell and allow it to lock with other myocytes.
The influx of positively charged ion into the cell is called the influx of positively charged ion into the cell.
The atria to the atrioventricular is where the electrical activity begins and ends.
The branches transmit electrical activity to the ventricles.
The atria and ventricles don't contract until they are excited.
The forces that open or close the two sets of heart valves are changes in pressure between the atria and ventricles.
The left semilunar valve is only partially visible in this orientation.
A given species has a range of frequencies that are characteristic.
An animal's heart rate is determined by the Frequency.
The potentials spread across both atria through the gap junctions once the SA cells generate action potentials.
The action potentials cause an influx of Ca2+ through gated aorta channels.
The atria contract as if they were one large muscle cell because of the rapid spread of impulses.
A final push of blood is provided by atrial contraction.
The atria and ventricles do not have gap junctions, so action potentials must somehow move to the ventricles.
The cells of the SA node need a longer time to become excited than the cells of the AV.
This delay allows time for the atria to contract.
A system of cardiac muscle cells that extends throughout the muscular walls of the ventricles is spread by fibers branching from the AV node.
The semilunar valves of a human heart are shown in this illustration.
Pres are generated through the open AV valves as the ventricles pump out blood.
At the end of diastole, the atria are electri sure, but eventually y the pressure must be lowered so that they can fil cally stimulated, which provides a boost of blood again.
The blood can be ejected through the open semilunar valves.
The higher pressure in the arteries causes backflow of blood towards the atria and ventricles, which causes the semilunar valves to close.
During diastole the heart's ventricles are actually flowing back into it.
The semilunar valves relax, the pressure in the ventricles is lower than in the atria, and the second heart sound is heard through a stethoscope.
The atria are closed, but the semilunar valves are open.
When the ventricles are excited, con blood from the veins begins to flow, which increases the pressure in the atria tract.
The beginning of systole is marked by the pressure in the atria.
The thicker the ventricles, the greater the volume of blood flowing into them.
During dias atria, when the ventricles are generating pressure, the lowest pressure is experienced.
The sound of the familiar tole is made when the ventricles are relaxing.
Blood pressure is heard through a stethoscope.
Ventricular pressure is measured with two numbers.
The ventricles are contracting.
The units are usually given in millimeters of mercury in the ventricles because of the historical reasons.