A&P Chapter 1 (ASH)

What is the definition of the heart?

The heart is a pump that moves blood through the vessels of the body.

What is described as flow?

Blood being a fluid that is constantly in motion.

What must be applied to create flow?

Pressure.

What does Boyle’s law state?

Pressure and volume have an inverse relationship; when the volume of a chamber decreases, the pressure inside the chamber increases.

What must happen to the pressure to make flow happen?

The pressure has to be greater than the resistance of blood flow.

Fluids move from areas of ___ pressure to ___ pressure.

High pressure to low pressure (pressure gradient).

What prevents the backflow of blood and ensures one directional blood flow?

Valves.

How does your heart create pressure in your circulatory system?

Contraction (muscle becoming shorter).

What happens to the volume when the muscle contracts to the chambers?

The volume of the chamber decreases.

What happens when the muscle relaxes to the chambers?

The volume of the chamber increases, pressure decreases, and blood flows into the chamber.

What are the two major divisions in the human circulatory system?

Pulmonary circulation & Systemic circulation.

What does pulmonary circulation do?

Sends blood to the lungs to be oxygenated, then returns the oxygenated blood to the heart.

What does systemic circulation do?

Sends oxygenated blood to tissues and deoxygenated blood back to the heart.

The heart has evolved to be a _____?

Double pump.

The right side of the heart pumps blood through which division?

The pulmonary circulation.

The left side of the heart pumps blood for?

The systemic circulation.

What type of blood does the right side of the heart pump?

Deoxygenated blood (oxygen-poor blood).

Where is the heart located in the body?

Within the anterior portion of the thoracic cavity, in between the pleural cavities in a region known as the mediastinum.

The inferior portion of the heart is also known as the?

Apex.

What stabilizes and protects the heart?

Pericardial sac.

What is the outer layer of the pericardial sac called?

Fibrous pericardium.

What is deep to the fibrous pericardium?

Serous pericardium.

What is the serous pericardium?

A serous membrane.

What do serous membranes do?

Protect the heart from impact and friction.

What is the outermost layer of the serous pericardium?

Parietal pericardium.

What surrounds the heart muscle?

Visceral pericardium.

What leads to pericardial effusion?

Abnormal increases in pericardial fluid.

What are the three tissue layers the human heart is composed of?

Epicardium, myocardium, endocardium (EME).

Which layer is synonymous with the epicardium?

Visceral pericardium.

The epicardium is the _____ layer?

Outermost.

The endocardium is the _____ layer?

Innermost/deepest.

Which heart layer is the thickest?

Myocardium.

Why is myocardium the thickest layer?

It has cardiac myocytes (cardiac muscle cells) which help with heart pumping.

What is the endocardium formed from?

Endothelial (simple squamous) tissue.

What is the order from the inside of the ventricular chamber to the thoracic cavity?

Endothelial cell layer, cardiac skeleton, epicardium, pericardial fluid, parietal pericardium, fibrous pericardium.

How many chambers does the heart have?

How many sets of valves does our heart have?

What are the types of valves in the heart?

Atrioventricular (AV) valves & semilunar (SL) valves.

What do the atrioventricular valves do?

They ensure one directional blood flow from the atria to the ventricles.

What do the semilunar (SL) valves do?

Prevent the backflow of blood from the vessels into the ventricle.

What are cusps?

Flaps that are in the atrioventricular valves.

What are the two subcategories of the atrioventricular (AV) valves?

Tricuspid valve & bicuspid (mitral) valve.

What are the two subcategories of the semilunar (SL) valves?

Aortic valve & pulmonary valve.

What does the chordae tendineae do?

Eversion.

Blood is pumped out of the heart by the?

Ventricles.

Blood comes into the heart through the?

Atria.

What type of blood does the left side of the heart handle?

Oxygenated blood.

What type of blood does the right side of the heart handle?

Deoxygenated blood.

What large vein carries deoxygenated blood into the right atrium?

Superior vena cava.

What does the inferior vena cava carry blood from?

The lower portion of the body into the right atrium.

Where are the superior and inferior vena cava located?

On the posterior side of the right atrium.

What is the order of structures a red blood cell encounters after leaving the left ventricle?

Aorta, systemic capillary, vena cava, right atrium, right ventricle, pulmonary artery, pulmonary vein, left atrium.

What is the foramen ovale?

A tiny hole in the heart that separates the right and left atria during fetal development.

What is the ductus arteriosus?

A shortcut that connects the pulmonary trunk to the aorta during fetal development.

What are the foramen ovale and ductus arteriosus known as?

Fetal shunts.

Occlusion is a characteristic of?

Coronary artery disease.

What are the tiny connecting vessels making up collateral circulation?

Anastomoses.

What do cardiac myocytes have?

A single nucleus.

Why doesn’t recruitment of fibers happen in cardiac muscles?

Due to intercalated discs.

Cardiac muscle lacks innervation by?

Motor neurons.

Why does cardiac muscle lack innervation by motor neurons?

Because it is autorhythmic (able of self excitation).

What are the two major cell populations within the myocardial layer of the heart?

Pacemaker cells & contractile myocytes.

What are pacemaker cells?

Autorhythmic and less than 1% of heart cells.

What do contractile myocytes do?

Generate force and make up 99% of heart cells.

What must happen before contraction & relaxation?

An electrical signal.

What do arteries always do?

Carry blood away from the heart.

What do veins always do?

Carry blood towards the heart.

What does occlusion mean?

Blockage.