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Flashcards in Cardiovascular System Deck (131)
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What is the Mediastinum?

The mediastinum is the central compartment of the thoracic cavity, situated between the lungs.


What does the mediastinum contain and consist of?

It contains all the thoracic structures except the lungs and is a highly mobile region in the living because it consists primarily of hollow visceral structures which are joined by loose connective tissue.


Describe where the inferior mediastinum is situated.

The mediastinum extends from the superior thoracic aperture to the diaphragm and from the sternum and costal cartilages to the bodies of the thoracic vertebrae.


Name the 3 parts of the inferior mediastinum.

- Anterior mediastinum
- Middle mediastinum
- Posterior mediastinum


Describe where the superior mediastinum is situated.

Extends inferiorly from the superior thoracic aperture to the horizontal plane, which includes the sternal angle and passes approximately through the junction of T4 and T5 vertebrae posteriorly.


What does the superior mediastinum contain?

Contains the roots of the great vessels and the trachea.


Define the sternal angle.

The sternal angle is the joint between the manubrium (top part) and the body (middle part) of the sternum. It also marks the division of the superior and inferior mediastinum.


At what vertebral level is the sternal angle found?

Between T4 and T5.


Which part of the inferior mediastinum contains the heart?

The middle mediastinum.


What lies within the fibrous pericardial sac?

The heart.


The pericardial sack is fused superiorly with what?

The aorta and pulmonary trunk.


The pericardial sac is blended inferiorly with what?

The central tendon of the diaphragm.


The pericardial sac has a tough fibrous outer layer (the fibrous pericardium) which protects the heart against sudden over filling by doing what?

Physically preventing overexpansion.


What is the internal surface of the fibrous pericardium lined with and what does it do?

A serous membrane which passes onto the surface of the heart to provide a continuous membrane surrounding the fluid filled pericardial cavity.


What is the epicardium?

The visceral layer of the serous pericardium.


What does the fluid in the pericardial cavity do?

The fluid in the pericardial cavity allows the heart to beat in an almost frictionless environment.


Name the 2 circulatory systems.

Pulmonary and systemic systems.


Name the 4 chambers of the heart and their relative positions.

Left & Right Atria. Left and Right ventricles. The atria are the upper chambers.


What are the chambers of the heart made of?

Specialised cardiac muscle known as myocardium.


True or false? Expulsion of blood from the hearts chambers is a passive process.

False. Contraction of the cardiac muscle pushes blood out of the chambers. The passive process of relaxation causes the chambers to refill.


Define Systole.

Contraction of the ventricles.


Define Diastole.

Relaxation of the ventricles.


Pulmonary, derived from the Latin for lungs, is used to describe what?

Objects or systems that are related to the lungs.


Is the pulmonary circulation pumped at a high or low pressure? Why?

The pulmonary circulation is pumped at a low pressure. Not much force is required to send blood the short distance through the lungs from the right to the left heart and high pressure in pulmonary capillaries would force fluid out of the blood, into the lung tissue and we would drown.


In pulmonary circulation, blood leaves the right ventricle through what?

The pulmonary arteries.


In pulmonary circulation, blood returns to the heart from the lungs through what vessels?

Pulmonary veins.


In pulmonary circulation, blood enters which chamber of the heart after returning from the lungs?

The left atrium.


In pulmonary circulation what does the pulmonary trunk divide into?

The right and left pulmonary arteries.


Define Systemic.

Affecting the whole body.


Which chamber of the heart is the origin of systemic circulation?

The left ventricle.