Questions and Answers
What structure accompanies the anterior interventricular artery?
Where does the middle cardiac vein open?
What does the oblique vein of the left atrium merge with?
Which veins empty directly into the auricles of the right atrium?
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What type of neural control increases the rate and force of heart contractions?
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What is the primary function of parasympathetic nerves in heart innervation?
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What is the inner layer of the heart wall called?
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What type of veins are the smallest cardiac veins (venae cordis minimae)?
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What is the primary boundary that closes the thoracic cavity inferiorly?
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Which of the following best describes the mediastinum?
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Which structure is NOT a content of the superior mediastinum?
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The inferior mediastinum can be sub-divided into how many parts?
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Which nerve is associated with the structures located within the superior mediastinum?
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What is the location of the anterior mediastinum?
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Which of the following structures is a content of the superior mediastinum listed in order from anterior to posterior?
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Which structure is part of the inferior mediastinum?
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What is the outer layer of the heart wall called?
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What type of epithelium is found in the endothelial lining of the endocardium?
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Which layer of the heart wall is composed of cardiac muscle cells?
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Where are Purkinje fibers located?
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What is the primary function of intercalated disks in cardiac muscle cells?
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Which chamber of the heart has the thickest myocardial layer?
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Which layer is the thinnest part of the heart wall?
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What distinguishes myocardial cells from smooth or skeletal muscle cells?
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What is the primary function of muscular arteries?
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Which characteristic best describes arterioles?
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What distinguishes fenestrated capillaries from other types of capillaries?
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Which type of capillary is known for being very leaky and having large lumens?
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What is the main role of the tunica media in muscular arteries?
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Which statement about continuous capillaries is TRUE?
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What feature of arterioles allows them to control blood flow into capillaries?
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What type of capillary would you expect to find in the kidney glomeruli?
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What is the primary function of intercalated discs in cardiac muscle tissue?
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Which layer of the heart is comprised primarily of connective tissue and mesothelium?
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What is the main purpose of the tunica media in blood vessels?
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Which type of blood vessel has thick walls and is located near the heart?
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Which component of blood vessel structure is primarily composed of smooth muscle cells?
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What is the role of elastin fibers in elastic arteries?
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What type of connective tissue in the tunica externa provides structural support?
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Which element is NOT a component of the tunica intima in blood vessels?
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Study Notes
Thoracic Cavity
- Cone-shaped space bounded by the thoracic wall, open to the neck and closed by the diaphragm.
- Divided into three sections: two pleural cavities (right and left) and the mediastinum.
Divisions of the Thoracic Cavity
- Pleural Cavities: Lateral parts containing the lungs.
- Mediastinum: Large space between the pleural cavities, housing various vital structures.
Mediastinum
- Extends from the sternum anteriorly to the vertebral column posteriorly, and from the thoracic inlet superiorly to the diaphragm inferiorly.
- Divided by an imaginary transverse thoracic plane into superior and inferior mediastinum.
Superior Mediastinum
- Contains structures from anterior to posterior:
- Upper part of the thymus.
- Major vessels: left brachiocephalic vein, upper half of the superior vena cava, arch of the aorta and its branches.
- Nerves: vagus, phrenic, left recurrent laryngeal nerve, cardiac plexus.
- Trachea and upper esophagus.
- Sympathetic trunk.
Inferior Mediastinum
- Extends from the transverse thoracic plane to the diaphragm.
- Subdivided into anterior, middle, and posterior mediastinum by the fibrous pericardium.
Anterior Mediastinum
- Located behind the sternum and anterior to the fibrous pericardium.
- Contains remains of thymus, sternopericardial ligaments, and parasternal lymph nodes.
Middle Mediastinum
- Houses the heart and great vessels.
Posterior Mediastinum
- Contains structures such as the thoracic aorta, esophagus, and associated nerves.
Cardiac Veins
- Coronary Sinus: Receives blood from the middle cardiac vein and anterior cardiac vein along with smallest cardiac veins.
- Great Cardiac Vein: Merges with the oblique vein of the left atrium.
Lymphatic Drainage of Heart
- Lymphatic vessels from myocardium drain into subepicardial plexus then into thoracic duct.
Heart Innervation
- Parasympathetic: Via vagus nerve; decreases heart rate and constricts arteries.
- Sympathetic: From sympathetic chain; increases heart rate and dilates coronary arteries.
Histology of the Heart
- Structured in three layers:
- Endocardium: Inner layer with simple squamous epithelium and connective tissue; hosts Purkinje fibers.
- Myocardium: Thickest layer composed of cardiac muscle, especially in the left ventricle.
- Epicardium: Outermost layer consisting of connective tissue, vessels, and mesothelium.
Blood Vessels Structure
- Composed of three tunics:
- Tunica Interna: Endothelial lining and subendothelial layer.
- Tunica Media: Smooth muscle and elastic fibers.
- Tunica Externa: Mainly collagenous fibers.
Types of Blood Vessels
- Elastic Arteries: Thick-walled near the heart, containing elastin fibers for pressure regulation (e.g., aorta).
- Muscular (Distributing) Arteries: Deliver blood to organs; thick tunica media predominated by smooth muscle.
- Arterioles: Smallest arteries controlling blood flow into capillary beds.
Capillaries
- Continuous Capillaries: Tight junctions, found in muscle, nervous tissue; less permeable to large molecules.
- Fenestrated Capillaries: Pores present, highly permeable, located in intestines, kidneys.
- Sinusoids: Very leaky, large lumens found in liver and lymphoid tissue, allowing for slow blood flow and modification.
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Description
This quiz covers the basics of the thoracic cavity and its importance in the cardiovascular system. Explore the distinct divisions and structures within the thoracic cavity, including the pleural cavities. Perfect for students studying clinical anatomy.
