Heart And Mediastinum Flashcards
What are the superior, inferior, anterior, posterior, and lateral boundaries of the mediastinum?
Superior: thoracic inlet
Inferior: diaphragm
Anterior: sternum and costal cartilages
Posterior: thoracic vertebrae
Lateral: pleura
Which of the following structure(s) is/are found in the middle part of the inferior mediastinum?
A) fat and lymph tissue B) cardiac and autonomic nerve plexuses C) the heart and its pericardial tissues D) the thoracic aorta E) thoracic splanchnic nerves
C
What is found in the superior area of the mediastinum?
-great heart vessels, thoracic duct, azygos system, vagus nerves, pulmonary, esophageal and cardiac autonomic plexuses, thymus, parts of trachea and esophagus
What is found in the inferior anterior of the mediastinum?
Fat, lymph tissue, vessels, in small children the thy,us may extend into this region
What can be found in the middle inferior portion of the mediastinum?
-the heart and its pericardial tissues
What can be found in the inferior posterior portion of the mediastinum?
-thoracic aorta, esophagus, pulmonary arteries and veins, azygos system, thoracic duct, sympathetic trunk and thoracic splanchnic nerves
Describe the sympathetic trunk relation to the mediastin.
- bilateral: continuous with the cervical and lumbar parts of the spinal cord
- paravertebral ganglia along its course
- lateral to vertebral bodies
Describe the thoracic splanchnic nerves in comparison to the mediastinum.
- bilateral: emerges from sympathetic trunks
- greater, lesser, least
- all three are part of the abdominopelvic splanchnic nerves and provide sympathetic innervation to the viscera inferior to the diaphragm
- all PREsynaptic fibers will synapse with prevertebral ganglia in abdomen
What are the areas where a swallowed foreign object will most likely lodge?
- areas of constriction
- arch of aorta
- left main bronchus
- diaphragm
What are the three more important venous structures in the mediastinum?
- accessory hemiazygous vein
- azygos vein
- hemiazygous vein
What are the functions of the heart?
- center f the cardiovascular system
- connects the blood vessels that transport blood between the heart and the other body tissues
What direction do arteries and veins transport blood? Which has more oxygen? What is the exception?
- arteries carry blood away from the heart, oxygenated blood
- veins carry blood to the heart, deoxygenated blood
- exception is the pulmonary arteries and veins
Arteries and veins entering and leaving the heart are called the _________________.
-great vessels
What are some characteristics of the heart?
- ensures unidirectional flow of blood
- back flow of blood is prevented by valves
- acts like two independent, side by side pumps that work independently but at the same rate
- develops bp
- min bp is essential to push blood through vessels to the body tissues
Where, anatomically, is the heart?
- size of a person’s fist
- located left of the body midline posterior to the sternum in the middle mediastinum
- right side is more anterior, left side is more posterior
The base of the heart is primarily formed by the?
A) right atrium B) left atrium C) right ventricle D) left ventricle E) coronary sinus
B
The pericardium of the heart has three primary layers. If the pericardium of the heart is pierced by a needle, which of these primary layers would the needle first pass through?
A) visceral pericardium B) pleural pericardium C) parietal pericardium D) fibrous pericardium E) epicardium
D
What is the function of the pericardium?
- restricts heart movements so that it doesn’t bounce and move around in the thoracic cavity
- prevents heart from overfilling with blood
What are the layers of the pericardium from the outermost to the inner most?
- fibrous pericardium
- parietal layer
- visceral layer
What are the three layers of heart wall?
- external epicardium
- middle myocardium
- internal endocardium
What is the epicardium also known as?
-visceral layer of serous pericardium
What happens to the epicardium as we age?
-the layer becomes thicker and fattier
What layer of the heart wall is the thickest?
-myocardium
Between the endocardium and myocardium lies a subendocardial layer which is composed of _____________ CT.
Areolar
What is the auricle?
A wrinkled, flap like extension anterior to the atrium
Which of the following structure(s) make(s) up the superior boundary of the mediastinum?
A) pleura B) diaphragm C) thoracic membrane D) thoracic inlet E) Costal cartilage
D
What are the arteries that carry blood from the the ventricles?
- pulmonary trunk (right ventricle)
- aorta (left ventricle)
Atria are separated externally by what?
- coronary sulcus or AV sulcus
- extends around the circumference of the heart
What is located between the left and right ventricles?
- anterior interventricular sulcus
- posterior interventricular sulcus
- extend from coronary sulcus toward the apex of the heart
Where is the fibrous skeleton of the heart located? What types of tissue makes up the skeleton?
- between the atria and ventricles
- dense irregular CT
What does the fibrous skeleton of the heart do?
-separates the atria and ventricles
-anchors heart valves by forming supportive rings at their attachment sites
-provides electrical isolation
+insulation ensures that muscle impulses are not spread randomly throughout the heart, preventing the heart chambers from contracting at the same time
-provides a rigid framework for the attachment of the cardiac muscle
In the adult heart, the fossa ovalis can be viewed in the:
A) right atrium B) left atrium C) right ventricle D)left ventricle E) cannot be viewed in the adult heart bc it's a fetal structure
A
What are the three major vessels that drain into the right atrium?
- superior vena cava
- inferior vena cava
- coronary sinus (drains heart wall)
What is the wall between the left and right atria called? What muscle type does the atria contain?
- interatrial septum
- pectinate muscle
Atrioventricular valves function similar to the:
A) pulmonary valve
B) aortic valve
C) venous valves
D) arterial valves
C
What are the two AV valves called? Sides? When do they close?
- tricuspid -> right
- bicuspid/mitral -> left
- valves are forced closed when the ventricle contracts, preventing back flow of blood into the atrium
What are the cone-shaped muscular structures in the ventricles called? What do they anchor?
- papillary muscle
- chordate tendinae: attach to the cusp of the AV valve and prevent everything the flipping into the atrium during contraction
What is the superior end of the pulmonary trunk called?
-conus arteriosus: narrows into smooth walled, conical region
What is the name of the valve separating the right ventricle and the pulmonary trunk?
-pulmonary semilunar valve
Describe semilunar valves.
- three thin, pocket-like cusps
- when ventricular contraction ceases, blood is prevented from flowing back into the ventricles from the arterial trunk by first entering the pockets of the semilunar valves between the cusp and the chamber wall
Which of the four chambers is the largest?
-left ventricle -> 3x thicker than the right ventricle (must be strong to pump to all of the body)
What structure is most prominent in the left ventricle?
-trabeculae carneae
Differentiate between sympathetic and parasympathetic innervation of the heart.
Sympathetic:
- increase HR
- strengthens force of contraction
Parasympathetic:
- decreases HR
- no effect on force of contraction except in special circumstances
What is the parasympathetic nerve? Sympathetic?
- para: vagus nerve
- sym: sympathetic cardiac nerve
What does the right coronary artery branch into? What does each artery supply?
- marginal artery (supplies rt border of the heart)
- posterior interventricular artery (supplies both left and right ventricles?
The left coronary artery typically branches into the:
A) marginal artery
B) anterior interventricular artery
C) posterior interventricular artery
D) lateral artery
B
What does the left coronary artery branch into? What do these arteries supply?
- anterior interventricular artery/left anterior descending artery (supplies anterior surface of both ventricles and most of interventricular septum)
- circumflex artery (supplies left atrium and ventricle)
What is cardiomyopathy? What are the two types?
- a condition in which the ventricle has become enlarged and thickened and/or stiffened.
- dilated: enlarged, weakened left ventricle struggles to pump enough blood to meet body’s needs
- hypertrophic: left ventricle cannot fully relax between heartbeats, resulting in less blood flow
What are the two vessels used in a coronary artery bypass?
- saphenous vein
- internal mammary artery
What is an angioplasty?
- a procedure in which a catheter is inserted with a tiny balloon that presses the plaque blockage against the artery so that blood may flow more freely.
- a stent is then inserted to keep the vessel pathway open and the blood flowing
