Heart & Mediastinum Flashcards
What makes up the inferior boundary of the mediastinum?
Diaphragm
What makes up the anterior boundary of the mediastinum?
Sternum and costal cartilages
What makes up the posterior boundary of the mediastinum?
Thoarcic vertebrae
What makes up the lateral boundary of the mediastinum?
Pleura
What structures are found in the superior part of the mediastinum?
Vessels of the heart
Thoracic duct
Azygous system
Vagust nerves
Pulmonary, esophageal, cardiac & autonomic nerve plexuses
Thymus
Parts of trachea and esophagus
What is found in the inferior anterior art of the mediastinum?
Fat
Lymph tissue
Vessels
Thymus
What is found in the inferior middle part of the mediastinum?
The heart and its pericardial tissues
What is found in the inferior posterior part of the mediastinum?
Thoracic aorta
Esophagus
Pulmonary arteries and veins
Azygous system
Thoracic duct
Sympathetic trunk and thoracic splanchnic nerves
What are some arteries that are found in the mediastinum?
Brachioccephalic trunk
Left common carotid artery
Left subclavian artery
What are some nerves that are found in the mediastinum?
Phrenic nerve
Vagus nerve
Left recurrent laryngeal nerve
Sympathetic trunk
The thoracic sympathetic trunk is bilateral. It is continuous with ___ and ___ parts of the sympathetic trunk.
The thoracic sympathetic trunk is bilateral. It is continuous with cervical and lateral parts of the sympathetic trunk.
What type of ganglia run rlong the course of the mediastinum?
Paravertebral ganglia.
What is the mediastinum lateral to?
Vertebral bodies
What do the thoracic splanchnic nerves emerge from?
Thoracic sympathetic trunks.
What do the greater, lesser and least thoracic splanchnic nerves provide sympathetic innervation to?
Viscera inferior to the diaphragm.
The thoracic splanchnic fibers are all presynaptic fibers. What do they synapse with?
Prevertebral ganglia in the abdomen.
The arch of aorta, left main bronchus and the diraphragm are all areas of ______ where swallowed foreign objects are most likely to lodge and where a stricture may develop (e.g. After drinking a caustic liquid).
Constriction
Arteries carry blood ___ from the heart
Away
Veins carry blood ____ the heart
To the heart
Arteries carry blood ____ in oxygen (except for the pulmonary arteries).
High
Veins carry blood ____ in oxygen (except for the pulmonary veins).
Low
What are arteries and veins entering and leaving the heart called?
Great vessels.
Backflow of blood is prevented by what structures found within the heart?
Valves
What are the functions of the two independent, side-by-side pumps found in the heart?
One directs blood to the lungs for gas exchange.
The other directs blood to body tissues for nutrient delivery.
Alternate cycyles of heart wall contraction and relaxation produce what?
Blood pressure
What does the pulmonary circuit consist of?
Chambers on the right side of the heart (right atrium and ventricle) as well as the pulmonary arteries and veins.
What is the function of the pulmonary circuit?
It conveys blood to the lungs via pulmonary arties to reduce carbon dioxie and replenish oxygen levels in the blood before returning to the heart in pulmonary veins.
Blood that returns to the left side of the heart enters what circuit?
The systemic circuit
What does the systemic circuit consist of?
Chambers on the left side of the heart, along with all the other named blood vessels.
What is the function of the systemic circuit?
It carries blood to tall the peripheral organs and tissues of the body.
What is the largest systemic artery in the body?
Aorta.
Oxygenated blood from the left side of the herat is pumped into the aorta, and then into smaller systemic arteries.
Where does gas exchange in tissues occur?
From capillaries.
Most veins merge and drain into what vessel?
Superior and inferior vena cavae.
These two drain blood into the right atrium.
There, blood enters the pulmonary circuit and the cycle repeats.
In what portion of the mediastinum is the heart located?
Middle mediastinum.
How is the heart rotated in the body?
It is rotated such that its ride side or border (right atrium and ventricle) is located more anteriorly, while its left side or border (left atrium and ventricle) is located more posteriorly.
The base of the heart is primarily formed by the
Left atrium.
It is also known as the posterosuperior surface of the heart.
What is the inferior, conical end of the heart called?
The apex.
It projcts slightly anteoinferiorly toward the left side of the body.
The pericardium of the heart has three primary layers. If the pericardium of the heart is pierced by a needle, which of the primary layers would the needle first pass through?
Fibrous pericardium
What is the inner portion of the pericardium called?
Serous pericardium.
It contains a parietal and visceral layer.
What is the function of the pericardium?
It supports the the external walls superior to the heart and the diaphragm inferior to it.
It also restricts heart movements and prevents the heart from overfilling with blood.
What are the three layers of the heart wall?
External epicardium
Middle myocardium
Internal endocardium
What is the epicardium (outermost heart layer) also known as?
It is also known as the visceral layer of serous pericardium.
Which layer of the heart wall is composed mostly of cardiac muscle tissue?
Myocardium
Which layer of the heart wall covers the internal surface of the heart and external surfaces of heart valves?
Endocardium.
Between the endocardium and myocardium lies a subendocardial layer, which is composed of areolar connective tissue.
What are the four chambers of the heart?
Two atria (small)
Two ventricles (large)
Where are atria located in relation to the heart?
They are located superiorly.
What is an auricle?
A wrinkled, flaplike extension of the anterior part of each atrium.
True or false: the atria receive blood returning to the heart through the systemic circuit only.
False;
The atria receive blood returning to the hear through both circulatory circuits.
The right atrium receives blood from the ___ circuit.
Systemic
The left atrium receives blood from the ___ circuit.
Pulmonary
Blood that enters an atrium is passed to the ventricle on the _____ of the heart.
Blood that enters an atrium is passed to the ventricle on the SAME side of the heart.
Where are ventricles located in relation to the heart?
They are inferior chambers.
On what surface to the pulmonary trunk and the aorta exit the heart?
The basal surface
The pulmonary trunk carries blood from the ____ into the pulmonary circuit.
Right ventricle
The aorta conducts blood from the ______ into the systemic circuit.
Left ventricle
What separates the atria from the ventricles externally?
The deep coronary sulcus (or atrioventricular sulcus)
What are the anterior interventricular and the posterior interventricular sulci located between?
The left and right ventricles
The anterior and posterior interventricular sulci extend inferiorly from the coronary sulcus toward the ___
The anterior and posterior interventriular sulci extend inferiorly from the coronary sulcus toward the HEART APEX.
Where is the fibrous heart skeleton located?
Between the atria and the ventricles. It functions to separate the atria and ventricles.
What is the fibrous heart skeleton formed from?
Dense irregular connective tissue.
What are functions of the fibrous heart skeleton?
It separates the atria and ventricles
Anchors heart valves by forming supportive rings at their attachment points.
Provides electrical insulation between atria and ventricles
Prevents all of the heart chambers from beating at the same time.
Provides a rigid framework for the attachment of cardiac muscle tissue.
What are the four chambers of the heart?
Right/left atrium
Right/left ventricle
What are the three major vessels that empty into the right atrium?
Superior vena cava (from head, upper limbs and superior reigons of the trunk)
Inferior vena cava (from lower limbs and trunk)
Coronary sinus (from heart wall)
In the adult heart, the fossa ovalis can be viewed in the ?
Right atrium
What forms a wall between the right and left atria?
Interartial septum
What type of muscle is found in the right atrium?
Pectinate muscle
What is the function of the right atrioventricular valve?
It separates the right atrium from the right ventricle.
What is another name for the right atrioventricular valve?
Tricuspid valve
What is the floow of blood through the right AV valve?
Right atrium -> AV valve -> right ventricle.
When is the AV valve forced closed?
When the right ventricle begins to contract.
This prevents blood backflow into the right atrium.
What receives deoxygenated blood from the right atrium?
The right ventricle.
What forms a wall between the right and left ventricles?
Interventricular septum
What are papillary muscles?
They are muscles found in the internal wall surface of each ventricle.
They anchor chordae tendineae.
They also attach to the cusp of the right AV valvue and prevent everting and flipping into the atrium when contracting.
The superior end of the pulmonary trunk narrows into what region?
The conus arteriosus.
What is the significance of the pulmonary semilunar valve?
It marks the end of the right ventricle and the entrance into the pulmonary trunk.
What does the pulmonary trunk divide into?
Right and left pulmonary arteries, which carry deoxygenated blood to the lungs.
Atrioventricular valves function simular to the
Pulmonary valve
Where are semilunar valves located?
Within the walls of both ventricles immediately before the connection of the ventricle to the pulmonary trunk and aorta.
Each is composed on three thin, pocketlike semilunar cusps.
How do semilunar valves function?
As blood is pumped ino the arterial trunks, it pushes against the cusps of the valves, forcing the valves open.
When contraction ceases, blood is prevented from flowing back into the ventricles by entering the pockets of the semilunar valves between the cusp and chamber wall. This causes the cusps to inflate and meet at the artery center, effectively blockinb lood backflow.
Once gas exchange occurs in the lungs, where does the oxygenated blood travel?
Through the pulmonary veins to the left atrium.
What does the left AV valve separate?
The left atrium from the left ventricle.
What is another term for the left AV valve?
Bicuspid valve or the mitral valve
What is a similarity between the left and right AV valves?
Both have chordae tendineae
What is the flow of oxygenated blood from the left atrium?
It flows into the left ventricle.
It is forced closed when the left ventricle begins to contract. This prevents blood backflow into the left atrium.
Which chamber is the learges of the four heart chambers?
Left ventricle
Why is the wall of the left ventricle so thick?
In order to generate enough pressure to force the oxygenated blood from the lungs into the aorta and then through the entire systemic circuit.
This is opposed to the right ventricle, which only has to pump blood to the nearby lungs.
What are the two large muscles that support the left AV valve?
Papillary muscles.
They attach to the chordae tendineae.
What does the aortic semilunar valve mark the end of?
The left ventricle and the entrance into the aorta.
What is the heart innervated by?
The autonomic nervous system.
What are the sympathetic and parasympathetic components of the heart collectively referred to as?
The cardiac or coronary plexus
What type of innervation to the heart increases the rate and force of heart contractions?
Sympathetic innervation
What type of innervaiton decreases heart rate, but tends to have no effect on the force of contractions, except in special circumstances?
Parasympathetic innervation
What do left and right coronary arties supply?
The heart wall.
They do so by traveling through the coronary sulcus.
Where are openings for the arteries located?
Immediately superior to the aortic semilunar valve.
What does the right coronary artery branch into?
Marginal artery (supplies the right side of the heart)
Posterior interventricular artery (suppleis both the right and left ventricles).
The left coronary artery typically branches into the:
Anterior interventricular artery
Circumflex artery
What is another tem for the anterior interventricular artery?
Left anterior descending artery.
What does the aterior interventricular artery supply?
The anterior surface of both ventricles and most of the interventricular septum.
What does the circumflex artery supply?
The left atrium and ventricle.
True or false: arterial pattern can vary greatly among individuals.
True
You encounter a patient with an abnormally low heart rate. Tests indicated that the left ventricle is enlarged and weakened, resulting in less blood being pumped. What does the patient most likely suffer from?
Dilated cardiomyopathy
You encounter a patient who has a low heart beat. Tests indicated that the left ventricle is thickened and stiff and does not fully relax between heartbeats. What does the patient most likely suffer from?
Hypertrophic cardiomyopathy
What is the condition in which a ventricle has become enlarged, thickened and/or stiffened, which subsequently reduces the heart’s ability to pump blood?
Cardiomyopathy
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 through the vessel.
A stend is then inserted to keep the vessel pathway open and the blood flowing.
What makes up the superior boundary of the mediastinum?
Thoracic inlet
