MEDIASTINUM AND HEART Flashcards
What is the mediastinum
space in chest between two lungs
What are the divisions of the mediastinum
Superior and Inferior (Anterior, middle, posterior)
What does the anterior mediastinum contain
Thymus until age 25 after that just fat and loose connective tissue
Where is the middle mediastinum and what does it contain
space confined by fibrous pericardium. Contain heart and main blood vessels joining to heart
What forms the floor and roof of the mediastinum
floor - diaphragm
Roof - Superior thoracic aperture (manubrium, first rib, and T1)
What makes up the super thoracic aperture
manubrium, first rib, and T1
what does the superior mediastinum contrain
- Trachea
- esophagus
- Arch of aorta
- Brachio-cephalic veins
- Thymus
- Vagus nerves
- Recurrent laryngeal nerves
- Azygus vein
- Pulmonary trunk
- Left pulmonary
- Descending aorta
Where does the arch of aorta form
at level of T4-T5 vertebral disc
When does the aorta enter the posterior mediastinum
when it turns into the descending aorta
____ join to form inferior vena cava
brachiocephalic veins
Where does the vagus nerve sit in the inferior mediastinum
in the posterior part
Where does the phrenic nerve pass in the inferior mediastinum
Middle mediastinum
Where in the inferior mediastinum is the thymus sitting
anterior
what are the 3 branches off the aorta
Brachiochephalic trunk
Left common carotid artery
Left subclavian artery
what joins to form the brachiocephalic vein
Internal jugular vein and subclavian vein
What does the posterior mediastinum contain
- Descending aorta
- Esophagus
- Sympathetic chains (para-vertebral ganglia)
- Azygus vein
- Thoracic duct
What are the branches of the ascending aorta
the coronary braches
what are ganglion
clusters of nerve cell bodies outside of the CNS
What are the nerves arising from the paravertebral ganglion and going towards the midline called
splanchnic
what does splanchnic mean
viscera
Which viscera do the splanchnic nerves supply
those in abdomen and below thorax
What are the sympathetic ganglion in the abdomen called
pre-vertebral ganglia
What is the name of vein travelling along the right side of the vertebral column
azygus
The azygus system is comprised of ___ azygus veins
3
In which mediastinum area is the azygus vein found
the posterior mediastinum
Right intercostal veins drain into the ____ -
azygus vein
Left intercostal veins drain into …
the accessory hemiazygus and hemiazygus veins and then into the azygus
Where does the accessory hemiazygus vein collect blood from
upper left thorax
Where does the hemiazygus vein collect blood from
lower left thorax
The azygus system eventually drains into.. t
the superior vena cava
What is the largest duct in the body
the thoracic duct
Where does the thoracic duct collect lymph from
the entire body except for the right upper limb, right half of head and neck, and the right half of chest
The right upper limb, right half of head and neck, and the right half of chest are drained by what
the right lymphatic duct
Where are the 4 angles of the heart located (surface anatomy)?
Upper right - 2nd intercostal space, 1 inch from sternum
Upper left - 2nd intercostal space 2 inches from sternum
Lower right - 5th intercostal space 1 inch from sternum
Lower left - 5th intercostal space 3 inches from sternum
Heart is surrounded by ___ layers of connective tissue. what are they?
3
Fibrous layer
Parietal serous pericardium
Visceral serous layer
What is the function of the fibrous layer of connective tissue surrounding the heart? what is it made up of?
Made up of dense irregular connective tissue
Provides some mechanical protection
What does the pericardial cavity contain? where is it located?
Located between the visceral and parietal serous layers. Contains a few drops of serous fluid to decrease friction while the heart is beating
What is inflammation of the pericardium called?
pericarditis
what occurs to patients with pericarditis
the pericardium starts to produce too much fluid and rapidly fills entire pericardial cavity - building pressure to the point where it stops the heart from beating
What are the surfaces of the heart
Anterior or sternalcostal
Right and left pulmonary surfaces
Base
Inferior or diaphragmatic surface
Where is the coronary sulcus
wrapping around heart separates atrium from ventricles
What does the coronary sulcus contain
coronary blood vessels (arteries and sinus)
The left coronary artery branches into…
the anterior interventricular artery and the circumflex artery
Where do you find fossa ovalis and what is it?
on the right wall of atrium - opening between left and right atrium which closes shortly after birth
The ovalis fossa does not close in ___% of people
15
What is the coronary sinus
large vein that returns venous blood to the right atrium
papillary muscles arise from ____ and attach to _____
the walls of the ventricles and attach to short tendon like structures called corda tendinae
Corda tendinae attach to..
tricuspid or bicuspid valves
What is the function of the papillary muscles
Contract with rest of ventricles and prevent back flow into the atrium by preventing cusps from flipping over
What is special about the muscle fibres of the heart
some of them can generate and send impulses like neurons
Can the muscles which send nerve impulses still contract like typical myocardial cells
yes! but not as well as the others
What initiates electrical impulses in the heart
the sinoatrial node
The sinoatrial node passes electrical impulses to…
the atrial ventricular node
The atriaventricular node passes impulses through ____
the AV bundle
The AV bundle divides into…
two bundles of his
The bundles of his divide into smaller fibres called…
purkinje fibers
What is the path of the right coronary artery
From ascending aorta it travels along coronary sulcus wraps around right side and reaches inferior surface and continues in posterior interventricular groove at which point I becomes the posterior interventricular artery
How many branches does the right coronary artery have
13
When do the coronary arteries get blood flow? why?
in Diastole - When the heart is in systole leafles are open and are covering the coronary arteries. In diastole the leaflets are relaxed and blood can flow into the coronary arteries
Does the heart receive more or less blood during exercise? why?
Less - the heart has shorter diastole phases - therefore the coronary arteries are covered by the leaflets for a greater percentage of the time - this is why you should not exceed HR max for more than a few mins
In __% of the population the rights coronary artery is more important than the left
70 %
The small or lesser cardiac vein sits where?
on right margin of heart
The middle cardiac vein sits where?
in posterior interventricular groove
Where is the great cardiac vein located
in anterior interventricular groove
where does myocardial infarction normally refer pain to
to the chest and left arm
Sensory autonomic innervation of the heart return to ____
T1-T4 segments of spinal cord
