Thorax IV Flashcards
Describe the cardiac skeleton
4 rings of fibrous tissue which interconnect between the atria and ventricles
Surround the AV orifices, aortic orifice and opening of pulmonary trunk
Helps maintain integrity of openings and provides cusp attachments
Separates atria from ventricles, also electrically isolates the ventricles
The AV bundle is the single connection between these two groups of myocardium
Label this. What is it?
The cardiac skeleton
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Another cardiac skeleton
Describe the tricuspid valve
Sits between the RA and RV
Has 3 papillary muscles in right ventricle: Anterior: largest. Posterior: may consist of 1-3 structures. Septal: inconsistent (small or absent)
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What is the septomarginal trabecula?
Septomarginal trabecula (moderator band):
- Bridge between lower interventricular septum and base of anterior papillary muscle
- Carries a portion of the cardiac conduction system to anterior wall of right ventricle
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The aortic sinuses fill w blood. Coronary arteries found w/in the coronary sinus
What are the heart ascultation points?
Label the major veins of the thorax
Label and explain this diagram
L and R brachiocephalic will join juntos to form the SVC
R and L common iliac join juntos to form the IVC
Describe the thymus
Located in anterior portion of the superior mediastinum
Lies immediately posterior to the manubrium of the sternum
Lower apex typically extends into the anterior mediastinum over the pericardial sac
Blood supply: L+R internal thoracic arteries
Describe the lymphatic system
The lymphatic system is essentially a drainage system, no hay circulation
Before lymph is returned to the bloodstream, it passes through at least one lymph node, which filter lymph and have lymphocytes.
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Describe lymphatic drainage of the thorax
What is the thoracic duct?
Describe the symp ns within the thorax
Preganglionic sympathetic outflow from Spinal cord segments T1-L2 (Thoracolumbar outflow)
In these sympathetic chains, short preganglionic fibres synapse with roughly 30 postganglionic neurons. This facilitates divergence and more widespread response
What are thoracic sphlanic nerves?
The lower 8 ganglia of the sympathetic chain give pre-ganglionic fibres, which are grouped to form thoracic splanchnic nerves
Thoracic splanchnic nerves synapse in separate prevertebral ganglia, which run anterior to the vertebra (located around the blood vessels of the aorta)
Postganglionic fibres leave ganglia to innervate visceral tissues and organs within abdominopelvic cavity
Describe the different thoracic splanchic nerves
Greater Splanchnic nerve: T5-T9. Synapse in coeliac ganglion – Supplies foregut
Lesser Splanchnic nerve: T9/10- T12. Synapse in superior mesenteric ganglion. Supplies the midgut
Least Splanchnic nerve: T12. Synapses in aorticorenal ganglion. Supplies the kidneys
Lumbar splanchnic nerves: L1-L2. Synapse in the inferior mesenteric ganglion. Supplies hindgut
What are the phrenic nerves?
Originates from the cervical plexus
Contains motor, sensory, and sympathetic nerve fibers
Provides the only motor supply to the diaphragm as well as sensation to the central tendon. In the thorax, each phrenic nerve supplies the mediastinal pleura and pericardium
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Describe the vagus nerve
CNX. Autonomic control of the heart and digestive tract
Supplies motor parasymp fibers to all organs (except adrenal glands) from the neck to the second segment of the transverse colon
Controls a few skeletal muscles: Superior, middle and inferior pharyngeal constrictors. Muscles of the larynx
Travels in the carotid sheath w the internal jugular vein and carotid artery
Gives parasymp innervation to the SAN and AVN
