Thorax IV

Question 1

Describe the cardiac skeleton

Answer 1

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

Question 2

Label this. What is it?

Answer 2

The cardiac skeleton

Question 3

Label this, what is it?

Answer 3

Another cardiac skeleton

Question 4

Describe the tricuspid valve

Answer 4

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)

Question 5

Label this

Answer 5

Question 6

What is the septomarginal trabecula?

Answer 6

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

Question 7

Label this, what is it?

Answer 7

The aortic sinuses fill w blood. Coronary arteries found w/in the coronary sinus

Question 8

What are the heart ascultation points?

Answer 8

Question 9

Label the major veins of the thorax

Answer 9

Question 10

Label and explain this diagram

Answer 10

L and R brachiocephalic will join juntos to form the SVC

R and L common iliac join juntos to form the IVC

Question 11

Describe the thymus

Answer 11

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

Question 12

Describe the lymphatic system

Answer 12

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.

Question 13

Label this

Answer 13

Question 14

Describe lymphatic drainage of the thorax

Answer 14

Question 15

What is the thoracic duct?

Answer 15

Question 16

Describe the symp ns within the thorax

Answer 16

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

Question 17

What are thoracic sphlanic nerves?

Answer 17

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

Question 18

Describe the different thoracic splanchic nerves

Answer 18

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

Question 19

What are the phrenic nerves?

Answer 19

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

Question 20

Label this

Answer 20

Question 21

Describe the vagus nerve

Answer 21

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