Lab 4 - Thorax Flashcards
Which ribs are true?
1-7
False?
8-10
Floating?
11,12
What determines these distinctions?
How/if they attach to the sternum
How are the ribs attached to the sternum and what are these joints called?
Via costal cartilages
What parts of the rib articulate with the thoracic vertebrae? What are these joints called?
Head (articulate with demifacets of vertebral bodies) & Tubercule (articulate with transverse process of vertebra)
What is found within the costal groove?
Intercostal neuromuscular bundle
Which structures pass through the thoracic inlet?
- Closed off by diaphragm
- Esophagus
- Inferior vena cava
- Aorta
Through the thoracic outlet?
- Esophagus
- Trachea
- Vessels & nerves of head & neck
- Vessels of upper limbs
- Apex of lungs
What are the actions of these muscles on the ribs? Are they active during inspiration or expiration?
Diaphragm
Action: primary muscle of inspiration
Active during both
What are the actions of these muscles on the ribs? Are they active during inspiration or expiration?
- External intercostals
Action: elevate ribs during FORCED INSPRATION
What are the actions of these muscles on the ribs? Are they active during inspiration or expiration?
- Internal intercostals
Action: depress ribs during FORCED EXPIRATION
What are the actions of these muscles on the ribs? Are they active during inspiration or expiration?
- Innermost intercostals
Action: depress ribs during FORCED EXPIRATION
What nerves innervate these muscles?
Phrenic nerves?
The intercostals and diagphragm are the obligatory (aka. essential) muscles of respiration. In our previous labs, we have seen several muscles that act as accessory muscles of respiration: sternocleidomastoid, pectoralis major, and the scalenes (anterior, middle, and posterior). Find these muscles again, and note their attachment to the ribs and sternum. How would these muscles affect respiration?
?
What are the pleural cavities lined with?
Serous epithelium with subepithelial connective tissue; 2 continuous parts: Parietal pleura, Visceral pleura
Where is the costo-diaphragmatic recess and what is its significance?
Pleura cavity b/t pleural reflection & lung border
Which bronchus is wider, shorter, and more vertical? Of what significance might this be?
Right primary bronchus (for the 3 lobes)
What structures are found at the hilum of the lung?
- Pulmonary arteries
- Primary bronchi
- Pulmonary veins
- Bronchial arteries & veins
- Lymph nodes & lymphatic vessels
- Nerves
What structure does the phrenic nerve innervate?
Diaphragm
What structures does the vagus nerve innervate in the thorax?
Parasympthatic to autonomic nerve plexuses (cardiac, pulmonary, esophageal) ?
There are 3 openings in the diaphragm. What structures pass through these openings?
- Caval opening for inferior vena cava
- Esophageal hiatus for esophagus
- Aortic hiatus for aorta
Which layer is attached to the diaphragm?
Fibrous pericardium ?
What is found between the two layers of serous pericardium?
Pericardial cavity
What clinical condition can occur if there is a build-up of this substance within the pericardial sac?
Cardiac tamponade ?
Right atrium:
Identify the pectinate muscles, the openings of the superior and inferior venae cavae, the coronary sinus, and the atrioventricular orifice.
Right ventricle:
Identify the trabeculae carnae, the moderator band, the tricuspid valve, chordae tendinae, papillary muscles, and the pulmonary valve.
Left atrium: (note its smooth interior surface).
Identify the openings of the four pulmonary veins and the atrioventricular orifice.
Left ventricle:
Identify the trabeculae carnae, the mitral valve, anterior and posterior papillary muscles, chordae tendinae, and the aortic valve.
Which ventricular wall is thicker? Why?
LV
Has membranous and muscular part because pumps blood (main powerhouse) ?
How do the cuspid valves prevent regurgitation of blood into the atria?
When the ventricle contracts, the pressure of the blood drives the AV valve cusps upward until their edges meet, closing the AV orifice
* Papillary muscles also contract & pull the chordae tendineae taut
* This prevents the valve cusps from being pushed into the atrium
* If the AV valves or chordae tendineae are damaged, blood may regurgitate into the atria
How do the semi-lunar valves work?
Allow ejection of blood from ventricles into arteries but prevent back flow of blood
* When the ventricle contracts, blood pressure pushes open the semilunar valve
* When the ventricles relaxes, blood is pushed back towards the ventricle & fill the sinuses behind semilunar cusps
o Free edges of cusps are pushed together, nodules seal the center, closing the opening
What are the branches of the brachiocephalic trunk? What do they supply?
Left Subclavian a. and Right Subclavian a. ?
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Find the left and right brachiocephalic veins. What structure do they form when they merge in the superior mediastinum?
SVC
Right coronary artery
major branches
right marginal artery and posterior interventricular artery.
Left coronary artery
major branches
anterior interventricular artery and circumflex artery.
Which regions of the heart do these arterial branches supply?
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Where does the coronary sinus terminate? ??
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