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Thoracic Cavity
CCRI-Newport Q5
Question | Answer |
---|---|
2 lobes | The number of parts in a human left lung. |
3 lobes | The number of major parts of the lung on the right side in humans and number of parts on the left side in cats. |
4 lobes | The number of parts of the right lung in the cat. |
alveolar duct | The alveolar duct is the duct between the bronchiole and the alveoli. It lacks cartilaginous rings and cilia. At its terminus the alveolar duct leads to an alveolar sac. The alveolar sac is similar to a cluster of grapes, the grapes being the alveoli. |
alveolus | The alveoli are the functional units of the lungs. This is where the exchange of the respiratory gasses occurs. They are an example of miniaturization. Their combined surface area is about 1500 square feet. |
aorta | The great artery that carries blood away from the left ventricle to all the systemic arteries of the circulatory system. The blood in this artery is normally enriched with oxygen and deficient in carbon dioxide. |
arcuate ligament | The root “arc” refers to a curve. The arcuate ligament is the attachment of the diaphragm to the posterior abdominal wall and it has a curved shape. There is a lateral and medial arcuate ligament on each side and a central median arcuate ligament. |
autonomic nervous system | Operates without awareness of its activity. Its responsible for controlling viscera, cardiac muscle, and smooth muscles rather than skeletal muscles (somatic system). There are two subdivisions, the sympathetic and parasympathetic nervous systems. |
azygos vein | Drains the blood from the dorsal (posterior) thoracic wall into the cranial (superior) vena cava. Serves as an alternate path for the return of blood from caudal (inferior) to the diaphragm if the caudal (inferior) vena cava were to be blocked. |
bronchioles | Bronchioles are very small (smaller than 1 mm in diameter) respiratory tubes that lack the cartilaginous rings found in the larger bronchial tubes. Lack cilia and mucus secreting cells and terminate in the alveolar ducts, which lead to the alveoli. |
cardiac notch | The cardiac notch is found in the superior lobe of the left lung. It begins at the fourth costal cartilage and passes laterally. It is caused by the heart displacing the lung to the left. |
carina | The name for the ridge on the internal surface of the most inferior tracheal ring. It marks the point where the trachea bifurcates into the two primary bronchi. |
cartilaginous rings | These structures have their origin in the gill arches of the developing embryo. In fact they have the same origin as the cartilage of the larynx, the hyoid bone, and the mandible. They support the trachea and help prevent collapse. They are “C” shaped. |
central tendon | The name for the structure that serves as the insertion for the diaphragm. |
cervical spinal nerves 3, 4, and 5 | Origin of the Phrenic Nerve. |
connective tissue | There are many types of connective tissue. Functionally it is important because it plays a role in holding other tissues together, provides protection, insulates, plays a role in bulk flow, immunity, and storage of excess energy. |
cranial nerve X | The vagus nerve is cranial nerve X. It is the only cranial nerve to pass into the body cavities below the neck. It is primarily parasympathetic in nature and is the major nerve affecting the heart and most of the gastrointestinal tract. |
crura (crus) | The right crus secures the diaphragm to the bodies of lumbar vertebrae 1, 2, and 3. The left crus secures the diaphragm to the bodies of lumbar vertebrae 1 and 2. |
diaphragm | Primarily skeletal muscle. Responsible for most breathing at rest and is dome shaped. In humans- Origin: Its outer margin to the deep surface of the bony thorax. Insertion: central tendon. Nerve: Phrenic. |
esophagus | The esophagus is an organ that is primarily smooth muscle tissue. It is essentially a tube that extends from the pharynx to the stomach. Functionally it is important because it directs food from the pharynx to the stomach during swallowing. |
hiatal hernia | This is a condition where the esophagus tears free from the two crura (left and right). It usually occurs because the stomach has been pushed superiorly and forces a separation of the crura and esophagus. |
hyaline cartilage | It is found at articular surfaces of bones as well as forming the epiphyseal cartilage. It is tough and flexible, and at the articular surfaces very smooth. The smooth nature is important in reducing friction between the bones. |
insertion | The attachment of a skeletal muscle that USUALLY moves during the contraction of the muscle. The insertion is also USUALLY distal. |
left crus | Found at the level of Lumbar vertebrae 1 and 2. |
Lobules | The lobes are subdivided into lobules. They are functionally separate, but not physically separate. They vary in size from the size of a pencil eraser to the size of a penny. |
lubricate | to apply an oily or greasy substance to something in order to reduce friction to moving parts. |
lumbar vertebrae 1, 2, and 3 | Where the Rght Crus attaches to the diaphragm. |
lumbar vertebrae 1 and 2 | Where the Left Crus attaches to the diaphragm. |
mediastinum | The mediastinum is a subdivision of the thoracic cavity. Anterior boundary: parietal pleura, Laterally: pulmonary pleura, Inferiorly: diaphragmatic pleura. |
miniaturization | Increases surface area to volume ratio. Found in many organs. Important when secretion or absorption occur at the surface. |
oblique fissure | Each lung has an oblique fissure that separates the superior lobe from the inferior lobe. |
origin | The attachment of a skeletal muscle that USUALLY remains motionless during the contraction of the muscle. The origin is also USUALLY proximal. |
parasympathetic nervous system | The parasympathetic nervous system is one of the two functional subdivisions of the autonomic nervous system. It is responsible for the 'feed or breed' response. Nerves of this system are responsible for preparing the body for digestion and gestation. |
parietal pleura | This is the name for the pleura that covers the thoracic wall. See pleura. |
pericardium | The pericardium surrounds the heart. It is modified pleura, incorporating fibrous tissue as well as the normal pleural epithelial cells. It includes two layers rather than the usual single layer. |
phrenic nerve | The phrenic nerve is formed from the union of branches of the anterior rami of cervical spinal nerves 3, 4, and 5. It serves the diaphragm. |
pleura | The pleura is an organ that is primarily epithelial tissue. It covers the thoracic organs and lines the thoracic cavity. |
pleural fluid | Pleural fluid is a watery fluid produced by the pleura. The fluid comes from the blood. It has three major functions: lubrication, reducing heat buildup, and to create surface tension which causes the lungs to remain against the thoracic wall. |
pleural ligament | When pleura extends between organs, or between an organ and the thoracic wall. The ligaments are often two layers thick and we find structures such as veins, arteries, nerves and lymphatic ducts suspended between the layers. |
pleural recess | This is the space inferior to the lung where there is a pleural cavity. It may fill with fluid and can be drained by entering it superior to rib 9, midaxillary on either side. |
potential space | When two structures are touching each other, but are not physically attached we say there is a potential space between them. |
pulmonary pleura | The lateral boundary of the mediastinum. |
right crus | Found at the level of Lumbar vertebrae 1,2, and 3. |
somatic nervous system | Serves the skeletal muscles (except the pharyngeal arch muscles). We are aware of much of its activity, and often exert conscious control while it is active. |
sternal angle | This is the manubriosternal joint and is at the level between the bodies of thoracic vertebrae 4 and 5. It is an important landmark as it is where the costal cartilage of rib 2, the first rib that can be palpated, joins the sternum. |
sympathetic trunk | The sympathetic trunk runs along each side of the vertebral column. It receives neurons from anterior rami of the spinal nerves via the sympathetic trunk ganglia. It serves many organs from the head to the pelvis. |
thoracic duct | The thoracic duct (quack) is part of the lymphatic system. The constrictions in its walls are where the one way (semilunar) valves are. |
thymus gland | The thymus gland is part of the lymphatic system. It is situated cranial and ventral to the heart. It also functions as an endocrine gland. Functionally it is important because it preconditions T-lymphocytes. |
trachea | The trachea begins at the inferior end of the larynx (level of C6 body) and extends inferiorly to where it bifurcates into the left and right primary bronchi in humans. It has 16 to 20 cartilaginous rings that prevent it from collapsing. |
transverse fissure | Only the right lung has a transverse fissure that separates the superior lobe from the middle lobe of the lung. |
vagus nerve | The vagus nerve is cranial nerve X. It is the only cranial nerve to pass into the body cavities below the neck. It is primarily parasympathetic in nature and is the major nerve affecting the heart and most of the gastrointestinal tract. |
visceral pleura | This is the generic name for pleura that covers one of the organs. Its name will be derived from the organ it covers. For example, diaphragmatic pleura covers the diaphragm. See pleura. |