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ANA 113 Lecture 27
Respiratory Lecture 2
| Question | Answer |
|---|---|
| Medial surface of the lungs | (hilum) region where pulmonary vessels and bronchi pass into lung tissue |
| Costal surface of lungs | in contact with ribs, anterior surface |
| Apex of lungs | superior most, extends above the clavicle |
| Base of lungs | inferior most, fits over convex dome of the diaphragm |
| Pleura | double walled sac which encloses and protects the lungs. composed of a serous membrane which secretes pleural fluid |
| Viseral pleura | adheres directly to the surface of the lung |
| Parietal pleura | lines the walls of the thoracic cavity |
| Pleural cavity | the space between the visceral and parietal pleural membranes which contains pleural fluid for lubrication |
| Pleurisy | infection of the pleural membranes |
| Midclavicular line: where does the lung end? where does the pleura end? where can you remove pleural fluid from? | Lung: rib 6, Pleura: rib 8, remove from: rib 7 |
| Midaxillary line: where does the lung end? where does the pleura end? where can you remove pleural fluid from? | Lung: rib 8, Pleura: rib 10, remove from: rib 9 |
| Midscapular line: where does the lung end? where does the pleura end? where can you remove pleural fluid from? | Lung: rib 10, Pleura: rib 12, remove from: rib 11 |
| What happens if you aim too low while trying to remove pleural fluid on the left side? | you'll hit the spleen |
| How many lobes are on the right side? | 3: superior, middle, inferior |
| How many lobes are on the left side? | 2: superior, inferior |
| Bronchoplumonary segments | smaller divisions of the lobes of lung tissue |
| What supplies each bronchopulmonary segment? | tertiary bronchus, pulmonary arteriole and pulmonary venule |
| How many alveoli/lung are there? | approximately 350 million per lung |
| Structure of alveoli | -small grape-like clusters of sacs where gas exchange occurs -composed of type I and type II cells |
| Type I cells | located in alveoli-simple squamous cells |
| Type II cells | located in alveoli- cells that produce a "detergent-like" substance called surfactant which prevents alveolar walls from sticking together and collapsing |
| Surfactant | prevents alveolar walls from sticking together and collapsing |
| Main muscle of respiration | diaphragm |
| What innervates th diaphragm? | phrenic nerve (originates from C3, C4, C5) |
| Diaphragm | -thin dome shaped sheet of skeletal muscle -seperates thoracic and abdominal cavities |
| Hiatus | openings in the diaphragm that allow for the passage of the aorta, the inferior vena cava and the esophagus from the thoracic cavity to the abdominal cavity |
| Where is the respiratory center located? | hypothalmus |
| What controls contraction of the diaphragm and intercoastal muscles? | CNS and PNS motor neurons |
| Where are the motor neurons? | upper motor neuron from CNS (frontal lobe) and lower motor neuron in ventral gray horn of spinal cord |
| What do baroreceptors respond to? | pressure changes, stretch, temperature changes |
| How does the hypothalmus affect the rate of breathing besides being the respiratory center? | other things controlled by hypothalmus may also affect rate of breathing; emotions, stress, pain, etc. |
| Peripheral chemoreceptors | -coracoid body (near bifurcation) and aortic bodies (near aortic arch) respond to changes in pH (due to CO2) levels -CN IX and X transmit messae to brain stem |
| How does CO2 affect the rate of respiration? | CO2 levels increase, pH decreases, respiration rate increases *rate of respiration is affected by the amount of CO2 in the body, NOT by the amount of oxygen you need |
| Pneumothorax | introduction of air into the plueral cavity due to stabbing, rib fracture, attempt to insert a tube into subclavian vein, etc. causes the lung to collapse |
| Inspiraion | (movement of air into lungs) acheived through contraction of the diaphragm (flatten/lower dome) and contraction of the intercoastal muscles (ribs move up and out-elevtion of ribs) |
| Expiration | (movement of air out of lungs) acheived through passive recoil (muscles relax) and forced expiration (contraction of specific muscles) |
| Passive elastic recoil | -expiration by relaxation of muscles -relaxation of skeletal muscle of the diaphragm (it rises) -relaxation of intercoastals (ribs move down and inward) -result: decreases vertical dimension of the thoracic cavity, increases pressure, air moves out |
| Forced expiration | -contraction of specific muscles -abdominal muscles contract and push organs upward, further decreases size of the thoracic cavity to force more air out. |