cardio-respiratory system Flashcards
What are the 3 functions of the respiratory system?
- ventilation (external)
- gas exchange (external and internal)
- oxygen utilization (internal)
What’s the role of the pulmonary alveoli?
Where gas exchange occurs
Why is there a large amount of pulmonary alveoli?
Creates large surface area for efficiency and effectivity
What are the two types of alveolar cells and their functions?
Type 1: thin; where gas exchange occurs
Type 2: secrete pulmonary surfactant; prevent fluid buildup in the alveoli
What are the components of the conducting zone?
trachea, primary bronchus (left and right), terminal bronchioles
What are the components of the respiratory zone?
respiratory bronchioles, alveolar sacs, alveoli
What’s the role of the respiratory zone?
responsible for gas exchange
What’s the role of the conducting zone?
sending air to the respiratory zone, as well as warming, humidifying, as well as mucociliary cleaning (mucus filters small particles and clears them by propelling mucus to the pharynx to be swallowed).
How does air enter the trachea?
passes through the glottis found between the folds of the larynx (vocal chords)
What’s the thoracic cavity?
cavity above the diaphragm
What’s the role of the parietal pleura and visceral pleura?
keep the lungs connected to the thoracic wall; they also produce a mucus-rich pleural fluid that fils the space between the two membranes (pleural space)
What’s a pneumothorax?
a collapsed lung; lung becomes disconnected from thoracic wall, resulting in a large intrapleural space.
What are the 3 physical properties of the lungs?
- compliance: must be distensible
- elasticity: must return to original size after being distended
- surface tension: fluid in alveoli act to collapse the alveolus due to bonds between water molecules, and increase the pressure of air within (law of laplace)
What is lung compliance?
change in lung volume per change in transpulmonary pressure (∆V / ∆P)
What is surfactant?
substance (mostly made of phospholipids) in alveolar fluid that reduces surface tension; it prevents H-bonds between water molecules (most effective during expiration)
What is Respiratory Distress Syndrome?
disorder common in premature newborns due to production of surfactant late in fetal development; babies struggle to get oxygen due to collapsed alveoli
What are the components of pulmonary ventillation?
inspiration and expiration
What muscles are essential for inspiration?
- sternocleidomastoid (laboured breathing only)
- scalenes (laboured breathing only)
- external intercostals
- parasternal intercostals
- diaphragm
What muscles are essential for expiration?
- internal intercostals
- abdominal muscles
What happens during inspiration?
- diaphragm lowers and flattens as it contracts
- external and parasternal intercostal muscles contract, raising the ribs and increasing thoracic volume
- sternocleidomastoid and scalenes elevate ribs in an anteroposterior direction, making intercostals more effective (in laboured breathing only)
> overall, intrapulmonary pressure decreases, causing air to flood into the lungs
What happens during expiration?
- internal intercostals contract to deepen the ribcage
- thorax and lungs recoil due to elastic tension
- abdominal muscles contract and force organs up against the diaphragm, further decreasing volume in the thorax
> overall, increase in intrapulmonary pressure, and air is pushed from the lungs
What are Pulmonary Function Tests?
recording breathing to create a spirogram in order to determine pulmonary function (done via spirometry)
What is Inspiration Capacity?
the maximum amount of gas that can be inspired after a normal tidal expiration
What is Inspiratory Reserve Volume?
the maximum amount of gas that can be inspired during forced breathing in addition to the tidal volume
What is Tidal Volume?
the amount of gas in an unforced respiratory cycle
What is Residual Volume?
the volume in the lungs after a maximum expiration
Why is there always at least some air in the lungs at any given time?
the alveoli and bronchioles do not collapse
What is Vital Capacity?
the maximum amount that can be expired after a maximum inspiration
What is Expiratory Reserve Volume?
the maximum volume of gas that can be expired during forced breathing in addition to the tidal volume
What is Functional Residual Capacity?
the amount of gas in the lungs after a normal tidal expiration
What is Total Lung Capacity?
the amount of gas in the lungs after a maximum inspiration
What is Total Minute Volume?
tidal volume x breaths per minute
What is Anatomical Dead Space
the volume of the conducting airways to the zone where gas exchange occurs (where O2 is low and CO2 is high)
> since this air enter the alveoli first, the fresh air per breath is actually less than the tidal volume
How do you calculate the amount of fresh air received in the lungs?
fresh air received = dead space / tidal volume x 100%
What is a Restrictive Disorder?
a disorder that causes the reduction of a person’s vital capacity
What is an Obstructive Disorder?
a disorder that causes the reduction of a person’s rate of respiration
How do you diagnose an Obstructive Disorder?
conduction of a forced expiratory volume (FEV) test – measures the percent of vital capacity exhales in the first second
What is Decompression Sickness?
when bubbles of N2 form in the tissue fluids and enter the blood stream (caused by scuba divers surfacing too fast; when surfacing slow, N2 diffuses through alveoli)
What is Oxygen Toxicity?
when oxidation of enzymes causes nervous system damage (caused by breathing high pressure O2)
What is Nitrogen Narcosis?
caused by large amounts of dissolved high pressure N2 in the body (resembled alcohol intoxication)
What is hemoglobin?
compound made of 4 polypeptide chains (globins) and 4 hemes; chemically bonds to O2
What is oxyhemoglobin?
an oxygenated hemoglobin
What is deoxyhemoglobin?
a deoxygenated hemoglobin
What is methemoglobin?
an oxidized hemoglobin; does not take part in oxygen transport
What is carboxyhemoglobin?
a hemoglobin bonded to a carbon monoxide molecule
What is Percent Oxyhemoglobin Saturation?
the ratio of oxyhemoglobin / all other hemoglobins
What happens during oxygen transport in the lungs?
- bicarbonate ion (HCO3-) spontaneous reacts with a proton to form carbonic acid (H2CO3), which is converted into CO2 and water by carbonic anhydrase
- CO2 floods into the alveoli from the blood plasma
- Flooding of CO2 results in an increase in pH
- O2 reacts to the increase in pH and floods into the red blood cell
What happens during oxygen transport in the tissues?
- CO2 floods from the cell and enter the blood plasma
- CO2 reacts with water in the plasma to form carbonic acid (H2CO3) by carbonic anhydrase, which spontaneously breaks into a bicarbonate ion (HCO3-) and a proton
- Flooding of CO2 results in a decrease in pH
- O2 reacts to the decrease in pH and floods into the cell from red blood cell
What is a Chloride Shift?
- Occurs during oxygen transport in the tissues
- CO2 and water are originally within the plasma, are are able to enter into the red blood due to active transport of the bicarbonate ion (HCO3-) into the red blood cell, and transport of a chloride ion (Cl-) out of the red blood cell
What is a Reverse Chloride Shift?
- Occurs during oxygen transport in the lungs
- Bicarbonate ion (HCO3-) is originally within the red blood cell, and exits into the plasma as a chloride ion (Cl-) is transported into the red blood cell
The thoracic cavity is lined with…
pleural membranes known as parietal pleura (lines thoracic wall) and visceral pleura (lines outside of lung)
