The respiratory system part 5
Home > Flashcards > Print Preview
The flashcards below were created by user
on FreezingBlue Flashcards
. What would you like to do?
oxygen-hemoglobin dissociation curve
illustrates the relationship between the percent saturation of hemoglobin and P O2. In pulmonary capillaries where P o2 is high a lot of O2 binds to hemoglobin. In tissue capillaries where P o2 is lower, hemoglobin does not hold as much o2 and the dissolved o2 is unloaded via diffusion into tissue cells
as this rises the affinity of hemoglobin for O2 decreases and 02 disassociates more readily from hemoglobin
partial pressure of Co2
co2 can also bind to hemoglobin and the affect is similar to H+
as it increases so does the amount of O2 released from hemoglobin
carbon dioxide transport
under normal resting conditions each 100ml of deoxygenated blood contains the equivalent of 53ml of co2 which is transported in the blood
23% of CO2 combines with amino acids and proteins in the blood to form these.
70% of carbon dioxide is transported in blood plasma as this. As CO2 diffuses into systemic capillaries and enters red blood cells, it reacts with water to form this
clusters of neurons located bilaterally in the medulla oblongata and pons of the brain stem send nerve impulses to the respiratory muscles. It can be divided into 3 areas on the basis of their functions.
medullary rhythmicity area
controls the basic rhythm of respiration. There are inspiratory and expiratory areas within this area
establishes the basic rhythm for breathing. Well it is active it generates nerve impulses for 2 seconds the impulses propagate to the external intercostal muscles via external intercostal nerves and to the diaphragm via the phrenic nerve. after 2 seconds muscles relax
the neurons in this area remain inactive during quiet breathing. During forceful breathing nerve impulses from the inspiratory area activate this area. contraction of muscles causes forceful exhalation
helps coordinate the transition from inhalation to exhalation, located in the upper pons which transmits inhibitory impulses to the inspiratory area. it helps turn off the inspiratory area before the lungs get too full. breathing rate is more active when this area is more active
part of the brain stem that coordinates the transition between inhalation and exhalation. Activate the inspiratory area to have longer inhalations. When the Pneumotaxic area is active it overrides signals from this area
chemoreceptor regulation of respiration
monitor CO2 O2 and H+ levels and provide input to the respiratory centre
located in the medulla oblongata in the CNS. They respond to changes in H+ or P co2 or both in the cerebral spinal fluid
are located in the aortic bodies, clusters of chemoreceptors located in the wall of the arch if the aorta and in the carotid bodies, which are oval nodules in the wall of the left and right carotid arteries. These receptors are part of the PNS and are sensitive to changes in the blood
if a slight increase in P co2 occurs in arterial blood this condition occurs. The central chemoreceptors are stimulated and respond vigorously to the resulting increase in H+ levels.
rapid and deep breathing, allows inhalation of more O2 and exhalation of more CO2 until P co2 and H+ are lowered to normal
it arterial P co2 is lower than 40mmHg the central and peripheral chemoreceptors are not stimulated, and stimulatory impulses are not sent to the inspiratory arch. As a result, the area sets its own moderate pace until CO2 accumulates and the P co2 rises to 40mmHg
proprioceptor stimulation of respiration
nerve impulses form the proprioceptors stimulate the inspiratory area. At the same time axon collatoral of upper motor neurons that originate in the primary motor cortex also feed excitatory impulses into the inspiratory area.
is mainly a protective mechanism for preventing excessive inflation of the lungs rather than a key component in the normal regulation of respiration. It uses baroreceptors which are stretch sensitive receptors that are located in the walls of bronchi and bronchioles
What would you like to do?
Home > Flashcards > Print Preview