Respiratory System Flashcards
What are spiracles in insects?
Opening of the trachea; contain closing mechanisms; some aquatic insects; gas exchange happens because array of trachea close to thin cuticle
How is oxygen transported in the circulatory system?
Bound reversible to hemoglobin
How is CO2 transported?
Mostly transported as bicarbonate ion in the plasma
Why does O2 need to be paired with hemoglobin?
Oxygen is very insoluble in plasma and you can only transport very little per 100 mL; Hb is needed to transport enough O2
How does O2 diffuse into body cells?
Po2 is higher in plasma than interstitial fluid so it diffuses into ISF and then in body cells
How does CO2 transfer through the body?
Pco2 is higher in tissues so it converts into H+ and HCO3- (in the cells) or combines with hemoglobin (and is slightly dissolved in plasma) to be transported to the lungs and exhaled
What is the trachea in insects?
Internal tubes, with finer branches extended to all parts of the body and may become functionally intracellular in muscles
What is the central controlling of breathing?
The brainstem
How is breathing controlled
Neurons myogenically fire APs which generates rhythm controlling the frequency, depth, and amplitude of breathing;
breathing is intiated by an inspiratory neuron; contraction of diaphragm and intercostal muscles (intercoastal motor neurons) causing the lungs to inflate; this activates stretch receptors and therefore inactivates the inspiratory neurons to stop inspiration (Hering-Breuer reflex); during exercise–>expiratory neurons control this reflex
the cortex also offers voluntary control and this system is modified by inputs from the brain and peripheral receptors
What are the peripheral chemoreceptors and what do they do?
They are carotid and aortic bodies ; they sense mostly O2 in the arteries
What do central chemoreceptors do?
sense CO2 in the cerebrospinal fluid
What are all of the lung receptors, and what do they do?
Stretch receptors–>hering-breuer inflation reflex
Irritant, pain, and temp receptors–>initiate coughing
Juxtacapillary receptors–>engorgement of capillaries–>dyspnea (sensation of difficulty breathing)
What receptors are needed in high-altitude animals?
The chemoreceptor aortic bodies
What happens if someone lacks carotid bodies?
When oxygen levels decrease, there are no carotid bodies to increase ventilation rate so you do not realize you are in an environment with low O2; but what drives out ventilation rates most is CO2 not O2
What is the major ventilation rate controls in aquatic animals?
LEvels of O2; it is less soluble in water; if ventilation is adequate for O2 is must be adequate for CO2 as well; O2 conc in variable in water depending on temp; under most conditions ventilation does not limit CO2 excretion in aquatic animals
