Class Notes (808,753)
Canada (493,377)
BIOA02H3 (428)

BIO- MODULE 2- LEC 7.docx

2 Pages
Unlock Document

University of Toronto Scarborough
Biological Sciences
Mary Olaveson

Lecture 7 Cardio respiratory regulation Breathing is monitored by all the sensors. Peripheral chemoreceptor: sense change in o2 Central chemoreceptor—sense co2 levels/pH levels in spinal fluid. Stretch receptors in lunges—activate when expanded. Irritant receptors—irritant-coughing reflex. Positional receptors– in the joints and muscles that are activated during movement and exercise. In mammals, the motor output of the system goes to diaphragm by phrenic nerve Central brain controls breathing. Lot of important stuff here in pons and medulla. Human arterial oxygen chemoreceptors (Carotid body)—Type I (glomus) cells are the O2 sensors.---Low o2, activate O2 sensor, closes K+ channels, depolarizes the membrane, opens Ca++ channels, intercellular Ca rises, and triggers a neurotransmitter release. For amphibians, there is a diffuse structure called the carotid labyrinth. It serves the same oxygen sensing role as the mammalian carotid body. Only difference is that these cells are more diffusely organized. Fish atrial/water o2/co2 chemoreceptors—O2 and Co2 receptors in gill arches. Internal oriented chemoreceptors-blood sensing, externally oriented chemoreceptors, water sensing Cardiorespiratory responses to hypoxia in fish: When partial pressure of O2 in water is decreased, hypoxia sets in and the heart rate decreases Breathing frequency and breath amplitude increases. Hypoxia= decrease inspired O2. Central ph, Co2 receptors—in brain—Co2 diffuses through the capillary into the cerebral spinal fluid. The Co2 also combine with water to make carbonic acid, which creates h+ and this is sensed by the receptors, since due to the blood-brain dogma, the H+ does not pass through the walls. Stretch response in lungs.—stop inspiring when the lung gets full. Lungs inflate-PSR (pulmonary stretch receptors_ fire- input to brain NTS- terminates inspiration. Some have chemoreceptors in lungs instead of the stretch receptors. Have CO2 receptors. Animals such and turtles or snakes never stretch lungs, CO2 receptors work as stretch receptors. Blood enters lung with high co2 and
More Less

Related notes for BIOA02H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.