Chemoreceptors

Sensory Transduction

converting an external stimulus to a biological signal/AP

Sensory systems purpose

detect potential danger, find food, navigate environment

Importance of studying sensory physiology

helps us understand how organisms interact and adapt to changing environments

Specialized receptor cell function

detect different types of stimuli, detect and transmit information

Chemoreceptors

detect chemicals

photoreceptors

detect light

Thermoreceptors

detect temperature

Mechanoreceptors

detect pressure and touch

Nociceptors

detect pain

proprioceptors

detect limb and body position

Chemoreceptor path

detect change in environment, alert CNS, respond to restore homeostasis

Internal peripheral chemoreceptors

sensory extensions of PNS in blood vessels to detect chemical changes

Chemicals interacting directly with neuron

will generate an action potential

Chemicals interacting with non-neuron

will cause NT release to bind/activate nerve fiber, which later generates AP

Distance Chemoreceptors

not directly interacting with the substance’s origin

Olfactory chemoreceptors location

in olfactory epithelium

Olfactory transduction

odor molecules bind to cilia → AP → nerve filaments → olfactory bulb(neurons) → olfactory tracts

Direct Chemoreceptors

direct interaction with souce of chemicals

Tastebuds

a collection of chemoreceptors in elongated pore of taste cells

Taste concentration

more concentration = more AP = stronger stimulus

Taste adaptation

relatively slow, re-taste with each bite since saliva washing away taste constantly

Peripheral Chemoreceptors

carotid and aortic bodies

Carotid bodies

sense partial pressures and pH

Aortic bodies

sense CO2 and O2 concentrations

Central chemoreceptors location

on ventral medulla

Central chemoreceptors function

sense pH in CSF (driven by CO2)

Central & Peripheral chemoreceptors afferent site (go to)

respiratory center of medulla

Dorsal Respiratory Group

for inspiration under normal, non-forced conditions

Ventral Respiratory Group

stimulate DRG when additional, non-normal need arises

Pneumotaxic center

turns off DRG for passive respiration

Cardiac center location

medulla oblongata

Baroreceptors

located in major vessels, detects decreased O2 and pH, or increased CO2

Cardiac center normal function

baroreceptors detect changes, cardiac center processes, nerve signals to change heart rate