6.2 Chapter 38: Sensory Biology

chemoreceptors bind to particular ? in the ?, are used in the sense of ? and ?, also important in monitoring the chemical composition of ?

chemicals in the extracellular fluid (salvia, air); taste and smell; blood

taste (?): mixture of ? & ? factors, broken down into 5 categories ?, taste buds are collections of ? cells associated with ? neurons

gustation; physcial & psychological; sweet, sour, salty, bitter, umami (hearty); chemosensitive; afferent

in fish. taste buds are scattered all over the ? surface

body

in land vertebrates, taste buds are located in the ? within raised areas (?)

epithelium of the tongue & oral cavaity ; papillae

? & ? tastes act directly thru ion channels

salty & sour

other tastes act indirectly by binding to specific ?

G protein-coupled receptors

many ? also have taste chemoreceptors

arthropods

flies have chemoreceptors in sensory hairs located on their ?

feet (just get info don’t eat)

smell (?): in land vertebrates, involves neurons located in the upper portion of ?, recepetors project into ? & their ? project directly into the ?, particles must first dissolve in ? before they can activate the olfactory receptors, humans can detect ? of dif smells

olfaction; nasal passages; nasal mucosa; axons; cerebral cortex; extracellular fluid; 1000s

pH: peripheral chemoreceptors are found in ? bodies, sensitve primarily to the pH of ? & ? levels

aortic and carotid; plasma and PO2 & PCO2

pH: central chemoreceptors are found in ? of brain, senstive to pH of ?

medulla oblongata; cerebrospinal fluid

increase of CO2 in blood ? pH, which stimulates ?

decreases; respiratory control center

vision: begins with capture of light energy by ?, invertebrates have simple visual systems with photoreceptors clustered in an ?; flatworms can perceive the direction of light but cannot construct a ?, humans have ? types of photoreceptors

photoreceptors; eyespot; visual image; 3