Class Notes (835,539)
Canada (509,225)
BIOL 1412 (89)

BIOL1412 01 22 2014.docx

4 Pages
Unlock Document

Biological Sciences
BIOL 1412
Paul Messing

BIOL1412 01 22 2014 Afferent NS (Fig. 13.2) 1) Stim. causes opening of gated channels (usually) Na+) on receptor membrane 2) GP on receptor membrane (stim. becomes electrical) IF: a) receptor = dendrite of unipolar cell & GP (depol.) directly generates anAP = a generator potential (Fig. 11.9) (but also called a receptor potential as it is a receptor) b) receptor = ind. cell eg. hair cell = receptor potential ⇒ nt into associated neuron ⇒ generator potential on neuron ⇒ generates anAP Types of Receptors: 1) Phasic Receptors - receptors respond to stim. change - in the presence of a constant stim. show adaptation (usually ⇓ in sensitivity) - eg. 1: put a hat on ⇒ burst ofAPs (feel it) ⇒ then get ⇓inAP even though stim. maintained at constant strength - eg. 2: Hat off - burst ofAPs - feel it again 2) Tonic Receptors - frequency ofAPs remain constant - NO adaptation - give con't-ous info. eg. posture, pain ⇒ protective - monitor presence + intensity of stim. How does brain perceive diff. types of stim.? - mainly by type of receptor stimulated - axon activated by receptor ⇒ stimulated connections to part of CNS concerned to brain (Fig. 13.2) - always know 'who' is calling (type of receptor) & from where (location)) eg. 1: stimulate Meissner's corpuscle (touch receptor) in right index finger (Fig. 13.2) & (Fig. 12.7) ⇒ impulses to postcentral gyrus region for right index finger eg. 2: mechanical pressure on eyeball ⇒ "seen" as light (Table 13.2) -ALL signals received from retina perceived as light How does brain perceive stim. of diff. strengths? eg. determining if feather or brick on foot? (Fig. 11.13) - mainly by frequency of APs (#/time) going to CNS eg. ⇑ stim. = ⇑AP frequency - strong stim. also activates more receptors (eg. pressure + touch) Sensory (ascending) Pathways: - 3 neurons in succession - 1st, 2nd & 3rd order (Fig. 13.2) - eg. Posterior (Dorsal) Column Pathways for touch: (Fig 12.31) association areas - memory, info from other areas identify - touch localized (back of hand) postcentral gyrus (general sensory area) ˅ AP EPSP 3rd (synapse in t
More Less

Related notes for BIOL 1412

Log In


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.