Class Notes (806,814)
Canada (492,451)
BIOL 1412 (89)

BIOL1412 01 22 2014.docx

4 Pages
Unlock Document

University of Manitoba
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 th
More Less

Related notes for BIOL 1412

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.