Class Notes (834,816)
Canada (508,735)
BIOL 1412 (89)

BIOL1412 01 08 2014.docx

3 Pages
Unlock Document

Biological Sciences
BIOL 1412
Paul Messing

BIOL1412 01 08 2014 Homeostatic Regulation a) Negative Feedback - Most common homeostatic control mechanism - Result of "output" - variable moves back toward the set point ie. in opposite (neg.) direction to the change that triggered the response ("input") - eg. body temp. ( = variable) set point 36 to 37.8° C If ⇑ temp. (eg. 40° C) "input" "output" hypothalamus ⇒ Brain ⇒ E=smooth thermostat muscle of cells (r) blood vessels detect high in skin relax temp. (stimulus) (causing dilation) + sweat glands secrete sweat - Result = core blood to skin surface and sweat evaporates = ⇑ heat loss and ⇓ temp. (opposite direction of input) eg. 2 ⇓ temp. ⇒ shiver ⇒ ⇑ temp. - set point can change eg. fever = cause by bacterium b) Positive Feedback - less common - NOT homeostatic - output intensifies the input (enhances it) eg. childbirth - labour * uterine contractions ⇓ +ve feedback = NS ⇑ contractions ⇓ posterior pituitary gland ⇓ releases oxytocin (hormone) - *con'ts until endpoint ( = baby born) Topic 2: Cell Physiology I The Cell Membrane (Fig.3.3) 1) Phospholipid Bilayer - con't-ous layer around the cell - barrier to H2O soluble substances - NOT to small mol.s (O2 & CO2) & lipid soluble mol.s 2) Membrane Proteins a) Transport Proteins
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.