PSYB64H3 Lecture Notes - Lecture 6: Vascular Organ Of Lamina Terminalis, Vasopressin, Lamina Terminalis

29 views10 pages
Published on 14 Nov 2012
School
Department
Course
PSYB64 Lecture 6 “Temperature, Regulation, Thirst, and Hunger”
1. Homeostasis
2. Temperature
3. Thirst
4. Hunger
5. Obesity & Hunger Disorders
HOMEOSTASIS
Homeostasis: Physiological equilibrium
Motivation: Activating and directing behavior
Regulation of Body Temperature
Set point
Mechanisms for detecting deviation
Internal and behavioral elements to regain set point
Adaptations to Temperature
Endotherms
maintain constant body temp.
Ectotherms
body temp. same as environment = amphibians, reptiles and most fish
Surface-to-Volume Ratios Affect Temperature Regulation
The higher an animal’s surface to volume ratio the harder it must work to
maintain core temperature
Small animals have larger surface to volume ratios hence maintaining core
temperature is harder for them than for larger animals? Who works harder
to maintain this ratio, the rat of the human?
Behavioral Responses to Heat and Cold
Ectotherms more dependent on behavioral devices
Changes in position, weight, color and composition of fur
Endothermic Responses to Heat and Cold
Automatic internal response to deviations in temperature
Responses to lower temperatures
Shiver
Blood vessels constrict
Thyroid hormone increase
Responses to lower temperatures
Perspiration, licking
Blood vessels dilate
Deviations in Human Core Temperature
Fever
Heat stroke (hyperthermia)
Hypothermia
Emergency Hypothermia video clip
http://www.youtube.com/watch?v=vc86u0IsOwc
Brain Mechanisms for Temperature Regulation
See Fig 9.7
Temperature Regulation in Infancy
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in
Relatively helpless in adapting to temperature
HYPOTHALAMUS CONTROLS TEMPERATURE REGULATION
THIRST: REGULATION OF THE BODY’S FLUID
Intracellular and Extracellular Fluids
Extracellular fluid (33%)
Intracellular fluid (67%)
Osmosis Causes Water to Move
Water moves from an area with lower concentration of solutes to an area with
higher concentration
Hypotonic versus hypertonic
The Role of the Kidneys
Excretes excess fluids and sodium
THE BODY’S FLUIDS ARE HELD IN THREE COMPARTMENTS
Osmosis Causes Water to Move
SOURCES OF TYPICAL DAILY FLUID LOSS AND INTAKE IN HUMANS
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in
THIRST: REGULATION OF THE BODY’S FLUID
The Sensation of Thirst
Occurs as a result of osmotic (drops in the intracellular fluid volume) and
hypovolemic (drops in blood volume) thirst
Can you think of examples of when these may occur?
Mechanisms of Osmotic Thirst
Osmoreceptors located in the brain
Organum vasculosum of the lamina terminalis (OVLT)
Mechanisms of Hypovolemic Thirst
Baroreceptors measure blood pressure
Receptors in the heart and kidneys
Detecting Osmotic Thirst
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.