Temperature and thirst Flashcards
What is motivation?
An internal state that explains why we behave or why we learn to behave
What is the drive reduction theory?
Proposed by Hull… a reinforcer supports learning because it alleviates an internal state of deprivation
Homeostasis is a tendency by ____ systems towards ____/____
physiological equilibrium/balance
How is the drive reduction theory related to homeostasis?
Imbalance in homeostasis creates ____ that initiates ____
The goal of homeostasis is to ____ the arousal.
Can achieve this goal by ____ the difference between an ____ set-point and ____ point of a physiological system.
‘arousal’, action.
decrease
minimising, optimum, actual
What are three physiological variables in the body that have optimum set points?
- Temperature
- Hydration
- Nutrients
Negative feedback is a process whereby the ____ produced by an ____ serves to ____ or ____ that ____.
effect
action
diminish
terminate
action
What are the four components of a homeostatic “system”?
1. S____ V____
2. S____-p____
3. S____
4. E____ S____
- System variable: variable controlled by system (e.g., temp, hydration, nutrients)
- Set-point: the desired level of a variable
- Sensor: a mechanism for measuring the variable
- Effector system: behavioural /physiological mechanism(s) to change variable and restore homeostasis
Sensors are cells in the Pre-____ area of the ____ that sense brain ____.
We have ____ sensors throughout our ____.
Cells in the Pre-Optic Area of the Hypothalamus sense brain temperature & we have thermal sensors throughout our periphery
What does the hypothalamus control to regulate temperature?
Physiological and behavioural responses
What are some bodily responses when we’re too cold?
Metabolism of brown fat
Increased thyroid activity
Shivering of muscles
Constriction of cutaneous blood vessels
What are some bodily responses when we’re too hot?
Accelerated respiration
Perspiration
Dilation of cutaneous vessels
Water comprises of what percentage of our lean body mass?
70%
About ____ of water is inside cells, the remaining ____ is extracellular
2/3, 1/3
Direct water loss occurs primarily from where?
Extracellular component
Fill in the gaps about osmometric thirst/cellular dehydration…
1. Extracellular fluid consists mainly of _______ and _______ (particularly _______ _________)
2. Water loss causes the concentration of ______ to ________
3. This increase in salt causes an ______ imbalance between the ______ and _______ cellular compartments, and water _______ cells to restore balance by ________
- water, salts, sodium chloride
- salts, increase
- osmotic, extra, intra, leaves, osmosis
Artificial increasing extracellular (NaCl) content stimulates what?
Drinking
Drinking is directly proportional to a____ s____ l____
Additional salt load
Microinjection of small amount of what into certain brain areas induces drinking?
NaCl
Changes in osmolarity are monitored by cells (osmoreceptors) in the Or____num Va____sum of the La____na Te____lis
Organum Vasculosum of the Lamina Terminalis
Loss of extracellular fluid (ECL) levels can induce thirst in the absence of o____ (salt) c____.
Osmotic (salt) changes
The thirst stimulus arises from two systems which measure blood pressure. Where are these systems?
This combined information stimulates brain sites which leads to what?
- In the kidneys
- In the heart
Leads to drinking
Fill in the gaps about angiotensin and drinking?
1. Hypovolemia causes the release of the enzyme r_____ from the k______
2. Renin converts a blood-borne molecule (a__________) into a_________
3. Angiotensin stimulates p_______ and k________ to release hormone to conserve water and salt
4. Increase blood pressure by v_________
5. Stimulates drinking by b_______ on receptors ion the s_______ organ (SFO)
- renin, kidneys
- angiotensinogen, angiotensin
- pituitary, kidneys
- vasoconstriction
- binding, subfornical
Fill in the gaps about atrial baroreceptor…
1. ____ of heart contain neurons that detect ______ (baroreceptors)
2. Volume of return ______ through _____ detected by baroreceptors
3. Information from baroreceptors to _____ of the _____ _____
4. Information to _____ ___-___ area
- Atria, stretch
- blood, veins
- nucleus, solitary tract
- median pre-optic
