Temperature and thirst

Question 1

What is motivation?

Answer 1

An internal state that explains why we behave or why we learn to behave

Question 2

What is the drive reduction theory?

Answer 2

Proposed by Hull… a reinforcer supports learning because it alleviates an internal state of deprivation

Question 3

Homeostasis is a tendency by ____ systems towards ____/____

Answer 3

physiological equilibrium/balance

Question 4

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.

Answer 4

‘arousal’, action.
decrease
minimising, optimum, actual

Question 5

What are three physiological variables in the body that have optimum set points?

Answer 5

1. Temperature
2. Hydration
3. Nutrients

Question 6

Negative feedback is a process whereby the ____ produced by an ____ serves to ____ or ____ that ____.

Answer 6

effect
action
diminish
terminate
action

Question 7

What are the four components of a homeostatic “system”?
1. S____ V____
2. S____-p____
3. S____
4. E____ S____

Answer 7

1. System variable: variable controlled by system (e.g., temp, hydration, nutrients)
2. Set-point: the desired level of a variable
3. Sensor: a mechanism for measuring the variable
4. Effector system: behavioural /physiological mechanism(s) to change variable and restore homeostasis

Question 8

Sensors are cells in the Pre-____ area of the ____ that sense brain ____.
We have ____ sensors throughout our ____.

Answer 8

Cells in the Pre-Optic Area of the Hypothalamus sense brain temperature & we have thermal sensors throughout our periphery

Question 9

What does the hypothalamus control to regulate temperature?

Answer 9

Physiological and behavioural responses

Question 10

What are some bodily responses when we’re too cold?

Answer 10

Metabolism of brown fat
Increased thyroid activity
Shivering of muscles
Constriction of cutaneous blood vessels

Question 11

What are some bodily responses when we’re too hot?

Answer 11

Accelerated respiration
Perspiration
Dilation of cutaneous vessels

Question 12

Water comprises of what percentage of our lean body mass?

Answer 12

70%

Question 13

About ____ of water is inside cells, the remaining ____ is extracellular

Answer 13

2/3, 1/3

Question 14

Direct water loss occurs primarily from where?

Answer 14

Extracellular component

Question 15

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 ________

Answer 15

1. water, salts, sodium chloride
2. salts, increase
3. osmotic, extra, intra, leaves, osmosis

Question 16

Artificial increasing extracellular (NaCl) content stimulates what?

Answer 16

Drinking

Question 17

Drinking is directly proportional to a____ s____ l____

Answer 17

Additional salt load

Question 18

Microinjection of small amount of what into certain brain areas induces drinking?

Answer 18

NaCl

Question 19

Changes in osmolarity are monitored by cells (osmoreceptors) in the Or____num Va____sum of the La____na Te____lis

Answer 19

Organum Vasculosum of the Lamina Terminalis

Question 20

Loss of extracellular fluid (ECL) levels can induce thirst in the absence of o____ (salt) c____.

Answer 20

Osmotic (salt) changes

Question 21

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?

Answer 21

1. In the kidneys
2. In the heart
   Leads to drinking

Question 22

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)

Answer 22

1. renin, kidneys
2. angiotensinogen, angiotensin
3. pituitary, kidneys
4. vasoconstriction
5. binding, subfornical

Question 23

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

Answer 23

1. Atria, stretch
2. blood, veins
3. nucleus, solitary tract
4. median pre-optic