Motivation

Motivation

The shifting of attention, why you change behavior

Homeostasis

The maintenance of body resources at a setpoint

who discovered homeostasis

walter cannon

3 systems of homeostasis

1. temperature

2. water

3. hunger

when temp _______, there is _______ biochemical reaction rates

increase

faster

Q10

measure of enzymatic activity that states the biochemical reactions in a cell or any system is what happens to them when you go 10 degree F up or down

do cells work dependently or independently

dependently

why is it important to keep temp constant

reactions can become uncoupled in your cell if it goes faster/slower

conduction

• direct contact between solid surfaces

convection

movement of heats between fluids

radiation / electromagnetic radiation

radiant energy hitting you from the front but not the back

2 changes of state and what are they

condensation - net gaining heat

evaporation - net losing heat

2 types of animals Thermoregulation

1. homeotherms

2. poikilotherms

What are homeotherms

when you put them in a warm or cold enviornment, their body temp doesn’t change very much

poikilotherms

body temp vary depending on environment - hot/cold blooded animals

how do homeotherms cope with temp changes if cold

1. decrease conduction - fur hat feathers

2. increase production - metabolic heat - temporary

3. migrate

4. hibernate

how do homeotherms cope with temp changes if hot

1. avoid it

2. fur, feathers to reflect light

3. evaporative heat loss → sweat, lick body

where is the hypothalamus located

in the diencephalon

medial preoptic

responsible for balance behavior

Double disassocation experiment

1. insert end of probe(can control temp) into animals hypothalamus

2. cold animal - insert hot probe into preoptic area

3. animal shows behavior as if its warm

this shows that the medial preoptic can ……

monitor body temp and initiate physiological responses that allow you to cope with that temp

3 places water is found in

1. your cells / intracellular spaces which has the most water

2. extracellular space - space between cells

3. blood plasma

what is the pathway when you drink water

drink water → stomach → intestine → blood plasma → extracellular space → intracellular space

when you lose water you’re losing it from _____

plasma

water flow ______ , while solutes _________

changes

stay the same

osmosis

the movement of water

tenicity

amount of stuff per unit of water

isotonic

external environment that has the same concentration of solutes (salts, sugars) as the inside of a cell

• correct amount of water per stuff in comparments, where we can efficinetly function

hypotonic

drinking water - does not have solutes

hypertonic

eating something salty - more solutes

in a hypertonic solution there is ________ (lower/higher) concentration of water in the __________ (space) rather than in _______(space)

lower

intracellular

plasma

high blood pressure means you have a

high salt diet

lateral preoptic area of hypothalamus is responsible for

• responsible for sensing whether or not we have enough water in our system

hypovelemic response

blood volume decreases

high blood volume → vessels are _____

stretched/taut

low blood volume → vesels are _____

loose

blood volume affects

1. pressure against vessel walls

2. overall blood pressure

baroreceptors - where located, function

1. located in blood vessels

2. function: detect stretch/blood pressure

process of hormonal response to low blood volume

1. decreased stretch detected from baroreceptors

2. signals trigger the kidney to relase renin (hormone)

3. renin travels through the blood

4. renin acts on a target in the blood → angiotensin

5. angiotensin levels increase

6. angiotensin acts on the brain

subfornical organ / SFO

detects angiotensin in the blood

3 steps after angiotensin actives SFO

1. SFO activates the hypothalamus

2. hypothalamus signals pituitary gland

3. releases vasopressin

3 vassopressin functions

increases blood pressure by the constriction of blood vessels

conserves water / less urine

triggers thirst

satiety

stopping eating

digestive system process

mouth → stomach →small intestine → duodenum → large intestine

chewing ________ surface area of food

increases

chewing helps __________ proteins and sugars. ______ help do this

break down

enzymes

food travels down the ________.

esophagus

sphincter is a muscle which

acts as a gate to the stomach

stomach

large reservoir to contain food

adds hydrochloric acid and other enzymes to break things down

has a machine that churns to digest

the small intestine contains another _________.

sphincter to open/close entrance from stomach to intestine

the small intestine transports nutrients out of the ____________ _________ and back into the __________.

digestive system

blood

then the nutrients are taken out of the blood and put into the ______ space and then to the _________ space.

extracellular

intracellular

duodenum is where ….. it also controls whether…

where the sphincter muscle comes down from the stomach and connects to the small intestine

the stomach is still sending food to the small intestine or not

large intestine

collects everything you haven’t digested, waste

two cues for satiety

oral and stomach

oral cues

non palatable things that down taste good wont be eaten much

stomach cues

stomach measures stretch , so more stretch = full

stomach sends cues to what two nerves

vagus, splanchnic

these nerves are imporant to

detect stretch

pathway to detect satiety

stomach → duodenum → stretches duodenum → signal back to sphincter to close it up

the signal is…..

cholecytokinin - cck

cholecytokinin is released by _______

duodum

leptin is ______ tissue. it is a ….

adipose/fat tissue

long term food storage

more fat = _____ leptin secreted

more

no leptin receptors = secret too much leptin would result in

obesity

ghrelin is the ______ signal.

hunger

increased levels of ghrelin means …..

decreased levels of ghrelin means …..

eat

full

prader willis syndrome is ______________

high ghrelin levels

hypothalamic pathways lesions studies - lateral hypothalamus

• skinny

• akinetic animals would starve to death if not fed

ventral medial hypothalmus

• fat

• issue with insulin

• medial forebrain bundle lesions would destory many axons

what 2 things excite hunger

1. ghrelin

2. taste

3 things inhibits hunger

leptin, cck, insulin

the hunger pathway is __________.

inhibitory

neurons release these 3 neurotrasmitters at once in the hunger pathway:

NPY

AgRP

GABA

hunger pathway function

inhbitory → supress satiety signals → increase hunger

the satiety pathway is _____

excitatory

satiety pathway function

excitatory → promote satiety → reduce hunger

the satiety pathway releases

melanocortin

an agonist will ___ neurotransmitter effect.

_____ melanocortin and ____ sateity

increase increase increase

antagonist will ______ neurotransmitter effect.

____ melanocortin and ______ satiety

block

decrease

decrease

Amygdala

group of nuclei located in the temporal lobe

amygdala brings ____ info into this motivation pathway

sensory

amygdala is part of the __________ ___________.

basal ganglia

how many nuclei associated with the amygdala

22

sensory info goes to the _________ area of the amygdala

basolateral

basolateral

bottom and outside area

centromedial

in middle

two ways the amygdala processes all info coming in

1. behavioral response

2. autonomic and hormonal responses

The behavioral response interacts with

ventral striatum and dorsal medial thalamus

the autonomic and hormonal responses interact with

hypothalamus, midbrain, pons, medulla ,basal forebrain

sensory info to travel around in cortex is ______ while amygdala response is __ ( slow or fast )

slow

fast

why is the amygdala response so fast

amygdala is prescreening info and allows you to make decisions in a quick way before going to higher level processing

reward

when an animal approaches a stimulus with a positive outcome and stays/goes to it and avoids negatively rewarding situations.

Jim Olds and his experiment

tried to teach mice to press button in a cage

accidentally put electrode close to the nucleus accumbens

when they pressed the button, it was pleasurable for them

reward center is in the

nucleus accumbens

the substantia nigra contains __________ neurons that project axons to the ____________.

dopaminergic

basal ganglia

another way that dopamine allows us to make decisions…. what is this area called

ventral tegmental area - VTA

VTA

projects to a lot of different places that receive domapminergic input

mesostriatal pathway what it is and function

substantia nigra → striatum (caudate putamen) for movement and motor planning

mesocortical system

VTA → frontal cortex to regulate emotions or planning