NEURO 3 (8) sec 1

homeostasis

process by which the body achieves a
stable, balanced internal environment

set points

optimal points at which a given physiological system functions best

set zone

range within which physiological system can function

within set zone what will always try to return the system to the set point

homeostasis

negative feedback loop

homeostasis counteracts deviation of set point by doing the opposite in order to get to set point again

thermoregulation

process by which the body maintains an ideal temperature

for mammals body temp is maintained by?

utilizing heat produced thru metabolism

thermoregulation is also partly?

behavioral

reptiles have low metabolisms thus _____ thus they are more reliant of behavioral measure of thermoregulation (tend not to live in colder environment)

produce less heat internally

where are temp receptors throughout your body

externally (skin surface)

internally (including brain itself)

preoptic area (POA)

the hypothalamus takes care of the physiological responses that raise body temp in response to cold

shivering

heat generated through metabolic burn required for motion

Constriction of Blood Vessels

body’s exterior: Reduced blood flow
makes skin and fat more effective as
insulation

what is the area that is in contrast to the POA aka preoptic area

lateral hypothalamus

what is the lateral hypothalamus crucial for?

behavioral regulation of
temperature

often reptiles will choose ___ over food because of the lateral hypothalamus

heat

what are the two forms of thirst

osmotic and hypovolemic

osmotic thirst is when you body is filled with? which makes your fluid levels drop

salt water

how is osmotic thirst triggered

upswing in salt levelsin the blood, prompting the hypothalamus to signal thirst.

hypovolemic thirst is a ___ in the volume of bodily fluids such as blood which is mostly water

decrease

hypovolemic thirst is caused by

triggered even if salt concentrations do not change (bleeding etc)

what organs contain osmosensory neurons

circumventricular organs

osmosensory neurons detect what

the changes off concentration of salt in your body

osmosis

diffusion of solvent molecules across permeable biological membrane Na and Cl are more regulated

what does shrinking of cells cause by opening up mechanically gated ion channels in the membranes of osmosensory neurons

its causes a genorator potential that makes the osmosensory neuron more likely to fire and action potential

hypovolemic thirst is made possible by

baroreceptors

both hypovolemic and osmotic thirst require what region

POA

signals detected by both osmosenory and baroreceptors reach the ___ an activate it causing increased drinking behavior

POA

what does the POA also trigger besides thirst

the release of vasopressin from the pt gland (retaining water)

what are the essential nutrients

glucose; certain vitamins and minerals; some fatty acids (omega-3)

glucose

primary sugar used by body for energy

when glucose rises

insulin also glucose to enter muscles and liver cells to be converted into glycogen

glycogen is a ____-term storage

short

when glucose levels fall

glycogen is converted back into glucose by glucagon

for long term storage of glucose it is stored where

adipose tissue

where does insulin bind to when you eat

a receptor on the surface of muscle and liver cells

the majority of energy is spent on??

BMR: which goes to heat production, maintenance of ion gradients especially in the brain: lifesustaining cellular processes

when you bmr decreases your energy intake ____: which is called ____ adaptation

decreases; metabolic

when metabolic adaptation takes place specifically an increase

increases in basal metabolism in
responses to increases in energy intake
do not tend to occur as rapidly, or to the
same degree

arcuate nucleus

monitors levels of various hunger and satiety hormones which can activate two different neurons (POMC and NPY)

POMC neurons signal what

saiety

NPY neurons signal what

hunger

ghrelin

ghrelin levels drop after eating and high levels activate NPY neurons

Insulin

released from pancreas in response to food

High insulin levels _____ NPY neurons which ____ hunger; POMC neurons become ____ thus ____ satiety

inhibit, decrease

uninhibited, increasing

leptin

released from fat cellst

the amount of circulating leptin is ___ to body fat levels

PROPORTIONAL

High leptin inhibits what

NPY neurons and activates POMC neurons

Glucagon-like peptide 1 (GLP-1):

released
from digestive organs in the presence of food
in the gut. GLP-1 stimulate insulin release
from pancreas and activates POMC neurons

Semaglutide

GLP-1 receptor agonist.
Marketed under the trade name Ozempic, it
is a treatment for Type-II diabetes
administered as a once-weekly injection. It is
also being used as a weight-loss drug. It
reduces appetite directly (by activating
POMC neurons) and indirectly (via the effect
of insulin on NPY cells)

human beings will eat beyond our homeostatic needs
simply because it’s _____

pleasurable

energy intake is also regulated by???

hedonic mechanisms

_____
eating motivates us to take advantage of scarce, vital
resources (such as high calorie foods) whenever we have the
opportunity to do so

HEDONIC

NAcc

part of the basial ganglia which neurons express the mu-opioid receptor

Injection of mu-opioid receptor agonist DAMGO

causes rats to consume more sugar water
even if the rat is neither hungry nor thirsty.

Refined and processed foods are engineered to
achieve a______ , the amount of an ingredient
needed to maximize food consumption.

BLISS POINT

These foods
tend to be among the cheapest available

bliss point

Sensory Specific Satiety

the more
you eat of a specific food, the less you will want
it. However, even if you are full, you may still be
willing to consume a good amount of a very
different food.

The ____ is a key player in both the physiological and
behavioral responses necessary to maintain homeostasis

hypothalamus

Energy intake is controlled by both ___ and ___
mechanisms

hedonic

homeostatic