L3 Flashcards
the dynamic, self-regulating process of physiological and/or behavioural feedback control mechanisms to maintain a steady state within a living organism
homeostasis.
Homeostasis does not maintain ____ conditions, it restricts conditions within tightly regulated _____ ____ limits.
static, physiological tolerance
Homeostatic mechanisms can be _____ or ____.
physiological, behavioural
for a system to maintain homeostasis, it requires a ______ _____ (or set point) for the regulated variable, a ___ ___ to detect any deviation from this value, a ____ mechanism for the organism to make changes that return the variable to a normal range, a detection mechanisim to recognize the desired changes and shut down the mobilization process via a ____ _____ loop, and ____
reference value, detection mechansim, mobilization, negative feedback, energy
A stimulus causes a change in the variable, which causes an _____. A receptor detects this change, and information about it is sent along an _____ pathway. The ____ ___ compares the information against what value it is supposed to be. The instructions on a response are sent along an ______ pathway. The _____ produces a change in the variable that returns it to homeostasis
imbalance, afferent, control center, efferent, effector
In terms of fluid / electrolyte balance, ____ in the brain and body detect fluid imbalances. In the CNS, the ______ releases an _______ hormone (vasopressin), from the _____ _____ gland, which acts on the _____ to induce ___ ____ and generates the urge to drink fluids. In the PNS, the ________ system is activated, which causes -__ to be released from the adrenal glands and act on the kidneys to reabsorb both ___ and ___.
osmoreceptors, hypothalamus, posterior pituitary, kidneys, water retention, renin-angiotensin-aldosterone, aldosterone, water, salt
rabbits that live in areas with less sodium such as the ____, have high ____ concentrations and a greater percentage of the ____ ___ in comparison to rabbits with lots of access to sodium
mountains, aldosterone, adrenal cortex
_____ causes rats to drink saline water that they would normally not drink
adrenalectomy
Food is needed for 2 reasons: first we need it for ____ ____, which we get from amino acids, ____ and _____. This energy is needed to carry out all ___ ____, and is critical for _____ ____. It is also needed for ____ ___ for building structural parts of the body such as the bones, ____ and ___ _____
metabolic fuels, carbohydrates, fats, cellular processes, moment-to-moment, raw materials, muscles, chemical messengers
Proteins are needed to build ___ ___, which is used ini protein synthesis in the body
amino acids
complex carbohydrates are needed for ____, which is used for energy production in making _____ from ____
glucose, ATP, ADP
triglycerides are needed to make ____ and ___ ___, which is needed for ______ ____, and ____
glycerol, fatty acids, lipid synthesis, storage
Glucose can be stored as ____ via ______. When energy is needed, glycogen can be broken down back to glucose via _______. Glucose then undergoes _____ to create ATP
glycogen, glycogenesis, glycogenolysis, glycolysis
Hormone made by the pancreas that helps glucose get absorbed into the liver, fat, and skeletal muscle cells, which then will convert the glucose into glycogen
insulin
peptide hormone secreted from the pancreas that stimulates glucose production in the liver
glucagon
Food intake isn’t strictly under homeostatic regulation, but rather controlled in the ____ of homeostatic regulation. For example, feeding patterns and ____ ___ vary among individuals of the same species. Also, food intake relies on feeding, a behaviour that is under ____ ____, while other responses of homeostatic systems are _____.
interests, energy storage, conscious control, autonomic
In humans and many other animals, systems of energy balance appear to be _____. The system tolerates / permits _____ ____ ___ that lead to weight gain, but defends strongly against negative energy balances that threaten ____ ____. The body essentially doesn’t possess a clear _____ to sense positive energy balance. This is because energy is required for _____, and ___ favoured development of biological traits associated with an economical _____, as well as preferences for high energy-dense, energy ____ foods.
asymmetrical, positive energy balances, weight loss, mechanism, survival, evolution, metabolism, yielding
Eating is _____, and can often be dissociated from ___ ____ factors. Changes occur in response to food, but also during _____ of food intake. Social climate may also encourage individuals to intervene coercively in patterns of feeding behaviours that ____ their own biological processes
episodic, endogenous signalling, anticipation, endanger
there are a variety of signalling molecules involved in feeding that make it challenging to tease apart specific ___ of a signalling molecule in behaviour. ____ one hormone does not necessarily yield information on its function
roles, removing
insulin, which is released by the pancreatic ____ cells, _____ blood glucose. It is a ___ hormone, and stimulates glucose ___ by cells/ It also triggers ______ while inhibiting _____ and _____. Insulin receptors are expressed in virtually ____ cells
beta, decreases, peptide, uptake, glycogenesis, glycogenolysis, gluconeogenesis, all
Glucagon is a ___ hormone released from pancreatic _____ cells. Receptors for it are mainly expressed in the ____ and ____. Glucagon ____ blood glucose concentrations. Increases ______, and _____, while decreasing ___ ___ synthesis in ___ tissue and in the liver
peptide, alpha, liver, kidneys, increases, glycogenolysis, gluconeogenesis fatty acid, adipose
In a well fed state, food is broken down into ___, free ___ ____ and ___ ____. Glucose powers the ___ and ____. insulin is released from the pancreas to facilitate the ____ of glucose. The excess glucose is converted to ____ and stored in the ___ and ____.
glucose, fatty acids, amino acids, brain, muscles, transport, glycogen, liver, muscles
In a fasting state, ____ is released from the pancreas, which facilitates _____, to break down stores glycogen in the liver. _____ in adipose tissue releases the free fatty acids and _____. The liberated glucose and ___ bodies powers the brain
glucagon, glycogenolysis, lipolysis, glycerol, ketone
the paraventricular nucleus of the hypothalamus regulates ____ response and the _____, as well as _____ and ____ intake
stress, thyroid, osmoregulation, food
the lateral hypothalamus is involved in ___, ____ and ____
arousal, feeding, reward
the arcuate nucleus of the hypothalamus is involved in ____ balance, ____ and ___ ___ release
energy, reproduction, growth hormone
The AgRP/NPY neurons are cells of the ___ ___ that co-express ______ protein, and _____ __. They inhibit the ____ neurons of the PVN, and excite the _____ neurons of the ___.
arcuate nucleus, agouti-related, neuropeptide Y, anorexigenic, PVN, orexigenic, PFA
POMC/CART neurons of the ___ ____, are cells that co-express _______, and the ____ ____ _____ ____ ____ (CART). These ____ anorexigenic neurons in the PVN
arcuate nucleus, pre-opiomelanocortin, cocaine and amphetamine regulated transcript, excite
stimulation of ___. neurons with optogenetics induces eating in a rat
orexigenic
The arcuate nucleus is also modulated by hormones like ____ (pancreas) ____ (gut), and _____ (adipose tissue)
insulin, ghrelin, leptin
the gut-derived hormones indicate a _____ nutritional status. All of them also ____ food intake, in other words, serve as ____ signals. However, the exception is ____
short-term, reduce, satiety, ghrelin
Ghrelin is a _____ hormone, that peaks in blood concentration at the ___ of a meal. Systemic injections ______ food intake and increased ___ ___ in humans and rats. Ghrelin-releasing hormones send axons to the _____ and stimulate _____ /____ neurons in the ____ ____, enhancing their inhibition on ____ neurons in the PVN
peptide, onset, increase, body mass, hypothalamus, ArGP/NYP, arcuate nucleus, anorexigenic
adipose tissue hormones provide ____ information on nutrition status. They stimulate the ______ feeding circuit and inhibit the ____ feeding circuit, resulting in a net ____ of food intake.
long-term, inhibitory, stimulatory, decrease
a hormone protein released by adipose tissue; it serves as a satiety signal and starvation signal
leptin
leptin deficient (___/___) mice and leptin receptor deficient (____/___) mice are commonly used models of ___ and type ____ ___.
ob/ob, db/db. obesity, II diabetes
when fat is metabolized to provide _____, blood leptin ____ disproportionately more than fat levels, which provides a salient ______ signal
energy, decreases, starvation
active during the light
diurnal
nocturnal
active during the dark
virtually all ___, ___ and ___ processes show some circadian rhythmicity, which allows the organism to ____ with the environment so that energy is not expended to ___ against it
biological, physiological, behavioural, synchronize, fight
cue that an animal uses to synchronize with the environment
zeitgeber
Most of the time, rodents are active on their wheel in the ____. Reversing the light dark cycle will ____ the time the rats are on the wheel (___ ___). Putting the rats in continuous darkness will produce a ______ sleep/wake cycle. Similar results are shown for mice for a ____ cycle.
dark, reverse, phase shift, disorganized, drinking
synchronization / alignment of internal biological rhythms to the environment
entrainment
animals will exhibit sleep-wake _____ in the absence of any ____ cues. In other words, removing a ____ will still produce a _____ cycle period, but it may not be 24 hours in exact time.
pattern, external, zeitgeber, successive
large lesions of the ____ interfere with circadian rhythms, and produce a pattern similar to that seen with a ____ light.
hypothalamus, constant
lesions of the ______ ____ abolishes the circadian ____ without affecting the amount of sleep/wake/drink ____. In other words, there are ____ points of wake/sleep and no periods of them
suprachiasmatic nucleus, periodicity, bouts, random
When in light conditions, the ___ in the eyes detect light, and these cells release ____ onto neurons in the ____. ___% of the neurons of the SCN are light responsive. This will activate the transcription of ____ and _____. These proteins work in complex negative and positive gene regulatory loops to coordinate the ___ ____. The light induced activation of the SCN also prevents the production of ____ by the ____ gland
photoreceptors, glutamate, SCN, 30, PER1, PER2, circadian clock, melatonin, pineal
The SCN is also important for the modulation of ____ and ____
corticoids, testosterone
food can also be an entrainer of the _____ circadian rhythm. When food is abundant, the _____ cycle is the most important cue to entrain the _____ circadian rhythm. If food resources are ____, food becomes the most important cue. When food is normally given, glucocorticoid levels are highest at _____. When food is given only in the morning, glucocorticoids peak in the ___ instead. When food is given at a specific time in the evening, glucocorticoids are highest at that ____ ___.
glucocorticoid, light-dark corticosterone, scarce, night, morning, specific time
