Homeostasis Flashcards
What happens when the parasympathetic division is activated in initiating feeding?
Feeding behavior is stimulated
What does drinking more water cause in hyponatremia?
Worse conditions. Fave the fluid signal (ADH) mixed with more fluid
A fluid containing solutes
Solution
What is lipostatic theory and where can it be seen functioning in the body?
We are sensitive to the amount of fats we have. Receptors in the liver monitor fatty acids
What does the ventromedial hypothalamus do?
Participates in satiety (fullness)
Why do we eat?
Energy and nutrients, pleasure, and complex cultural and psychological factors
How is hyponatremia caused?
Extreme endurance activities caused by low extracellular fluid and low Na
What are osmoreceptors?
Neurons that change firing rate due to water tonicity
What parts of the brain are associated with the hypothalamus?
Infundibulum, anterior pituitary, and posterior pituitary
What does angiotensin II do?
Aids in maintaining blood pressure (tightens blood vessels) and signals the adrenal glands to secrete aldosterone which promotes retention of sodium by the kidneys
Solutions with equal concentrations of solutes. Goal
Isotonic
What leads to hydration?
Water + electrolytes
What percentage of body fluid is intracellular?
67%
What happens with ADH and Na levels in hyponatremia?
ADH is continuously produced which causes water retention and further reduction in Na concentration
What are causes of hypovolemic thirst?
Sweating, vomiting, diarrhea, and blood loss (this is why a cookie and juice is given after blood donations)
Contains warm sensitive (30%), cold sensitive (5%), and other neurons (65%)
Preoptic area of the anterior hypothalamus
What is sensory specific satiety?
When we reject food that’s too similar to what we’ve been having. We want variety
Thirst that is caused by eating. The consumption of liquids while eating
Prandial thirst
Part of the brain that detects and responds to cooler temps. Shows more neuronal activity when the blood is colder
Posterior hypothalamus
How is hyponatremia prevented?
Taking in electrolytes during and before extreme endurance activities. Consumption of salty snacks before/during endurance activities
What are prostaglandins?
A product of the hypothalamus that raises our temp set point
What are the mechanisms of hypovolemic thirst?
Results from lower volume of interstitial fluid, blood, or both.
Lower blood volume is sensed by receptors in the heart and kidneys
The wall of the heart muscle contains baroreceptors that measure blood pressure
As blood volume decreases, blood pressure decreases as well
The kidneys contain blood flow receptors that also respond to changes in blood volume
What does hyponatremia cause?
Hypovolemic thirst, cell swelling, severe headache
How is food regulated?
Ebb and flow of nutrient absorption and use (diff patterns in burning energy), short term and long term energy needs (save energy for use later), and body weight set point
Disorder of insulin production diagnosed in childhood or early adulthood
Type 1 diabetes mellitus
What does a lesion to the OVLT cause?
Reduced drinking in response to salty solution
What do kidneys secrete in hypovolemic thirst?
Renin
What are the endothermic responses to warm temps?
Perspiration (human default), licking and panting (other animals), and blood vessels dilate near skin surface
What does a constant need for energy with feeding occurring intermittently show?
We have to function in low and high caloric settings
Signals that encourage food consumption
hunger/appetite
How should weight loss be approached and why?
Small gradual changes are more impactful than extreme changes due to set point. Your body could think you’re starving with large changes
What are the areas of the brain associated with satiety?
Ventromedial hypothalamus, paraventricular nucleus, and nucleus of he solitary tract
What do antidepressants and serotonin syndrome cause?
GI distress, high fever, hallucinations, and possibly death. Very rare
What happens to urine production in hypovolemic thirst?
It is reduced to conserve fluid
Solutions with a higher concentration of solutes outside the cell
Hypertonic (shrivels)
What are upper value, lower value and set point?
Upper: triggers a response to counteract the increase
Lower: triggers a response to counteract the decrease
Set point: ideal value
Whats the chemical signal to retain sodium?
Aldosterone
Levels of ghrelin and leptin in hunger and satiety
Hunger: leptin low and ghrelin high
Satiety: leptin high and ghrelin low
A complex carbohydrate used to store energy in the liver. Long term energy storage
Glycogen
What does the Zona Incerta do? Where is it?
Initiates drinking. If it is stimulated, the animal will drink no matter what. Located outside the hypothalamus
What are cytokines?
Inflammatory markers released by leukocytes
How does a fever work?
In response to reduced inhibition from the warm sensitive neurons, cold sensitive cells increase their output which results in a higher temperature set point
What do low leptin and insulin levels stimulate the release of?
Neuropeptide Y (NPY) and agouti-related protein (AgRP) from the arcuate nucleus
Thirst that is a response to low fluid level in the bodys cells due to diffusion
Osmotic thirst
What is the path temperature detection takes in the body?
Structural hierarchy from thermoreceptors to spinal cord through the brainstem to the hypothalamus
Three things in the body for assessing satiety
Stomach fullness, duodenal glucoreceptors, and cholecystokinin
Activates and directs behavior toward a goal. Imbalance in a state causes this. Has drive/push theories and incentive/pull theories
Motivation
What does the lateral hypothalamus do?
Participates in hunger
Disorder of insulin recognition by cells. Has an adult onset and obesity is a major risk factor
Type 2 diabetes mellitus
What happens to TSH and ACTH release in eating initiation?
Release is suppressed to slow metabolism
A pancreatic hormone that assists in moving glucose from the blood supply into body cells. Helps store glucose as glycogen
Insulin
Used for immediate energy, stored by adipose tissue, and causes release of hormone cholecystokinin (CCK) which is a satiety signal
Lipid/fat digestion
What is learned taste aversion?
Association of food with illness or poor nutrition
Sensory info from baroreceptors and osmoreceptors via vagus nerve
nucleus of the solitary tract
Signals that end food consumption
satiety