Chapter 13: Homeostasis, Active Regulation of the Internal Environment
Aldosterone
"salt-retaining hormone" which promotes the retention of Na+ by the kidneys. na+ retention promotes water retention, which promotes a higher blood volume and pressure
obesity treatments (7)
1. epigenetic transmission 2. apetite control 3. increased metabolism 4. inhibit fat tissue 5. reduced absorption 6. reduced reward 7. anti-obesity surgery
leptin
A hormone produced by adipose (fat) cells that acts as a satiety factor in regulating appetite.
Atrial natriuretic peptide (ANP)
A hormone, secreted by the heart, that normally reduces blood pressure, inhibits drinking, and promotes the excretion of water and salt at the kidneys.
ghrelin
A hunger-arousing hormone secreted by an empty stomach
hypothalamus
A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.
negative feedback
A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation.
subfornical organ
A small organ located in the confluence of the lateral ventricles, attached to the underside of the fornix; contains neurons that detect the presence of angiotensin in the blood and excite neural circuits that initiate drinking.
homeostasis
A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level
aquaporins
A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane
ectotherms
An animals that warms itself mainly by absorbing heat from its surroundings
endocannabinoid
An endogenous ligand of cannabinoid receptors; thus, an analog of marijuana that is produced by the brain.
endotherms
Animals (such as birds or mammals) that can regulate their body temperature.
nutrient
Compounds in food that the body requires for proper growth, maintenance, and functioning
osmosis
Diffusion of water through a selectively permeable membrane
lipids
Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.
ketones
Fragments formed by the tissues during incomplete use of fat for energy, and released into the blood.
hypotonic
Having a lower concentration of solute than another solution
diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
osmality
Osmotic concentration of a solution; the number of moles of solute in 1 kg of water times the number of particles into which the solute dissociates
trophic factors
Small proteins in the brain that are necessary for the development, function, and survival of specific groups of neurons.
glycogen
Storage form of glucose
adipose tissue
Tissue that stores fat.
binge eating
a disorder in which a person repeatedly eats too much food at one time
nucleus of the solitary tract
a nucleus of the medulla that receives information from visceral organs and from the gustatory system
PYY3-36
a peptide hormone, secreted by the intestines, that probably acts on hypothalamic appetite control mechanisms to suppress appetite
osmosensory neurons
a specialized neuron that monitors the concentration of the extracellular fluid by measuring the movement of water into and out of the intracellular compartment
glucodetector
a specialized type of liver cell that detects and informs the nervous system about levels of circulating glucose
hypovolemic thirst
a thirst resulting from loss of fluids due to bleeding or sweating (low blood volume)
basal metabolism
amount of energy required to carry out involuntary activities of the body at rest
arcuate nucleus
an arc-shaped hypothalamic nucleus implicated in appetite control
bulimia
an eating disorder characterized by episodes of overeating, usually of high-calorie foods, followed by vomiting, laxative use, fasting, or excessive exercise
anorexia nervosa
an eating disorder in which an irrational fear of weight gain leads people to starve themselves
vasopressin
antidiuretic hormone
hypothalamus plays special role in ____
appetite regulation
appetite controller in ____ in hypothalamus --> responds to ____ (fat levels), ____ --> release ___ which activates ____ to decrease appetite. leptin inhibits ____ --> appetite suppressant. ____ stimulates appetite control + ____ inhibits
arcuate nucleus / leptin / POMC/CART neurons / OCMSTI / MC4R / NPY/AgRP neurons / ghrelin
____ only long-lasting medical intervention in obesite
bariatric surgery
drop in blood volume --> 1. ___ in blood vessels signal the brain 2. ___ reduces urination, 3. kidneys release renin --> ___ reduce blood vessel volume
baroreceptors / vasopressin / angiontensin
baroreceptors
detect changes in blood pressure
motivation
drive state that prompts homeostatic behaviors (e.g. having a drink to intake water)
_____ and _____ regulate body temperature by generating body heat through ____ and capturing heat from external environment
endotherms / ectotherms / metabolism
digestin
enzymatic action that breaks larger organic molecules down into smaller components
obligatory losses
essential fluid losses required to maintain body functioning
hyperphagia
excessive eating
satiety
feeling of fullness
Gluconeogenesis
formation of glucose from noncarbohydrate sources
glycogenesis
formation of glycogen from glucose
brain cells use ____ directly, which is imported with ____, which also stores as ___, ____ converts glycogen back to glucose
glucose / insulin / glycogen / glucagon
nervous system crucial in _____ of temperature, fluid balance, chemical energy, nutrients, and feature ______
homeostasis / negative feedback
orexin
hunger-triggering hormone secreted by hypothalamus
LH
hypothalamic region, lesion --> aphagia
____ from drop in extracellular compartment volume, ___ from increase in osmality
hypovolemic thirst / osmotic thirst
aphagia
inability to eat
Angiotensin II
increases blood pressure by stimulating kidneys to reabsorb more water and by releasing aldosterone
diabetes mellitus
insulin is not secreted adequately or tissues are resistant to its effects
cells function when ____ has correct ratio of salts and ions via ____, ____ is buffer between _____ and outside world
intracellular fluid / osmosis / intracellular compartment
circumventricular organs
lacks a blood-brain barrier; can monitor chemical changes in the blood
anorexigenic neurons
neurons of the hypothalamic appetite system that inhibit feeding behavior
orexigenic neurons
neurons of the hypothalamic appetite system that promote feeding behavior
____ detect extracellular fluid concentration, increase ____ concentration --> water intake
osmosensory neurons / solute
body temperature regulated by ____, ____, and _____
preoptic hypothalamus / brainstem / spinal cord monitor
osmotic pressure
pressure that must be applied to prevent osmotic movement across a selectively permeable membrane
CCK
produced by the small intestine when you eat and tells brain you're full, suppressing appetite
glucose transporters
proteins that assist in the transport of glucose molecules across cell membranes
insulin is crucial for ____
regulation of body metabolism
bariatric surgery
surgical reduction of gastric capacity to treat morbid obesity
extracellular compartment
the fluid space of the body that exists outside the cells
intracellular compartment
the fluid space of the body that is contained within cells
glucose
the form of sugar that circulates in the blood and provides the major source of energy for body tissues. When its level is low, we feel hunger.
thermoregulation
the maintenance of body temperature within a range that enables cells to function efficiently.
hunger
the natural physical drive to eat, prompted by the body's need for food
VMH
the part of the hypothalamus that can cause one to stop eating, lesion --> hyperphagia
set point
the point at which your "weight thermostat" is supposedly set. When your body falls below this weight, increased hunger and a lowered metabolic rate may combine to restore the lost weight
vagus nerve
the tenth cranial nerve that innervates digestive organs, heart and other areas
osmotic thirst
thirst triggered by certain neurons that detect the loss of their own water
hypertonic
when comparing two solutions, the solution with the greater concentration of solutes
isotonic
when the concentration of two solutions is the same
POMC/CART
when these neurons are stimulated they decrease appetite, make POMC & CART
NPY/AgRP
when these neurons are stimulated they increase appetite by making neuropeptide Y and agouti-related peptide