Chapter 9: Internal Regulation Flashcards
______ is the body’s tendency (or attempt) to maintain a specific variable, like temperature, within a fixed range. The median value for the range is known as the ___ ___. The homeostatic process that attempts to reduce discrepancies from the set point is called a ______ _____ (eg ____ when it’s too hot, ____ when it’s too cold).
Homeostasis
set point
negative feedback.
sweating; shivering.
____ is an adaptation where the body will change its set point in anticipation of needs in order to avoid errors (rather than correcting after the fact).
Allostasis
____ ____ is the energy used to maintain a constant body temp at rest, and consumes about ___ of our total energy.
Basal metabolism; 2/3
____ animals (aka ____) maintain their temperature via behavior (move into the sun, the shade, etc.).
Ectothermic; poikilothermic
T or F: unlike ectotherms, humans never use behavior to regulate body temp.
False: find shade, remove layers, layer, build fire, etc.
Ectothermic animals will die in extreme cold due to the formation of ___ ____. One adaptation in some amphibians and reptiles (like Canadian ____ frogs) is the development of ___ in their blood. Other animals will store fluids in the ____ space, they will decrease ____ in the brain, and increase blood ____ in case of any bleeding due to ice crystals.
ice crystals
wood; antifreeze (glycerol)
extracellular, dendrites, clotting
One advantage of being ectothermic is they need far less ____.
fuel
Why is the ideal temp for endotherms 98 - 105?
They gain the advantage of rapid, prolonged muscle activity in cold weather; however, proteins become unstable after 105
Reproductive cells require a ____ environment; this is why males have their _____ outside their core.
cooler; testes
The POA/AH is important for _____ regulation, ___, and ___ behavior.
It receives input from temperature ____ in the skin, in ____, and in the ____ (including the POA/AH itself).
temperature; thirst; sexual.
recepters; organs, brain
The POA/AH receives _____ and ______ from the immune system. This feedback causes the POA/AH to induce _____ responses such as sweating, shivering, heart rate, metabolism, etc. associated with an immune response by sending outputs to other areas, including the ____ nucleus.
prostaglandins and histamines.
autonomic; Raphe nucleus
Fever is directed by the _____. Fevers increase the ____ response and suppress _____ growth. Anything greater than _____ is no bueno, and anything greater than ____ is life-threatening.
hypothalamus.
immune; microbial
103; 105
Water constitutes __% of the human body, and the body strictly adheres to this because all ____ reactions in the body depend on sufficient water.
70; chemical
We regulate water loss by excreting _____ urine during drought and decreasing _____ (when we are at our ___-____ limit). But our most common method is to ____ more than we need.
concentrated; sweating; upper-most.
consume
ADH aka? What does it do? Where is it produced and released? What effect does it have on blood vessels? When are levels increased?
Vasopressin.
It enable the kidneys to reabsorb water from urine.
It’s produced in the hypothalamus, released by the pituitary.
It increases pressure of blood vessels.
Levels increase at night to induce thirst and retain water before sleep.
There are 2 kinds of thirst: ___ thirst and ___ thirst. In ___ thirst, baroreceptors in major blood vessels detect pressure drop from ____ and ____ loss (hemorrhage, diarrhea, intense sweating). In ____ thirst, osmosensory neurons in the brain detect increase of salt in ___ fluid resulting in water being pulled from ____ fluid and ____.
hypovolemic; osmotic.
hypovolemic; fluid and solute.
osmotic; extracellular; intracellular; urine
____ thirst results from neurons losing water.
Osmotic
The ____ and _____ structures of the brain are receptors that detect osmotic pressure and _____ concentration changes within the ____ ventricle.
Additionally, these brain areas receive input from receptors in the ___ ____ - this enables anticipation of osmotic need before dehydration is severe.
SFO (subfornical organ) and OVLT (organum vasculosum laminae terminalis); Na+; 3rd.
digestive tract
The ____ receptor of the third ventricle has one population of neurons that ___ thirst and another that ___ thirst.
Axons combine with input from the ____ receptor (in addition to digestive input) to provide input to the hypothalamus.
However, it’s the ____ _____ area of the hypothalamus that controls drinking.
SFO; increases; decreases.
OVLT.
lateral preoptic area
The supraoptic nucleus and the PVN control the rate of what two hormones produced by the PVN, which are released by what gland?
They control the rate of vasopressin and oxytocin released by the posterior pituitary.
When osmotic thirst is triggered, there are mechanisms in place to monitor swallowing and stomach distention. Why?
These mechanisms help to regulate water intake so that a return to homeostasis can be estimated based on intake - not on the time it takes to alleviate the imbalance (it takes 15 mins for fluid to be absorbed, so the mechanisms “shut off” thirst before osmotic pressure swings in the opposite direction).
Low blood volume and solutes triggers ___ thirst (a preference for ___ water over ____ water). This causes the kidneys to release ____, which causes a release of ______ 1. ____ 1 is converted to ____2 which constricts blood vessels and stimulates cells in the ____ organ to increase drinking.
hypovolemic; (salty; pure)
renin; angiotensin 1.
angiotensin 1; angiotensin 2; SFO (subfornical organ).
Sodium-specific hunger depends on ____ released by the adrenals, specifically _____ which causes the kidneys, salivary and sweat glands to retain salt. ____, together with ____ 2 change the properties of taste receptors on the tongue that cause increased reception to salt.
hormones; aldosterone.
Aldosterone, angiotensin 2.
Typically, small birds eat only what is needed at the moment in order to stay _____ and agile.
In contrast, chickadees in Alaska gain and loose ____% of their total body weight every day - this provides enough energy to maintain _____ metabolism throughout the cold night.
light.
10; basal
Digestion begins in the mouth with the enzyme ____.
amylase
Digestion in the stomach includes the breakdown of some ____, but most nutrition is extracted in the ___ ____. Water absorption and lubrication of undigested material takes place in the ___ ___.
proteins; small intestine.
large intestine
Most mammals lose the intestinal enzyme called ____ during weaning.
lactase
Eating turkey alone causes ____. Eating turkey with carbs reduces competition between _____ (precursor for _____) and phenylalanine. The reduced competition causes an increase in _____ levels, which, in turn, increase ______.
nothing.
tryptophan (melatonin).
tryptophan, melatonin.
T or F: The act of chewing (as in chewing gum) provides feelings of satiety.
False: it provides “some” satiety, but not enough to stop hunger.
The main signal to stop eating is ____ of the ____ and _____. The main nerves that transmit these signals are the ___ nerve (cranial nerve __) and ____ nerves.
A secondary signal to stop eating lies in ____ receptors within the ____. These receptors transmit data regarding the ____ of nutrition being consumed.
distention of the stomach and duodenum.
vagus (X) and splanchnic
tastes; duodenum.
Type.
Distention of the duodenum releases ___ which limits meal size in 2 ways:
- It constricts the ____ muscle between the ____ and ____; this causes the ___ to fill more quickly.
- It stimulates the ___ nerve which sends signals to the ____ to release more ____ and trigger decreased feeding.
CCK
sphincter; stomach; duodenum; stomach
vagus; hypothalamus; CCK
