Task 7 Flashcards
Homeostasis
Alterations to it cause what?
Active proccesss of maintaining a psychological parameter relatively constant.
Causes motivation
Obligatory losses
require us to gain and conserve heat, water, and food constantly because we involntarily loose energy, water , or temperature as a consequence of life processes.
Ingestive behavior
Eating or drinking
System variable
A variable that is controlled by a regulatory mechanism, for exapmle temperature in a heating syste.m
set point
The optimal value of the system variable in a regulatory mechanism.
Detector
In a regulatory proccess, the mechanism that is capable of changing the value of the syste variable.
Correctional mechanism
In a regulatory proccess, the mechanism that is capable of changing the value of the system variable.
Negative feedback
A proccess whereby the effect produced by an action servers to diminish or terminate that action; a characteristis of regulatory systems
Satiety mechanims
A brain mechanism that causes cessation of hunger or thirst, produced by an adequate and available supplies of nutrients or water.
intracellular compartment
Fluid that exists within the cells
EXtracellular compartment
Fluid that exists outside the cells, acts as a buffer and as an indicator of condiitions in the intracellular compartment( it constantly controls if we need water).
Interstitial fluid
Fluid between the cells
Blood plasma
the protein rich fluid that carries red and white blood cells
Aquaporins
Channels in the cell membranes tht are specialized for conducting water molecules into or out of the cell ( a single channel can conduct over 3 billion molecules of water per second).
Intravascular fluid
The fluid found within the blood vessels.
Hypovolemia
Reduction in the volume of the intravascular fluid.
What are the two forces that describe the movement so fwater
Diffusion and Osmosis
Diffusion
Molecules of a substance(like salt) dissolve in a quantity of another substance(water) will passively sprezad through the substance(water) because of he random movement sof the molecules until they are more or less uniformly distributed throughout the glass.
Osmosis
Movement of water molecules that occurs when a semimpermeable membrane separates solutions containing differenct concentrations of solute, and the solute ccannot spread itself evenly across both sides (like membrane blocks the passage of salt)
Osmotic pressure
Physical force that pushes or pulls water across the membrane
Osmolality
Number of solute particles per unit volume of solvent
Osmotic thirst
High extracellular concentration of solute like sal t, trigered by increased saltiness of the extracellular fluid
osmosensory neurons
specialized neuron that measures the movemen tof water into nd out of the cells because theya re stretchy( they easily shrink and stretch). Theyre found in several regions of the hypothalamus, including the preoptic are, anterior hypothalamus, the supraoptic nucleus, and the organum vasculosum of the lamina terminalis.
Osmoreceptor
A neuron that detects changes in the solute concentration of the interstitial fluid that surrounds it
Median preoptic nucleus
A small nucleus situated around the decussation of the anterior commissure; plays a role in thirst stimulated by angiotensin.
Hypovolemic(volumetric) thirst
Low extracellular volume due to the loss of body fluids (loss of water volume). Thirst produced by hypovolemia. Caused by blood loss, vomit and diarrhoea.
HYpovolemia
Low volume,of the extracellular fluid because normal everyday losses cause moderate decreases in the extracellular fluid.
Low fluid volume equals whta?
No working blood vessels( they cant strethch and theyre not full as usual).
Baroreceptor
Pressure receptor in the heart or a major artery that detects a fall in blood pressure.
Atrial natriuretic peptide
A hormone, secreted by the heart tha normally reduces blood pressure, inhibits drinking -, and promotes the excretion of water and salt at the kidneys.
aldosterone
an adrenal steroid that promotes conservation of sodium by the kidneys
vasopressin (or antidiuretic hormone ADH)
a peptide hormone from the posterior pituitary gland that promotes the reduction of water flow to the bladder(before the urethra)
angiotensin II ( keep reading in ipad)
substance that may play a role in the control of thirst, controls blood vessels and increases blood pressure. It also triggers the release of two different hormones that affect fluid balance:
Aldosterone
Vasopresin
Nutrient
A chemical that is needed from growth, maintenance, and repair of the body but is not used as a source of energy
Digestion
The proccess of breaking down the ingested food
trophic factors
A substance that promotes cell growth and survival
What is glucose
A sugar molecule used by the body and brain for energy
Glycogen
A complex carbohydrate derived from glucose
Glycigenesis
The physiological proccess by which glycogen is produced
Glycogenlysis
the cnversion of glycogen back into glucoses triggered when blood concentrationns of glucose drop too low.
Glucose transporter
A molecule that conducts glucose molecules through the external membrane of a cell for use inside
Gluco privation
A dramatic fall in the level of glucos available to cells; can be caused by a fal in the blood level of glucose or by drugs that inhibit glucose metabolism.
Insulin
lower blood glucose, it is a hormone, released by beta cell sin th eislets of langerhans(pancreas)
Mechanisms i th ebody that after injecting insulin release insulin
Cephalic phase(fasting phase) Digestive phase(fasting phase) Absortive phase
Cephalic phase
or fasting phase…
sensory stimuli from food
DIgestive phase
food entering th estomach and intrstines causes them to release gut hormones, some which stimulate the pancreas to release insulin
Absorptive phase
Gludetectors detect the glucose entering the bloodstream and signal the pancreas to release insulin.
GLUCODETECTOR
A cell tha detects and informs the nervous system about the levels of circulating glucose
How do glucodetectors travel through the liver?
Vagus nerve
Nucleus of the solitary tract
Vagus nerve
Cranial nerve X, which regulates the viscera(organs) and transmits signals from the viscera to the brain.
Nucleus of the solitary tarct (NST)
A brainstem nucleus that receives visceral and taste information via several cranial nerves.
