Chapter 9 Flashcards
the physiological state of the body in which internal physical and chemical conditions are kept within a range that is suitable for life processes
homeostasis
the extracellular fluid, which consists of the fluid that surrounds the cells and tissues in the body and the plasma portion of the blood
internal environment
the fluid that surrounds the body cells
interstitial fluid
a system that monitors internal and external conditions and changes bodily functions to maintain homeostasis
homeostatic mechanism
the response of a system that acts to maintain equilibrium by compensating for any changes made to the system
negative feedback
the element of a feedback system that detects changes in the environment
sensor
the optimal value for a given variable of a system
set point
the element (or elements) of a feedback system that acts to return the system to its optimal state
effector
the element of a feedback system that compares existing conditions with ideal conditions
integrator
the response of a system that acts to increase the effect of any changes made to the system
positive feedback
the regulation of internal temperature by negative feedback mechanisms
thermoregulation
an animal that maintains a stable body temperature regardless of the temperature of the external environment
homeotherm
an animal whose body temperature varies with, and often matches, the temperature of the external environment
poikilotherm
an animal that maintains its body temperature by internal mechanisms
endotherm
an animal that maintains its body temperature by absorbing thermal energy from the environment
ectotherm
the process by which an animal gradually adjusts to temperature changes in its environment
thermal acclimatization
a short-term state of reduced metabolic rate and body temperature that reduces the demand for energy during the night or day
torpor
a state of greatly reduced metabolic rate and activity that enables an animal to survive the winter by reducing the demand for energy when food is unavailable
hibernation
a state of torpor that enables an animal to survive the summer by reducing the demand for energy
estivation
the pressure that results from a difference in solute concentration between the two sides of a selectively permeable membrane
osmotic pressure
the property of the solution on one side of a selectively permeable membrane that has the lower concentration of water
hyperosmotic
the property of the solution on one side of a selectively permeable membrane that has the higher concentration of water
hyposmotic
the property of two solutions that have equal water concentrations
isoosmotic
the process of actively regulating the osmotic pressure of bodily fluids and cells
osmoregulation
a structure in a single-celled organism that maintains osmotic equilibrium by pumping excess fluid out of the cell
contractile vacuole
an excretory organ in some invertebrates that is used to reabsorb and eliminate wastes
metanephridium
the main organ of excretion in insects, which is used to carry wastes to the intestines
Malpighian tubule
the tiny functional unit of the kidney that filters wastes from the blood
nephron
a small folded structure in the human kidney that encircles the glomerulus
Bowman’s capsule
a network of capillaries within the Bowman’s capsule that performs the first step in the filtration of blood
glomerulus
a vessel that supplies blood to the nephrons in the human kidney
afferent arteriole
a vessel that carries away filtered blood from the nephrons in the human kidney
efferent arteriole
a net of capillaries in the nephrons that reabsorb essential ions and minerals from filtered blood
peritubular capillaries
the duct portion of a nephron that connects the Bowman’s capsule to the loop of Henle
proximal convoluted tubule
the U-shaped part of the duct that connects the proximal convoluted tubule to the distal convoluted tubule
loop of Henle
the duct portion of a nephron that connects the loop of Henle to the ducts that lead to the renal pelvis
distal convoluted tubule
the process in which blood and fluid pass through a selectively permeable membrane
filtration
the transfer of water, ions, and nutrients back to the interstitial fluid via passive and active transport
reabsorption
a membrane protein that passively transports water molecules
aquaporin
the removal of waste materials from the blood and intercellular fluid
secretion
