A & P - College Network - Chapter 3 Maintenance Of The Internal Environment

Front 1

Active Transport

Back 1

Involves the expenditure of extra energy from the cell's own energy reserves and can result in net movement of solute against a concentration gradient.

Front 2

Adenosine Triphosphate

Back 2

In primary active transport, the carrier derives its energy from APT.

Front 3

Antiport

Back 3

One solute may be exchanged for another in a process of exchange.

Front 4

ATPase

Back 4

A large family of enzymes.

Front 5

Blood Plasma

Back 5

The fluid component of blood.

Front 6

Carriers

Back 6

Proteins that actually bind individual solute molecules on one side of the membrane and release the solute on the opposite side of membrane.

Front 7

Channels

Back 7

Barrel-shaped pores that enclose a small water-filled passage through which solutes diffuse as if in a free solution.

Front 8

Cotransport

Back 8

Multiple solutes of different types may need to bind to the carrier before all are translocated.

Front 9

Diffusion

Back 9

The movement of a substance due to random movement of its individual particles.

Front 10

Diffusion Coefficient

Back 10

A factor that determines the rate of net movement of a substance by diffusion, it is a property that depends on the particle size of the substance and the nature of the medium in which diffusing occurs.

Front 11

Diffusion Potential

Back 11

The charge separation generated by this process can be measured as an electrical voltage between the two chambers.

Front 12

Distance

Back 12

A key factor that determine the rate of net movement of a substance by diffusion. Greater distances reduce the rate of net movement.

Front 13

Effectors

Back 13

Changes the regulated variable in the direction of the setpoint.

Front 14

Endocytosis

Back 14

A process of cellular uptake in which a small region of the plasma membrane is first indented to form a pocket and then is pinched off to form an endocytotic vesicle.

Front 15

Endocystotic Vesicle

Back 15

A packet of plasma membrane containing anything that was within the pocket when it formed.

Front 16

Enyzmes

Back 16

Any of a very large class of complex proteinaceous substances (as amylases or pepsin) that are produced by living cells, that are essential to life by acting like catalysts in promoting at the cell temperature usually reversible reactions.

Front 17

Equilibrium Potential

Back 17

The magnitude of the equilibrium potential (E) is directly related to the magnitude of the concentration gradient, since one must balance the other.

Front 18

Exchange

Back 18

A process in which one solute may be exchanged for another (antiport).

Front 19

Exocytosis

Back 19

A process in which intracellular vesicles fuse with the plasma membrane and release their contents to the exterior.

Front 20

Exothermic

Back 20

Heat-releasing.

Front 21

Extracellular Compartment

Back 21

All the solution outside cells.

Front 22

Extracellular fluid

Back 22

All the fluid outside the cells, which has two main components: the interstitial fluid and blood plasma.

Front 23

Hypertonic

Back 23

A solution that contains a higher impermeant solute concentration and causes cells to shrink.

Front 24

Hypertonic Challenge

Back 24

A homeostatic challenge that adds additional impermeant solute to the ECF without changing the total water content of the body will drive movement of water from the intracellular compartment to the extracellular compartment until the osmotic concentrations of both compartments are again equal, but higher than normal.

Front 25

Hypotonic

Back 25

A solution that contains a lower concentration of impermeant solute than normal cytoplasm (and therefore a higher osmotic strenght) and causes cells placed in it to swell.

Front 26

Hypotonic Challenge

Back 26

A homeostatic challenge that decreases total extracellular solute will result in osmotic flow of water into the cells until the osmotic concentration of the two compartments becomes equal, but lower than normal.

Front 27

Interstitial Fluid

Back 27

Fluid that immediately surrounds cells in tissue.

Front 28

Intracellular Compartment

Back 28

A compartment, which is surrounded by a water-permeable barrier, that holds all of the cytoplasm of a cell.

Front 29

Ions

Back 29

Atoms or molecules that have an electrical charge.

Front 30

Isotonic

Back 30

Solutions throughout most organs and tissues in which the osmotic concentration of the cytoplasm is approx. 300 mOsmoles/liter.

Front 31

Law of Electroneutrality

Back 31

Ions never stay more than a short distance away from a corresponding counterion.

Front 32

Ligand-Gated Channels

Back 32

Many channels are opened or closed (gated) by external influences. Ligand-gated channels respond to the binding of messenger substances from inside or outside the cell.

Front 33

Muscle Tone

Back 33

A constant low level of tension in all muscles.

Front 34

Na+/K+ ATPase

Back 34

Found in virtually all cells, the Na+/K+ pump.

Front 35

Na+/K+ Pump

Back 35

In each of its cycles, the Na+/K+ pump splits 1 ATP and mediates the ejection of 3 Na+ from the cell in exchange for 2 K+ moved from outside to in. Since cytoplasm contains a higher concentration of K+ than extracellular fluid, the situation is the reverse for Na+. Both Na+ and K+ are moved against their concentration gradients by the pump.

Front 36

Na+ -glucose

Back 36

Uses the downhill gradient Na+ into the cells, which is generated by the Na+/K+ pump, to drive glucose into the cell against its concentration gradient.

Front 37

Negative Feedback

Back 37

Designed to minimize deviations from a setpoint value of some variable feature of the environment, such as temperature. It works by having sensors that can measure the regulated variable, controllers that can compare the measured value with the setpoint, and by activating effectors that can move the variable in the direction of its setpoint.

Front 38

Nernst Equation

Back 38

The mathematical relationship between the two forms of energy - electrical and chemical - is described by the Nernst equation: Ek+ = RT/zF 1n ([K+])left/[K+]right).

Front 39

Osmometer

Back 39

A device in which two rigid compartments are separated by a barrier that is permeable to water but not to solute. One compartment contains pure water, the other contains solution of unk concentration.

Front 40

Osmosis

Back 40

Diffusive movement of water down a water concentration gradient.

Front 41

Osmotic Pressure

Back 41

An equilibrium pressure directly related to the concentration of solute particles.

Front 42

Passive Transport

Back 42

Net movement of substances by diffusion; does not require the input of extra energy from cellular metabolism.

Front 43

Permeant Substances

Back 43

Very small molecules (like water) or substances that can dissolve in lipids.

Front 44

Phagocytosis

Back 44

A process in which cells of the immune system can engulf whole bacteria or particles of foreign material.

Front 45

Pinocytosis

Back 45

The uptake of extracellular fluid with water and solutes.

Front 46

Primary Active Transport

Back 46

The carrier derives its energy from adenosine triphosphate (ATP).

Front 47

Pyrogens

Back 47

Fever Inducers.

Front 48

Receptor-Mediated Endocytosis

Back 48

The movement to the cellular interior certain membrane proteins, together with specific extracellular substances that have become bound to the receptors. It is important method of regulating the number of receptor proteins in the plasma membrane.

Front 49

Receptors

Back 49

Membrane proteins in the cellular interior.

Front 50

Resting Potential

Back 50

A difference in electrical charge between the cytoplasmic and extracellular sides of the plasma membrane.

Front 51

Secondary Active Transport

Back 51

Processes not driven by ATP but by a transmembrane gradient of some other solute.

Front 52

Sensors

Back 52

In negative feedback, sensors measure the state of the regulated variable and pass this information to a controller that compares it with predetermined setpoint.

Front 53

Setpoint

Back 53

A set value of some variable feature of the environment, such as temperature.

Front 54

Symport

Back 54

Multiple solutes of different types may need to bind to the carrier before all are translocated.

Front 55

Synaptic Transmission

Back 55

Chemical signals between neurons and neurons or betwen neurons and muscle cells.

Front 56

Thermogenesis

Back 56

Means of increasing heat production within the body.

Front 57

Transport ATPase

Back 57

Carrier proteins, of which most common form is the Na+/K+ pump, found in virtually all cells.

Front 58

Transport Proteins

Back 58

Proteins that span the cell membrane, providing alternative routes through the membrane. There are two types of transport proteins: channels and carriers.

Front 59

Voltage-Gated Channels

Back 59

Many channels are opened or closed (gated) by external influences. Voltage-gated channels respond to changes in membrane potential.