Human Physiology Test Two

Front 1

What is diffusion?

Back 1

The passive movement of molecules from one location to another as a result of their own thermal motion.

Front 2

What is osmosis?

Back 2

The passive movement of water across a membrane down its concentration gradient

Front 3

What is osmotic pressure?

Back 3

An indirect measure of a solute's concentration, expressed in ordinary units of pressure.

Front 4

What is osmolarity?

Back 4

The total concentration of solute particles in a solution

Front 5

What is a hypertonic solution?

Back 5

A solution that draws water out of a cell causing the cell to shrink.

Front 6

What is a hypotonic solution?

Back 6

A solution that causes water to enter a cell causing the cell to swell.

Front 7

What is an isotonic solution?

Back 7

A solution that will not alter cell volume.

Front 8

What is exocytosis?

Back 8

The transport of material out of a cell via vesicles that fuse with the plasma membrane; involved in the cellular secretion of hydrophillic molecules.

Front 9

What is phagocytosis?

Back 9

The process by which a cell engulfs microorganismas, abnormal cells, and foreign particles present in blood and tissues.

Front 10

What is endocytosis?

Back 10

The uptake of material into a cell via vesicles that pinch off from the plasma membrane; enables macromolecules and larger particles to enter cells.

Front 11

What are lysosomes?

Back 11

Small spherical membrane-bounded organelles containing numerous degradative enzymes; involved in the breakdown of unneeded intracellular material or foreign matter that has been taken into the cell.

Front 12

What is the Golgi apparatus?

Back 12

An organelle consisting of membrane-bound flattened sacs called cisternae that process molecules synthesized in the endoplasmic reticulum and prepares them for transport.

Front 13

What is another name for facilitated diffusion and what is it?

Back 13

Receptor Mediated Diffusion - the passive movement of molecules across a membrane by way of a transport protein.

Front 14

What is the osmolarity of a solution?

Back 14

The total concentration of solute particles in a solution. predicts strength or ability of osmotic pressure.

Front 15

What is the membrane potential?

Back 15

A difference in electrical potential or voltage that appears across the membranes of most cells.

Front 16

What is active transport?

Back 16

Any method of protein-mediated transport of molecules across a membrane that requires the use of energy.

Front 17

What are "pumps"?

Back 17

Proteins that actively transport molecules across a membane.

Front 18

What is an electrochemical gradient?

Back 18

The sum of the electrical and chemical gradients acting on an ion or charged molecule.

Front 19

What is a "sodium-potassium pump"?

Back 19

A protein that utilizes ATP to actively transport sodium ions out of the cell and potassium ions into the cell against their electrochemical gradients.

Front 20

What is the resting membrane potential?

Back 20

The voltage that exists across a cell membrane when the cell is not transmitting electrical signals; polarity is such that the inside of the cell is negative with respect to the outside.

Front 21

What is the cell's ability to maintain the Resting Membrane Potential dependent on?

Back 21

How fast the pumps are running and the number of pumps

Front 22

What is the action potential?

Back 22

Large changes in the membrane potential of exciable cells in which the inside of the cell becomes positive relative to the outside; function in transmitting information over long distances in axons. A momentary reversal of charge. Serves as an electrical signal to cell.

Front 23

What is depolarization?

Back 23

Any change in membrane potential in which the inside of the cell becomes more positive (less negative) than it is at rest.

Front 24

What is the threshold?

Back 24

In an excitable cell, the critical value of the membrane potential to which the cell must be depolarized in order to trigger an action potential.

Front 25

What is repolarization?

Back 25

The return of the membrane potential of a cell to the resting potential following a depolarization.

Front 26

What is hyperpolarization?

Back 26

Any change in membrane potential in which the inside of the cell becomes more negative than it is at rest.

Front 27

What is an axon?

Back 27

A branch that extends from the cell body of a neuron and sends information to other neurons or effector cells via action potentials and release of neurotransmitter.

Front 28

What is the axon terminal?

Back 28

The end of the axon that forms a synapse with another neuron or an effector cell.

Front 29

What is the axon hillock?

Back 29

The site where the axon originates from the cell body of a neuron and the point of initiation of action potentials; trigger zone

Front 30

What is a dendrite?

Back 30

Banches that extend from the cell body of a neuron and receive information from other neurons.

Front 31

What is subthreshold?

Back 31

In nervous system, a stimulus too weak to generate an action potential.

Front 32

What is an activation gate?

Back 32

One of two gate that regulate the opening and closing of voltage-gated sodium channels, represents the portion that opens with depolarization.

Front 33

What is the refractory period?

Back 33

The period of reduced membrane excitability; during and immediately after an action potential when the membrane is less excitable than it is at rest.

Front 34

What is an inactivation gate?

Back 34

One of two types of gates in voltage-gated sodium channels; close slowly in response to depolarization.