Human Physiology Exam #2

Front 1

Generally thee Plasma membrane is not permeable to?

Back 1

Proteins, nucleic acids, or other Large molecules ( it is permeable to ions, nutrients, and wastes)

Front 2

Simple Diffusion

Back 2

no membrane protein involved- movement of molecules through bilayer from high concentration to low concentration

Front 3

Facilitated Diffusion

Back 3

involves integral membrane proteins, including channels and carriers. causes some sort of conformational change to allow something through the bilayer

Front 4

Active Transport

Back 4

Requires integral membrane proteins (carriers and pumps) Moving molecules across the membrane but against the gradient. REQUIRES THE INPUT OF ENERGY!!

Front 5

Osmosis

Back 5

Simple diffusion of water

Front 6

Diffusion through Phospholipid bilayer

Back 6

-pure phospholipid bilayers are selectively permeable
-small or nonpolar molecules move across phospholipid bilayers quickly
-charged or larger polar molecules cross slowly, if at all

Front 7

What and Why Diffusion?

Back 7

If a membrane is permeable to solute, net diffusion occurs sown a concentration gradient. If molecule is charged electrochemical gradient.

Front 8

What and Why Osmosis?

Back 8

If a molecule is impermeable to the membrane then osmosis causes water to move toward the area of higher solute. (remember water will move to make sure that the amount of solute per volume is equal)

Front 9

Channel Protein

Back 9

Channels facilitate diffusion (still moves things from high to low concentration). Always Passive. Most are gated (can be opened or closed in response to some signal)

Front 10

Carrier Protein

Back 10

Carriers bind to molecules that are being transported. Causes a conformational change to transport to inside of cell. Still Passive!

Front 11

Primary Active Transport

Back 11

the sodium-potassium pump (Na/K)- this pump uses energy from ATP to pump ions against their electrochemical gradient. directly uses energy to transport molecules across a membrane

Front 12

Secondary Active Transport

Back 12

In contrast to primary active transport, there is no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of the cell is used.

Front 13

Antiport

Back 13

two ions or other solutes are pumped in opposite directions across a membrane.One of these species is allowed to flow from high to low concentration which yields the entropic energy to drive the transport of the other solute from a low concentration region to a high one.

Front 14

Symport

Back 14

Symport uses the downhill movement of one solute species from high to low concentration to move another molecule uphill from low concentration to high concentration (against its electrochemical gradient). The two species move in the same direction across the membrane.

Front 15

The two subdivisons of the Nervous system

Back 15

Central Nervous System and Peripheral Nervous System

Front 16

Central Nervous System (Structures)

Back 16

Brain and Spinal Cord

Front 17

Peripheral Nervous System( Structures)

Back 17

Everything else besides the Brain and spinal cord including cranial and spinal nerves

Front 18

The Nervous system consists of 2 kinds of cells

Back 18

Neurons and Glial cells

Front 19

Neurons gather,process and transmit information by:

Back 19

responding to stimuli, producing and carrying electrochemical impulses and releaseing chemical messages

Front 20

Neuron Structure

Back 20

Cell Body- contains nucleus
Dendrites- recieve information from other cells
Axon- conduct impulses away from cell body

Front 21

Sensory/ Afferent neurons

Back 21

-neurons conduct implulses INTO CNS

Front 22

Motor/ Efferent-

Back 22

neurons carry impulses OUT OF CNS

Front 23

Interneuron

Back 23

integrate nervous system activity . located entirely inside CNS

Front 24

Neuron Classifications(Functional)

Back 24

Front 25

Neuron Classifications (Structural)

Back 25

Front 26

Pseudounipolar Neurons (Structure)

Back 26

the cell body sits along side of single process
many sensory neurons have this structure

Front 27

Bipolar Neurons (Structure)

Back 27

the dendrite and axon arise from opposite ends of cell body
found in retinal neurons

Front 28

Multipolar Neurons (Structure)

Back 28

have many dendrites and one axon
motor neurons and many other types are multipolar

Front 29

Glial Cells in CNS

Back 29

Oligodendrocytes, Microglia, Astrocytes, Ependymal

Front 30

Glial Cells In PNS

Back 30

Schwann Cells and Satellite Cells

Front 31

Schwann Cells

Back 31

Myelinate PNS axons

Front 32

Oligodendrocyte

Back 32

Myelinates several CNS axons

Front 33

Ependymal Cells

Back 33

Neural Stem Cells

Front 34

Myelination

Back 34

this process electronically insulates the axon. Myelination enables nerve cells to transmit information faster and allows for more complex brain processes.

Front 35

Resting Membrane Potential

Back 35

unequal distribution of ions across the PM. Internal area has negative charge relative to external. Th Na/K pump causing electrochemical gradient, very limited permeability of Na(sodium), Relatively high permeability of K(potassium). -70mV is typical

Front 36

Astrocytes

Back 36

most common glial cell in CNS. Involved in:
buffering potassium levels, recycling neurotransmitters, regulating adult neurogenesis, releasing transmitters that regulate neuronal activity.

Front 37

Action Potential

Back 37

an action potential is a wave of membrane potential change that sweeps along the axon from cell body to synapse
this wave is formed by rapid depolarization of the membrane by Na+ influx, followed by rapid repolarization by K+ efflux

Front 38

Depolarization

Back 38

Occurs when the membrane potential becomes LESS
negative than resting potential

Front 39

Hyperpolarization

Back 39

Occurs when the membrane potential becomes MORE
negative than resting potential

Front 40

Action Potential (Mechanisms)

Back 40

-depolarization and repolarization both occur via diffusion of ions down their electrochemical gradients
-the action potential itself does not require active transport
-the Na+/K+ pump maintains the ion gradients by using energy from ATP hydrolysis to pump out Na+ and pump in K+

Front 41

Action Potentials Are All-or-None

Back 41

when the membrane potential reaches threshold, an AP is irreversibly fired the amplitude of the action potential is a property of the membrane and its embedded voltage-gated channels; the intensity of the stimulus is irrelevant as long as it is sufficient to cause the membrane to reach threshold

Front 42

Refractory period

Back 42

the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following an excitation

Front 43

Absolute refractory period

Back 43

interval during which a second action potential absolutely cannot be initiated, no matter how large a stimulus is applied. Na+ channels are inactivated

Front 44

Relative refractory period

Back 44

interval immediately following during which initiation of a second action potential is inhibited but not impossible. another action potential is more difficult to initiate because voltage-gated K+ channels are still open

Front 45

Action Potential Speed

Back 45

action potential travels faster along an axon with a greater diameter and myelinated

Front 46

Synapse

Back 46

is a functional connection between a neuron(presynaptic) and another cell (postsynaptic)
Chemical (Large majority) and Electrical (rare among neurons)

Front 47

Chemical synapses

Back 47

-the two cells are separated by a small space called the synaptic cleft. neurotransmitters are stored in synaptic vesicles in the axon terminus of the presynaptic neuron.
-when an action potential reaches the axon terminus, the vesicles fuse with the presynaptic membrane neurotransmitters are released by exocytosis
-amount of neurotransmitter released depends on the frequency of action potentials

Front 48

postsynaptic potentials

Back 48

graded potentials – they are not all-or-none, they vary in intensity, they decease with time and with distance along the cell body and dendrites