a characteristic of a plasma membrane where it will allow some substances into the cell but not other substances
2. diffusion, osmosis, transport proteins, and active transport

main building block of a membrane

fluid: the membrane is more fluid than solid because the proteins and phospholipids move laterally
Mosaic: because it is composed of manny different macromolecules
Model:

1. molecules that are hydrophobic (non-polar)

Some small/ non-polar molecules
1. O2 and CO2

large molecules

hydrophilic (polar)
1. Na+ and Cl-

the spontaneous movement of a substance from the regions of higher concentration to regions of lower concentration without the need of energy

1. high concentration of Na+, Ca2+ & Cl-
2. high concentration of K+

a difference in amount of stuff in two different areas

the direction and rate of diffusion

1. chemical concentration gradient
2. electrical concentration gradient

1. the concentration of a substance
2. the charge of the substance compared to the charge in the cell

describes both the effects of the electrical concentration gradient and the chemical concentration gradient

...

majority of ions come into the cell from outside of the cell

A. faster
B. more

specific for certain things

equilibrium state

1. a level of attractive force
2. a level of repelling force

A. look at the charge inside the cell
B. look at how much of that substance is inside the cell
C. which direction will it move
D look at the charge of the ion
E. look at how much of that substance is outside of the cell

the balance between both the gradients

1. types of leaky channes
2. types of transporters
3. number of channels/ transporters

1. leaky channels: always open
2. gated channes: could be open or closed

1. chemical- gated: opened by chemicals
2. voltage-gated: opened by electrical charge
3. mechanical
4. thermal-gated: opened by temp.

A. Specific non-lipid-soluble molecules or ions
B. non-lipid-soluble molecules
C. lipid-soluble molecules
D. membrane channel
E. concentration gradient

1. energy
2. facilitated diffusion
3. GLU transporter (Glucose)

the protein changes shape

ATP (energy)
- active transport

1. sodium potassium pump

1. no
2. those that do directly use energy
3. secondary active transport (fake)
4. to help glucose move up its concentration gradient

...

diffusion of water across a selectively permeable membrane

1. high concentrations of solute (low water)
2. low concentrations of solute (high water)
3. equal concentration of solute on each side

the ejection of cytoplasmic materials by the fusion of a membranous vesicle with the plasma membrane

the movement of extracellular material into the cytoplasm via the formation of a membranous vesicle at the cell surface.

A. dendrites B. nissle bodies C. axon hillock
D. axolemma E. axon F. synaptic terminals
G. nucleus H. nucleolus

a membrane potential

the difference in the electrical charge between the inner membrane and the outer membrane

1. changeable membrane potential (neurons and muscle cells)
2. cannot change membrane potential (all other cells)

ions, amino acids, and proteins

differences in charge across a membrane. (different concentrations of + and - charges

concentrations of K+, Na+, Cl- and others

1. inside the cell
2. outside the cell

A. both chemical and electrical gradient influence
B. now just chemical
C. now diffusion is slowed down b/c electrical gradient is getting more and more +

D. now Na+ is stopped diffusing b/c such a high gradient. (no net diffusion = electrochemical equilibrium) => ENa+ = +60mV
E. It is so positive it is now pushing Na+ out of the cell

1. +60 mV
2. -90 mV

1. no more net diffusion => Ek+ = -90mV

where a neuron talks to another cell

the soma
the synaptic terminals

movement to and from a neurons cell body

1. movement towards synaptic terminal
2. movement towards soma of neuron

1. A. slow stream
B. 1-3mm per day
2. C fast stream
D. 5-10mm per hr

1. the movement of stuff (NTs)
2. action potentials

motor protein

by increasing the permeability of the membrane to allow ions to move across

1. you generate a current
2. that changes the membrane potential
3. creation of a graded potential
4. move to regions of lower concentrations

a temporary slight change in the memb. potential
a. bigger change
b. smaller change

how neurons send the message along the axon to communicate to the next neuron

excitable cells
- muscle membranes and neuron membranes

- a brief "transient" change in the membrane potential in response to a stimulus

causes a change in the permeability of the membrane

threshold

to cause enough of an increase in the permability of the cell membrane to significantly change the RMP of that fart of the membrane to initiate action potentials

changes in ion flow

1. absolute refractory periods
2. relative refraxtory

1. not able to start AP
2. can start an AP if big enough

A. absolute refractory
B. end of relative refractory
C. resting membrane potential

A. may be able to send AP if enough stimulus
B. can't send an AP

1. influence the membrane potential at the initial segment
2. influence the release of neurotransmitters
3. influence the duration of the NTs at the synapse

a. inhibit or excite
b. temporal and spatial

we excited the postsynaptic memb. so that it didn't exactly reach threshold (-55mV) but it did have a little more + charge (could be -69, -60, etc)

- either introduce a - charge or a + charge ion
- GABA could land on a Cl gated channel which lets in Cl-
-Cl- could attract + charged ions making initial segment more negative

rapidly repeated stimulation from one synaptic knob

2 or more synaptic knobs simultaneously stimulating

facilitate or inhibit

serotonin influencing Ca2+ channels make it so that they are open, so more exocytosis, so more NT release

GABA influences Vg Ca2+ channels making it so that Ca2+ cant get in, so no exocytosis, so not much NT release

1. only on somas and dendrites
2. only on synaptic terminals

1. degredation of NTs
2. Reuptake

enzynmes break down the NTs

NTs are taken back up into the presynaptic neuron

1. enzyme activity
2. preventing reuptake

1. MAOs
2. MAOIs = monoamine oxidase inhibitors

1. breaks down NTs
2. stops the break down of NTs

1. medications that are general (TCA=tricyclics)
2. medications that are specific (SSRIs = serotonin selective reuptake inhibitors)

1. affects 3-4 NTs
2. only affects serotonin so that serotonin can stay in the cleft longer

a signal

1. changes in membrane potential that gets weaker as it travels away from the source
a. short
b. slowly
c. in dendrites and somas

2. keep their same strength no matter how far they travel
a. great
b. very fast
c. axon hillocks to axon terminals

based on diameter or velocity
1. type A fibers
2. type B fibers
3. Type C fibers

1. largest
2. very fast - 268mph
3. myleinated
4. sensory input- reflexes

1. smaller diameter
2. 40 moh
3. myelinated

1. smallest in diameter
2. very low 2 mph
3. unmyelinated
4. pain signals

1. cholinergic fibers
2. adrenergic fibers

1. fibers that release acetylcholine
2. fibers that release norepinephrine or epinephrine

1. cholinergic receptors for Ach
2. adrenergic receptors for norepinephrine

1. nicotinic receptors
2. muscarinic receptors

1. many different types
2. skeletal muscle tissue

a. 5 different types
b. cardiac tissue

a. alpha
b. beta

both Ach and norepinephrine

only Ach

up to 50,000