neurophysiology

Question 1

how do you call the canyon and mountain like structures of the brain ?

Answer 1

gyri
sulci

Question 2

what is grey and what is white matter in the brain ?

Answer 2

Grey matter –unmyelinated nerve cells bodies (cerebral cortex)
White matter –myelinated axons

Question 3

what kind of desease is schizophrenia and what about altzheimers and parkinsons ?

Answer 3

neurodevelopmental( schizo)

neurodegenerative( altz, parkinsons)

Question 4

The anatomy of the CNS – key concepts? Cerebral cortex

Answer 4

Lobes= Frontal , Pariental, occipital,temporal

also brodmann’s areas are more specific= 1,2,3,4,5,…

Question 5

The anatomy of the CNS – key concepts?
Subcortical nuclei

Answer 5

Telengephalon
*Basal ganglia
*Amygdala

Diencephalon

*Hippocampus
*Thalamus
*Hypothalamus
*Pituitary
*Pineal gland

Question 6

how does The cerebral cortex work as a center for integrating sensory
information and a decision-making region

Answer 6

1.Primary sensory area
2.Corresponding association area
(integration)
3.Perception

Question 7

Motor cortex

Answer 7

Primary motor cortex
Motor association cortex (premotor cortex)

Question 8

The lateralization principle is real?

Answer 8

yes but it is just that some roles are more pronounced in some areas of the brain in relation to others.

Question 9

where is th Processing of spoken and visual language done in the brain ?

Answer 9

wernike’s and broca’s areas

W- you speak but it doesn’t make sense because you dont understand

B- Telegram speaking,Aphasia but you understand

Question 10

Example of emotions in the brain

Answer 10

Fear of a lion –sensory input – thalamus processing it – cortex higher lvl of processing info ( event registered now) ( compare the real lion to the lion in the textbook) – Lympic system gets as scared- hypothalamus start a lot of physiological reactions and prepares you to start running away
Thalamus connects to lympic directly to make the process faster ( responding with emotions )
That’s how phobias work

Question 11

two types of leearning ?

Answer 11

• Nonassociative learning
• Associative learning

Question 12

what is non associative learning ?

Answer 12

A change in behavior after repeated exposure to a stimulus

Habituation
Decreased response to a stimulus
Sensitization
Increased response to a stimulus

Question 13

Associative learning

Answer 13

• Classical conditioning
  *Instrumental conditioning

Question 14

Classical conditioning

Answer 14

Associating two stimuli (Pavlov’s dogs)

Question 16

Instrumental conditioning

Answer 16

Associating a behavior and a response

Question 17

The function of the Na+ / K+ - pump?

Answer 17

Sodium / Potassium pumpNa+ / K+ -ATPase-pump
Na+ / K+ ”exchange” pump
*
Active ion transporter, actively moves ions through the plasma membrane:
-
potassium (K+) inside the cell
- sodium (Na+) outside the cell
*
Produces an uneven distribution of Na+ and K+ ions in intracellular vs. extracellular fluids.

The Na+ / K+ -pump moves Na+ and K+ ions against their concentration gradients.
It produces and maintains transmembrane gradients for Na+ and K+ ions.

Question 17

how does short memory become long-term memory?

Answer 17

Consolidation

( Working memory –a special form of short-term memory)

Question 18

The factors that determine the resting membrane potential?

Answer 18

Resting membrane potential

At rest (no stimulation) most cells have a
negative (inside) membrane potential:
Nerve cells: -70 mV, muscle cells: -90 mV

the differences in ion concentration of the intracellular and extracellular fluids and

the relative permeabilities of the plasma membrane to different ion species.

Equilibrium potential for K+ ions (Ek) is around -100 mV
But:
RMP in neurons is -70 mV

The Nernst equation predicts the
equilibrium potential (E) for a given ion

Involvement of other ions to the RMP:
The Goldman equation

-
The RMP depends on the relative permeability of the membrane to several ions
-
However, at rest, the permeability of the membrane for Na+ ions is low, and it is high for K+ ions (PK&raquo_space; PNa)
-
Na+ ions influence the RMP to a small degree

*RMP = difference in electrical potential across the plasma membrane at rest.

*The resting membrane potential of a cell is mostly determined by the flux of K+ ions across the membrane (which is more permeable to K+ than to other ions at rest), through non-gated (leak) K+ channels. Na+ ions affect the resting membrane potential to a small extent.

*K+ ions move passively across the plasma membrane down their concentration gradient (intracellular to extracellular) taking their charge with them.

*Intracellular side of the membrane becomes more negative, extracellular positive.

*An electrical gradient is generated, opposite to the chemical gradient.

*Positive charges on extracellular side of the membrane repel K+ ions.

*At electrochemical equilibrium there is an exact balance between 2 opposing forces: 1) concentration gradient, 2) electrical gradient.

*The equilibrium potential is the electrical potential generated across the membrane at electrochemical equilibrium. It can be predicted by the Nernst equation.

*The RMP can be predicted by the Goldman equation

Question 19

The mechanisms involved in the production of action potentials?

Answer 19

*
Initial stimulus: a graded depolarization large enough to change resting potential (- 70 mV) to threshold level of voltage-gated Na+ channels (- 60 to - 55 mV)
*
Rising phase: the neuronal membrane becomes temporarily permeable to Na+ due to opening of more and more voltage-gated Na+ channels. The membrane potential depolarizes and approaches, but does not reach, ENa
*
Falling phase: Decrease in Na+ permeability (inactivation of Na+ channels) and delayed opening of voltage-gated K+ channels cause repolarization of the membrane toward EK and resting levels.
*
During the undershoot phase (afterhyperpolarization, AHP) the K+ permeability is greater than it is at rest.
*
All channels close. The membrane potential returns to resting levels.
*
All-or-none principle: If a stimulus is large enough to produce membrane depolarization to threshold, an action potential is triggered. If the membrane potential does not reach threshold, action potentials are not triggered.
*
With stronger stimulus intensities, the number of action potentials (firing frequency) increases, not their amplitude or duration.

-
Action potentials are initiated in the axon initial segment (AIS).
-
Action potentials are conducted along the axon.
-
Both AIS and axon contain voltage-gated Na+ channels and voltage-gated K+ channels.

Question 20

The structure and function of myelin in the axon?

Answer 20

Layers of lipid membrane formed by glial cells (oligodendrocytes in the central nervous system, Schwann cells in the peripheral nervous system).
- It isolates the axon and prevents the passage of current through the axonal membrane.
Conduction velocity of action potentials:
- unmyelinated axons:
0.5 to 2.0 m/sec
- myelinated axons
3 to 120 m/sec

Question 21

The different nerve fiber types and their conduction velocities?

Answer 21

motor axons fast
Sensory axons fast and slower
Autonomic preganglionic slow

in general Aa faster that Ab faster than Ac faster than Ad faster than C

Question 22

Structure and function of electrical and chemical synapses?

Answer 22

electrical =
through gap junctions

Direct physical contact between cells
*
Passive ion current flow
*
Flow of substances (e.g., ATP)
*
Bi-directional synaptic transmission
*
Fast (minimal delay)
*
Synchronization of electrical activity among neurons

chemical=
the message starts before the axon hillock
and
initial segment

▪
Synaptic transmission occurs through chemical synapses between presynaptic and postsynaptic neurons.
▪
Neurons integrate incoming information on dendrites and soma.
▪
Neurons initiate and conduct action potentials along the axon

Ca+

Question 23

The pre- and postsynaptic mechanisms of signal transmission in the chemical synapse?

Answer 23

pre- synaptic

Action potentials are conducted along the axon.
-
Both AIS and axon contain voltage-gated Na+ channels and voltage-gated K+ channels

+Saltatory action potential conduction along a myelinated axon through the nodes of ranvier

After nerve stimulation, the vesicles with the neurpthransmiter fuse together with the presynaptic membrane:
release of neurotransmitters = Exocytosis

Ca+ facilitates

post -synaptic

transmiter binds to the receptors and their channels open - then the current causes a post synaptic excitatory or inhibitory potential

Question 24

The different groups and main role of neurotransmitters?

Answer 24

1.Small molecules

oAcetylcholine: Control of movement, cognition, autonomic control

oBiogenic amines (or monoamines):
-Catecholamines:
dopamine: affect, reward, control of movement
noradrenaline(norepinephrine): affect, alertness/wakefulness, ANS
adrenaline(epinephrine): visceral functions, stress, fear
-Indoleamines: serotonin (5-HT): mood, modulation of pain, gut regulation
- Imidazoleamine: histamine: arousal, attention

oAmino acids:
-GABAand Glycine(mostly inhibitory)
-Glutamateand Aspartate(mostly excitatory)

2.Neuropeptides

-
Opioids (enkephalin, dynorphin, endorphin): Control of pain
-
Somatostatin: Endocrine functions
-
Substance P: Perception of pain, inflammation, mood

3.Others/ ” non-classical ” (non-vesicular release

-
Neuroactive gases: nitric oxide (NO), carbon monoxide (CO)
-
Endocannabinoids (anandamide)

Neurotransmitters are chemical messengers that your body can’t function without. Their job is to carry chemical signals (“messages”) from one neuron (nerve cell) to the next target cell. The next target cell can be another nerve cell, a muscle cell or a gland.

Question 25

The main classes of neurotransmitter receptors?

Answer 25

Slow synaptic transmission
*
Ionotropic receptors = Ligand-gated channels
-
Fast synaptic transmission
A neurotransmitter usually has several receptors
A neurotransmitter has both ionotropic and metabotropic receptors or only metabotropic receptors

Question 26

The different types of postsynaptic potentials and how they are generated?

Answer 26

FAST TRANSMITIONS

EPSP =
Excitatory Postsynaptic Potential

Activation of excitatory (glutamate) synapse
Glutamate is released from the presynaptic axon terminal
Glutamate binds to ionotropic receptors (AMPA and NMDA)
Na+ ions enter the cell and cause depolarization (EPSP)

IPSP =
Inhibitory Postsynaptic Potential

Activation of inhibitory (e.g., GABA) synapse
GABA is released from the presynaptic axon terminal
GABA binds to ionotropic receptors (GABAA)
Cl- ions enter the cell and cause hyperpolarization (IPSP)

Question 27

The phenomena of temporal and spatial summation?

Answer 27

Summation
of EPSPs
-
Temporal Summation:
Several times: rapid, repeated stimuli at the same synapse.
-
Spatial Summation:
Several places: many stimuli, arriving at several synapses

Question 28

The different types of modulation of synaptic transmission?

Answer 28

1.Presynaptic inhibition

GABA release from nearby neuron- inactivation of Ca+ channels - less Ca+ in presynaptic neuron - less neurotransmiter

2 .Presynaptic facilitation

Serotonin release- activation of Ca+ channels - more Ca+ - more neurotransmiter released

Question 29

The different types of synaptic plasticity?

Answer 29

Types of changes in synaptic strength:
- Synaptic Facilitation / Augmentation / Potentiation
- Synaptic Depression
Duration of the changes:
- Short-term (milliseconds to minutes)
- Long-term (hours to days or longer):
Long-term potentiation (LTP)
Long-term depression (LTD)

Question 30

EEG?

Answer 30

EEG we get electrical activity diagrams of brain regions
Age makes EEG different

Question 31

The main categories of ion channels?

Answer 31

leak chanels

Four main classes of gated ion channels
1.
Voltage-gated
2.
Chemically-gated / ligand-gated (e.g., by neurotransmitters)
3.
Mechanically-gated (stretch)
4.
Temperature-controlled (heat, cold)

Question 32

The mechanisms involved in the production of graded potentials?

Answer 32

-
Also called local potential, receptor potential, postsynaptic potential.
-
Changes in the membrane potential.
-
Amplitude is proportional to stimulus strength.
-
Spread passively in the membrane but the amplitude decreases with distance.
-
Produced by a stimulus that opens ”gated” channels

Question 33

key words
The mechanisms involved in the conduction of action potentials?

Answer 33

nodes of ranvier,voltage activated gated ion chanels
electrical and chmical synapses

Question 34

Extracellular and intracellular ion concentrations?

Answer 34

Intracellular fluid =I
Extracellular fluid=E
Potassium (K+)
High (140 mM) =I
Low (5 mM)=E
Sodium (Na+)
Low (5-15 mM)=I
High (145 mM)=E
Chloride (Cl-)
Low (4-30 mM)=I
High (110 mM)=E
Calcium (Ca2+)
Low (0.0001 mM)=I
1-2 mM=E

Question 35

Four main classes of gated ion channels:

Answer 35

1.
Voltage-gated
2.
Chemically-gated / ligand-gated (e.g., by neurotransmitters)
3.
Mechanically-gated (stretch)
4.
Temperature-controlled (heat, cold)

Question 36

what is Graded potential?

Answer 36

-
Also called local potential, receptor potential, postsynaptic potential.
-
Changes in the membrane potential.
-
Amplitude is proportional to stimulus strength.
-
Spread passively in the membrane but the amplitude decreases with distance.
-
Produced by a stimulus that opens ”gated” channels

Question 37

LTP in the hippocampus CA1early phase: induction and expression

Answer 37

Induction of LTP:
→ tetanus (rapid, intense stimulation)
→ strong postsynaptic depolarization
→ activation of NMDA receptors
→ flood of Ca2+ through NMDA receptors
→ activation of PKC and CaMKII
Expression of LTP
→ insertionofAMPA receptors at the synapse
→ strengthening of synaptic transmission (LTP)

Question 38

Threshold for action potential is ?

Answer 38

-50 to -55

Question 39

Absolute refractory period

Answer 39

= during that period a second stimulus can not activate a second action potential cause the Na+ ion gated channels are inactivated

Question 40

Why an action potential can not go the other direction ?

Answer 40

refractory period

Question 41

Explain how total body water (TKV) is normally distributed between the intracellular (ICV) and extracellular (ECV) spaces, and describe osmolarity in the ECV and ICV, under normal conditions.

Answer 41

2/3 intracelular and 1/3 extracelular

3/4 of extracellular water is intersitial and 1/4 is plasma.

Osmolarity Intracellular = Osmolarity extracellular