More on Membrane Potentials, Intro to Nervous System, Central Nervous System

What structure does the hypothalamus interact with which controls emotions and drives?

Amygdala

What are the four structures of the limbic system?

Amygdala Hippocampus Thalamus Cingulate gyrus

What are the eight functions of the hypothalamus?

1. Activation of sympathetic nervous system. 2. Maintenance of body temperature. 3. Control of body osmolarity. 4. Control of reproductive functions. 5. Control of food intake. 6. Interacts with limbic system to influence behavior and emotions. 7. Influences cardiovascular control center in medulla oblangata. 8. Secretes trophic hormones that control release of hormones from anterior pituitary gland.

Action potentials in motor neurons are conducted from ________________________ to ________________________. This is called the ________________path.

Action potentials in motor neurons are conducted from cell body to axon terminals. This is called the efferent path.

What are the functions of the amygdala and what system is it part of?

Emotion and memory; limbic system

What do the nodes of Ravier allow?

For an ion flow to jump from node to node.

In what case will the EEG not show synchronized pattern of waves?

If the corpus callosum is damaged.

Review the major anatomical and functional areas of the cerebral cortex.

In progress

What is important for long term memory?

Increased protein synthesis.

What are the functions of the hippocampus and what system is it a part of?

Learning and memory; limbic system

What is the function of the hippocampus?

Memory consolidation.

What are the functions of the structures of the brain stem? Page 301

Midbrain - eye movement Pons - relay station between the cerebrum and the cerebellum & coordination of breathing Medulla oblangata - the central control centers for cardiovascular and respiratory function are in this area Diffuse group of neurons of the reticular formation found in the diencephalon, pons, and medulla oblangata - involuntary control of skeletal muscles, arousal (alertness), sleep, and pain modulation

Which demyelinating disease is of the CNS?

Multiple sclerosis

What type of mechanisms affect receptors or receptor signal transduction?

Postsynaptic

What type of mechanism affects neurotransmitter release?

Presynaptic

List the embryonic divisions of the brain and the adult derivatives of the hindbrain. Slide 38 Primary Division > Subdivisions > Major Derivatives Format

Rhombencephalon (hindbrain) > Metencephalon & Myelencephalon > Metencephalon (cerebellum, pons) & Myelencephalon (medulla oblangata)

What side of the brain is responsible for spatial visualization and analysis?

Right side.

Locate the following structures: cerebrum, corpus callosum, thalamus, hypothalamus, diencephalon, pituitary, brainstem: midbrain-pons-medulla, and cerebellum.

Slide 42

What does spatial summation of graded potential mean?

The signals arrive simultaneously at different locations on the neuron to initiate an action potential.

Membrane Potential/Membrane Voltage

Voltage across a membrane due to charge imbalance.

What are the two types of neural pathways?

diverging and converging

What is gray matter consisted of in a cross section of the spinal cord?

mostly cell bodies of neurons

What does the diencephalon consist of that are usually considered part of the brain stem? Slide 42

thalamus & hypothalamus

*How do action potentials differ from graded potentials?

*Graded potentials are small changes in either + or - Em, whereas action potentials are large changes.

Slide 13 - More on membrane potentials: What is the concentration of K+ inside and outside the cell and what direction will K+ move if a K+ channel opens?

*a 0mV means weak EMF, so K+ is probably equal on both sides of the membrane since the EMF is weak.

If the membrane potential is - 90 mV and the E sodium is + 55, the EMF for sodium is what? Interpret the value.

-145 mV. This is a strong electromotive force to drive sodium into the cell if sodium channels are open.

*If three sodium ions leave the cell, two potassium ions enter the cell, and two anions are synthesized inside the cell, what is the membrane potential inside the cell?

-3

Name the basal nuclei surrounding the thalamus that are important in the control of movement. Slide 40

1. Caudate nucleus 2. Putamen 3. Globus pallidus 4. substantia nigra 5. subthalamus

Name three characteristics of action potentials of nerve impulses. Slide 17.

1. Depend on a threshold change in EM. The ion channels are voltage sensitive. 2. Action potentials are all or none. If stimuli is smaller than threshold, then you get no action potential. If stimuli is more than threshold, you still get the same size action potential because the action potential size does not change. 3. Action potentials exhibit a refractory period.

What factors maintain the net negative charge inside cells at rest?

1. Leaky K+ channels 2. Largely negatively charges proteins inside the cell (anions) 3. Sodium Potassium Pump

Increased protein synthesis can have tw0 effects discussed on slide 49. What are they?

1. May involve synthesis of additional neurotransmitter receptors or ion channels. 2. They may uncover masked receptors.

Describe the ion changes before, during, and after an action potential. Slide 15

1. The mammalian neuron is stimulated which causes the sodium channels to open. 2. Sodium ions rush into the cell because the large chemical gradient - high to low. This causes depolarization at the point where sodium entered. 3. If the Em reaches threshold voltage, the potassium channels open. 4. Potassium rushes out of the cell, leaving behind a - charge, so the cell has repolarized now - which means returning to a negative Em. 5. Potassium channels do not close until after the membrane potential is more negative than the resting voltage = hyperpolarization.

What are the symptoms of aphasia?

1. Trouble speaking 2. Struggling with finding the appropriate term or word 3. Using strange or inappropriate words in conversation

When is the speed of action potentials increased?

1. in larger diameter axons due to decreased resistance to current flow. 2. if myelin is present.

What are the four classes of glutamate receptors? Note which ones are the ligand-gated ion channels.

1. metabotropic glutamate receptor 2. NMDA receptor 3. KA receptor 4. AMPA receptor

Name all the postsynaptic mechanisms. Slide 24

1. transmitter binds to receptor on postsynaptic cell 2. transmitter + receptor either opens or closes ion channels OR acts via second messengers to open for another neuron and the entire process repeats. (Either step 2 or 3 happens, not both.) 3. OR termination of transmission by either degradation of transmitter or reuptake of transmitter into presynaptic cell.

Name all the presynpatic mechanisms. Slide 24

1. transmitter synthesis 2. transmitter storage in vesicles in nerve terminals 3. action potential 4. opening of calcium channels in the nerve terminal 5. extracellular calcium enters the nerve terminal 6. calcium stimulates release of vesicles containing neurotransmitter.

Define hyperpolarization.

A change in the potential that is more negative than the resting potential.

Define action potential.

A positive change in voltage (depolarization) that is propagated along the membrane and does not diminish as it travels along nerve fibers.

Which neurotransmitter is of all somatic nerves innervating skeletal muscles and all parasympathetic nerves innervating organs?

Acetylcholine

With anatomical feature is responsible for sensory information from the periphery to the brain? Give both names.

Afferent Tract/ Asscending Tract

What two things does the amount of voltage change depend on?

Amount of stimulation (depolarization) or inhibition (hyper-polarization).

What is the difference between anterograde and retrograde?

Anterograde refers to transport within axon away from cell body, and retrograde means transport within axon towards the cell body.

What type of neuron is dominant for smell and vision?

Bipolar neurons.

Why can't dopamine enter the brain if it is injected into the blood?

Blood brain barrier

What structure is responsible for the motor aspects of language, such as speaking?

Broca's area

How is a long-term potentiation initiated?

By high frequency stimulation or tetanic stimulation (repeating stimulation) of a presynaptic neuron.

Know the anatomy of a spinal cord. Slide 33

Cranium Cerebral hemispheres Cerebellum Cervical spinal nerves Thoracic spinal nerves Lumbar spinal nerves Sacral spinal nerves Coccygeal nerve

What is the function of the amygdala?

Creating emotions and formation of memory.

What does this mean: cerebral lateralization = cerebral dominance?

Depending on the side of the brain that your body prefers, the more dominant it is relative to the other side.

If you shift the potential from a negative voltage to a less negative voltage (closer to zero or to a positive voltage, is this hyperpolarization of depolarization?

Depolarization

Define aphasia.

Disorders of language.

Differentiate dorsal from ventral.

Dorsal is the back side, and ventral is the belly side.

Write out the Nernst Equation.

E ion = 58/z x log10 ([ion]out/[ion]in)

Describe the EEG.

EEG stands for electroencephalogram. It provides an index of alertness and sleep.

At rest the permeability of K+ greatly exceeds that of other ions, and Em can be reduced to what equation?

EK+ = 58 x log10 ([K+]out/[K+])in.

What is the EMF formula?

EMF = Em - Eion EMF of the ion = the resting membrane potential - the equilibrium potential of the ion.

With anatomical feature is responsible for motor information from the brain to the periphery? Give both names.

Efferent Tract/ Descending Tract

What is the difference between efferent and afferent?

Efferent means away from cell body or away from the brain (motor), and afferent means toward the cell body or toward the brain (sensory).

Write out the Goldman-Hodgkin-Katz Equation.

Em = RT/zF x loge [ (PK+)([K+]out/[K+]in) + (PNa+)([Na+]out/[Na+]in) + (PCl-)([CL-]in/[Cl-]out) ]

Define EPSP.

Excitatory postsynaptic potential - a small positive change in Em (a small depolarization).

In neurons, the regions of fibers are equally sensitive to depolarization. T/F

F. Certain regions are more sensitive than others.

In action potential of neurons, current can only spread in one direction. T/F

F. They can spread in both directions.

Small myelinated axons may conduct impulses slower than large myelinated axons. T/F

F. They may conduct impulses equally. One compensates for the other.

Postsynaptic inhibition deceases neurotransmitter release. T/F

False.

Presynaptic inhibition decreases receptor number or transduction. T/F

False.

What is the major inhibitory transmitter?

GABA - gamma amino butyric acid

What is gray matter and white matter?

Gray refers to the dark color which indicates the presence of cell bodies. White matter refers to the lighter shade which indicates the presence of fibers in the brain.

Which demyelinating disease is of the peripheral nervous system?

Guillain-Barre

What brain structure is responsible for controlling the drives for thirst, hunger, sex, and osmolarity?

Hypothalamus

What structure of the brain is the satiety center and feeding center?

Hypothalamus

Describe ion currents (movement of ions in specific directions) that can cause EPSPs or IPSPs.

I dont know.

*If ATP-gated K+ channels close, how does it affect the voltage gated Ca++ channels?

In the resting cell, leaky potassium channels are open because there is less ATP. Once more intracellular ATP is produced by eating a meal, the K+ channel closes which causes the positive retention and depolarization of the cell. This causes the voltage sensitive Ca2+ channels to open because they move down their electrochemical gradient.

Define IPSP.

Inhibitory postsynaptic potential - a small negative change in Em (a small hyper-polarization).

The recording electrode is inside the cell; therefore the negative or positive membrane potential refers to the net +/- voltage _____________ the cell.

Inside

____________ flow across the membrane causes IPSPs or EPSPs.

Ion flow.

What effect does increasing the size of the stimulus have on the graded potential?

It increases the size of the graded potential.

If the membrane potential is - 90 mV, and the E potassium is -90 mV, the EMF for potassium will = - 90 mV - (-90) mV = 0 . Interpret the calculated EMF

It is a weak EMF, but a concentration gradient could still drive K+ across the cell membrane.

Define depolarization.

It is the change in the potential in the positive direction.

Define relative refractory period.

It is the time after the action potential when the threshold voltage is increased above the usual level.

Define absolute refractory period.

It is the time during and after the action potential when another action potential cannot be stimulated.

What happens if high frequency stimulation of a presynaptic neuron happens?What is the term that describes this phenomenon?

It results in prolonged depolarization of a postsynaptic neuron. Long-tern potentiation.

If the person is right-handed, what is the dominant hemisphere of the brain?

Left side of the brain.

What side of the brain is responsible for writing and the speech center?

Left side.

What is the function of the hypothalamic SCN?

Master rhythm generator.

What is the difference between membrane potential and equilibrium potential?

Membrane potential represents a net voltage with the presence of a net flux of the ion across the membrane, where as, equilibrium potential represents the presence of NO net flux of the ion across the membrane.

List the embryonic divisions of the brain and the adult derivatives of the midbrain. Slide 38 Primary Division > Subdivisions > Major Derivatives Format

Mesencephalon (midbrain) > Mesencephalon > No Major Derivatives

Most infants with ONH (optic nerve hypoplasia) have involuntary, rapid eye movements (nystagmus) and/or mild to severe visual impairment of one or both eyes. Vision often improves modestly in early childhood even though there is no growth of the optic nerves after birth. What part of the brain can cause the rapid eye movement which is a common symptom for infants with ONH?

Midbrain abnormalities can cause rapid eye movement in infants with ONH.

What are the functions of the cerebellum?

Movement coordination

What can compensate for a small axon diameter.

Myelin

When a positive ion leaves the cell, what type of charge is left behind inside the cell?

Negative

Does it action potential travel along the least sensitive areas of the nerve fibers?

No. It travels along the most sensitive areas, usually in one direction.

Define saltatory conduction.

Node to node current flow.

Which neurotransmitter is of sympathetic nerves and affects 4-5 different types of adrenergic receptors (alpha 1, alpha 2, beta 1, beta 2, beta 3)?

Norepinephrine

Which glia are central and note whether each produces myelin or not?

Oligodendrocytes - produce myelin Astrocytes Microglia Ependymal cells

What is metabotropic?

One of the four classes of glutamate receptor.

Which well known diseases result from abnormal function of one or more of the basal ganglia?

Parkinson's & Huntington's

Melatonin naturally occurs in the body, and it is even found as an OTC supplement in many drug stores. Which structure is responsible for melatonin secretion?

Pineal gland

At the point of entry, what is the charge inside the cell if a positive charge enters the cell?

Positive

Be able to draw slide on "organization of nervous system."

Ppt. MembPotentialsContd+IntroNeuro2017, slide 8.

List the embryonic divisions of the brain and the adult derivatives of the forebrain. Slide 38 Primary Division > Subdivisions > Major Derivatives Format

Prosencephalon (forebrain) > Telencephalon & Diencephalon > Telencephalon (cerebral cortex, basal ganglia, limbic system) & Diencephalon (thalamus, hypothalamus, pineal gland)

What does R, T, z, and F in the Nernst equation represent?

R = gas law constant 8.314 J/K mol T = absolute temperature 298K z = ion's valence F = Faraday constant 96485 s A/ mol

What structure is important in regulating the balance between sleep and arousal (alertness)?

Reticular formation - the multiple nuclei found in several thalamic and brainstem areas. The hypothalamus also contributes to the intensity of arousal.

Which glia are peripheral and note whether each produces myelin or not?

Satellite cells Schwann cells - produce myelin

Know graph on slide 16.

See ppt.

What are the functions of the cerebral cortex?

Sensory areas-perception Motor areas - skeletal muscle movement Association areas - integration of information and direction of voluntary movement

*How would hyperpolarization affect the chance of triggering an action potential?

Since hyperpolarization is a change in the negative direction, the action potential would be more difficult to trigger since the threshold has to be positive.

Be able to visually differentiate ascending tracts from descending tracts.

Slide 35

Locate the following structures: somatic sensory nuclei, visceral sensory nuclei, autonomic efferent nuclei, somatic motor efferent nuclei.

Slide 36 - Label the colored parts. ignore the other parts with numbers.

What are graded potentials?

Small changes in membrane voltage.

Describe how anatomists differ on what the brainstem consists of. Slide 40

Some physiologists refer to the brainstem as the midbrain, pons, and medulla oblangata. But anatomists usually refer to the brainstem as all of the brain areas left when the cerebellum and cerebral hemispheres are removed.

What structures are part of the diencephalon?

Thalamus Pineal gland Hypothalamus Pituitary gland

What are the functions of the structures of the diencephalon? Page. 300

Thalamus - integrating center and relay station for sensory and motor information Pineal gland - melatonin secretion Hypothalamus - homeostasis and behaviorial drives Pituitary gland - hormone secretion

What does the reduced equation of Em mean?

That the resting membrane potential of most cells will be close to the equilibrium potential of K+.

In order to open the potassium channel, you have to reach a positive threshold voltage. What needs to happen in order for the potassium channel to close?

The cell must hyperpolarize - the membrane potential must be more negative than the resting voltage.

Define electromotive force.

The driving force that causes flow of a specific ion.

What does the P in the Goldman-Hodgkin-Katz Equation represent?

The permeability coefficient of each ion.

What charge is the resting membrane potential of cells and why?

The resting membrane potential of cells is negative and is due to: 1. Sodium/potassium pump 2. Diffusion of potassium through leaky K+ channels 3. Large negatively charges proteins in cells (large anions)

What does the total sum of all IPSPs and EPSPs determine?

The sum determines whether a stimulus is sufficient to generate an action potential or the membrane is hyperpolarized by inhibitors.

Differentiate between the terms nucleus and ganglion.

The term nucleus usually is used for a group of cell bodies in the brain, and the term ganglion is used for a group of cell bodies in the periphery.

*What does "net flux of the ion" mean?

The voltage that balances the ion's concentration gradient.

Define ionotropic receptors.

They are neurotransmitter receptors hat are either ligand-gated ion channels or directly linked to ion channels.

What effects on language would you expect to observe in patients with damage to Wernicke's, to Broca's, or to the comparable areas in the non-dominant hemisphere?

They can not understand nor physically produce verbal language.

What feature do capillaries in the brain have that makes them less permeable than most capillaries of the body? What do these not so permeable capillaries form that prevents substances from entering the brain?

Tight junctions, blood brain barrier

What is the purpose of the Goldman-Hodgkin-Katz Equation?

To calculate the resting membrane potential which theoretically depends on the concentration of diffusable (permeable) ions.

T/F. Converging pathways do not help the brain with locating pain.

True.

What are the two main types of neurons and what is the difference between them?

Unipolar has only one extension from the cell body, whereas, bipolar has two extensions from the cell body.

Describe the pathway of information comprehension and then being able to verbalize it.

Visual cortex > Wernicke's areas > Broca's area > Motor cortex.

What structure is responsible for comprehension?

Wernicke's area

What does temporal summation of graded potentials mean?

When a signal is rapidly repeated (high frequency stimulation) at the same location, the graded potentials add up (summate).

When is an action potential triggered?

When the membrane potential depolarizes to a positive threshold voltage (approximatesly +45 mV in some neurons but threshold can vary in different cells.)

The second action potential is different from the first action potential because _______________________________________________________?

a larger than threshold stimulus is required to stimulate a second action potential.

Non-dominant hemisphere controls the ____________________ aspects of language.

affective (emotional)

What is basal ganglia?

basal nuclei of the brain

What is white matter consisted of in a cross section of the spinal cord?

bundles of axons known as tracts

What structure is responsible for secreting CSF? Where does it secrete CSF into?

choroid plexus, subarachnoid space surrounding the brain and spinal cord

Where does all sensory information entering the spinal cord enter? Locate the structure.

dorsal horns

Where are the cell bodies of all peripheral sensory neurons located? Locate the structure.

dorsal root ganglion

What structure brings all the sensory information into the spinal cord?

dorsal root neurons

The dominant hemisphere has the ____________________ centers.

language

The blood brain barrier does not exclude what type of molecules? They are able to pass directly through membranes.

lipid soluble molecules

What are the functions of the basal ganglia?

movement

Which major type of cholinergic receptors that acetylcholine acts upon are linked to second messenger systems?

muscarinic receptors

Learning and memory often involve facilitation of ___________________________ and _______________..

neural connections and pathways

Which major type of cholinergic receptors that acetylcholine acts upon is ionotropic?

nicotinic receptors

Name the two major types of cholinergic receptors that acetylcholine acts upon.

nicotinic receptors and muscarinic receptors

What anatomical feature in neurons interrupts myelin?

nodes of Ranvier

What is ganglion/ganglia?

nucleus/nuclei in neurons

Stimulation and conduction of an action potential in a sensory neuron is conducted from _____________________ to ________________. This is know as the ___________________ path.

receptor, cell body, afferent path

What specific activity does the EEG pattern show?

synchronized neural activity

What is the function of the choroid plexus?

transport ions and nutrients from the blood into the CSF.

What structure contains the cell bodies of ventral horn neurons that innervate all skeletal muscles? Locate the structure.

ventral horns