CAS BI 315 Lecture Notes - Lecture 6: Nernst Equation, Exocytosis, Efferent Nerve Fiber

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1 Jun 2018

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Membrane and Action Potentials

I. Neurons

A. has 5,000-50,000 dendrites

B. Every axon terminal can connect to other cells

1. More terminals = more connections

C. Efficient communication over short or long distances

D. Electrical signals within neuron

E. Chemical signals between

F. Neuron = single nerve cell = nerve fiber

G. Nerve = collection of axons outside of brain/spinal cord

H. dendrites/cell boddy receive info (signals/stimuli)

I. Transmit electrical signal along axon, reaches end of acon, triggers release of

chemical (neurotransmitter/NT) -- communicates with another neuron or muscle

cell

II. Neuron function

A. Neurons connect brain to organs, skin, muscles

B. Only send signals in 1 direction, electrical signals within, protein signals between

C. Sensory neuron → interneuron → efferent neuron

III. Glial Cells

A. 9 types of cells

B. “Glue” - not true has roles

C. Mice in maze study - mice with human glial cells figure out maze and decrease

anxious behavior faster

IV. Electricity

A. Movement of ions

B. If we can separate + and - charges, we can generate electricity

C. Na+/K+ pump and membrane

D. Core concepts

1. Opp attract, like repel

2. Electrical difference btw 2 pts = potential to do work aka potential energy

3. Resistance = barriers to flow

4. Movement of ions = current

V. Ohm’s Law

A. I=V/R

B. Current = voltage/resistance

C. Current proportional to voltage bc more movement if greater diff btw 2 places

D. I inverse to resistance bc current slower if more resistance

VI. Inside cell

A. Lots of phosphorylated groups = net - charge

1. Lots of potassium

B. Extracellular = mixed

C. Neuron rest = 70 mV

VII. Charge separation

A. Equilibrium refers to concentration

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Document Summary

Neuron function: neurons connect brain to organs, skin, muscles, only send signals in 1 direction, electrical signals within, protein signals between, sensory neuron interneuron efferent neuron. Glial cells: 9 types of cells, glue - not true has roles, mice in maze study - mice with human glial cells figure out maze and decrease anxious behavior faster. Inside cell: lots of phosphorylated groups = net - charge, lots of potassium, extracellular = mixed, neuron rest = 70 mv. Charge separation: equilibrium refers to concentration, polarized = charge, hyperpolarized = more neg inside, more pos outside. Nernst equation: eion = (61/z) log (cout/cin, goldman-hodgkin-katz equation, takes into account individual ion permeabilities (p, k+ has leak channels = rmp closer to ep k+ than ep na+ Rmp summary: due to na+/k= pump, closer to ep k= bc leak channels. Gated channels: mechanically and chemically gated create small depolarizing events, voltage gated responds to voltage change and allow massive depolarization.

Related Questions

Nerve cells that conduct messages are called (1) ____. (2) _____ cells, which support and nurture the activities of neurons, make up less than half the volume of the nervous system. (3) _______ neurons respond to specific kinds of environmental stimuli, (4) ______ connect different neurons in the spinal cord and brain, and (5) ______ neurons are linked with muscles or glands. All neurons have a (6) _______ ________ that contains the nucleus and the metabolic means to carry out protein synthesis. (7) _______ are short, slender extensions of the (6), and together these two neuronal parts are the neuronsâ âinput zoneâ for receiving (8) _____. The (9) _____ is a single long, cylindrical extension away form the (10) ______; in motor neurons, the (11) ______ has finely branched (12) ________ that terminate on muscle or gland cells and are âoutput zones,â where messages are sent on to other cells. A neuron at rest establishes unequal electric charges across its plasma membrane, and a(n) (13) ____ ____ is maintained. Another name for (13) is the (14) _____ _____ _____; it represents an ability for the membrane to be disturbed. Weak disturbances of the neuronal membrane might set off only slight changes across a small patch, but strong disturbances can cause a(n) (15) _______ ______, which is an abrupt, short-lived reversal in the polarity of charge across the plasma membrane of the neuron. For a fraction of a second, the cytoplasmic side of a bit of membrane becomes positive with respect to the outside. The (16) ______ that travels along the neural membrane is nothing more than short-lived changes in the membrane potential. A. Neurons H. Sensory B. Motor I. Endings C. Interneurons J. Disturbance D. Cell body K. Signals (stimuli) E. Axon L. Voltage differential F. Dendrites M. Resting membrane potential G. Neuroglial N. Action potential

azureelk922

Which of the following statements is TRUE regarding sea anemones?

	None of the answer options is correct.
	Spongesânot sea anemonesâpossess what is considered to be the âsimplestâ nervous system found in animals.
	Because sea anemones are âsimpleâ organisms, these animals only possess motor neurons; sensory neurons or interneurons are never found in sea anemones.
	Although sea anemones possess ânet-likeâ nervous systems, these animals have brains located at their bases (near where they would attach to rocks).
	Although sea anemones lack definitive brains, they do possess ganglia that serve a similar function to the paired ganglia of flatworms.

Some people have low levels of calcium circulating in the blood, a condition known as hypocalcemia. While for many this disorder has little to no effect, for some it can be life-threatening. How could low levels of calcium harm an individual?

	Low levels of calcium would not have any effect on synaptic transmission.
	Low levels of calcium would cause sustained depolarization of the presynaptic cell.
	Low levels of calcium would result in fewer signals sent between the pre- and postsynaptic cell.

Cephalization is: the

	All of these choices are correct.
	development of a brain within the head of an animal.
	concentration of sensory organs within the head end of an animal.
	development of a âhead endâ in an organism.

Which of the following are TRUE about the resting membrane potential? (Select all that apply.)

	It results from voltage-gated sodium channels remaining open for long periods of time.
	It results from K⁺ ions diffusing out of the cell.
	It results from the sodium-potassium pump moving more Na⁺ ions out of the cell than K⁺ ions into the cell.

Afferent and efferent neurons differ in:

	their size.
	the directionality of the information they send.
	their pattern of myelination.

A neuron that responds to the environment is a(n):

	interneuron.
	homeostatic neuron.
	motor neuron.
	sensory neuron.

Which of the following is NOT the role of an interneuron?

	stimulating a muscle to contract
	conveying information from the internal environment of an animal
	relaying information from sensory to motor neurons
	maintaining homeostasis

Where are postsynaptic cell receptor proteins synthesized?

	the Golgi apparatus
	the lysosome
	the cytoplasm
	the rough endoplasmic reticulum

Inhibition of the flexor muscle during the knee-extension reflex is an example of:

	homeostasis.
	reciprocal inhibition.
	negative feedback.
	All of these choices are correct.

10.

What type of cells produce myelin for sensory neurons?

	pyramidal neurons
	glial cells
	melanocytes
	astrocytes

CAS BI 315 Lecture Notes - Lecture 6: Nernst Equation, Exocytosis, Efferent Nerve Fiber

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