BIOL 103 Chapter Notes - Chapter 48: Resting Potential, Axon Terminal, Axon Hillock

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4 May 2016

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Information processing occurs in 3 stages: sensory input, integration, and motor output. Peripheral nervous system: neurons that carry out information into/out of the cns. Glia: cells that produce connective tissue and organize the zones around the neurons producing myelin for some nerves. Myelin sheath: formed by glial cells and acts as an insulating material. Sensory neurons: get information from the outside world and internal conditions and is sent to the brain or ganglia. Motor neuron: sends signals away from sensory neurons for a response in muscles, long axon. Interneuron: make interconnection with other neurons, very branched dendrites, form local circuits. Most of the organelles are in the cell body. Dendrites: highly branched extensions that receive signals from other neurons. Axon: an extension that transmits signals to other cells. Axon hillock: cone shaped base of the axon and where signals that travel down the axon are generated. Synapse: space between the axon terminal and the target cell.

Related Questions

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

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

#1 Visceral sensory information enters the CNS on afferent fibers within

A) dorsal roots S_2 to S_4.

B) dorsal roots T_1 to L_2.

C) cranial nerves V, VII, IX, and X.

D) both B and C

E) A, B, and C

#2 Which of the following is not a function of the neuroglia?

A) support

B) memory

C) phagocytosis

D) secretion of cerebrospinal fluid

E) maintenance of blood-brain barrier

#3 Mary is in an automobile accident and suffers a spinal cord injury. She has lost feeling in her lower

body. Her doctor tells her that swelling is compressing a portion of her spinal cord. Which part of

her cord is likely to be compressed?

A) the anterior gray commissures

B) the anterior white commissures

C) the anterior gray horns

D) ascending tracts

E) descending tracts

#4 The efferent division of the peripheral nervous system innervates:

A) skeletal muscle cells

B) glandular cells

C) smoothmusdecells

D) heart muscle cells

E) all of the above

#5 Cerebrospinal fluid flows within the

A) pia mater.

B) dura mater.

C) filum terminale.

D) arachnoid mater.

E) subarachnoid space.

#6 A patient develops a tumor of a cranial nerve that leads to difficulty in speaking from a loss of

tongue movement.which cranial nerve is affected?

A) glossopharyngeal

B) vagus

C) spinal accessory

D) hypoglossal

E) trigeminal

#7 Parkinson disease is the result of

A) inadequate production of dopamine by substantia nigra neurons.

B) inadequate production of GABA by neurons in the basal nuclei.

C) weak response of the red nuclei of the mesencephalon.

D) decreased levels of acetylcholine from neurons in the substantia nigra.

E) hyperactivity of the limbic system.

#8 Based on the motor homunculus, which of the followingbody regions has the largest motor units?

A) larynx B) hands C) tongue D) face E) back

#9 If the corpus callosum is surgically cu!

A) conscious decisions are made without regard to sensations from the left side.

B) objects toudred by the left hand can be recognized but not verbally identified.

C) symptoms of the "disconnection syndrome" appear.

D) the two cerebral hemispheres operate independently.

E) all of the above

#10 The flexor reflex

A) moves a limb away from a painful stimulus.

B) is an example of a monosynaptic reflex.

C) prevents a musde from generating damaging tension.

D) usually depends on cranial neurons.

E) prevents a muscle from overstretching.

#11 The subdural space lies between

A) the dura mater and the arachnoid mater.

B) the arachnoid mater and the pia mater.

C) the endosteum and the periosteum.

D) the pia mater and the dura mater.

E) the pia mater and the subarachnoid space.

#12 _____ is a condition resulting from an inflammation of a facial nerve.

A) Cerebral palsy

B) Addison disease

C) Bell palsy

D) any of the

#12 Clusters of RER and free ribosomes in neurons are called

A) microglia.

B) neurofilaments.

C) neurofibrils.

D) Nisslbodies.

E) perikaryon.

BIOL 103 Chapter Notes - Chapter 48: Resting Potential, Axon Terminal, Axon Hillock

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