Anat 1 - Ch. 11 Neural Tissue

Provides swift, brief responses to external stimuli (by receiving and analyzing sensory input); tells effectors when to respond (sends motor signals to muscles and glands); maintains homeostasis (controls internal environment of body); and makes you, YOU (includes thought, learning, emotion, memory, and imagination)

Discuss the major functions/purposes of the nervous system.

Neurons

The cells of the nervous system

Nerves

A group of neurons

Neuroglia

Support cells of the nervous system

Brain and spinal cord

What are the organs of the CNS (Central Nervous System)?

Cranial nerves and spinal nerves

What are the two groups of nerves found in the PNS (Peripheral Nervous System)?

12

How many cranial nerves are there?

31

How many spinal nerves are there?

sensory

Nervous system afferents are _______ neurons

motor

Nervous system efferent are ______ neurons

These are the tiny neurons inside the CNS that connect everything

What is an interneuron?

skin, joints, skeletal muscles

Somatic afferents carry info from _______ ______ ___________ to CNS?

cardiac and smooth

Autonomic efferents carry info from CNS to ____ and ________ muscles and glands

Astrocytes, Microglia, Ependymal cells, and Oligodendrocytes

Name the 4 neuroglia of the CNS

Schwann cells and satellite cells

Name the 2 neuroglia of the PNS

Make the blood brain barrier

What is the function of astrocytes?

Act as phagocytes to remove debris

What is the function of microglia?

Make the cerebrospinal fluid (CSF)

What is the function of ependymal cells?

Myelinate axons of neurons in CNS

What is the function of oligodendrocytes?

Myelinate axons of neurons in PNS

What is the function of Schwann cells?

Support and protect cell body of PNS neurons

What is the function of satellite cells?

Multiple Sclerosis

Name a demyelinating disease of CNS?

Pick up data and bring into cell body

What is the function of the dendrites?

Send action potential

What is the function of the axon?

Dendrites

Label 1

Axon

Label 2

Node of ranvier

Label 3

Axon terminal

Label 4

Myelin sheath

Label 5

Cell body

Label 6

Nucleus

Label 7

Rough ER

What would a Nissl’s body be called in a non-neuron cell?

Where the axon meets the cell body

What is the axon hillock?

NO

Are dendrites or cell body ever myelinated?

Axon only

Which part of a neuron may be myelinated?

Speeds up transmission of action potential

What is the function of a myelin sheath?

Schwann cells

Which cells create myelin in the PNS?

Oligodendrocytes

Which cells create myelin in the CNS?

Gaps in the myelin sheath

What is a Node of Ranvier?

No

Can neurons divide by mitosis?

Unmyelinated

Is grey matter myelinated or unmyelinated?

Myelinated

Is white matter myelinated or unmyelinated?

Anterograde

Transport of substances in microtubules from cell body to axon terminals is called __________ transport

Retrograde

Transport of substances in microtubules from axon terminals back to cell body is called _____ transport

Neurotransmitters

What kinds of things would be sent to the axon terminals by anterograde transport?

Waste products and bits of neurotransmitters for recycling

What kinds of things would be sent to the cell body by retrograde transport?

Has two processes coming out of cell body

Describe a bipolar neuron

Has only 1 process coming out of cell body

Describe a Unipolar neuron

Has many processes coming out of cell body

Describe a multipolar neuron

Pseudounipolar

Sensory neurons are usually from which structural classification?

Multipolar

Motor neurons and interneurons are usually from which structural classification?

In retina and nose, special senses only

Where are bipolar neurons found?

Inside

Is the cell body of a multipolar neuron found inside or outside the CNS?

In a ganglion, outside the brain or spinal cord

Where is the cell body of a Unipolar sensory neuron found?

Nucleus

A cluster of cell bodies in the CNS is called

Ganglion

A cluster of cell bodies in the PNS is called

Nerve

A group of axons in the PNS is called

Tract

A group of axons in the CNS is called

No, short

Do graded potentials last long?

Yes

Do graded potentials fizzle out?

action potentials

Graded potentials, if large enough, turn into

Stronger stimulus, open more ion channels, make a bigger depolarization to hit threshold

How could you make a bigger graded potential?

Depolarize

If you open Na+ channels, will the membrane depolarize or hyperpolarize?

Hyperpolarize

If you open K+ or Cl- channels, will the membrane depolarize or hyperpolarize?

Axon hillock

Know which part of a neuron generates action potentials

Axon only

Which part of the neuron generates action potentials?

No

Do action potentials ever fizzle out?

The depolarization level you have to hit for a graded potential to turn into an action potential

What is a “threshold”

Axon hillock

Where do action potentials start in neuron?

Depolarization

Voltage gated Na+ channels open and Na+ rushes in, becomes less negative

Repolarization

Na+ channels inactivated, K+ channels open, K+ rushes out

Hyperpolarization

Na+ channels closed, K+ channels closing slowly

K+ closed and Na+ closed

Resting State

K+ closed and Na+ open

Depolarization

K+ open, Na+ inactivate

Repolarization

K+ closed slowly; Na+ closed

Hyperpolarization

Graded potential: Magnitude varies with stimulus strength, fizzles out, occurs in dendrites and cell bodies

Action potential: All or none, doesn’t fizzle out, only occurs in axons

What are the differences between Graded Potentials and Action potentials?

You recreate the same thing over and over again; you can recreate the action potential at each node so it can’t fizzle out

What does “propagation” mean and how is it different to conduction?

Refractory period

What keeps the action potential heading the right way down the neuron?

Yes, always -70mV to +30mV

Is every action potential of the same magnitude?

Send more action potentials more often

If every action potential is the same, how do you show that one message is more important than another?

Unmyelinated (slow)

What type of neuron does continuous propagation: myelinated or unmyelinated?

Myelinated (fast)

What type of neuron does salutatory propagation: myelinated or unmyelinated?

fast, big, and myelinated

Group A neurons are ______, _______, ________

medium

Group B neurons are ________

slow, small, and unmyelinated

Group C neurons are _______, ____________, __________

Oligodendrocytes

Which cells are affected by multiple sclerosis?

Autoimmune disease

The immune system is attacking our own cells in multiple sclerosis. What is the term for these types of diseases where the immune system attacks our own cells?

Disrupted brain to body communication

What is the consequence of damage to the myelin sheath of CNS neurons?

Pre-synaptic

Which neuron sends the message?

Post-synaptic

Which neuron receives the message?

Pre-synaptic

Which neuron releases the neurotransmitter?

Post-synaptic

Which neuron has the receptors to bind the neurotransmitter?

Electrical

Which synapse sends messages faster?

Electrical

Which synapse has no synaptic gap?

Electrical

Which synapse has gap junctions?

Chemical

Which synapse has chemical neurotransmitters?

Chemical

Which is the most common kind of synapse?

Break down with enzyme, reuptake, float away

Describe the three possible fates of neurotransmitters after the signal has been sent.

Excitatory postsynaptic potential

What does EPSP stand for?