Exam 2: Neuron Stuctures/Functions Flashcards by Alyssa Torrez

Which ends of a neuron receive information?

Dendrites

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What is another name for the cell body?

Soma

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Is there myelination on the dendrites?

Not much if any

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Which end of a neuron sends information?

Axon

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T/F Axons are not myelinated

False

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What is the node of Ranvier?

The nodes between the myelin sheath where sodium can jump from one to another

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Is the end of the axon presynaptic or postsynaptic?

Presynaptic

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Where is the axon hillock?

The beginning part of the axon

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Which neurotransmitter is used at the axon hillock?

GABA

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What does GABA do to the cell?

Increases chloride permeability into the area of the neuron, suppressing activity or putting on the “brakes”

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What happens if we ignore GABA?

We will have over-the-top crazy levels of activity including seizures

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T/F Postsynaptic neural connections can be excitatory and inhibitory

True

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Where are excitatory neural connections found?

In areas where the dendrites are

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Are dendrites more positive or negative than the average membrane potential?

Positive

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Are inhibitory connections more positive or negative than the average membrane potential?

Negative

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What are the supporting cells of the nervous system?

Astrocytes
Ependymal Cells
Oligodendrocytes
Schwann Cells
Microglia

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Which supporting cells are the smallest?

Microglia

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What is the most abundant type of glial cell?

Astrocyte

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What do astrocytes do?

They wrap around the true part of the blood brain barrier and provide a supporting structure. Astrocytes are helpful with maintaining electrolyte balance and repairing neurons after any neuronal injury.

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Which nervous system do astrocytes support?

Central nervous system

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What are ependymal cells?

Ependymal cells contain cilia which helps produce CSF and move the CSF to ensure it circulates around the brain and spinal cord in waves

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What are microglia cells?

Microglia cells are cells that act as macrophages. They keep the area around the CNS clean and free of debris

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What are the 4 types of neurons? (Hint: Schmidt said to only worry about 3 but there’s 4 in the PPT)

Multipolar
Pseudounipolar
Bipolar
True Unipolar (NOT WORTH EXPLAINING) - not found in humans

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What are multipolar neurons?

Multipolar neurons have dendrites and connections with other parts of the CNS and play a role in decision making. They take lots of information and make a decision on whether to fire an action potential or not
Ex: Motor neurons or pain neurons that tell us to pull away from something painful

Think: decision maker

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What are bipolar neurons?

Bipolar neurons are neurons that contain 2 projections and are designed to sense and pass along information as an action potential to another area of the brain Think: Special sensory

Where do we find bipolar neurons?

Optic nerve; photoreceptors in the retina send messages through the optic nerve and create specialize senses

What are pseudounipolar neurons?

Neurons that make up the majority of sensory cells; the cell body (which mostly builds proteins and maintains things) does not make decisions and instead, it relays information from the dendrite to the axon and passes the information to the rest of the nervous system.

What are somatic sensory receptors?

Specialized structures designed to be good at sensing certain things Somatic= can consciously sense, we are aware of it Ex: Pain sensors, pressure sensors, etc.

What do free nerve endings do?

Sense Pain

What is another term for free nerve ending?

Nociceptor

Name 3 pressure sensors

Pacinian corpuscle, Meissner's corpuscle, Golgi Tendon

What is a muscle spindle?

Stretch sensor that is woven into skeletal muscle that can confirm muscle contraction

Adaptation

A sensor's ability to reset its baseline with prolonged exposure to a stimulus

Give an example of a a sensor that adapts to changing conditions

Baroreceptors readjusting to high blood pressure

What receptors undergo reverse adaptation? What does this mean?

Pain Receptors The longer the pain is sensed, the worse the pain will feel

Another word for reverse adaptation

Sensitization

Superior/ inferior

Head/ feet

Dorsal/ Ventral

Back/ Front

Anterior Posterior

Front/ Back

Medial/ Lateral

Midline/ out to the side

Rostral/ Caudal

Front and upper/ Lower and bottom Ex: on a bird the beak is Rostral and the tail is Caudal

Distal/ Proximal

Further from CNS/ Closer to CNS

Superficial/deep

How close to the skin surface

Sagittal Plane

Separates left from right

Coronal

Separates anterior from posterior

Horizontal

Separates superior from inferior ex: magician would split their assistant here

Oblique

Separates at an odd angle

Major components of the CNS

Brain Brainstem Spinal Cord

Major divisions of the brain

Telencephalon Diencephalon (Waxman Table 1-1)

Major subdivisions of the brain stem

Midbrain (mecencephalon) Pons Medulla Oblongata

Function and location of Thalamus

"Relay center" in the middle of the brain, sends info where it needs to go

Function of the hypothalamus

Sensory control Ex: temperature sensors, infection sensors

Four lobes of the brain

Frontal- thinking Occipital- visual cortex Parietal- sensory processing Temporal- auditory processing

Separates the frontal lobe from parietal lobe

Central Sulcus

Separates the temporal lobe from parietal and frontal

Temporolateral Sulcus

Runs from the front of the brain to the back of the brain and separates the left and right hemispheres

Longitudinal Fissure

Major function of the corpus callosum

-Communication between the left and right sides of the brain -highly myelinated

Part of the brain for language comprehension

-Wernicke's Area in the temporal lobe -Sensory function

Part of the brain involving word formation

-Broca's area in the frontal lobe -Motor function

Where is the primary motor cortex?

Pre Central Gyrus- Just anterior to the central sulcus (most posterior portion of frontal lobe)

Emotional centers of the brain

-Limbic System -found in various areas of the brain

Grey matter

-Contains less myelin - Decision making centers -Cell bodies make it show up darker than white matter

White matter

-Contain much more myelin - Transmitting centers

What is a benefit of having the grey matter on the superficial portion of the brain?

Close to the brain vasculature

Area in the grey matter that connects the left and right side of the spinal cord

Lamina 10

Area of the white matter that provides cross over between left and right sides of the spinal cord

Anterior White Commissure

Why is the anterior median fissure wider than the posterior?

The anterior spinal artery sits in the groove whereas the posterior does not have to make room for vasculature

What structure does CSF move down the spinal cord in?

Central Canal

Where information enters the spinal cord

-Sensory information goes into the dorsal horn (posterior) -Cell bodies here have sensory function

Where motor function leaves the spinal cord

-Ventral Horn (anterior) - Cell bodies here have motor function

What arteries supply the spinal cord arteries?

-Intercostal arteries -Feed vessels near brain stem and upper neck

How is spinal cord blood supply regulated?

Autoregulation

How are the posterior spinal arteries oriented?

To either side of the posterior, one on the left and one on the right (2 total)

When info flows into the spinal cord, how does the signal travel?

Enters horizontally through the rootlets, interacts with cell bodies in the dorsal horns (decision making area), crosses over to ascending (white) columns so it can flow up to the brain

The anterior and posterior rootlets come together to form

Anterior and posterior roots that merge into the spinal nerve

What makes the posterior root unique?

The spinal ganglion present due to collection of cell bodies (pseudo unipolar)

Where are the anterior root cell bodies?

in the ventral horn

How many cervical vertebra and corresponding spinal nerves are there?

-7 vertera - 8 sets of nerves

Where do C1 nerves exit the vertebra?

ABOVE C1 vertebra

How many thoracic vertebra and sets of spinal nerves are there?

How many lumbar vertebra and sets of spinal nerves?

How many sacral vertebra and sets of spinal nerves are there?

- At birth there are 5 separate vertebra that later fuse into 1 -5 sets of nerves

How many coccygeal nerves are there?

1 set

Dermatome

Are of the body that each spinal nerve is specialized to innervate

Lordosis

-Anterior curvature - Physiologic in cervial and lumbar spine

Kyphosis

-Posterior curvature -Physiologic in thoracic and coccyx

Scoliosis

Pathologic lateral curvature of the spine

Weight supporting structure of the spine

Vertebral body