OPT 113 Neuroanatomy Midterm 1

pertaining to, located toward the head

cranial

pertaining to, or located toward the tail

caudal

What is the basic unit of the nervous system?

neuron

What are the three parts of a neuron?

cell body, dendrites, axon

What is a group of a lot axons in a cable like structure called?

nerve

PNS structure that contains a lot of cell bodies of neurons

ganglion

CNS structure that contains the collection of cell bodies of neurons

nucleus

Anterior portion of brain

rostral

Posterior (towards tail) of brain

caudal

Nerves that receive and transmit information from the environment to the CNS

Afferent (sensory)

Nerves that transmit information generated in the CNS to the peripheral

Efferent (motor)

What are the two main parts of the nervous system?

-Central nervous system
-Peripheral nervous system

Central nervous system is comprised of:

brain and spinal cord

What type of nerve are spinal nerves?

Motor nerves

What is the Peripheral nervous system comprised of?

-cranial nerves (not CN I or II)
-spinal nerves
-peripheral nerves
-neuromuscular junctions

What type of nerves are peripheral nerves?

mixed

What are the functional divisions of the PNS?

somatic nervous system and autonomic nervous system

What does the somatic nervous system do?

controls conscious and voluntary movements

What does the autonomic nervous system do?

involuntary actions

What can the autonomic nervous system be subdivided into?

Sympathetic and parasympathetic

What are the somatic PNS effectors?

Skeletal muscle

What are the autonomic PNS effectors?

Smooth muscle, cardiac muscle, sweat glands, tear glands, adrenal glands, adipocytes

Found in both CNS and PNS and transmit information via electrical or chemical signals

Neurons

Found in the CNS and support neurons and their functions

glial cells/neuroglia

What are the different types of glial cells in the CNS?

astrocytes, microglial cells (microglia), ependymal cells (ependyma), oligodendrocyte

What are the cells within the PNS that produce myelin and wrap around axons of a neuron?

Schwann cells

What are other names for the cell body of a neuron?

Perikaryon/soma

What is located within a cell body of a neuron?

Nucleus, organelles, cytoplasm

Part of neuron that receives the signal (also can receive multiple signals)

dendrites

Part of neuron where the signal is transmitted (sends signal)

axon

Since there are multiple dendrites that can receive multiple signals, where in the neuron do all of this signals come together to create a net signal?

axon hillock

What is the dendrite + axon structure called?

neurite

Utilizes protein kinesin: transport secretory vesicles and mitochondria

walks down the "track" in the axon; uses ATP

Rapid anterograde

"Axoplasmic flow"

a slow process that carries newly synthesized proteins from the cell body to the axon terminals

Utilizes protein dyenin: transport worn-out organelle

Rapid Retrograde

Motor protein needs ATP to move vesicle to axon termination and need it very quickly (usually neurotransmitter or mitochondria)

Rapid anterograde

anterograde; doesn't need ATP; used to transport proteins and structural filaments for use in axon

Slow transport

Organelles that make it to the axon terminal get tired and need to go back to cell body to be degraded and made into new organelles use what type of transport?

Rapid retrograde

What are the two types of synapses?

electrical and chemical

Where can you find electrical synapses?

In CNS, allow ions to pass into dendrite in downstream neuron

What is chemical synapse?

Action potential causes the release of neurotransmitters by exocytosis to synaptic cleft and the neurotransmitter binds to adjacent dendrite which propagates a rapid anterograde in downstream neuron

What is a multipolar neuron?

a neuron that has many dendrites coming off of the cell body; motor, integrator, intermediate

most common in CNS

What is a bipolar neuron?

single dendrite from cell body; sensory receptors (smell, sight, vestibular)

most common in PNS

What is a pseudo-unipolar neuron?

Single dendrite/axon arises from common stem off cell body
-PNS; primary sensory neurons

What are the different neuron types by size?

Golgi type I and Golgi type II

A neuron with long axons that project to distant targets

Golgi type I

What are Golgi II neurons?

-interneurons with small axons
-CNS
-In spinal cord (usually inhibitors & play role in reflexes)

What is the most abundant cell in grey matter (CNS)?

Astrocytes

What are the functions of astrocytes?

structural support, metabolic support, contribute BBB, modulate local blood flow, neurotransmitter uptake & release, promote myelination activity by oligodendrocytes, modulate neuron signaling through regulation of extracellular regulation

What is the ion that astrocytes must absorb during regulation of extracellular ion regulation?

K+

What is vasomodulation?

modulation of local blood flow

Neuroglia derived from mesenchyme and found in CNS

microglia

What is the immunological function of microglia?

Phagocytic role; response to tissue damage, inflammation, and infection

Neuroglia that are epithelial like cells that are typically ciliated and have tight junctions

ependymal cells

Where can you find ependymal cells?

Lining of ventricles and central canal of spinal cord

What do the ependymal cells form in embryology?

Neural tube

What is the structure composed of modified ependymal cells that produce CSF but don't have cilia to direct CSF?

Choroid plexus

Ependymal cells have processes that anchor them to _____________

astroglia

Why must ependymal anchor themselves to astroglia?

No true basement membrane

What are the functions of ependymal cells?

Produce CSF, absorption

What are oligodendrocytes?

A type of neuroglial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system.

Oligodendrocytes are important in maintaining _________.

blood-brain barrier

Myelinate axons of the PNS

Schwann cells

True or False: Small diameter axons are myelinated by Schwann cells and larger diameter are enveloped.

False (other way around)

True or False: Myelinated axons in the CNS can be found in the white matter.

True

Since myelinated axons are found in the white matter, what is found in the grey matter?

cell bodies and glial cells

True or False: White matter is always central in the CNS.

False (peripheral in spinal cord)

What is the components of a nerve from smallest to largest?

Fiber/neurons -> Fascicle --> nerve

What are the connective coverings inside the nerve?

Endoneurium, perineurium, epineurium

Connective tissue that covers the fiber.

Endoneruium

True or False: Perineurium covers the entire outside of a nerve just like periosteum covers bone.

False (covers fasicle)

What does the epineurium cover?

entire nerve

What are all the components of a nerve (the whole big boy)?

Fibers/neuron, fascicle, nerve, endoneurium, perineurium, epineurium, blood vessels, neuroglia, Schwann cells, and fat

What happens to an injured soma (CNS)?

-Chromatolysis (nissl bodies degrade and nucleus pushed to one side)
-total degreneration

True or False: A neuron can come back from chromatolysis.

True

What are the layers of meninges from outer to inner?

-Dura mater
-Arachnoid mater
-Subarachnoid space
-Pia mater

True or False: Dura mater is the vascular layer.

False. Pia mater is vascular layer

What is the dura mater composed of?

dense fibrous connective tissue

What does the dura mater adhere to?

inner table of the skull; arch/body of the vertebra (inside vertebral canal)

What are dural sinuses?

Blood filled spaces acting as veins between the layers of the dura mater

What are dural deflections?

compartmentalize the brain (falx and tentorium)

What is the middle, spider-like web of vascular tissue of meninges?

Arachnoid mater

What is the space that the arachnoid mater is located in?

Subarachnoid space

What is the inner most layer of meninges?

pia mater

Hematomas above dura; shearing of artery

Epidural

Hematomas beneath dura; shearing of vein

Subdural

Middle meningeal artery in pterion is the most likely culprit of what hematoma?

Epidural

Emissary veins that pass through skull and return blood to scalp back to heart are most likely culprit of what hematoma?

Subdural

Why are epidural hematomas so fast?

High hydrostatic pressure of arterial blood

True or False: Subdural hematomas are much faster than epidural.

False

Hematomas that are rare and usually due to a cerebral aneurysm that has ruptured within this layer. Blood mixes with CSF and will raise intracranial pressure.

Subarachnoid

What are the fiber types for somatic afferent fibers?

general senses and some special senses (vision & hearing)

What are the fibers types for somatic efferent fibers?

innervation to most skeletal muscle

What is the cranial nerves distribution?

12 pairs total
-5 motor (efferent) pairs
-3 sensory (afferent) pairs
-4 sensory-motor (mixed) pairs

What is the spinal nerves distribution?

31 pairs total
-8 Cervical (mixed)
-12 Thoracic (mixed)
-5 Lumbar (mixed)
-5 sacral (mixed)
1 coccyx (sensory)

What is the only strictly sensory nerve within spinal nerves?

coccyx

What is the only strictly motor nerve within spinal nerves?

C1 (cervical)

Receptive field depends on:

size and how many are feeding into the downstream neuron

True or False: Smaller, closer together receptive fields are more sensitive.

True

What is the sensory ganglia (contains the cell bodies of neurons) in PNS called?

Posterior (dorsal) root ganglion