Unit 12 Anat

Unit 12 of Anatomy with Dr Truong @ Crafton hills college

The Foramen Magnum between L1, and L2

Spinal cord attatches to the occipital portion of the head through what

Cervical Enlargement is located where? and does what

In the cervical vertebrae, and give rise to upper nerves (Make Bigger)

Lumbar Enlargement is located where? and does what?

Lumbar vertebrae, gives rise to nerves that innervate structure of lower extremities

Conus Medullaris is located where, and has what shape?

Cone like structure located at the inferior end of spine

What anchors the Spinal Cord to the Coccyx

Filum Terminale

A cluster of spinal nerves at the end of the spine extending inferiorly from lumbosacral enlargement is called what?

Cauda equina

The three segmented areas of the spinal cord in order are what?

Cervical, Thoracic and Lumbar

How many PAIRS of spinal nerves are there?

31

What are meninges

Connective tissue surrounding spinal cord, and brain ( have a common infection called meningitis)

The Dura Mater located where and what purpose does it serve?

Tough, outermost protective layer covering the brain and spinal cord

Arachnoid Mater is similar to the Dura mater how? Also what shape does it take

Thin and Whispy layer, utilized to also protect the Brain and spinal cord.

Pia Mater

The filum terminale and this help bind the Spinal cord to the Coccyx, also is bound to the brain.

Subdural

Serous fluid that is thin and slippery , reduces friction between organs and the walls of the body

subarachnoid

CSF and blood vessels within web like strands of arachnoid tissue

Front and back of spinal cord have grooves

Anterior median fissure, and posterior median sulcus located where and do what?

Myelinated Axons are forming tracts

White matter is made of what?

Where is the epidural space located?

l4-l5 T

The central canal is a direction continuation from the third ventricle

False

The central canal is found within grey matter true or false

True

What are meninges

connective tissue membranes surrounding the brain and spinal cord.
Small wording fix: say spinal cord, not “spine,” because spine can mean the bones

Infection of meninges can result in what?

Infection of the meninges can result in meningitis.

Continuous with epineurium

dura mater

Thin and wispy

arachnoid mater

Bound tightly to brain and spinal cord

pia mater

Forms filum terminale

pia mater.

Epidural space contains what?

blood vessels and tissue. Add fat and specify areolar connective tissue

Subdural space contains what?

serous fluid

Subarachnoid space contains what

CSF and blood vessels. More complete: CSF and blood vessels within web-like strands of arachnoid tissue

Does the Spinal nerve only contain afferent neurons or efferent neurons

Contains both Afferent and Efferent Neurons

What is the dorsal root ganglion a collection of?

Cell bodies of pseudo-unipolar sensory neurons.

What type of sensory neurons are found in the dorsal root ganglion?

Pseudo-unipolar sensory neurons.

What color are the sensory neurons shown as on the slide?

Green

Where are motor neuron cell bodies located in the spinal cord gray matter?

In the anterior and lateral horns.

What type of neurons are found in the anterior/ventral gray horn?

Multipolar somatic motor neurons.

What color are the somatic motor neurons shown as on the slide?

Purple

Where are autonomic/sympathetic neurons located?

In the lateral gray horn.

What color are the autonomic/sympathetic neurons shown as on the slide?

Blue.

Axons of motor neurons form what structure?

Ventral roots.

After forming ventral roots, axons of motor neurons pass into what?

Spinal nerves.

What is a reflex?

An automatic response to a stimulus that occurs without conscious thought.

What is a reflex arc?

The neural pathway that controls a reflex.

What are the components of a reflex arc in order?

Sensory receptor → sensory neuron → interneuron → motor neuron → effector organ.

What are reflexes classified by based on number of synapses?

Monosynaptic reflexes and polysynaptic reflexes.

What is a monosynaptic reflex?

A reflex that involves two neurons with no interneuron.

What is a polysynaptic reflex?

A reflex that involves more than two neurons with multiple synapses and interneurons.

What are reflexes classified by based on effector type?

Somatic reflexes and autonomic/visceral reflexes.

What type of effector does a somatic reflex use?

Skeletal muscle.

What type of effector does an autonomic/visceral reflex use?

Smooth muscle, cardiac muscle, or glands.

What are reflexes classified by based on location of integration center?

Cranial reflexes and spinal reflexes.

Where is the integration center for cranial reflexes?

Brain

Where is the integration center for spinal reflexes?

Spinal cord.

What detects a stimulus by generating an action potential?

Sensory receptor.

What conducts action potentials through a nerve and dorsal root to the spinal cord?

Sensory neuron.

In the spinal cord, where is the action potential carried to?

Integration center.

In this example, the integration center involves what type of neuron?

Interneuron, also called an association neuron.

Do simple reflexes involve an interneuron?

No.

The interneuron synapses with what neuron?

Motor neuron.

The motor neuron axon conducts action potentials through what two structures?

Ventral root and spinal nerve.

The motor neuron carries the signal to what?

Effector organ.

What is the final step of the reflex mechanism?

Effector responds.

What are the two examples of reflexes listed on the slide?

Stretch/knee jerk reflex and withdrawal reflex.

What happens during a stretch reflex/knee jerk reflex?

Muscles contract in response to a stretching force.

What makes the stretch reflex/knee jerk reflex unique?

It has no interneuron.

What is a muscle spindle?

Specialized muscle cells that respond to stretch.

What do gamma motor neurons control?

The sensitivity of the muscle spindle.

What part of the muscle spindle do sensory neurons innervate?

The non-contractile centers of the muscle spindle cells.

The sensory neurons from the muscle spindle synapse with what type of motor neurons?

Alpha motor neurons.

What do alpha motor neurons cause the muscle to do?

Contract.

What detects a painful stimulus?

Pain receptors.

What conducts action potentials to the spinal cord?

Sensory neurons.

Sensory neurons synapse with what type of interneurons in the spinal cord?

Excitatory interneurons.

Excitatory interneurons synapse with what type of motor neurons?

Alpha motor neurons.

Excitation of alpha motor neurons results in contraction of what muscles?

Flexor muscles.

What is the final result of the withdrawal reflex?

Withdrawal of the limb from the painful stimulus.

Cool boys lift strong couches

Cervical, brachial, lumbar sacral and coccyx plexus

Cervical plexus

C1–C4; supplies neck structures, skin of the neck, and posterior portion of the head.

Brachial plexus

C5–T1; supplies the upper extremities/arms.

Lumbar plexus

L1–L4; supplies nerves to parts of the lower limb.

Sacral plexus

L4–S4; supplies nerves to parts of the lower limb.

Lumbosacral plexus

Lumbar plexus + sacral plexus; considered together because they are closely related and supply the lower limb.

Coccygeal plexus

S4–Co; supplies pelvic floor muscles and sensory information from skin over the coccyx.

C1–C4

Cervical plexus.

C5–T1

Brachial plexus.

L1–L4

Lumbar plexus.

L4–S4

Sacral plexus.

S4–Co

Coccygeal plexus.

CTL

CERVICAL THORACIC LUMBAR

CERVICAL AREA

invervated arms and upper extremitites

THORACIC

Innvervate the stomach area and back

LUMBAR

Innvervate the legs