Peripheral and Central Nervous System

A comprehensive set of flashcards covering the essential aspects of the Peripheral and Central Nervous System as presented in the lecture.

What are the two main divisions of the nervous system?

The Central Nervous System (CNS) and Peripheral Nervous System (PNS).

What does the somatic nervous system control?

It controls sensory and motor functions related to voluntary movements.

What does the autonomic nervous system regulate?

It regulates involuntary body functions, controlling internal organs and glands.

What are the two main subdivisions of the autonomic nervous system?

The sympathetic and parasympathetic nervous systems.

What structure marks the transition from the brain stem to the spinal cord?

The foramen magnum.

Where does the spinal cord end?

At the first lumbar vertebra (L1).

What is the cone-shaped structure at the end of the spinal cord called?

The conus medullaris.

What is the filum terminale?

An extension of the pia mater that anchors the spinal cord to the coccyx.

What does cauda equina refer to?

The collection of nerve roots that extend from the conus medullaris, resembling a horse's tail.

What is the cervical enlargement?

A region of the spinal cord that is larger due to the number of neurons serving the arms.

What is the lumbar enlargement?

A region of the spinal cord that is larger due to the number of neurons serving the legs.

What are the meninges?

The protective coverings that surround both the brain and the spinal cord.

What type of matter is located deep in the spinal cord?

Gray matter.

What type of matter surrounds the gray matter in the spinal cord?

White matter.

What is the function of the anterior horn in the spinal cord?

It contains the cell bodies of motor neurons.

What is the function of the posterior horn in the spinal cord?

It contains sensory neurons.

What structure connects the right and left halves of the spinal cord?

The gray commissure.

What fluid flows through the central canal of the spinal cord?

Cerebrospinal fluid.

What is the dorsal root responsible for?

Carrying sensory fibers to the spinal cord.

What is the ventral root responsible for?

Carrying motor fibers away from the spinal cord.

What is a mixed spinal nerve?

A spinal nerve that contains both sensory and motor fibers.

What are the three connective tissue layers surrounding nerve fibers?

Epineurium, perineurium, and endoneurium.

How many pairs of spinal nerves are there?

31 pairs.

What is the function of the phrenic nerve?

It innervates the diaphragm for breathing.

What is the cervical plexus?

A network of nerves formed by the ventral rami of spinal nerves C1 to C4.

What is the brachial plexus?

A network of nerves formed by the ventral rami of spinal nerves C5 to T1.

Which nerve innervates the deltoid muscle?

The axillary nerve.

What does the musculocutaneous nerve innervate?

It provides sensory fibers to the lateral forearm and motor fibers to biceps brachii.

What bone is associated with the radial nerve?

The radius.

What is the function of the ulnar nerve?

It provides sensory innervation to the medial aspect of the hand and motor fibers to some flexor muscles.

What is the median nerve responsible for?

It provides sensory fibers to the anterior hand and motor fibers to muscles that move the thumb.

What do the dorsal and ventral rami supply?

Dorsal rami supply the back; ventral rami supply the limbs and front of the body.

What are intercostal nerves?

Nerves that arise from thoracic spinal nerves, providing motor and sensory functions to the intercostal muscles and skin.

What are rami communicantes?

Nerves that connect spinal nerves to the sympathetic trunk ganglia.

What does the lumbar plexus consist of?

Nerves formed by the ventral rami of spinal nerves L1-L4.

What is the largest nerve in the body?

The sciatic nerve.

What are the two components of the sciatic nerve?

The tibial nerve and the common fibular nerve.

Where does the common fibular nerve wrap around?

The head of the fibula.

What do the branches of the sciatic nerve innervate?

Most muscles of the posterior thigh and sensory fibers to the skin of the lower leg and foot.

What muscles do the sciatic nerve affect in the thigh?

Primarily the hamstring muscles.

What is the main pathway for sensory and motor signals in the body?

The spinal cord.

What is proprioception?

The body's ability to sense its position and movement in space.

What is the dorsal root ganglion?

A cluster of sensory nerve cell bodies located near the spinal cord.

What is the role of the sympathetic nervous system?

It prepares the body for 'fight or flight' responses.

What is the role of the parasympathetic nervous system?

It conserves energy and promotes 'rest and digest' activities.

What does the term 'unipolar' refer to regarding sensory neurons?

A type of neuron with one process that splits into two branches.

What type of axons are found in the dorsal root?

Sensory axons.

What are nerve plexuses?

Networks of intersecting nerves that supply body parts.

How many cervical spinal nerves are there?

8 pairs.

What type of fibers does the ventral root carry?

Motor fibers.

What does the posterior funiculus contain?

Ascending sensory pathways.

What do the anterior and lateral funiculi typically carry?

Motor pathways and some ascending pathways.

What is the primary purpose of the spinal cord?

To conduct information between the brain and the rest of the body.

What type of innervation do the rami provide?

Somatic and autonomic innervation.

What is the main function of intervertebral discs?

To cushion the vertebrae and provide structural stability.

What is the function of the anterior horn neurons?

To send motor signals to muscles.

Why is the spinal cord not uniform in diameter?

Due to the concentrations of neurons in certain areas, leading to enlargements.

How does the structure of the spinal cord differ from the cerebrum?

In the spinal cord, gray matter is deep, whereas in the cerebrum, it is superficial.

What does the term 'funiculi' refer to?

Columns of white matter in the spinal cord.

Why is the spinal nerve considered mixed?

It contains both sensory (afferent) and motor (efferent) fibers.

How are the cervical and lumbar plexuses formed?

From the ventral rami of their respective spinal nerves.

What muscles does the phrenic nerve innervate?

The diaphragm.

What type of nerve innervates the skin and muscles of the posterior thigh?

The sciatic nerve.

What does the name 'phrenic' refer to?

Relating to the diaphragm.

What is the primary role of the brachial plexus?

To innervate the skin and muscles of the arm.

What do the branches of the lumbar plexus primarily innervate?

Anterior thigh muscles.

What provides the primary motor control to upper limb muscles?

The brachial plexus.

Which nerve provides sensation to the thumb and index fingers?

The median nerve.

What connects the CNS to the rest of the body?

The peripheral nervous system.

What is the significance of the conus medullaris?

It marks the end of the spinal cord and begins a collection of nerves.

What does the term 'mixed' imply about spinal nerves?

They carry both sensory and motor information.

What is the major nerve of the lumbar plexus?

The femoral nerve.

What do the axillary nerve fibers mainly supply?

The deltoid and teres minor muscles.

What do intercostal nerves innervate?

The muscles and skin between the ribs.

What is the role of the gray rami communicantes?

To connect spinal nerves to the sympathetic trunk.

What happens at the level of the lumbar plexus?

Nerves split and merge to form larger nerves to innervate the lower body.

Which plexus supplies the lower limb?

The sacral plexus.

Which nerves comprise the sciatic nerve?

The tibial nerve and common fibular nerve.

What is the primary sensory nerve for the anterior thigh?

The femoral nerve.

What is the function of intercostal muscles?

To assist with breathing.

What covers the nerve roots as they exit the spinal cord?

Dura mater.

What does the name 'cervical' refer to in the context of the spinal plexus?

Nerves originating from the cervical region of the spinal cord.

What is the largest division of the peripheral nervous system?

The somatic nervous system.

What is one major role of the autonomic nervous system?

To regulate involuntary body functions.

What happens to the mixed spinal nerve shortly after it forms?

It bifurcates into dorsal and ventral rami.

How does the anatomy of the spinal cord differ from that of the brain?

Gray matter is deep in the spinal cord and superficial in the brain.

What type of neuron carries signals toward the spinal cord?

Afferent neurons.

What prevents the spinal cord from moving excessively?

The filum terminale.

What area does the lumbar enlargement serve?

The muscles and skin of the lower limbs.

What is the key protective structure around the spinal cord?

The meninges.

What is a major characteristic of spinal nerves compared to cranial nerves?

All spinal nerves are mixed.

How many pairs of sacral spinal nerves are there?

5 pairs.

What is the primary function of the white matter in the spinal cord?

To transmit signals between different parts of the spinal cord and to the brain.

What sensory functions does the ulnar nerve provide?

Sensation to the medial side of the hand.

What muscles does the radial nerve innervate?

The extensor muscles of the arm and forearm.

What type of neurons are in the dorsal root ganglion?

Unipolar sensory neurons.

How do the muscular movements of the limbs connect with the nervous system?

Through spinal nerves that innervate specific muscles.

What is the primary role of spinal nerves?

To facilitate communication between the spinal cord and the body.

What is the primary role of the anterior funiculus?

Contains descending motor pathways.

What does 'plexus' mean in the context of the nervous system?

A network of intersecting nerves.