Introduction and Organization of Nervous System

NOT INCLUDED: PRIMARY DIVISION OF THE DEVELOPING BRAIN

meninges

brain and spinal cord is covered by system of membranes called —; its bellow the skull

dura, arachnoid, pia

layers of meninges from outmost towards the inner part directly attached to the brain/spine

CSF

brain and spine is suspended in the —;

Shock absorber → protects from impact or sudden movements.

Buoyancy → prevents the brain from pressing down on its own nerves and blood vessels.

Waste removal & nutrient transport → CSF carries away waste products and brings nutrients to brain tissue.

neurons

excitable nerve cells and their processes called axons or nerve fibers

They are nerve cells that send signals (like text messages) really fast.

Each — has long “arms” called axons or nerve fibers that carry these messages to other cells.

Think of — as people making phone calls to each other.

neuroglia

support system of neurons by:

They act like the janitors, bodyguards, and electricians for the neurons, making sure everything works smoothly.

Example: They feed neurons, clean up waste, repair damage, and protect neurons from germs.

gray matter

UNDER INTERIOR OF THE BRAIN; consists of nerve cells that are embedded in neuroglia

white matter

UNDER INTERIOR OF THE BRIAN; Consists of nerve fibers embedded in neuroglia

lipid material in myelin sheaths cover

why is white matter white?

gray matter

• This is where the employees (neurons) sit and do the thinking, planning, and decision-making.

• The brain's — is like the offices in a company where all the work happens.

white matter

• Made up of axon fibers (the "wires" of the neuron) that are covered by myelin sheaths.

• Myelin = a fatty, white-colored insulation that makes signals travel faster.

• It's like internet cables covered in plastic coating for protection and speed.

forebrain, midbrain, hindbrain

division of the brain

cerebrum and diencephalon

parts of the forebrain:

midbrain

parts of the midbrain

medulla, pons, cerebellum

parts of the hindbrain

cervical, thoracic, lumbar, saccral, coccygeal

layers of the spinal cord

7

how many cervical vertebral column

12

how many thoracic vertebral column

5

how many lumbar vertebral column

5 (fused)

how many fused sacrum vertebral column

4 (fused)

how many coccygeal vertebral column

8

how many pair of spinal nerves in cervical vertebral column

12

how many pair of spinal nerves in thoracic vertebral column

5

how many pair of spinal nerves in lumbar vertebral column

5

how many pair of spinal nerves in sacral vertebral column

1

how many pair of spinal nerves in coccyx vertebral column

cranial and spinal nerve with their ganglia

PNS consists of —-

cranial and spinal

— nerve conduct information to and from the CNS

trauma

PNS are not well-protected like the brain or spinal cord (they don’t have a skull or vertebrae), so they are easily injured by —-

nerve fiber/axons and fibrous sheaths

PNS (spinal and cranial nerves) are made up of: —- ; an extension of neurons

foramina

a small hole in the skull where the cranial nerves exit

12

how many pairs of cranial nerves?

31

how many pairs of spinal nerves?

OOOTTAFVGVAH

what are the cranial nerves?

autonomic nervous system

Innervates the body’s involuntary structures

Distributed throughout the PNS and the CNS

nerve plexus

PNS has numerous —- which consist of preganglionic and postganglionic nerve fibers and ganglia

preganglionic; postganglionic

• Imagine you're sending a message from the brain to an organ (like the heart).

• The message can't go in one straight wire; it goes through a relay station (ganglion).

• Before the ganglion = (1) —- fiber.

• After the ganglion = (2) —- fiber.

• The Plexus is like a big messy junction of wires where these meet and crisscross.

Sympathetic and Parasympathetic

ANS is divided into:

Afferent Nerve Fibers

— → Carry information FROM the body TO the brain/spinal cord (sensory signals like organ status).

Efferent Nerve Fibers

— → Carry commands FROM the brain/spinal cord TO the organs (telling the heart to beat faster, stomach to digest, etc.).

subarachnoid space

where CSF surrounds the spinal cord and the brain

foramen magnum; lumbar region

the spinal cord: Begins superiorly at the — in the skull, and terminates inferiorly in the —.

medulla; consus medullaris

the spinal cord: Above the skull, it is continuous with the — of the brain

Below the lumbar region, it tapers off into the —.

Anterior (Ventral) Root

— → Motor → sends signals FROM spinal cord TO muscles (makes you move). AWAY FROM CNS

Posterior (Dorsal) Root

— → Sensory → brings signals FROM body TO spinal cord (lets you feel things).TO CNS

ganglion

each posterior nerve root possesses a posterior root —

gray matter in; white matter out

structure of gray and white matter in the spinal cord

gray matter out; white matter in

structure of gray and white matter in the brain

diencephalon

central part of forebrain and cerebrum

diencephalon

Almost completely hidden from the surface of the brain

thalamus, hypothalamus, and pineal gland

diencephalon is made up of:

thalamus

large, egg-shaped mass of GRAY MATTER

third ventricle

the thalamus lies on either side of the —-

created by choroid plexus - lateral ventricles - 3rd ventricles - 4th ventricles - subarachnoid space - bloodstream

pathway of CSF

thalamus

It is a great relay station on the afferent sensory pathway to the cerebral cortex.

foramen of monro

The anterior end of the thalamus forms posterior boundary of —- (opening between the third and lateral ventricles)

hypothalamus

forms the lower part of the lateral wall and floor of the lateral ventricle

cerebrum

During the process of the development —- becomes enormously enlarge and overhangs the diencephalon, midbrain, and the hindbrain

Why does this happen?

• The — is responsible for complex thinking, moving, feeling, and seeing.

• So as humans develop, it needs to grow bigger to handle all those jobs.

  • The other parts stay smaller but are still very important for basic functions like breathing, heartbeat, and balance.

corpus callosum

crebrum: consist of two cerebral hemispheres which are connected by a mass of white matter, called the —

frontal to occipital bones

cerebrum: each hemisphere extends from the — to the — bones in the skull

cranial fossae

cerebrum: superior to the anterior and middle —

cortex

cerebral hemisphere: — is surface layer of each hemisphere, composed of gray matter

gyri; sulci

Cerebral hemisphere eli5:

brain is like a folded blanket on top of bed bc it wont fit if layed flat

The puffy raised parts = —-.

The dips/lines in between = —-.

The deep, big folds = Fissures.

basal nuclei or ganglia

under cerebral hemisphere: within the hemisphere; central core of white matter with several large masses of gray matter

corona radiata

under cerebral hemisphere: fan shaped nerve fibers

corona radiata

under cerepasses in the white matter to and from the cerebral cortex to the brainstem

internal capsule

where the corona radiata converges goign to the basal nuclei

caudate nucleus

tailed nucleus situated on the medial side of the internal capsule

lentiform nucleus

lens shaped nucleus on the lateral side of the internal capsule

lateral ventricle

cavity present within each cerebral hemisphere

interventricular foramina

lateral ventricle communicates with 3rd ventricle through —

4th ventricle

surrounded by the medulla, pons and cerebellum (hindbrain)

cerebral aqueduct

cavity of the midbrain; communication between 3rd and 4th ventricles

foramen of monro

cavity between lateral and 3rd ventricles

midbrain

narrow part of the brain that connects forebrain and hindbrain

cerebral peduncles

midbrain comprises two lateral halves —

hindbrain

consists of medulla, pons, and cerebellum

medulla oblongata

conical in shape; connects the pons superiorly to the spinal

pons

on the anterior surface of the cerebellum; inferior to the midbrain and superior to the medulla oblongata

cerebellum

lies within the posterior cranial fossa of the skull; posterior to the pons and medulla

vermis

a median portion of the cerebellum, connects the 2 hemispheres

superior cerebellar peduncles

what connects the cerebellum to the midbrain

medial cerebellar peduncles

what connects the cerebellum to the pons

inferior cerebellar peduncles

what connects the cerebellum to the medulla

cerebellar cortex

consists of gray matter; surface of each cerebellar hemisphere

peduncles

composed of large bundles or nerve fibers

4th ventricle

connected inferiorly to the central canal of the spinal cord

4th ventricle

what brings csf to the subarachnoid part of the brain

sensory; smell

type and function of CN I - Olfactory

sensory; vision

type and function of CN II - Optic

motor; controls most eye movement

type and function of CN III - Occulomotor

motor; control the superior oblique muscle for EYE ROTATION

type and function of CN IV - Trochlear

mixed; facial sensation and mastification (chewing)

type and function of CN V - Trigeminal

motor; control the lateral rectus muscle - LATERAL EYE MOVEMENT

type and function of CN VI - Adducens

mixed; facial expression, taste, lacrimal and salivary glands

type and function of CN VII - Facial

sensory; hearing and balance

type and function of CN VIII - Vestibulocochlear

mixed; taste and swallowing

type and function of CN IX - Glossopharyngeal

mixed; controls internal organs

type and function of CN X - Vagus

motor; controls neck and shoulder muscles

type and function of CN XI - Accessory

motor; tongue movement

type and function of CN XII - Hypoglossal

anterior root

— has motor fibers control the contraction of skeletal muscles