THE NERVOUS

SYSTEM

Overview

Two major divisions: _____nervous system and _____ nervous system

CNS – _____ and spinal cord; located in _____ cavity

Spinal cord – conducts sensory info from the _____NS to the _____; conducts motor info from the brain to effectors (muscles and glands); _____ center

Neurons (4:43)

Overview Brain – receives input from the _____ _____ as

well as from its own nerves; central processing center

White matter – bundles of axons covered with _____ (myelin gives it ________ appearance); found in brain and cord

Gray matter – masses of dendrites and cell bodies; not covered with _____ so it appears _______

Three meninges – _____, _____, and _____ maters; CSF in between arachnoid and pia

Blood-Brain Barrier Tight _____ junctions between endothelial

cells of brain capillaries Maintains brain _____. The brain must be

kept isolated from any changes in the _____, particularly after meals or exercise.

Allows essential molecules (like _____ and glucose) to pass from the _____ to the CNS but blocks more massive molecules like hormones and neurotransmitters

Blood-Brain Barrier Also prevents most _____ from infiltrating the

CNS _____ cells such as lymphocytes, monocytes

and neutrophils cannot penetrate this barrier. Why is this a concern?

Prevents full-blown _____ response in the CNS (bad for delicate neural tissue)

Creates challenges for scientists as they develop CNS _____ and chemotherapies. Why?

Many of these meds require intrathecal administration, rather than vascular injection or taking a pill

BBB

Challenges of the BBB (4:53)

BBB animation (1:58)

BBB crossed for the first time! (3:25)

Computer-generated Image of the BBB

Cerebrospinal Fluid Produced in masses of special _____ called choroid

plexuses; 99% H2O Five primary functions:

Buoyancy for the brain, c_____, chemical stability, f_____ system, clears out _____ (esp. when we sleep)

Located between the _____ and _____ maters Flows uninterrupted through the CNS through the

cerebrospinal canal of the spinal cord to the _____ in the _____ then exits CNS through veins draining the brain

Constant _____ must be maintained The total volume of CSF in an adult is about _____ ml.

CSF is produced at a rate of 600-700 ml per day

The Brainstem Three parts: medulla oblongata, pons, and

midbrainMedulla controls _____ functions like breathing,

heartbeat, and blood _____; reflex centerPons is the relay station between the _____

and the rest of the CNS; may play a role in _____; works with medulla to regulate _____ rate

Why do we dream? (6:30)Midbrain acts as a relay station between _____

and spinal cord or cerebellum; also controls sensory processes

The Brain

Cerebellum – “little brain”; c_____, equilibrium and b_____; muscle tone; only 10% of brain but contains more _____ than the rest of the brain combined; _____ working part of the brain; capable of making _____ based on previous experiences; enables rest of brain to work more _____ because it can carry out tasks _____ without conscious thought (speech)

The Brain Cerebrum – “brain”; only

part of the brain involved in consciousness; largest part; divided into two _____; superficial layer called the _____, which is highly folded (increases _____ _____); neocortex (higher intelligence – found only in _____); contains four distinct areas called _____

The Brain

Hypothalamus – maintains ____; center for _____, thirst, emotions, body _____, _____ rhythms; connected to autonomic NS; controls the _____ gland (endocrine system) 

Thalamus – sensory and _____ functions; last relay site before info reaches the _____; organizes info and sends it to appropriate areas of the _____

Human Biological Clock (Circadian Rhythms)

Sleep Patterns (Monitored by Josie Harrington’s phone while she slept)

The Brain

Cerebrum

Cerebellum

Medulla Oblongata

Spinal Cord

ThalamusHypothalamus

Pituitary

Corpus Callosum

The Brain

Limbic system – includes portions of the thalamus, hypothalamus, and cerebrumAmygdala – memory, emotions, fearHippocampus – memory and learning;

converts _____-_____ memories into _____-_____; associates sensory experiences (like smells) to _____; spatial relationships

Limbic System

Man with no memory (3:05)

World memory champion - Part 1 (4:58)

World memory champion - Part 2 (5:34)

The Spinal Cord Extension of the _____ Ends between L1 and L2

Spinal taps ALWAYS done below _____

Conducts impulses between periphery and _____

Central canal (extension of brain ventricles) that contains _____

Covered by the three _____

Ascending and descending nerve tracts

Reflexes and the Reflex Arc

Reflexes are r____, p____, and in____ responses to stimuli.

Involve as few synapses as possible – Why?

What organ is missing from a typical reflex arc?

Why do we feel pain after we’ve reacted?

Peripheral Nervous System (PNS) Somatic NS – controls _____

movement; acetylcholine is primary _____; includes all the neurons connected with _____ muscles, skin, and sense organs

Autonomic NS – controls _____ movement; unconscious processes; maintains _____; 2 divisions: _____ and _____

Autonomic NS Sympathetic division –

“_____-or-_____” response; energy generation; inhibits digestion; diverts blood from _____ system and skin to _____ tissue and _____; dilates breathing passages; increases _____ _____; dilates _____ (increased light); norepinephrine, aka, adrenaline

Fight-or-Flight (6:35)

Autonomic NS Parasympathetic

division – “_____ and _____”; increases blood flow to _____ system; promotes digestion and absorption; constricts _____ _____; slows _____ _____; acetylcholine

Intro to Neuroglia (Glia) Neuroglia literally means “_____ _____”. They’re the supporting cast for the neurons Their four main functions are:

To surround neurons and _____ them in placeTo supply _____ and O2 to neuronsTo _____ one neuron from anotherTo destroy _____ and remove _____ neurons

Each type has its own specialized _____ & _____

Because glial cells _____ and neurons generally don’t, most brain _____ are gliomas.

There are two in the PNS and four in the CNS.

PNS Neuroglia (Glia) Schwann cells – named after Theodor _____; form

the insulative _____ _____ around axons (like the covering around electrical wires); enable quick _____ of electrical _____ within an _____; outer layer called the _____ (protective & regenerative layer of Schwann)

PNS Neuroglia (Glia) Satellite cells – _____, cushioning cells; appear to be

involved in the regulation of _____; connect neurons with blood _____, which means?

It appears that they’re _____ cells that carry out a wide variety of _____; still much to be _____ about them

CNS Neuroglia (Glia) Microglial cells – _____-_____crew;

phagocytic; activated after _____ or disease and remove damaged cells or kill invading _____; derived from blood _____ _____

Microglial cell (green) and astrocyte (red) after injury to a capillary. The microglial cell extensions surround the injured area – Why? What’s it doing?

CNS Neuroglia (Glia) Astrocytes – they’re the CNS equivalent to

satellite cells in the PNS, which means . . . Integral part of the _____-_____ barrier Most abundant cell in the brain

CNS Neuroglia (Glia)

Ependymocytes – line cavities (_____) within the CNS; assist in production and circulation of _____ with the help of hair-like cellular extensions called _____

CNS Neuroglia (Glia) Oligodendrocytes – like Schwann cells,

form the _____ _____ around axonsAs many as 50 axons! (Schwann cells: only one)

Oligodendrocyte supplying myelin for numerous axons

Glial cell review (8:00)

Nodes of Ranvier Nodes of Ranvier – gaps between Schwann cells (PNS)

and oligodendrocytes (CNS) that increase the conduction of an _____ down an _____; allow impulse to “_____” down the axon (saltatory conduction)

Because the axonal membrane is exposed at the node, nutrients and wastes are able to enter and exit the _____.

The SynapseVesicles (purple spheres) are filled with _____. At the synapse, the vesicles fuse with the neuron’s cell _____ and release their _____, which are then picked up by _____ receptors on the receiving neuron’s cell _____.