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 _____.