Download Chapter 49 Student Guided Notes

Chapter 49  Nervous Systems
Student Guided Notes
Concept 49.1 Nervous systems consist of circuits of neurons and supporting cells

In most animals with nervous systems, clusters of neurons perform specialized functions.

Such clustering is absent in the cnidarians, the simplest animals with nervous systems.
o In cnidarians, nerve cells form a ___________________________________________.

In more complex animals, the axons of multiple nerve cells may be bundled to form _______________.

Animals with bilaterally symmetrical bodies have more specialized nervous systems.
o Such animals exhibit cephalization, __________________________________________________
________________________________________________________________________________.

In vertebrates, the ___________________ and the _________________________ form the central
nervous system CNS; the _______________________ and _______________________ make up the
peripheral nervous system (PNS).
A variety of glia are present throughout the vertebrate brain and spinal cord.

The major types of glia (connective tissue of nervous system) nourish, support and regulate neurons.
o __________________________________ and ______________________ cells function in axon
myelination, a critical activity in the vertebrate nervous system.
o Astrocytes induce cells that line the capillaries in the CNS to form tight junctions.
o The result is the ________________________________________________, which controls the
extracellular environment of the CNS by restricting the entry of substances from the blood.
The brain and spinal cord of the vertebrate CNS are tightly coordinated.

The brain integrates the complex behavior of vertebrates.

The spinal cord conveys information to and from the brain and generates basic patterns of locomotion.

The spinal cord acts independently as part of the simple nerve circuits that produce reflexes, _________
___________________________________________________ (ex. pulling hand away from hot stove.)

Cerebrospinal fluid is formed in the brain _______________________________________________.
o In mammals, it fills the spaces in the brain and the spinal cord. The function is to act as a shock
absorber.

The brain and the spinal cord contain gray and white matter.
49-1
o Gray matter consists of ____________________________, dendrites, and unmyelinated axons.
o White matter contains ___________________________ with myelin sheaths.
The PNS transmits information to and from the CNS and regulates a vertebrate’s movement and internal
environment.
See Figure 49.8 p. 1083

Sensory (___________________________) Division  incoming neurons

Motor (____________________________) Division  outgoing neurons
o The motor system is also divided:
o Somatic Nervous System  controls signals to skeletal muscles (voluntary and
involuntary.)
o ___________________________ nervous system  is involuntary. (memory tip:
“autonomic is automatic”)
 The three divisions of the autonomic nervous system—____________________,
_____________________________, and ____________________—control the
organs of the digestive, cardiovascular, excretory, and endocrine systems.
See Figure 49.9 p. 1084

The sympathetic and parasympathetic divisions function antagonistically.

The sympathetic division is responsible for ___________________ and ________________________.
(FIGHT OR FLIGHT)
o The heart beats _____________________, the liver converts ___________________ to
_____________________, _______________________ is inhibited, and secretion of
______________________________ from the adrenal medulla is stimulated. Uses norepinephrine as
a neurotransmitter.

The parasympathetic division causes opposite responses that promote __________________ and a
return to _____________________________________________________. (REST AND DIGEST)
o Lowers ___________________________, increases ________________________ production, and
enhances ___________________________. Uses acetylcholine as a neurotransmitter.
49-2
Concept 49.2 The vertebrate brain is regionally specialized
See Figure 49.11 p. 1086-87
o The vertebrate brain has three major regions: the _____________________, __________________,
and ___________________________.
o The forebrain activities include ______________________________________________________,
____________________________________________, ______________________, and _________
______________________________________________.
•
Cerebrum, Diencephalons, Thalmus, Hypothalamus, Epithalmus
o The midbrain coordinates __________________________________________________________
o The hindbrain controls _____________________________________________, such as ________
_______________________________, and coordinates __________________________________,
such as locomotion.
•
Pons, Medulla oblongata, Cerebellum
SUMMARY OF PARTS OF THE BRAIN AND FUNCTIONS
Brainstem (aka “lower brain”)
Major functions of the brainstem: homeostasis, coordination of movement, conduction of
information to higher brain centers
1) Medulla oblongata (also called simply the medulla)  Controls __________________________
______________________________ (ex. respiration, swallowing digestion, heart rate, circulation)
2) Pons  Also helps control automatic functions (ex. regulate breathing centers in the medulla)
3) Midbrain  Acts as a projection center; send coded sensory information to parts of the forebrain
Cerebellum  Functions in coordination, muscle action
Involved in _________________________ and remembering __________________________
Balance and ______________________________ coordination
Thalmus/Hypothalmus/Epithalmus
Epithalmus  Produces _____________________________________ fluid
Thalmus  Main _______________________ center for information going to the ________________
Main ______________________ center for information leaving the cerebrum
Hypothalmus  Important in homeostatic regulation
Control center including _____________________________ functions (sleep/wake),
circadian rhythm
49-3
Source of hormones (refer to CH 45) AND regulates the pituitary
______________________________ of the body
Regulates __________________________________________
Sexual and mating behavior
Initiates _________________________________________ response
Cerebrum  Most highly developed structure in the mammalian brain
Right and left hemispheres are connected by the _________________________________
Right side  math, logical operations, serial sequences of information
Left side  pattern and face recognition, spatial relations, nonverbal thinking
Each hemisphere consists of:
Gray matter (cerebral cortex) - covering
White matter – internal part
Basal nuclei - found deep in the white matter; important in _______________________
___________________________________________________________
Cerebral cortex  (“gray matter”) largest and most complex part
Includes extra layers called the neocortex in mammals
Each side of the cerebrum has four lobes:
Frontal  motor cortex, speech, emotions
Parietal  somatosensory cortex, taste, speech, reading, touch, pain, pressure, temp
Temporal  smell, hearing
Occipital  vision
The brainstem and cerebrum control arousal and sleep.

Arousal and sleep are controlled in part by the __________________________________________, a
system of neurons that passes through the brainstem.
Circadian rhythms rely on a biological clock.

Circadian rhythms are daily cycles of _________________________________________.

Circadian rhythms rely on a biological clock (typically 24 hours), ______________________________
___________________________________________________________________________________.
(This is also partially due to external signals)

Responsible for hormone release and sex drive.
49-4
Emotions depend on many brain structures.

The generation and experience of emotions depend on many brain structures, including the
______________________, ____________________________, and parts of the __________________.
o These structures border the brainstem in mammals and are grouped as the _____________________.
o The limbic system forms a ring around the brainstem and is composed of the hippocampus and the
olfactory cortex.
o The limbic system also functions in motivation, olfaction, behavior, and memory.

Emotions are due to the frontal lobe and the limbic system.

Emotional memory related to fear is stored separately from the memory system that supports explicit
recall of events.
o The brain structure with the most important role in storage of emotional memory is the
___________________________, an almond-shaped mass of nuclei located ___________________
____________________________________________________________________.
Concept 49.3 The cerebral cortex controls voluntary movement and cognitive functions

The cerebrum is essential for awareness of our surroundings, language, _______________________,
____________________________, and consciousness.

Cognitive functions reside in the cortex, __________________________________________________.

Each side of the cerebral cortex has a ______________________, ______________________,
_______________________, and __________________________ lobe, each named _______________
_________________________________________________.
Information is processed in the cerebral cortex.

Some of the sensory input to the cerebral cortex comes from groups of receptors clustered in dedicated
sensory organs, such as the ______________ and ______________________.
o Somatosensory cortex receptors provide information about _____________________, _________,
______________________, __________________________, and the position of muscles and limbs.
o Motor cortex commands particular behavior (ex. moving a limb.)

Most sensory information coming into the cortex is directed via the _______________________ to
___________________________________________________________________________________.
o The thalamus directs different types of input to distinct locations: Visual information is sent to the
occipital lobe, whereas auditory input is directed to the temporal lobe.
49-5

Frontal lobes influence what are often called “executive functions.” (ex. planning, decision making)
Language and speech are localized in the cerebrum.

Damage to particular regions of the cortex by ____________________, ______________________, or
______________________ produce distinctive changes in behavior.

Discoveries by Pierre Broca and Karl Wernicke determined the following regarding language and
speech:
o A small region of the ____________________________________________, Broca’s area,
controls muscles in the face.
o A posterior portion of the left ________________________ lobe, Wernicke’s area controls
the ability to _______________________________________ but not _________________
__________________________________.
Cortical function is lateralized.

The left hemisphere is more adept at __________________ and _______________________________,
while the right hemisphere is dominant in the recognition of __________________________________,
spatial relations, and ________________________________________.

The two hemispheres trade information through the fibers of the _______________________________.
Concept 49.4 Changes in synaptic connections underlie memory and learning
The nervous system is plastic.

The nervous system has a great capacity to be remodeled ____________________________________
______________________________________,
o This is called neural plasticity.

Autism, a developmental disorder that first appears early in childhood, involves __________________
__________________________________________________________________________________.
o Children affected with autism display ____________________________________________ and
______________________________________________, as well ___________________________
____________________________________________________.
Memory and learning rely on neural plasticity.

The formation of memories is due to neural plasticity.

We constantly check what is happening against what just happened a few moments ago, holding
information in short-term memory and releasing it if _______________________________________.
49-6
o To retain knowledge of a name or phone number requires activation of mechanisms of __________
__________________________________________.
o If we need to recall the name or number, ________________________________________________
________________________________________________________________________________.

When memories are made long-term, the links in the _____________________________ are replaced
by more permanent connections within the ____________________________________________.
o Some of this consolidation of memory is thought to occur during ______________________.
o Repetition is also a factor – “practice makes perfect”, more accurately stated as “practice makes
permanent” (so practice it correctly!!)

The hippocampus is essential for ________________________________________________________
but not ______________________________________________________.
o Individuals who suffer damage to the hippocampus cannot ________________________________
_________________________ but can _______________________________________________
__________________________________________.

Transfer of information from short-term to long-term memory is enhanced by ____________________
___________________________________________________________________________________
___________________________________________________________________________________.

Motor skills (“skill memory” such as riding a bike, playing the piano) are usually _________________
_________________________________. Once learned bad habits are hard to break (ex. playing a piece
with the wrong fingering technique)
*** Both the nervous system and the endocrine system use chemical signaling and chemical messengers
(from axons) and the response depends on the receptors mode of action ***
THE FOLLOWING IS JUST FOR REFERENCE IN YOUR NOTES BUT WILL NOT BE ON THE
TEST AND IS NOT INCLUDED IN THE POWERPOINT:
Concept 49.5 Many nervous system disorders can be explained in molecular terms

Major research efforts are under way to identify genes that cause or contribute to disorders of the
nervous system.
 Family studies may help scientists distinguish between genetic and environmental variables.
Schizophrenia is a severe mental disturbance characterized by psychotic episodes.
 About 1% of the world’s population suffers from schizophrenia, a severe mental disturbance
characterized by psychotic episodes in which patients have a distorted perception of reality.
 People with schizophrenia typically experience hallucinations and delusions.
Depression is a disorder characterized by depressed mood plus abnormalities in sleep, appetite, and energy
level.
49-7

Individuals affected by major depressive disorder have periods in which once enjoyable activities
provide no pleasure and provoke no interest.
o Major depression affects about one in every seven adults at some point, and twice as many women
as men.
 Bipolar disorder involves swings of mood from high to low and affects about 1% of the world’s
population.
Drug addiction is linked to the brain’s reward system.
 Drug addiction is a disorder characterized by compulsive consumption of a drug and loss of control in
limiting intake.
 Addictive drugs include stimulants, such as cocaine and amphetamine, and sedatives, such as heroin.
 All of these drugs, as well as alcohol and nicotine, are addictive for the same reason: Each increases
activity of the brain’s reward system, neural circuitry that normally functions in pleasure, motivation,
and learning.
Alzheimer’s disease is dementia characterized by confusion and memory loss.

The incidence of Alzheimer’s disease is age related, rising from about 10% at age 65 to about 35% at
age 85.
 The disease is progressive, with patients gradually becoming less able to function and eventually
needing to be dressed, bathed, and fed by others.
o Patients also lose their ability to recognize people, including their immediate family, and may treat
them with suspicion and hostility.
 Postmortem examination of the remaining brain tissue reveals two characteristic features—amyloid
plaques and neurofibrillary tangles.
Parkinson’s disease is a motor disorder including muscle tremors, poor balance, a flexed posture, and a
shuffling gait.
 Like Alzheimer’s disease, Parkinson’s disease is a progressive brain illness and is more common with
advancing age.
o The incidence of Parkinson’s disease is about 1% at age 65 and about 5% at age 85.
49-8