Download Chapter 12: Neural Tissue

Our Very Own Human Computer
CHAPTER 9 – THE NERVOUS SYSTEM
OUR STANDARD THAT WE WILL COVER…

Standard 4.1 – Investigate the anatomy and
physiology of the central and peripheral
nervous systems from the microscopic to the
systemic levels
OUR OBJECTIVE FOR TODAY

By the end of this class, you will be able to
describe the neural tissue, the meninges, and
the cerebrum
NEURAL TISSUE

Contains 2 kinds of cells:
 neurons:
 cells
that send and receive signals
 neuroglia
 cells
(glial cells):
that support and protect neurons
 https://www.youtube.com/watch?v=vyNkAuX29OU
ORGANS OF THE NERVOUS SYSTEM
Brain and spinal cord
 Sensory receptors of sense organs (eyes, ears,
etc.)
 Nerves connect nervous system with other
systems

ANATOMICAL DIVISIONS OF THE NERVOUS
SYSTEM
1.
2.
Central nervous system (CNS)
Peripheral nervous system (PNS)
THE CENTRAL NERVOUS SYSTEM
THE CENTRAL NERVOUS SYSTEM (CNS)
Consists of the spinal cord and brain
 Contain neural tissue, connective tissues, and
blood vessels

FUNCTIONS OF THE CNS

Are to process and coordinate:
 sensory
data:
 motor commands:
 higher functions of brain:
 intelligence,
memory, learning, emotion
THE BRAIN
THE HUMAN BRAIN
Ranges from 750 cc (cubic cm) to 2100 cc
 Contains almost 98% of the body’s neural
tissue
 Average weight about 1.4 kg (3 lb)
 Some other interesting facts…

 https://www.youtube.com/watch?v=7Jd0ahtfd74
 https://www.youtube.com/watch?v=D33Aj5w061g
MENINGES

There are 3 layers (meninges) that surround
the brain and spinal cord
 Pia
mater – covers the brain
 Arachnoid – middle layer
 Dura mater – outermost layer that is attached to
the interior of the skull
MENINGES
6 REGIONS OF THE BRAIN
Cerebrum
 Cerebellum
 Diencephalon
 Mesencephalon
 Pons
 Medulla oblongata

REGIONS OF BRAIN

Cerebrum
Largest part of brain
 Controls
higher mental functions
 Memory storage
 Skeletal Muscle Control
 Divided into left and right cerebral hemispheres
 Surface layer of gray matter (neural cortex)
REGIONS OF BRAIN

Cerebrum Neural Cortex
 Also
called cerebral cortex
 Folded surface increases surface area
 Elevated ridges (gyri)
 Shallow depressions (sulci)
 Deep grooves (fissures)
 “Squiggly
Lines”
REGIONS OF BRAIN
TODAY’S OBJECTIVE

By the end of today’s class, you will be able to
describe and label all portions of the human
brain by labeling a diagram and filling in the
“Structure and Functions” worksheets
REGIONS OF BRAIN

Cerebellum
 Second
largest part of brain
 Coordinates repetitive body movements
 2 hemispheres
 Covered with cerebellar cortex
REGIONS OF BRAIN

Diencephalon
 Located
under cerebrum and cerebellum
 Links cerebrum with brain stem
 Contains thalamus and hypothalamus
REGIONS OF BRAIN

Diencephalon (Con’t)
 Thalamus:
 relays
and processes sensory information
 Hypothalamus:
 hormone
production
 emotion
 thirst/hunger
 body
temp.
 controls circadian rhythms (day–night cycles)
REGIONS OF BRAIN

The Brain Stem
 Processes
 spinal
infomation between:
cord and cerebrum or cerebellum
 Includes:
 mesencephalon
 pons
 medulla
oblongata
REGIONS OF BRAIN

The Brain Stem (Con’t)
 Mesencephalon
 Also
called midbrain
 Processes sight, sound, and associated reflexes
 Maintains consciousness
 Pons
 Connects
cerebellum to brain stem
 Is involved in somatic and visceral motor control
REGIONS OF BRAIN

The Brain Stem (Con’t)
 Medulla
Oblongata
 Connects
brain to spinal cord
 Relays information
 Regulates autonomic functions:
 Cardiovascular, respiratory, and digestive systems
LIMBIC SYSTEM


Includes tracts between the cerebrum and
diencephalon.
Functions are:




Establishing emotional states
Linking the conscious, intellectual functions of the cerebral
cortex with the unconscious functions of the brain stem.
Facilitating memory storage and retrieval.
The cortices of the brain enable you to do tasks, the
limbic system makes you want to do them.
WRAPPING IT ALL UP

Can you live without part of your brain?
 https://www.youtube.com/watch?v=uWkJnS8RHyE
BELL WORK
Pull out your fully-labeled diagram of the brain
 Just like previous chapters – color code each
part of the brain that we labeled
 Use this time to review as you color coordinate
 You have 12 minutes for this activity

TODAY’S OBJECTIVE

By the end of the day, students will be
proficient in “special areas” of the brains and
their functions by group discussion.
SENSORY AND MOTOR AREAS OF THE
CEREBRUM
THE CEREBRAL CORTEX
Figure 14–12b
OTHER INTEGRATIVE AREAS

Speech center (Broca’s Area):



Prefrontal cortex of frontal lobe:



is associated with general interpretive area
coordinates all vocalization functions
integrates info from sensory association areas
performs abstract intellectual activities (e.g., predicting
consequences of actions)
Hippocampus


sorts and integrates emotions and memories
deep portion on the temporal lobe
THE LEFT HEMISPHERE

In most people, left brain (dominant
hemisphere) controls:
 reading,
writing, and math
 decision-making
 speech and language
THE RIGHT HEMISPHERE

Right cerebral hemisphere relates to:
 senses
(touch, smell, sight, taste, feel)
 recognition (faces, voice inflections)
MEN’S VS. WOMEN’S BRAIN – THE GREAT MIND
GAME

For all your hard work so far, enjoy your treat…
 https://www.youtube.com/watch?v=xDf0WJPqLE4
 https://www.youtube.com/watch?v=0BxckAMaTDc
THE SPINAL CORD
SPINAL CORD

Adult Spinal Cord
 About
18 inches (45 cm) long
 1/2 inch (14 mm) wide
 Ends between vertebrae L1 and L2

Carries signals between brain and PNS

Responsible for reflexes
WRAPPING IT ALL UP

Spinal Cord Dissection
 https://www.youtube.com/watch?v=dLMoP5bTvI8
BELL WORK
Take a few of minutes to jot down a couple of
examples of people that you have known in
your life that have experienced or struggled
with a nervous system disorder. What were the
symptoms and struggles?
 After you finish, get out your notes.

TODAY’S OBJECTIVE

By the conclusion of class, you will be able to
differentiate between common diseases and
disorders of the CNS, along with introductory
material of the PNS.
COMMON DISORDERS AND DISEASES OF THE CNS
MULTIPLE SCLEROSIS (MS)





200,000-400,000 people in the US affected
The body ceases to function in certain areas due to demyleniation
No known cure
 Some are chronic
 Some are flare-ups
Vision, speech, and balance can be severely affected
https://www.youtube.com/watch?v=M7O78LvrNSQ
TRAUMATIC BRAIN INJURY (TBI)





Can range from mild
concussions to severe
brain damage
Can cause a hematoma
Symptoms can include
dizziness, vomiting, blurred
vision, head-ache, etc.
Severe cases can lead to a
vegetative state
https://www.youtube.com/
watch?v=eXqkBmjPeBs
CEREBRAL PALSY (CB)





Child is usually born with
this
Can affect gross motor
skills and speech
Most live normally with
some assistance
Some severe cases lead to
paralysis or severe mental
deficiencies
Even in pop culture:
https://www.youtube.com/
watch?v=g9gBVn_KzBA
Everything Not in the Brain or Spinal Cord
THE PERIPHERAL NERVOUS SYSTEM
THE PERIPHERAL NERVOUS SYSTEM (PNS)

Includes all neural tissue outside the CNS
PRIMARY FUNCTIONS OF THE PNS
1.
2.
Deliver sensory information to the CNS
Carry motor commands to peripheral tissues
and systems
WRAPPING IT ALL UP

Group discussion about someone that you
know that has been affected by one of the
brain conditions that you wrote down today, or
one that we just discussed - only share if you
feel comfortable doing so.
I
will go first to get everyone started.
TODAY’S OBJECTIVE

By the end of class today you will be able to
differentiate between the portions of the PNS
and perform a cranial nerve test.
NERVES

Also called peripheral nerves:
 bundles
of axons with connective tissues and blood
vessels
 carry sensory information and motor commands in
PNS:
 cranial
nerves—connect to brain
 12 pair
 spinal nerves—attach to spinal cord
RECEPTORS AND EFFECTORS

Receptors:
 detect
changes or respond to stimuli
 neurons and specialized cells
 complex sensory organs (e.g., eyes, ears)

Effectors:
 respond
to efferent signals
 cells and organs
FUNCTIONAL DIVISIONS OF THE PNS

Afferent division:
 carries
sensory information from PNS sensory
receptors to CNS

Efferent division:
 carries
motor commands from CNS to PNS muscles
and glands
THE EFFERENT DIVISIONS OF THE PNS
Somatic nervous system (SNS)
 Autonomic nervous system (ANS)

THE SOMATIC NERVOUS SYSTEM (SNS)


Includes all somatic motor neurons that
innervate skeletal muscles
Controls skeletal muscle contractions:
 voluntary
muscle contractions
 involuntary muscle contractions (reflexes)
THE AUTONOMIC NERVOUS SYSTEM (ANS)

Controls subconscious actions:
 contractions
of smooth muscle and cardiac muscle
 glandular secretions
DIVISIONS OF THE ANS

Sympathetic division:
 has
a stimulating effect
 Fight
or flight
 https://www.youtube.com/watch?v=FBnBTkcr6No

Parasympathetic division:
 has
a relaxing effect
STANDARD

Standard 4.1 – Investigate the anatomy and
physiology of the central and peripheral
nervous systems from the microscopic to the
systemic levels
TODAY’S OBJECTIVE

By the end of class today, you will be able to
describe the neuron and its components.
NEURONS

The basic functional units of the nervous
system
 More
than 100 BILLION!
 https://www.youtube.com/watch?v=vyNkAuX29OU
FUNCTIONAL CLASSIFICATIONS OF NEURONS

Sensory neurons:
 afferent

neurons of PNS
Motor neurons:
 efferent
neurons of PNS
FUNCTIONS OF SENSORY NEURONS
Monitor internal environment
 Monitor effects of external environment

MOTOR NEURONS
Carry instructions from CNS to peripheral
effectors
 Via efferent fibers (axons)

THE STRUCTURE OF NEURONS
Figure 12–1
DENDRITES

Highly branched
 many
fine processes
 receive information from other neurons
 80–90% of neuron surface area
THE AXON
Long shaped
 Carries electrical signal to target
 Axon structure is critical to function

THE SYNAPSE
Area where a neuron communicates with
another cell
 Synaptic Cleft

 The

small gap
Synaptic Knob
 Is
expanded area of axon
THE SYNAPSE
Figure 12–2
MYELINATION

Increases speed of action potentials

Insulation

Makes nerves appear white
NEURON
SCHWANN CELLS
Form myelin sheath around peripheral axons
 1 Schwann cell sheaths 1 segment of axon:

 many
Schwann cells sheath entire axon
SCHWANN CELLS
Figure 12–5a
ELECTRICAL IMPULSES IN NERVES
ION MOVEMENTS AND ELECTRICAL SIGNALS
All cell membranes produce electrical signals
by ion movements
 Transmembrane potential is particularly
important to neurons

MEMBRANE PROCESSES IN NEURAL ACTIVITIES
Figure 12–7 (Navigator)
ACTION POTENTIALS
ALL-OR-NONE PRINCIPLE

If a stimulus exceeds threshold amount:
 the
action potential is the same no matter how
large the stimulus

Action potential is either triggered, or not