Chapter 2.3 The Central Nervous System.pptx

UNIT II: NEUROLOGICAL
FOUNDATIONS OF
BEHAVIOR

Nervous System
Central Nervous
System
Peripheral Nervous
System
brain spinal cord somatic
nervous system
(controls voluntary movements
of skeletal muscles)
autonomic
nervous system
(controls involuntary
muscles like internal
organs and glands)
sympathetic
nervous system
(emergency & stressful situations)
parasympathetic
nervous system
(calming or at rest)

Central Nervous System
• Consists of the brain and spinal cord
• The spinal cord is a narrow column that
starts at the base of the back and extends
up through the neck and into the base of
skull. It is the main pathway to and from
the brain.
• The brain is the location of most
information processing.

Brain
• Technologies that help explore the
brain:
• Electroencephalogram (EEG)- (a record
of brainwave activity made by the
electroencephalograph)
• The EEG detects brain waves that pass
between electrodes that are attached to
the scalp.

• It has been used to reveal electrical
activity associated with relaxation, stages
of sleep, and neurological problems such
as epilepsy.

• Computerized Axial Tomography(CT
Scan) (a brain scanning technique
involving a rotating X-ray scanner and a
high speed computer analysis that
produces slice-by-slice, cross-sectional
images of the brain)
• The CAT scan reveals deformities in
shape and structure that are connected
with blood clots, tumors, and other health
problems.

• Positron-Emission Tomography(PET
Scan)- (a brain imaging technique that
reveals activity in various part of the brain,
based on the amount of oxygen and
glucose consumed or metabolized)
• To trace the metabolism of glucose,
amount of a radioactive compound, called
a tracer, is mixed with glucose and
injected into the bloodstream.

• The PET scan is used by researchers to
see which parts of the brain are most
active when we are, for example, listening
to music, working out a math problem,
using language, or playing chess.

• Magnetic Resonance Imaging (MRI)
• (a diagnostic scanning technique that
produces high resolution images of the
structure of the brain)
• The person lies in a powerful magnetic
field and is exposed to radio waves that
cause parts of the brain to emit signals,
which are measured from multiple angles.

• Functional MRI (fMRI) is a form of MRI
that enables researchers to observe the
brain “while it works” by taking repeated
scans while subjects engage in activities
such as mental processes and voluntary
movements.

• The human brain is divided into three
distinct system (concentric layers), each of
which controls different aspects of human
behavior and thought.
1. central core – innermost section
2. limbic system – surrounds the
brainstem on all sides
3. cerebral cortex – surrounds the
limbic system; responsible for our most
complex mental processes and
behaviors

Chapter 2.3 The Central Nervous System.pptx

THE CENTRAL CORE
• inner most portion of the brain and
consists of the brainstem, the thalamus
and the cerebellum.

• Brainstem
• lowest part of the brain, just above the
spinal cord, consisting of the medulla and
the pons
• The brain stem helps with breathing and
heartbeat.
• All information to and from our body
passes through the brain stem on the way
to or from the brain.

Medulla oblongata – is the lower portion
of the brain stem.
• It controls functions such as breathing or
respiration, blood pressure, and most
importantly, heart rate.
• The medulla also plays roles in sleeping,
sneezing, and coughing.
• Hanging has long been used as a method
of execution because when it breaks the
neck, nervous pathways from the medulla
are severed, stopping respiration

• Pons – it is located above the medulla
oblongata.
- It controls the path of motor and sensory
neurons through the spinal cord and cerebrum
- transmits information about body movement.
.
- Also, the pons contain important centers for
breathing; involved in respiration, attention,
alertness, sleep and dreaming.
- Involved in facial expressions.

• Thalamus
• located on top of the brainstem; acts like a
complex switchboard
• serves as a sensory relay system, channeling
sensory messages to the cortex.
• sensory information from all the senses
except olfaction (smell) is sent to the
thalamus and then routed to the appropriate
area of the cerebral cortex.

• Cerebellum
- Latin word for “little brain”
- is attached to the brainstem and looks like a
small brain in itself.
- It has two hemispheres that are involved in
maintaining balance and controlling motor
(muscle) behavior.

• You may send a command from your
forebrain to get up and walk, but your
cerebellum is key to organizing the
information that enables you to engage in
these movements.
– The cerebellum allows you to place one leg in
front of the other and reach your destination
without tipping over.
– Injury to the cerebellum may impair motor
coordination and cause stumbling and loss of
muscle tone.

The Limbic System
- directly below and surrounded by the cortex
- including the hippocampus, amygdala, and
hypothalamus
Hippocampus and Memory
– Greek for “seahorse” – this structure is so
named because it looks like seahorse.
– The largest structure in the limbic system.
– It plays a crucial role in the processing and
storage of memories.

Amygdala and Aggression
– Greek for “almond” for its almond-shape
– More involved in volatile emotions like
aggression and anger.
– Also connected with a fear response.
Amygdala
– The amygdala is also connected with
vigilance.
– It behaves like a spotlight, focusing
attention on matters that are novel and
important to know more about.

• Hypothalamus-Physical Pleasure
»Important in experiencing physical
pleasure. It also plays a part in
feeding, drinking, and other basic
behaviors.
• Controls and regulate the endocrine
activity and in turn the production of
hormones, this control is particularly important
when the body must mobilize a complex set of
physiological processes (the “fight or flight”
response) to deal with emergencies.
.

• Hypothalamus – maintains homeostasis
• Homeostasis refers to the normal level of
functioning characteristic of the healthy
organism, such as normal body temperature,
heart rate and blood pressure. Ex. If we are too
warm, we perspire and if we are cold, we
shiver.
- Plays an important role in emotions
- It also contains the biological clock that controls
the body’s daily rhythms.

• Hypothalamus-Physical Pleasure
-Controls and regulates
Endocrine System
Body temperature
Sexual Arousal
Hunger
Thirst

• Reticular Formation
• Dense network of neurons, which extends
above the brain stem into the center of the
brain and has connections with areas that are
higher up, screens incoming information and
arouses the higher centers when something
happens that demand our attention. Without
the Reticular Activating System (RAS), we
could be alert or even conscious.
• controls sleep, state of arousal and ability to
focus our attention

• The Cerebral Cortex or Cerebrum
• Cortex – Latin word means “bark”
• The crumpled outer layer of the human brain is
responsible for the uniqueness and complexities of
human behavior;
• responsible for our most complex mental
processes.
• The Cerebrum: largest part of the brain.
• controls your thinking.
• controls your memory.
• controls your speaking.
• controls your movement and identifies the information
gathered by your sense organs.

• The Cerebral Cortex is made up of four
LOBES.
• The cortex has a series of hills and valleys
called convolutions
• Some of the convolutions serve as landmarks
that divide the cortex into 4 separate areas or
lobes.

 Frontal Lobes
• Seat of intelligence
• Involved in purposeful acts like judgment,
creativity, problem solving, and planning –
damage will be lack in planning or
judgment.
• It plays an integral role in the following
functions/actions:
 Memory formation
 Emotions
 Personality
 Decision making or reasoning

• Contains Motor Cortex (PrecentralGyrus):
sends signals/impulses to our voluntary
muscles or muscles that control movements.
• Contains Broca’sArea : Located on Left
Frontal Lobe. responsible for controlling
muscles that produce speech.
• Damage to Broca’s Area is called Broca’s
Aphasia: unable to make movements to talk.
It results in the ability to comprehend speech,
but the decreased motor ability (or inability) to
speak and form words.

Olfactory Bulb
- responsible for sensation/ detection of smell

Parietal Lobes
– top of the back area of the brain
– is responsible for higher sensory information and
language function.
– Spatial awareness and perception
Somatosensory Cortex: receives incoming
touch sensations from rest of the body.

Primary Gustatory Cortex: primary site
involved with the interpretation of the sensation
of taste.
-Association Areas: Any area not associated
with receiving sensory information or
coordinating muscle movements; responsible
for organizing, processing and storing
information

Somatosensory
Cortex/
Postcentral Gyrus
Association
Cortex
Primary
Gustatory Cortex

 Occipital Lobes
• Middle back of the brain
• Primarily responsible for vision.
• Contains Visual Cortex: interprets messages
from our eyes into images we can understand

Visual Association Area
Primary Visual Cortex

Temporal Lobes
- Left and right side of the brain
• Primary Auditory Cortex: Process sound
sensed by our ears; involved in hearing
• Primary Olfactory Cortex: interprets the
sense of smell once it reaches the cortex via
the olfactory bulbs.
- They play an integral role in the following
functions:
• Organization/ comprehension of language
• Information retrieval (memory)

 Wernicke’s Area: Located on the left Temporal Lobe; interprets written and
spoken speech; responsible for language comprehension.
 Wernicke’s Aphasia: a
language disorder that
impacts language
comprehension and the
production of meaningful
language; the person has
difficulty understanding
spoken language but is able
to produce sounds, phrases,
and word sequences. While
these utterances have the
same rhythm as normal
speech, they are not
language because no
information is conveyed.

Two Cerebral Hemispheres
• verbal and rational brain
• logic and sequential tasks
• non-verbal and intuitive brain
• spatial and creative tasks

Corpus Callosum
• The corpus callosum is a large band about 200
million axons connecting the right and left
hemispheres of the cortex. Somehow involved in
transmitting information between the two
hemispheres.
• In split brain patients, the corpus callosum was
being cut to control severe epilepsy (seizure
disorder).
• Result: The person now has “two brains” in one
body.
• This operation is rare and often used as a last
resort.

Brain Plasticity
(Neuroplasticity)
• The idea that the brain, when damaged,
will attempt to find news ways to reroute
messages.
• Children’s brains are more plastic than
adults.

Spinal Cord
• It is a long massive tract of nerves which is
enclosed inside the vertebral column(also
known as the spinal column or back bone;
serves as support of the body and protects
the spinal cord)

Function of the Spinal Cord
• It serves as pathway which nerve impulses
from sensory organs (affectors) pass to the
brain and impulses from the brain (effectors)
return to the muscles and gland.
• Controls many spinal reflexes. It processes
sensory impulses to the effectors without the
assistance of the brain.
– Spinal reflex behaviors are simple, involuntary,
automatic responses to a stimulus
– Involves a simple nerve pathway called a reflex
arc found in the spinal cord (involves sensory
neurons, the spinal cord, and motor neurons)

Spinal
Cord
- carries efferent motor axons
- carries afferent sensory axons
- axon bundles that carry
messages from and to the
brain

Peripheral Nervous System (PNS)
• The sensory and motor nerves that connect the
central nervous system to the rest of the body
• Peripheral means “outer region”
• The system is subdivided into the somatic and autonomic
nervous systems.

Somatic Nervous System
• Contains the motor nerves needed for the
voluntary muscles
– Somatic activity is usually thought of as being
under voluntary control.

Autonomic Nervous System
• The division of the peripheral nervous system
that controls the glands and muscles of the
internal organs like the heart (visceral muscles)
– Autonomic activity is considered involuntary,
for it generally occurs with little awareness or
control
• Controls breathing, blood pressure, and
digestive processes
• Divided into the sympathetic and
parasympathetic nervous systems

Sympathetic Nervous System
• The part of the autonomic nervous system
that arouses the body to deal with
perceived threats
• Dominates in emergency or stressful
situation
• Responds in ways that promote energy
expenditure Ex. increased blood pressure,
heart rate
Fight or flight response

Parasympathetic Nervous
System
• The part of the autonomic nervous system
that calms and brings the body back down to
a relaxed state
• Dominates in relaxed situations, responding
in ways that conserve energy. Ex. Decreased
heart rate and slow the flow of blood to the
skeletal muscles

Endocrine System
Endocrine System: Ductless Glands
 Most of the bodily reactions that results from the activity of the autonomic nervous
system are produced by the action of the system on the endocrine glands.
 Endocrine glands play an important role in growth, sexual and maternal behavior,
the individuals characteristics level of energy and mood, and his reaction to stress.
 Controls many body functions
– exerts control by releasing special chemical substances into the blood called
hormones
– Hormones affect other endocrine glands or body systems

1.PituitaryGland
 majorendocrineglandsituatedbelowthehypothalamus.
 “Mastergland”becauseitproduceslargestnumberofdifferenthormonesandits
primaryfunctionistocontrolandactivatethesecretionofseveralotherendocrine
glands.
 Secretioniscontrolledbythehypothalamusinthebaseofthebrain.

The Pituitary Gland is divided into 2 areas,
1. Posterior Pituitary
 Oxytocin
– influences the contraction of the uterus during childbirth and the reflexive
ejection of milk from the mammary glands.
 Vasopressin
– regulates the amount of water in the body cells which indirectly controls
blood pressure.
– causes the kidney to retain water.
2. Anterior Pituitary
– Growth hormone (somatotropin) – control of timing and amount of
body growth
 Dwarfism– under secretion of the growth hormone early in life
 Giantism – early over-abundance of the growth hormone
 Acromegaly – over secretion of the pituitary growth hormone during adulthood

2.AdrenalGlands
 locatedjustabovethekidneys
 extremelyimportantinneuralfunctioningandintheabilityofthebodytocopewith
stress.
 Twolayers:adrenalmedulla(innercore)andtheadrenalcortex(outerlayer).

Adrenal Medulla
 secretesadrenaline/epinephrine and noradrenaline/norepinephrine.
helps arouse the body to cope with stress and threats.
 Ex. The release of epinephrine causes nervousness, perspiration, constriction of the
blood vessels in the stomach and intestines and make the heart beat faster.
 Epinephrine is of interest to psychologists because it has emotional as well as physical
effects. It intensifies emotions and is central to the experiences of fear and anxiety.
 Norepinephrine stimulates the release of a group of hormones called steroids which
cause the liver to release stored sugar so the body has energy for quick action.

Adrenalcortex
– Regulated by the pituitary hormone ACTH (adrenocorticotrophic hormone)
 corticosteroids(cortical steroids)
– regulate heartbeat, increase resistance to stress, promote muscle development,
and cause the liver to release stored sugar, making more energy available in
emergencies.
 adrenalin androgens(cortin)
– regulates the development of certain adult sexual characteristics.

3.ThyroidGland
– islocatedintheneck
– canbeconsideredasthebody’saccelerator
– Producesthyroxin
– affectsthebodies’metabolism(therateatwhichthebodyusesoxygen
andproducesenergy)

 Thyroxin also help control the rate of physical growth.
– One important element in the thyroxin is iodine
– Underactivity of the thyroid gland results in hypothyroidism, which is
characterized by laziness (sluggishness) and dullness and most of the time being
overweight; accompanied by goiter in the neck.
 Goiter– is a swelling of the thyroid
• lack of iodine in the diet is a contributing factor
– When hypothyroidism (extreme thyroid deficiency) occurs in infancy or early childhood.
The condition is known as cretinism.
 Cretinism – characterized by retarded development, resulting in dwarfism, a big
stomach and scaly skin.
 Hyperthyroidism– result from oversecretion of thyroxin; characterized
by excitability, insomnia, and weight loss.

4. Parathyroid Glands
– within the thyroid are the parathyroid glands. These are two pairs of small
pea-shaped glands which secretes parathormone
 Parathormone –. this hormone regulates the level of calcium and phosphorous and
functions in neuromuscular excitation and blood clotting
– If there is deficiency in parathormone, calcium levels recede and phosphorus
rises .
– A high phosphorus level in your blood can lead to weak bones, itching, bone pain
and hardening of blood vessels.
 Tetany – a condition of physiological imbalance marked by tonic spasm of the muscles
and often associated with deficient parathormones.

5. Pancreas–Isles of Langerhans
– located near the stomach
 Islets of Langerhans– clusters of special cells secreting insulin w/c float in the
pancreas
– Pancreas secretes two hormones which controls the level of blood sugar
or glucose in the blood stream.
 Glucagon
– releases glucose into the bloodstream from the glycogen stored in the liver.
 Insulin
– enables glucose to move out of the blood into the cells of muscles and other
tissues.
– primarily responsible for the control of blood sugar level.
– If insulin is deficient, blood sugar rises above normal amount and causes
diabetes/diabetes mellitus(high blood sugar) also called hyperglycemia.
– If there is an excess of insulin , blood sugar falls below normal and causes
hypoglycemia (low blood sugar)

6. Gonads or Sex Glands
– If it were not for testosterone about six weeks after conception, we would all develop
the external genital organs of females.
– It is not only produced by the testes but also in smaller amounts by the adrenal glands.
– A few weeks after conception, testosterone causes the male sex organs to develop.
– During puberty, testosterone stokes the growth of muscle and bone and the
development of primary and secondary sex characteristics.
 Ovariesproduce estrogen and progesterone as well as small amounts of
testosterone.
– Estrogen is also produced in smaller amounts by the adrenal glands.
 Estrogen is responsible for the female secondary sexual characteristics and
fosters reproductive capacity.
 Progesteronestimulates the female reproductive organs and prepares the
uterus to maintain pregnancy.

ThymusGland
– locatedwithinthechestcavity
– secretesthymosin
– Promotesproductionandmaturationofwhitebloodcells
– thisisknownastheglandofchildhoodasitkeepsachild“childish”
– inhibitsthesexglandsandsexualityinthechildhoodyears.

8. Pineal Body
– This gland is located between the two cerebral hemispheres of the brain.
– It helps the thymus gland and atrophies at puberty.
*atrophy – wasting away of a body part or tissue
 secretes Melatonin
– Helps regulate the sleep-wake cycle and may affect the onset of puberty
– Connected with aging
– Appears to be a mild sedative, and some use it as sleeping pill
– Helps people in adjusting to jetlag

MUSCLES
Functions:
1. Togiveshapetothebody
2. Theyprotecttheinternalorgansofthebody
3. Theyareusedformotionandlocomotion

Three Kinds of Muscle
1. striated muscles– made of long, thin fibers and look striped under the
microscope.
– also called skeletal muscles and sometimes called as voluntary muscles
– found in the face, arms, trunk and legs
2. smooth muscles– control our internal organs. It is also called visceral muscles
– Found in the walls of many of the larger vessels, in the hollow organs, such as the
stomach, intestines and bladder.
– contract more slowly than striated muscles but their response last longer.
– Occasionally called the involuntary muscles
3. cardiac or heart muscles– these are the muscles of the heart
– combine the features of striated muscles and smooth muscles because they are
striated like skeletal muscle but, they contract more slowly and their response
last relatively longer.
– strongest muscles in the body.
– Considered also as involuntary muscles

Characteristics of Muscles:
1. contractility
– is the capacity of muscle to change from a long narrow shape while at rest to a
shorter and thicker form in activity.
– power of muscles to shorten
2. extensibility
– is the characteristic of muscles to become stretched or made longer.
– power of muscle to stretch
3. tonicity
– characteristics of muscles to be in the state of healthy tension or partial
contraction while at rest.
– power to be in partial contraction
4. flexibility
– bending & stretching without breaking
5. elasticity
– it is the power of muscles to resume the original size and shape after contracting
or stretching.

Chapter 2.3 The Central Nervous System.pptx

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