Bell Work
•
Using your book and your artistic
ability, draw a detailed complete
picture of a neuron.
•
Be sure to label as many parts as you
can.
•
This picture will be your copy of a
neuron that will aid in your studying
Today
•
Objective:
Describe parts of a neuron andexplain how its impulses are generated.
•
Review Unit 1 & 2 Test
•
Introduce biological psychology
•
The Neuron
•
Neural Communication
•
Introduce Brain Project.
Neuroscience
Parts of a neuron
Action potential
Major
neurotransmitters
Neural and Hormonal
Systems
Neurons are to the nervous system as
hormones are to the endocrine system
Nervous System- fast response and quick to
leave
History of the Mind
In 1800, Franz Gall suggested, that bumps of the skull represented mental
abilities. His theory though incorrect,
nevertheless
proposed different mental abilities were
modular. Phrenology B ett m an
/ C
or
Neural Communication
The body’s information system is built from billions of interconnected cells called
The Neuron
• Types of Neurons:
– Sensory Neurons:
• Carry incoming information from sensory receptors to
the brain/spinal cord
• E.g. Perceiving something as “hot”
– Motor Neurons:
• Carry outgoing information from the brain/spinal cord to
the muscles/glands • E.g. Clenching a fist
– Interneurons:
• Located within the brain/spinal cord
• Communicate internally between sensory inputs and motor outputs
Neural Communication
Note similarity of brain regions involved with information processing of similar kind.
Neurobiologists and other investigators understand that information processing in
Neuron
Parts of a Neuron
Cell Body: Life support center of the neuron.
Dendrites: Branching extensions at the cell body.
Receives messages from other neurons.
Axon: Long single extension of a neuron, covered
with myelin sheath to insulate and speed up messages through neurons.
Terminals of axon (terminal buttons): Branched
Action Potential
A neural impulse. A brief electrical charge that travels down an axon generated by the
Depolarization &
Hyperpolarization
Depolarization: Depolarization occurs, when positive ions enter the neuron, making it more susceptible to fire an action potential. When negative ions
enter the neuron making it less
susceptible to fire, hyperpolarization
Threshold
Threshold: Each neuron receives
depolarizing and hyperpolarizing currents from many neurons. When the
depolarizing current (positive ions) minus the hyperpolarizing current (negative
ions) exceed minimum intensity
Refractory Period & Pumps
Refractory Period: After a neuron has fired an action potential it pauses for a short
period to recharge itself to fire again.
Sodium-Potassium Pumps:
Action Potential Properties
All-or-None Response: When depolarizing current exceeds the threshold a neuron
will fire, and below threshold it will not.
Intensity of an action potential remains the same, throughout the length of the
Bell Work
•
Review material from yesterday.
– What questions do you have.
•
Today:
– Synapse
– Neurotransmitters
– Agonist and Antagonist – Nervous Systems
– Endocrine system
Synapse
Synapse [SIN-aps] a junction between the axon tip of the sending neuron and the
dendrite or cell body of the receiving
Neurotransmitters
Neurotransmitters
(chemicals) released from the sending
neuron, travel across the synapse and bind to
receptor sites on the receiving neuron,
thereby influencing it to generate an action
potential.
Reuptake
Neurotransmitters in the synapse are reabsorbed into the sending neurons
through the process of
reuptake. Don’t move on to the next neuron.
For example:
People who suffer from depression have lower levels of serotonin. They
may take an SSRI which blocks reuptake (thus flooding the synapse with
How Neurotransmitters Influence
Us
Serotonin pathways are involved with
mood regulation (depression).
Dopamine Pathways
Dopamine pathways are
involved with diseases like
schizophrenia and Parkinson’s disease.
Lock & Key Mechanism
Neurotransmitters bind to the receptors of the receiving neuron in a key-lock
Bell Work
•
Review with a partner.
•
What Questions do you have about
the nervous system?
•
Today:
– Nervous system – Endocrine System
– Major brain structures
Nervous System
Nervous system
Afferent/Efferent neurons
Parts of the autonomic nervous system
Nervous System
Central Nervous
System (CNS)
Peripheral Nervous
The Nervous System
Nervous System: Consists of all the nerve cells. It is the body’s speedy,
electrochemical communication system.
Central Nervous System (CNS): the brain and spinal cord.
Peripheral Nervous System (PNS): the
Kinds of Neurons
Sensory Neurons (afferent) carry incoming information from the sense receptors to the CNS. Motor Neurons (efferent) carry outgoing
information from the CNS to muscles and glands. Interneurons connect the two neurons.
Sensory Neuron (Bipolar) Interneuron Neuron
(Unipolar)
Kinds of Glial Cells
Glial cells function as support cells ,
hold together message sending neurons and support
their functioning. Kind of like “glue”
Example: Schwann cells insulate
Peripheral Nervous System
Somatic Nervous System: The division of the peripheral nervous system that controls the body’s skeletal muscles. You have “some” control of this.
The Nerves
Nerves consist of neural
“cables” containing many axons. They are
part of the peripheral nervous system, and
connect muscles, glands, and sense organs to the central
Autonomic Nervous System (ANS)
Sympathetic Nervous System: division of the ANS that arouses the body, mobilizing its energy in stressful situations. Gets you ready for fight or flight.
Parasympathetic Nervous System:
division of the ANS that calms the body, conserving its
Autonomic Nervous System (ANS)
Sympathetic NS “Arouses”
(fight-or-flight)
Parasympathetic NS
“Calms”
The Endocrine System
Endocrine System
is the body’s “slow” chemical
communication system.
Communication is carried out by
hormones
Hormones
Hormones are chemicals synthesized by the endocrine glands and secreted in the
bloodstream. Hormones affect the brain and many other tissues of the body.
Hormones remain in your system longer than neurotransmitters.
For example, epinephrine (adrenaline) increases heart rate, blood pressure, blood
Pituitary Gland
Is called the “master gland.” Anterior pituitary lobe releases hormones that regulate other glands. Posterior lobe
Pineal gland
•
Located near the center of the brain
between the two hemispheres,
shaped like a pine cone
•
Secretes the hormone melatonin
which influences our sleep/wake
cycle
•
Connects the endocrine
Thyroid & Parathyroid Glands
Adrenal Glands and Pancreas
Adrenal glands consists of adrenal medulla and cortex. Medulla secretes hormones (epinephrine and norepinephrine) during stress and emotions,
and adrenal cortex regulates salt and carbohydrate metabolism.
The pancreas regulates the level of sugar in the blood by producing insulin. It also plays a
Gonads
AP Test info…
•
Know the order of an action potential
fire
•
Afferent (sensory) vs Efferent (motor)
neurons
•
Sympathetic vs parasympathetic
•
Destruction of the myelin sheath
causes…
The
Brain
Methods to study the brain Old Brain (all parts with a
description)
Limbic system (all parts with
Reptilian “Old” Brain Structures
Brainstem the oldest part of the brain, beginning where the spinal cord swells and
Brain Stem
Medulla [muh-DUL-uh] base of the brainstem, controls
heartbeat and breathing.
Reticular Formation a nerve network in the brainstem that plays an important role in
Brain Stem
Thalamus [THAL-uh-muss]
the brain’s sensory switchboard, located on
top of the brainstem. It directs messages to the sensory areas in the cortex
and transmits replies to the cerebellum and
medulla.
Basal Ganglia
Pons functions as a bridge between regions and plays
a role in sleep and arousal
The “little brain”
attached to the rear of the brainstem. It helps
coordinate voluntary movements and
balance. It also plays a role in the formation
of procedural
memories (implicit or procedural memories,
EX. riding a bike)
Limbic System a doughnut-shaped
system of neural structures at the
border of the brainstem and
cerebrum, associated with emotions such as
fear, aggression and drives for food and sex. It includes the
hippocampus and the , amygdalae.
Amygdala
Amygdala [ah-MIG-dah-la] two
almond-shaped neural clusters linked to emotion of fear and
Hippocampus
•
The
hippocampus
is a structure in
the limbic system
which is
responsible for the
formation of most
new memories
(explicit memories,
EX. facts)
Hypothalamus
Hypothalamus lies below (hypo) the thalamus; directs several maintenance
activities like eating, drinking, body
temperature, and emotions. Helps
govern the endocrine system via the
New Brain
New Brain (cortex)
The four lobes and their functions
Language features of the brain
Copyright © Allyn & Bacon 2007
The Cerebrum
• Cerebrum –
Topmost layer of the brain; the bulbous cap over the limbic
system
• Cerebral cortex –
Thin gray-matter covering of the cerebrum; carries on
thinking and perceiving • Cerebral hemispheres –
The Cerebral Cortex
Structure of the Cortex (New
Brain)
Each brain hemisphere is divided into four lobes, separated by
prominent fissures. They are frontal lobes
(forehead), parietal lobes (top to rear head), occipital lobes
(back head) and
The 4 Lobes
Frontal
Lobe
• Concerned with
reasoning, planning, parts of speech and movement (motor cortex), emotions,
The Temporal Lobe
• Concerned with
perception and recognition of auditory stimuli (hearing) and memory
The Occipital Lobe
• Located at the back
of the brain, behind the parietal lobe and temporal lobe.
• Concerned with
The Parietal Lobe
Concerned with
perception of stimuli related to touch,
pressure,
Functions of the Cortex
Motor Cortex area at the rear of the frontal lobes controls voluntary movements.
Sensory Cortex (parietal cortex) receives information from skin surface and sense
Visual Function
Functional MRI scan shows the visual cortex activates as the subject looks at
Auditory Function
Functional MRI scan shows the auditory cortex is activate in
More intelligent animals have increased “uncommitted” or association areas of the
cortex.
Language
Aphasia is an impairment of language, usually caused by left hemisphere damage either to Broca’s area (impaired speaking) or
Specialization & Integration
Brain is sculpted by our genes but also by our experiences.
Plasticity refers to the brain’s ability to modify itself after some type of injury or
illness.
When we are young our brains are more plastic.
Bell Work
•
Are you a left brain person or a right
brain person?
•
How do you know?
•
Is there a difference
•
Today:
–
Review
–
Left vs. Right hemispheres
–
Split the Brain
–
Imaging techniques
Our Divided Brain
Our brain is divided into two hemispheres. Left hemisphere processes reading, writing, speaking,
mathematical, comprehension skills, and thus termed as
Splitting the Brain
A form of psychosurgery in which the two hemispheres of the brain are isolated by
cutting the connecting fibers (mainly those of the corpus callosum) between them.
Roger Sperry conducted research on this
procedure to help people suffering from grand mal seizuresCorpus Callosum
Split Brain Patients
With the corpus callosum severed, objects (apple) presented in the right visual field can
This is “Split Brain Joe”,
that is not Michael Gazzaniga
with him
B
B
The Brain
Techniques to Study the Brain
Brain lesion
experimentally
destroys brain tissue to study animal
behaviors after such destruction.
Phineas Gage
•
He was a railway worker who
was severely injured when a
13 pound metal rod was
driven through his skull in an
explosion
•
He recovered, but the damage
to the front lobes and the
severing of the connective
tissue to the limbic system
left him a changed person
•
Scientists have learned much
Electroencephalogram (EEG)
An amplified recording of the electrical waves sweeping across the brain’s
surface, measured by electrodes placed on the scalp. (shows functioning)
The CAT Scan
Computerized Axial
Tomography
• CAT scans use a series of X-ray beams passed through the head. The images are then
developed on sensitive film. This method
creates cross-sectional images of the brain and shows the structure of the brain, but not its function.
PET Scan
PET (positron emission tomography) Scan a visual display of brain activity that detects a
radioactive form of glucose while the brain performs a given
MRI Scan
MRI (magnetic resonance imaging)
uses magnetic fields and radio waves to produce computer-generated images that
distinguish among different types of brain
tissue
(shows structure)
fMRI produces images while performing a task
(reciting alphabet)
**(shows structure and function)**
Brain Organization &
Handedness
Is handedness inherited? Yes. Archival and historic studies to modern medical studies
point that right hand is preferred. This suggests, genes and/or prenatal factors
AP Exam stuff…
-What about the forebrain, midbrain,
hindbrain?
forebrain-
cerebrum, thalamus, and hypothalamusmidbrain-Limbic system
hindbrain-medulla, cerebellum, pons
***Often the midbrain, pons, and
medulla are referred to together as the
brainstem***
-Know the parts and their functions
-Understand the different scans, what
they
show
Neuron Review
•
What are the 3 main structures of all
Neurons?
•
What does myelin do?
•
How are axons and Dendrites different?
•
Afferent neurons (sensory)– Send
information from the body to the brain
•
Efferent neurons (motor)– Send
Neurotransmitter Review
• Low levels of this neurotransmitter may
result in depression and suicide. Serotonin
• Excess amounts of this neurotransmitter
may result in Schizophrenia Dopamine
• Due to it also being a hormone, this
neurotransmitter is also known as noradrenaline.
Norepinephrine
• Low levels of this neurotransmitter may be
Neurotransmitter Review
• Low levels of this neurotransmitter leads to
Parkinson’s disease. High levels???
Dopamine
• This neurotransmitter is used during muscle
contraction.
Acetylcholine
• What is the major inhibitory neurotransmitter?
GABA
• Lower levels of this neurotransmitter are
generally found in women.
Lobes of the Brain (Review)
• What are the four lobes of the human brain?
Frontal, Temporal, Occipital, Parietal
• Which is important for active through and
controlling impulsive behavior? Frontal
• Which one is responsible for your sense of
hearing?
Temporal
• Which one is responsible for your sense of
vision?
Occipital
• Which one is responsible for your sense of
Brain structure Review
• Connects the left and right hemisphere
Corpus Callosum
• Most of our brain is composed of this structure.
Cerebrum
• The outer ¼ inch of the cerebrum
Cortex
• Heartbeat, respiration, blood pressure
Medulla
• Balance and Coordination
Cerebellum
• Relay station for sensory information
