Communication
• Arousal States
• Neurons
• Neurotransmitters
• Experience and Plasticity
True or False?
T/F The human brain is larger than that of any other animal.
T/F A single cell can stretch all the way from your spine to your toe.
T/F Messages travel in the brain by means of electricity.
T/F A brain cell can send out hundreds of messages each second,
and manage to catch some rest in between.
T/F Fear can give you indigestion.
T/F If a surgeon were to stimulate a certain part of your brain
electrically, you might swear that someone hade stroked your leg.
Nervous System
Our nervous system consists of two main bodies:
• Central Nervous System
• Peripheral Nervous System
“The more flexible we can form associations the more
humanlike we are. This is what makes us special.”
(Remark considering left frontal lobe specialization)
Nervous System
Central Nervous System: (CNS)
• Brain
• Spinal cord: Collection of neurons and
supportive tissue running from the base
of the brain down the center of the back,
protected by a column of bones.
– Spinal reflexes are automatic
Peripheral Nervous System: (PNS)
• All portions of the nervous system outside the brain and spinal
cord.
• Sensory Nerves (Afferent Impulses)
• Motor Nerves (Efferent Impulses)
• Contains:
– Somatic Nervous System
– Autonomic Nervous System
Somatic and Autonomic Nervous Systems
Somatic Nervous System: (connects)
 Sensory receptors
 Skeletal muscles
• AKA: Skeletal Nervous System
Autonomic Nervous System:
 Regulates the internal organs and glands.
• Contains:
– Sympathetic Nervous System
– Parasympathetic Nervous Systems
Arousal States
Sympathetic Nervous System (SNS):
Physical Changes
Increase in norepinephrin
Pupil dilation
Increased heart-rate
Sweating
Decrease in digestion
Vein dilation in periphery
Pilo erection
Elements
All elements necessary for survival
Fight-or-Flight instinct
Activated during anxiety and stress
Parasympathetic Nervous System (PNS):
Physical Changes
Increased digestion
Opposite of SNS
Elements
Conserves energy
Tired/Relaxed
Nervous System
Nervous System
Spinal Cord Reflex Not regulated by the brain.
Neurons
Neurons:
• Specialized nerve cell that receives, processes, and
transmits information to other cells in the body.
Neurons
Three Types of Neurons:
• Sensory (afferent) neurons: Carry messages
from sense organs to the spinal cord or brain.
• Interneurons (association neurons): Carry
messages from one neuron to another.
• Motor (efferent) neurons: Carry messages
from the spinal cord or brain to the muscles
and glands.
Neurons
Structure:
•
Soma: cell body, processing center
– Nucleus: contains DNA
•
Neurites: structures that extend from the soma
– Dendrites: receives information and sends to soma
– Axon: transports messages from the soma
•
Dentrite Divisions:
– Spine: receives NT message
• Also known as a receptor site
•
Axon Divisions:
– Hillock: initiates action potential
– Myelin Sheath: fatty covering on axon
– Node of Ranvier: unmyelinated space
– Axon Terminal: sends message to terminal buttons
– Terminal Button: site where vesicles are released
•
Terminal Button Divisions:
– Synaptic Vesicles: carries NT to synapse
– Neurotransmitter: chemical messenger
– Synapse: Space between buttons and spines
• Also known as synaptic gap or synaptic cleft.
Neurons
Neurons
• In what ways are neurons
like other cells?
• Which features are
unique to neurons?
Neurons
Presynaptic Neruon: Sends the message.
Postsynaptic Neuron: Receives the message.
Neurons
Neurons
Glia Cells: (Support Cells)
•
CNS
– Astrocytes
• Phagocytosis
• Blood Brain Barrier
– Oligodendrocytes
• Myelination
• Increase speed and insulate
– Ependymal
• Line walls of the ventricles
• Create cerebrospinal fluid
– Endothelial
• Help with BBB
– Radial
• Aide in neuronal migration
•
PNS
• Schwann
Neurotransmitters
Chemical messengers in the brain.
Catecholamines: Norepinephrine, Epinephrine, Dopamine
Indoleamines: Serotonin
Neurotransmitters
Neurotransmitters
Locations of production sites for major NT’s:
• Dopamine- Substantia Nigra
• Norepinephrine- Locus Coeruleus
• Serotonin- Raphe Nuclei
Experience and Plasticity
Endorphins and
Hormones
Endorphins:

Pain reduction, pleasure, contentedness, memory.

Endogenous opiate peptides.
Hormones:

Affects the functioning of organs.

Released directly into the blood stream.

Promote growth, increase digestion, and regulate metabolism.

Secreted by organs called glands.

Produced primarily in endocrine glands.

Melatonin: Secreted by the pineal gland, helps regulate daily
biological rhythms and promotes sleep (seasonal depression).

Adrenal Hormones: Produced by adrenal glands, emotion and
stress.

Sex Hormones: Secreted in gonads (testes and ovaries), produce
androgens (testosterone) and estrogens (progesterone).
Genetics
•
Traits: Characteristics on which organisms differ.
•
Heredity: Transmission of traits from one generation to the next.
•
Genes: Elements that control the transmission of traits; they are
found on the chromosomes.
•
Chromosomes: Pairs of threadlike bodies within the cell nucleus
that contain the genes.
•
Deoxyribonucleic acid (DNA): The main ingredient of
chromosomes and genes that forms the code for all genetic
information.
Genetics
• Dominant: Member of a gene pair that controls
the appearance of a certain trait.
• Recessive: Member of a gene pair that can
control the appearance of a certain trait only if it
is paired with another recessive gene.