Transcript neuroanatomy

Introduction to Psychology
Neurology
Plan for Today
•
•
•
•
Biological bases of behavior
Communication in the nervous system
Organization of the nervous system
Researching the brain
Components of the Neuron
– Dendrites: receive
information from other
neurons
– Cell body: creates transmitter
molecules
– Axon
• Myelin insulates the nerve cell,
speeds up conduction of nerve
messages
• Terminal buttons of the axon
release transmitter
© 2002 John Wiley & Sons, Inc.
Graded Potentials
• Stimulation of the nerve
membrane can open ion
channels in the membrane
• NA+ ions flowing in will
depolarize the membrane
(movement from -70 mV to
say -60 mV
• K+ ions flowing out of
membrane will hyperpolarize
the membrane (-70 mV to
say -90 mV)
© 2002 John Wiley & Sons, Inc.
The Action Potential
• Graded potentials are generated at the dendrites and are
conducted along the membrane to the axon hillock
• If the summated activity at the axon hillock raises the
membrane potential past threshold, an action potential
(AP) will occur
• During the AP, NA+ ions flow into the cell raising the
membrane potential to +40 mV, producing the spike
– The restoration of the membrane potential to -70 mV is
produced by an opening of channels to K+
– The AP is conducted along the axon toward the terminals
© 2002 John Wiley & Sons, Inc.
Details of the Synapse
© 2002 John Wiley & Sons, Inc.
Neurotransmitters
• Acetylcholine (Ach)
• Monoamines:
- epinephrine and norepinephrine
- serotonin
- dopamine
• GABA
• Glutamate
Overview of the Nervous System
© 2002 John Wiley & Sons, Inc.
Autonomic Nervous System
• The Autonomic Nervous System (ANS)
has two divisions:
– Sympathetic: Emergency system
– Parasympathetic: Vegetative functions (e.g.
digestion)
• The two systems often act in opposition
(as in the control of heart rate)
• Can act in concert (as in the control of
sexual reflexes)
© 2002 John Wiley & Sons, Inc.
Autonomic Nervous System
© 2002 John Wiley & Sons, Inc.
Midline View of Human Brain
Medulla: Controls heart rate, respiration
Cerebellum: Coordinates smooth movements, balance, and posture
Pons: Involved in the control of sleep
© 2002 John Wiley & Sons, Inc.
Limbic System Functions
• Septal area is involved in pleasure and in
relief from pain
• Amygdala is involved in learning and
recognition of fear
• Hippocampus is involved in memory
© 2002 John Wiley & Sons, Inc.
Cerebral Cortex
• Functions of cerebral cortex:
– Provides for flexible control of patterns of
movement
– Permits subtle discrimination among complex
sensory patterns
– Makes possible symbolic thinking
• Symbolic thought is the foundation of human
thought and language
© 2002 John Wiley & Sons, Inc.
The Cortical Lobes of
the Human Brain
© 2002 John Wiley & Sons, Inc.
Frontal Lobe Damage and Personality
• Frontal lobes are involved in movement,
attention, planning, memory, and personality.
• Frontal lobe function in personality is evident in
the case of Phineas Gage
– Gage suffered frontal lobe damage after an accident
involving a dynamite tamping rod
– Gage was a railroad supervisor prior to the damage;
after the damage he became childish and irreverent,
could not control his impulses, and could not
effectively plan.
© 2002 John Wiley & Sons, Inc.
Cerebral Lateralization
• The structures of the cortex and sub-cortex
appear to specialize in function:
– Hemispheric Specialization
• Left hemisphere is dominant for language, logic, and
complex motor behavior.
• Right hemisphere is dominant for non-linguistic functions
including recognition of faces, places, and sounds (music)
• The hemispheric specializations are evident from studies of
– Damage to one hemisphere (I.e. Broca’s area)
– Split-brain subjects
© 2002 John Wiley & Sons, Inc.
The Split-Brain Study
• Information from the one visual field is usually
transmitted to the opposite visual cortex
• The corpus callosum serves to integrate the two
hemispheres
• Cutting the corpus callosum can result in
information reaching only one hemisphere
– Language is a left-hemisphere function
– Information reaching the left hemisphere will be reported
by the subject, but not information reaching the right
hemisphere
© 2002 John Wiley & Sons, Inc.
Split-Brain Studies
(Figure adapted from Gazzaniga, 1967)
© 2002 John Wiley & Sons, Inc.
The Endocrine System
• Glands that secrete hormones into the
bloodstream to help control bodily
functioning
• Hypothalmus connected to pituitary gland
(master gland)
- adrenal glands = fight or flight
- Gonads = secondary sex characteristics
Endocrine Systems
• Endocrine glands release
hormones into blood stream
– Have effects at diffuse target sites
throughout the body
– Hormones bind to receptors
– Hormones can have organizational
effects (permanent change in
structure and function)
– Hormones can have activational
effects:
• Lack of testosterone reduces sexual
behavior
© 2002 John Wiley & Sons, Inc.