Unit 3 – Workings of Mind and Body Chapter 6 – Body and Behavior Chapter 7 – Altered States of Consciousness Chapter 8 – Sensation and Perception
Interesting Stats on Brain 100 billion cells, each with thousands of connections (up to 100,000). 1 cubic inch=10,000 miles of fibers, 100 million cells 1300 -1400 grams 350 – 400 grams -adult versus newborn brain
Key Concepts Brain Sensory Neuron Motor Neuron Skin receptors Interneuron Muscle Nervous systems function in sensory input, integration, and motor output. The nervous system is composed of neurons and supporting cells. Membrane potentials arise from differences in ion concentrations between a cell’s contents and the extracellular fluid. An action potential is an all-or-none change in the membrane potential.
Key Concepts Action potentials travel along an axon because they are self-propagating. Chemical or electrical communication between cells occurs at synapses. One neurotransmitter can produce different effects on different types of cells.
P e r i p h e r a l N e r v o u s S y s t e m S k e l e t a l A u t o n o m i c ( S o m a t i c ) S y m p a t h e t i c P a r a s y m p a t h e t i c Central Nervous System Peripheral Nervous System Key Concepts The symmetry of the nervous system is correlated with body symmetry. Vertebrate nervous systems are highly centralized and cephalized. The vertebrate peripheral nervous system has several components differing in organization and function.
Key Concepts The brainstem conducts data and controls automatic activities essential for survival. The cerebellum controls movement and balance. The thalamus and hypothalamus are prominent integrating centers of the forebrain. The cerebrum contains the most sophisticated integrating centers.
Enclosed by myelin sheath End in synaptic terminals that release neurotransmitters
The Dendrite Song! Axons send outNeurotransmittersTo the dendrites all aroundAcross the synapseJumps the impulseNew ideas can now abound. StimulationIs what the brain needsTo make dendrites stretch and grow. New connectionsMake us smarterIn what we think and what we know. Use your dendrites,Use your dendrites,To connect throughout your brainTake in info, analyze it,Grow some new onesUnrestrained. (sung to the tune of "Clementine“) Use your dendrites,Use your dendrites,To connect throughout your brain.Take in info, analyze it,Grow some new onesUnrestrained.
How are neurons organized? (158) Three types of neurons Afferent (Sensory) neurons Interneurons (Central Nervous System) Efferent (Motor) neurons
Neural circuits form from any combination of two or more of these
Simplest: Sensory and motor neurons – reflex arc
“The Reflex Arc”
Neurotransmitters: crossing the gap between neurons Chemicals that cross the synapse to relay the impulse to another neuron or an effector Examples: acetylcholine, norepinephrine, dopamine, serotonin, endorphins, amino acids, neuropeptides, gases
Major Divisions of Nervous System Central N.S. Brain Brainstem Spinal Cord Peripheral N.S. Somatic N.S. Autonomic -Sympathetic -Parasympathetic
Central Nervous System (CNS) Cephalized Centralized Integration and processing of information White matter – axons in the CNS Gray matter – cell bodies, dendrites, unmyelinated axons Central canal of the spinal cord Ventricles of the brain Cerebrospinal fluid (CSF) Meninges– protective connective tissue
PNS Transmits information to and from the CNS Components Both sensory and motor functions Paired cranial nerves (12) Paired spinal nerves (31) Ganglia Motor division Somatic nervous system Voluntary - signals to and from skeletal muscles Respond to external stimuli Autonomic nervous system Involuntary - Internal environment, smooth and cardiac muscles Sympathetic and parasympathetic divisions
Actions of the parasympathetic and sympathetic divisions of the Autonomic Nervous System (156-158) Sympathetic division Stimulation Flight/Fight Energy generation Parasympathetic division Calming Rest and repair Often have antagonistic actions Cooperate to maintain homeostasis
Structure and function of the vertebrate brain
Integrating centers in the cerebrum Right and left cerebral hemispheres Cerebral cortex Highly developed and convoluted in mammals Lobes with sensory areas and association areas, frontal lobe with motor cortex Basal nuclei – planning and learning movement sequences
Other roles of the cerebral cortex Language and speech Broca’s area Wernicke’s area Emotions Limbic system – amygdala, hippocampus, and olfactory bulb Laughing, crying, aggression, feeding, and sexuality Memory and learning Short-term: frontal lobe Long-term: amygdala and hippocampus Neurons may make new connections Consciousness Emergent property based on activity in many areas of the cortex
3 Divisions of the Brain Hindbrain – attached to spinal cord, automatic functions (breathing, heartbeat) and some voluntary (walking, facial movements) Midbrain – relay station b/t hindbrain/forebrain Forebrain – largest/most complex region -includes cerebrum – center for complex thought
A. Left Hemisphere Spoken language is one of the clearest differences between the two hemispheres. For most people, language functions are in the left hemisphere.
1. Broca’s Area Located in the frontal lobe, usually in the left hemisphere Responsible for the muscle movements of speech Damage to this area causes problems in expressing thoughts in spoken language
B. Right Hemisphere Spatial skills - being able to perceive or organize things in a given space, judge distance, etc. Relationships and emotions
Left Brain: language, math, reasoning Right Brain: emotion, relationships, music
C. Plasticity The ability of the brain tissue to take on new functions Greatest in childhood Important if parts of the brain are damaged or destroyed
Methods of Studying Brain Recording Stimulation Lesions Accidents Images
IV. Imaging Techniques CAT Scan: X-rays taken from different angles of the brain MRI: computer generated images of soft tissue in the brain EEG: electrodes on the scalp measure waves of electrical activity in the brain PET: a visual display of brain activity based on glucose (blood sugar)
Sex GlandsTestes (male)Ovaries (female) Adrenal Glands-Regulate carbohydrate and salt metabolism-Prepares the body for action
Heredity and Environment Genes and Behavior Heredity – Genetic transmission of characteristics from parents to their offspring Nature vs. Nurture Debate Twin Studies Viewed as the “Gold Mine” of the Nature vs. Nurture debate