Topic: Autobiographical Psychosocial History
tutorthammy
Brain_and_Behavior_Crot.ppt*
- About 100 billion neurons (nerve cells) in the human brain
- Neurons have many of the same features as other cells
- Nucleus
- Cytoplasm
- Cell membrane
- What makes neurons unique is their shape and function
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- Dendrites
- Carry information to the cell body from other neurons
- Cell Body (Soma)
- Contains nucleus
- Axon
- Carries information to the next cell
- Myelin Sheath
- Insulates the axon and speeds up the neural impulse
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- Sensory neurons
- Carry information from sensory systems to the brain
- Also referred to as afferent
- Motor neurons
- Carry information from the brain to muscles and glands
- Also referred to as efferent
- Interneurons
- Carry information between other neurons
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- Synaptic vesicles
- Sacs in terminal button that release chemicals into synaptic space
- Neurotransmitters
- Chemicals released by synaptic vesicles
- Receptor sites
- Location on receptor neuron for specific neurotransmitter
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- Acetylcholine (ACh)
- Released at the neuromuscular junction
- Plays an important role in arousal and attention
- Loss of ACh producing cells is linked to Alzheimer’s Disease
- Dopamine
- Affects neurons associated with voluntary movement
- Plays a role in learning, memory, and emotions
- Loss of dopamine-producing cells causes symptoms of Parkinson’s Disease
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- Serotonin
- Found throughout the brain
- Appears to sets an “emotional tone”
- Low serotonin levels are implicated in depression
- Endorphins
- Reduce pain by inhibiting or “turning down” neurons that transmit pain information
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- Most psychoactive drugs (and toxins) work by blocking or enhancing synaptic transmission
- Botulism
- Blocks release of ACh at the neuromuscular junction, causing paralysis
- “Botox” is botulism toxin used to prevent facial muscles from making wrinkles
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- Curare
- Can stun or kill prey quickly
- Blocks ACh receptors causing paralysis
- Antipsychotic medications
- Block dopamine receptors
- Reduces schizophrenic hallucinations
- Caffeine
- Increases the release of excitatory neurotransmitters by blocking the inhibitory neurotransmitter adenosine
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In 1848, Gage, 25, was the foreman of a crew cutting a railroad bed in Cavendish, Vermont. On September 13, as he was using a tamping iron to pack explosive powder into a hole, the powder detonated. The tamping iron—43 inches long, 1.25 inches in diameter and weighing 13.25 pounds—shot skyward, penetrated Gage’s left cheek, ripped into his brain and exited through his skull, landing several dozen feet away. Though blinded in his left eye, he might not even have lost consciousness, and he remained savvy enough to tell a doctor that day, “Here is business enough for you.”
- The brain can be changed, both structurally and chemically, by experience
- Rat studies show that an “enriched” environment leads to larger neurons with more connections
- Has also been shown in humans
- Recent research has uncovered evidence of neurogenesis, or the production of new brain cells, in human brains
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- Video Review – Neuroplasticity
- https://www.youtube.com/watch?v=MvpIRN9D4D4
- Central nervous system (CNS)
- Consists of the brain and spinal cord
- Peripheral nervous system
- Connects the CNS to the rest of the body
- Somatic nervous system
- Autonomic nervous system
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Central Nervous System
Brain
Spinal Cord
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- Medulla
- Controls breathing, heart rate, and blood pressure
- Pons
- Maintains the sleep-wake cycle
- Cerebellum
- Coordinates body’s movements
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- Thalamus
- Relays information from sensory receptors to the brain
- Hypothalamus
- Influences motivated behavior
- Regulates hunger, thirst, body temperature, and sexual drive.
- Directly involved in emotional behavior
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- Reticular formation
- Network of neurons found throughout the brain
- Serves to alert and arouse higher brain in response to incoming information
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- Ring of structures located between the central core and the cerebral hemispheres
- Important to learning and emotional behavior
- Hippocampus essential in formation of new memories
- Amygdala, together with the hippocampus, is important for regulating emotions
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- Occipital lobe
- Receives and processes visual information
- Temporal lobe
- Complex visual tasks such as face recognition
- Receives and processed auditory information
- Involved in balance, some emotions and motivations
- Some language processing
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- Parietal lobe
- Receives sensory information from body
- Involved in spatial abilities
- Frontal lobe
- Coordinated information from other lobes
- Controls voluntary movement, attention, setting goals, and expression of appropriate emotions
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- Corpus Callosum
- Fibers that connect the two hemispheres
- Allow close communication between left and right hemishphere
- Each hemisphere appears to specialize in certain functions
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- Complex cable of nerves that connects brain to rest of the body
- Carries motor impulses from the brain to internal organs and muscles
- Carries sensory information from extremities and internal organs to the brain
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- The spinal cord controls some protective reflex movements without any input from the brain
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Peripheral Nervous System
Somatic Nervous System
Autonomic Nervous System
Sympathetic Division
Parasympathetic Division
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- Consists of neurons that communicate between the body and the brain
- Afferent neurons
- Neurons that carry messages from sense organs to spinal cord
- Efferent neurons
- Neurons that carry messages from the spinal cord or brain to muscles and glands
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- Sympathetic division
- Most active when you are angry, afraid, or aroused
- Fight-or-flight response
- Increases heart rate and breathing
- Stops digestion
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- Parasympathetic division
- Calms body
- Produces effects opposite to those of the sympathetic division
- Reduces heart rate and breathing
- Restores digestion
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- Helps coordinate and integrate complex psychological reactions
- Endocrine glands secrete hormones into the bloodstream
- Hormones serve to organize the nervous system and body
- Hormones also activate behavior, such as sexual behavior
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- Thyroid gland
- Secretes hormones (primarily thyroxin) that control metabolism
- Parathyroid glands
- Control levels of calcium and phosphate which in turn controls levels of excitability
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- Pineal gland
- Secretes melatonin which regulates the sleep-wake cycle
- Pancreas
- Regulates blood-sugar levels
- Secretes insulin and glucagon
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- Pituitary gland
- Referred to as the “master gland” because it regulates many other glands
- Gonads
- Ovaries and testes secrete estrogens and androgens
- Adrenal glands
- Secretes hormones in reaction to stress
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- Heredity - transmission of trait from one generation to next
- Chromosomes
- Pairs of thread like bodies that contain genes
- Deoxyribonucleic acid (DNA)
- Organic molecule arranged in a double-helix
- Contains the “code of life”
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- Study of behavior from a genetic perspective
- Animal behavior genetic studies include:
- Strain studies
- Selection studies
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- Family studies
- Assume that close family members share more of a trait than non-relatives
- Used to assess the heritability of psychological disorders or traits
- Twin studies
- Used to determine how heritable a trait or disorder may be
- Identical twins would have highest heritability
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- Adoption studies
- Used to assess the influence of environment
- Molecular genetics
- Direct study of the genetic code
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- Study of biological origins of behavior could lead to genocide and eugenics aimed at eliminating certain types of people
- Could also be used to create new categories of people, such as people bred to be good soldiers or manual laborers
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