Parts of a Neuron

Neuron- brain cell in nervous system

Dendrites- branching extensions that receive and integrate messages conducting impulses

Cell Body- part of neuron that contains nucleus

Axons- segmented neuron extension that passes messages through branches to other neurons or muscles

Myelin Sheath- tissue layer encasing axons, enables transmission speed when hopping from one to the next

Glial Cells- cells in nervous system that support, nourish, and protect neurons (learning, thinking and memory)

Action Potential- neural impulse, electrical charge that travels down axon; depolarized, more sodium than potassium, when it reaches terminals, triggers release of NTS

Resting Potential- polarized neural impulse with equal amounts of sodium and potassium

• Energy travels down axon to the terminals where NTS are released into a synapse so that a receiving neuron can be told to fire

Refractory Period- resting period that occurs after neuron has fired, subsequent action potentials cannot occur until axons return to resting state

Threshold- level of simulation required to trigger neural impulse

All or None Response- a neurons reaction of either firing or not firing

Synapse- junction between axon tip of sending neuron and dendrite or cell body of receiving neuron; tiny gap is called synaptic gap

Neurotransmitters- chemical messengers that cross synaptic gap between neurons

• NTS travel across synapse and bind to receptor sites on receiving neuron

• released by sending neuron

• influences if neuron will generate neural impulse

Reuptake- NTS re-absorption by sending neuron, drift away, or broken down by enzymes; recycled, kept in synapse if blocked

Nuero genesis- when one neuron dies, dendrites can regenerate

Endocrine System

• the bodys slow chemical communication system, communication carried out by glands that release hormones into the body

Hormones- chemical messengers that influence sex, hunger and anger

In dander situations, ANS orders adrenal glands to release adrenaline to start fight or flight

Pituitary gland- most influential controlled by hypothalamus

• releases growth hormones and oxytocin

• directs other glands to release hormones, then influences brain/behavior

• called a maestro gland

  brain→pituitary→glands→hormones→brain/body

Parts of Endocrine System-

• hypothalamus - controls endocrine system, thirst/hunger, homeostasis, sex drive

• pituitary gland

• parathyroids

• thyroid gland

• adrenal gland

• pancreas

• testes/ovary

Neurotransmitters

• chemical messengers that travel across a synapse and bind to dendrites receiving sites to produce a neural impulse

Agonist- Increase NT action, increase production and release

Antagonist- Decrease NT action, decrease production and release

Acetylcholine, enables muscle movement, learning and memory,

• too much is good memory,

• too little is Alzherimers

Dopamine- influences movement, pleasure, reward, attention and emotion

• too much is schizophrenia

• too little is tremors and Parkinsons

Endorphins- influence perception of pain or pleasure

• too much suppresses pain, no pain

• too little is intense pain, decrease of arousal

Gaba- inhibitory NT

• too much eating disorder

• too little is seizures and tremors

Glutamate- exciatory, memory

• too much overstimulates brain, migranes and seizures

• too little, slows development

Norepinephrine- controls alertness and arousal

• too much bipolar hyperactivity

• too little depresses mood and energy level

Seerotonin- affects balanced sleep, mood, hunger, thirst and arousal

• too much is manic, adhd

• too little is depression

Melatonin- sleep circadian rhythum, released with no light

• too much is tiredness, seasonal affective disorder

• too little is insomnia

Substance P- pain perception and immune response

• too much is chronic pain

• too little is no pain

Brian Structures

The brainstem

Medulla- heart beat and breathing, base

Pons- movement and controls sleep

Reticular Formation- nerve network from spinal cord to thalamus arousal, alertness, awakeness

Thalamus- sensory control center, receives info and routes info to brain region, all senses except scent

Cerebellum- voluntary movement, balance, skill, memory, mini brain

The Limbic System

• part of the brain involved in behavioral and emotional responses, emotions, drives and memory

Amygdala- agression and fear, reduce fear and arousal with injuries

Hypothalamus- directs maintenance activities and governs endocrine, reward center for desired behaviors ex: sex, eating, drinking, body temp,

Hippocampus- conscious new memories, new info of facts and events, size decrease as age increase

Thalamus- all senses except scent

Corpus Callosum- connects the 2 sides, and communicates between the two

Cerebral Cortex

• interconnected neural cells covering hemispheres, control and process center, increase capacity for learning, thinking enables adaptation

Frontal Lobe- behind forehead; linguistic, muscle movement, plans and judgement

Parietal Lobe- top/read; sensory input for touch and body position

Occipital Lobe- back of head; receive info from visual fields

Temporal Lobe- above ears, auditory and language processing from opposite ears

Wernickes Area- speaking with little sense, running words together

Brocas Area- can’t speak correctly but move muscles, can’t get words out

Split Brain

Responses to Damage

1. severed brain and SC don’t regenerate

2. some functions are preassigned to specific areas

   • unused brain areas can extend to increase space of others

3. brain will attempt self repair by reorganizing or extending areas but can also neurogenesis (producing new neurons)

Divided Brains

• left hemisphere damage effects: reading, writing, speaking, math, etc

• right hemisphere damage effects: attention, perception, artistic

Split Brain

Result of splitting the corpus callosum, last measure to end epilepsy (Sperry and Gazzaniga)

• information doesn’t get shared between the two

Left Hemisphere

• controls everything on right side

• takes in right visual field

• analytic and procedural

• writing

• language

• logic

• linear thinking

Right Hemisphere

• controls left side of body

• left visual field

• emotional detection and interpretation

• spatial awareness

• music

• creativity and imagination

• holistic

Functions of Cortex

Motor Functions

Motor Cortex- region at back of frontal lobe (at ears) movement with application

• body areas requiring precise control occupy more amount of cortical space

Order of stimulus: screen with images→imagine→brain signal from motor cortex →message sent →stimulates muscles

Sensory Functions

Somatosensory Cortex- front of parietal lobes that specialize in receiving info from skin senses

• more sensitive area, increase cortex area

• visual cortex in occipital that send to other areas for words, emotions, memory

• auditory cortex in temporal that travel from one to the other

Association Areas

- Areas in cerebral cortex not involved in motor or sensory, but learning, memory, speaking and thinking

• prefrontal cortex in frontal lobes, enables judgement, planning, new memories, and personality

• with injury moral compass is separated from actions

• underside of right temporal lobe is to recognize faces

Functional Connectivity- communication among brain areas and neural networks

The Nervous System

• the bodys communication network with neurons and NTS that take info and make decisions

CNS (central)- brain, spinal cord, decision maker

PNS (peripheral)- gather info, transmit CNS decisions to other parts

Sensory neruons- carry messages from tissue to CNS

Motor neurons- instructions from CNS to muscles

Interneurons- where info is processed (CNS)

Peripheral Nervous System

Somatic- voluntary control of skeletal muscles (tapping shoulder leads to head turn)

• breaks into sensory input, and motor muscles

Autonomic- controls glands and organs, self regulating, automatic

• breaks into sympathetic and parasympathetic

Sympathetic

Arousing, “fight or flight”

• pupils dilate

• heart beat accelerates

• stomach and pancreas inhibit digestion

• liver releases glucose

• adrenal glands release epinephrine

• bladder relaxes

Parasympathetic

Calming, “rest and digest”

• pupils contract

• heart slows

• stomach and pancreas allow digestion

• gallbladder stimulates bile

• bladder contracts

• genitals allow blood flow

Central Nervous System

Brain- individual neurons form neural networks with nearby neurons to have short and fast connections

Spinal Cord- connects PNS and brain,

Reflexes- automatic response to stimuli, come from sensory and motor neurons using inter neuron to communicate

• simple reflexes are quick, only gets sent to SC not the brain, ex: moving hand away from heat

Neuroplasticity and Tools

Phrenology- studying bumps on the head leads to

Neuroplasticity- the brains ability to change (usually during childhood) by reorganizing after damage or with new pathways, allows adaptation

Biological Psychology- links between biological and psychological processes helps us discover:

1. our experiences wire adaptive brain

2. neurons conduct electricity and talk to one another sending chemical messages over synapses

3. specific brain systems serve specific functions

4. integrate info in different brain systems to construct experiences of sight, sound, meanings, memories, pain and passion

Use biopschosocial approach that incorporate biological, psychological and social-cultural systems to see how they shape behavior and mental process

Biological Influences

• genetically influenced traits

• gnetic mutations

• natural selection

• genes respond to environment

Psychological Influences

• learned fears and expectations

• emotional responses

• cognitive processing

• perceptual interpretations

Social Cultural Influences

• presence of others

• cultural, societal, family expectations

• peer/group influences

• compelling models (media)

Tools of Discovery

Lesion- selectively destroying clusters of normal or defective brain cells, observing the effect on brain function

• can also stimulate parts to see effect

• electrodes can detect where info is going

• optogenics- controlling activity of individual neurons

EEG- records waves of electrical activity across brains surface to see where coming from

MEG- measures magnetic fields of speed and strength to see how tasks influence brain activity

CT- x-ray photos to see brain damage

PET Scan- shows brain consumption of glucose, where most active areas are when shown/doing something

MRI- magnetic and radio waves to see soft tissue sizes, ventricles, and damage

fMRI- shows brain function and structure, blood goes where active, increase oxygen blood flow to active, enable which areas are most active, continuous MRI scans