psych unit 2

Franz Gall

Franz Gall

proposed phrenology

Phrenology

the detailed study of the shape and size of the cranium as a supposed indication of character and mental abilities.

Neurons

a nerve cell; the basic building block of the nervous system

Cell body (soma)

the part of a neuron that contains the nucleus; the cell's life-support center

dendrite

the bushy, branching extensions of a neuron that receive and integrate messages, conducting impulses toward the cell body. branches off the cell body

axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands. passes messages through its terminal branches. extends off the dendrite.

myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next. As the myelin sheath is laid down up to about age 25, neural efficiency, judgment, and self-control grow. If the myelin sheath degenerates, multiple sclerosis results.

multiple sclerosis

communication to muscles slows with eventual loss of muscle control.

glial cells

cells in the nervous system that support. nourish, and protect neurons; they also play a role in learning, thinking, and memory.

action potential

a neural impulse, a brief electrical charge that travels down the axon. a neuron sends a message by firing an impulse, "action potential". neuron stimulation causes the electrical charge to go above -55 mV, triggering the action potential.

the temporary inflow of positively charged ions - neural impulse

resting potential

positively charged sodium ions are in the fluid outside an axons membrane and large, negatively charged protein ions and smaller positively charged potassium ions in the fluid's interior (mostly negative)

Depolarization

the loss of the inside/outside charge difference. when a neuron fires, positively charged sodium ions (attracted to the negative interior) flow through the newly opened axon channels, causing the loss of the difference in charges. depolarization cases more axon channels to open.

excitatory neurotransmitters

like pushing a neuron's gas pedal; increases the likelihood of an action potential (Glutamate)

inhibatory neurotransmitters

chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing; like pushing the neuron's brake. decreases the likelihood of an action potential. GABA

threshold potential

-55mV

• The minimum membrane potential must be reached in order for an action potential to be generated.

• If the excitatory signals exceed the inhibitory signals by a minimum intensity, the combined signals trigger an action potential.

  
  
  

Refractory period

the time following an action potential during which a new action potential cannot be initiated. the neuron can't fire until after it returns to its resting state.

all or none response

a neuron's reaction of either firing (with a full-strength response) or not firing. increasing the level of stimulation above the threshold will not increase the intensity of the reaction. a strong stimulation can trigger more neurons to fire and to fore more often, but does not affect the action potential's strength and speed.

synapse

the gap between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons. when released by the sending neuron, neurotransmitters travel across the synapse and bind to the receptor sites on the receiving neuron.

unlocks channels at the receiving site and either excite or inhibit the receiving neuron.

reputake

When a sending neuron reabsorbs any leftover neurotransmitters to be reused. leftover neurotransmitters can also be broken down by enzymes.

Agonist molecules

increases neurotransmitter activity by:

• unlocks channels at the receiving site and either excite or inhibit the receiving neuron.

• blocking reuptake

• -or be similar enough (mimics) to a neurotransmitter to bind to its excitatory/inhibitory effects

  
  

Antagonist molecules

Decreases a neurotransmitter's action by blocking production or release

-enough like natural neurotransmitters to occupy its receptor site and block its effect but not similar enough to stimulate receptor and produce effects

Acetylcholine

functions: memory, movement (muscle contraction), attention/arousal, learning

• oversupply: muscle convulsions

• Undersupply: memory loss (Alzheimer's) and paralysis

Dopamine

Functions: movement, pleasure/reward, learning, attention

• Oversupply: schizophrenia (treated by antagonist drugs that block dopamine)

• undersupply: Parkinson's disease (tremors/decreased mobility)

Serotonin

functions: mood, sleep, alertness, appetite, anxiety

• undersupply: depression, sleep disorders, aggression

• *anti depressants are agonists

Norepinephrine

functions: arousal/attention, neurotransmitter and hormone, sympathetic nervous system (activates fight or flight)

• oversupply: anxiety, panic attacks, mania

• undersupply: depression

  *adrenal glands release this and epinephrine

GABA

functions: sleep, relaxation

• undersupply: seizures, insomnia, anxiety disorders, Huntington's disease

• *MAJOR INHIBATORY NUEROTRANSMITTER

Glutamate

functions: memory, learning

• oversupply: migraines/seizures, possible CNS disease

• *MAJOR EXCITATORY NEUROTRANSMITTER

endorphins

functions: inhibit pain (released in response to pain/vigorous exercise) and pleasure, can be either neurotransmitter or hormone

• oversupply: higher pain threshold, runner's high

• undersupply: lower pain threshold, lowered natural production due to use of opiates (results in withdrawal cravings)

neurotransmitters

*produced in CNS

hormones

*produced by pituitary/adrenal glands:

Nervous system

the body's electrochemical communication network consisting of all the nerve cells of the peripheral and central nervous system. RELEASES NEUROTRANSMITTERS VERY FAST!!

CNS (central nervous system)

the spinal cord and brain

spinal cord

two way information highway connecting the peripheral nervous system and the brain

PNS (peripheral nervous system)

the sensory and motor neurons that connect the CNS to the rest of the body. two divisions are autonomic and somatic

nerves

bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs

Motor neurons

Carry outgoing information from the brain and spinal cord to the muscles and glands (Exits CNS)

-Efferent

sensory neurons

neurons that carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord (CNS). enters CNS.

-afferent

interneurons

neurons within the brain and spinal cord; they communicate internally and process information between the sensory input and motor output

somatic nervous system

PART OF PNS. controls the body's skeletal muscles. also called the skeletal nervous system. enables VOLUNTARY control of skeletal system.

autonomic nervous system

PART OF PNS. controls the glands and muscles of the internal organs (ex heart). two divisions are sympathetic and parasympathetic. INVOLUNTARY movement

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy. deaccelerates heartbeat, lowers blood pressure, stimulates digestion, increases saliva production, processes waste

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations. FIGHT OR FLIGHT. accelerates heartbeat, raised blood pressure, inhibits digestion, perspiration, pupils dilated, inhibits saliva

ascending neural fibers

send up sensory information

descending neural fibers

send back motor-control information

reflexes

simple, automatic responses to sensory stimuli, such as the knee-jerk response, involves singular sensory neuron and singular motor neuron

-simple reflexes occur only in the spinal cord before the information reaches the brain

endocrine system

the body's "slow" chemical communication system; a set of glands that SECRETE HORMONES into the bloodstream. slower than nervous system

hypothalamus

gland of endocrine system; brain region that controls the pituitary gland

pituitary gland

regulates growth hormones and oxytocin, and controls other endocrine glands.

thyroid gland

affects metabolism

Parathyroid

helps regulate the level of calcium in the blood

adrenal glands

secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress. autonomic nervous system orders these glands.

pancreas

Regulates the level of sugar in the blood

testis

secretes male sex hormones

ovary

secretes female sex hormones

leison

tissue destruction

EEG (electroencephalogram)

An amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp.

-most commonly used for epilepsy and seizures, analyzes brain as a whole

MEG (magnetoencephalography)

measures magnetic fields from the brain's natural electrical activity

CT/CAT (computed tomography)

a series of X-RAY photographs of the brain taken from different angles and combined by computer to create an image that represents a slice through the brain. SHOWS STRUCTURE, can reveal brain damage.

PET (positron emission tomography) scan

a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task. INJECTS GLUCOSE!!! SHOWS ACTIVITY!

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy. more accurate than CT. again, SHOWS STRUCTURE

fMRI

same thing as MRI but shows BOTH FUNCTION AND STRUCTURE

shows structure

CT, MRI, fMRI

shows activity/function

EEG, MEG, PET, fMRI

Brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions

medulla

the base of the brainstem; controls heartbeat and breathing

pons

Sits above medulla and helps coordinate movement and controls sleep

thalamus

the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

reticular formation

a nerve network in the brainstem that plays an important role in controlling arousal. helps control arousal and filters incoming stimulus -responsible for sleep-wake cycle (REM)

Cerebellum

the "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance

limbic system

neural system located below the cerebral hemispheres; associated with emotions and drives

Amyglada

part of limbic system that plays key roles in fear, excitement, arousal, and aggression

Hypothaalmus

Responsible for thirst, hunger, sex drive, temperature, sleeping. helps govern endocrine system via pituitary gland, linked to emotion and reward

Hippocampus

helps process explicit (conscious) memories for storage. decreases in size/function as we get older.

synaptic vesicles

Tiny pouches or sacs in the axon terminals that contain chemicals called neurotransmitters.

anti depressants

block reuptake of serotonin so there is more serotonin neurotransmitters in the synapse.

Cerebral cortex

intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control/information processing center

frontal lobes

lies behind the forehead, involved in speaking, muscle movement, making plants and judgement

parietal lobe

lying at the top of the head towards the rear, receives sensory input for touch and body position

occipital lobe

back of the head, includes areas that receive information from the visual fields

temporal lobe

lies above the ears, includes auditory areas, each receiving information from the opposite ear

motor cortex

controls VOLUNTARY movement (rear of frontal lobe)

somatosensory (sensory) cortex

registers information from the skin senses and body movement (left hemisphere section receives input from the body’s right side)

auditory cortex

receives information from the ears (part of temporal lobe)

visual cortex

receives information from the eyes (in occipital lobe)

association areas

areas of the cerebral cortex that are not involved in primary motor/sensory functions; rather they are involved in higher mental functions such as learning, remembering, thinking, and speaking.

prefrontal cortex

forward part of the frontal lobe that enables judgement, PLANNING, and processing new memories

Brocca’s area

language center located in the left frontal lobe, involved in expressive language

wenicke’s area

language center located in the left temporal lobe, involved in receptive language

plasticity

our brain adjusting to new experiences. the brain changes, especially during childhood, by reorganizing after damage or by building new pathways based on experience

neurogenesis

producing new neurons in an attempt to self-repair (either this or plasticity)

corpus callosum

neural fibers connecting the two hemispheres of the brain and carrying messages between them

split brains

a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

visual field

the right sides of both retinas gather information from the left side of what you are looking at, vice versa. in each eye, information from the left half of your field of vision goes to your right hemisphere, and information from the right half of your vision field goes to your left hemisphere

split brain vs intact brain

intact: information is transferred across the corpus callosum from both hemispheres of the brain

split: cross-transference does not occur

left hemisphere

• speaking and language

• brocca’s and wernicke’s (expressive and receptive language)

• math calculations

• making literal interpretations

• controlling right side of body

right hemisphere

• perpetual tasks

• making inferences

• modulating speech

• visual perception

• recognition of emotion

• controlling left side of body

consciousness

our subjective awareness of ourselves and our environment

cognitive neuroscience

combines the study of brain activity with how we learn, think, remember, and perceive