Chapter 3 Biology Part 2

Psychology 0010 with Welch at Brown University

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By: Noni Wang
Created: 2011-02-19
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Interneurons

Neurons that communicate only with other neurons.

-Most connect neurons in one part of the brain with neurons in another part, others receive info from sensory neurons and transmit it to motor neurons for action.

-Most common kind of neuron in the brain

ex: pain

Neural Communication

2-step process

1. an impulse travels 1 way from dendrites along the axon and away from the soma (AP)

2. releases chemicals into cleft, messages another neuron (neurotransmission)

Action Potential

The Impulse of positive charge that runs down an axon

-axon membrane separates the fluid inside form outside and is somewhat permeable: lets only certain particles move through it

Ions

electrically charged particles that moves in the fluid inside and outside the cell contains

Negatively charged ions

Anions

Channels in the membrane

Allows ions to flow back and forth from between the inside and outside of the cell

-responsible for membrane permeability

Voltage-dependent channels

Channels or passages that will open only when certain electrical conditions are met or when an impulse is being transmitted

Resting Potential

The difference in electrical charge between the inside and outside of the axon when the neuron is at rest

Different Charges in the Cell

There is a difference in charge inside the cell compared to outside the cell

-In the resting state: no impulse is being transmitted--an excess of negtively charged particles inside the axon

-Fluid outside the axon has + charge

Potential

The charge difference between the inside and outside of the neuron

Resting Potential

The difference in electrical charge between the inside and outside of the axon when the neuron is at rest

-In the resting state, electrical charge diff. is -70 millivolts

Depolarization

If an incoming impulse increases the positive charge inside the neuron to a certain threshold, the neuron becomes depolarized and fires an action potential

Refractory Period

The span of time, after an action potential has been generated, when the neuron is returning to its resting state and the neuron cannot generate an action potential

Steps of refractory period

1. resting potential is -70mV

2. with sufficient depolarization, voltage-dependent sodium channels open and sodium ions flood into the neuron

3. Influx of + sodium ions raises the membrane potential = AP

4. When +40 mV is reached, sodium channels close and potassium channels open; outward flow of positively charged potassium ions

Sodium Channels

After depolarization, the top of axon opens and +charged sodium ions pour into the cell

-leads a brief spike in +, raises membrane potential

All-or-None Principle

The idea that once the threshold has been crossed, an action potential either fires or it does not; there is no halfway

Synaptic Vesicles

Tiny sacs in the terminal buttons that contain neurotransmitters

-they bind with receptors in the receiving, or post-synaptic neuron in a lock-and-key type of arrangement

-each binds only with a specific receptor

Enzymatic Degradation

A way of removing excess neurotransmitter from the synapse, in which enzymes specific for that neurotransmitter bind with the neurotransmitter and destroy it

Graded Potentials

Small changes in membrane potential that by themselves are insufficient to trigger an action potential

-some created to decrease the likelihood that a neuron will fire

-increase or decrease the likelihood of an action potential

Reuptake

A way of removing excess neurotransmitter from the synapse, in which excess neurotransmitter is returned to the sending, or presynaptic, neuron for storage in vesicles and future use

GABA

A major inhibitory neurotransmitter in the brain that tells postsynaptic neurons not to fire; slows CNS activity and is necessary to regulate and control neural activity

The Soma in the postsynaptic neuron

Integrates the graded potentials in the post-synaptic neuron

Dopamine

A neurotransmitter released in response to behaviors that feel good or are rewarding to the person or animal; also involved in voluntary motor control

-Dopamine-producing neurons die in Parkinson's disease

Acetylcholine

A neurotransmitter that controls muscle movement and plays a role in mental processes such as learning, memory, attention, sleeping, and dreaming.

-Decrease in ACh may contribute to Alzheimer

Epinephrine

Also known as adrenaline, a neurotransmitter that arouses bodily systems such as increasing heart rate

Serotonin

A neurotransmitter with wide-ranging effects: involved in dreaming and in controlling emotional states, especially anger, anxiety and depression

Norepinephrine

A neurotransmitter that plays an important role in the sympathetic nervous system, energizing bodily systems and increasing mental arousal and alertness

-Leads to physical arousal like increased heart rate

-ADHD lacks norepinephrine

Neurotransmitters

Found only in the brain

-synthesized inside the neuron for the purpose of neurotransmission

Others are excitatory and increase the likelihood of an action potential by bringing the neuron closer to threshold

Glutamate pt. 2

Facilitates growth and change in neurons and the migration of neurons and migration of neurons in the brain

-Amplifies certain neural signals

-crucial in early development

-amplifies neural transmissions

Direction of neural transmission

Dendrite > Soma > Axon > Synapses

Evolution of the Human Brain

The human brain has been shaped, via natural selection, by the world in which we have lived

Three major regions of the brain

1. hindbrain

2. Midbrain

3. Forebrain

Hindbrain

Oldest brain region

-connected to spinal cord

-regulates breathing, heart rate, arousal, basic Functions for survival

-Includes: Medulla, pons, and cerebellum

Medulla

A hindbrain structure that extends directly from the spinal cord; regulates breathing, heart rate, and blood pressure, and kinds of reflexes like coughing, swallowing, etc

Pons

A hindbrain structure that serves as a bridge between lower brain regions and higher midbrain and forebrain activity

-"bridge"

Cerebellum

A hindbrain structure involved in body movement, balance, coordination, fine tuning motor skills, and cognitive activities such as learning and language

-"Little brain" = contains more neurons than any other single part of the brain

Reflexes

Inborn and involuntary behaviors such as coughing, swallowing, sneezing, or vomiting--that are elicited by specific stimuli

Midbrain

Smallest of the three,

-controls eye muscles, process auditory and visual information, and initiate voluntary movement of the body

-Parkinson's disease has problems here

-Midbrain, medulla, and pons = Brain stem

Reticular formation

A network of nerve fibers that runs up through both the hindbrain and the midbrain; it is crucial to waking up and falling asleep

Forebrain

Last major brain region to evolve and the largest

-includes cerebrum, thalamus, limbic system, etc

-cognitive, sensory, motor function, eating, sleeping, emotions

-Structures are bilateral

Thalamus

Forebrain structure that receives information from the senses and relays it to the cerebral cortex for processing

-receives input from the ears, eyes, skin, or taste buds, and relays sensory information

Limbic System

Includes: hypothalamus, hippocampus, amygdala, cingulate gyrus

Function: emotion and motivation

Hypothalamus

A limbic structure; the master regulator of almost all major drives and motives we have, such as hunger, thirst, temperature, and sexual behavior; also controls the pituitary gland

Hippocampus

A limbic structure that wraps itself around the thalamus; plays a vital role in learning and memory

-most open to change

Amygdala

a small almond-shaped structure located directly in front of the hippocampus; has connections with many important brain regions and important for processing emotional info

-Fear

-determine emotional significance of stimuli

Cingulate gyrus

a belt-like structure in the middle of the brain that plays an important role in attention and cognitive control

Basal Ganglia

A collection of structures surrounding the thalamus involved in voluntary motor control

-affected by Parkinson's disease and Huntington

Cerebrum

each of the large halves of the brain that are covered with convolutions or folds

Cerebral cortex

the thin outer layer of the cerebrum, in which much of human thought, planning, perception, and consciousness takes place

The Four Lobes

-Distinct functions

-bilateral

-Frontal, temporal, parietal, and occipital

-Primary motor cortex

Contralaterality

the fact that one side of the brain controls movement on the opposite side

Cortical localization

Different parts of the cortex are responsible for different functions

Frontal Lobe Functions

-Attention, solve problems, planning, abstract thinking, control of impulses, creativity, social awareness

-More interconnected with other brain regions = insight and creative problem solving

-Youngest and last to develop

The parietal lobes

Makes up the top and rear sections of the brain

-Sensation and perception of touch

Somatosensory cortex

Frontmost portion of the parietal lobes

-lies directly behind the motor cortex (twin regions)

-activated when different parts of the body are touched

-ex: motor cortex moves lips while sensory cortex sense the touch

Temporal Lobes

Lie directly below the frontal and parietal lobes and right behind the ears

Functions: hearing, auditory cortex

Auditory cortex

where sound info arrives from the thalamus for processing

Occipital lobes

Rear of the brain

-The optic nerve travels from the eye to the thalamus to occipital lobes > primary visual cortex = visual info processed

-Individual neurons are specialized for diff. aspects of vision like color

Insula

Small structure inside the cerebrum, active in perception of bodily sensations, emotional states, empathy, and addictive behavior

-communicates with structures of limbic system and involved in decision making

About this deck

By: Noni Wang
Created: 2011-02-19
Size: 59 flashcards
Views: 14

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy