AP Psych Chapter 2

Bio Unit

Psychologists from the biological perspective study what?

the links between our biology and our behavior and mental processes

neuron

a nerve cell that is 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

dendrites

the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body

axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

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

Why is myelin important?

- At birth, babies have not yet myelinated the axons of their neurons. - The development of the myelin sheath, not complete until around age 25, is crucial to behavior, movement and thought. - Deterioration of the myelin sheath can lead to motor impairments, such as multiple sclerosis.

terminal branches

The ends of the axon containing terminal buttons which hold synaptic vesicles that store neurotransmitters

glial cells

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

how is a neural impulse generated?

If the combined received chemical signals exceed a minimum threshold, the neuron fires, transmitting an electrical impulse (the action potential) down its axon by means of a chemistry-to-electricity process

threshold

the level of stimulation required to trigger a neural impulse

what builds up to initiate the action potential?

neurotransmitters received by the dendrites

all-or-none response

neural firing happens at full response or not at all

more stimulation (does/doesn't) produce a more intense neural transmission

doesn't

excitatory signal

Like the gas pedal in a car. Excitatory neurotransmitters signal trigger action.

inhibitory signal

Like the brake pedal in a car. Inhibitory neurotransmitters depress action.

what happens when the excitatory signals exceed the inhibitory signals?

the threshold has been reached and an action potential occurs

resting state of an axon

the outside of an axon's membrane has mostly positively charged sodium (Na+) ions and the interior contains negatively charged proteins and a small amount of positively charged potassium (K+) ions. This creates a slightly negative charge, and the a POLARIZED effect.

what does it mean that the axon membrane is selectively permeable?

the membrane contains voltage gated ion channels that either open up to allow ion exchange (depolarization) or close to prevent ion exchange (polarization)

first step in action potential

The first section of the semipermeable axon opens its gates once the threshold is met. Na+ ions flood in through the channels.

Why do the Na+ ions rush in during action potential?

since the inside of the membrane is slightly more negative, the Na+ ions try to balance the charge, causing a slight depolarization.

second step in action potential

The depolarization changes the electrical charge of the next part of the axon. Gates in this second area now open, allowing even more Na+ ions to flow in.

How do the K+ ions move out during action potential?

gates open in the first half of the axon allowing them to flow out, repolarizing this section of the axon.

third step in action potential

The sodium/potassium pump continues to depolarize new sections of the axon and repolarize the previous sections.

how does the impulse move in action potential?

the influx of positive ions is the neural impulse. the impulse moves down the axon like dominos.

what happens after the action potential moves to the end of the axon?

the refractory period occurs, where subsequent action potentials cannot occur until the axon returns to its resting state

Polarization

the resting state of the neuron, charge is more positive outside the membrane and more negative inside.

depolarization

the action potential; the rushing in and out of positively charged ions

repolarization

the refractory period; the closing of the membrane and reestablishing a more negative charge inside

how do neurons communicate with each other?

the sending neuron releases neurotransmitters across a synapse to the receiving neuron

neurotransmitter

chemical messengers that travel across the synapse and bind to receptor sites on the receiving neuron

synapse

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

how does communication between two neurons work?

when an action potential reaches an axon's terminal branch, it stimulates the release of neurotransmitter molecules. These molecules cross the synaptic gap and bind to receptor sites on the receiving neuron. This will either excite or inhibit a new action potential

reuptake

a neurotransmitter's reabsorption by the sending neuron

Acetylcholine

Neurotransmitter that enables muscle action, learning, and memory. If malfunctioned, it can produce alzheimer's disease

Dopamine

neurotransmitter that influences movement, learning, attention, and emotion. oversupply linked to schizophrenia, undersupply liked to tremors and decreased mobility in Parkinson's disease

serotonin

A neurotransmitter that affects hunger,sleep, arousal, and mood. undersupply linked to depression

norepinephrine

neurotransmitter that helps control alertness and arousal. undersupply can depress mood

GABA

a major inhibitory neurotransmitter. undersupply linked to seizures, tremors, and insomnia

glutamate

A major excitatory neurotransmitter; involved in memory. oversupply can overstimulate the brain, producing migraines or seizures

endorphins

Neurotransmitters that influence the perception of pain or pleasure. oversupply with opiate drugs can suppress the body's natural endorphin supply

Neurotransmitters have different...

pathways

Agonist

a drug molecule that increases a neurotransmitter's action

antagonist

a drug molecule that inhibits or blocks a neurotransmitter's action. it may block reuptake

Humans are what type of system?

Biopsychological

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

nerves

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

types of neurons

sensory, motor, interneurons

sensory neurons

carry information from the sense receptors to the CNS

motor neurons

carry information from the CNS to muscles and glands

How is the nervous system divided?

Look at picture!

Central Nervous system

Brain and Spinal Cord; the body's decision maker responsible for coordinating incoming sensory messages and outgoing motor messages

Peripheral Nervous system

Motor and Sensory Neurons; Connects the body to the CNS by gathering information from the senses and transmitting messages from the CNS

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system

the division of the peripheral nervous system that controls glands and muscles of internal organs

Sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

brain

Comprised of the cortex and subcortical structures carrying out various functions, as well as Nerves arranged into neural networks

Spinal Cord

2-Way connection between the PNS and brain that oversees the sensory and motor pathways of reflexes

How does a reflex occur?

1 Sense receptors in the skin send signals up through the spinal cord via sensory neurons. 2 Interneurons in the spinal cord receive the information from the sensory neurons and send signals back through motor neurons. 3 Motor neurons connect to muscles in the body and direct movement.

Endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

differences between the nervous and endocrine systems

neurons releasing neurotransmitters v. glands releasing hormones, neurotransmitters moving across synapses v. hormones moving through the bloodstream, neural transmission is fast v. hormonal secretion is slow.

Adrenal Glands

a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.

norepinephrine is both a...

neurotransmitter and hormone

epinephrine v. norepinephrine

epinephrine arouses the body, norepinephrine calms it

pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Growth Hormone

regulates growth and metabolism

Oxytocin

stimulates the uterine contractions of childbirth and milk secretion during breast feeding; also promotes trust

lesion

brain tissue is destroyed and researchers study the impact on functioning

stimulation

brain regions are stimulated electrically, chemically, or magnetically and researchers study the impact on functioning

EEG

recording of the waves of electrical activity that sweep across the brain's surface measured by electrodes placed on the scalp

MEG

a brain imaging technique that measures magnetic fields from the brain's natural electrical activity

CAT

x-ray photographs taken from different angles and combined by computer to show a slice of the brain's structure; shows structural damage

PET

a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task; shows activity

MRI

a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain

fMRI

A measure of blood flow and brain activity by comparing successive MRI scans to show brain function or as well as structure. Shows damage.

What imaging techniques show structure of the brain?

CAT, MRI, fMRI

What imaging techniques show brain functioning?

EEG, MEG, PET, fMRI

Medulla

the base of the brainstem; controls heartbeat and breathing

pons

lays just above the medulla and controls sleep and helps coordinate movements

reticular formation

a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal and filtering incoming sensory stimuli

Thalamus

At the top of the brainstem, the relay station for incoming and outgoing sensory information (with the exception of smell)

Cerebellum

At the rear of the brainstem, (the "little brain") helps with processing sensory input, coordinating movement and balance, and nonverbal movement and memory

What makes up the limbic system?

hippocampus, amygdala, hypothalamus

amygdala

two lima bean-sized neural clusters in the limbic system; linked to emotion, fear, and aggression.

hypothalamus

below the thalamus, directs eating drinking and body temperature, helps govern the endocrine system via the pituitary gland, linked to emotion and reward

hippocampus

small structure with two "arms" that wrap around the thalamus that helps process for storage explicit (conscious) memories of facts and events

what does the limbic system control?

emotions, memory, drives

cerebral cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.

four lobes that make up the cerebral cortex

frontal, parietal, temporal, occipital

frontal lobes

the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments

parietal lobes

portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position

temporal lobes

portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving auditory information primarily from the opposite ear

occipital lobes

portion of the cerebral cortex lying at the back of the head; recieves visual information, primarily from opposite visual field

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

area at the front of the parietal lobes that registers and processes body touch and movement sensations

auditory cortex

the area of the temporal lobe responsible for processing sound information/receiving information from the ears

visual cortex

the area of the occipital lobe that recieves information from the eyes

damage to which area could interfere with the ability to plan for the future?

frontal lobes

association areas

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