AP Psych Unit 2

chronological order of how a message gets sent (neurons)

1. Dendrites (recieves msg from other cells)

2. Soma (cell body)

3. Axon (passes msgs away from the cell body to other neurons, muscles, or glands)

4. Terminal branches of neuron (form junctions w other cells)

what is the myelin sheath

a layer of fatty cells segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses

if it deteriorates you get MS

things to know about axons

axon

• transmits electrical impulses away from the cell body to other neurons, muscles, or glands.

• generally one axon per cell

• no ribosomes

• myelin sheath

• branch further/longer from cell body

things to know about dendrites

• bring info to the body

• many per cell

• ribosomes

• no myelin sheath

• branch near the cell body

types of neurons?

1. Sensory

2. Interneurons (found exclusively within spinal cord & brain) → stimulated by signals reaching them from sensory neurons, other interneurons, or both

3. Motor Neurons (transmit impulses— send msgs from CNS to muscles, glands)

what are glial cells

holds neurons together, supports them, protects them, removes waste, allows them to work more efficiently. There are more glial cells than neurons.

main difference between sensory & motor neurons?

• sensory → afferent → carry incoming info from sense receptors to the CNS

• motor → efferent → carry outgoing info from the CNS to muscles & glands

• interneurons connect the two neurons

what is action potential

a brief electrical charge that travels down an axon and is generated by the movement of positively charged atoms (Na & K) in and out of channels in the axon’s membrane

what is a reflex

• simplest form of neural transmission

• afferent (s) & efferent (m) nerve fibers fire msgs via interneurons to the spinal chord

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(ex— hand touches candle flame)

• Sensory (Afferent) Neurons in your skin detect the extreme heat and fire an action potential.

• They carry this electrical signal straight to your spinal cord.

• Inside the spinal cord, a short neuron called an Interneuron acts like a processing shortcut. It immediately triggers a response.

• Motor (Efferent) Neurons instantly receive the signal from the interneuron and command your biceps to contract, pulling your hand away.

while hand jerks immediately, don’t fully “feel” the pain until later

Continues traveling up the spinal cord, through the brainstem, and into the thalamus (your brain's sensory relay station). From the thalamus, the signal is directed to the somatosensory cortex in your parietal lobe.

acetylcholine (ACh)

• enables muscle action, learning, and memory

• malfunctions— ex: ACh producing neurons deteriorate w Alzheimers

dopamine (the chase)

• influences movement, learning, attention, and emotion

• excess dopamine receptor activity → linked to schizo

• starved of dopamine → tremors + decreased mobility of parkinson’s

serotonin (catch)

• affects mood, hunger, sleep, arousal

• undersupply = depression

• prozac and other antidepressant drugs raises serotonin levels

norepinephrine

• helps control alertness + arousal

• undersupply can depress mood

GABA

• major inhibitory neurotransmitter (decreases likelihood of action potential)

• undersupply linked to seizures, tremors, and insomnia

glutamate

• major excitatory neurotransmitter, involved in memory

• oversupply can overstimulate brain, producing migraines or seizures (why some people avoid MSG)

how do drugs/toxins work (4)

• some reduce the amt. of neurotransmitters in the synaptic gap

• some speed up (excite) the release of transmitter chemicals into the synaptic space

• some work directly on receptor sites

  • ex: LSD → inhibits serotonin => dream like state

• some block receptors

  • curare => blocks Ach receptors, produces paralysis

agonist vs antagonist

agonist

• mimics or enhances the effects of a neurotransmitter

• binds to and activates receptor sites on a post-synaptic neuron, encouraging neural firing. It can also work by blocking re-uptake

• ex: LSD, SSRI

antagonist

• blocks or inhibits the effects of a neurotransmitter

• binds to receptor sites, but does not activate them. Just occupies the space to prevent the real neurotransmitter from binding & reduce neural firing.

• ex: curare

what is a complex neural network

Interconnected neurons form networks in the brain. These networks are complex and modify with growth and experience.

what is plasticity

the brain’s ability to modify itself after some type of injury or illness

brainstem

• begins where the spinal cord swells and enters the skull

• responsible for automatic survival functions

• (contains midbrain, pons, & medulla)

thalamus

• brain’s sensory switchboard, located on top of the brainstem

• directs messages to the sensory areas (except for smell) in the cortex & transmits replies to the cerebellum and medulla

cerebellum

the “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements & balance

the limbic system

• doughnut shaped system of neural structures at the border of the brainstem and cerebrum

• associated w fear, aggression, and drives for food and sex

• includes hippocampus, amygdala, and hypothalamus

medulla

base of the brainstem that controls heartbeat + breathing

reticular formation

nerve network in the brainstem that plays an important role in controlling arousal

amygdala

two almond shaped neural clusters linked to fear, anger, aggression

hypothalamus

below thalamus

• eating, drinking, body temp, control of emotions (mantainance activities)

• helps govern endocrine system via pituitary gland

spinal cord

complex cable of neurons that run down the spine, connecting the brain to most of the rest of the body. Made up of bundles of long nerve fibers

functions (2)

1. permits reflex movements

2. carry msgs to and from brain

cerebral cortex

• fabric of interconnected neural cells that covers the cerebral hemispheres

• ultimate control & info processing center

4 lobes (each brain hemisphere is divided into) + functions

• frontal: judging, planning, problem solving, etc.

• temporal: listening & comprehension

• occipital: field of vision + visual processing

• parietal: integrates sensory info

motor vs sensory cortex

• motor: area at the rear of the frontal lobes that controls voluntary movements

• sensory: recieves info from skin surface & sense organs

broca’s vs wernicke’s area

broca

• located in the frontal lobe, directs muscle movement in speech

• language motor area → manages movements to produce spoken language

wernicke

• located in left temporal lobe

• language comprehension

aphasia

impairment of language due to damage of Broca’s or Wernicke’s area

(expressive— broca. sensory— wernicke)

brain lesion + ex

destroys brain tissue to study animal/human behavior after such destruction

• ex: cutting the corpus callosum in half. seizures on the left side stay localized, can’t cross the bridge

• become ‘split brain patients’

tools for studying the brain (5)

• clinical observation

• EEG

• PET Scan

• MRI

• CT Scan

clinical obsv

• observe effects of specific brain diseases/injuries (but person has to be dead)

EEG

• measures electrical activity in brain (jagged graph)

PET Scan

• position emission topography

• detects radioactive form of glucose while the brain performs a task (red = hot spots)

MRI

• magnetic resonance imaging

• produces comp generated images that distinguish among diff types of brain tissue

• top images → ventricular enlargement in schizo patient

fMRI (functioning MRI) → unlike regular MRI, it shows structural detail and active areas

CT Scan

• takes series of X-Ray images and uses computer processing to create cross sectional images of bony structures + tissue. More detail than X-Rays

• good for detecting things like tumors

‘AP Psych Master Formula for Split Brains’

• Right Visual Field → Left Hemisphere → Can SAY it.

• Left Visual Field → Right Hemisphere → Can DRAW POINT to it with the Left Hand (but cannot say it).

nervous system parts (2)

• nervous system: consisting of all the nerve cells, it’s the body’s speedy communication sys

• divided into

  • CNS (central) → consists of brain & spinal cord

  • PNS (peripheral)

PNS

• sensory & motor neurons that connect CNS & rest of body

• body’s input/output machine. Sends & receives info throughout the entire body

endocrine system parts to know

• hypothalamus → controls pituitary gland (base of brain), bridge between nervous & hormone systems

• thyroid → metabolism, in neck

• pituitary → right under hypothalamus, growth hormones. secrets other hormones that affects other glands

• adrenal → fight or flight