Ch. 3: Biological Processes Flashcards
neurons
- individual cells that receive, transmit, & integrate info. w/in nervous system
- main components of the nervous system
- communication by neurons is electrochemical
sensory neurons
carry info from environment toward spinal column & brain
interneurons
transfer info from one neuron to another
motor neurons
send messages & commands away from brain & spinal column to muscles & glands that produce responses
dendrites
fibers that extend outward from a neuron & receive info from other neurons
soma
cell body of a neuron
axon
long-tail like part of neuron that serves as cell’s transmitter
terminal buttons
tiny swellings at end of axon that contain chemicals important to neural transmission
myelin sheath
insulation wrapped around axon that protects it & speeds up transmission of info; made up of glial cells, which perform variety of functions
describe path info takes through neuron
1) dendrites receive info from other neurons
2) soma holds all received messages summed
3) if determined in axon hillock, an action potential travels along axon to the…
4) axon terminal buttons releases chemicals (neurotransmitters) into synapse
5) dendrites from another neuron receive neurotransmitter & process may repeat
reflex
an automatic reaction processed in spinal chord, not the brain, which allows a quick, simple, direct response to an environmental event
- e.g. pulling hand away from flame
sensory neurons–> interneurons –> spinal chord –> motor neurons
action potential
- all-or-nothing electrical signal that travels down neuron’s axon
- based on all messages received, either excitatory or inhibitory, in cell body of neuron
- if sum of signal (in axon hillock) is excitatory, neuron fires own signal for transmission to next neuron
- if sum is inhibitory, no message is transmitted
synapse
small gap between cells, typically btw terminal buttons of one neuron & dendrites or cell body of another
agonists
drugs that can increase or mimic action of naturally occurring neurotransmitters
- e.g. nicotine mimics acetylcholine, stimulant effect
antagonists
drugs that can block the action of neurotransmitter
- e.g. curare acetylcholine receptors, can stop muscle movement, including breathing
central nervous system (CNS)
the brain & the spinal chord; the central executive–receives info, makes decisions
peripheral nervous system
nerves outside the brain & spinal chord
somatic systems
nerves that 1) transmit sensory info to brain & 2) connect to skeletal muscles to initiate movement
autonomic system
regulates heart rate, digestion, blood pressure, activities of internal glands
sympathetic division
(arousing)
- sets in motion the “fight or flight” response when we are faced w/ an emergency
- chemicals released which increase heart rate, blood pressure, breathing rate (& other changes) to help respond to threat
parasympathetic division
(calming)
calms body down, restores body functions to normal levels, helps replenish stored energy levels after emergency has passed
electroencephalogram (EEG)
monitors gross electrical activity in brain by attaching recording electrodes to scalp
used for research & diagnosing psychological & sleep disorders, epilepsy
computerized tomography scan (CT scan)
- provides a 3D picture of brain, including abnormalities in brain tissue
- X-rays are passed through body & analyzed by computer
- detect tumors, injuries, physical bases for psychological disorders
positron emmission tomography (PET scan)
measures how an ingested radioactive substance is absorbed in different parts of brain while specific tasks are being performed
magnetic resonance imaging (MRI)
produces extremely detailed 3D images of changes in blood flow or oxygen use as patient thinks or behaves
hindbrain
- most “primitive” part
- sits just above top of spinal chord
- basic life support
- oldest of evolutionary terms
- damage here, including effects of drugs, can be lethal
medulla & pons
- associated w/ heart rate, breathing, blood pressure, reflexes
- act as pathways for neural signals traveling btw brain & spinal chord
reticular formation
controls general arousal, sleep, & consciousness
cerebellum
(“little brain”)
involved in complex movements & motor memory
midbrain
- sits on top of hindbrain
- receives info from many sources, including the sense organs
tectum
- made up of superior & inferior colliculus
- relay station for visual & auditory signals, coordinates movement in response to sensory events
substantia nigra
- part of basal ganglia
- active in release of dopamine, neurotransmitter related to movement & coordination, learning, drug addiction, & emotion
- degeneration of substantia nigra & resultant decreased levels of dopamine in brain are thought to be cause of Parkinson’s disease
forebrain
outer portion of brain, including thalamus, hypothalamus, limbic system, cerebral cortex, & corpus collosum
thalamus
- just above midbrain
- main processing point for sensory info being sent to cerebral cortex
hypothalamus
- just below thalamus
- regulates eating, drinking, body temp, sexual behavior, & release of hormones from pituitary gland
limbic system
made of several structures, including amygdala & hippocampus
amygdala
motivational & emotional behaviors
-e.g. fear, aggression, defensive actions, & ability to recognize emotions in others
hippocampus
active in formation of memories, esp. for specific personal events
cerebral cortex
- 80% od human brain’s volume
- seat of our higher mental processes
- divided into 2 hemispheres: left controls sensory & motor functions on the right side of body & vice-versa
- each hemisphere divided into 4 lobes
corpus collosum
connects 2 hemispheres of cerebral cortex
frontal lobes
- executive/higher order functions– planning & organizing voluntary behavior & decision making; problem solving, certain remembering, socialization, inhibitions, personality
- contains motor cortex
motor cortex
- lies at rear of frontal lobe
- controls voluntary muscle movements, including those involved in language production (Broca’s area in left hemisphere)
- topographic organization
- mirror neurons located here
topographic organization
(mapping)
adjacent parts of the body are activated by adjacent groups of neurons in motor cortex
mirror neurons
- found in motor cortex
- involved in empathy & ability to take perspectives of others
parietal lobes
contains Somatosensory cortex
somatosensory cortex
- located in parietal lobe
- primarily involved processing of sensory info related to temp & touch, including pressure & pain
temporal lobes
- on either side of cortex
- involved in processing auditory info received by ears
- left temporal lobe includes Wernicke’s area
Wernicke’s area
- located in left temporal lobe
- where spoken language comprehension occurs
occipital lobes
- at back of brain
- visual processing: receiving info from receptor cells in eyes, integrating color, motion, form
- hemispheric processing: images originating in right visual field are processed in left hemisphere’s occipital lobe & vice-versa
left hemisphere
- verbal tasks, reading, writing
- problem solving, explanations
- body’s right side sensory input and motor output
endocrine system
- initiate & control growth & provide long-term regulation of internal biological systems
- uses hormones, not neurons, released from various glands into bloodstream as way to communicate
- nervous system & endocrine systems connected
- —hypothalamus controls Pituitary gland which regulates activity of other glands
- —released hormones can affect firing rates of neurons
- —fight or flight (uses both endocrine & autonomic nervous systems)
neuroplasticity
- brain’s ability to reorganize itself by forming new neural connections throughout life
- allows neurons in brain to compensate for injury & disease & to adjust their activities in response to new situations/changes in their environment
