U3: Biological Bases: The Brain and Nervous System Flashcards
EEG
measures changes in brain electrical activity through electrodes placed on the head
CAT scans
generate cross-sectional images of the brain using X-ray pictures taken from different angles
MRI
use of powerful electromagnets and radio waves to get 3D structural image of brain
Functional MRI (fMRI)
allow scientists to view brain as it is working
PET scan
diffusion of radioactive glucose in the brain, allows observation of what brain areas are at work
nervous sytem
divided into two: central nervous system (CNS) and peripheral nervous system (PNS)
central nervous system (CNS)
brain and spinal cord
peripheral nervous system (PNS)
all other nerves in the body except brain and spinal cord
- subdivided into somatic nervous system and autonomic nervous system
neurons
- nerve cells
- form a network that extends to the spinal cord
- nerves = interconnected neurons
- nerves of spine are responsible for conveying information to and from the brain and the PNS
afferent neurons
- sensory neurons
- nerves that send information to the brain
- “afferent connections arrive to the brain”
efferent neurons
- motor neurons
- nerves that convey information from the brain
- “efferent neurons are exiting the brain”
reflexes
- quick and involuntary responses to environmental stimuli
- movement where control is by direct transmission from afferent to efferent cells at the spinal cord, not involving the brain
- path of reflex arc: from sensory neurons to motor neurons
somatic nervous system
- part of PNS
- responsible for voluntary movement of large skeletal muscles
autonomic nervous system
- part of PNS
- controls nonskeletal or smooth muscles (like heart or digestive tract); these muscles aren’t usually under voluntary control
- can be further divided into sympathetic and parasympathetic nervous systems
sympathetic nervous system
- associated with processes that burn energy
- responsible for heightened state of physiological arousal/flight or fight response
- increase in heart rate and respiration, decrease in digestion and salivation
parasympathetic nervous system
- responsible for conserving energy
- helps in calming down: lowers heart rate, sends blood to stomach for digestion, returns body to homeostasis
hindbrain
- oldest part of the bran to develop in evolutionary terms
- composed of cerebellum, medulla oblongata, reticular activating system, and pons
cerebellum
- in hindbrain
- controls muscle tone and balance
medulla oblongata
- in hindbrain
- control involuntary actions/basic life functions (i.e. digestion, breathing, heart rate)
reticular formation (RAS)
- in hindbrain
- controls arousal (wakefulness and alertness)
pons
- in hindbrain
- bridge between regions of the brain, passes neural information from one region to another
midbrain
tectum and tegmentum
tectum and tegmentum
- in midbrain
- tectum = roof of brain, tegmentum = floor of brain
- govern visual and auditory reflexes
forebrain
made up of limbic system and cerebral cortex
limbic system
- composed of thalamus, amygdala, hippocampus, and hypothalamus
- the emotional center of the brain
thalamus
- in limbic system, forebrain
- relays sensory information; receives and directs sensory information from visual and auditory systems
hippocampus
- in limbic system, forebrain
- involved in processing and integrating memories
amygdala
- in limbic system, forebrain
- implicated in the expression of anger and frustration
hypothalamus
- in limbic system, forebrain
- controls temperature, water balance, hunger, and sex drives
- orchestrates activation of sympathetic nervous system and endocrine system
- lateral hypothalamus: “on switch” for eating
- ventromedial hypothalamus: “off switch” for eating
cerebral cortex
- part of the forebrain
- wrinkled outer later of the brain
- involved in higher cognitive functions like thinking, planning, language use, and fine motor control
- receives sensory input (sensory cortex) and sends out motor information (motor cortex)
- covers two sides of brain: left and right cerebral hemispheres
- can be divided into four lobes: frontal, parietal, temporal and occipital
corpus callosum
- in forebrain
- a band of connective nerve fibers that join the right and left hemispheres
left hemisphere
typically specialized for language processing
- broca’s area: expressive aphasia = loss of ability to speak
- wernicke’s area: receptive aphasia - inability to comprehend speech
right hemisphere
process certain kinds of visual and spatial information
roger sperry
demonstrated that the two hemispheres can operate independently of each other, proved this with experiments of split brain patients
- contralateral processing
contralateral processing
- right visual field is processed on the left, more verbal side of the brain
- left visual field is processed on the right, more visual side of the brain
association areas
areas of cerebral cortex
- responsible for associating information in the sensory and motor cortices
- damage to this area can lead to apraxia (inability to organize movement), agnosia (difficulty processing sensory input), alexia (inability to read), and agraphia (inability to write)
frontal lobe
responsible for higher level thought and reasoning, including working memory, paying attention solving problems, making plans, forming judgments, and performing movements
parietal lobe
handles somatosensory information, home of primary somatosensory cortex, receives information about temperature, pressure, texture, and pain
temporal lobe
handle auditory input and is critical for processing speech and appreciating music
occipital lobe
processes visual input
soma
nucleated cell body of a neuron
dendrites
branching out from the soma, they receive input from other neurons through receptors on their surface
axon
long, tube-like structure that responds to input from the dendrites and soma, it transmits a neural message down its length and passes its info to other cells
myelin sheath
fatty coat surrounding the axon, they serve as insulation for the electrical impulses carried down the axon and also speed up the rate at which electrical information travels down the axon
- the better insulate, the fast and more efficient the sending of action potentials
nodes of Ranvier
the small gaps between the myelin, they help seep up neural transmission
terminal buttons
- knobs on the branched end of the axon
- they come very close to the cell body and dendrites of other neurons but they don’t touch
- they send neurotransmitters
synapse
- the gap between the terminal buttons of one neuron and dendrites of another
- terminal buttons send neurotransmitters across the synapse where they bind with receptors on subsequent dendrites
neurotransmitter
- chemical messenger
- communication between cells happens via neurotransmitters, which bind to receptors on the dendrites of the adjacent neurons
resting membrane potential
- electric potential across the plasma membrane of approx. -70 millivolts
- interior of the cell is negatively charged compared to positively charged exterior
action potential/nerve impulse
- a disturbance in the resting membrane potential
- is the depolarization of the plasma membrane that travels along an axon
- depolarization: a change in the membrane potential from the resting membrane potential to a less negative, or even positive, potential
- movement of ions into and out of neuron through ion channels, leading to eventual release of neurotransmitter
- repolarization returns the membrane potential to normal
- all or none; are generated or not
absolute refractory phase
- after neuron is fired
- period where no amount of stimulation can cause the neuron to fire again
relative refractory phrase
- after absolute refractory phrase
- when neuron needs much more stimulation than usual to fire again
excitatory neurotransmitters
excite the cell or cause the neuron to fire
inhibitory neurotransmitters
inhibit or stop the cell from firing
reuptake
process where neurotransmitter that is released is absorbed back into the cell, instead of it conducting the impulse to the next cell
acetylcholine
affects memory function, as well as muscle contraction, particularly in the heart
serotonin
related to arousal, sleep, pain sensitivity, and mood and hunger regulation
dopamine
associated with movement, attention, and reward
- imbalances may play a role in parkinson’s disease and in schizophrenia
GABA
inhibitory neurotransmiter
glutamate
excitatory neurotransmitter and the all-purpose counterpart to GABA
norepinephrine
affects levels of alertness
- lack of it is implicated in depression
endorphins
the body’s natural pain killers
endocrine system
- another way which various parts of our bodies relay information to one another
- works through glands, which release hormones
hormones
- affect cell growth and proliferation
- affect body for long periods of time
- coordinate with a wide range of responses
- present in the bloodstream
pituitary gland
- primary gland of endocrine system
- aka master gland
- releases hormones that control hormonal release by other glands
- located under hypothalamus (which controls it)
