Biology and Neuroscience Flashcards
Breakdown of the nervous system
CENTRAL NS
Brain
- Forebrain, midbrain, hindbrain
Spinal cord
PERIPHERAL NS
Autonomic
- Sympathetic, parasympathetic
Somatic
Somatic NS
Intentional reactions/responses
Autonomic NS
Automatic reactions/responses
Sympathetic NS
- A.k.a flight, freeze/fight
- Activated when danger is sensed by amygdala to increase chances of survival
- Digestive processes temporarily slow down to focus on survival
Parasympathetic NS
- A.k.a rest and digest
- Relaxed
- Eliminates/stores waste and delivers nutrients
Acute stress
Stress from immediate threat that eventually goes away
Chronic stress
Long-term, hyperactive stress = burn out after a long time
Limbic system
Controls when we’re in fight/flight based on habit, instincts and primitive reactions
- Takes over for front lobe (where rational decisions are made) after it’s deactivated
4 main lobes
Frontal (motor behaviour & reasoning)
Parietal, occipital, temporal (perceive world and make conclusions)
Cerebral cortex
Where higher lvl of perception of the world occurs and origin of all controlled interactions w/ external world
Midbrain
Primitive and focuses more on survival by controlling automatic processes and stores memories
Lateralization
Brain is made of separate hemispheres
Occipital lobe
Lower part of lobe used for vision
Scotoma
Blind spot in someone’s vision b/c of damage to primary visual cortex
Visual association cortex
Connects visual input w/ memory, allowing categorization and perception of visual images
Agnosia
Inability to name a common object upon seeing it
Temporal lobe
Where auditory processes happen
- Primary auditory cortex (inside upper temporal lobe)
- Auditory association cortex (lateral surface of temporal lobe)
Parietal lobe
- Primary somatosensory cortex: Perception of body (motor strip)
- Parietal association cortex: Complex spatial functions that different across hemispheres (sensory strip)
Proprioception
Spatial location of body parts
Left side neglect
When people neglect left side of space as if it’s not there
Cerebellum
Fibres at back bottom of brain that works w/ parietal lobe & is important to motor movement
Premotor cortex
Controls complex movement & combines signals from primary motor cortex
Contributes to decision making
Proportional representation
Amount of break devoted to specific part of body depends on its relevance
Affect (ah-fect)
Emotional state
Confabulate
Inability to deceive well/at all
Neurons
Cells that transmit electrical impulses to and from the brain to form thoughts and actions (communicators)
Glial cells
Helper cells that assist neurons w/ communication and providing structural support
Dendrites
Extensions of cell body (soma) that communicate w/ other neurons
Nucleus of neuron
- Membrane bound and found in soma
- Includes nucleolus and chromosomes needed to produce proteins in cell
Axon hillock
Intersection b/w soma and axon
Axon
Part of neuron membrane that delivers messages
Axon terminal
Releases neurotransmitter when action potential reaches it
Neurotransmitter
Chemicals released from end of an exon and acts as messages to other neurons and body parts and typically binds to receptors
Receptors
Proteins embedded in cell body membrane & are built to receive messages from neurotransmitters
Soma
Cell body of neuron containing organelles and control metabolic processing
Terminal button
Very edge of axon terminal wher eneurotransmitter exits
Vesicles
Bubbles in terminal button that store neurotransmitters and open up to send neurotransmitters to next neuron’s dendrites
Presynaptic neuron/axon terminal
Releases neurotransmitter into synapse
Synaptic cleft
Space b/w end of neuron that releases neurotransmitter and end that receives
Synapse
Small fluid-filled gap b/w neurons into which neurotransmitters are released
Postsynaptic receptors
Neurons that contain receptors ready to bind to neurotransmitter fr presynaptic neuron (usually on dendrites)
How fast does communication b/w neurons happen?
About 5 milisecs
Myelin
Protein and fatty substance that wraps around axon to protect and increase speed of action potentials/electrical impulses
Nodes of Ranvier
Gaps in myelin that lets ions enter into axon and change charge inside
Ions
Particles w/ positive/negative charges and their movement = electricity
Ions involved in action potential
Sodium, chloride and potassium
Polarized
- Cell is at rest and won’t release neurotransmitters
- Large # of negatively charged ions (about -70 millivolts)
Depolarized
- When cell moves away from being polarized
- Becomes more positive
- More likely to activate and send neurotransmitter the more depolarized
Channels
Openings that allow ions to either enter/leave cell
Propagation
Process by which electrical impulses get sent to end of neuron
Threshold
AMmount of voltage change required to trigger open voltage-gated channels
Explain the 5 steps of the movement of action potential
1) Threshold
- Nerve impulse opens gate and Na+ enters cell
2) Depolarization
- Voltage-gated channels are opened, which increases positive ions in cell
- Cell is relatively less negative/polarized compared to outside = depolarized cell
- Occurs in Noes of Ranvier
3) Repolarization
- Na+ channels close = K+ channels open
- Amount of positive ions decreases and inside becomes relatively negative compared to surrounding fluid
4) Refractory period
- K+ channels open long enough to cause neurons to become “extra” negative compared to outside = hyperpolarized cell & temporarily increases difficulty of reaching threshold again
5) Resting state
- Neuron stabilizes and returns to resting state potential (about -70 mV)
Excitatory
Neurotransmitters that make neuron move closer to activation (e.g. glutamate, acetylcholine, dopamine, serotonin, norepinephrine, endorphins)
Inhibitory
Neurotransmitters that make neuron move away from activation and causes hyperpolarization (e.g. GABA, dopamine, serotonin, norepinephrine, endorphins)
Agonist
Chem from outside body that can mimic/enhance actions of neurotransmitters
Endogenous
Substance naturally produced in nervous system
Antagonists
Chem from outside body to shut off receptor
Competitive
Agonists/antagonists that will compete w/ neurotransmitter for binding side (direct)
Non-competitive
Agonists/antagonists that bind at a different site and interfere w/ receptor function (indirect)
Partial agonists/antagonists
Chem from outside body that either partially enhances/mimics/blocks neurotransmitter action
Ratio of glial cells to neurons
10:1
Glial cell functions
- Structural support for neurons
- Bring nutrients
- Remove waste and dead neurons
- Speed up electrical impulses
Oligodendrocytes
Glial cell that wrap myelin insulation around axons in CNS
Schwann cells
Glial cells that wrap myelin insulation around axons in PNS
Astrocytes
Glial cells that help get nutrition to neurons and maintain balance of ions in/out neurons
Neural networks
Neurons organized in an interconnected group, dedicated to a set of functions
Nerve
Large bundle of axons from many neurons
Efferent vs afferent
- Efferent: Carries signals away fr. CNS
- Afferent: Carries signals to CNS
Neuroplasticity
ABility of neurons and networks to change
Neocortex
Outerpart of brain responsible for high-lvl processing of info (conscious thought/decision-making)
Medulla
Part of brain closest to spinal cord that helps regulate life functions
Gray matter
- Neurons and glia
- Local processing of info
White matter
- Bundles of myelinated axons
- Helps share info by connecting neurons via axons and dendrites
Somatic
Part of PNS that controls voluntary movement and communicates w/ skeletal muscles (torso, head, limbs)
Autonomic
Part of PNS that controls automatic bodily functions
Vertebrae
Individual joints that make up vertebral column and provides spine with ability to flex, extend and twist
Parasympathetic NS
- Body is in relaxed state to rest, recover and repair
- Originates in lower brain and socral spinal cord
Sympathetic NS
- Controls action that require excitement
- Mostly neurons and supporting cells in spinal cord
- Deactivates parasympathetic
- Focusses on survival
Frontal lobe
- Anterior = decision making
- Posterior = movement
- Prefrontal cortex gets input from across cerebral cortex to help decide why and how we do things
Temporal lobe
- Forming memories
- Processing sound (includes primary auditory cortex)
Pons
- Connects info to/from brain
- Regulate arousal, coordinates senses w/ cerebellum and controls facial expression and eye movement
Medulla oblongata
- Closest part to spinal cord
- Regulates life functions (e.g. breathing, heart rate)
Cerebellum
- A.k.a “little brain”
- 2 lobes
- Helps w/ movement and problem-solving
Spinocerebellar
Part of cerebellum that controls motor patterns
Vestibulocerebellar
Part of cerebellum that controls posture and balance
Cerebrocerebellarr
Part of cerebellum that controls timing and planning movements
Alternative names for forebrain, midbrain, and hindbrain
Prosencephalon, mesencephalon, rhombencephalon
Occipital lobe
- Visual cortex processes visual info and light
Parietal lobe
- Association lobe = integrates sensory info from across brain
- Includes primary sensory processing area for touch
- Includes visual info from visual cortex
- Helps orient ourselves in environment
Somatosensory cortex/postcentral gyrus
Primary region for processing touch
Motor cortex/precentral gyrus
Neurons that initiate voluntary movement
Vestibulocochlear nerve
Originates in inner ear and helps brain sense its orientation and regulations L-R coordination
Reticular Activating System (RAS)
Network of cells in pons and medulla to help regulate level of awareness and alertness
- Filters out irrelevant stimuli and brings important ones to the rest of the brain
Nuclei/ganglia
Netwrok of neurons/glia grouped together to perform certain functions
Prefrontal cortex
Front part o frontal lobe involved in decision-making
Limbic system
Nuclei/ganglia that regulates emotions, helps regulate endocrine activity, and form emotional memories
- Integrates primitive functions w/ high-order thought
Amygdala
- Network that becomes more active when we learn fear response
- Increases secretion of adrenaline/norepinephrine in fight or flight
- Forms memories associated w/ strong emotions
- Analyzes emotional value and intensity of a stimulus
- Connects w/ hippocampus and thalamus for formation of emotional memories and coordinate behaviour
Amygdalectomy
Experimental destruction of amygdala in animals, making them docile/less reactive to threats
Hippocampus
Acts as a gateway to forming new memories
- Located in temporal lobe
- Essential for memory creation and imagination of new possibilities
Steps to forming memories
1) Sensory data is transcribed by neurons in cortex and travels to hippocampus
2) In hippocampus, proteins strengthen cortical synaptic connections
3) If stimulus was strong enough/recalled fora few days after, memory gets transferred back to cortex for long-term storage
Cingulate gyrus
Activates when we experience unpleasant things
Hypothalamus
Controls some functions in autonomic and endocrine systems
- Secretes hormone that controls pituitary gland
Basal ganglia
Interconnected groups near base that help w/ learning movement and coordinating movement patterns
Direct path vs indirect path in basal ganglia
- Direct path = dopamine excites neuron = movement occurs
- Indirect path = dopamine inhibits neuron = movement prevented
Dorsal striatum
- Closer to neocortex and coordinates movement
- Includes caudate nucleus and putamen
Ventral striatum
- Closer to neocortex and coordinates movement
- Globus pallidus: Paleglobe whose role is inhibiting circuits in thalamus to control how sensory info is coordinated w/ movement
- Substantia nigra: Dark substance; Sends inhibitory signals to thalamus to coordinate sensory w/ motor plans
Auditory cortex
Auditory info
Visual cortex
Match visual info w/ other senses’ perception
Association cortex
Integrate infro from multiple areas
Somatosensory cortex
Feeling/touch
Motor cortex
Movement commands
Neocortex
Part of brain that integrates and makes sense of all sensory info and is associated w/ higher order functions
Ventromedial prefrontal cortex
Modulate behaviour based on fear
Dorsolateral prefrontal cortex
Maintain info in working memory and change actions based on task
Wernicke’s area
Posterior temporal lobe necessary for processingand understanding language
Corpus callosum/”tough body”
Thick bundle of fibers that connects hemispheres and allows them to share info
- All sensory info crosses here except olfactory
Pituitary gland
- Controls adrenal gland
- Releases many hormones that affect sexual behaviour, reproduction, circulatory function, hunger and responses to aggression
Pineal gland
Secretes melatonin and regulates sleep cycles
Hypothalamic-pituitary-adrenal axis
Connects brain and endocrine system to cause cycle of chronic stress
Staining method
Using dye to make nerves visible under a microscope (1800s)
“Patch-clamp” technique
Record electrical activity of individual neuron (1900s)
Electroencephalogram (EEG)
Record directly from clusters of electrical activity in the brain (1924)
List methods of research in neuroscience
CT scan, MRI, fMRI, DTI, PET/SPECT
