Science Flashcards
neuron
- nerve cell (eukaryotic cell)
- main cell for communicating across long distances
nucleus
- neurons have a nucleus
- where the DNA is stored
DNA
- deoxyribonucleic acid
- encodes the instructions to build proteins that are the building blocks for organisms
soma
- cell body
- where the nucleus and other organelles are found
neuronal membrane
- the layer that separates the neuron from the outside space
dendrite
- receive synaptic inputs from other neurons
- size and shape impact how it receives inputs
- branch out
- connected to the cell body/soma
axon
- long “wire” that transmits electrical signals or release packets of chemical transmitters from the neuron
- uniform thickness, some branch, no organelles
myelin
- a fatty substance formed by glial cells to insulate the axons
- when covering an axon, it can speed up the conduction of the neuron’s electrical signals
Nodes of Ranvier
- small gaps in the myelin that allow the axon to gain access to fluid outside the cell and send signals
axon hillock
- where the axon begins at the soma
axon terminals
- where the axon ends and releases the signal in the form of a neurotransmitter
synapse
- where one neuron communicates with another neuron
synaptic cleft
- the space between two neurons where a signal is passed
presynaptic neuron
- first neuron in the synapse
postsynaptic neuron
- second neuron that receives the signal
neurotransmitters
- signalling chemicals
interneurons
- neurons that work to connect with neurons with each other within the nervous system
grey matter
- tissue made of cell bodies and dendritic arbors of neurons
- located on the outside in the brain, but inside in the spinal cord
white matter
- tissue made of myelinated axons of the neurons
- located on the inside in the brain, but outside in the spinal cord
glial cells
- non-neuronal cells found in the nervous system
- produced throughout the life of the organism
oligodendrocytes
- myelinating glia that form sheaths around axons in the central nervous system
Schwann cells
- myelinating glia that form sheaths around axons in the peripheral nervous system
astrocyte
- regulates the chemical makeup of the extracellular fluid in the space of the cells in the nervous system
- Has long extensions that wrap around blood vessels in the brain to form the blood brain barrier
- most common type of glial cell
microglia
- immune cells of the neuron, protect neurons from toxins/disease/ invaders
- clear away pathogens or dead/ damaged neurons by consuming them
meninges
- the three layers that protect the central nervous system
dura mater
- outermost layer
- thick, leathery material
epidural space
- space between the dura mater and the skull that contains fats which absorb shocks to the head
arachnoid membrane
- right under the dura mater
- long, stringy components
subdural space
- between the dura mater and arachnoid
- if there is trauma, then blood pools here and puts pressure on the brain
subarachnoid space
- space just below the arachnoid
- filled with cerebrospinal fluid to cushion the brain
- allows blood vessels to access the brain and deliver nutrition
pia mater
- innermost layer
- thin, follows every groove of the brain to prevent CSF from entering the brain
- allows blood vessels to travel
cerebrum
- contains most of the regions of the brain
frontal lobe
- largest in the brain, located in the front of the human head
- contains regions related to complex thinking or cognition
motor cortex
- brain plans and sends out instructions for the movements to the rest of the body
- located in the back edge of the frontal lobe
prefrontal cortex
- the regions in front of the motor cortex
parietal lobe
- located just behind the frontal lobe
- processes the sense of touch from the body, skin, and organs, temperature, pain, and body position
- Understands spatial relations
occipital lobe
- back of the cerebrum
- process and analyze visual information from the eyes
temporal lobe
- located on both sides of the brain, one under each ear and near the temples
- important for auditory sound and speech processing, music, memory, and object recognition
cerebellum
- structure that sits underneath the cerebrum
- helps the organism learn smooth and coordinated movements and new kinds of movements
gyri
- bumps on the surface of the brain
sulci
- the grooves/folds on the surface of the brain
subcortical structures
- structures that are found underneath cerebral cortex, each region is found on both the right and left side of the brain
amygdala
- found in the temporal lobe
- major component of the limbic system, regulates emotion and fear, processes threats, stress, reward, and arousal
hippocampus
- crucial region for long-term memory and spatial navigation
- Part of the limbic system, first areas to suffer cell death in Alzheimer’s
- memory consolidation
memory consolidation
- the change of short-term memories into long-term memories
thalamus
- central of the cerebral hemisphere
- all input from the body must first travel through this region before going to the brain – smell is the only exception, goes to the amygdala
- plays a role in consciousness, emotional behaviors, motor control, and cognition
pituitary gland
- releases important growth hormones, right next to the hypothalamus
hypothalamus
- located right below the thalamus
- mediates the action of the pituitary gland and unconscious functions needed for homeostasis
homeostasis
- keeping the body’s systems in a balanced and healthy state
basal ganglia
- cluster of nuclei found in the center of the cerebral hemispheres underneath the thalamus
- Made of the caudate nucleus, putamen, and globus pallidus
- help planned, voluntary movements or prevent unwanted or excess movements
brainstem
- located at the bottom of the brain, stalk that connects the brain to the spinal cord
- thalamus sits right on top of it
midbrain
- topmost part
- contains nuclei that help regulate eye movement and pupillary light reflex
- integrate visual information from the eyes with the auditory information from the inner ear
pos
- middle part
- contains nuclei for coordinating facial movements, chewing muscles, hearing, and balance
medulla
- bottom part
- contains nuclei dedicated to relaying touch sensations from the face, swallowing food, and vomiting to regulating blood pressure, heart rate, and breathing
spinal cord
- the other main section of the central nervous system, encased in vertebrae that make up the spine, conducts information between the brain and body
cervical spinal cord
- top section of the spinal cord
- innervates the arm, neck, and shoulders
thoracic spinal cord
- carries information to and from the chest and torso
lumbar spinal cord
- innervates the hips and front of the legs
sacral spinal cord
- innervates the buttocks, back of the legs, and genitalia
ventricular system
- series of open holes or cavities inside the central nervous system filled with cerebrospinal fluid
peripheral nervous system
- consists of nerves or axons and some clusters of cell bodies (ganglia) that leave the CNS to relay information from the brain to the body
somatic nervous system
- all the axons leaving and entering the spinal cord that that bring information to and from the tissues of your body
- under voluntary control
autonomic nervous system
- controls involuntary responses to regulate all kinds of aspects of the brain and body
Regulates the function of your internal organs, smooth muscle (such as the ones found in hearts), and glands
sympathetic nervous system
- responsible for the “fight or flight” response
- activated by adrenal glands, produces stress and prepares body for it
parasympathetic nervous system
- response for “rest and digest”
- when activated the organism is focused on digesting food, growth and cell division, immune responses, energy storage, and other aspects of maintaining homeostasis
resting membrane potential
- the electrical charge inside the neuron when the neuron/glia is not sending any signals
neuronal membrane
- selective phospholipid bilayer
- allows ionic concentration to be different inside vs. outside the cell due to its selectivity
passive transport
- an ion moves from one side to the other side of the membrane due to a natural force, usually the concentration gradient
ionic concentration
- number of ions in a particular volume of water forming a solution
concentration gradient
- measurement of how the concentration of something changes from one side of the neuronal membrane to another
electric potential
- the neuronal membrane may also have a difference in electric charges of the ions on either side
ion channels
- proteins that form specialized openings in the neuronal membrane through which ions can pass
gating
- a molecule triggers the channel to open
voltage-gated ion channels
- open and close when the membrane potential is a certain voltage
ligand-gated ion channels
- open when a particular molecule binds to a specific location on the channel
active transport
- ion is moved using energy from one side of the membrane to the other and has to go against the concentration gradient
ion pump
- a type of channel that uses energy to move ions from one side to the other
sodium-potassium pump
- crucial for neurons for establishing the resting membrane potential
chemical driving force
- result of the concentration gradient that causes ions to diffuse out of the cell
equilibrium potential
- membrane potential at which a particular ion reaches a equilibrium point
rising phase
- membrane potential becomes more positive due to the influx of positive ions (depolarization)
action potential
- the electric potential across the neuronal membrane when the neuron is active and firing, caused by the rapid opening and closing of ion channels
overshoot of the action potential
- membrane potential continues to increase even after it’s been reached, becomes around +30 mV to +40 mV
falling phase
- membrane potential becomes more negative due to positive ions leaving the cell (repolarization or hyperpolarization)