sensory input
any electrical impulse sent from the sensory organs (the eyes, ears, nose, tongue, and skin) to the central nervous system (CNS)
integration
the CNS subconsciously processes and interprets the information received through the sensory organs
motor output
the CNS transmits messages to effectors, which are muscles or glands in the body that generate a response that occurs through the voluntary movement produced by skeletal muscle, or through the involuntary movement of muscles and glands
neurons (nerve cells)
fundamental cells of the nervous system, are found in the brain, spinal cord, and peripheral nerves, and are responsible for conducting electrical impulses throughout the body in response to an external or internal stimulus
sensory neurons
conduct electrical signals (impulses) from various parts of the body to the brain and the spinal cord
motor neurons
receive electrical impulses from the brain and spinal cord and communicate these impulses to other parts of the body
astrocyte
a large, star-shaped cell that holds nerve cells in place and helps them develop and work the way they should
electrochemical signaling
process of impulse transmission via the neurons
nerves
when many neurons form a bundle of fibers, the fibers are called ____
cell body
contains nucleus, cytoplasm, mitochondria, and organelles of nerve cells
dendrites
extend from the neuron cell body and receive the electrical impulses, or messages, from other neurons
axon
more commonly known as ânerve fibers,â they are long, thin nerve processes (projections) that transmit electrical impulses from the cell body of the neuron out toward the ____ terminals
myelin sheath
made up of fats and proteins; provides electrical insulation for the axons as they conduct neural (nerve) impulses
axon terminals
axons branch out from the cell body, ending in ____
synapse
contact point at which one neuron communicates with another
synaptic cleft
a microscopic gap between two neurons
neurotransmitters
chemical messengers that pass neural impulses across a synaptic cleft from one neuron to another
neuroglial (glial) cells
specialized cells that support the vital functions of the nervous system; provide protective insulation for the neurons and are the âglueâ that hold the nerves together, but they do not conduct neural impulses; PNS and CNS
microglial cells
found in the CNS; remove damaged neurons and infections and are important for maintaining the health of the CNS
Schwann cell
myelinates the peripheral nervous system (PNS)
oligodendrocyte
myelinates the central nervous system (CNS)
central nervous system (CNS)
comprises the brain and the spinal cord; receives, processes, and responds to impulses from all over the body; command center of the body; constantly monitors internal and external environmental stimuli and regulates cognitive and motor responses to help the body maintain homeostasis
peripheral nervous system (PNS)
made up of nerves that reach into and extend from the brain and the spinal cord; functions as the liaison between the central nervous system and the rest of the body; includes cranial and spinal nerves that conduct impulses from sensory receptors to the CNS and from the CNS to muscles, organs, glands, and skin
cranial nerves
conduct neural impulses to and from the brain
spinal nerves
transmit neural impulses to and from the spinal cord
nodes of Ranvier
gaps between myelin sheaths in glial cells of the PNS
gray matter
unmyelinated nerve tissue that is composed mostly of nerve cell bodies and dendrites; found in outer cerebral cortex and inner spinal cord
white matter
contains myelin sheaths, which shroud axons, and are made by neuroglial cells; outer cortex, exterior spinal cord; contains microglial cells
nerve tract
bundles of nerve fibers
cerebrum
located in the superior and anterior parts of the brain, is the largest brain region; seat of high-level cognitive functions such as language, reasoning, planning, memory, and sensory integration
cerebral cortex
layer of gray matter contains many folds of convoluted (curved) and fissured (depressed) areas that increase the brainâs surface area, enabling the brain to process the information that is constantly being received by the sensory organs
gyri
convolutions in the cerebral cortex
sulci
depressions in the cerebral cortex
left brain
right side of body control, number skills, math/scientific skills, written language, spoken language, objectivity, analytical, logic, reasoning
right brain
left side of body control, 3-D shapes, music/art awareness, intuition, creativity, imagination, subjectivity, synthesizing, emotion, face recognition
corpus callosum
connects right and left brain hemispheres; 200-300 million neurons thick
frontal lobes
control movement, reasoning, planning, problem solving, speech, emotions, and are your personality
Broccaâs area
where 97% of all expressive language comes from
pre-frontal cortex
emotions attached to music; gatekeeper of inhibitions
motor strip
moving body parts
parietal lobes
situated in the superior part of the cerebrum; largely responsible for processing sensory stimuli related to touch, pressure, temperature, and pain; mid-term memory
sensory strip
processes sensory stimuli and sensory input to motor output
parietal proper
goal-directed movement, binary math, sensory analysis, analogies, comparisons, attention span, cause/effect
occipital lobes
vision or visual fields, reading, sight words, main memorization, visual memories, spatial relation, drawing, color, night vision, peripheral vision
temporal lobes
hearing, sense of smell, factual and visual memory, language processing â Wernicke
cerebellum
second largest region of the brain; located posterior to the cerebrum, behind the brain stem; controls your bodyâs sense of balance and equilibrium, and it coordinates movement of voluntary muscles
diencephalon
site of three key endocrine glands: thalamus, hypothalamus, pineal gland
thalamus
touch, processing, memory, memory function as a part of learning
hypothalamus
control center for ANS functions such as heart rate, blood pressure, body temperature, breathing, hormone production, hunger, thirst, and digestion, instincts, reflexes, thrill seeking, sexual desire, and orgasm
pineal gland
secretes melatonin, a hormone that helps regulate the bodyâs circadian rhythm
hippocampus
short term memory acquisition, orientation, sense of direction, memorization
amygdala
higher order emotions such as rage, jealousy, shame, PTSD, embarrassment, and response to rewards
pituitary gland
master gland, secretes many hormones; critical to respond appropriately to the environment; physical and sexual development (body can send signals with hormones)
pons
connects the cerebellum to the rest of the brain; coordination, equilibrium, balance; breathing rhythm
reticular activating system (RAS)
flight-or-flight response from sympathetic system, awareness or alertness, amount and flow of sensory input
medulla oblongata
(backup) connects the brain to the spinal cord via the pons; helps conduct neural impulses from the brain to the spinal cord and regulates vital autonomic functions such as breathing, heart rate, blood pressure, and body temperature
midbrain
serves as the passageway for electrical impulses as they travel between the brain and the spinal cord
medulla (brain stem)
connects the cerebrum with the spinal cord; helps regulate the central nervous system by serving as a conduit for sensory information carried between the cerebrum or the cerebellum and the rest of the body; governs vital functions such as respiratory rate, cardiac rhythm, body temperature, and sleep patterns
cerebrospinal fluid (CSF)
fills four cavities of the brain called ventricles; clear, watery fluid; envelops and protects the delicate brain and spinal cord tissues from injury
choroid plexus
manufactures cerebrospinal fluid in each ventricle of the brain
spinal cord
column of neural tissue that extends inferiorly from the medulla oblongata; divided into 31 segments that each contain a pair of spinal nerves and connect the CNS to the organs and tissues of the upper body and the limbs; provides support for the body and helps it to maintain equilibrium; protected by cerebrospinal fluid that flows through the central canal of the spine; exterior is white matter, interior is gray matter
ascending spinal tract
white matter is made up of the ____, which transmits sensory information from organs and glands to the brain
descending spinal tract
white matter is made up of the ____, which relays motor commands from the brain to one or more of the peripheral nerves
meninges
layers of connective tissue that protect the CNS
dura mater
Latin for âtough motherâ; thick sac of dense collagen fibers and blood vessels that protects the CNS from injury; also contains cerebrospinal fluid, and it supplies blood to the nervous tissue of the CNS
pia mater
âsoft motherâ; a thin, delicate tissue membrane that lies directly on the brain and the spinal cord; contains a rich supply of blood vessels that nourish the CNS
arachnoid mater
means âspider-like motherâ because this layer of the meninges contains many thin fibers that connect it to the pia mater below it; these fibers cross the sub-____ space between the ____ mater and the pia mater
sub-arachnoid space
filled with protective fluid
afferent nerves
nerves that conduct messages from sensory receptors to the CNS only
efferent nerves
conduct messages from the CNS to the muscles or glands of the body
autonomic nervous system (ANS)
controls the involuntary (unconscious) bodily functions
sympathetic nervous system
controls the bodyâs âfight-or-flightâ response in times of crisis; gives a ârushâ of adrenaline that equips your body to confront or flee from a threatening situation
parasympathetic nervous system
controls the ârest-and- digestâ response that counteracts the adrenalized response generated by the sympathetic nervous system during a fight-or-flight experience; âcalmsâ the body with signals that decrease heart rate and respirations and that resume digestion
somatic nervous system (SNS)
involves the skeletal muscles and the skin; controls the conscious, voluntary activities of the body; nerves send messages about pain, pressure, temperature, and touch to and from the brain and spinal cord