Lecture 3 Flashcards
complex network of nerve and cells that carry messages to and from the brain and spinal cord to various parts of the body
nervous system
highly specialized cell in the nervous system that is responsible for the reception, conduction, and transmission of electrochemical signals
neurons
classes of neurons
- unipolar neurons
- bipolar neurons
- multipolar neurons
neuron with one process extending from its cell body
unipolar neurons
unipolar neurons are found primarily in the _______
afferent division of the PNS
neuron type if the axon that extends from the cell body splits into two branches
pseudounipolar
neuron with two processes extending from its cell body
bipolar neurons
2 processes of bipolar neurons:
- dendrite
- axon
example of bipolar neurons
sensory neurons found in olfactory epithelium and the retina of the eye
neuron with more than two processes extending from its cell body
multipolar neurons
multipolar neurons has a ____ axon and _____ dendrites extending from the cell body
- single
- multiple
multipolar neuron in the cerebellum that has many branching dendrites but only one axon
purkinje cell
3 kinds of neurons:
- sensory neurons
- motor neurons
- interneurons
afferent neurons
sensory neurons
efferent neurons
motor neurons
(kind of neuron) neurons with a short axon or no axon at all that are located between motor and sensory pathways and are highly involved in signal integration
interneurons
(kind of neuron) transmit information away from the CNS toward some type of effector
motor neurons
(kind of neuron) transmit information from sensory receptors in the skin or the internal organs toward the CNS for processing
sensory neurons
selectively permeable or semipermeable membrane that encloses the neuron
neuron cell membrane
facilitates the transport of substances across a cell membrane
channel protein
transfer a signal to the inside of the neuron when particular molecules bind to them on the outside of the membrane
signal proteins
parts of a neuron
- cell body
- nucleus
- dendrites
- axon hillock
- axon
- myelin sheath
- nodes of rainver
- buttons
- synapses
gaps between adjacent neurons across which chemical signals are transmitted
synapses
gaps between sections of myelin facilitate the rapid conduction of nerve impulses
nodes of ranvier
long, narrow process that projects from the cell body; responsible for generating and transmitting nerve impulses
axon
cone-shaped region at the junction between the axon and the cell body
axon hillock
button-like ending of the axon branches
buttons or axon terminal
metabolic center of the neuron; contains the nucleus and other important organelles
cell body
cell body is also called _____
soma
contains the nucleolus and chromosomes necessary for the coded production of proteins within the cell
nucleus
short processes that emanate from the cell body, which receives most of the synaptic contacts from other neurons
dendrites
sites of aerobic energy release
mitochondria
clear internal fluid of cell
cytoplasm
system of folded membranes in the cell body
endoplasmic reticulum
portions of the ER responsible for protein synthesis
rough portion
portion of the ER responsible for fat synthesis
smooth portion
connected system of membranes that packages molecules in vesicles
golgi complex
internal cellular structures on which proteins are synthesized
ribosomes
internal tubules responsible for the rapid transport of molecules throughout the neuron
microtubules
membrane packages that store neurotransmitter molecules ready to release near synapses cellular structures on which proteins are synthesized; located on the ER
synaptic vesicles
molecules that are released from active neurons and influence the activity of other cells
neurotransmitters
provide support for the neurons
glial cells
how many glia are there in every three neurons
2
kinds of glial cells
- oligodendrocytes
- schwann cells
- microglia
- astrocytes
[glial cells that] have extensions that are rich in myelin, which form myelin sheaths that increase the speed of axonal conduction
oligodendrocytes
[glial cells that] build the myelin sheaths that surround and insulate certain vertebrate axons, and supply with nutrients
schwann cells
[glial cells that] responds to injury or disease by multiplying, engulfing cellular debris or even entire cells
microglia
[glial cells that] regulate blood flow and allow passage of chemicals from the blood into CNS neurons
astrocytes
oligodendrocytes are found in the ____ and ____
- brain
- spinal cord
smaller than other glial cells
microglia
(glial cells) found in the peripheral nervous system
schwann cells
astrocytes are the _____ glial cell and is ____ shaped
- largest
- star-shaped
commonly used to discover the overall shape of neurons
golgi stains
used to estimate the number of cell bodies in an area
nissl stains
captures neuronal structure in exquisite detail
electron micrograph
2 neuroanatomical tracing techniques
- anterograde tracing
- retrograde tracing
to reveal the extremely complicated connectional relationships between neurons
neuroanatomical tracing
used when an investigator wants to trace the paths of axons projecting towards the cell bodies located in a particular area
retrograde testing
used when an investigator wants to trace the paths of axons projecting away from cell bodies located in a particular area
anterograde tracing
directions in the vertebrate nervous system that is described in relation to the orientation of the spinal cord
neuroanatomical directions
three axes of the vertebrate nervous system
- anterior-posterior
- dorsal-ventral
- medial-lateral
toward the nose end
anterior
toward the tail end
posterior
toward the surface of the back or the top of the head
dorsal
toward the surface of the chest or the bottom of the head
ventral
toward the midline of the body
medial
away from the midline toward the body’s lateral surfaces
lateral
closer to the origin
proximal
farther from the origin
distal
section cut at a right angle to any long, narrow structure
cross section
major divisions of the nervous system
- central nervous system
- peripheral nervous system
division of the NS that is located within the skull and spine
central nervous system
division of the NS that is located outside the skull and spine and connects the brain and spinal cord to the body
peripheral nervous system
2 major divisions of the CNS
- brain
- spinal cord
3 broad functions of the CNS
- take in sensory information
- process information
- send out motor signals
part of the nervous system located in the skull
brain
brain is responsible for ______ most sensory information and ____ body function, both consciously and unconsciously
- integrating
- coordinating
5 major divisions of the brain
- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
forebrain includes what division of the brain
- telencephalon
- diencephalon
midbrain includes what division of the brain
mesencephalon
hindbrain includes what division of the brain
- metencephalon
- myelencephalon
most posterior division of the brain
myelencephalon
the myelencephalon is composed largely of tracts carrying ____ between the rest of the brain and the body
signals
reticular formation is sometimes referred to as _____
reticular activating system (RAS)
houses many ascending and descending tracts
metencephalon
metencephalon is part of the _____
reticular formation
2 divisions of the metencephalon
- pons
- cerebellum
lies anterior and ventral to the medulla; it contains nuclei for several cranial nerves
pons
large convoluted structure on the brain stem’s dorsal surface
cerebellum
other term for cerebellum
little brain
part of the brainstem, located between the diencephalon and the pons
mesencephalon
mesencephalon plays a crucial role in several critical functions, including:
- motor control
- sensory processing
- arousal state regulation
parts (or division) of the mesencephalon
- tectum
- tegmentum
it is the “roof”
tectum
it is the “floor”
tegmentum
dorsal portion of the midbrain involved in certain sensory and motor functions
tectum
2 pairs of bumps in mammal’s tectum
- superior colliculus
- inferior colliculus
____ is the anterior pair with visual-motor function
superior colliculus
____ is the posterior pair with auditory functions
inferior colliculus
division of the mesencephalon ventral to the tectum
tegmentum
gray matter situated around the cerebral aqueduct that mediates the analgesic effects of opioid drugs
periaqueductal gray
produce the neurotransmitter dopamine
substantia nigra gray
large structure located centrally within the tegmentum that is involved in the coordination of sensorimotor information
red nucleus
relay and processing hub for sensory information and autonomic regulation
diencephalon
divisions of diencephalon
- thalamus
- hypothalamus
large, two-lobed structure that constitutes the top of the brain stem
thalamus
regulates the release of hormones from the pituitary gland
hypothalamus
hypothalamus is located _____
below the anterior thalamus
nuclei that receive signals from sensory receptors, and then transmit them to the appropriate areas of sensory cortex
sensory relay nuclei
relay station in the visual system
lateral geniculate nuclei
relay station in the auditory system
medial geniculate nuclei
relay station in the somatosensory system
ventral posterior nuclei
synthesizes hormones that the blood carries to organs throughout the body
pituitary gland
point at which the optic nerves from each eye come together and then decussate
optic chiasm
largest division of the human brain
telencephalon
telencephalon mediates the most complex function of the brain which includes:
- initiating voluntary movement
- interpreting sensory input
- mediating complex cognitive processes such as learning, speaking, and problem solving
division of the telencephalon
cerebral cortex
divisions of the cerebral cortex
- neocortex
- hippocampus
layer of deeply convoluted tissue that covers the cerebral hemisphere
cerebral cortex
small unmyelinated neurons in the cerebral cortex
gray matter
large myelinated axons beneath the cerebral cortex
white matter
largest part of the cerebral cortex
neocortex
neocortex is also known as _____
isocortex
neocortex is the region of the brain responsible for:
- sensation
- action
- cognition
- consciousness
located at the medial edge of the cerebral cortex as it folds back on itself in the medial temporal lobe
hippocampus
hippocampus is involved in ____ and memory retrieval of two types of memory: ____ and _____
- long-term memory formation
- declarative memory
- episodic memory
large furrows in the convoluted cerebral cortex
fissures
small furrows in the convoluted cerebral cortex
sulci
ridges between fissures and sulci
gyri
major fissures
- central fissure
- lateral fissure
- longitudinal fissure
separates the frontal and parietal lobes
central fissure
laterally-located horizontal fissure separating the temporal lobe from the frontal and parietal lobe
lateral fissure
deep groove that separates the two cerebral hemispheres of the vertebrate brain
longitudinal fissure
largest cerebral commissure
corpus callosum
major gyri
- precentral gyrus
- postcentral gyrus
- superior temporal gyrus
- cingulate gyrus
prominent gyrus on the surface of the posterior frontal lobe of the brain that controls voluntary motor movement
precentral gyrus
on the lateral surface of the parietal lobe that is responsible for proprioception
postcentral gyrus
situated at the topmost aspect of the temporal lobe involved in auditory processing
superior temporal gyrus
arch-shaped convolution situated just above the corpus callosum
cingulate gyrus
4 lobes of the brain
- frontal lobe
- temporal lobe
- parietal lobe
- occipital lobe
(lobe of the brain) responsible for voluntary motor and cognitive functions
frontal lobe
(lobe of the brain) responsible for integrating sensory information and proprioception
parietal lobe
(lobe of the brain) interpret and remember complex auditory information and deals with long-term memory
temporal lobe
(lobe of the brain) caters the primary visual cortex that functions as a visual processing region, interpreting the information that the eyes perceive
occipital lobe
circuit of midline structures that circle the thalamus
limbic system
major structures of the limbic system
- amygdala
- fornix
- cingulate cortex
- septum
- basal ganglia
- cerebral commisures
almond-shaped nucleus in the anterior temporal lobe
amygdala
amygdala is involved in _____
emotion
major tract of the limbic system
fornix
midline nucleus located at the anterior tip of the cingulate cortex
septum
plays a role in the performance of voluntary motor responses and decision making
basal ganglia
tracts spanning the longitudinal fissure that directly connect the cerebral hemispheres
cerebral commisures
part of the nervous system that is located in the spine
spinal cord
spinal cord is a ___, ____, tubular bundle of nervous tissue protected by the vertebrae
- long
- thin
4 major regions: the spinal cord
- cervical
- thoracic
- lumbar
- sacral
mixed nerves connecting the spinal cord to muscles, organs, and tissues throughout the body
spinal nerves
parts of pns
- somatic nervous system
- autonomic nervous system
part of the pns that interacts with the external environment
somatic nervous system
main function of the somatic nervous system
to control all voluntary movements
afferent nerves carry sensory signals or impulse from the skin, sensory organs, and skeletal muscles to the CNS
afferent pathway
efferent nerves carry motor signals from the CNS to the skeletal muscles
efferent pathway
part of the PNS that regulates the body’s internal environment and involuntary responses
autonomic nervous system
consists of autonomic motor nerves that project from the CNS in the lumbar and thoracic regions of the spinal cord
sympathetic nervous system
consists of autonomic motor nerves that project from the brain and sacral region of the spinal cord
parasympathetic nervous system
intricate layers that surround and safeguard the brain
meninges
outermost layer which provides a tough protective barrier against external forces
dura mater
regulates the flow of cerebrospinal fluid and cushions the brain
arachnoid mater
houses the cerebrospinal fluid, providing vital nourishment and waste removal
subarachnoid mater
innermost layer which directly adheres to the brain, supplying it with oxygen and nutrients
pia mater
four large internal chambers of the brain
ventricles
fills the subarachnoid space, the central canal of the spinal cord, and the cerebral ventricles of the brain
cerebrospinal fluid (CSF)
a selectively permeable shield that guards the brain from harmful substances
blood brain barrier
contributes to the maintenance and integrity of the blood- brain barrier
astrocytes
blood brain mechanism
- tight junctions formation
- astrocytes take charge
- meticulous substance regulation
