CH2: Cells and Structures Flashcards
What are the four zones of the neuron and their corresponding structures?
1) Input zone: dendrite first; where neurons collect and integrate information, either from the environment or from other cells
2) integration zone: cell body (soma); where the decision to produce a neural signal is mad
3) conduction zone: axon (nerve fiber); where information can be transmitted over great distance
4) output zone: axon terminals; where the neuron transfers information to other cells
Dendrite
An extension of the cell body that receives information from other neurons
Cell body
Also called soma. The region of a neuron that is defined by the presence of the cell nucleus
Axon
Also called nerve fiver. A single extension from the nerve cell that carries action potentials from the cell body toward the axon terminal
Axon terminal
Also called synaptic bouton. The end of of an axon or axon collateral, which forms a synapse with a neuron or other target cell
Motoneuron
Also called motor neuron. A neuron that transmits neural messages to muscles (or glands)
Sensory neurons
A nerve cell that is directly affected by changes int he environment, such as light, odor, or touch
Interneuron
A nerve cell that is neither a sensory neuron or a motoneuron; interneurons receive input from and send output to other neurons
What are the 3 general shapes of neurons?
Multipolar neurons, bipolar neurons, and unipolar neurons
Multipolar neuron
A nerve cell that has many dendrites and a single axon. They are the most common type of neuron
Bipolar neuron
A nerve cell that has a single dendrite at one end and a single axon at the other end. They are common in sensory systems, such as vision
Unipolar neuron
A nerve cell with a single branch that leaves the cell body and then extends in two directions; one end is the input zone, and the other end is the output zone. Unipolar neurons transmit touch information from the body into the spinal cord
What are 3 components of the synapses
Presynaptic membrane, postsynaptic membrane, and a synaptic cleft
Presynaptic membrane
The specialized membrane on the axon terminal of a nerve cell that transmits information by releasing neurotransmitter
Postsynaptic membrane
The specialized membrane on the surface of a neuron that receives information by responding to neurotransmitter from a presynaptic neuron
Synaptic cleft
The space between the presynaptic and postsynaptic neurons at a synapse.
Synaptic vesicle
A small, spherical structure that contains molecules of neurotransmitter
Neurotransmitter
The chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons
Neurotransmitter receptor (or just receptor)
A specialized protein, often embedded in the cell membrane, that selectively senses and reacts to molecules of a corresponding neurotransmitter or hormone
Neuroplasticity
The ability of the nervous system to change in response to experience or the environment
Axon hillock
The cone-shaped area on the cell body from which the axon originates
Innervate
To provide neural input to; electrical signals race down the axon toward the targets
Axon collateral
A branch of an axon
Axonal transport
The transportation of materials from the neuronal cell body toward the axon terminals, and from the axon terminals back toward the cell body
Glial cells
Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain
What are the four types of glia cells
Oligodendrocyte, Schwann cells, astrocyte, and microglial cells
Oligodendrocytes
A type of glial cell that forms myelin in the peripheral nervous system
Schwann cell
A type of glial cell that forms myelin in the peripheral nervous system
Myelin
A fatty insulation around an axon, formed by glial cells. This sheath boosts the speed at which nerve impulses are conducted
Node of Ranvier
A gap between successive segments of the myelin sheath where the axon membrane is exposed
Astrocyte
A star-shaped glial cell with numerous processes (extensions) that run in all directions
Microglial cells
Extremely small motile glial cells that remove cellular debris from injured or dead cells
What can of problems can glial cells cause?
Glial cells can dived in adulthood which can rise to deadly tumors. Some glial cells, astrocytes, respond to brain injury by changing size-swelling. It damages neurons and is responsible for many symptoms of brain injuries
Edema
The swelling of tissue in response to injury
Gross neuroanatomy
Anatomical features of the nervous system that are visible to the naked eye
Central nervous system (CNS)
The portion of the nervous system that includes the brain and the spinal cord.c
Peripheral nervous system (PNS)
The portion of the nervous system that includes all the nerves and neurons inside the brain and the spinal cord.
Nerve
A collection of axons bundled together outside of the CNS
Motor nerve
Transmit information from the spinal cord and the brain to the muscles and glands
Sensory nerves
Convey information from the body to the CNS
What are the two divisions of the peripheral nervous system?
The somatic nervous system and the autonomic nervous system
Somatic nervous sytem
A part of the peripheral nervous system that supplies neural connections mostly to the skeletal muscles and sensory systems of the body. It consists of cranial nerves (12 pairs) and spinal nerves (31 pairs).
The main pathway through which the brain controls movement and receives sensory information from the body and from the sensory organs of the head.
Autonomic nervous system
A part of the peripheral nervous system that provides the main neural connections to glands and to smooth muscles and organs. We have little conscious, voluntary control over it’s action. The autonomic nervous system are performed by two major divisors - the sympathetic and parasympathetic nervous system
Cranial nerves
A nerve that is connected directly to the brain. A lot have to do with facial muscles
Name the divisions of the autonomic nervous systems.
Sympathetic and parasympathetic nervous system.
Sympathetic nervous system
The part of the autonomic nervous system that acts as the “fight or flight” system, generally activating the body for action.
All originate in the spinal cord. It consists of the sympathetic ganglia and axons that lead to the organs.
Ganglion -> adrenal gland (norepinephrine and epinephrine (arousing neurotransmitters, adrenaline))
Ex. Pupils dilates, salivation is inhibited, hear rate increase, digestion is inhibited, etc
Parasympathetic nervous system
The part of the autonomic nervous system that generally prepares the body to relax, recuperate, and prepare for future action - ‘rest and digest’ response.
Arises from both the brain and the sacral parts of the spinal cord.
Uses Cholinergic neurons (acetylcholine (ACh)): slows the body
Ex. Contracts pupil, stimulates salivation, constricts airways, slow heartbeat, etc.
What are the four lobes?
Frontal, parietal, temporal, and occipital lobes
Frontal lobes
The most anterior portion of the cerebral cortex and is divided by the central sulcus. Broadly specializes in language production and motor
Parietal lobe
The large region of cortex lying between the frontal and occipital lobes in each cerebral hemisphere. It host central sulcus, involve in post central gyrus. It broadly specialize in somatic sensory
Temporal lobe
The large lateral region of the cortex in each cerebral hemisphere. It is along the sylvian fissure. It primary specialize in auditory cortex, and also language
Occipital lobe
A large region of cortex that covers much of the posterior part of each cerebral hemisphere. It primarily specialize in visual cortex
Cerebral hemisphere
One of the two halves - right or left- of the brain
Cerebral cortex
The outer covering of the cerebral hemispheres, which consists largely of nerve cell bodies and their branches. The outside wriggly part and is either called gurus (ridges) or sulcus, sylvian fissure, or central sulcus
gyrus
a ridged or raised portion of a convoluted brain surface
sulcus
a crevice or valley of a convoluted brain surface
sylvian fissure
a deep fissure that separates the temporal lobe
central sulcus
a fissure that divides the front lobe from the parietal lobe
horizontal plane
divides the brain into upper and lower parts
sagittal plane
the plane that divides the body into right and left halves
coronal plane
the plane that divides the body into front (anterior) and back (posterior part)
corpus callosum
the main band of axons that connects the two cerebral hemispheres; considered a white matter
gray matter
areas of the brain that are dominated by cell bodies and lack of myelin. gray matter mostly receives and processes information.
white matter
a light-colored layer of tissue, consisting mostly of myelin-sheathed axons, that lies underneath the gray matter of the cortex. white matter mostly transmits information
pyramidal cell
a type of large nerve cell that has a roughly pyramid-shaped cell body and is found in the cerebral cortex
cortical column
one of the vertical columns that constitute the basic organization of the cerebral cortex
basal ganglia
considered the gray matter. plays a critical role in the control of movement
limbic system
a loosely defined, widespread group of brain nuclei that innervate each other and form a network. involved in emotion and learning.
amygdala
consists of several subdivisions with quite diverse functions, including emotional regulation and the perception of odor
hippocampus and fornix
they are important for learning and memory
cingulate gyrus
implicated in many cognitive functions, including the direction of attention
olfactory bulb
involved in the sense of smell
hypothalamus
helps govern highly motivated behaviors like sex and aggression, and to regulate the hormonal systems of the body
what is the main function of the cerebellum?
cerebelllum is a structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement, and in some forms of learning
what are the structures that make up the limbic system?
amygdala, hippocampus, fornix, cingulate gyrus, and olfactory bulb.
what are the structures that make up basal ganglia?
caudate nucleus, globus pallidus, and putamen found deep within the cerebral hemispheres.
cerebrospinal fluid (CSF)
the fluid that fills the verebral ventricles. brains floats in CSF, cushioning it from minor blows to the head. it is also important materials, such as nutrients and signaling checimals
how does CSF flow through the ventricular system?
there care series of chambers in the brain called the ventricular system. each hemisphere of the brain contains a lateral ventricle extending into all four lobes of the hemisphere. the lateral ventricles are lined with a specialized membrane called the choroid plexus, which produces CSF by filtering blood. the CSF flows from the lateral ventricles into a midline third ventricle and continues down a narrow passage to the fourth ventricle. just below the cerebellum, three small opening allows CSF to exit the ventricular system and circulate over the outer surface of the brain and spinal cord
ventricular system
a system of fluid-filled cavities inside the brain
lateral ventricle
a complex c-shaped lateral portion of the ventricular system within each hemisphere of the brain
choroid plexus
a specialized membrane lining the ventricles that produce cerebrospinal fluid (CSF) by filtering blood
third ventricle
the midline ventricle that conducts cerebrospinal fluid from the lateral ventricles to the fourth ventricle
fourth ventricle
the passageway within the pons that receives cerebrospinal fluid (CSF) from the third ventricle and releases it to surround the brain and spinal cord
cerebral arteries
the three pairs of large arteries within the skull that supply blood to the cerebral cortex
blood-brain barrier
probably evolved to help protect the brain from infections and blood-borne toxins, but it also makes the delivery of drugs to the brain more difficult
stroke
damage to a region of brain tissue that results from the blockage or rupture of vessels that supply blood to that region
transient ischemic attack (TIA)
a temporary blood restriction to the part of the brain that causes strokelike symptoms that quickly resolve, serving as a warning of elevated stroke risk
what are some differences between CT and MRI scans?
MRI provides higher-resolution images and has fewer damaging effects than CT
computerized axial tomography (CAT or CT)
uses x-ray energy to generate images. the scans are medium-resolution and are useful for visualizing problems such as strokes, tumors, and cortical shrinkage
Magnetic resonance imaging (MRI)
uses magnetism and radio-frequency energy to create images of the gross structure of the living brain. MRI images can reveal subtle changes in the brain, such as the loss of myelin that is characteristic of some diseases
functional MRI (fMRI)
magnetic resonance imaging that detects changes in blood flow and therefore identifies regions of the brain that are particularly active during a given task.
generates images of the brain’s activity rather than details of its structure. offering both reasoning speed and good sharpness.
reveals how networks of brain structures collaborate on complex cognitive processes
positron emission tomography (PET)
a brain imaging technology that tracks the metabolism of injected radioactive substances in the brain, in order to map brain activity.
provides a means to visualize the brain’s activity during behavioral tasks.
cant match the detailed resolution of fMRI, but it tends to be faster and thus better able to track quick changes in brain activity.
transcranial magnetic stimulation (TMS)
a noninvasive technique for examining brain function that applies strong magnetic fields to stimulate cortical neurons, in order to identify discrete areas of the brain that are particularly active during specific behaviors.
magnetoencephalography (MEG)
a noninvasive brain-imaging technology that creates maps of brain activity during cognitive tasks b measuring tiny magnetic fields produced by active neurons.
how should neural imaging be used?
laws, law enforcement (lie detection); military; job interviews, college applications; advertising & compaiging
