Chapter 2 - Neuro Functionality Flashcards
What are neurons in the nervous system?
The communicators of the nervous system, the basic unit of the nervous system, are each composed of a cell body, a receptive component called a dendrite, and a transmitting component called an axon.
What are Glial Cells?
They provide support for and contribute to information processing neurons, it is also called glia or neuroglia. It is a nonneural brain cell that provides structural, nutritional, and other types of support to the brain.
What is the Neuron Doctrine?
The hypothesis is that the brain is composed of cells that are distinct structurally, metabolically, and functionally.
What are Synapses?
The tiny gap between neurons where information is passed from one to the other.
What is a cell body in a neuron?
It is also called soma. The region of a neuron that is defined by the presence of the cell nucleus
What are some types of organelles in the Cell Body?
- Mitochondria - Produces energy.
- Cell Nucleus - Contains genetic material.
- Ribosomes - translates genetic instructions into proteins.
What are the four distinct zones structures that are directly related to info processing?
- Input Zones
- Integration Zones
- Conduction Zones
- Output Zones
What is an Input Zone?
The dendrites are a part of this zone and allow for the information to be received via the synapses of other neurons. The dendrite can be elaborate to connect with other neurons.
What are Integration Zones?
The information is then integrated by the cell body, combining the information the neuron has received to determine whether or not to send a signal of its own.
What are Conduction Zones?
The axon carries the neuron’s electrical signals away from the cell body. Before the axon ends it splits into multiple branches called axon collaterals.
What are Output Zones?
At specialized ends of the axon called axon terminals - where synapses form -, the activity of the neurons is transmitted across the synapses to other cells.
What are the different classifications of info processing neurons?
- Multipolar Neurons
- Bipolar Neurons
- Unipolar Neurons
What is Multipolar Neuron?
These neurons have many dendrites and a single axon, they are the most common type of neuron.
What is a Bipolar Neuron?
These have a single dendrite at one end of the cell and a single axon at the other end.
This type of neuron specializes in sensory systems, such as vision. So it is especially common in these systems.
What is a Unipolar Neuron?
(also called monopolar) have a single extension, usually thought of as an axon, that branches in two directions after leaving the cell body.
One end is the input zone with branches like dendrites; the other, the output zones. Such cells transmit touch information from the body to the spinal cord.
What is an Interneuron?
A neuron that is neither a sensory neuron nor a motor neuron; receives input from and sends output to other neurons
What is a Motor Neuron?
A nerve cell that transmits motor messages, stimulating muscles or glands
What is a Sensory Neuron?
A neuron that is directly affected by changes in the environment, such as light, odor, or touch
What are Dendrites?
It’s like a branch-like arborization (the elaborate branching of the dendrites of some neurons)
What does Presynaptic mean?
Referring to the region of a synapse that releases the neurotransmitter
What does Postsynaptic mean?
Referring to the region of the synapses that receives and responds to neurotransmitters
What three principle components do synapses break down into?
- Presynaptic Membrane/cell
- Synaptic Cleft
- Postsynaptic Membrane/cell
What is the Presynaptic Membrane?
The specialized membrane of the axon terminal of the neuron transmits information by releasing a neurotransmitter
What is the Synaptic Cleft?
The space between the presynaptic and postsynaptic membranes
What is the Postsynaptic Membrane?
The specialized membrane on the surface of the cell receives information by responding to neurotransmitters from a presynaptic neuron
What are Synaptic Vesicles?
A small, spherical structure that contains molecules of neurotransmitters
What are Neurotransmitters?
chemicals that are released from an axon terminal to communicate with other neurons -
What are Receptors?
A protein that binds and reacts to neurotransmitters or hormones
What is Neural Plasticity?
Which is the ability of the nervous system to change in response to experience or the environment
In what ways can information move through an axon?
- Anterograde Transport (toward axon terminal)
- Retrograde Transport (toward the cell body for recycling)
The axon has two speeds for electrical signals, what are they?
- rapid outside the axon
- slow inside the axon
What do Glial cells do?
Support and enhance neural activity, they communicate with each other and with neurons
What are the four types of Glial cells?
- Astrocytes
- Microglial
- Oligiodenrocytes
- Schwann Cells
What do Astrocytes do?
Largest glia, is star-shaped, with many functions such as regulation of blood flow and synapses formation and pruning, function, and maintenance. They can attach to blood vessels and help communication between neurons.
What is a Microglial involved with?
It is involved in response to injury or disease and synaptic pruning during development.
What does Phagocytosis do?
Engulfing and ingestion of other materials (dead cells)
What do Oligiodenrocytes do and where is it located?
In the CNS oligodendrocytes provided myelin
What does a Schwann Cell do and where is it located?
In the PNS Schwann, cells provide myelin
What is Myelin?
Myelinating glial cells wrap around the axon forming a myelin sheath. The Nodes of Ranvier are gaps between segments of myelin.
What do Glial cells continue to do through a life that neurons do not?
they divide continually
When Astrocytes respond to brain injury what do they do?
They increase in size and cause swelling. Can cause
-Edema, a condition characterized by an excess of watery fluid collecting in the cavities or tissues of the body
It is also involved in regulating brain chemistry
-implicated in epilepsy
What is Microglial possibly involved in?
Alzheimer disease
What is Gross Neuroanatomy?
Features of the nervous system visible to the naked eye
What is the Peripheral Nervous System?
All parts of the nervous system found outside the skull and spinal column
What is the Central Nervous System?
Consists of the Brain and the Spinal cord
What does the PNS consist of?
The PNS consists of nerves or bundles of axons
- Some nerves, motor nerves, transmit information from the CNS to the muscles, organs, and glands. (efferent nerves)
- Others, sensory nerves, convey information from the body to the CNS (afferent nerves)
What is the Somatic Nervous System?
Nerves that interconnect the brain and the major muscles and sensory systems
Cranial nerves and spinal nerves
What is the Autonomic Nervous System?
- Nerves that primarily control the viscera (organs)
- Controls the organs of the body
- Autonomic ganglia - bundles of nerve cell bodies
- Connect peripheral and CNS
- Preganglia - in the CNS
- Postganglia - in the PNS
What are the Three Major Divisions of the Autonomic Nervous System?
- Sympathetic Nervous system (Fight or Flight)
- Parasympathetic Nervous System (Rest and Digest)
- Entric Nervous System (The Guts Brain)
What is the Sympathetic Nervous system and how does it affect our body in fight or flight?
It is our fight or flight response and it affects our body by:
- Dilates Pupils
- Inhibits salivation
- Relaxes airways
- Accelerates heartbeat
- Inhibits digestion
- Constricts blood vessels in the skin
What is the Parasympathetic Nervous System and how does it affect our body in rest and digestion?
It is our rest and digest response and it affects our body by:
- Constricts pupils
- Stimulates salvation
- Constricts airways
- Slows heartbeat
- Stimulates digestion
- Dilates blood vessels in the skin
What is the Enteric Nervous System and how does it affect our body?
It is our guts brain and it affects our body by:
- Regulates the function of the gut
- Located in the sheaths of tissue in the esophagus, stomach, small intestine, and colon
- Maintains fluid and nutrients in the body
- Under control of CNS
What do Spinal Nerves do?
Carry sensory information from the body (mostly skin) to the CNS, and carry motor information from the CNS to muscles and glands.
What root does Sensory info and Motor info go through?
Sensory Info comes via the Dorsal root
Motor Info comes via the Ventral root
What are the characteristics of the brain?
- Weights about 3lbs or 1400gs
- Has two hemispheres divided by longitudinal fissure
- Outer layer of the brain, cerebral cortex
- Ridges of tissue are called gyri
- Furrows are called sulci
- Nuclei - aggregation of neurons
- Tracts - bundles of neurons
What are the boundaries of the lobes in the brain viewed as?
- Physical
- Functional
What are the Physical Boundaries of the Lobe?
- Sylvian fissure (lateral sulcus) - the boundary of the temporal lobe
- Central sulcus - divides the frontal lobe from the parietal lobe
What are the Functional Boundaries of the Lobe?
- Precentral gyrus: important for motor control
- Postcentral gyrus: important for touch
- Corpus callosum: a bundle of axons that connects the two cerebral hemispheres
What is the Frontal Lobe?
- Executive Processes
Damage to the frontal lobe can result in:
- Impulsive behavior (arising from difficulty recognizing future consequences of actions)
- Loss of inhibition
- Difficulty planning
- Atypical social skills
- Paralysis
- Difficulty Speaking
What is the Temporal Lobe?
- Hearing, recognition, memory, smell
Damage to the temporal lobe can result in:
- The inability to form new memories (anterograde amnesia)
- Difficulties in auditory perception
- Difficulty with speech comprehension
- Visual agnosia and prosopagnosia (inability to recognize faces)
What is the Parietal Lobe?
- Integration of sensory information from different modalities; spatial
Damage to the parietal lobe can result in:
- Numbness or paraesthesia (pins and needles sensation)
- Difficulty with visually guided movements
- Hemispatial neglect
What is the Occipital Lobe?
- Processing visual information
Damage to the occipital lobe can result in:
- Blindness
- Visual hallucinations
- Inability to see color, motion, or orientation
What is the Cerebral Cortex?
Made up of Grey matter and white matter
What do grey and white matter do?
Gray matter - exterior
- Neuronal cell bodies and dendrites
- No myelin
- Receives and processes information
White matter - below the surface
- Axonal fiber tracts
- Myelin
- Transmits information to other locations
What are the orientations for viewing the brain?
- Sagittal plane - bisects the body into right and left halves
- Coronal plane - divides the body into a front (anterior) and back (posterior) regions
- Horizontal plane - divides the brain into an upper and lower part
What are the directional terms related to the brain?
- Medial - towards the middle
- Lateral - towards the side
- Anterior or rostral - head end or front
- Posterior or caudal - tail end or rear
- Dorsal - top or back
- Ventral - front or underneath
- Proximal - near the center
- Distal - toward the periphery
- Ipsilateral - same side
- Contralateral - opposite side
What are the three subdivisions of the Neural Tube?
The forebrain (prosencephalon) - Telencephalon and Diencephalon
The midbrain (mesencephalon)(brainstem) - Cerebellum and pons
The hindbrain (rhombencephalon)(Brainstem) - Medulla
The brain is bilaterally symmetrical except for what?
Except for the pineal gland, corpus callosum, and pituitary
What are some characteristics of the Cerebral Cortex?
- If unfolded it would occupy 2000 cm^2
- Neurons arranged in six layers
- Cortical layers are unique and differentiated based on
§ Types of neurons
§ Pattern of dendrites or axons - Some structures have allocortex instead, which has three layers or is unlayered
What are the layers of the Cerebral Cortex?
Not Purkinje
Stellate cells
- Dendrites projecting in all directions
- Process sensory information
Pyramidal-shaped cell body in layer III or V
- Apical dendrites extend to the outermost cortex
- Basal dendrites spread horizontally from the cell body
How are the neurons of the cortex organized?
- Neurons in the cortex are organized into cortical columns
- Each column is perpendicular to the cortical layers and serves as a unit to process information
- Cortical regions communicate with one another via tracts of axons
Where is the Basal Ganglia located?
Within the cerebral hemispheres
What is the Basal Ganglia important for?
It is important in motor movement
What does the Basal Ganglia include?
- Caudate nucleus, putamen, and globus pallidus - under the cerebral cortex
- Substantia nigra - the midbrain
What does damage to the Basal Ganglia result in?
- Involuntary muscle movements
- Tremors
- Difficulty initiating movements
- Cognitive impairment
Huntington’s disease and Parkinson’s disease result from damage to the basal ganglia
What does the Limbic System include?
The limbic system includes structures important for learning and memory:
- Amygdala—emotional regulation; perception of odor
- Mammillary bodies, hippocampus, and fornix—contribute to learning and memory
- Septal nuclei—reward and reinforcement in learning
- Cingulate gyrus—attention
- Olfactory bulb—the sense of smell
- Stria terminalis—sex and threat responses; integration of hormonal signals
What gyrus is the motor cortex?
Precentral gyrus
What gyrus is the Somatosensory cortex?
Postcentral gyrus
What are the two main components of the Diencephalon (Forebrain, inner layer)?
(1. ) Thalamus - a cluster of nuclei that relays sensory information (except olfactory)
(2. ) Hypothalamus - contains nuclei with many vital functions, also controls the pituitary
- Important for maintaining homeostasis (by regulating hunger, thirst, temperature) and reproductive behaviors.
- Also controls the pituitary gland (and thus almost all hormone secretion in the body)
What is the Telencephalon?
The outer layer of the Forebrain
What is the midbrain called?
The Mesencephalon
What is the Hindbrain (brain stem) divided into?
Metencephalon
- Cerebellum - Brain structure important for coordination of movement
- Pons - contains the nuclei for several cranial nerves
Myencephalon
-Medulla - contains nuclei that control breathing and heart rate - damage to the medulla usually results in death
What is the Cerebellum?
The little brain
What is the Midbrain divided into?
Tectum
- Superior colliculus (visual processing)
- Inferior colliculus (auditory processing)
Tegmentum
- Substantia nigra (part of basal ganglia)
- Periaqueductal grey (pain control)
- Red nucleus – communicates with motor neurons
- Reticular Formation – sleep & arousal
What is the Cerebellum important for?
Important for coordination of movement (fluidity of movement) and motor learning.
What three layers is the Cerebellum made of?
- Parallel fibers - make up the third, outermost (also called molecular) layer
- Purkinje cell layer - the middle layer; its large cells form a single row
- Granule cell layer - composed of small neurons whose axons form the third layer
What does damage to the Cerebellum affect?
Damage to the cerebellum affects the fluidity of movement and balance
- Affected by alcohol - causes staggering
What three membranes surround the spinal cord and brain?
-Dura mater - tough outermost sheet
-Arachnoid - substance between the dura mater and
pia mater that cushions the brain in cerebrospinal fluid (CSF)
-Pia mater - the delicate innermost layer
What are the cerebral ventricles filled with?
Cerebral spinal fluid
What are the two main functions of CSF
- Acts as a shock absorber
- Provides an exchange medium between blood and brain
The lateral ventricles in each hemisphere extend to what?
Each hemisphere extends into all four lobes and is lined with the choroid plexus, a membrane that produces CSF
CSF flow into the third layer then?
CSF flows into the third ventricle at the midline, then into the fourth ventricle where it exits to circulate over the brain and spinal cord.
What is the Blood-Brain Barrier?
The blood-Brain Barrier refers to the cellular barrier that exists between circulating blood and the brain
Prevents the passage of large molecules and is thought to protect the brain from infections and toxins
Tight junctions between cells make up what?
The capillaries in the brain, as well as astrocyte end-feet, which envelope the capillaries in the brain, are the structures that make up the blood-brain barrier
Neurons die quickly in the absence of what?
In the absence of oxygen and other nutrients. In order to meet the high oxygen and metabolic demands of the brain, there are many blood vessels
What is the Circle of Willis?
The Circle of Willis is an arterial loop that may allow blood to pass by an alternate route to the brain is one of the arteries supplying the brain is blocked
What is an Angiography?
A brain-imaging technique in which a specialized X-ray image of the head is taken shortly after the cerebral blood vessels have been filled with radiopaque dye by means of a catheter.
What is a Computerized Axial Tomography (CAT or CT)?
The X-ray source is moved by steps in an arc around the head, X-rays are absorbed, and after the process is repeated the results create an anatomical map of the brain based on tissue density.
What is Magnetic Resonance Imagng (MRI)?
Uses magnetic energy to generate images that reveal some structural details in the living brain
What is Diffusion Tensor Imaging (DTI)?
A modified form of the MRI in which the diffusion of water in a confined space is exploited to produce images of axonal fiber traces
What is a Fractional Anisotropy (FA)?
The tendency of water to diffuse more readily along the long axis of an enclosed space, such as an axon. FA is the basis of diffusion tensor imaging
What is a DTI Tractography?
Also called fiber tracking. Visualization of the orientation and terminations of white matter tracts in the living brain via diffusion tensor imaging
What is Positron Emissions Tomography (PET)?
A technique for examining brain function by combining tomography with injections of radioactive substances used by the brain.
What is a Functional MRI (fMRI)?
Magnetic resonance imaging detects changes in blood flow and therefore identifies regions of the brain that are particularly active during a given task
What is Optical Imaging?
A method for visualizing brain activity in which near-infrared light passed through the scalp and skull
What is Transcranial Magnetic Stimulation (TMS)?
Localized, non-invasive stimulation of cortical neurons through the application of strong magnetic fields
What is Magnetoencephalography (MEG)?
A non-invasive functional brain-imaging technique that measures the tiny magnetic fields produced by active neurons, in order to identify regions of the brain that are particularly active during a given task.
What has brain imaging allowed an understanding of?
- Lesions - regions of damage within the brain
- Strokes - if blood supply is interrupted due to stroke then the brain tissue dies
What are Gyrus and Sulci?
They are rigged or raised portions of a convoluted brain surface. They are divided by sulci which are a furrow of a convoluted brain surface
What is a Ribosome?
Structures in the cell body where genetic information is translated to produce proteins.
What is the Mitochondrion?
A cellular organelle that provides metabolic energy for the cell’s processes.
What does the Olfactory cranial nerve do?
the nerve that conveys smell
What do the optic cranial nerves do?
The nerve that carries visual information
What does the vestibulocochlear cranial nerve do?
this nerve is concerned with hearing and balance.
What do the oculomotor, trochlear, and abducens cranial nerves do?
They innervate muscles to move the eye.
What does the spinal accessory cranial nerve do?
controls neck muscles
What does the hypoglossal cranial nerve do?
controls the tongue.
What doe the Trigeminal cranial nerve do?
carries facial sensations through some axons and it controls chewing movements through other axons.
What does the facial cranial nerve do?
controls facial muscles and receive some taste sensation
What does the Glossopharyngeal cranial nerve do?
nerves receive additional taste sensations and sensations from the throat and also control the muscles there.
What does the Vagus cranial nerve do?
nerve extends far from the head, innervating the heart, liver, and intestines.
What is the cervical spinal nerve?
Referring to the topmost eight segments of the spinal cord, in the neck region.
What is the thoracic spinal nerve?
Referring to the 12 spinal segments below the cervical (neck) portion of the spinal cord, corresponding with the chest.
What are the lumbar spinal nerves?
Referring to the five spinal segments that make up the upper part of the lower back.
What are the sacral spinal nerves?
Referring to the five spinal segments that make up the lower part of the lower back.
What is the coccygeal spinal nerve?
Referring to the lowest spinal vertebra (also called the tailbone)
What does the Dorsal root of the spinal nerve consist of?
it consists of sensory projections from the body to the spinal cord.
What does the Ventral root of the spinal nerve consist of?
it consists of motor projections from the spinal cord to the muscles.
What is the Sylvian fissure?
Also called the lateral sulcus, it is a deep fissure that demarcates the temporal lobe.
dividing the temporal lobe from other regions.
What is the central sulcus?
A fissure that divides the frontal lobe from the parietal lobe.
What is the Postcentral gyrus?
The strip of the parietal cortex, just behind the central sulcus, receives somatosensory information from the entire body.
What is the Precentral gyrus?
The strip of the frontal cortex, just in front of the central sulcus, is crucial for motor control.
What is the Superior Colliculi?
Paired gray matter structures of the dorsal midbrain that receive visual information and are involved in direction of visual gaze and visual attention to intended stimuli.
What is the Inferior Colliculi?
Paired gray matter structures of the dorsal midbrain that receive auditory information.
What is the pineal gland?
The pineal gland is a small, pine cone-shaped gland of the endocrine system.
A structure of the diencephalon of the brain, the pineal gland produces the hormone melatonin.
Melatonin influences sexual development and sleep-wake cycles.
