Module 6: Nervous System
limbic system
-"emotional brain" that includes parts of the cerebrum and the diencephalon. -system has extensive connections to both lower and higher brain regions, responsible for the coordination of, integration of, and response to a variety of environmental stimuli
epidural space
-Between vertebral canal and outermost membrane -Contains cushion of fat and connective tissue
neuroglia
-Cells that support, nourish, and maintain neurons. -Don't conduct impulses
cerebellum
-Center of learned, coordinated movement -responsible for smooth coordination of skeletal muscle movement and for balance and posture. -receives input from proprioceptors, as well as visual and equilibrium pathways.
nerve tract
-Each white matter column contains one or more of these. -A bundle of myelinated axons having a common origin or destination and carrying similar information.
hypothalamus
-Plays a very large role in the regulation of homeostasis -has temperature control centres, thirst/satiety centres, ANS control, and emotions
cranial dura mater
-Splits into two layers, with the outer layer closely adherent to the skull. (no layer of epidural fat and connective tissue) -Cerebral spinal fluid and most of the veins from the brain drain into the superior sagittal sinus that lies between the two layers of this
cranial nerves
-carry signals to periphery and back to brain -there are 12 -part of the peripheral nervous system -numbered in the order that they emerge from the brain
axon
-conducts nerve impulses toward another neuron, muscle cell, or gland cell -on other side of cell body, long extension
subarachnoid space
-filled with cerebrospinal fluid -contains largest blood vessels supplying the brain
Wernicke's area
-in the left temporal and parietal lobes -interprets the meaning of speech and written words
pia mater
-inner layer of meninges -contains numerous blood vessels -very delicate
somatosensory association area
-lies just posterior to the primary somatosensory area - integrates and interprets somatic sensations such as shape, size, and texture.
auditory association area
-lies posterior to the primary auditory cortex -permits interpretations of sound as speech or song, or a screech.
sensory areas
-located behind the central sulcus -these regions receive the majority of sensory input from the sensory receptors in the peripheral nervous system.
primary visual area
-located in the occipital lobe -receives and perceives visual information
primary motor area
-located in the pre-central gyrus -controls the voluntary movement of skeletal muscles
primary auditory area
-located in the superior margin of the temporal lobe adjacent to the lateral sulcus -responsible for the reception and perception of sound (e.g., pitch, volume, location).
primary olfactory area
-located on the medial aspect of the temporal lobe -responsible for the perception of smell
primary somatosensory area
-located posterior to the central sulcus in the postcentral gyrus of the parietal lobe -responsible for the perception of touch, pain, itching, tickle, and temperature -detects input from proprioceptors, which perceive joint and muscle position
cerebral hemispheres
-make up about 83% of total brain mass. -have folded areas known as gyri and grooves known as sulci -each part has four lobes named after the skull bones that cover them: the frontal, parietal, temporal and occipital lobes.
arachnoid mater
-middle layer of meninges -loose arrangement of collagen and elastic fibers
dura mater
-outer layer of meninges -dense irregular connective tissue -extends to second sacral vertebrae
primary gustatory area
-receives and perceives taste -located in the post central gyrus near the somatosensory area
dendrites
-receiving/input parts of neuron -membranous branch-like processes that emerge from the cell body
cerebrum
-responsible for all of the higher order cognitive functions -consists of left and right cerebral hemispheres -coordinates sensory and motor activity and is the site of "higher learning" or "intelligence": centers responsible for memory, emotion, and language
motor areas
-responsible for initiating movements -carry impulses out from the cerebrum to the periphery -located primarily in the frontal lobe.
ganglia
-small swellings on either sides of spinal cord -collection of cell bodies of neurons in the PNS
visual association area
-surrounds the primary visual cortex -uses past visual experiences to interpret visual stimuli
functions of hypothalamus
1. control of ANS 2. production of hormones and control of the pituitary gland 3. regulation of emotional and behavioral patterns 4. regulation of thirst and appetite 5. regulation of heat balance 6. regulation of circadian rhythms
Schwann cells and oligodendrocytes
2 neuroglia cells that generate the myelin sheath:
meninges
3 connective tissue layers that surround the spinal cord are called:
sensory, integrative, motor
3 functions of nervous system
sensory, motor, association
3 general functional areas of the cerebral cortex
dura mater, arachnoid mater, pia mater
3 layers of meninges:
thalamus, hypothalamus, pineal gland
3 parts of diencephalon:
somatic, autonomic, and enteric nervous system
3 subdivisions of PNS:
action potential
Allows nervous system to provide communication between an organism and its environment, and between internal regions of an organism
potassium, sodium
At resting potential, the inside of the neuron has lots of ---, while the outside has lots of ---
synaptic transmission
At synapses, neurons communicate with other neurons or effectors by a series of events known as:
sodium, potassium
At the end of repolarization, the inside of the neuron has lots of ---, and the outside of the neuron has lots of ---
resting potential
At this state, the cell is negatively charged compared to the outside
midbrain, pons, medulla oblongata
Brain stem is divided into:
nerve
Bundle of axons (ssometimes dendrites) and connective tissue and blood vessels. Lie outside brain and spinal cord
sensory component
Carries info to CNS
brain and spinal cord
Central nervous system consists of:
cranial meninges
Consist of: dura mater, arachnoid mater, and pia mater
bipolar neurons
Contain 1 main dendrite and 1 axon. found in retina, inner ear, and olfactory area of brain
unipolar neurons
Contain dendrites and 1 axon fused together to form a continuous process emerging from the cell body
multipolar neurons
Contain several dendrites and one axon. Found in brain and spinal cord
Pons
Contains respiratory centres of brain stem
Broca's speech area
Control and direction of the muscle of speech is in the ---which is located close to the lateral cerebral sulcus, usually only in the left hemisphere.
medulla oblongata
Division of brain stem: -Merges right into the spinal cord -consists of tracts running from the spinal cord and several nuclei, regions of gray matter within the CNS -Has cardiovascular and respiratory centres and autonomic reflexes which are non-vital
into, out of
During action potential, sodium flows --- the cell and potassium flows --- the cell
stimulus
During spinal reflex: A stretch receptor in the muscle responds to the initial ---.
dendrites, cell body, axon
During spinal reflex: The action potential travels from the --- to the --- and then along the --- of the motor neuron. The myelinated axon travels through a ventral column and out through the ventral root of the spinal nerve.
integrating center
During spinal reflex: The gray matter of the spinal cord acts as an ---, determining and initiating the appropriate regulatory response to the initial stimulus.
cell body, spinal cord
During spinal reflex: The stretch receptor triggers an action potential, which is carried along the dendrites of the sensory neuron to the --- (located in the dorsal root ganglion of the spinal nerve) and then along the axon into the gray matter of the ---. Axon branches also travel up the spinal cord to the brain, triggering conscious awareness of the stimulus.
myelin sheath
Each Schwann cell wraps around an axon, forming a protective membrane called:
frontal, parietal, temporal, occipital
Each part of cerebral hemispheres has four lobes named after the skull bones that cover them:
dendrites, cell body, axon, synaptic end bulbs
Electrical impulses start at --- and travel towards the ---, then out along the --- to the ---
spinal cord
Enclosed by vertebral column, contains 100 million neurons, connects to brain, extends from medulla oblongata to upper border of second lumbar vertebra
increases, slows
For example, sympathetic stimulation --- heart rate while parasympathetic --- stimulation heart rate.
unmyelinated
In --- processes, there is a continuous pattern of action potential flow
myelinated
In a --- process, the action potential jumps from one node to the next
repolarization
Inside of cell becomes more negatively charged
depolarization
Inside of cell becomes more positively charged
saltatory conduction
Jumping of action potential from one node to the next in a myelinate process is called:
cell body
Major cell metabolism and protein synthesis is carried out here
cerebrum, diencephalon, cerebellum, brain stem
Major parts of brain:
sympathetic and parasympathetic division
Motor component of autonomic nervous system has 2 subdivisions:
motor (efferent) nerves, effectors
Motor function is carried out by --- that carry messages from the CNS to appropriate peripheral --- such as muscles or glands
vagus nerve
Nerve 10 -brings in sensory input from a wide variety of areas including most of the organs in thoracic and abdominal cavities. -The motor portion is important in the regulation of heart rate, as well as in parasympathetic responses of the airways and intestinal tract
optic nerve
Nerve 2 are entirely sensory
olfactory nerve
Nerves 1 brings in impulses from nose for sense of smell
intercostal nerves
Nerves T1-T12 give rise to the:
central and peripheral
Nervous system is divided into:
neurons and neuroglia
Nervous tissue consists of 2 types of cells:
synaptic vesicles
Neurotransmitters are stored in:
nervous tissue outside CNS
Peripheral nervous system consists of:
myelinated
Portions of an axon that contain ion channels. Only place where ion movements occur that produce action potential
thalamus
Receives the ascending nerves and directs the nerve to the corresponding cerebral area. All outgoing nerves form the cerebellum route through the thalamus to become the descending nerve
pupillary, lens accommodation, movement of head and neck
Reflexes of midbrain:
action potential
Region of depolarization and repolarization that moves along the membrane
dorsal horns
Region of gray matter: Contain the cell bodies of interneurons and the axon terminals of incoming somatic and autonomic sensory neurons.
ventral horns
Region of gray matter: Contain the cell bodies of somatic motor neurons
lateral horns
Region of gray matter: contain the cell bodies of autonomic motor neurons, and are found only in the thoracic, upper lumbar, and sacral areas of the cord.
motor function
Response carried out from the central nervous system
autonomic nervous system
Sensory component: carries info to CNS form autonomic sensory receptors in viscera Motor component: consists of involuntarily neurons that carry messages to smooth muscle, glands, and cardiac muscle
somatic nervous system
Sensory component: consists of sensory neurons that carry messages from receptors for special senses Motor component:: voluntary and consists of motor neurons that innervate skeletal muscles
enteric nervous system
Sensory neurons and receptors: detect physical and chemical changes related to digestion. This info gets conveyed to CNS and enteric motor neurons Motor component: send commands to glands, smooth muscle, and secretory cells of GI tract
bony canal, meninges, fluid cushion
Spinal cord is protected by:
parasympathetic division
Stimulation of this part of the autonomic nervous system produces "rest and digest" responses, generally increasing digestive activity and reducing activities.
coughing, hiccupping, sneezing, vomiting
The autonomic reflexes of the medulla oblongata are non-vital and include:
presynaptic neuron
The axon preceding the synaptic cleft is called the:
drsal root, dorsal horn
The axons of sensory neurons enter through the --- into the --- of the gray matter. .
blood-brain barrier
The capillaries in the brain are different from any others in that they maintain a very tight barrier known as the ---. This prevents passage of harmful substances and pathogens from the blood into the brain tissue.
heart rate, force of contraction of the heart, and blood vessel diameter
The cardiovascular center of the medulla oblongata controls: Other centers in the medulla control the reflexes of coughing, hiccupping, sneezing, and vomiting.
ventral horn, ventral root
The cell bodies of motor neurons are located in the ---, and the motor axons exit in the --- of the spinal nerve
dorsal root
The cell bodies of the sensory neurons are in the:
corpus callosum
The cerebral hemispheres are connected by a large band of white matter called the:
cerebral cortex, white matter, basal ganglia
The cerebrum has an outer layer of gray matter, called the ---, an internal region of ---, and three pairs of nuclei called the --- buried in the white matter.
ventral, lateral, and dorsal horns
The gray matter is subdivided on both sides into regions called:
inspiratory area and an expiratory area, breathing
The respiratory center of the medulla oblongata consists of: ---, both of which function in the control of ---
maintaining consciousness
The sensory portion of the reticular formation is responsible for ---
dorsal, lateral, and ventral columns
The white matter, consisting of myelinated axons, is organized into:
cervical, thoracic, lumbar, sacral, coccygeal
There are 31 pairs of spinal nerves, all named for their point of exit from the spinal cord:
the left and right lateral ventricles, third ventricle, and fourth ventricle
There are four interconnected chambers or ventricles in the brain:
acetylcholine
This neurotransmitter is found associated with the parasympathetic neurons, as well as some in the sympathetic system
norepinephrine (noradrenaline)
This neurotransmitter is found in sympathetic neurons, but not in parasympathetic neurons.
diffusion, digestion, reuptake
To complete the process of synaptic transmission, the neurotransmitter must be removed from the cleft. This is accomplished in one of three ways: --- away from the cleft, --- with specific enzymes, or --- into the presynaptic neuron.
refractory period
To return to resting potential, actibe transport and Na/K ATPase pump come into play to pump Na out of the cell and bring K into the cell. This process is called the:
spinal reflex
When a integration takes place in the spinal cord gray matter, the reflex is called a:
action potential
When a neuron synapses with a muscle or gland, the neurotransmitter binds to the gland or muscle cell and triggers an --- in that cell, which stimulates the secretion by a gland or contraction of a muscle
synaptic cleft, postsynaptic neuron
When an impulse reaches the synaptic end bulb of a presynamptic neuron, the electrical stimulus is converted to a chemical message in the --- and then into a second electrical stimulus in the ---
neurotransmitter
When the impulse reaches the synaptic end bulb of the presynaptic neuron, it causes an influx of calcium ions into the neuron. This influx, in turn, triggers the release of a chemical called a --- into the synaptic cleft
sodium channels open
Which of the following occurs during the depolarization phase of the action potential?
plexus
With the exception of nerves T2-T12, all the nerves from a given region join one another lateral to the spinal cord to form a complicated network called a:
cerebrospinal fluid
a clear, colorless fluid that serves as a cushion, and also carries oxygen, glucose, and other nutrients from the blood to the cells of the brain and spinal cord.
reflex
a fast, involuntary series of actions that occur in response to a stimulus
choroid plexus
a group of specialized capillaries in the walls of the ventricles that produces cerebrospinal fluid (CSF)
melatonin
a hormone that induces sleep and is involved in setting the body's biological clock
reticular formation
a net-like arrangement of small clusters of cell bodies and myelinated axons that runs through the central core of the brainstem.
dendrites, axon, cell body
a neuron consists of 3 parts:
association areas
are concerned with integration of senses, movement, emotions, and others.
depolarized
at the end of action potential, the cell is:
synaptic end bulbs
axon terminals have bulb-like extensions called:
axon terminals
axon terminates in:
motor component
carries electrical commands out from the CNS to the effectors
postganglionic neuron
carries the impulse from the ganglion to the gland or smooth muscle
motor tracts
carry information down the spinal cord.
sensory tracts
carry information to the brain
sensory (afferent) nerves
carry sensory info to central nervous system
neuron
cell that carries nerve impulses
gray matter
composed of unmyelinated tissue, contains cell bodies and axon terminals, is in the center region of the spinal cord
stretch receptor
consists of specialized dendrites of a sensory neuron.
dura, arachnoid, and pia mater
cranial meninges consists of these three extensions of the spinal cord coverings:
sensory receptors
detect signals from periphery (pain, smell, light, sound, pressure, etc.)
midbrain
division of brain stem: -connects the pons to the diencephalon and consists mainly of ascending and descending tracts. -associated with several reflexes: the pupillary reflex, (pupillary size adjustment in response to light), the lens accommodation reflex, and reflexes involving movement of the head and neck in response to visual stimuli.
preganglionic neuron
first autonomic motor neuron in an autonomic pathway, with its cell body and dendrites in the brain or spinal cord and its myelinated axon ending at an autonomic ganglion, where it synapses with a postganglionic neuron
gyri
folded areas of cerebral hemispheres
oligodendrocytes
generate myelin sheath in CNS
sulci
grooves of cerebral hemispheres
medulla oblongata
he cardiovascular control center, which controls the rate and force of the heart contraction and the diameter of blood vessels, is located in the:
12
how many cranial nerves are there?
myelin sheath
increase speed of nerve conduction along axon
interneurons
integrative functions of nervous system are carried out by short:
white matter
made up of myelinated axons, forms the outer region.of spinal cord
synaptic cleft
microscopic gap at the end of synaptic end bulbs that separates then from next axon.
Schwann cells
neuroglial cell of PNS that forms myelin sheath and neurolemma around axon
junction
neuron and non-neuron interaction site is called:
synapse
neuron-to-neuron interaction site is called:
nodes of Ranvier
non myelinated gaps between Schwann cells that form the myelin sheath and neurolemma are called:
spinal nerves
paths of communication between spinal cord and specific regions of the body
pineal gland
pea-sized gland that secretes melatonin
cauda equine
spinal nerves end at superior border of L2, and the roots of the lumbar and sacral nerves angle down the vertebral cavity to make up the:
sympathetic division
stimulation of this part of the autonomic nervous system produces "fight or flight" responses, such as responses associated with excitement, energy, exercise, and embarrassment
neurotransmitters
synthesized in the cell bodies of neurons and are transported along the axon to be stored in the axon terminals
20%, glucose
the brain requires ---of the body's oxygen supply and a constant supply of ---
post synaptic neuron
the dendrites following the synaptic cleft belong to the:
regulation of muscle tone
the motor portion of the reticular formation is responsible for the ---
cranial nerve, sacral
the parasympathetic preganglionic neuron outflow originates in the --- nuclei and the --- regions of the cord
thoracolumbar
the sympathetic preganglionic neuron impulses originate in the central, --- regions of the spinal cord
white
what colour is myelin?
