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?