| |
For a complete simple guide on complete
treatment of autoimmune disease by alternatives please read our
e-book
See our services section for
help and contact information.
continued from the Brain Page of
Nervous System
Contents
neurons and Nerves
neurotransmitter
The Brain & Spinal Cord
Cranial Nerves
Peripheral Nervous System
Autonomic Nervous System
Senses: Eye
diagrams, Hearing,
Smell,
Taste, Taste
& Tongue Sensation,
Balance
Memory ,
Memory types, Creation of Memory,
Higher Functions
Altered States
[Top]
Continued from Brain
Continue to next page the cranial nerves
| Cranial Nerve |
CN# |
Brain Region |
Major Functions |
| Terminal§ |
0 |
Near the olfactory |
Reception of pheromone for sex |
| Olfactory |
1 |
Cerebral Cortex |
Smell |
| Optic |
2 |
Limbic
System |
Vision |
| Oculomotor |
3 |
Midbrain |
Eyelid & eyeball movement; pupil dilation |
| Trochlear |
4 |
Pons |
Control downward & lateral eye movement |
| Trigeminal |
5 |
" |
Chewing; sensation of face & mouth |
| Abducens |
6 |
" |
Control lateral eye movement |
| Facial |
7 |
" |
Control most facial expressions;
secretion of tears & saliva; taste; ear sensation |
| Auditory |
8 |
Medulla |
Hearing; balance |
| Glossopharyngeal |
9 |
" |
Taste; swallowing; sensation from tongue,
tonsil, pharynx, carotid blood pressure |
| Vagus |
10 |
" |
Sensory, motor and autonomic functions of
viscera - glands, digestion,
heart rate, breathing rate, aortic blood pressure |
| Spinal Accessory |
11 |
" |
Controls muscles used in head movement |
| Hypoglossal |
12 |
" |
Controls tongue movements |
Table 03 Functions of Cranial Nerves
§ The exact function of the terminal nerve in human is
still under investigation, which is hampered by its small size and
proximity to the olfactory nerve. For mouse and other animals at
least, it is connected to the
vomeronasal organ (vestige in human), which leads to a pathway
for controlling sexual arousal.
| Spinal Nerve(s) |
Innervated Body Part(s) |
Symptom(s) of SCI |
| C1 |
Head and Neck |
Quadriplegia |
| C2-C4 |
Diaphragm |
Breathing problem |
| C5 |
Deltoids, biceps |
No control at wrist or hand |
| C6 |
Wrist extenders |
No hand function |
| C7-T1 |
Triceps, hand |
dexterity problems with hand and fingers |
| T2-T8 |
Chest muscles |
Paraplegia, poor trunk control |
| T9-T12 |
Abdominal muscles |
Paraplegia |
| Lumbar and Sacral |
Leg muscles, bowel, bladder, sexual organs |
Decreasing control of hip flexors and legs, dysfunction
of bowel, bladder, and sex |
Table 04 Symptom(s) of Spinal Cord Injury
Note: Other effects of SCI may include low blood pressure, inability
to regulate blood pressure effectively, reduced control of body
temperature, inability to sweat below the level of injury, and
chronic pain.
[Top]
 |
One division of the autonomic nervous
system, called the sympathetic
nervous system, dominates in times of stress. It controls
the "fight or flight" reaction, increasing blood pressure,
heart rate, breathing rate, and blood flow to the muscles.
Another division, called the parasympathetic nervous system,
has the opposite effect. It conserves energy by slowing the
heartbeat and breathing rate, and by promoting digestion and
elimination (of waste). Most glands, smooth muscles, and
cardiac muscles constantly get inputs from both the
sympathetic and parasympathetic systems. The CNS controls
the activity by varying the ratio of the signals. Depending
on which motor neurons are selected by the CNS, the net
effect of the arriving signals |
|
|
will either stimulate or inhibit the organ.
Figure 07 shows the various organs and actions, which are
related to the two different divisions.
|
Motor fibers that govern involuntary responses, do not lead directly
to the organs they innervate. Instead, they make their trips in two
stages. The first set of fibers leads from the CNS to ganglia (which
are collections of nerve cell bodies) that lie outside
 |
the CNS (the preganglionic fibers). At the
ganglia the fibers form synaptic junctions with the
dendrites of as many as twenty different cell bodies. The
axons of these cell bodies form a second set of fibers, the
postganglionic fibers. It is these postganglionic fibers
that lead to the organs.
The chief ganglia involved in the autonomic nervous system
form two lines running down either side of the spinal
column. They are outside the bony vertebrae. These two lines
of ganglia outside the column resemble a pair of long beaded
cords. At the lower end, the two cords join and finish in a
single central stretch. These lines of ganglia are sometimes
called the sympathetic trunks (used by the sympathetic
nervous system). Not all ganglia are located in the
sympathetic trunks. Some are not; and it is possible for a
preganglionic fiber to go right through, making no synaptic
junction there at all, joining instead with ganglia located
in front of the vertebrae. For the parasympathetic nervous
system, some of the ganglia separating the preganglionic
fibers from the postganglionic fibers are actually located
within the organ the nerve is servicing. In that case, the
preganglionic fiber runs almost the full length of the total
track, whereas the postganglionic fiber is at most just a
few millimeters long.
The splanchnic nerves, which originate from some of the
thoracic nerves, have their preganglionic fibers ending in a
mass of ganglia lying just behind the stomach. It represents
the largest mass of nerve cells that is not within the CNS
and is sometimes called the "abdominal brain". It is a vital
spot to be protected during boxing. |
|
|
Figure 08 is the front view of a more
detailed ANS anatomy.
|
[Top]
 |
 |
Senses organs receive external and internal
stimuli; therefore, they are called receptors. Each type of
receptor is sensitive to only one type of stimulus as listed
Table 05, while Figure 09 shows many types of receptors.
When a receptor is stimulated, it generated nerve impulses
that are transmitted to the spinal cord and/or the brain,
but we are conscious of a sensation only if the impulses
reach the cerebrum. |
|
|
|
|
| Receptor |
Type |
Sense |
Stimulus |
| General |
|
|
|
| Ruffini's endings, Krause end bulbs |
Radioreceptor |
Hot-cold |
Heat flow |
| Merkel's and Meissner's endings |
Mechanoreceptor |
Touch |
Mechanical displacement of tissue |
| Pacinian corpuscles |
Mechanoreceptor |
Pressure |
Mechanical displacement of tissue |
| Free nerve endings |
Chemoreceptor |
Pain |
Tissue damage |
| Proprioceptors |
Mechanoreceptor |
Limb placement |
Mechanical displacement |
| Special |
|
|
|
| Eye |
Radioreceptor |
Sight |
Light |
| Ear |
Mechanoreceptor |
Hearing |
Sound wave |
| Olfactory cells |
Chemoreceptor |
Smell |
Chemicals |
| Taste buds |
Chemoreceptor |
Taste |
Chemicals |
Table 05 Receptors
The general receptors distribute all over the skin. They are usually
grouped together as sensation. The special receptors locate only at
certain part of the body in the head. Altogether, they are referred
to as the five senses. The followings present a further break down
into components, and functions.
continue to Eye diagrams |
World Wide Consultation by Internet
DHEA levels and
cognitive functions
SESAME SEED OIL
Facial cleaner
Quran
page |
