VERTEBROBASILAR INSUFFICIENCY
VILLUS
Cervical
vertebrae
Thoracic
vertebrae
Lumbar
vertebrae
Sacrum _
Coccyx _
VERTEBRA
CERVICAL VERTEBRA
THORACIC VERTEBRA
SPINE
LUMBAR VERTEBRA
spine;
12
vertebrae in the thoracic spine;
5 vertebrae in the lumbar spine; 5 fused
vertebrae in the
sacrum;
and 4 fused ver-
tebrae in the
coccyx.
The top 24 vertebrae
are separated by discs of cartilage (see
disc, intervertebral).
Each vertebra has a
hole in the centre through which the
spinal cord
runs,
and processes to
which muscles are attached,
vertebrobasilar
insufficiency
Inter-
mittent episodes of dizziness, double
vision, weakness, and difficulty in speak-
ing caused by reduced blood flow to
parts of the
brain.
It is usually due to
ath-
erosclerosis
of the basilar and vertebral
arteries and other arteries in the base of
the brain. Vertebrobasilar insufficiency
sometimes precedes a
stroke.
vertigo
An illusion that one or one's
surroundings are spinning. Vertigo is
due to a disturbance of the
semicircular
canals
in the inner ear or the nerve
tracts leading from them. Sudden-onset
vertigo is treated with rest and
antihis-
tamine drugs,
which, in some cases, are
also given to prevent recurrent attacks.
vesicle A small
blister,
usually filled with
clear fluid, that forms at a site of skin
damage. The term is also used to refer to
any small sac-like structure in the body.
vestibule A chamber. The vestibule in
the inner ear is a hollow chamber that
connects the 3
semicircular canals.
vestibulitis Inflammation of the nasal
vestibule (the part of the nasal cavity
just inside the nostril), usually as a
result of bacterial infection.
vestibulocochlear nerve The
8
th
cran-
ial nerve.
It consists of 2 branches: the
vestibular nerve (concerned with balance)
and the cochlear nerve (concerned with
hearing). Each vestibulocochlear nerve
(1
on each side) carries sensory im-
pulses from the inner
ear
to the
brain,
which it enters between the pons and
medulla oblongata (in the
brainstem).
A tumour of the cells that surround
the vestibulocochlear nerve (see
acous-
tic neuroma)
may cause loss of balance,
tinnitus,
and
deafness.
Deafness may
also result from damage to the nerve,
which may be due to an infection, such
as
meningitis
or
encephalitis
, or to a
reaction to a drug such as
streptomycin.
viability The capability of independent
survival and development.
villus A minute finger-like projection from
a membranous surface. Millions of villi
are present on the mucous lining of the
small
intestine
. Each intestinal villus con-
tains a small
lymph
vessel and a network
VILLUS
Capillary network
Villus
Mucus-
producing cell
Lymph vessel
Artery
Vein
VILLI OF SMALL INTESTINE
V
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