REPETITIVE STRAIN INJURY (RSI)
RESORPTION, DENTAL
repetitive
strain
injury
(RSI) An
overuse injury
that affects keyboard
workers and musicians, causing weak-
ness and pain in the wrists and fingers.
reproduction, sexual The process of
producing offspring by the fusion of
2
cells from different individuals; this is
achieved in humans by the fusion of
1
sperm
and 1
ovum.
This fusion
(fertiliza-
tion)
is achieved by
sexual intercourse
or
artificial insemination
.
reproductive system, female The fe-
male organs involved in
ovulation
,
sexual
intercourse,
nourishing a fertilized
ovum
until it has developed into a full-grown
fetus,
and
childbirth.
With the exception
of the
vulva
, which protects the opening
of the
vagina
, these organs lie within
the pelvic cavity.
REPRODUCTIVE SYSTEM , FEMALE
Fallopian tube
Bladder
Ovary (
.
Uterus
Vagina
Vulva
Cervix
R
Ova (eggs) are released at monthly
intervals from the
2
ovaries
, which also
secrete
oestrogen hormone
; and
proges-
terone
hormones
that
control
the
reproductive cycle. The ova travel through
the
fallopian tubes
to the
uterus
.
Fertil-
ization
takes place if a
sperm
released
into the vagina during
sexual inter-
course
travels through the
cervix
and
uterus to penetrate an ovum while it is
in the fallopian tube.
reproductive system, male The male
organs involved in the production of
sperm
and in
sexual intercourse.
Sperm
and male sex hormones (
androgen hor-
mones
) are produced in the
testes
, which
are suspended in the
scrotum.
From each
testis, sperm pass into an
epididymis
,
where they mature and are stored. Short-
ly before
ejaculation
, sperm are propelled
REPRODUCTIVE SYSTEM , MALE
Bladder
Seminal vesicle
into a duct called the
vas deferens
,
which carries the sperm to the
seminal
vesicles
behind the
bladder
. These 2
sacs produce
seminal fluid
, which is
added to the sperm to produce
semen
.
Semen travels along 2 ducts to the
ure-
thra.
The ducts pass through the
prostate
gland
, which produces secretions that are
added to the semen. At
orgasm
, semen is
ejaculated from the urethra through the
erect
penis,
which is placed in the woman's
vagina
during sexual intercourse.
resection Surgical removal of all or part
of a diseased or injured organ.
resistance The ability to oppose. In med-
icine, it has several different meanings. A
resistance to the flow of blood is exerted
by the blood vessel walls. Increased
resistance leads to raised blood pres-
sure. In
psychoanalysis
, resistance refers
to the blocking off from consciousness
of repressed memories or emotions.
Resistance may also refer to an ability to
withstand attack from poisons, irritants,
or
microorganisms
. A person's resistance
to infection is called
immunity
. The term
drug resistance refers to the ability of
some microorganisms to withstand attack
from previously effective drug treatments.
resorption, dental Loss of substance
from
teeth.
The loss may be external
(affecting the surface of the root) or
internal (affecting the wall of the pulp
cavity). External resorption is part of
the processs by which
primary teeth
are
lost. Some degree of external resorp-
tion also occurs as part of the aging
process, and may also be due to injury,
486
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