Download Anatomy and physiology of male and female

Anatomy and Physiology of
the male and female
Reproductive System
Broad Objective
• To acquire knowledge on anatomy and
physiology of reproductive system and
develop skills and attitudes in order to
manage young peoples’ reproductive
health problems efficiently.
Specific objectives
• Describe anatomy and physiology of the male
and female reproductive system
• Describe the process of fertilization and
implantation
• Describe the functional anatomy of the breast
• Discuss pubertal/secondary characteristics
changes in both male and female adolescents
• Explain developmental anomalies in both
male and females
Anatomy and physiology of male and
female reproductive system
• The normal physiological functioning of the
Reproductive System depends on stimulation
from the brain. The stimulation can be in the
form of hormones or impulses.
• The major parts of the brain involved in the
reproductive system function include:Cortical areas, Cingulate ganglion, Caundate
nuclei, Frontal cortex, Inferior temporal
cortex
• The major glands involved in hormonal
production are Hypothalamus and pituitary
and the gonads
Contd…
• The hormones involved in reproductive
system regulation include gonadotrophins
(Follicle Stimulating Hormone and Leutinizing
Hormone), which are produced by the
pituitary gland.
• The production of the gonadotriphin
hormones is regulated by gonadotrophin
Releasing hormone (GnRH) that produced in
the hypothalamus.
• The gonadotrophins regulate the production
of gonadal hormones.
Contd…
• The gonadal hormones include oestrogen and
progesterone produced by the ovaries and
testosterone produced by the testis.
• The gonadotrophins also regulate the
spermatogenesis and development of the
ovum.
• Hormonal production is regulated by a
negative feedback mechanism.
Anatomy and physiology of male
reproductive system
Lateral view of the male reproductive system
Functions of the male reproductive
system structures
• Penile shaft – is the organ for sexual
intercourse and for passing urine.
• Testis – the male sexual gland. It produces
sperms and testosterone hormone.
• Prostate and seminal vesicle – produces
seminal fluid, which is necessary for sperm
mobility.
• Urethral duct – the canal that ensures
passage of sperms and urine.
Contd…
• Vas deferensReferred to as the spermatic cord or
epididymis. It is a channel for sperms
from the testis to the urethra. Sperm
maturation takes place in this channel.
This is the duct that is severed during
vasectomy.
• Cowper’s gland
Referred to as bulbo-urethral gland. It
produces a fluid, which protects the
sperm
during
transportation
by
neutralizing the acidity in the urethra.
Contd…
• Scrotum
This is a sheath surrounding the
testis. Apart from protecting the testis,
it also regulates testicular temperature
as well as acting as an erogenous zone.
Physiology of male reproductive
system
• Control of male gonads is by hormones
as outlined above.
• FSH works on the seminiferous tubes to
bring about spermatogenesis while
• LH acts on interstitial cells to produce
testosterone.
• Testosterone is responsible for the
secondary sexual characteristics.
Spermatogenesis
• Spermatogenesis begins at puberty and
continues throughout adult life.
• Whereas only few hundred ova are liberated for
fertilization during the life span of a woman,
billions of spermatozoa are formed in the testis
starting from puberty and continuing until old
age.
• Although it takes only one spermatozoon to
fertilize the ovum, there are normally about 20100 million sperms per millilitre of seminal fluid.
• The large number of spermatozoa is necessary
in order to overcome the difficulties, which
they encounter during the journey to the ovum
in the uterine tube.
Contd…
• Only a few thousand are able to reach the
site of fertilization.
The majority are
destroyed by the often-unfavourable chemical
medium found in the vagina, by phagocytosis
and by absorption by the uterine wall.
• The Process of spermatogenesis takes about
70 days and is continuous (after vasectomy
one has to use a condom for about 90 days
since sperms are still present in the vas
deferens for a full sperm cycle)
Factors that can affect
spermatogenesis
• Undescended testis (cryptochirdism)
• Increased scrotal temperature (can be
caused by wearing tight underwear,
scrotal varicose veins)
• Infection of the scrotum and testis e.g.
childhood mumps, epididymorchitis
• Tortion of testis
• Drugs and alcohol
Anatomy and physiology of female
reproductive system
Diagram of the female external genitalia
Female Sexual Anotomy and
Physiology
Functional anatomy of the female
reproductive organs
• Mons pubis – is the pad of fat, which is
covered by hair at the onset of puberty. Normal
pubic hair in the female is distributed in an
inverted triangle at the mons pubis.
• Labia majora – these are two large folds of skin
which cover the external genitalia.
• Labia minora – these are two smaller folds of
skin located beneath the labia majora. As they
join in the upper part they form the hood of the
clitoris. During sexual arousal, they secrete a
thick white substance, which assist in sexual
intercourse.
Contd…
• Clitoris – it is an erectile tissue that corresponds to the
male penis. Its only known role is erotic. It is always
excised during female circumcision (Clitoreidectomy)
Vestibule – is the area between the two labia minora
where the vagina, urethral orifice, and the skenes
glands are located.
• Vagina – the vagina is the canal that connects the
uterus to the external genitalia. It is main functions are
to allow sexual activity and vaginal birth. Its walls are
made of muscle and mucosal layer. The muscles are
arranged in a circular manner, which allows the vaginal
walls to expand and contract. The rugae in the mucosal
layer are important for sensation during sexual
intercourse.
Contd…
• Uterus - This includes the uterine body and the
cervix. The function of the uterus is to
accommodate the pregnancy. The activity of the
ovarian hormones on the uterus leads to the
formation of menstrual blood.
• Cervix –This is the lower part of the uterus that
opens into the vagina. Capacitiation of the sperm
takes place in the cervix. This enables the sperm to
travel up the uterus and to fertilize the ova.
The cervix also produces mucus, which closes the
cervix and prevents germs from entering the
uterus.
The cervical mucus plug thickens when one is
using contraceptives thus enhancing efficacyAt the
onset of labour, the cervical mucus plug mixed with
blood comes out as show.
Contd…
• Cancer of the cervix is the commonest reproductive
tract cancer in females in Kenya.
• Ovaries – these are the female gonads that produce
the ova and the female gonadal hormones
(oestrogen and progesterone).
• Fallopian tubes; –
• They are the ducts in charge of collecting carrying
and feeding the ovum until its arrival in the uterus.
Usually fertilization takes place here.
• They are easily damaged during pelvic infection
leading to infertility.
• Ectopic pregnancy in the tubes may occur as result of
tubal infection and can be life threatening.
• They are severed during bilateral tubal ligation.
Physiology of the female
reproductive system
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Effect / roles of hormones
Ovarian Cycle
Menstrual cycle
Fertilization and implantation
Effect of hormones on the
ovaries
• Control of female gonads is hormonal
and cyclical. Maturation of the
hormonal and gametogenic functions of
the female gonads is initiated during
puberty.
• The cyclic nature of the menstrual cycle
is determined at this time
Effect of hormones on the
ovaries…
• FSH causes maturation of graafian
follicles and also stimulates the theca
cells and granulosa cells to secrete
oestrogen
• LH causes release of the mature ovum
leaving the corpus luteum
• When ovulation does not occur, no
corpus luteum is formed
Effect of hormones on the
ovaries…
• After ovulation, progesterone and
minimal amounts of oestrogen are
produced by the corpus luteum
• During menopause there is atrophy of
the ovaries with resultant cessation of
ovulation and hormonal synthesis
Role of progesterone
hormone
• High levels of progesterone are required for
the maintenance of a pregnancy to term
• It stimulates the development of the breast
alveoli and lobules, and supports lactation
• Progesterone increases body temperature.
This is the basis for using basal body
temperature (BBT) in natural family planning
• A high level of progesterone prevents
ovulation
• Some progesterone preparations are used to
induce labour e.g misoprostol (cytotech)
Role of oestrogen
• Responsible for the development
secondary sexual characteristics
• Leads to the growth of the internal and
external genital organs particularly the
uterus, the vagina and the labia majora
• Responsible for the feminine look and
behaviour (feminising hormone)
• Causes breast enlargement
Role of oestrogen…
• It increases libido
• It has a role in the cyclic changes in the
endometrium that leads to menstruation
• Large doses of oestrogen can lead to blood
clotting problems (thromboembolic disorders,
endometrial cancer, contraception among
others
• Oestrogen and progesterone work together to
maintain the hormonal equilibrium
Ovarian Cycle
• The ovarian cycle has two phases; 1)
Follicular and 2) Luteal
• The follicular phase begins from the
first day of menstruation to the time of
ovulation while the Luteal phase begins
from ovulation until the start of the next
menstruation.
Follicular phase
• From the time of birth, there are many
primordial follicles under the ovarian capsule.
Each contains an immature ovum
• At the start of each cycle, several of these
follicles enlarge and a cavity forms around
the ovum (antrum formation).
• In humans, one of the follicles, (dominant
follicle), in one ovary starts to grow rapidly on
about the sixth day of the menstrual cycle,
while the others regress (atretic follicles).
Follicular phase
• It is not known how one follicle is
singled out for development during this
follicular phase of the menstrual cycle
• When women are given highly purified
human pituitary gonadotrophin
preparations by injection, many follicles
develop simultaneously
Ovulation
• At the 14th – 16th day of the cycle, the
dominant follicle ruptures, and the ovum is
extruded into the abdominal cavity. This is
the process of ovulation
• The ovum is picked up by the fimbrial ends of
the fallopian tubes (oviducts)
• Fertilization normally occurs in the proximal
end of the fallopian tubes. If fertilization does
not occur, the ovum degenerates
Luteal phase
• The follicle that ruptures at the time of
ovulation develops to form the corpus
luteum
• Minor bleeding from the follicle into the
abdominal cavity may cause peritoneal
irritation and fleeting lower abdominal
pain (“mittelschmerz”).
Luteal phase
• If conception occurs the corpus luteum
persist to produce progesterone, which
maintains the pregnancy until the placenta
takes over the progesterone production.
• If there is no pregnancy, the corpus luteum
begins to degenerate about 4 days before the
next menses (day 24 of the cycle) and is
eventually replaced by fibrous tissue, forming
a corpus albicans.
Menstrual Cycle / Uterine
Cycle
• In many cultures a girl is considered as a
woman at menarche. It has been noted that
the age at menarche is decreasing but it is
normally between 10-13 years
• In warmer climates menarche starts at an
earlier age
• Variations in oestrogen and progesterons
levels are responsible for the dramatic
changes in the endometrium throughout the
menstrual cycle
Menstrual Cycle / Uterine
Cycle…
• At the completion of the menstrual period the
endometrium is only 1-2mm millimetres thick
• Under the influence of increasing levels of
oestrogen the endometrium increases in
thickness until by day 12 of the cycle when its
10 to 12 mm thick
• This growth results from an increase in
epithelial and stroma cells of the superficial
layer of endometrium
Menstrual Cycle / Uterine
Cycle…
• This is called the Proliferative Phase and is
characterized by an increase in oestrogen
receptor content and increases in size of the
endometrial glands
• As ovulation approaches, the progesterone
receptor content of the endometrium
increases
• Within two days of ovulation the effect of
rising levels of progesterone becomes
apparent as the endometrium enters the
Secretory Phase of the cycle
Menstrual Cycle / Uterine
Cycle…
• During this phase the mitotic activity in the
epithelium ceases. The glands and blood
vessels become dilated and tortuous
• Glycogen accumulation in the endometrium
reaches its peak level under the combined
influence of oestrogen and progesterone.
This process prepares the endometrium for
embedding of the embryo
• If fertilization does not occur the
progesterone and oestrogen levels decline
resulting in menstruation
Menstrual Phase
• It is characterized by vaginal bleeding
and lasts 2-7 days. It’s the terminal
phase of the cycle and is the period
during which the endometrium is shed
down upto the basal layer together with
blood from the capillaries and the
unfertilised ovum
Schematic presentation of
the menstrual cycle
PROCESS OF FERTILIZATION
AND IMPLANTATION
• Fertilization
– Following ovulation, the egg should be
fertilized within approximately 12-24 hours
– Fertilization occurs in the ampulla of the
fallopian tube, after which a zygote is
formed. The zygote then moves to the
endometrium for implantation
PROCESS OF FERTILIZATION
AND IMPLANTATION…
• Implantation
– Once the Zygote reaches the blastocyst
stage (approximately five to six days after
fertilization), it begins the process of
implantation
– Implantation takes place when the Zygote
attaches or implants at the fundus of the
uterus
THE BREAST
• Anatomy of the breast
– Although the breast is not located in the
pelvic area, it forms part of the female
reproductive system
– During puberty in response to hormonal
stimulation, the female breast begins to
enlarge and mature
Anatomy of the breast…
• The nipple
– The central area through which the milk ducts
open.
• The areola
– The circular dark area around the nipple.
The skin of the areola contains small
elevated nodules or bumps (Montgomery’s
tubercles), beneath which lie the glands of
Montgomery
– These glands are responsible for lubrication
of the nipple and help prevent nipple and
areola cracks and fissures
Anatomy of the breast…
• Mammary glands
-Mammary glands are compound tubuloalveolar glands. They have 15-20 lobes that
radiate out from the nipple separated by
collagenous connective tissue.
-The lobes drain into lactiferous ducts, which
expand to form a lactiferous sinus for milk
storage.
Anatomy of the breast…
• Fat
-80-85 percent of normal breast is fat.
In late pregnancy the fat is replaced by
glandular or milk cells in readiness for
lactation. The fat gives the breast its
shape.
Anatomy of the breast…
• Ligaments of Cooper
-These are bands of fascia that run from the
breast into the sub-cutenious tissues. They
support the breast in its upright position. As
woman grows older, the ligaments weaken
leading to sagging of the breast.
-These ligaments may be distorted by breast
tumours resulting in skin dimpling (lemon
peal appearance).
Figure 6. Structure of the breast
and mammary glands.
Stages of breast development
• Stage I
– Pre-pubertal state, elevation of papilla only
• Stage II
– Breast budding – palpable breast tissue,
areola and nipple begin to enlarge
• Stage III
– Further enlargement of entire breast tissue
Stages of breast development…
• Stage IV
– Secondary mound of areola and papilla
projecting above the breast tissue
• Stage V
– Secondary mound as a rose in stage IV
disappears.
Adult breast with typical
contour
Functions of the breast
• Aesthetic – for cosmetic purposes
• Erogenic – for sensuality
• Lactation – for milk production and
breast feeding
Hormones that regulate
breast function
• Oestrogen – produces duct growth and
general breast enlargement
• Progesterone – stimulates the development of
lobules and alveoli
• Prolactin – causes milk secretion from the
breast after oestrogen and progesterone
priming
• Oxytocin – stimulates the release of milk
when the baby begins to suckle
Adolescent secondary sexual
characteristics in both male and
female
• Adolescent is a period of transition from
childhood into adulthood. It is marked by
dramatic physical, psychological and social
changes
• The onset of puberty, “announces” an
important step on the road to adulthood
• Puberty refers to the physiological changes
that occur in early adolescence (sometimes
beginning in late childhood) which result in
the development of sexual and reproductive
capacity
Adolescent secondary sexual
characteristics in both male and
female
• Physical growth and development
manifest themselves in a growth spurt
during which there are marked changes
in the size and shape of the body
• Differences between boys and girls are
accentuated. For instance, girls develop
feminine characteristics while boys
develop masculine characteristics
Physical and biological
changes in Girls
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Breast enlargement
Genital organs enlargement
Menarche (onset of menstruation)
Growth of body height and weight gain
(adolescent growth spurt)
Hip enlargement
Development of pubic and axiliary hair
Voice changes
Skin problems (acne) may develop
Body shape takes on a characteristic adult
pattern
Physical and biological
changes in Boys
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Voice changes
Spermache (first ejaculation)
Growth of facial, pubic and axiliary hair
Muscular and skeletal growth
Broadening of shoulders
Body shape takes on a characteristic adult
pattern
• Skin problem (acne) may occur
Common problems that occur
during puberty - Girls
• Delayed menarche
• Vaginal discharges
• Menstrual disorders e.g pre-menstrual
syndrome and amenorrhoea
• Breast disorders e.g lumps, pain
• Hirsutism – abnormal hair growth
Common problems that occur
during puberty - Boys
• Wet dreams
• Inflammation of the glans penis and
prepuce (balanopostitis
• Gynaecomastia – abnormal
enlargement of the breast
• Delayed puberty
DEVELOPMENTAL
ANOMALIES
• Male
– Hypospadias –Urethral meatus opening on the
inferior side of the penis
– Epispadias - Urethral meatus opening in the
superior side of the penis
– Perineal or vestibular anus – anus is situated at
the perineum
– Phymosis
- Foreskin is tight at the tip
– Paraphymosis – foreskin is retracted and tight at
the glans penis
– Cryptochidism – undescended testes
– Hermaphrodite – Both male and female genitalia
DEVELOPMENTAL
ANOMALIES…
• Female
– Imperforate hymen
– Mullerian agenesis (absence) and dysgenesis:These are developmental anomalies of the uterus
and the proximal part of the vagina. e.g
bicornuate uterus, absence of uterus and fallopian
tubes
– Vaginal abnormalies – e.g absence of the distal
part of the vagina, agenesis and vaginal septum
among others
– Hermaphrodite – Both male and female genitalia
Female…
– Ambigiuos genitalia – inability to determine
the physical sex at birth
– Perineal or vestibular anus – anus is
situated at the perineum
– Congenital absence of the ovaries.
– Genetic abnormalities like – Tuners
syndrome (45X0), Klinfelters syndrome
(46XXY
– Clitoral hypertrophy