Anatomy and
Physiology
Chapter 2
+ pg. 146
Chapter 3
Anatomy and Physiology
Us and Our Genitals
•
psychology?
•
hang-ups, misunderstanding
•
shame, embarrassment, and guilt
•
public versus private
•
massive diversity
•
pornography
•
homologous tissue/structures
2
Anatomy and Physiology
External Genitalia (Vulva)
Internal Genitalia
•  Mons
Veneris
•  Vagina
•  Labia
Majora
•  Cervix
•  Labia
Minora
•  Uterus
•  Clitoris
•  Vaginal
•  Ovidcuts
Opening
(Fallopian Tubes)
•  Ovaries
•  Vestibule
•  Perineum
•  Urethral
Opening
•  Hymen
3
Female Anatomy and Physiology
External Sex Organs
Mons Veneris (Pubis)
•
•
•
•
fatty tissue that covers the joint
of the pubic bones
acts as a cushion during
intercourse
in front of body, below
abdomen, and above the
clitoris
ample nerves; sensitive to
touch
4
Female Anatomy and Physiology
External Sex Organs
Labia Majora
•
•
•
•
large folds that run downwards
from the mons on the outside of the
vulva
when close together, typically hide
the other parts of the genitals (i.e.,
vaginal opening, the urethra, and
for some females, the labia minora)
– provide protection
outer portion covered with pubic
hair, inner portion hairless
very sensitive to touch
5
Female Anatomy and Physiology
External Sex Organs
Labia Minora
hairless lips that sit inside the labia majora
•  surround the urethral and vaginal opening
•  outer surface merge with the labia majora
and at the top, join with the clitoral hood
•  when sexually aroused, engorge with blood –
become swollen and darker
•  huge variation in size, shape, symmetry, and
colour
•  on average, 2 – 10 cm long, protrude 0.5 – 5
cm
•  also very sensitive to touch
•
6
Female Anatomy and Physiology
External Sex Organs
Clitoris
•
•
•
•
only sex organ whose only known
function is to create pleasure
clitoral shaft → two corpora
cavernosa (spongy tissue) that
becomes engorged with blood and
erect when sexually stimulated
glans → part that is visible, corpus
spongiosum
clitoral hood → covers the exposed
part of the shaft and most of the glans
7
Female Anatomy and Physiology
External Sex Organs
Clitoris
highly innervated – very sensitive to touch
•  shaft mostly hidden in tissue behind where it protrudes
•
•
•
•
•
•
average size: 25mm long, 5mm wide, protrude
3-10mm
no association between size and sensitivity – more
accessible
most sensitive part of the vulva and the vagina
can be uncomfortably sensitive to touch until woman
is aroused (i.e., receptive)
smegma
8
Female Anatomy and Physiology
External Sex Organs
Labia Minora – Labiaplasty
•
•
•
dramatically increasing number of females seeking
plastic surgery for their labia minora (reduction/
symmetry)
other surgeries: vaginal tightening, liposuction of the
mons veneris, hymen reconstruction, unhooding the
clitoris
“designer vagina,” “genital enhancement,” “vaginal
rejuvenation,” “tops and bottoms”
9
Female Anatomy and Physiology
External Sex Organs (FGC/M)
Clitordectomy
parts of Africa and Middle East
•  removal of the clitoris
•  puberty ritual
•  attempt to maintain girls’ chastity
•
Infibulation
practiced mostly in Sudan and Somalia
•  entire removal of clitoris and vulva
•  vaginal opening sutured together; small
passage left for menstruation
•  opened by force when married,
consumation
•
10
11
Female Anatomy and Physiology
External Sex Organs
Vestibule
area inside of the labia minora,
region around urethra and vaginal
opening
•  also very sensitive to touch
•  vulvodynia
•
Urethral Opening
connected to the bladder via the
urethra
•  located above vaginal opening and
below the clitoris
•
12
Female Anatomy and Physiology
External Sex Organs
Urethra
•
•
urinary tract infections: prone to bacterial infections
due to proximity to vagina and anus
cystits – inflammation of the bladder cause by a UTI
13
Female Anatomy and Physiology
14
Female Anatomy and Physiology
External Sex Organs
Vaginal Opening
introitus
•  lies below, and is larger than, the urethral opening
•
hymen – fold of tissue that surrounds or partially covers
the vaginal opening
•  hymens
vary widely
perineum – skin and underlying tissues between vaginal
opening and anus
15
Female Anatomy and Physiology
External Sex Organs
Vaginal Opening – Hymens
Normal
Annular
Hymen
Septate
Hymen
Cribriform
Hymen
Imperforate
Hymen
16
Female Anatomy and Physiology
External Sex Organs
Vaginal Opening
The Hymen and Virginity
•  in
many cultures, intact hymen is considered evidence of
virginity – tearing of hymen during consummation proof of
virginity
•  may
be incomplete in some young females, may tear
during exercise, during sexual exploration, during insertion
of a tampon
•  often
remain intact even after first instance of intercourse
•  virginity
verification; artificial hymens; hymen restoration
•  it
is not possible to confirm that a female is a virgin by
examining her hymen!
17
Female Anatomy and Physiology
External Sex Organs
Underlying Structures
sphincters – muscular rings; vagina and anus
crura – wing-shaped structures that attach the clitoris
to the pubic bone beneath
•  internal
part of the clitoris; corpus cavernosa tissue
18
Female Anatomy and Physiology
External Sex Organs
Underlying Structures
vestibular bulbs – erectile tissue, extending down sides of
vaginal opening
•  engorge
with blood during sexual arousal, swelling the
vulva and lengthening the vagina
•  swelling
contributes to physiological sexual pleasure (for
both partners, if opposite sex couple)
19
Female Anatomy and Physiology
20
Female Anatomy and Physiology
21
Female Anatomy and Physiology
22
Female Anatomy and Physiology
Internal Sex Organs
Vagina
•
•
•
fibromuscular tubular tract
typically 7.5 to 12.5 cm deep at rest; expands in
length and width during sex and childbirth
inner lining, vaginal mucosa; lubrication forms on its
surface during sexual arousal as the tissue of vaginal
wall become engorged with blood
23
Female Anatomy and Physiology
Internal Sex Organs
Lubricants
water-based
+ easy to clean up, safe with all sex toys
– rinse off in water, needs to be re-applied, can contain
glycerin
silicone-based
+ doesn’t rinse off in water, lasts much longer without
reapplication, better for anal sex/play
– messy, can damage silicone sex toys, taste, stain sheets
oil-based
+ lasts forever
– can’t be used with sex toys or condoms, really messy and
difficult to clean up
24
Female Anatomy and Physiology
Internal Sex Organs
Vagina
•
few nerve endings; internal 2/3 insensitive to touch
⇨ sensitive to pressure
•
colonized by a mutually symbiotic flora of
microorganisms (i.e., bacteria) that protect its host from
disease-causing microbes
•
healthy at pH of 4-5 (acidic)
•
discharge
•
self-cleaning; no need to douche or use deodorants
25
Female Anatomy and Physiology
Internal Sex Organs
Pubococcygeus (PC) Muscles
26
Female Anatomy and Physiology
Internal Sex Organs
Kegels
exercise of the pubococcygeus (PC) muscles (muscle
floor of the vagina)
•  runs from pubic bone to tail bone in both sexes
•  initially intended for females who were incontinent after
childbirth
•  enhance sexual experience (for both partners, if
opposite sex)
•
27
Female Anatomy and Physiology
Internal Sex Organs
G Spot
named after Dr. Ernest Grafenberg
•  soft mass of tissues 2.5-5cm from
vaginal entrance
•  intense sensation; vaginal orgasm
•  controversial
•  vagina “highly dynamic structure”
•  clitourethrovaginal (CUV) complex
•
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Female Anatomy and Physiology
Internal Sex Organs
Female Ejaculation
•
intense stimulation of the G Spot, typically, resulting in
the expulsion of fluid from the urethra
•
10-40% of females
•
low-volume versus high volume
•
low volume:
•
•
•
thought to originate from the Skene’s (paraurethral)
glands, which surround lower section of the urethra
similar to secretions from prostate
high volume:
•
secretions from bladder
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Female Anatomy and Physiology
Internal Sex Organs
Female Ejaculation
Study 1 – Schubach (2001)
•  7 females, self-report high volume ejaculators
•  catheter into bladder
•  stimulation to ejaculation
•  fluid primarily from bladder; for some, also from
Skene’s glands
•  composition similar to urine
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Female Anatomy and Physiology
Internal Sex Organs
Female Ejaculation
Study 2 – Salama et al. (2015)
•  7 females, self-report ejaculators
•  ultrasound pre-stimulation, at high arousal, postejaculation
•  stimulation to ejaculation
•  bladder: empty → full → empty
•  composition: urine, some secretions from Skene’s gland
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Female Anatomy and Physiology
Internal Sex Organs
32
Female Anatomy and Physiology
Internal Sex Organs
Cervix
lower end of the uterus
•  os – opening about the size of a pencil
•
cervical cancer
•
risk factors: human papillomavirus (HPV), many sexual
partners, smoking, low SES
•
best defense: regular pap smears and HPV vaccine
•
Gardasil and other vaccines
33
Female Anatomy and Physiology
Internal Sex Organs
Uterus
where the fertilized ovum implants
•  three layers: perimetrium, myometrium, endometrium
•  endometrium richly supplied by blood vessels and
glands
•  formation of lining during menstrual cycle; sheds if no
fertilized ovum present → menstrual bleeding
(shedding)
•
endometriosis
•  endometrial cancer
•
34
Female Anatomy and Physiology
Internal Sex Organs
Oviducts (Fallopian Tubes)
•
passageway for the ova from the ovaries to the uterus
•
tubal ligation – tie off fallopian tubes so ova can’t pass
•
ectopic pregnancy – implantation of the ovum in the
fallopian tubes
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Female Anatomy and Physiology
Internal Sex Organs
Ovaries
•
•
produce oocytes (ova)
•
about 2,000,000 at birth; 400,000 past puberty
•
follicles – hold the oocytes, typically one bursts per month
•
average female will release 400 ripened ova over lifetime
produce hormones
•
•
estrogens (estradiol) – promotes physiological changes
during puberty and control menstrual cycle
progesterone – controls menstrual cycle and stimulates
thickening (proliferation) of the endrometrium (for
pregnancy)
36
Female Anatomy and Physiology
Menstrual Cycle
•  cyclical
changes in physiology controlled by the endocrine
system; typically 28 days
•  menstruation
– shedding of the endometrium; no
fertilization of ovum
•  menarche
– first menstruation
•  amenorrhea
•  3
– absence of menstruation
distinct phases
Ø
Ø
ovarian cycle: follicular phase, ovulation, and the luteal
phase
uterine cycle: menstruation, proliferative phase, and
secretory phase
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Female Anatomy and Physiology
Menstrual Cycle
GnRH – Gonadotropin-Releasing
Hormone
Gonadotropins
FSH – Follicle Stimulating Hormone
»  maturation
»  E
of follicle
by follicle during first half of cycle
LH – Luteinizing Hormone
»  stimulates
»  P/E
ovulation
via the ovary (corpus luteum – P)
Estrogens – estradiol, estrone, estriol
Progesterone
38
Female Anatomy and Physiology
39
Female Anatomy and Physiology
Menstrual Cycle
Menstrual Phase (Follicular Phase)
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•
•
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absence of fertilized ovum leads to
drop in estrogens/progesterone
levels of progesterone drop to the point
at which endometrium lining cannot be
supported; sloughs
typically no longer than a week
use of pads, tampons; more recently
menstrual cups (e.g., the Keeper)
40
Female Anatomy and Physiology
Menstrual Cycle
Proliferative Phase (Follicular Phase)
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•
•
•
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approximately 10 days long
in response to drop in estrogens, pituitary starts to secrete
FSH – signals ripening of 10-20 ova within their follicles
follicles begin production of estrogens → endometrium
thickens
progesterone remains low
surge in GnRH 36 hours before ovulation, increased FSH
stimulates final development of follicle and LH stimulates
ovulation
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Female Anatomy and Physiology
Menstrual Cycle
Ovulation
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•
•
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estrogens peak, progesterone remains low
surge in LH leads to release of a mature ovum from
the ovaries into the fallopian tube(s)
two mature ova fertilized → fraternal twins
one fertilized ovum divides into two zygotes →
identical twins
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Female Anatomy and Physiology
Menstrual Cycle
Secretory (Luteal) Phase
•
corpus luteum – ruptured follicle
•
•
progesterone production by corpus luteum peaks
•
•
acts as an endocrine gland secreting lots of
progesterone and some estrogens
high levels stimulate further thickening of
endometrium and glands of endometrium to secrete
nutrients for fertilized ovum implanted in uterus wall
if no implantation, corpus luteum decomposes and P/E
drop
43
Female Anatomy and Physiology
44
Female Anatomy and Physiology
Menstrual Problems
Dysmenorrhea
pain or discomfort (typically cramps)
primary – no organic origin
secondary – pain secondary to organic problems (e.g.,
endometriosis, pelvic inflammation disease, ovarian
cysts, etc.)
•  cramps (uterine contractions) from prostaglandins
•  fluid retention; in breasts – mastalgia
•  orgasm can relieve menstrual discomfort
•
45
Female Anatomy and Physiology
Menstrual Problems
Premenstrual Symptom (PMS)
•
•
•
•
physiological/psychological symptoms present 4-6
days before period begins
may persist into menstrual phase
can be controlled somewhat by lifestyle (e.g., diet,
exercise)
DSM-5: Premenstrual Dysphoric Disorder
46
Female Anatomy and Physiology
Menstrual Problems
Amenorrhea
•
absence of menstruation; primary sign of infertility
primary – in females who have not menstruated by
age 16-17
secondary – in females who have previously had
normal periods
47
Female Anatomy and Physiology
The Bum
•  anus
– opening
two sphincters:
external – voluntary control
internal – typically involuntary,
although control can be
learned
rectum – outer-most passage
48
Female Anatomy and Physiology
Breasts
secondary sex characteristic
•  15-20 mammary glands per breast
•  filled with fatty tissue – this determines size and shape
•  areola and nipple
•  sensitive to touch
•  large variation in size, shape, position, hair, etc.
•  asymmetrical
•
49
Male Anatomy and Physiology
50
Male Anatomy and Physiology
External Sex Organs
Penis
corpora cavernosa
•  two cylinders of spongy tissue
that run length of penis
•  sinusoids – vascular space
•  engorge with blood when
sexually aroused → stiffen
corpus spongiosum
•  spongy tissue that surrounds
urethra → protects urethra
from being squeezed shut
during erection
•  becomes the glans
51
Male Anatomy and Physiology
External Sex Organs
Penis
frenulum – thin tissue that
connects the underside of
the glans to the shaft
genital end-bulbs – cluster
of tangled nerve endings
corona – ridge around the
edge of the glans
52
Male Anatomy and Physiology
External Sex Organs
Penis
foreskin (prepuce) – loose
skin that covers the glans
smegma – cheese-like
substance that can
collect under the
foreskin
53
Male Anatomy and Physiology
External Sex Organs
Circumcision
surgical removal of the foreskin
•  at birth, adolescence, or adulthood
•
54
Male Anatomy and Physiology
External Sex Organs
Circumcision
55
Male Anatomy and Physiology
External Sex Organs
Circumcision – The Controversy
•
attitudes and culture
•
consent
•
sexual function: mixed evidence
•
HIV/STIs: mixed evidence
•
in areas where few people use protection, may
decrease risk; however, behavioural effects
56
Male Anatomy and Physiology
External Sex Organs
Penis Size
average length: 12.5-15 cm (5-6 inches), erect
average circumference: 11.5-12.5 cm (4.5-5 inches)
57
Male Anatomy and Physiology
External Sex Organs
Penis Size
Katharina Ruppen-Greeff et al. (2015):
according to women, the most important aspects
(rank-ordered):
1.  “general cosmetic appearance”
2.  pubic hair appearance
3.  penile skin
4.  penile girth
5.  glans shape
6.  penile length
7.  scrotum appearance
58
Male Anatomy and Physiology
External Sex Organs
Penis Size Lengthening
•
only effective was to
lengthen penis is surgery
•
release of the fundiform
ligament and the
suspensory ligament
59
Male Anatomy and Physiology
External Sex Organs
Penis Curvature
most penises are curved and
asymmetrical
•  Peyronie’s disease
•
Penile Fracture
•
rupturing of the membrane
that surrounds the corpus
cavernosa
60
Male Anatomy and Physiology
External Sex Organs
Scrotum
•
pouch of loose skin that
holds the testes and
spermatic cord
spermatic cord includes:
vas deferens – passage for
sperm
cremaster muscle – raises
and lowers testes
blood vessels
61
Male Anatomy and Physiology
Internal Sex Organs
Testes
serve two purposes:
1.  produce sperm
2.  produce androgens (i.e., testosterone)
secondary sex characteristics
62
Male Anatomy and Physiology
Internal Sex Organs
Sperm
produced in the seminiferous tubules
through spermatogenesis (64 days)
•  produce 1000/second; 30 billion/year
•  contain 23 chromosomes
•  collected in the epididymis
•
63
Male Anatomy and Physiology
Internal Sex Organs
Passage of the Sperm
•
•
through vas deferens
past the seminal vesicles into
the ejaculatory duct
•
•
•
seminal vesicles secrete fluid
that is part of semen
ejaculatory duct runs through
the prostate gland
past the Cowper’s gland
(i.e., the bulbourethral gland)
64
Male Anatomy and Physiology
Internal Sex Organs
Semen
made up:
•  sperm (1%)
•  seminal fluid from the seminal vesicles (70%)
•  fluid from the prostate (30%)
•  some secretion from the Cowpers’ gland
•  fluids neutralize the acidity of vagina, provide
nourishment for sperm (fructose)
65
Male Anatomy and Physiology
Sexual Function
Erections
•
•
hydraulic pressure created by increased blood flow
into the penis (corpus canvernosa)
elicited in two ways:
1.  reflexive (ejaculation too) response to touch
2.  can also be initiated by the brain: fantasy, visual
stimulation, auditory stimulation – different
pathway higher up in spinal cord
•
brain also has top-down inhibitory control
•
tactile stimulation information sent upwards to brain
66
Male Anatomy and Physiology
Sexual Function
Erections – Autonomic Nervous
System (ANS)
•
ANS divided into the
sympathetic and
parasympathetic branches
•
parasympathetic → erections
•
sympathetic → ejaculation
67
Male Anatomy and Physiology
Sexual Function
Ejaculation
•
•
•
expulsion of semen – with or without orgasm
orgasm – muscle contractions at peak of sexual
arousal associated with tension release and
experienced as very pleasurable
refractory period
68
Male Anatomy and Physiology
Sexual Function
Ejaculation
two stages:
1.  emission stage: contractions of prostate, seminal
vesicles, vas deferens propel semen into urethral
bulb (posterior urethra)
•
urethral bulb stretches; two sphincters at each
end keep semen within
•
ejaculatory inevitability
2.  expulsion stage: semen propelled out the penis by
muscle contractions at its base
69