LEARNING OBJECTIVES
Listed in the Class Notes below=
bold, and blue background
- Read the Class Notes, using the Textbook
illustrations to help understand the concepts. Read the chapter using the
Class Notes as your guide. There are many questions included
to help tie the systems and concepts together into an integrated,
holistic understanding of anatomy and physiology.
- Take the Ch.
19 self test in the online textbook.
DO NOT EMAIL THIS TEST TO YOUR INSTRUCTOR. It is a learning tool
only. These tests will also include
questions that are NOT covered in this course.
- Use any resources on the
Online Textbook,
to integrate your learning.
|
Class Notes
Chapter 19:
Reproductive System
Use the diagrams in the book to enhance
comprehension of these concepts.
The function of the reproductive system is to reproduce
the species, passing to the next generation, the genetics of the parent.
The functional unit of the reproductive system is the
GAMETE, the sex cell.
Sperm - the male sex cell
Ovum, egg - the female sex cell. (Ova is
plural of ovum)
The support functions of the reproductive system are
produce,
transport,
store,
and nourish
the gametes.
To this point, we have focused on HOW each system helps
the organism to maintain homeostasis.
So - How does
'reproduction' help maintain homeostasis?
Define Homeostasis.
This is an 'ECONOMICS' question -
because it is based on resource use.
Define economics.
(NO! it is most certainly NOT 'how money is used'! Look it up.)
The individual that BEST maintains homeostasis, in its
environment, is using its resources (energy and nutrients) the most
efficiently. I.e. that individual is using the LEAST amount of
resources to maintain homeostasis. Ergo, it has energy left over for
'extra' uses - this energy is put into reproduction.
The most energy/resource efficient organism, has more
resources available for reproduction, and therefore produces the most
offspring - passing on to the next generation, more individuals with the
genes for efficient energy/resource use.
Over time, a greater percentage of the population of
individuals has the 'efficient' genes -
remember - the most efficient individual produces
the most offspring -therefore, the next
generation has a larger percentage of individuals with
the most efficient genes.
While the environment remains constant, this process
ensures that the species is able to maintain homeostasis in that
environment - and, indeed, IMPROVES the ability of the species to maintain
homeostasis.
If the environment changes, the genetics of the species
will also change, 'following' the environment. I.e. a different set of
genetics becomes most efficient and produces more offspring - which
changes the genetic composition of the population.
Reproduction maintains the SPECIES' ability to maintain
homeostasis - rather than maintaining the homeostasis of the individual.
| Reproduction passes on, to the next
generation, the ability to most efficiently maintain homeostasis. |
Describe the difference between spermatogenesis and
oogenesis
The gonads, the reproductive organs, produce the
gametes via meiosis.
Gonads - Testes in males and Ovaries in females.
Gametogenesis - production of gametes.
Spermatogenesis - special cells in the testes go
through meiosis and produce sperm,
throughout the lifespan of the male.
Oogenesis - special cells in the ovaries, of the
female FETUS, go through meiosis and
produce
ova - BEFORE birth.
Two gametes (sperm and egg), haploid cells, unite in
fertilization and produce a Zygote.
The zygote is a single cell that is Diploid, because it contains 23
chromosomes from the daddy and
23 chromosomes from the mama; i.e. a 'full set'
of chromosomes.
The zygote undergoes mitosis, producing more
diploid cells, which increase the mass, and
developing into an embryo. The cells of the
embryo continue to go through mitosis, developing
into a fetus. The fetus continues mitosis and
develops eventually into a neo-nate, toddler,
pre-adolescent youth, juvenile (puberty), young adult,
middle-age adult, senior citizen and finally
old adult.
NOTE: at puberty, the individual becomes capable of
REPRODUCTION. It continues to be capable of reproduction through
middle-age. At the end of middle-age, the women go through menopause and
can no longer reproduce.
What are Gonads?
What are the gametes?
What is the functional unit of the reproductive system?
Define:
Gametogenesis
Oogenesis
Spermatogenesis
Gamete
Ovum
Sperm
Zygote
Embryo
Fetus
Neo-nate
When do the cells in the testes go through meiosis and
produce sperm?
When during the lifespan of females, are ova produced?
Define diploid and haploid
With respect to chromosome count there are two types of
cells in humans.
Normal body cells - those cells that make up all the tissues
of the body.
Sex cells - those cells that function ONLY to pass genes to
the offspring via reproduction.
Each normal BODY cell of humans has 23
PAIR of chromosomes.
With 2 chromosomes per pair, normal human body cells
therefore have 46 total chromosomes.
Each SEX cell has 1 chromosome of each pair
of chromosomes - i.e. a TOTAL of 23 chromosomes.
(Other
species have fewer or more)
Diploid - a cell that has both chromosomes of all
the PAIRs of chromosomes.
Normal human body cells are Diploid.
Di - means 2 (two) and Diploid means the cell has 2 of
each pair.
Haploid - an organism that only has 1 chromosome of
each pair.
The sex cells of humans only have 23 chromosomes (1 of each
pair), and are therefore Haploid.
Hap - mean 'half', and sex cells only have 1 of
each pair, i.e. half of the total it could have.
What is a chromosome?
How many pairs of chromosomes do humans have?
How many TOTAL chromosomes do humans have?
Where do we get our chromosomes?
List the essential and accessory organs of the male, give the general function of each
What is the functional organ of the male reproductive
system?
What is the functional UNIT of the male reproductive
system?
Everything else is ‘accessory’.
Male Reproductive System: List organs/genral fxns. Ident/describe external genitalia.
Urologist -one who studies the male reproductive system and urinary
system.
Testes – The male gonads, containing seminiferous tubules in
which specialized cells go through meiosis, producing spermatozoa.
The testes are about 5cm X 3 cm X 2.5 cm. Before birth, the testes are
located in the abdominopelvic cavity, and descend through the inguinal
canal
before birth into the scrotum. Cryptorchidism – "hidden
testes" commonly called Undescended Testicles. Occasionally the
testes remain inside body, i.e. they don’t descend
thru the inguinal canal into the scrotum to cooler
climes. This condition is routinely corrected in the developed
countries (US, Western Europe, etc).
Spermatogenesis (Gametogenesis) takes 9 weeks to go ½ mile through
the seminiferous tubules,
at 1.1 C cooler than body temperature. It all starts
with spermatogonia (define diploid and haploid) (mitosis – diploid
stem cells) which produce spermatocytes which go through meiosis
producing haploid
spermatozoa (23 chromosomes = Haploid).
Parts of a sperm cell:
Head, Acrosomal cap
with Hyaluronidase, an enzyme that breaks through the egg wall, Neck
with mitochondria, and tail (only flagellum in human body).
Name the parts of a sperm cell
Draw and label a sperm cell.
Head
with acrosomal cap
Neck
with mitochondria
Flagellum
What is the function of each part?
Where do you find hyaluronidase?
The word ends in ‘-ase’ – what does this indicate?
What is another name for the flagellum?
What is the function of mitochondria?
Why are there lots of mitochondria in the neck?
Sperm
production requires how much total time?
Why are the testes located OUTSIDE the body cavity?
The
testes are housed in the scrotum.
Scrotum – houses the testes, epithelia lining the testes and scrotum
prevent friction, smooth muscle in the wall of the scrotum in sustained
contraction forms familiar wrinkles. Cremasteric muscle –
(skeletal) can pull testes toward body when temps get cold.
Cremasteric reflex pulls testes up inguinal canal when inner upper
thigh is scratched. Dartos (smooth?) muscle in scrotal wall
pulls testes next to body in cold weather.
Inguinal Canal - an opening in the wall of the abdominopelvic cavity
through which the spermatic cord passes.
Hernia - a 'blow out' – connective tissue tears loose & intestines
fall down and out of their cavity going in wrong direction. When
the intestines (or other structure) protrude through such an opening,
the 'tube' forms a 'loop' and the hernia clamps around it, which stops
the flow through the tube. This can block the intestines, or blood
flow, or whatever normally passes through the tube.
Inguinal -The inguinal canal is a natural opening in
males through which the spermatic
cord normally passes.
Occasionally, the opening will widen and allow the intestines
to protrude.
Incisional - scar tissue from surgery or a wound 'fails'
Hiatal - the natural opening in the diaphragm through which the
esophagus passes
Femoral - the natural opening in the floor of the abdominopelvic
cavity through which
the femoral artery, vein, nerves, etc, pass on
their way to the legs.
Umbilical - the natural opening on the anterior surface of the
abdomen.
Define
hernia and list the types of hernias.
The
spermatic cord is made up of:
Irregular dense connective sheath and
cremasteric muscle that surrounds
the Vas deferens and an artery, vein
and nerve.
The
sperm travel through the seminiferous tubules to the epididymous,
the ductus defrens (aka Vas Deferens), the ejaculatory duct and the urethra to exit the
body.
Epididymous - the sperm spend about 2 weeks maturing here.
Sperm are NOT motile till it gets
fructose, and not fully functional
till exposed to conditions inside
the female reproductive tract.
Capacitation is the condition of a fully functional sperm.
Sperm then pass into the
Vas
deferens (aka Ductus deferens), which transports the sperm to the
Ejaculatory duct – where the Vas joins the seminal vesicle; smooth muscle contracts to
ejaculate sperm into the Urethra.
Urethra-
has 2 functions
in the male:
1. transports sperm (reproductive products) out of the body,
2. transports urine out of the body.
What is the function of the:
epididymous
vas deferens
ejaculatory duct
urethra.
List all the structures in the spermatic cord.
What is an alternate name for the vas deferens?
Describe the accessory organs and their functions
Seminal vesicle – accessory organ, 35%
of semen volume, Fructose in the fluid nourishes sperm,
stimulating sperm motility.
Prostate gland – Accessory organ, 55% of semen volume, the fluid contains bicarbonate
ions which buffer the pH of the urethra (folks in the US eat Amino Acids so acidic urine),
and seminalplasmin.
- surrounds the urethra at the base of the urinary bladder.
- Can enlarge
restricting urethral diameter and urine drainage.
- Prostate Cancer: Kills males. If it has Metastasized to other tissues,
remove prostate
50% of men die within one
year.
Seminalplasmin
– an antibiotic enzyme that MAY help prevent UTI in males.
Proctologist - one who studies the prostate.
Bulbourethral/Cowper’s gland –accessory organ, supplies thick sticky alkaline
fluid to semen that is thought to buffer pH in the vagina.
Semen
– 2-5 ml/ejaculation with about 20-100 million sperm;
seminal fluid is a mix of glandular
secretions with distinctive ionic and nutrient composition; enzymes:
protease dissolves mucous secretions in vagina and seminalplasmin.
‘Clots’
w/in minutes after ejaculation, then reliquefies – unknown fxn. But may fxn
in ‘plugging’
cervical opening, preventing semen from subsequent intercourse
from competing with sperm
from first ejaculation.
Describe the seminal fluid produced by each of these
organs - and give the function of that fluid.
Seminal vesicle
Prostate gland
Bulbourethral gland
What is prostate cancer?
What is another name for the bulbourethral gland?
Describe the characteristics of normal semen.
Describe the external
genitalia and the function
Penis
– tubular organ; skin covering resembles that on scrotum; dorsal blood
vessels and nerves.
3 sections:
Root
– attaches penis to body wall
Body
(shaft) – 3 columns of erectile tissues, 3D maze of vascular channels
incompletely divided
by sheets of connective tissue and smooth muscle.
2 columns of corpora cavernosa – bound to pubis and ischium of the pelvis; central artery.
1 column of corpora spongiosum surrounds the urethra,
and forms the glans penis.
Glans
penis – expanded tip of penis; surrounds external urethral meatus.
Covered by prepuce, (aka foreskin) a loose fold of skin. The surface of the
glans penis is a mucous membrane and contacts the mucous membrane of
the inner surface of the foreskin.
Foreskin- function: physical
and chemical defense for the glans: physical abrasion,
pathogens.
- contains about 50% of the sensory nerve endings of the penis.
- Secretions moisten glans and maintain stratified squamous
epithelium.
Erection- during resting phase little blood flow into erectile
tissues, constricted arterial branches. Arousal – incoming
arteries vasodilate and exiting veins vasoconstrict.
I.e. blood flow into the erectile tissues is
greater than blood flow out.
Flaccid - incoming arteries vasoconstrict and exiting veins
vasodilate.
I.e. blood flow into the erectile tissues is less
than blood flow out.
Hormones: Hypothalamus produces Gonadotropin-releasing Hormone
which stimulates the Anterior Pituitary to secrete FSH and LH.
FSH stimulates spermatogenesis. Spermatogenesis is regulated by a negative
feedback mechanism involving GnRH, FSH, and Inhibin. If FSH becomes
elevated, Inhibin production increases until FSH levels decrease to
normal and Inhibin production decreases and FSH production then accelerates.
LH promotes secretion of testosterone.
Testosterone:
1. Functional
maturation of spermatozoa;
2. maintains accessory organs of male
reproductive tract;
3. determines secondary sexual characteristics;
4.
stimulates metabolic operations throughout the body;
5. influences brain
development: sexual behaviors and sexual drive.
High testosterone levels
inhibit the release of GnRH which causes a reduction in the release of
LH
and subsequent production of testosterone (testosterone levels decrease).
Fertility: male fertility begins to diminish about age 35.
List the essential and accessory organs of the female, give the general function of each
What is the functional organ of the female reproductive
system?
What is the functional UNIT of the female reproductive
system?
Everything else is ‘accessory’.
Female reproductive system :
List organs and general fxns. Identify and describe external genitalia.
Fxn: 1. produce sex hormones and gametes;
2. support developing embryo;
3. nourish newborn infant.
Gynecologist – one who studies the female
reproductive system.
Ovaries
– the female gonads are a flattened oval about 5 cm X 2.5 cm X 0.8 cm.
Briefly describe the life cycle of an oocyte
Oogenesis (meiosis) takes place in the ovary while the
female is still a FETUS - still within the womb - producing about 2
million ova at birth. While it is generally agreed that no more
oogenesis takes place, there is some indication that occasionally a few
more ova will be produced during the reproductive lifespan of the female.
Oogenesis produces primordial follicles (immature
ova surrounded by support cells in a state of suspended animation - 'sleeping') in the ovary.
At puberty, FSH from the anterior pituitary stimulates a primordial
follicle to develop into a
primary follicle, then to a secondary follicle
and eventually into a Tertiary Follicle
aka - Graafian Follicle.
The Graafian Follicle is ready for ovulation - release of the
egg - and subsequent
fertilization by a sperm
There are approximately 400,000 viable primordial
follicles (ova) at puberty. This means that 1.6 million
became NONviable and were reabsorbed by the body. Meanwhile the
female ovulates (releases) 1 ovum per month until menopause.
Menopause is the point in the life span (approximately from age 12 to age
52) at which there are no remaining viable ova.
Define viable and nonviable.
How many eggs are ovulated by the normal woman?
Define Primordial follicle, Primary follicle, Tertiary follicle – AKA Graafian follicle
Draw an ovulated egg.
Note: When the ovum is ovulated, it is surrounded by a ‘shell’
of follicle cells and hyaluronic acid. This shell protects the free
floating egg from bacteria and other things in its environment.
Ovulation – egg release; the oocyte, surrounded by a layer of follicle
cells, floats free within the lumen of the graffian
follicle. The graffian follicle wall ruptures, releasing the egg (and
shell) into the
pelvic cavity. The 'shell' of follicle cells contains Hyaluronic acid w/in zona pellucida.
Hyaluronic acid protects the ovum from bacteria and other threats.
Hyaluronidase is
an enzyme in sperm that breaks down hyaluronic acid. Need lots hyaluronidase
(i.e. lots of sperm) to decomose the hyaluronic acid enough for fertilization. Syngomy occurs when first
sperm reaches the ovum.
The
remnant of the graafian follicle is a layer of follicle cells in the ovary.
This REMNANT develops into the corpus luteum
Corpus
luteum – the empty graafian follicle collapses and follicle cells invade and
multiply to form an endocrine gland that releases the hormone - progesterone.
The corpus luteum starts to disintegrate in about 12
days if fertilization does not occur.
Implantation of a fertilized egg, causes the corpus luteum to remain
functional for 9 to 10 months,
producing progesterone which prevents the secretion of FSH.
No FSH, no graafian follicle and
no subsequent ovulation. This is the basis for using
progesterone for contraception.
Define ovulation, hyaluronidase, hyaluronic acid,
graafian follicle, corpus luteum.
What is the function of each of these?
What does the corpus luteum secrete?
What determines how long the corpus luteum remains
functional?
What happens to the corpus luteum if an egg is fertlized?
Remember: The ovum is ovulated into the
abdominopelvic cavity.
Fimbriae, fingerlike projections of the Uterine tubes, close to the
ovary, gently wave and guide the ovum into the infundibulum of the Uterine
tube, where fertilization normally occurs.
Once inside the uterine tube, cilia and peristaltic contractions move
egg along to uterus (3-4 days from infundibulum to uterus).
Fertilization MUST occur within 12-24 hours of it’s passage and usually
occurs in the infundibulum. Sperm in uterine tube swimming against cilia
and peristalsis.
Ectopic pregnancy: a fertilized
egg that implants somewhere other than in
uterus.
Abdominal ectopic pregnancy - implants within the
abdominopelvic cavity.
Tubal
ectopic pregnancy - implants with the fallopian tube.
The embryo usually does not develop to term, due to a lack of necessary nutrients. It
will last
longer if it implants near artery. May find calcified fetus w/in a woman's
abdomen many
years later.
|
Pelvic
inflammatory disease PID. The fallopian tubes are an open pathway into
the abdominopelvic cavity, therefore, sexually transmitted pathogens may invade
the uterus and uterine tubes and can get into the abdomenopelvic cavity and to other organs.
PID is sometimes called peritonitis.
- IUDs increase the risk.
- Neisseria gonorrhea, chlamydia.
- Normal
vaginal bacteria may also cause problems, especially due to the
appearance
of drug resistant pathogens.
|
Uterine
Tube - aka Fallopian tube, Oviduct. The function is to transport
the ovum to the uterus.
Three parts:
Fimbriae - fingerlike projections that guide the egg into the
infundibulum.
Infundibulum - the funnel shaped opening to the fallopian tube
Fallopian tube - the tube that leads to the uterus
Uterus
(aka Womb) - provides Mechanical and Nutrient support for the developing
embryo and fetus.
The uterine wall consists of:
Endometrium - the external mucous membrane that lines
the lumen of the uterus.
Myometrium - the muscular layer
Epimetrium - the serous membrane, a simple epithelium
with irregular dense connective
tissue that forms a capsule around
the uterus.
Cervix
- the distal end of the uterus that projects into the vaginal cavity and
supports the cervical os, the opening through which sperm must pass in the
journey from the vagina into the uterus.
List the
layers of the Uterus
Describe the endometrium.
Where is the egg when it is ovulated?
Where does fertilization normally occur?
What is an ectopic pregnancy?
Describe the two types of ectopic
pregnancy?
Where is the site
of fertilization which potentially would result in an abdominal ectopic
pregnancy.
How do bacteria enter the abdominopelvic cavity prior to causing
PID?
Vagina
- a muscular tube about 7.5 – 9 cm long (3-3.5 inches), but quite stretchable.
The cervix projects into the vagina, fornix is the space around the cervical
opening.
Bulbospongiosus muscles pass on either side of the vaginal
opening, contractions constrict the opening.
Vaginal walls and lining
contain blood vessels and layers of smooth muscle. Secretions and water
moving across the semipermeable of the epithelial surface and keep the
mucous membrane moist.
The Hymen
is an elastic fold that separates the vagina and the vestibule.
Functions:
1. Passageway
for excretion of menstrual fluids.
2. Receives penis during
intercourse/coitus.
3. Holds and protects sperm prior to their passage into uterus.
4. During
childbirth forms the lower portion of the birth canal.
Resident bacteria supported by the nutrients
found in the mucous produce a pH of 3.5 to 4.5, which restricts the growth
of many pathogenic bacteria.
Vaginitis from fungal, bacterial or parasitic organisms may cause vaginal
infections that affect survival of sperm, reducing fertility.
How does the sperm get through the ‘hyaluronic acid’
shield?
Hint: look at your drawing of a sperm and the acrosomal cap.
What is the function of the fimbriae, fallopian tubes,
uterus, and vagina?
Define endometrium, myometrium, and perimetrium
Describe the structure of the Uterus.
What is endometriosis?
What is the function of the normal resident bacteria in
the vagina.
What is the normal pH of the vagina?
Describe the external
genitalia and the function
The Perineum
is the muscular floor of pelvic region.
The region
around the female reproductive organs is the vulva or pudendum.
The
Labia majora, or outer lips, is skin similar to foreskin in males
overlies adipose tissue and protects
and encloses the labia minora.
Functions to protect the underling mucus membranes from
physical abrasion.
The Labia minora, or inner lips, connects anteriorly and forms the
glans clitoris. The clitoris is erectile tissue that contains
numerous sensory nerve endings. The clitoral prepuce or
clitoral hood is a fold of skin which covers and protects the clitoris.
The Labia minora and clitoris
surround the
vestibule. The vestibule is a common room into which the vagina, urethra and vestibular glands
open. The vestibular
glands, greater and lesser, secrete into the vestibule to maintain
moistness. During arousal the greater vestibular glands, which
resemble the bulbourethral glands in males, discharge mucous into the
vestibule for lubrication.
Approximately 60 to 80% of nerve endings are
located in
the Labia Majora, Labia Minora, vestibule and clitoris. 80 to 90% are found
within labia majora, minora, and the outer 5 cm of the vestibule and vaginal opening (this is why they
say ‘size doesn’t matter’).
The Mons pubis is a layer of adipose tissue beneath
the skin anterior to the pubic symphysis, provides cushioning and protection
during intercourse.
Circumcision:
removal of external genital tissues. Some third world cultures
practice both male and female circumcision as part of their cultural
and religious identity.
Female circumcision is classified in the United States as
female genital
mutilation and called a crime against women, an atrocity,
and is prosecuted
as such.
This procedure most commonly removes
- the labia majora
- the clitioris
- or, both the labia majora and clitoris.
and removes 40 to 80% of the sensory nerve endings.
Female circumcision is usually viewed as chauvinism by
feminists because
the reported goal is to reduce the pleasurable
sensations of intercourse,
making women less likely to 'cheat on the
husband'.
Male
circumcision is removal of the foreskin and 40 to 60% of the
sensory nerve
endings. The US is virtually the only developed
country that practices routine,
nonmedical, male circumcision, with 60 to 90% of males being
circumcised,
depending on age, ethnicity, and parental education.
The procedure costs between $150 to $1500.
Pediatric
Association:
has recommended AGAINST routine, nonmedical
circumcision for more than 25 years.
In the mid to late
1970's the US American Medical Association - Pediatric
Society, responding to criticism that doctors and
hospitals were
performing routine circumcision on male babies as a way
of earning money,
conducted numerous studies and concluded
there is no health related support
for circumcision and have recommended AGAINST routine, nonmedical,
male circumcision.
The recommendation is specifically worded to exclude religious
circumcision.
Based on the official recommendation, public health plans (welfare,
medicare,
etc.) and some private Health Plans (Insurance, HMOs, etc.) classify
circumcision as an elective procedure and do not cover circumcision.
|
How many sensory nerve endings are
removed in male vs. female circumcision.
Compare
and contrast the urethra and functions in males vs. females.
Describe the location of these
structures: Vulva, labia majora, labia minora, glans clitoris, vestibule,
greater vestibular glands.
Mammary
glands. These external genitalia nourish the neonate. They are modified
apocrine sweat glands which secrete milk - Lactation.
Nipple:
ducts of underlying mammary glands connect to lactiferous ducts which
combine to form the
lactiferous sinus which opens onto body surface through
the nipple.
Areola with large sebaceous glands for texture.
Cooper’s
ligaments - suspensory ligaments of dense connective tissue support the
breasts.
Cooper’s droop – ligaments become stretched.
A layer of loose
connective tissue separates the mammary complex from the underlying muscle
and
the two can move relatively independently.
Breast
cancer - 44,000 deaths of women per year; 300 men die of breast cancer
each year.
Describe the menstrual cycle in terms of changes in
hormone levels and the condition of the endometrium
Uterine
cycle:
Menarche is the very first period in the life of the
young woman. It is followed regularly by the
menstrual cycle or monthly period.
Menopause is the cessation of a regular
menstrual cycle and occurs at
45-50 years of age in
most women.
The average cycle is 28
days (21-35 range).
The goal of the uterine cycle is to dispose of the old
inner surface of the uterus and replace it with
new tissues that are more
capable of supporting a newly fertilized egg. This process is repeated
approximately every 28 days.
Look at
the diagram of the Uterine cycle (monthly period) in your book. Notice
that one graphic shows endometrium; another shows the hormones; another
shows ovulation and the corpus luteum, etc. The bottom of the chart is
time, in days.
Three stages:
Menses: period of wholesale destruction
of the superficial layer of the endometrium.
Endometrium
– This is the FUNCTIONAL zone of the uterus.
Remember, the uterus physically
protects and nourishes the implanted embryo.
The endometrium is the inner lining of the uterus into which the
fertilized egg implants. It is comprised of epithelial lining and
underlying connective tissues and capillaries.
Menses is triggered by the decline in progesterone and estrogen levels. Blood vessels
constrict and superficial cells die of O2/nutrient starvation. Weakened
arterial walls rupture and blood flows into the connective tissues. Blood
and degenerating tissues break away and enter the uterine lumen. Sloughing
tissue which continues until entire functional zone has been lost is
menstruation (1-7 days) and usually 35-50 ml of blood is lost.
Proliferative phase: surviving
epithelial cells multiply and spread across the endometrial
surface. Rising
levels of estrogen from next developing ovarian follicle. Endometrium is
several
millimeters thick and endometrial/uterine cells are producing a glycogen rich
mucous. The
Endometrium is again highly vascularized.
Secretory phase: endometrial glands
enlarge and secretion rates increase in preparation for
the arrival of
a developing embryo. Peaks about 12 days after ovulation, and decline leads
to
the end of uterine cycle. A new cycle then begins with menses and the
disintegration of the
functional zone.
Fertility – the six days just prior to
ovulation is the Super fertile period. The best time to have sex to
increase chances of conception is two days before ovulation.
Occasionally, endometrial cells (that are growing) will
grow into the fallopian tubes. These cells are not 'destroyed and
flushed out of the body' during menses, but rather continue to go through
mitosis, producing endometrial cells and tissues. These cells fill
up the lumen of the uterine tube, and may even grow out into the
abdominaopelvic cavity and establish and grow on the mesentaries or the
surface of the organs, etc. This condition is called
Endometriosis.
Define endometrium, myometrium, and perimetrium
Describe the structure of the Uterus.
What is the goal of the menstrual cycle?
What is menses?
Compare the time of ovulation with
the 'peak' in Estrogen and FSH and the level of Progesterone.
What is the corpus luteum?
When is the corpus luteum produced?
What is the function of the corpus luteum?
Describe the corpus luteum with the
levels of progesterone, Estrogen and FSH, as well as with
the Proliferative and Secretory
phases.
What is endometriosis?
What is happening with the blood levels of FSH, LH,
estrogen and progesterone during each phase of the uterine cycle?
At about what day during the menstrual cycle does
ovulation occur?
What is the name of the structure that remains in the
ovary after ovulation of the ovum?
What hormone does it produce?
During which phase of the menstrual cycle does this
occur?
Hormones:
Estrogen: turns girl into female. Helps develop glands, breasts,
endometrium, vagina, female reproductive tract, fat deposits on mons pubis.
Energizes woman, puts salt into bones, inhibits FSH.
LH
– brings about ovulation. Mittle schmertz- when a woman can feel ovulation
occurring.
FSH – stimulates primary follicular
cells to prepare for ovulation.
Inhibin – inhibits FSH
Progesterone: turns female into woman, makes glands functional, speeds
the metabolic rate, responsible for increased basal temperature. Energizes
woman, puts salt into bones.
Sexual intercourse:
Male:
sensory stimulation causes arteriolar dilation in corpora cavernosa and c spongiosum;
bulbourethral secretions moisten the urethra and glans. Rhythmic stimulation
of penile sensory receptors causes emission and ejaculation. Peristaltic
contractions of the ductus deferens begin emission: pushing
fluid/spermatozoa through the ejaculatory ducts and into the urethra. The
seminal vesicles then contract followed by waves of prostate gland
contraction.
Sympathetic nerves contract the urethral sphincter so semen
doesn’t enter the bladder.
Powerful, rhythmic contractions of the ischiocavernosus and bulbospongiosus muscles lead to ejaculation
accompanied by pleasurable sensations – orgasm.
Heart rate and blood
pressure temporarily increase. Blood immediately begins to leave the
erectile tissues and erection subsides, mediated by SNS of ANS fame.
Female:
comparable to male.
Parasympathetic activation leads to engorgement of
erectile tissues of clitoris, labia, and vestibule.
Increased stimulation and
increased secretions from greater vestibular glands and cervix lubricate vaginal
walls.
Clitoral sensitivity increases.
Vaginal walls engorge with blood and
are moistened by fluids from underlying connective tissues. PNS stimulation
cause nipple engorgement.
Rhythmic clitoral and vaginal wall contact, olfactory,
visual, auditory stimulation result in powerful,
rhythmic contractions of the ischiocavernosus and
bulbospongiosus muscles producing sensations
of orgasm.
Name the hormones necessary for the formation of gametes
Review the Endocrine system.
What is FSH and LH?
What is fertilization?
How does the sperm get through the ‘hyaluronic acid’
shield?
Hint: look at your drawing of a sperm and the acrosomal cap.
Define zygote, meiosis, mitosis, gametogenesis,
spermatogenesis, oogenesis.
The suffix '-genesis' means 'creation of'.
Gametogenesis - creation of gametes.
Spermatogenesis - creation of sperm.
Define pathogenic?
What is the function of sexual intercourse?
What are the gametes?
Are they haploid or diploid?
What is ‘fertilization’?
How does fertilization affect the number of
chromosomes in the zygote?
Where do the gametes come from?
How are chromosomes related to gametes?
Where do we get our chromosomes?
Ovum volume is 2K that of sperm.
Why?
The sperm ONLY delivers genes; Ovum has to
nourish it and provide an environment for development.
Sperm are motile
on arrival in the vagina but NOT fully functional until capacitation occurs.
Fertilization normally occurs in the upper 1/3 of
the uterine tube – the infundibulum. Contractions of the uterine
musculature and ciliary movements aid sperm passage.
Of the 200M
sperm in each load of ejaculate, only about 10K make it past the cervix
and fewer than 100 actually reach the oocyte.
Males with a sperm count less than 20M are
usually sterile. Apparently there must be a least 100 sperm thrashing
around, bumping the egg, releasing hyaluronidase to break down the
intercellular cement between the adjacent follicular cells of the corona radiata.
No matter how many sperm enter the gap, the first sperm to contact the oocyte membrane fuses and causes
Oocyte activation.
Oocyte Activation
causes increased metabolism, meiosis is completed, exocytosis of vesicles
releases enzymes that prevent polyspermy (fertilization by additional
sperm).
Male and female pronuclei form and fuse in a process called amphimixis to form
a diploid zygote, spindle fibers form and cleavage begins
- Mitosis.
How does aging affect the
reproductive system?
Menopause:
at about 45-50 years old, women stop menses. The
cause is a shortage/lack of primordial follicles remaining to respond to FSH.
Hormonal balances change and the effects are not well understood.
Osteoporosis and neural effects such as hot flashes, anxiety, depression are
common.
Atherosclerosis and other cardiovascular risks increase.
Male Anticlimacteric:
occurs between 50 and 60 years
of age.
Testosterone level slowly decreases.
FSH and LH levels increase.
Lower
testosterone reduces libido.
Testosterone replacement therapy to improve
libido in older men.
Increased cancer rates
– thought to be due to
decreased functioning of T lymphocytes.
Autoimmune disease rates increase
– body destroys own
tissues as immune system malfunctions.
Vitamins E and C may decrease the physiological
changes of aging.
Describe Contraceptive Techniques
Contraception:
Broadly defined, contraception prevents birth of a baby.
PRE
ejaculation/ovulation:
Block the tube through which the gamete must travel - both male and female:
Vasectomy: Male. Vas deferens
cut and tied/closed off. After ca 1 year, with no
release of
sperm, spermatogenesis stops. Should not stop ejaculation, but may
cause
psychological impotence. Cutting the nerve or lymph vessels may cause
problems like
swollen testes.
Tubal ligation -
Female. The fallopian tubes are cut and tied/closed off. Ovaries
ovulate ova
into the body cavity, but the sperm cannot reach them
95% or so successful -some folks are 'surprised' with a new child.
Chemical
control:
Spermicide - poison that
kills sperm
Pill – oral contraceptive;
keeps the hormones estrogen & progesterone levels high
so FSH
is never activated.
POST
ejaculation/ovulation, but pre-fertilization:
Block the sperm from the egg AFTER ejaculation/ovulation.
Condom - a synthetic or
natural material membrane that completely blocks semen
from
contacting the vagina. There are both male and female condoms.
Use
synthetics to prevent STDs.
95% or so successful.
Diaphragm – vaginal barrier, covers the cervix. Semen comes in
contact with the
vagina,
therefore, diaphragms do not prevent STDs.
Post
fertilization - Prevent implantation, kill embryo/fetus, etc.
IUD- intra uterine device -
basically a foreign object in the uterus, and the uterus
peristaltically tries to expell foreign agent in uterus. Prostaglandins
produced alter
the
chemical composition of the uteral environment lowering the chances of
fertilization.
Abortion - kills the embryo/fetus
Removal of
the gonads:
Castration - removal of the testes. Orchiectomy
Hysterectomy - can be removal of the ovaries, removal of the uterus, or
removal of both
the ovaries and the uterus.
Old
standbys:
Coitus interruptus – withdrawal
of the penis from the vagina prior to ejaculation
Rhythm method - aka Vatican
Roulette, attempts to 'time' intercourse to those
periods of
the menstrual cycle when there is no egg available to be fertilized.
Notoriously unsuccessful as a contraceptive technique.
| What do you call people who use these two techniques
for contraception?
click 'here' for answer. |
Abstinence - no sexual intercourse.
100% successful.
even against STDs!
How does this system interact with the other systems?
Remember – all the systems must work together to maintain
homeostasis.
There are 10 other systems - what are the functions of each and how do
those functions interact with the reproductive system?
How does the reproductive system help maintain
homeostasis?
See the discussion at the beginning of this System.
What is the function of the reproductive system?
The reproductive system passes on, to the next generation, the genes that
are best suited for survival of the species.
The reproductive system maintains the homeostasis of the
species – not the individual.
LAB
Identify and describe the structures that constitute
external genitals in both sexes
Male Reproductive System:
Scrotum
Testes
- Seminiferous tubules
- Epididymis
Ductus Deferens
Accessory Glands
- Seminal Vesicles
- Prostate Gland
- Bulbourethral Glands
Ejaculatory duct
Urethra
Penis
- Root
- Body
- Glans penis
- Prepuce
Spermatozoon Structure
- Head with Acrosomal cap
- Neck
- Flagellum (tail)
Female Reproductive System:
Ovaries
- Oocyte or ovum
- Tertiary follicle or graafian follicle
Uterine tubes
Uterus
Fornix
Vagina
External Genitalia
- Mons pubis
- Labia majora
- Labia minora
- Prepuce of clitoris
- Glans clitoris
- Vestibule
- Urethral opening
- Vaginal entrance
- Hymen
Mammary Glands
- Lactiferous duct
- Nipple
- Areola
|
