Transcript The reproductive system

The reproductive
system and
development
Ch. 31,32,33
Warm up
• Think about what you already know
about the reproductive system and
write it on your card.
Introduction
• Purpose: Carry on the human
species
• Made of a Series of glands and
tubes
• Produce and nurture sex cells
• Transport sex cells to site of
fertilization
Organs of the male reproductive
• Designed to produce sperm and transport
sperm to site of fertilization
• Sex organs - gonads
• Testes – ovoid structures that produce
sperm
– Suspended by spermatic cord in scrotum
– Structure of testes
• 250 lobules per teste, separated by connective
tissue
• Each lobule holds 1-4 highly coiled
seminiferous tubules
• Seminiferous tubules lined with epithelium –
makes sperm
• Sperm stays in seminiferous tubule for 1-3
weeks.
– Formation of sperm
– Spermatogenesis
Spermatgenesis
sperm
• Sperm cell – head contains haploid
nucleus, mid-piece containing
mitochondria, tail – flagellum
• Tip of head – acrosome – contains
enzyme that erode tissues
surrounding female egg cell
Male internal accessory organs
• Epididymis – tightly coiled tube near testis, leads to
vas deferens – where sperm mature
• Vas deferens – muscular tube leads from epididymis
into body cavity
• Seminal vesicle-saclike structure near base of
bladder – secretes alkaline fluid that enhances sperm
mobility and neutralizes female reproductive tract
acidity
• Cowper’s gland – secretes fructose sugar to nourish
sperm
• Prostate gland-chestnut shaped structure
surrounding urethra – secretes thin fluid-neutralizes
acidity
• Bulbourethral glands – secretes mucus for lubrication
• Semen – combination of sperm cells (120 million per
milliliter), secretions from accessory glands
Male external reproductive
organs
• Scrotum-pouch of skin and tissue
that holds testes suspended from
lower abdomen – keeps testes
cooler
• Penis – specialized erectile tissue
designed to convey urine and semen
to outside.
Hormonal control of male
reproductive function
• Hypothalamic and pituitary hormones
– Gonadotropin releasing hormone –
triggers production of other hormones
– Luteinizing hormone – promotes
development of interstitial cells in testes
which secrete male hormone testosterone
– Testosterone is responsible for secondary
sex characteristics.
– Follicle stimulating hormone – stimulates
supporting cells of seminiferous tubules
for spermatogenesis
Reflection
1. What is the purpose of the
reproductive system?
2. Describe sperm.
3. How does sperm swim?
4. What controls the reproductive
system?
Warm up – 4x6 Check wall for
missing work
1. In the male reproductive system, the
essential organ is called____
2. List the accessory organs of the male
reproductive system.
3. In males, the urethra is involved in
both the ______ and ______
systems.
4. Add to notes:
1. Sperm will stay in the epididymis for 1-3
weeks
2. Cowper’s gland secretes fructose to
nourish sperm
Female reproductive system introduction
• Specialized organs that produce and
maintain egg cells
– Eggs are the sex cells of the female
– Eggs contain half the normal
chromosome number - haploid
• transport cells to site of fertilization
• provide favorable environment for
developing fetus
• give birth
• Produce female sex hormones
Organs of the female
reproductive system
• Primary sex organ – gonad ovaries
• Ovaries – solid, ovoid
structure in lateral pelvic
cavity
– Subdivisions – medulla/cortex
– Cortex contains follicles
Female internal accessory
organs
• Uterine tubes – oviducts –fallopian tube
suspended by ligament – lead to uterus –
where pregnancy usually takes place
– Funnel shaped open ended portion of oviduct
called infundibulum with fimbrae to catch egg
– Have cilia which beat, drawing egg into tube
• Uterus – upper 2/3, body, dome shaped,
– Lower 1/3 cervix, extends into vagina
• Uterine wall – endometrium, myometrium, perimetrium
• Endometrium is sloughed off during menstruation
• Does not serve as a passageway for urine
• Vagina – muscular tube – extends from uterus
to outside
– 3 layers
Female reproductive system
Female sex hormones
• Prenatal – primordial follicles (oocyte surrounded by
follicular cells)
• The process of egg formation is called oogenesis
• Oocytes undergo meiosis but process halts and does
not resume until puberty.
• At about 10, hypothalamus secretes gonadotropic
RH, which stimulates production of Lutenizing
hormone and follicle stimulating hormone
• At puberty FSH initiates follicle maturation
• The LH triggers ovulation
• Secreted by ovary
– Estrogen – responsible for secondary sex characteristic
development at puberty
– Progesterone – trigger uterine changes during
menstrual cycle
Ovulation
• Release of oocyte from surface of
ovary
• Egg will travel down the oviduct to
the site of fertilization
• Triggered by release of LH at day 14
of reproductive cycle
• If not fertilized shortly after release,
degenerates and get sloughed off
during menstruation – shedding of
endometrial lining
Hormones and the menstrual
cycle
Mammary glands
Accessory organs
• Produce and secrete milk
– Prolactin – hormone that triggers milk
production
– Oxytocin – hormone that causes milk to
drop into position
• Location - Anterior thorax
Reflection
1. The process of egg formation is
called _____
2. What are the layers of the uterus?
3. What is the open part of the
oviduct?
4. Where does fertilization take place?
Warm up
• From what you have learned about
the female reproductive system,
what are some things that could go
wrong anatomically or
physiologically when a couple would
like to conceive a child?
Pregnancy – last lesson of the
year!!
• Presence of developing
offspring in uterus
• Transport of Sex Cells
– Upper one third of uterine tubes
– Thin uterine secretions
• Fertilization
– Sperm erode corona radiata and
zona pellucida - one sperm cell
penetrates egg membrane
– Changes in egg membrane
prevent additional sperm from
entering
Prenatal Period
• Early Embryonic Development
– Cleavage
– Morula
– Blastocyst
– Embryo
Hormonal changes during
pregnancy
• Human chorionic gonadotropin
– Maintains corpus luteum and uterine
lining
• Aldosterone
– Promotes fluid retention
• Parathyroid hormone
– Maintains high calcium level
Embryonic Stage of Development
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Weeks 2-8
Placenta development
Internal organ development
Facial feature development
Week 2
• Embryonic disk development
– Germ layers
• Ectoderm - nervous system and sensory organs,
epidermis, linings of mouth and anal canal
• Mesoderm - muscle, bone, marrow, blood, lymphatic
vessels, reproductive organs, kidneys, linings of
cavities
• Endoderm - linings of digestive and respiratory tract,
urinary bladder and urethra
– Yolk sac development - blood cell formation
and stem cells
– Week 3 - allontois forms - forms blood cells
and becomes umbilical arteries and veins
Week 4
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Heart beating
Head and jaw
Limb buds
Gas and nutrient exchange through
placenta
Trophoblast extensions chorionic villi
Week 8
• Amnion develops - amniotic fluid
• Umbilical cord
• Embryo is 30 millimeters in length
and all systems are formed
Fetal Stage of development
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8th week
Growth
Bones begin to ossify
5th month - mother feels movement lanugo and sebum cover skin
• Final trimester - brain cells and
organs mature
• 40 weeks - parturition - birth
Fetal circulation
Birth process
Postnatal Period
• Production and
secretion of milk
– First milk – colostrum
– rich in nutrients and
antibodies
– Milk let down –
triggered by Oxytocin
Neonatal period of development
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Birth - 4 weeks
First breath
Surfactant
Live off fat
Changes in fetal circulation
Tubal ligation
vasectomy
Reflection
• Describe the embryonic and fetal
stages of development and what
happens in each.