Chapter 33Chapter 33

Growth and DevelopmentGrowth and Development

New Human LifeNew Human Life

Begins with the production of sex cellsBegins with the production of sex cells In males called spermatogenesisIn males called spermatogenesis In females called oogenesisIn females called oogenesis Occurs due to meiosis (remember Occurs due to meiosis (remember

IPMATPMAT)IPMATPMAT) Gametes special cells in that they are Gametes special cells in that they are

haploids, not diploid, like somatic cellshaploids, not diploid, like somatic cells

SpermatogenesisSpermatogenesis

Begins about the time of puberty, continues throughout Begins about the time of puberty, continues throughout lifelife

A primary spermatocyte (in seminiferous tube) A primary spermatocyte (in seminiferous tube) undergoes meiotic division I, forms two secondary undergoes meiotic division I, forms two secondary spermatocytesspermatocytes

Secondary spermatocytes undergo meiotic division II to Secondary spermatocytes undergo meiotic division II to form four spermatidsform four spermatids

Spermatids differentiate to form head and tailSpermatids differentiate to form head and tail

OogenesisOogenesis Production of female gametes Production of female gametes

During fetal period oogonia (stem cells) multiply by mitosis During fetal period oogonia (stem cells) multiply by mitosis

Oogonia transformed into primordial oocytes (marked by one layer of cells Oogonia transformed into primordial oocytes (marked by one layer of cells suurounding the oocyte) suurounding the oocyte)

Primary oocyte begin the first meiotic division BUT stop at prophase I (about Primary oocyte begin the first meiotic division BUT stop at prophase I (about 500,000 present at birth, around 100,000 will die before puberty)500,000 present at birth, around 100,000 will die before puberty)

During childhood, ganulosa cells develop around primary oocyte to form primary During childhood, ganulosa cells develop around primary oocyte to form primary follicle follicle

Puberty initiates the continuation of oogenesis Puberty initiates the continuation of oogenesis Each cycle, 1000 primary oocytes resume meiosisEach cycle, 1000 primary oocytes resume meiosis Granulosa cells become theca cells—produce androgen (estrogen); now Granulosa cells become theca cells—produce androgen (estrogen); now

secondary folliclessecondary follicles Only 1 will survive and mature into antrum. A mature follicle ready to burst open Only 1 will survive and mature into antrum. A mature follicle ready to burst open

from ovary surface is called a Graafian folliclefrom ovary surface is called a Graafian follicle

Meoisis I results in two daughter cells: a large cell called a secondary Meoisis I results in two daughter cells: a large cell called a secondary oocyte and a small cell called a first polar body oocyte and a small cell called a first polar body

Just before ovulation meiosis stops again, at metaphase IIJust before ovulation meiosis stops again, at metaphase II

LH (luteinizing hormone) causes ovulation to happenLH (luteinizing hormone) causes ovulation to happen

Meiosis II resumes only if the oocyte is penetrated by the head of a spermMeiosis II resumes only if the oocyte is penetrated by the head of a sperm

If fertilization doesn’t happen, the ova disentegratesIf fertilization doesn’t happen, the ova disentegrates

If fertilization does occur, meiotic division continues to produces a If fertilization does occur, meiotic division continues to produces a secondary polar body and a mature, fertilized ovum called a zygotesecondary polar body and a mature, fertilized ovum called a zygote

differencesdifferences

Spermatogenesis produces four spermatozoaSpermatogenesis produces four spermatozoa

Oogenesis produces only one mature ovum Oogenesis produces only one mature ovum and three polar bodies that disintegrate. The and three polar bodies that disintegrate. The cytoplasm is not equally divided among the cytoplasm is not equally divided among the daughter cells, one large fluid filled cell is daughter cells, one large fluid filled cell is necessary to store all of the organelles, necessary to store all of the organelles, nutrients, and regulatory molecules.nutrients, and regulatory molecules.

Ovulation and Ovulation and InseminationInsemination

Ovulation-the expulson of a mature ovum Ovulation-the expulson of a mature ovum from the mature ovarian follicle into the from the mature ovarian follicle into the abdominopelvic cavityabdominopelvic cavity

Insemination-expulsion of the seminal Insemination-expulsion of the seminal fluid from the male urethra to female fluid from the male urethra to female vaginavagina

FertilizationFertilization

After ovum is released into the abdominopelvic After ovum is released into the abdominopelvic cavity, it enters into the fallopian tubecavity, it enters into the fallopian tube

Conception, fertilization, occurs hereConception, fertilization, occurs here An ovum only lives a day or so after ovulation.An ovum only lives a day or so after ovulation. Because sperm may live for a few days in the Because sperm may live for a few days in the

female body, fertilization can occur if sex female body, fertilization can occur if sex occurs any time three days before up to a day occurs any time three days before up to a day after ovulationafter ovulation

A fertilized ovum (zygote) is a diploid. LIFE A fertilized ovum (zygote) is a diploid. LIFE BEGINS—all it needs now is time to go through BEGINS—all it needs now is time to go through growth and developmentgrowth and development

Prenatal PeriodPrenatal Period

Runs from time of conception to birth (39-Runs from time of conception to birth (39-40 wks)40 wks)

The study of this period of development The study of this period of development is called embryologyis called embryology

Cleavage and Cleavage and ImplantationImplantation

A zygote immediately begins to cleave (divide), A zygote immediately begins to cleave (divide), after 3 days it becomes a mass of cells called a after 3 days it becomes a mass of cells called a morulamorula

The morula continues to divide to form a The morula continues to divide to form a blastocyst by the time it reaches the uterusblastocyst by the time it reaches the uterus

10 days from conception, the blastocyst 10 days from conception, the blastocyst implants itself into the uterine liningimplants itself into the uterine lining As the bastocyst develops further, it forms two As the bastocyst develops further, it forms two

cavities called the yolk sac and amniotic cavitycavities called the yolk sac and amniotic cavity

In humans, the yolk sac is not nutritive, it has In humans, the yolk sac is not nutritive, it has other purposes like blood cell productionother purposes like blood cell production

The inner lining mass of the blastocyst that will The inner lining mass of the blastocyst that will form the tissues of the offspringform the tissues of the offspring

The outer layer of the blastocyst called the The outer layer of the blastocyst called the trophoblast, that forms the support for the childtrophoblast, that forms the support for the child

The amniotic cavity becomes fluid filled, shock The amniotic cavity becomes fluid filled, shock absorbing sac, in which the embryo floatsabsorbing sac, in which the embryo floats

The chorion develops into a vital fetal The chorion develops into a vital fetal membrane in the placenta. This allows for membrane in the placenta. This allows for embryonic cirulationembryonic cirulation

The placenta anchors the developing offspring The placenta anchors the developing offspring to the uterus and provides and exchange for to the uterus and provides and exchange for nutrients and waste products from mom to childnutrients and waste products from mom to child

PlacentaPlacenta

Contains maternal and fetal blood supplies—Contains maternal and fetal blood supplies—kept separated by a very thin layer of placental kept separated by a very thin layer of placental tissuetissue

Important endocrine functionImportant endocrine function Secretes human chorionic gonadotropin (HCG)Secretes human chorionic gonadotropin (HCG) HCG stimulates the corpus luteum to secrete HCG stimulates the corpus luteum to secrete

estrogen and progesterone—stopping menstruationestrogen and progesterone—stopping menstruation After week ~16, placental starts secreting its own After week ~16, placental starts secreting its own

estrogen and progesteroneestrogen and progesterone At home preg. Test measure the HCG in urineAt home preg. Test measure the HCG in urine

Periods of DevelopmentPeriods of Development

Pregnancy is about 39 weeks, called Pregnancy is about 39 weeks, called gestation periodgestation period

Is divided into trimestersIs divided into trimesters 11stst goes from first day of last menstrual goes from first day of last menstrual

period to the end of 12 wksperiod to the end of 12 wks 22ndnd goes from end of 12 wks to end of 28wk goes from end of 12 wks to end of 28wk 33rdrd goes from end of 28 wk until the delivery goes from end of 28 wk until the delivery

11stst trimester trimester

Use term zygote when first fertilizedUse term zygote when first fertilized Use term morula (a solid mass of cells Use term morula (a solid mass of cells

after 3 days) and then a blastocyst until it after 3 days) and then a blastocyst until it implants itself into the uterusimplants itself into the uterus

Embryonic starts from fertilization until Embryonic starts from fertilization until end of 8wks, after 8wks until birth use end of 8wks, after 8wks until birth use term fetusterm fetus

11stst trimester con’t trimester con’t

The first trimester (0 - 14 weeks), is one of the The first trimester (0 - 14 weeks), is one of the most crucial for the baby. most crucial for the baby.

Week 1 to week 4Week 1 to week 4 Gender is determinedGender is determined Implantation occurs—bleeding may occur 10-14 Implantation occurs—bleeding may occur 10-14

days after fertilization as the blastocyst imbeds itself days after fertilization as the blastocyst imbeds itself in uterusin uterus

Neural tube forms—will become basis of nervous Neural tube forms—will become basis of nervous system (brain, spinal cord, hair, and skin)system (brain, spinal cord, hair, and skin)

Heart and primitive circulatory system formsHeart and primitive circulatory system forms

Week 5Week 5 First heartbeats beginFirst heartbeats begin – ultrasounds show heart beat – ultrasounds show heart beat

Umbilical cord developsUmbilical cord develops - This the baby's lifeline in utero. It bears - This the baby's lifeline in utero. It bears the responsibility of pumping in oxygen, removing waste, and the responsibility of pumping in oxygen, removing waste, and supplying the necessary nutrients for the remainder of the pregnancy. supplying the necessary nutrients for the remainder of the pregnancy.

Blood is now pumpingBlood is now pumping - All four heart chambers are now functioning - All four heart chambers are now functioning

Most other organs begin to developMost other organs begin to develop - infant's lungs start to appear, - infant's lungs start to appear, along with the brain. along with the brain.

Arm and leg buds appearArm and leg buds appear

Week 6Week 6 The arms and legs continue to developThe arms and legs continue to develop

Brain continues growingBrain continues growing

Lenses of the eyes appearLenses of the eyes appear

Nostrils are formedNostrils are formed - The position of the nose seems to shift into its proper - The position of the nose seems to shift into its proper place as well. Soon, the nerves running from the nose to the brain appear. place as well. Soon, the nerves running from the nose to the brain appear.

Intestines growIntestines grow - Initially these are actually located outside the baby's body - Initially these are actually located outside the baby's body within the umbilical cord. within the umbilical cord.

PancreasPancreas - The baby is now equipped to deal with digestive enzymes and - The baby is now equipped to deal with digestive enzymes and take on processing the insulin and glucagons the body needs to function. take on processing the insulin and glucagons the body needs to function.

Week 7Week 7 Elbows formElbows form, fingers develop, fingers develop

Feet start to appear with tiny notches for the toesFeet start to appear with tiny notches for the toes Ears eyes and nose start to appearEars eyes and nose start to appear - Although they may - Although they may

resemble an alien life form, these all "shift" soon enough into a resemble an alien life form, these all "shift" soon enough into a more normal appearance. more normal appearance.

Intestines continue to form in the umbilical cordIntestines continue to form in the umbilical cord

Teeth begin to develop under the gumsTeeth begin to develop under the gums

Week 8Week 8 Cartilage and bones begin to formCartilage and bones begin to form

The basic structure of the eye is well underwayThe basic structure of the eye is well underway

The tongue begins to developThe tongue begins to develop

Intestines move out of the umbilical cord into the abdomenIntestines move out of the umbilical cord into the abdomen

Body grows and makes roomBody grows and makes room

The fingers and toes have appeared but are webbed and shortThe fingers and toes have appeared but are webbed and short

Baby's length (crown to rump) is 0.61 inch (1.6cm) and weight is Baby's length (crown to rump) is 0.61 inch (1.6cm) and weight is 0.04 ounce (1gm)0.04 ounce (1gm)

Week 9Week 9 Baby has begun movementBaby has begun movement—too small to be felt by mother—too small to be felt by mother

Most joints are formed Most joints are formed

Fetus will curve its fingers around an object placed in the Fetus will curve its fingers around an object placed in the palm of its handpalm of its hand

Fingerprints are already evident in the skinFingerprints are already evident in the skin

Average size this week -- length 0.9 inch (2.3cm), weight Average size this week -- length 0.9 inch (2.3cm), weight 0.07 ounce (2gm)0.07 ounce (2gm)

Week 10Week 10 The most critical part of infant's development is completeThe most critical part of infant's development is complete. .

Now headed into a period of rapid growth. Now headed into a period of rapid growth.

baby's head is now about half its length baby's head is now about half its length

Eyelids fuse shut and irises begin to developEyelids fuse shut and irises begin to develop - Eye color is - Eye color is also determined by this point. also determined by this point.

Placenta begins to function this week or nextPlacenta begins to function this week or next

baby will be about 1.22 inch long (3.1cm) and weigh 0.14 baby will be about 1.22 inch long (3.1cm) and weigh 0.14 ounce (4gm) at the end of this weekounce (4gm) at the end of this week

Week 11Week 11 Nearly all structures and organs are formedNearly all structures and organs are formed and beginning to function. and beginning to function.

Fingers and toes have separatedFingers and toes have separated

Hair and nails begin to growHair and nails begin to grow

The genitals begin to take on the proper gender characteristicsThe genitals begin to take on the proper gender characteristics

Amniotic fluid begins to accumulate as the kidneys begin to functionAmniotic fluid begins to accumulate as the kidneys begin to function - - This fluid, consisting primarily of water, helps provide a cushion for baby This fluid, consisting primarily of water, helps provide a cushion for baby

The muscles in the intestinal walls begin to practice contractions that The muscles in the intestinal walls begin to practice contractions that digest fooddigest food

Baby is about 1.61 inches (4.1 cm) long and weighs 0.25 ounce (7gm).Baby is about 1.61 inches (4.1 cm) long and weighs 0.25 ounce (7gm).

Week 12Week 12 Vocal cords begin to formVocal cords begin to form

eyes begin to move closer togethereyes begin to move closer together

Ears shift to their normal place on the side of the headEars shift to their normal place on the side of the head

Intestines move farther in child's bodyIntestines move farther in child's body

liver begins to functionliver begins to function

pancreas begins to produce insulinpancreas begins to produce insulin

baby's average size is now at a whopping length: 2.13 inches baby's average size is now at a whopping length: 2.13 inches (5.4cm) and weight: 0.49 ounce (14gm)(5.4cm) and weight: 0.49 ounce (14gm)

Week 13Week 13 infant is about 2.91 inches (7.4cm) and weighs around 0.81 ounce (23gm) infant is about 2.91 inches (7.4cm) and weighs around 0.81 ounce (23gm)

begins to practice inhaling and exhaling movementsbegins to practice inhaling and exhaling movements

Eyes and ears continue to move and developEyes and ears continue to move and develop

Baby's neck is getting longerBaby's neck is getting longer, and the chin no longer is resting on chest , and the chin no longer is resting on chest

hands are becoming more functional—starts playing with fisthands are becoming more functional—starts playing with fist

At this point all nourishment is received from the placentaAt this point all nourishment is received from the placenta

should be able to hear heartbeat with a Doppler should be able to hear heartbeat with a Doppler

Week 14Week 14 Thyroid gland has matured and baby begins producing hormonesThyroid gland has matured and baby begins producing hormones

In boys, the prostate gland developsIn boys, the prostate gland develops

In girls, the ovaries move from the abdomen to the pelvisIn girls, the ovaries move from the abdomen to the pelvis

may have learned to suck his thumbmay have learned to suck his thumb

child's bones are getting harderchild's bones are getting harder and stronger and stronger

baby's skin is very transparent baby's skin is very transparent

Lanugo (very fine hair) covers the baby's bodyLanugo (very fine hair) covers the baby's body

baby is 3.42 inches (8.7cm) long and weighs about 1.52 ounces (43 grams) baby is 3.42 inches (8.7cm) long and weighs about 1.52 ounces (43 grams)

Week 1 Week 2Week 3 Week 4 Week 5

Week 6Week 7

Week 8Week 9 Week 10

Week 11

Week 12

Week 13Week 14

Second TrimesterSecond Trimester the honeymoon stage of pregnancy the honeymoon stage of pregnancy

Week 15Week 15 may begin to feel some fluttering movementsmay begin to feel some fluttering movements as baby kicks, flails, as baby kicks, flails,

twists and turns twists and turns

baby's legs have grownbaby's legs have grown longer than the arms and the body is now longer longer than the arms and the body is now longer than the head. than the head.

skin is very thinskin is very thin -- so thin blood vessel are visible. It's covered by a fine, -- so thin blood vessel are visible. It's covered by a fine, soft layer of hair called lanugo. Lanugo comes from a Latin word meaning soft layer of hair called lanugo. Lanugo comes from a Latin word meaning "down." This hair is thought to help insulate."down." This hair is thought to help insulate.

Incus, malleus,and stapes in middle ear have begun to hardenIncus, malleus,and stapes in middle ear have begun to harden. .

Fingernails and toenails are growing; Eyebrows are beginning to Fingernails and toenails are growing; Eyebrows are beginning to growgrow

Baby is 3.98 inches (10.1cm) long and may weigh 2.47 ounces Baby is 3.98 inches (10.1cm) long and may weigh 2.47 ounces (70gm)(70gm). .

Week 16Week 16 Fat begins to form underneath skinFat begins to form underneath skin

baby and placenta are now about the same sizebaby and placenta are now about the same size

Baby is Baby is 4.57 inches (11.6cm) and approximately 3.53 ounces 4.57 inches (11.6cm) and approximately 3.53 ounces (100gm)(100gm). .

head and neck are held straighterhead and neck are held straighter

might hear the tiny thumps of his heartbeat with an external might hear the tiny thumps of his heartbeat with an external monitor; might be able to determine gendermonitor; might be able to determine gender

Heart is pumping as much as 6 gallons of blood a dayHeart is pumping as much as 6 gallons of blood a day and beats and beats

at a rate about double maternal heart rate. at a rate about double maternal heart rate.

Sucking, swallowing and blinking are now evidentSucking, swallowing and blinking are now evident

baby has learned to breathe—inhales and exhales small amounts of baby has learned to breathe—inhales and exhales small amounts of amniotic fluid amniotic fluid

Week 17Week 17 baby weighs about 4.97 ounces (140gm) and is 5.12 inches (13cm) long baby weighs about 4.97 ounces (140gm) and is 5.12 inches (13cm) long

has a much more normal "human" appearance has a much more normal "human" appearance

Pads are forming on his tiny fingertips and toesPads are forming on his tiny fingertips and toes

eyes are looking forward now,eyes are looking forward now, but they are still firmly closed. but they are still firmly closed.

Meconium (composed of products of cell loss, digestive secretion Meconium (composed of products of cell loss, digestive secretion and swallowed amniotic fluid), is accumulating in the boweland swallowed amniotic fluid), is accumulating in the bowel. This . This black gooey substance will become baby's first poop! black gooey substance will become baby's first poop!

The umbilical cord is growing thicker and strongerThe umbilical cord is growing thicker and stronger

the prostate begins to develop in malesthe prostate begins to develop in males

skeleton is transforming from cartilage to boneskeleton is transforming from cartilage to bone

Week 18Week 18 Vernix (a white cheese-like protective material) forms on Vernix (a white cheese-like protective material) forms on

baby's skinbaby's skin with the lanugo (soft, lightly pigmented hair with the lanugo (soft, lightly pigmented hair covering the body and limbs); both serving to protect baby's covering the body and limbs); both serving to protect baby's skin during the months in water. skin during the months in water.

Tiny air sacs called alveoli begin to form in lungsTiny air sacs called alveoli begin to form in lungs

vocal chords are formedvocal chords are formed. Baby goes through the motions . Baby goes through the motions of crying but without air doesn't make a sound of crying but without air doesn't make a sound

Features of baby's heart, including ventricles and Features of baby's heart, including ventricles and chambers, should be visiblechambers, should be visible during an ultrasound. during an ultrasound.

baby measures about baby measures about 5.59 inches (14.2cm) this week and 5.59 inches (14.2cm) this week and weighs about 6.7 ounces (190gm)weighs about 6.7 ounces (190gm)

Week 19Week 19 baby has the same awake and sleep patterns of a newbornbaby has the same awake and sleep patterns of a newborn. .

nerves are being coated with a fatty substance called myelinnerves are being coated with a fatty substance called myelin, , which insulates the nerves so that impulses can flow smoothly. which insulates the nerves so that impulses can flow smoothly.

Scalp hair becomes apparentScalp hair becomes apparent

The milk teeth buds have already developedThe milk teeth buds have already developed and over the next and over the next few days the buds for the permanent teeth will begin to form behind few days the buds for the permanent teeth will begin to form behind the milk teeth. the milk teeth.

If baby is female If baby is female the uterus starts to develop--the uterus starts to develop--the vagina, uterus, the vagina, uterus, and fallopian tubes are in place. and fallopian tubes are in place.

If it's a boy, If it's a boy, the genitals are distinct and recognizablethe genitals are distinct and recognizable. .

baby is swallowing amniotic fluid and his or her kidneys are baby is swallowing amniotic fluid and his or her kidneys are making urinemaking urine

size is around size is around 6.02 inches (15.3cm) and 8.47 ounces (240gm)6.02 inches (15.3cm) and 8.47 ounces (240gm)

Week 20Week 20

The rapid growth stage is about overThe rapid growth stage is about over

The baby's heart grows stronger—may be able to feel heartbeat through abdomenThe baby's heart grows stronger—may be able to feel heartbeat through abdomen

legs are reaching their relative sizelegs are reaching their relative size

Immunities are being transferredImmunities are being transferred from mother to baby now. These immune cells will from mother to baby now. These immune cells will protect baby from viruses mother has already had for up to six months after birthprotect baby from viruses mother has already had for up to six months after birth

The nerve cells for taste, smell, hearing, seeing, and touch are now developingThe nerve cells for taste, smell, hearing, seeing, and touch are now developing in in specialized areas of the brain. Production slows down as existing nerve cells grow specialized areas of the brain. Production slows down as existing nerve cells grow larger and make more complex connections. larger and make more complex connections.

baby may startlebaby may startle in reaction to loud sounds. Amazingly, can actually hear noises in reaction to loud sounds. Amazingly, can actually hear noises outside of the womb. Familiar voices, music, and sounds that baby becomes outside of the womb. Familiar voices, music, and sounds that baby becomes accustomed to during development stages often are calming after birth. accustomed to during development stages often are calming after birth.

girl, girl, uterus is starting to developuterus is starting to develop. She has approximately six million . She has approximately six million eggseggs in her in her ovaries. About one million will remain at birth. ovaries. About one million will remain at birth.

Baby is about Baby is about 6.46 inches (16.4cm) and weighs around 10.58 ounces (300g6.46 inches (16.4cm) and weighs around 10.58 ounces (300g ) )

Week 21Week 21

White blood (leukocytes) cells are under productionWhite blood (leukocytes) cells are under production

skin has changed from translucent to become more skin has changed from translucent to become more opaqueopaque. .

infant's tongue is fully formed infant's tongue is fully formed

womb and vagina are formed womb and vagina are formed

Baby swallows more this weekBaby swallows more this week. After baby takes in amniotic . After baby takes in amniotic fluid, body absorbs the water in the liquid and moves the rest fluid, body absorbs the water in the liquid and moves the rest into the large bowel--- good practice for digestive systeminto the large bowel--- good practice for digestive system

Wake and sleep periods become more consistentWake and sleep periods become more consistent

Baby measures about Baby measures about 10.51 inches (26.7cm) and weighs 10.51 inches (26.7cm) and weighs nearly 12.7 ounces (360g)nearly 12.7 ounces (360g). .

Week 22Week 22 When mother talks, reads, or sings, expect baby to hear youWhen mother talks, reads, or sings, expect baby to hear you. Studies . Studies

have found that newborns will suck more vigorously when read to from a book have found that newborns will suck more vigorously when read to from a book they heard frequently in utero. they heard frequently in utero.

Eyelids and eyebrows are fully formedEyelids and eyebrows are fully formed. .

Fingernails have grown to the end of the fingersFingernails have grown to the end of the fingers

Baby's brain has entered a stage of rapid growthBaby's brain has entered a stage of rapid growth, especially in what's , especially in what's called the germinal matrix. This structure deep in the middle of the brain called the germinal matrix. This structure deep in the middle of the brain serves as a kind of factory for brain cells and disappears shortly before birth. serves as a kind of factory for brain cells and disappears shortly before birth. But the brain's amazing expansion program continues until around the five But the brain's amazing expansion program continues until around the five birthday. birthday.

baby's liver is starting to break down bilirubinbaby's liver is starting to break down bilirubin, a substance produced by , a substance produced by red blood cells that is involved in the catabolism of biological molecules. red blood cells that is involved in the catabolism of biological molecules. What causes yellow color in bruise and brown color in fecesWhat causes yellow color in bruise and brown color in feces

Testes begin their descent to the scrotum--Primitive sperm have formed Testes begin their descent to the scrotum--Primitive sperm have formed and he is producing testosteroneand he is producing testosterone. .

Length is Length is 10.94 inches (27.8cm); weight is nearly 1 pound (430gm)10.94 inches (27.8cm); weight is nearly 1 pound (430gm). .

Week 23Week 23 Proportions of the body are now quite similar to a Proportions of the body are now quite similar to a

newborn—little to no fatnewborn—little to no fat

eyes are formed, though the iris still lacks eyes are formed, though the iris still lacks pigmentationpigmentation

The pancreas, essential in the production of The pancreas, essential in the production of hormones, is developing steadilyhormones, is developing steadily –insulin is now –insulin is now being producedbeing produced

If born now, baby has a 15% chance of survivalIf born now, baby has a 15% chance of survival

average baby at this stage average baby at this stage weighs 1.1 pound (501gm) weighs 1.1 pound (501gm) and is 11.38 inches (28.9cm) longand is 11.38 inches (28.9cm) long

Week 24Week 24 Baby gains about 6 ounces this weekBaby gains about 6 ounces this week. The weight is in muscle, . The weight is in muscle,

bone mass and organs bone mass and organs

Taste buds begin to formTaste buds begin to form. If mom drinks something strange or . If mom drinks something strange or bitter, baby may be observed showing distaste bitter, baby may be observed showing distaste

Little creases have appeared on palms. The muscular coordination Little creases have appeared on palms. The muscular coordination of hands has improved as sucks thumbof hands has improved as sucks thumb

lungs are developing "branches “lungs are developing "branches “

baby is officially considered viable baby is officially considered viable

Baby weighs Baby weighs 1.3 pound (600gm) and is 11.8 inches (30cm) long1.3 pound (600gm) and is 11.8 inches (30cm) long

Week 25Week 25 structures of the spine begin to formstructures of the spine begin to form

Blood vessels of the lungs developBlood vessels of the lungs develop

Nostrils open--study out of Belfast that suggests babies at Nostrils open--study out of Belfast that suggests babies at this stage have the capability of scent preferences this stage have the capability of scent preferences

nerves around the mouth and lip area are showing more nerves around the mouth and lip area are showing more sensitivitysensitivity

Dexterity is improvingDexterity is improving

approximate length of approximate length of 13.6 inches (34.6cm) and weighs 13.6 inches (34.6cm) and weighs 1.46 pound (660gm)1.46 pound (660gm)

Week 26Week 26 weigh about weigh about two pounds now (average is 1.7 pound, two pounds now (average is 1.7 pound,

760gm) and is 14 inches (35.6cm) in length760gm) and is 14 inches (35.6cm) in length

the spine is getting stronger and more supplethe spine is getting stronger and more supple

Air sacs in the lungs form--Lungs begin to secrete a Air sacs in the lungs form--Lungs begin to secrete a greasy substance called surfactant. Without surfactant greasy substance called surfactant. Without surfactant the fetal lungs would stick together and couldn't expand the fetal lungs would stick together and couldn't expand after the baby is bornafter the baby is born

baby's eyes are opening and beginning to blinkbaby's eyes are opening and beginning to blink

Retinas begin to formRetinas begin to form. .

Brain wave activity for hearing and sight begins to be Brain wave activity for hearing and sight begins to be detectabledetectable. .

Fetal brain scans show response to touchFetal brain scans show response to touch

Week 27Week 27 Response to sound grows more consistentResponse to sound grows more consistent – –

baby recognizes mother and father’s voicebaby recognizes mother and father’s voice

Lungs continue to grow and prepare for Lungs continue to grow and prepare for functioning outside of the wombfunctioning outside of the womb

Eyelids are now open moreEyelids are now open more-- baby can -- baby can distinguish between light and dark distinguish between light and dark

Average size is now Average size is now 14.4 inches (36.6cm) and 14.4 inches (36.6cm) and 1.9 pound (875gm)1.9 pound (875gm)

Week 28Week 28 Eyebrows and eyelashes are now very noticeableEyebrows and eyelashes are now very noticeable

Eyes are completely formed nowEyes are completely formed now

baby's body is getting plump and roundedbaby's body is getting plump and rounded. Most of . Most of that increase is muscle tissue and bone. Fat will be that increase is muscle tissue and bone. Fat will be added during the third trimester added during the third trimester

Muscle tone is improvingMuscle tone is improving

Lungs are capable of breathing nowLungs are capable of breathing now (but baby would (but baby would still struggle and require medical attention if born now )still struggle and require medical attention if born now )

baby weighs in now at baby weighs in now at 2.2 pounds (1005gm) and is 14.8 2.2 pounds (1005gm) and is 14.8 inches (37.6cm)inches (37.6cm). .

Third TrimesterThird Trimester

Week 29Week 29 Fat continues to accumulate under the skinFat continues to accumulate under the skin

BBaby's brainaby's brain can control primitive breathing and body can control primitive breathing and body temperatures. temperatures.

eyes can moveeyes can move in their sockets in their sockets

moving from side to side---still in head up positionmoving from side to side---still in head up position

length is now approximately length is now approximately 15.2 inches (38.6cm) and 15.2 inches (38.6cm) and weight is 2.54 pounds (1153gm)weight is 2.54 pounds (1153gm)

Week 30Week 30 Early lanugo is beginning to disappearEarly lanugo is beginning to disappear

Toenails are entering their final growth stageToenails are entering their final growth stage . .

Bone marrow is now in charge of red blood Bone marrow is now in charge of red blood cell productioncell production

Baby produces tearsBaby produces tears

baby is now baby is now 15.7 inches (39.9cm) long and 15.7 inches (39.9cm) long and weighs 2.91 pounds (1319gm)weighs 2.91 pounds (1319gm)

Week 31Week 31 Fat continues accumulatingFat continues accumulating

Calcium, phosphorus and iron are being stored and Calcium, phosphorus and iron are being stored and bones are growing and hardeningbones are growing and hardening

baby is baby is 16.2 inches (41.1cm) long and weighs 3.3 16.2 inches (41.1cm) long and weighs 3.3 pounds (1502gm)pounds (1502gm)

may move to the rhythm of musicmay move to the rhythm of music. Studies with heart . Studies with heart rates show that prefers some types of music to othersrates show that prefers some types of music to others

Lungs are the only major organ left to complete Lungs are the only major organ left to complete developmentdevelopment

Week 32Week 32 baby is up to baby is up to 3.75 pounds (1702gm) now and is 3.75 pounds (1702gm) now and is

16.7 inches (42.4cm) long16.7 inches (42.4cm) long

not moving around as much---running out of roomnot moving around as much---running out of room

All five senses are workingAll five senses are working

babies have periods of dream sleep (REM) babies have periods of dream sleep (REM) starting around the eight monthstarting around the eight month

Week 33Week 33 Amniotic fluid is at its highest levelAmniotic fluid is at its highest level

Neurons and synapses are developing in huge Neurons and synapses are developing in huge numbers—can now coordinate sucking, numbers—can now coordinate sucking, swallowing, and breathingswallowing, and breathing

testicles will be descending from abdomen to testicles will be descending from abdomen to scrotumscrotum

Baby is now 17.2 inches (43.7cm) long and Baby is now 17.2 inches (43.7cm) long and weighs 4.23 pounds (1918gm)weighs 4.23 pounds (1918gm). .

Week 34Week 34

baby may have already turned to a head-down positionbaby may have already turned to a head-down position in in preparation for birth preparation for birth

length is length is 17.7 inches (45cm) and weight is 4.7 pounds (2146 g)17.7 inches (45cm) and weight is 4.7 pounds (2146 g). .

Week 35Week 35

Most babies born now will surviveMost babies born now will survive and without many long-term and without many long-term problems problems

baby is now taking up most of the uterus baby is now taking up most of the uterus

baby is baby is 18.2 inches (46.2cm) long and weighs 5.3 pounds 18.2 inches (46.2cm) long and weighs 5.3 pounds (2383gm)(2383gm). .

The testes have completed their descent in malesThe testes have completed their descent in males

Week 36Week 36 baby may drop into the birth canalbaby may drop into the birth canal

Fat is dimpling your baby's elbows and Fat is dimpling your baby's elbows and kneesknees, and forming creases in the neck and , and forming creases in the neck and wrists wrists

average size is now average size is now 18.66 inches (47.4cm) and 18.66 inches (47.4cm) and 5.78 pounds (2622 g)5.78 pounds (2622 g). Between now and birth . Between now and birth will gain about an ounce a day will gain about an ounce a day

Week 37Week 37 average size is about average size is about 6.3 pounds (2859gm) now 6.3 pounds (2859gm) now

and 19.1 inches (48.6cm) lengthand 19.1 inches (48.6cm) length

official full term nowofficial full term now but can still benefit from but can still benefit from extra days in the womb extra days in the womb

turns towards light outside the uterus turns towards light outside the uterus

develops definite daily activity cycles—keep develops definite daily activity cycles—keep yourself on sleep cycle to develop night/day yourself on sleep cycle to develop night/day differentiation in baby differentiation in baby

Week 38Week 38 average baby," weights average baby," weights 6.8 pounds 6.8 pounds

(3083gm)and is 19.6 inches (49.8cm) long(3083gm)and is 19.6 inches (49.8cm) long

amniotic fluid to get into windpipe---resulting amniotic fluid to get into windpipe---resulting in Hiccupsin Hiccups

child's intestines are accumulating lots of child's intestines are accumulating lots of meconium meconium

Circumference of head and abdomen are Circumference of head and abdomen are about the same size for babyabout the same size for baby

Week 39Week 39 The lanugo has mostly disappearedThe lanugo has mostly disappeared

lungs are maturing and surfactant production is increasing lungs are maturing and surfactant production is increasing

body continues body continues laying on the fat stores that will help laying on the fat stores that will help regulate body temperature after birthregulate body temperature after birth. In addition to . In addition to normal fat, is accumulating normal fat, is accumulating Brown adipose tissue (BAT)Brown adipose tissue (BAT) "brown" fat in the nape of neck, between shoulders and "brown" fat in the nape of neck, between shoulders and around organs. Brown fat cells are important for around organs. Brown fat cells are important for thermogenesis (generating heat) during first weeks of life.thermogenesis (generating heat) during first weeks of life.

infant's weight is around infant's weight is around 7.25 pounds (3288gm) and 7.25 pounds (3288gm) and length is 19.9 inches (50.7cm)length is 19.9 inches (50.7cm)

Week 40Week 40 15% of your child's body is fat15% of your child's body is fat

Small breast buds are present on both sexesSmall breast buds are present on both sexes

Birth occurs at any timeBirth occurs at any time

Average baby now weighs Average baby now weighs 7.6 pounds (3462gm) 7.6 pounds (3462gm) and is 20.2 inches (51.2cm) longand is 20.2 inches (51.2cm) long

laborlabor

Term used to describe the process that results in birthTerm used to describe the process that results in birth

Three stages:Three stages: One: period from the onset of uterine contractions until One: period from the onset of uterine contractions until

dilation of cervix is complete (10cm)dilation of cervix is complete (10cm)

Two: period from the time of maximal cervical dilation until Two: period from the time of maximal cervical dilation until baby exits vaginababy exits vagina

Three: process of expulsion of the placenta through the Three: process of expulsion of the placenta through the vaginavagina

Average time of stage one labor is 6-24 Average time of stage one labor is 6-24 hrs. (first pregnancies usually the longest hrs. (first pregnancies usually the longest and hardest)and hardest)

Stage two lasts up to one hourStage two lasts up to one hour

Stage three 15 minutes after birthStage three 15 minutes after birth

Ultrasound PicturesUltrasound Pictures

3-D Sonogram Pictures3-D Sonogram Pictures

Problems during Problems during Pregnancy and Pregnancy and

parturition parturition Implantation DisordersImplantation Disorders

Ectopic pregnancy: blastocyst implants itself in Ectopic pregnancy: blastocyst implants itself in endometriosis region, normal peritoneal endometriosis region, normal peritoneal membranes, or in the oviductmembranes, or in the oviduct

If the tissue can stretch, may be able to develop child full If the tissue can stretch, may be able to develop child full term—must be delivered C-sectionterm—must be delivered C-section

Tubal pregnancies result in rupture and life-threatening Tubal pregnancies result in rupture and life-threatening hemorrhaging (most common type of ectopic pregnancy)hemorrhaging (most common type of ectopic pregnancy)

Placenta previaPlacenta previa Blastocyst implants in the uterine wall at or Blastocyst implants in the uterine wall at or

near cervixnear cervix

May cause massive blood loss during third May cause massive blood loss during third trimester—threatens both mother and childtrimester—threatens both mother and child

Will be placed on bed restWill be placed on bed rest

Abruptio placentaeAbruptio placentae Separation occurs of the placenta from the uterine Separation occurs of the placenta from the uterine

wallwall

Occurs around 20 wksOccurs around 20 wks

Complete separation causes immediate death of Complete separation causes immediate death of fetus; severe hemorrhaging occurs causing fetus; severe hemorrhaging occurs causing circulatory shock and death of mother in minutescirculatory shock and death of mother in minutes

C section and/or historectomy must be performed C section and/or historectomy must be performed immediately to save motherimmediately to save mother

Blood Pressure—Blood Pressure—Unknown causeUnknown cause

PIHPIH Pregnancy induced hypertension raises bp in women—will be on bed rest if not Pregnancy induced hypertension raises bp in women—will be on bed rest if not

able to control with meds.able to control with meds.

6-8% of PIH results in 6-8% of PIH results in preeclampsia preeclampsia (toxemia)(toxemia) Severe blood pressure increase, edema, protein in urine (kidney failure)Severe blood pressure increase, edema, protein in urine (kidney failure)

May result in abruptio placentae, stroke, hemorrhage, fetal malnutrition, low birth May result in abruptio placentae, stroke, hemorrhage, fetal malnutrition, low birth weightweight

SymptomsSymptoms Rapid weight gain Rapid weight gain Swelling of the arms or face Swelling of the arms or face Headache Headache Changes in vision (blurred vision, seeing double, seeing spots of light) Changes in vision (blurred vision, seeing double, seeing spots of light) Dizziness, faintness Dizziness, faintness Ringing in the ears Ringing in the ears Abdominal pain Abdominal pain Decreased production of urine Decreased production of urine Nausea, vomiting Nausea, vomiting Blood in vomit or urine Blood in vomit or urine Confusion Confusion

Preeclampsia may lead to Preeclampsia may lead to eclampsiaeclampsia life threateninglife threatening

Causes severe convulsions, coma, kidney failure, heart related Causes severe convulsions, coma, kidney failure, heart related problems, death of mother and fetusproblems, death of mother and fetus

Risk factorsRisk factors

First pregnancies (first child with new partner)First pregnancies (first child with new partner) Mother or sister having preeclampsia or eclampsiaMother or sister having preeclampsia or eclampsia Teenage pregnancies Teenage pregnancies Being 35 or older Being 35 or older Being African-American Being African-American Multiple pregnancies (twins, triplets, etc.) Multiple pregnancies (twins, triplets, etc.) History of diabetes, hypertension, or renal disease History of diabetes, hypertension, or renal disease

Hiatal herniaHiatal hernia Upward pressure causes abdominal organs Upward pressure causes abdominal organs

to push against diaphram, stomach to push against diaphram, stomach protrudes into the thoracic cavityprotrudes into the thoracic cavity

Sensory and coordination changesSensory and coordination changes Control systems often do not compensate Control systems often do not compensate

for shift in center of gravityfor shift in center of gravity

Fetal DeathFetal Death

MiscarriageMiscarriage Loss of embryo before 12Loss of embryo before 12thth wk wk

Spontaneous abortionSpontaneous abortion

May be caused by hypertension, uterine May be caused by hypertension, uterine abnormalities, and hormonal imbalancesabnormalities, and hormonal imbalances

After 20 wks, called stillbirth (labor and delivery of a After 20 wks, called stillbirth (labor and delivery of a dead fetus)dead fetus)

Birth DefectsBirth Defects

Congenital abnormalities—will study further Congenital abnormalities—will study further during genetics.during genetics.

Any structural or functional abnormality that is Any structural or functional abnormality that is inherited or acquired during gestation or deliveryinherited or acquired during gestation or delivery

Alcohol, antibiotics, radiation, microorganisms, Alcohol, antibiotics, radiation, microorganisms, etc. that cause defect are called teratogensetc. that cause defect are called teratogens

Postpartum disordersPostpartum disorders

Preeclampsia and eclampsia may Preeclampsia and eclampsia may continue to cause problems after birthcontinue to cause problems after birth

Puerperal fever: a syndrome Puerperal fever: a syndrome characterized by bacterial infection that characterized by bacterial infection that becomes septicemia (infection of blood) becomes septicemia (infection of blood) and possible death (leading cause of ~ and possible death (leading cause of ~ 20% maternal death until 1930s)20% maternal death until 1930s)

Depression: hormonal changes may Depression: hormonal changes may cause clinical depression in postpartum cause clinical depression in postpartum mothermother

Mastitis: breast inflammationMastitis: breast inflammation