Chapter 5 Nutrition during Pregnancy: Conditions & Interventions.
Chapter 16 Pregnancy & Development
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Transcript of Chapter 16 Pregnancy & Development
Chapter 16Pregnancy & Development
Notice: This presentation contains actual pictures of human reproductive anatomy
Menstrual (Uterine) CycleMenstrual (Uterine) Cycle Cyclic changes of endometrium
Regulated by estrogens & progesterone
Stages
1. Menses – endometrium is sloughed
2. Proliferative stage – regeneration of functional layer
3. Secretory stage –increases in size & readies for implantation
Menarche – 1st period
Hormonal Control of Ovarian & Uterine CyclesHormonal Control of Ovarian & Uterine Cycles
Hormonal Control of Ovarian & Uterine CyclesHormonal Control of Ovarian & Uterine Cycles
Hormones of OvariesHormones of Ovaries1. Estrogens Produced by follicle cells
Cause secondary sex characteristics
1. Development of breasts
2. Appearance of pubic hair
3. Increase in fat beneath the skin
4. Widening and lightening of the pelvis
5. Onset of menses
2. Progesterone
Produced by the corpus luteum
Production continues until LH diminishes in the blood
Helps maintain pregnancy
Mammary GlandsMammary Glands Present in both sexes,
but only function in females
- Modified sweat glands
produce milk
Stimulated by sex hormones (mostly estrogens) to increase in size
Anatomy of Mammary GlandsAnatomy of Mammary Glands Areola – central pigmented area
Nipple – protruding central area of areola
Lobes – internal structures that radiate around nipple
Alveolar glands – clusters of milk producing glands within lobules
Lactiferous ducts – connect alveolar glands to nipple
Stages of Pregnancy & DevelopmentStages of Pregnancy & Development
Fertilization
Embryonic development
Fetal development
Childbirth
FertilizationFertilization Oocyte viable 12 - 24 hrs
Sperm viable 12 - 48 hrs
Sperm swim to fallopian tube for fertilization
At least 20 million sperm/ml needed
Mechanisms of FertilizationMechanisms of Fertilization Membrane receptors of oocyte pull in head of the first
sperm cell to make contact
Membrane of oocyte stops other sperm
Oocyte undergoes 2nd meiotic division
Fertilization: sperm nucleus + oocyte nucleus = zygote.
The ZygoteThe Zygote First cell of new individual
Zygote begins rapid mitotis
Zygote stage is in the uterine tube, moving toward the uterus
The EmbryoThe Embryo
Developmental stage: cleavage thru 9th week
Undergoes division w/o growth at first
Embryo enters uterus at 16-cell state
Embryo floats in the uterus temporarily
Uterine secretions used for nourishment
The BlastocystThe Blastocyst Ball-like circle of cells
Begins at ~ 100 cells
Secretes human chorionic gonadotropin (hCG) to produce the corpus luteum to continue producing hormones (test)
Functional areas of the blastocyst
- Trophoblast – large fluid-filled sphere
- Inner cell mass
The late blastocyst implants in the wall of the uterus (by day 14)
Gastrulation
- Blastocyst folds in on itself
- Primary germ layers formed
Derivatives of Germ LayersDerivatives of Germ Layers
1. Ectoderm
Nervous system
Epidermis
2. Endoderm
Mucosae
Glands
3. Mesoderm
Everything else
Development (Development (Ovulation to ImplantationOvulation to Implantation))
Development After ImplantationDevelopment After Implantation
Chorionic villi (projections of the blastocyst) develop
- Cooperate with cells of the uterus to form the placenta
Embryo surrounded by amnion (fluid filled sac)
Umbilical cord forms
Development After ImplantationDevelopment After Implantation
Functions of PlacentaFunctions of Placenta Barrier between
mother & embryo (blood not exchanged)
Delivers nutrients & O2
Removes waste
Becomes endocrine organ (produces hormones) and takes over for the corpus luteum
Estrogen
Progesterone
Other hormones that maintain pregnancy
The Fetus (The Fetus (Beginning of the Ninth WeekBeginning of the Ninth Week))
All organ systems formed by the end of the 8th week
Time for organ specialization
Stage of tremendous growth and change in appearance
Effects of Pregnancy on the MotherEffects of Pregnancy on the Mother
Pregnancy – conception until birth
Anatomical changes
- Enlargement of uterus
- Accentuated lumbar curvature
- Relaxation of pelvic ligaments and pubic symphysis due to production of relaxin
Effects of Pregnancy on the MotherEffects of Pregnancy on the Mother Physiological changes
A. Gastrointestinal system
Morning sickness - elevated progesterone
Heartburn - organ crowding by the fetus
Constipation - digestive tract slows
B. Urinary System
Kidneys – work more/more urine
Uterus compresses bladder
Effects of Pregnancy on the MotherEffects of Pregnancy on the MotherC. Respiratory System
Nasal mucosa congested and swollen
Vital capacity & respiratory rate increase
D. Cardiovascular system
Body water rises
Blood volume increases 25 to 40%
Blood pressure & pulse increase
Varicose veins common
Childbirth (Partition)Childbirth (Partition)
1. Labor – events that expel infant from uterus
2. Initiation of labor
Estrogen levels rise
Uterine contractions begin
Placenta releases prostaglandins
Oxytocin is released by the pituitary
Contractions
Labor Contractions -+ Feedback
Stages of LaborStages of Labor
Developmental AspectsDevelopmental Aspects Gender determined at fertilization
- Males = XY; Females = XX
- Gonads form starting week 8
Testes in abdominal cavity; descend to scrotum 1 month before birth
Testosterone determines ovaries or testes.
Reproductive organs not functional until puberty
Puberty - begins ages 10 - 15
1st menses occurs ~ 2 yrs after puberty starts
Peak reproductive ability - late 20s
Developmental AspectsDevelopmental Aspects
Menopause - ovulation & menses stop
- Ovaries stop functioning as endocrine organs
No equivalent of menopause in males, but there is a steady decline in testosterone