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What is a Morula?
the resulting solid ball of cells after fertilization
What is blastocyst?
Modula enters uterus and undergoes reorganization into a hollow ball (blastocyst)
Where does the blastocyst bury itself?
Into the endometrial lining
Summary of ovum becoming a blastocyst
Ovum meets with sperm cell and becomes zygote. Zygote keeps multiplying cells till it becomes Morula. Then Modula becomes a blastocyst
What are 5 stages of embryo division
1. Fertilized egg
2. 4 cell embryo
3. 8 cell embryo
5. Hatching blastocyst
How many stages are in fetal growth?
Stages of fetal growth ) what occurs in the blastogenesis stage (2)
-fertilized egg divides into cells that fold in on one another
-inner cell mass evolves which gives rise to embryo and an outer coat called trophoblast
Stages of fetal growth ) Blastogenensis is complete about ____ weeks after fertilization
What does the trophoblast eventually become
Stages of fetal growth ) what critical thing occurs in embryonic stage?
Critical time when cells differentiate into 3 germinal layers
Stages of fetal growth ) embryonic stage- what are the 3 germinal layers that form?
Stages of fetal growth ) embryonic stage- what is ectoderm (2)
-give rise to the brain, nervous system, hair and skin
Stages of fetal growth ) embryonic stage- what is mesoderm? (2)
-produces all of the voluntary muscles, bones, and components of the cardiovascular and excretory systems
Stages of fetal growth ) embryonic stage- what is the endoderm? (2)
-forms digestive and respiratory systems and glandular organs
Stages of fetal growth ) during embryonic stage, growth occurs in hyperplasia meaning...
There is only an increase in number of cells
By which day have most major features of the human infant been achieved?
What are the 3 stages of fetal growth?
During fetal growth, how is growth occurring?
-growth continues to occur in hyperplasia but now also in hypertrophy.
Placenta) how does the exchange of materials occur between fetus and mother?
- take space within the sponge-like endometrium
- *mother and fetal blood never intermingle
What 3 functions does the placenta provide for the fetus?
How does the fetus remained attached to the placenta?
By umbilical cord
What's within the umbilical cord?
A major fetal artery that runs down the cord into the placenta then branches into each villi and then into capillaries
What does the placenta use as fuel?
Increase blood flow AND placenta
Blood flow to the placenta increases 25% of the cardiac output. The increase in blood flow influences rate of oxygen, nutrient delivery, and waste exchange
What crosses the placenta by passive diffusion (4)
-water, oxygen, carbon dioxide, and electrolytes
What crosses the placenta through active transport? (5)
-and other large nutrients
Placental hormones) what is human chorionic gonadotropin (HCG)? (2)
-produced by chorionic villi of the placenta
-stimulate secretion of estrogen and progesterone
Placental hormones) what is placental lactogen? (2)
-produced by placenta
-stimulate metabolism of glucose to fat
*this is the hormone that starts to lay fat stores for when the fetus starts taking all of the glucose
Placental hormones) estriol
-produced by placenta
-major estrogen of pregnancy
What appears to be the cause of pregnancy women feeling tired and easily exerted in early pregnancy?
The surges in plasma volume
Feb blood cell production and plasma volume
RBC production rises but not as great as plasma volume thus hematocrit and hemoglobin appear to decrease during pregnancy
What happens to the heart during pregnancy? And why?
It slightly increases in size due to the increased in blood volume and cardiac output
Respiration changes in women (2)
-Maternal oxygen requirements increase in response to accelerated metabolic rate
-thoracic breathing replaces abdominal breathing
*may have to take several more breaths to catch breath
Why must Women's kidneys adapt to pregnancy?
Must manage the increase metabolic and circulatory demands of the maternal body as well as the excretion of waster products
BMR adjustments during pregnancy
BMR rises by 4th month of gestation due to increased oxygen demands and consumption
Glucose for fetus ANd later in pregnancy
Fetus demand for glucose causes maternal glucose levels to fall, triggering lipolysis in the mother.
First half of pregnancy, carbs metabolism is characterized by 2 things
-increase in insulin production
-conversion of glucose to glycogen and fat
Second half of pregnancy, carbs metabolism is characterized by? (3)
-rising levels of hCS and prolactin to inhibit conversion of glucose to glycogen and fat
-insulin resistance rises in the mother to increase reliance on fats for energy
-increase glucose production in the liver
***all these are to ensure that there is a constant supply of glucose for fetal growth
Protein metabolism in pregnancy
-increased need for nitrogen and protein for the synthesis of new maternal and fetal tissues
*needs are primarily fulfilled by mothers intake of protein during pregnancy
Changes in calcium metabolism
Increased rate of bone turnover and reformation
Changes in sodium and other minerals metabolism
Increased requirements due to elevated levels of body water and tissue synthesis
Gastro intestinal function changes) what does the increased in progesterone production cause?
Decreased tone and motility of the smooth muscles of the GI tract resulting in constipation and heartburn
Overview of things that change in gastrointestinal function (6)
-vomiting may occur
-intestinal secretion is reduced
-GI motility if diminshed
-sense of taste is altered
-absorption of nutrients is enhanced
Physiological changes occurring in first half of pregnancy (2)
-build the capacity of the mothers body to deliver blood, nutrients, and oxygen tot he fetus in 2nd half
How much of growth occurs in first half of pregnancy?
Physiological changes in pregnancy during 2nd half (2)
-energy and nutrient stores and the increased capacity to deliver stored nutrients and energy to the fetus
How much growth occurs in 2nd half?
Summary of first 20 weeks (6)
-blood volume expansion, increased cardiac output
-build up of fat, nutrient, liver glycogen stores
-growth of some maternal organs
-increased appetite and food intake
-decreased exercise tolerance
-increased levels of anabolic hormones
Summary of the 2nd half (6)
-mobilization of fat and nutrient stores
-increased production and blood levels of of glucose, triglycerides, fatty acids while decreased liver glycogen stores
-accelerated fasting metabolism
-increased appetite and food intake decline somewhat near term
-increased exercise tolerance
-increased levels of catatonic hormones