83 terms

Reproduction Physiology

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The Two Phases of Human Development
The Prental Phase and the Postnatal Phase
Zygote Formation
When the sperm cell penetrates the egg. At this point, it looses it's tail
The Zygotic Period of Prenatal Development
This period begins at the moment of fertilization and ends at the end of day Seven
The Embryotic Period of Prenatal Development
This Period follows the Zygotic Period, and begins at day Eight and lasts until the last day of week 8
The Fetal Period of Prenatal Development
This begins on the first day of day 9 and ends at birth
Gestation Period
The time of all prenatal activity
Clevages
A series of mitotic divisions following zygote formation, divides into two
Ampulla
The center part of the fallopian tube where fertilization takes place
Blastomeres
Daughter Cells
Daughter Cell Size
Half the size of the parent cell, due to lack of nutrition. Zygote size doesn't change
Morula
A solid mass of cells that results from clevage following fertilization (Day 3)
Blastocyst
When the morula changes into a fluid filled hallow sphere (Day 4 to 5)
Trophoblast Cells
The surrounding layer of epithelial cells in a blastocyte
Inner Cell Mass
One end of a blastocyst
Chorion
Used for waste removal for the developing child, developed from trophoblasts
Blastocell
The hollow, fluid filled part of the blastocyst
Day 6
The time when the blastocyst has reached and floats inside the Uterus. Once inside, it will recieve nutrition and grow, preparing for implatation to the uterine wall
Day 7
The time when pregnancy is said to begin. The blastocyst is completely enclosed in the endomertrium
Human Chorionic Gonadotropin
A hormone SNS by Trophoblast cells that helps maintain levels of estrogen and progesterone, both needed to maintain the endometrium
Week Two
The time when the ICM (Inner Cell Mass) changes into a bi-laminar, then a tri-laminar disk. Also, the amniotic cavity, body stalk, and the chorion develop
Differentiation
The process following implantation, where cell division changes to produce different types of cells. This allows cells to form specialized organs and tissues
Primary Germ Layers
The three layers that the tri-laminar disk will develop into during Differentiation; Ectoderm, Mesoderm, Endoderm
Ectoderm
Skin, hair and the entire nervous system develop from this layer
Mesoderm
Connective tissue (Blood, Cartilage, and Lymph tissue), and skeletal muscle develop from this layer
Endoderm
GI system and the genitalia develop from this layer
Extra Embryonic Membranes
Develop from trophoblast cells during Differentiation
Chorionic Villi
Small extensions developed from the chorion, which grow into one of the layers of the placenta, allowing for the exchange of nutrients
Yoke Sack
Functions as primative early digestive and respiratory organs. The amnion surrounds the embryo, the membrane is filled with amniotic fluid for shock absorption and allows the child to move
Week 6
The time when the yoke sack degenerates and is incorporated into the umbilical cord
Placenta
At the site of implantation, where the Chorion joins with the Endometrium, in place by the forth week
Fetal side of the Placenta
This is smooth
Maternal side of the Placenta
This is very rough with many projections to increase surface area to facilitate with the exchange between maternal and fetal circulation
Non Placenta Exchanges
Blood exchange between the mother and the baby, and nervous system connection
Placenta Exchanges
Respiratory gases, nutrients, vitamins, hormones, drugs and antibodies, by the process of diffusion and active transport
Placenta Functions
Synthesizes Glycogen and fatty acids, also SNS Hormones like HCG, Estrogen, and Progesterone
Umbilical Cord
The life-line, connects the baby to the Placenta
Umbilical Cord Contents
Two Arteries which carry CO2 and wastes from the embryo/fetus to the Placenta, and One vein to carry O2 and nutrients to the embryo/fetus from the Placenta
Development: Week 1
Cleavage of the cells is the major event
Development: Week 2
Differentiation begins
Development: Week 3
Primary germ layers and cardiovascular system develops
Development: Week 4
Heart starts beating
Development: Week 5
Rapid Brain growth
Development: Week 6
Eyes are present
Development: Week 7-8
All major organs are near completion EXCEPT for the respiratory system
Development: End of Week 8
Enters the phase of Fetal Development
Development: Week 9
Rapid growth and development of the GI tract
Development: Month 4
Skeletal Ossification
Development: Month 5
Movement, entire body is covered with lanugo (very fine hairs which protects from harsh amniotic fluid)
Development: Month 6
Cardiovascular System is mature enough to control beating, the CNS controls temperature
Development: Month 7
In boys, the testes descend
Development: Month 8
The lanugo is shed, and the Placenta blood vessels begin to deteriorate
Development: Month 9
Approximately 266 days after fertilization, the baby is born
Hormonal Regulation in Men
Spermatogenesis and Testosterone production involving the interactions between the hypothalamus, the anterior pituitary gland, and the testes
Sequence 1 in Male Hormone Regulation
In Males, this is the sequence where the Hypothalamus releases GnRH (Gonagotropin Releasing Hormone)
Sequence 2 in Male Hormone Regulation
In Males, this is the sequence where GnRH reaches the anterior pituitary glad, triggering the release of FSH and LH directly into the blood
Sequence 3 in Male Hormone Regulation
In Males, this is the sequence where FSH stimulates spermatogenesis INDIRECTLY by stimulating nurse cells to release androgen binding protein, ABP. FSH makes the cells receptive to the testosterone's stimulatory effect
Androgen Binding Protein
ABP, This prompts the spermatogenis cells to bind testosterone which in turn stimulates spermatogenesis.
Sequence 4 in Male Horomone Regulation
In Males, this is the sequence where LH binds to the interstital endocrinocytes, causing them to secrete testosterone.
Testosterone
The final trigger for spermatogenesis. Increased levels inhibit GnRH, FSH, and LH.
Inhibin
Produced by nurse cells, serves as a barometer for normal spermatogenesis.
Increased Inhibin Release
A result of an increased sperm count. This inhibits secretions by the anterior pituitary glands and the hypothalamus.
Decreased Inhibin Release
Happening dramatically, this is a reult of of a decreased sperm count (20 million/mL), allowing the anterior pituitary gland to secrete
Three Hormones affecting sperm and testosterone
GnRH, The Gonadotropins, testosterone, and inhibin, a balance of the three
Testosterone Functions
Includes Hair growth increase facial, pubic and body, and decrease on head. Hypertrophy of the laryngo mucosa (deep voice). Increased muscle mass from anabolic effect on protein, and increased bone mass and depostiton of calcium in the bone
Ovarian Cycle
Refers to the monthly sequence of events associated with maturation of an egg (28 days)
Lutenal Phase
Days 15 - 28 in the ovarian cycle. This phase is always 14 days from ovulation to the end of the cycle
Follicular Phase
Days 1 - 14 in the ovarian cycle. In women whose cycles are longer than 28 days, the length of this cylce and ovulation varies
Cyclic Changes
Changes occuring in the uterus at the same time of the events taking place in the ovary
Proliferative Phase
The phase the uterus goes through during the follicular phase in the ovary
Secretory Phase
The phase the uterus goes through during the luteal phase in the ovary
Oocyte Maturation
This maturation is timed by hormones initally released by the hypthalamus in a non pregnant state
Sequence 1 in Female Hormone Regulation
In Females, this is the sequence where the hypothalamus releases GnRH, causing the anterior pituitary gland to release FSH
Seqeunce 2 in Female Hormone Regulation
In Females, this seqeunce promotes maturation of several follicles in the ovary, each of which contains secondary Oocytes
Seqeunce 3 in Female Hormone Regulation
In Females, this sequence is when the follicles SNS estrogen, causing the lining of the uterus to proliferate (grow), increasing levels of estrogen and decreasing FSH release from the anterior pituitary gland
Sequence 4 in Female Hormone Regulation
In Females, this sequence results in increased levels of estrogen, causing a large release of LH from the anterior pituitary gland. This occurs around the end of day 13 or the beginning of day 14, causing ovulation to occur (the rupture and secondary release of Oocytes)
Corpus Luteum
(The yellow body) This is the remains of the follicle which stay on the surface of the ovary during ovulation. This secretes estrogen and progesterone
Estrogen
During ovulation, this hormone continues the growth of the endometrium
Progesterone
During ovulation, this hormone changes the endometrium to an actively secreting tissue in the Uterus
An Unfertilized Egg
This causes the Corpus Luteum to die after about 10 days, and estrogen and progesterone levels will drop
Decreased Estrogen and Progesterone
This causes the Stratum functionalis of the endometrium to break down, the myometerium will then begin to contact (Menstrual Cramping) and the straum functionalis will be expelled as menstrual flow. The anterior pituitary gland begins to secrete FSH and the cycle begins again
SNS of HCG
This is done by the Zygote and then the Placenta as soon as fertalization takes place. This Hormone keeps the corpus luteum alive and it continues to SNS estrogen and progesterone, which prevents menstruation
The Main Function of Estrogen
This is to promote cellular growth of all tissues associated with sexual organs related to reproduction. At Puberty, it causes rapid increase in osteoblastic activity, and rapid closing of epiphyseal plates
The Main function of Progesterone
This inhibits uterine contractions. If it were to decrease, then a woman would be unable to maintain a pregnancy