Introduction Flashcards
What are the tree subdisciplines of Embryology?
Descriptive
Comparative
Experimental
What is descriptive embryology
The study of the mechanisms of development
What are the two different periods that embryology can first be divided into?
Prenatal - before birth
Post natal- after birth
What are the two subdivisions of the prenatal period and how long are they?
Embryonic- 0-8 weeks
Fetal- 8 weeks to birth
The postnatal period can also be further divided into what five groups?
Infancy (neonatal period during the first 4 weeks) Childhood Puberty Adolescence Adulthood
In the post natal period how long do Infancy, childhood and Puberty last and what is the deciding factor that ends childhood?
Infancy- 0-1 year
Childhood- 1-13 years
Puberty 12-15 in girls and 13-16 in boys
Deciding factor in when childhood ends varies depending on when the child begins puberty
A division of the postnatal period, adolescence, is significant because this is where the individual gains what ability
The ability to reproduce
What does the term ventral mean?
Toward the belly
What does the term dorsal mean?
Toward the back
What does the term cranial mean?
Toward the head
What does the term caudal mean?
Toward the tail
What does the term rostral mean?
Toward the nose
What are the 4-5 sections called that can be made to study and embryo and what are their definitions?
Midsagittal- equal right and left halves
Sagittal- a section that yields right and left halves
Transverse (cross sectional)- top and bottom sections
Coronal (frontal)- yields front and back sections
Oblique- any section that is not cut on one of the three main planes of the body (X, Y, Z axes)
What is the primary sex organ of the male? And what is its function?
Testis
Where the sperm cells are developed and where testosterone is produced ( gamete production and hormone production)
What is are the two functions of the epididymis?
Storage of the sperm cells and activation of the sperm cells
What are the functions of the male reproductive system?
To produce and deliver the male gametes (sperm cells)
What are the 7 parts that make up the male reproductive system?
Testis Epididymis Ductus deferens Ejactulatory duct Urethra Prostate gland Seminal vesicles
What is the muscular tube that transports the sperm cells from the epididymis to the ejaculatory duct?
Ductus defrens
What is the function of the ductus defrens
Transports the sperm cells from the epididymis to the ejaculatory duct
What two parts of the male reproductive system run together to form the ejaculatory duct? And what is its function?
A short duct that formed from the union of the ductus defrens and the duct of the Seminal vesicle.
Empties into the prostatic urethra
The urethra of the male is divided into 3 sections. What are the three sections and where do they pass through?
Prostatic urethra: passes through the prostate gland.
Membranous urethra: passes through he pelvic diaphragm
Penile urethra: final section that passes through the penis
What represents the union of the reproductive and urinary systems in the male?
The prostatic urethra
Describe the seminal vesicles and where they are located.
Secretory glands that add an alkaline fluid tot he seminal fluid
Located on the posterior aspect of the urinary bladder
What is the function of the prostate gland and where is it located?
Located at the base of the urinary bladder
It adds fructose to the seminal fluid
What is the product of mitosis?
Two daughter cells identical to the parent cells
What is the product of meiosis?
Cells with half of the genetic material of the parents
What is the order of sperm production?
Spermatogonia (2n)-> primary spermatocyte (2n)-> secondary spermatocyte (1n)-> spermatid (1n)
What are large cells with a centrally placed nucleus found against the outer wall of the seminiferous tubules?
Spermatogonia
What are spermatogonia functions?
To make new spermatogonia (mitosis
Develop sperm cells (begin process of meiosis)
________ are mature sperm cells that enter the lumen of the seminiferous tubules
Spermatids
What are the stages of maturation from spermatids -> mature sperm?
Golgi phase
Acrosomal phase
Maturation phase
What happens in the golgi phase during the transformation of spermatids to mature sperm?
Golgi body forms the acrosomal vesicle and centrioles migrate toward the nucleus
What happens during the acrosomal stage during the transformation of spermatids to mature sperm?
Acrosomal vescile grows to cover the anterior half of the nucleus
Acrosome is critical for fertilization of egg
Nucleus becomes more condensed and the mitochondria condense around the forming flagellum
What happens during the maturation phase of the transformation of spermatids to mature sperm?
The residual cytoplasm is lost and the sperm cell is released into the tubercle
The head of the sperm is made up of the ______ and ______
The middle of the sperm is made up of ______ and ________
The tail of the sperm is made up of _______
Acrosome and nucleus
Mitochondria and flagellum
Flagellum
What makes the microtubules that form the flagellum?
Centrioles
What cell makes testosterone?
Leydig cell
What cell secretes the seminal fluid that supports the cells of sperm?
Sertoli cells
What secretes FSH and LH?
Anterior pituitary
What is the function of FSH in the male?
Stimulates seminiferous tubules to produce sperm cells
What does LH do in the male?
Stimulates the cells fo Leydig to produce testosterone
What controls the rate of sperm production to where if there are enough sperm produced, excess is no longer produced?
The hormone inhibin
What is the primary sex organ of the female?
Ovaries
What hormones are produced by the ovary?
Estrogen and progesterone
What are the 3 parts of the uterine tube?
Isthmus
Ampulla
Infundibulum
What is the function of the uterine tube?
Provides a passageway from ovary to the uterus for the egg cell and contains the site of fertilization
What part of the uterine tube is the site of fertilization?
Ampulla
The uterus is a muscular organ divided into what 4 parts?
Cervix, isthmus, body, and fundus
What are the layers of the wall of the uterus?
Endometrium
Myometrium
Perimetrium
What is the function of the endometrium?
Where the baby implants and it is the part that undergoes the monthly cycle
What is the function of the myometrium?
Smooth muscle layer that can stretch to accommodate pregnancy
What is the connective tissue covering the uterus called?
Perimetrium
The uterus is the site of __________ and where the _________ develops
Implantation and where the embryo develops
The endometrium is made up of what 3 layers?
Compact layer
Spongy layer
Basal layer
What makes up the functional layer of the endometrium?
Spongy and compact layers
These two are shed during the menstrual phase
Explain the menstrual phase of the uterine cycle
Day 1-5
Both estrogen and progesterone are at their lowest
Functional layer is lost during this phase
Explain the proliferative phase of the uterine cycle
Day 6-15
Estrogen levels increase
Functional layer is rebuilt
Explain the secretory phase
Day 15-27
Progesterone levels increase
Glands of the uterus begin to function and produce glycoproteins that coat the endometrium
Implantation occurs on day 21 of the cycle
Explain the ischemic phase of the uterine cycle
Day 28
Both progesterone and estrogen levels drop quickly resulting in the smooth muscle spasming in the functional layer
The spasm of the spiral arteries in the spongy layer results in the beginning of menstrual flow
What structure in the ovary are the eggs stored?
Egg nest
Explain the egg nest (hormone, make up, amount)
Made up of the egg cell and one layer of follicle cells
Under the influence of FSH
About 12 egg nests per month begin to develop primary follicles (marked by the development of 4 layers of follicle cells
The formation of ________ _______ begin via FSH resulting in 4 layers of follicle cells
Primary follicles
Explain secondary follicles
a fluid filled antrum that appears in about 6 follicles, as they develop more follicles, estrogen secretion increases
What makes up the mature follicle?
One large antrum, on day 14 the mature follicle ruptures resulting in ovulation
What is released from the mature follicle rupture?
Corona radiata
Egg+ zona pellucida and some layers of follicle cells
What hormone influences ovulation?
LH
The remaining cells that stay in the follicle swell and a small blood clot forms called the _______ _________
Corpus hemorrhagicans
As the follicle cell swells they secrete _______
If pregnancy occurs, they secrete it for 3 months
Progesterone
_________ cells make and secrete estrogen
Thecal cells
In the proliferative stage of the uterine cycle what hormones are prominent?
Estrogens being secreted from thecal cells
Secretory stage of the uterine cycle what hormone is prominent and where is it secreted from?
Progesterone and secreted from the follicle cells
What must occur in order for fertilization to occur (what must the sperm undergo in order to be able to fertilaize an egg)?
Capacitation
Only _______ sperm cells can pass through the corona radiata
Capacitated
Once the sperm cells have passed through the corona radiate, they must pass through the ________ _________
Zona pellucidum
What is the first stage of the process of penetrating the Zona pellucida (ZP)?
Attachment of the sperm to the ZP
Where does the attachment of the sperm to the ZP take place?
The ZP3 receptors
What are ZP3 receptors? And what from the sperm recognizes them?
Glycoproteins and recognized by bindin
What is bindin
A protein in the acrosome and egg binding protein
Explain the attachment phase
The sperm attaches to the ZP through binding to the ZP-3 receptors by the protein bindin that is located in the sperms acrosome
After attachment to the ZP, the sperm cells undergo _________ ______
Acrosomal reaction
What enzymes are in the acrosome that help penetrate the ZP?
Proteinase, glycosidase, phosphatase and phospholipase
During the acrosomal reaction, when the acrosomal enzymes are released it causes an influx of Na and Ca ions. What does the influx of these ions result in?
An efflux of Hydrogen ions which leads to an increase in the intracellular pH
The acrosomal reaction is dependent on what two things being present?
Calmodulin and ATP
With the release of enzymes plus the movement of ions in the acrosomal reaction, the _______ receptors convert to _______ receptors
ZP3
ZP2
What does the conversion of the ZP-3 receptors to ZP-2 receptors do?
Brings the inner wall of the acrosome to the zona pellucidum
And the release of acrosin enzyme
When does the sperm cell move across the ZP?
Once the ZP-3 receptor has been changed to ZP-2 and the release of the sperms acrosin
the _______ region of the cell fuses with the egg cell membrane
Posterior
What three events prevents polyspermy
Fast block (large depolarization) Slow block (cortical reaction) Zona reaction
Describe fast block to polyspermy
Depolarization of the membrane within 3 seconds of fertilization.
Na out and K in. The movement of the ions causes an electrical charge that stops all sperm movement for approx 1 min
Describe the cortical reaction
Cortical granules of the egg cell release hydrolytic enzymes that cause the inactivation of the ZP receptors and the hardening of the zona pellucidum
Explain the zona reaction
Any other ZP3 receptors on the ZP surface undergo change to become ZP3F receptors and cannot form any new attachements
And any ZP2 receptors undergo change to become ZP2F recprots to prevent any more penetration of sperm cells
What are the outcomes of fertilization?
Restoration of the 2n chromosome number
The determination of the sex of the individual
The initiation of cleavage division
The moment of fertilization when the two membranes fuse, the egg is called a ______
Zygote
At the 16 cell stage the dividing egg is referred to as a ______
Morula
At the _______ stage there is a solid ball of cells, the ZP is still intact and at this point diffusion of nutrients to the cell wil not be efficient
Morula (16 cell)
At what stage in cleavage division does one see differentiation of cells and the cells are no longer multipotential?
Blastocyst
When during cleavage division does the Zona pellucida disappear?
Late blastocyst stage
What cells secrete hCG?
Trophoblast cells
The blastocyst becomes polarized, what are the two poles called and what doe they consist of?
Animal pole- consists of the ICM
Vegetative pole- doesnt have the embryo, more of where the trophoblastic cells are
What are the three types of implantation?
Central
Eccentric
Interstitial
_________ implantation is where the zygote just attaches to the uterine wall
Central
_______ implantation is when the zygote partially enters the endometrium
Eccentric
What happens during the first phase of implantation?
The uterine smooth muscle contracts and slows down the embryo
The second stage of implantation is the ________ stage, when the embryo becomes trappe din the secretions of the uterine glands
Adhesive stage
The _____ phase and final phase of implantation is when the embryo begins to submerge into the endometrium of the uterus
Invasion phase
At the blastocyst stage its surrounded by a flattened layer of cells called the _______
Trophoblast
The trophoblast cells eventually form what?
The placenta
Also at the blastocyst stage the ICM is made up of cuboidal cells called the __________, these cells will form the developing embryo
Embryoblast
What cells differentiate into the bilaminar disk?
Embryoblast cells of the ICM
The bilaminar disk has an upper layer of cells called the ________ and a lower layer of cells called the ________
Epiblast
Hypoblast
During day 8 of devleopment the epiblastic layer undergoes mitosis and forms a fluid filled cavity called the _______
Amnion
What are the cells that line the amnion referred to as?
Amnioblast
During day 8 the hypoblast also undergoes mitosis and this mitosis gives rise to the ________ ________ that lines the primitive yolk sac
Exoceolomic membrane
The primitive yolk sac replaces the ________ as it develops
Blastocoel
The trophoblastic layer undergoes a mitosis to form two layers. What are they called?
The cytotrophoblast and the syncytiotrophoblast
What forms the extraembryonic mesoderm?
The cells that forms eh wall of the primitive yolk sac undergo mitosis and give rise to the new cells that are considered the extraembryonic mesoderm
The _______ _________ cells are found between the cytotrophoblast, the yolk sac and the amnion
Extraembryonic mesoderm
Syncytiotrophoblast cells conintue to grow and develop small cavities called ________
Lacunae
What establishes the utero-placental circulation?
Syncytiotrophoblast
The extraembryonic mesoderm splits into what two layers?
The extraembryonic somatopleuric mesoderm
The extraembryonic splanchnopleuric mesoderm
The cavity between the extraembryonic somatopleuric mesoderm and extraembryonic splanchnopleuric mesoderm is referred to as the _________
Chorion
What is the only area where this speration of the extraembryonic mesoderm has not occurred?
The connecting stalk
What eventually forms the umbilical cord?
The connecting stalk
What forms the primary villi?
The cytotrophoblast undergo mitosis to form the extensions called primary villi
The hypoblast undergoes another mitosis and forms a secondary yolk sac that replaces __________
The primary yolk sac
At the 2 week stage the bilaminar disk begins to change. The epiblast and hypoblast are still present but what changes occur in the hypoblast?
The hypoblast at one end of the embryo increases their height and form the prechordal plate
What marks the head-end of the embryo?
Prechordal plate
During ________ 3 germ layers are established
Gastrulation
What are the three germ layers established on week 3?
Endoderm
Ectoderm
Mesoderm
The process of gastrulation begins with the formation of the ___________
Primitive streak
The primitive streak has a _______ ______ at its cephalic end
Primitive node
the _____ ______ is a slightly raised area with a small primitive pit
Primitive node
Cells of the _______ layer migrate toward the primitive streak and invaginate
Epiblastic
The ectoderm is the old ______
The endoderm and mesoderm are the old _______
Epiblast
Hypoblast
Prenotochordal cells invaginate and move toward the prechordal plate, these cells from the ______ ______
Notochordal plate
The notochordal plate detaches from the endoderm and forms a solid chord of cells known as the _______
Definitive notochord
At the point where the primitive pit forms an indentation in the epiblast known as the _________
Neurenteric canal
The ______ ______ temporarily connects the amniotic and yolk sac cavities
Neurenteric canal
The ____ ______ is a muscular tube that transports the sperm cells from the epididymis to the ejaculatory duct
Ductus defrens
Where does the ductus defrens pass through?
From the epididymis through the spermatic cord, through the inguinal canal and to the posterior aspect of the urinary bladder. It then joins the duct of the seminal vesicle to form the ejaculaotry duct
The ______ ______ passes through the prostate gland to empty into the prostatic urethra
Ejaculatory duct
The urethra of the male may be divided into three sections. The _______ _______ passes through the prostate gland and represents the union of the reproductive and urinary systems in the male.
Prostatic urethra
The ________ urethra is the section that passes through the pelvic diaphragm.
Membranous
The ________ urethra is the final section is that part which passes through the penis.
Penile
Where are the seminal vesicles located and what is their function?
Secrete alkaline fluid to the seminal fluid
Located on the posterior aspect of the urinary bladder
Where is the prostate gland at and what is its function?
Located at the base of the urinary bladder
Adds fructose to the seminal fluid
Where are the sperm cells developed and where the hormone testosterone produced?
Testis
The ________ is locat4ed on the superior posterior aspect of the testis in the scrotum
Epididymis
On day 10 the _________ forms the utero-placental circulation with the maternal blood vessels
Syncytiotrophoblast
The intraembryonic mesoderm develops from the _______
Epiblast
Bottle cells would be found lining the ______ _____
Primitive node
The cloacal membrane is made up of what germ layers?
Ectoderm and endoderm
The process of hatching refers to what?
The removal of the zona pellucidum from the blastocyst
What does the intraembryonic mesoderm form from and what is it made up of and when is it formed?
Forms from the epiblast
Made up of mesenchyme cells
Formed by the process of gastrulation
The secondary yolk sac develops from the ________
Hypoblast
_______ ______ can trace the origin to the inner cell mass, embryoblast, ectoderm
Bottle cells
Cleavage division occurs in the __________
Uterine tube
The process of gastrulation is an example of what type of embryology?
Descriptive
What cells secrete progesterone?
Luteal cells
Which germ layer is in contact with the yolk sac?
Endoderm
Cleavage division does what 3 things?
Decreases cell size
Increases cell mobility
Divides the cytoplasm
What are the cells that directly cover the secondary yolk sac?
Extraembryonic splanchnopleuric mesoderm
What does the neurenteric canal connect?
The amnion and the yolk sac
The process of gastrulation describes the formation of the ________
Mesoderm
Hypoblast is renamed as the ______ in the trilaminar disc
Endoderm
