Unit B/C1 Test: Reproduction & Development/Cell Division

Question 1

What is present in semen?

Answer 1

-Sperm: Male gonads
-Fructose solution: secreted from the seminal vesicles to nourish sperm
-Alkaline buffer: secreted from the prostate to protect sperm from the acidic vagina
-mucous fluid: secreted from Cowpers gland prior to ejaculation to clear urethra

Question 2

What produces each part of the semen

Answer 2

-Cowpers gland: mucous
-Prostate: alkaline buffer
-Seminal vesicles: Fructose solution/ prostaglandin(stimulates uterine contractions O
-Testes: sperm

Question 3

What are the four phases of the menstrual cycle?

Answer 3

-Flow phase: the beginning of the cycle, shedding of the endometrium lining(menstruation), progesterone/estrogen levels are low.
-Follicular phase: FSH stimulates the development of the follicle, Development of follicles within the ovary, follicle will secret estrogen
-ovulatory phase: LH will stimulate ovulation, secondary oocyte bursts from the ovary and follicular cell will become the corpus luteum, estrogen levels will drop
-luteal phase: corpus luteum forms and the endometrium lining thickens, corpus luteum secretes progestrone and estrogen, if fertilization does not occur the corpus luteum will disolve and the cycle will repeat

Question 4

What days correspond to the four phases?

Answer 4

Days 1-5: Flow phase
Days 6-13: folicular phase
Day 14: Ovulatory phase
Day 15-28: Luteal Phase

Question 5

What are the hormones doing in each of the four phases?

Answer 5

-Flow phase: low progesterone and estrogen levels signal the brain to secrete FSH and begin menstruation
-Folicular phase: FSH causes follicle to develop and secrete estrogen, estrogen will cause a decrease in LH and FSH levels until days 10-12 when it will cause LH and FSH production to ramp up (positive feedback)
-Ovulatory phase: A spike in LH will cause ovulation, follicle will no longer secrete estrogen so estrogen levels will drop
-Luteal phase: Corpus luteum will secrete progesterone and estrogen, causing those levels to rise

Question 6

What are the male hormones and where are they secreted from? What is the function of these hormones and where do they target?

Answer 6

-Testosterone: Produced in the interstitial cells of the testes, targets most cells, responsible for stimulating spermatogenesis, causing muscle growth, increasing sex drive, and developing male secondary sex characteristics
-FSH: produced by the pituitary, targets the testes, stimulates the sertoli cells in the testes to help produce sperm in the seminiferous tubules
-LH: produced by the pituitary, targets the testes, stimulates the production of testosterone in the interstitial cells of the testes

Question 7

What is the function of the placenta?

Answer 7

-Act as the lungs, kidneys and small intestine of the fetus. This is done via diffusion of important nutrients and gasses, along with wastes, from the maternal to the fetal blood across the placenta

Question 8

What is the function of the amniotic sac?

Answer 8

Fluid filled sac that insulates and protects the developing fetus

Question 9

What is the function of the umbilical cord?

Answer 9

allows the difusion between the meternal blood and fetal blood to take place

Question 10

What is the general order of events in fetal development?

Answer 10

fertilization - zygote -3 to 6 days- blastocyst - implantation - gastrulation - embryonic development - Formation of Amnion, Chorion layers, yolk sac, and allantois - formation of placenta and umbilical cord - fetal development(CNS, Heart, Limbs, Ear, eyes, palet, teeth, genitals

Question 11

What is the function of the chorion layer, and what two hormones does it secrete?

Answer 11

The chorion layer secretes HGC which supports the corpous luteum until the placenta developes. this keeps progestrone levels high

Question 12

What two hormones does the placenta secrete and why?

Answer 12

The placenta secretes progestrone and estrogen to prevent uterine contractions and keeping the pregnancy

Question 13

What do the two rounds of meiosis do?

Answer 13

Round 1: This is considered a reduction division because during this stage the chromosome number is halved (2n-46)-(2n=23)

Round 2: This round is considered and equational division because the chromosome number dose not change. This stage serves to separate the sister chromitids of the daughter cells in phase one so that final products are single stranded (2n=23)-(n=23)

Question 14

What is produced from the ectoderm?

Answer 14

Skin, Hair, fingernails, sweat glands, nervous system, brain, lens, retina, cornea, inner ear, cochlea, semi-circular canals, teeth, inner lining of mouth

Question 15

what is produced from the endoderm?

Answer 15

Liver, pancreas, thyroid, parathyroid, bladder, lining of digestive system, lining of respiratory system

Question 16

what is produced from the mesoderm?

Answer 16

Muscles, blood vessels and blood, kidneys and reproductive structures, connective tissues, cartilage, bones

Question 17

Ploidy: if a cell is 2n=98 n=?

Answer 17

49

Question 18

Ploidy: if a cell is 8n=288 n=?

Answer 18

36

Question 19

Ploidy: if a cell is 17n=1411 n=?

Answer 19

83

Question 20

When a zygote turns into a blastocyst, what type of cell division is used?

Answer 20

Mitosis

Question 21

What is a teratogen, and when do they have the biggest impact? What causes teratogens (environmental or genetic factors)?

Answer 21

A teratogen is a agent that produces malformations in a fetus. their destructive power is directly related to the critical growth periods of the fetus. they can be both environmental and genetic and include thing like: german mesales, drug/alcohol use, hypertension and manny more

Question 22

What are the female hormones, what are their functions?

Answer 22

-Estrogen: produced in the follical of the overies, targets most cells, initiates secondary sex characteristics in females at the start of puberty, Thickens/develops the endometrium lining.
-Progestrone: produced by the corpus luteum, targets most cells, firms the cervix, prevents ovulation, prevents uterine contractions
-FSH: produced by the pituitary, targets the follical, stimulates the follical to develop in the ovary
LH: produced by the pituitary, targets ovaries, stimulates ovulation, maintains the corpus luteum

Question 23

How do you identify sex on a karyotype? Nondisjunction? trisomy or monosomy?

Answer 23

To identify sex, you must look at the x and y chromosomes; if there are 2 x chromosomes the person is female, if there’s an x and a y they are male. To identify nondisjunction, look at all the chromosome pairs, if any have an extra trisomy has occurred, if any are missing monosomy has occurred

Question 24

What are the general phases of meiosis and mitosis?

Answer 24

IP-MAT

Interphase, protophase, metaphase, anaphase, telophase, cyotokinisis

(miosis will have I or II following the phase

Question 25

What is spermatogenesis

Answer 25

A process in which sperm develop from a diploid germ cell (2n=46) in the seminiferous tubules of the testes. beginning with a primary spermatocyte that will go through two rounds of meiosis to produce four haploid daughter cells (spermatids) which will continue to develop

Question 26

what is oogenesis

Answer 26

A process in which a germ cell called a primary oocyte will go through two rounds of meiosis. this will produce four haploid daughter cells(n=23)- one egg and three polar bodies

Question 27

What are the differences between spermatogenesis and oogenesis

Answer 27

-Spermatogenesis is the formation of sperm where oogenesis is the formation of the ova
-Spermatogenesis occurs in the testes where oogenesis occurs in the ovaries
-Spermatogenesis is a continuous processes, oogenesis is a finite process
-Spermatogenesis produces mobile gamates, oogenesis dose not
-Spermatogenesis divides cytoplasm equally, oogenesis dose not

Question 28

What are the female sex organs and their functions

Answer 28

-Ovary’s: Secrete hormones, protect and release eggs
-Fallopian tubes: connect ovaries to the uterus, site of fertilisation, fertilised eggs pass to the uterus
-Uterus: Hollow muscular organ located between the bladder and rectum, Fertilised eggs attach to the lining of the uterus
-Endometrium: Inner most lining of the uterus, Shedding of this lining happens during the menstrual cycle, site of implantation
-Cervix: cylinder shaped neck of tissue that connects the vagina to the uterus
-Vagina: Connects the uterus to the outside of the body

Question 29

What path does semen leave the body?

Answer 29

1.Testes/epididymis
2. Vas deferens: carries sperm from testes to ejaculatory duct
3. Seminal vesicles: secrete fructose solution into semen
4. prostate: secretes alkaline buffer
5. Ejaculatory duct
6. Urethra

Question 30

What diffuses from the maternal blood to the fetal blood across the placenta

Answer 30

Vital gasses: Mother to fetus/fetus to mother
Waste materials: Fetus to mother
Nutrients: Mother to fetus

Question 31

What hormones are involved in birth, what are their functions?

Answer 31

Oxycontin: stimulates uterine contractions
relaxin: relaxation of the pelvic ligaments allowing the cervix to widen/dilate

Question 32

What are the general steps of IVF

Answer 32

1. Egg production stimulated by hormone therapy
2. eggs retrieved from ovary
3. sperm sample provided
4. Eggs and sperm combine to allow fertilisation
5. fertilised eggs introduced into the uterus

Question 33

How dose nondisjunction occur?

Answer 33

Nondisjunction occurs when two homologous chromosomes move to the same pole during anaphase I or when two sister chromaitids move to the same pole in anaphase II