The Reproductive System

Question 1

What are the 2 kinds of reproduction? Describe them.

Answer 1

Asexual and sexual. Asexual involves one organism. It is the generation of new organisms without the sperm and the egg (dividing). Sexual involves 2 organisms. It is the fusion of the egg and sperm.

Question 2

What advantages and disadvantages do each have?

Answer 2

Asexual is bad because if an organism has a disorder, this will be passed down to the next generation and so on. But if the organism is healthy, then its offspring will thrive. The good thing about sexual reproduction is if the parent lives in an unstable environment, its offspring might have a better chance to live with the different traits from the 2 organisms. However, if the organisms are healthy, there is a chance that the traits together could create a disorder in the offspring.

Question 3

Why is it illegal to marry your near relatives?

Answer 3

Your relatives have similar traits and DNA as you do. The offspring are mostly guaranteed that they will have any disorder the parents have. If this continues throughout your line, it will increase disease throughout the world. This is what happened with the old royal families. They kept on marrying each other so a disease called hemophilia was passed down for generations until they finally started marrying other people. Then, it passed through other families and so on

Question 4

Where are the eggs made?

Answer 4

ovaries

Question 5

What do the eggs travel through to get to the uterus?

Answer 5

the oviduct or fallopian tube

Question 6

What are the two types of fertilization?

Answer 6

external and internal. external is the outside fusion of the egg and sperm. Internal is the inside fertilization of the egg and sperm (all mammals do internal)

Question 7

What is the corpus luteum?

Answer 7

part of ovaries, secretes estrogen and progesterone

Question 8

Describe the uterus.

Answer 8

VERY thick wall made of muscle to push future baby out (contractions).

Question 9

What is the endometrium?

Answer 9

the lining of the uterus. is let go every month if you’re not pregnant (called a period) bleeding out vagina

Question 10

What is the cervix?

Answer 10

the mouth of uterus (opening) when it opens, its called dilating

Question 11

What is a hysterectomy?

Answer 11

when the uterus is removed (usually after child bearing if you’re having extra bleeding)

Question 12

What types of cancer could only girls develop? Guys?

Answer 12

ovary cancer and/or cervical cancer, prostate cancer

Question 13

Where are the sperms first made?

Answer 13

the testis - on outside because the sperm requires colder temperature than body temperature (2 degrees C lower)

Question 14

Describe the path the sperm takes

Answer 14

testes, epididymus, vas deferens, scrotum, seminal vesicle behind bladder, prostrate gland, bulbourethral gland, urethra surrounded by erectile tissue

Question 15

Describe the epididymis

Answer 15

sperm gains motility; matures

Question 16

vas deferens

Answer 16

passing through

Question 17

scrotum

Answer 17

tube leading to seminal vesicle

Question 18

seminal vesicle

Answer 18

where the sperm mixes with other substances to make semen: sugar/fructose for energy on the journey, mucus for protection, enzymes, and escorbic acid (Vitamin C)

Question 19

prostate gland

Answer 19

secretes enzymes and citrate - put into urethra

Question 20

bulbourethral gland

Answer 20

secretes mucus so it neutralizes the acid from the leftover urine

Question 21

vasectomy

Answer 21

vas deferens is removed

Question 22

Describe the menstrual cycle.

Answer 22

The hypothalamus releases GnRH to stimulate the anterior pituitary gland to release FSH (follicle stimulating hormone) and leutenizing hormone (LH). These stimulate follicle growth. The follicles secrete estragen which goes back to the brain (hypothalamus and the pituitary gland). This causes an LH surge which then causes ovulation (the egg released from the ovary). The corpus luteum (what’s left over from the ovary) secretes estragen and progesterone. These inhibit FSH and LH from being made in the brain. This promotes the thickening of the endometrium. The corpus luteum disintegrates so the blood vessels constrict which deprives the uterus tissues of blood (oxygen and nutrients) so they die. The lining is then shed creating a period.

Question 23

What happens if the egg is fertilized?

Answer 23

The egg is released from the oviduct (ovulation), and the sperm enters the vagina and starts to swim up until it gets to the oviduct. Fertilization occurs. It only occurs in the oviduct in a specific slot of a few hours. One sperm attaches to the egg. It has 2 reactions: the acrosomal and cortical reaction (see other q). This develops the zygot (the fertilized egg with 46 chromosomes). Cell division happens within the first 24 hours (called cleavage). This continues until the egg is a ball of 16 cells, called a blastocyst. The blastocyst implants itself on the uterus wall after it exits the oviduct about a week after fertilization. The part that goes into the endometrium is the trophoblast which later develops into the placenta and the umbilical cord. The placenta is the baby’s lifeline to its mother. It (and the umbilical cord) is made up of blood vessels that carry oxygen and nutrients to the baby (so that it may perform cellular respiration) while getting rid of the waste materials. After this, a hormone called hCG is released. Its job is to make sure the corpus luteum keeps making progesterone and estragen so that the endometrium or the lining is not released during the pregnancy. A pregnancy has 3 trimesters. In the first, the baby develops all its organs (brain, digestive, heart, etc.) In the second trimester, the baby grows mostly. The placenta takes over the control of estragen and progesterone, and the woman can feel the baby after about 4 months. The 3rd trimester is dedicated to growing. The baby is then ready to give birth between 37 weeks and 42 weeks.

Question 24

Explain labor and how it is an example of positive feedback.

Answer 24

Estradiol is secreted from the ovaries and activates oxytocin receptors on the uterus so that oxytocin is released from the posterior pituitary gland. Oxytocin causes the mother to have contractions. The contractions cause more oxytocin to be released which of course causes more contractions. This is an example of positive feedback - it’s a cycle that is produced more and more once it’s done the first time. The three stages of labor are the dilation (opening) of the cervix, expulsion (delivery of the infant), and the delivery of the placenta.

Question 25

What are the acrosomal and the cortical reactions?

Answer 25

The acrosomal reaction is when the sperm releases enzymes to eat away the outside of the egg to fertilize it. The cortical reaction is when the fertilization envelope is developed so no other sperm can fertilize that one egg.

Question 26

What is menopause?

Answer 26

when women begin to stop having periods around 50-ish. They are less responsive to hormones, so they begin to have irregular periods (like when they first started) and not have them any more.

Question 27

How are pregnancy tests conducted?

Answer 27

They test the hCG levels in a woman’s urine because when the blood (carries hormones) goes through the kidneys, the hCG is so small and plentiful that it is filtered through the glomerulus and is not reabsorbed in the nephron.

Question 28

What is a miscarriage?

Answer 28

many reasons: not enough hormones are made, placenta detaches, etc.

Question 29

What is gastrulation?

Answer 29

Gastrulation occurs during the 1st trimester. When the blastocyst is embedded in the endometrium, it develops three layers. There is the ectoderm (nervous system, teeth, skin), mesoderm (muscles, bones, blood, heart), and endoderm (digestive/respiratory system). And then after this, the blastocyst goes through organogenesis, which is when the organs fully develop