Transcript Chapter 51
Chapter 51 Reproductive System
Table of Contents
Section 1
Male Reproductive System
Section 2
Female Reproductive System
Section 3
Gestation
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Chapter 51 Section 1 Male Reproductive System
Objectives
•
Identify
the major structures of the male reproductive system.
•
Describe
the function of each structure of the male reproductive system.
•
Relate
the structure of a human sperm cell to its function.
•
Trace
the path that sperm follow in leaving the body.
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Chapter 51
Male Reproductive Structures
• The male reproductive system contains two testes. – The
testes
are the gamete producing organs of the male reproductive system.
– **Testes contain seminiferous tubules – **Scrotum houses the testis, & is lower in temperature than in the abdomen
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Chapter 51 Section 1 Male Reproductive System
Male Reproductive Structures, continued
• Each testis is made up of the epididymis and the seminiferous tubules.
– The
epididymis
is a long, coiled tubule that is closely attached to – each testis.
**Epididymis
maturation is the site of sperm – The
seminiferous tubules
are tightly coiled tubules where sperm form through meiosis.
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Chapter 51 Section 1 Male Reproductive System
Formation of Sperm
• At puberty, sperm form through meiosis.
• Sperm contain a **head, a midpiece, and a tail.
– The **head contains the enzymes and chromosomes (DNA) that will be delivered to the egg.
– The midpiece’s mitochondria power the movement of the tail.
– **Flagellum is the sperms tail
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Chapter 51 Section 1 Male Reproductive System
Formation of Sperm, continued
•
Path of Sperm Through the Male Body
– The path of the sperm through the body begins as the sperm move from the seminiferous tubules to the epididymis.
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Chapter 51 Section 1 Male Reproductive System
Formation of Sperm, continued
• Path of Sperm Through the Male Body, continued – From the epididymis, sperm move into the vas deferens.
• The
** vas deferens
is a duct that extends from the epididymis to the urethra. This duct is made of smooth muscle and helps sperm exit the body.
– From the vas deferens, sperm move to the urethra.
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Chapter 51 Section 1 Male Reproductive System
Formation of Sperm, continued
• Path of Sperm Through the Male Body, continued – Once in the urethra, the sperm will mix with other fluids produced by the seminal vesicles, the prostate gland, and the bulbourethral glands. • The
seminal vesicles
lie between the bladder and the rectum and produce a fluid that sperm use for energy.
• The
** prostate gland
is located just below the bladder and produces a fluid that neutralizes the acids in the
female
reproductive system.
• The
** bulbourethral glands
produce a fluid that neutralizes any acidic urine left in the
urethra
.
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Chapter 51 Section 1 Male Reproductive System Male Reproductive System
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 51 Section 1 Male Reproductive System
Formation of Sperm, continued
•
Delivery of Sperm
– Fluids that are excreted from glands within the penis are mixed with the sperm to produce
semen.
– **The secretions of the prostate gland contribute to the production of sperm – After passing through the urethra, the semen will exit the body through the penis.
• The
penis
is the organ that deposits sperm in the female reproductive system.
–
Ejaculation
is the process in which semen is forcefully expelled from the penis by contractions of the smooth muscles that line the urethra.
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Chapter 51 Section 2 Female Reproductive System
Objectives
•
Identify
the major structures of the female reproductive system.
•
Describe
the function of each structure of the female reproductive system.
•
Describe
how eggs are produced.
•
Summarize
the stages of the ovarian cycle.
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Chapter 51 Section 2 Female Reproductive System
Female Reproductive Structures
• The female reproductive system contains two ovaries, two fallopian tubes, and a uterus.
• **The ovary secrets estrogen in response to LH stimulation
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Chapter 51 Section 2 Female Reproductive System
Female Reproductive Structures, continued
• The
ovaries
are the gamete-producing organs of the female reproductive system.
• The
fallopian tubes,
also called the uterine tubes, are made of smooth muscle and join the ovary to the uterus.
•
**Fallopian tube
is the site of fertilization • The
uterus
is a hollow, muscular organ about the size of a small fist and is the place where the fertilized egg will develop.
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Chapter 51 Section 2 Female Reproductive System Female Reproductive System
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Chapter 51 Section 2 Female Reproductive System
Female Reproductive Structures, continued
• The lower entrance of the uterus is the cervix, which leads to the female reproductive opening called the vagina.
– The
**vagina
is a muscular tube that leads to the outside of the body. The vagina receives ejaculated sperm from the penis, and it is also the channel through which a baby passes during childbirth.
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Chapter 51 Section 2 Female Reproductive System
Formation of Eggs
• Unlike males, a female is born with all the eggs she will ever produce. • These immature eggs will be stimulated to mature starting at puberty. A hormone will stimulate a batch of eggs to continue to mature about every 28 days.
• However, an egg will not complete maturation until fertilized by a sperm. • If fertilized, the mature egg, or
ovum,
will continue development as it travels through the fallopian tube.
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Chapter 51 Section 2 Female Reproductive System
Preparation for Pregnancy
• The female reproductive system will prepare and release an ovum each month in a process called the
ovarian cycle,
which is controlled by the endocrine system.
• The ovarian cycle has 3 phases: the follicular phase, ovulation, and the luteal phase.
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Chapter 51 Section 2 Female Reproductive System
Preparation for Pregnancy, continued
•
Follicular Phase
– The
follicular phase
is when the immature egg will complete its first meiotic division. This phase begins because it is stimulated by the follicle stimulating hormone (FSH). • FSH will stimulate the egg to mature by stimulating the
** follicle,
or layer of cells that surrounds an immature egg, to divide.
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Chapter 51 Section 2 Female Reproductive System
Preparation for Pregnancy, continued
•
Ovulation
–
Ovulation
follicle. is when an egg is released by the
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Chapter 51 Section 2 Female Reproductive System
Preparation for Pregnancy, continued
•
**Luteal Phase
– During the luteal phase, the cells of the ruptured follicle grow larger and create a new structure called a
corpus luteum.
1. If the egg is not fertilized, this phase will end
with menstruation
2. Uterine lining sloughs off 3. FSH levels can begin to rise
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Chapter 51 Section 2 Female Reproductive System
Preparation for Pregnancy, continued
•
Menstruation
–
Menstruation
is when the lining of the uterus and blood from ruptured blood vessels are discharged through the vagina.
• This process can last about 5 to 7 days until a woman reaches menopause.
–
Menopause
is when most of a woman’s follicles have either matured and ruptured or degenerated. Thus, menstruation ceases.
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Section 3 Gestation Chapter 51
Objectives
•
Sequence
the events of fertilization, cleavage, and implantation.
•
Describe
the three stages of pregnancy.
•
Summarize
pregnancy. the development of an embryo during •
Discuss
the effects of unnecessary drug use on development.
•
Describe
birth.
the changes in a mother’s body during
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Section 3 Gestation Chapter 51
Fertilization
• If sperm are ejaculated into a female within 48 to 72 hours of ovulation, the chances of those sperm finding and fertilizing and egg are likely.
• Once any sperm encounters an egg, it will try to penetrate its outer layers, but usually only one sperm is successful in fertilizing the egg.
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Section 3 Gestation Chapter 51
Fertilization, continued
• When fertilization occurs, the egg and sperm fuse to form a zygote.
– A
zygote
is the diploid cell that results when the egg and sperm fuse together.
– **Both egg and sperm have the haploid (1n) number of chromosomes • The period of development from fertilization of the egg through the next **nine months is known as
gestation.
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Section 3 Gestation Chapter 51 Early Zygote Development
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Section 3 Gestation Chapter 51
•
Fertilization, continued
Cleavage and Implantation
– Once the egg is fertilized, the zygote will begin a series of mitotic divisions known as cleavage. – **Transformation of a zygote to a blastocyst requires cl
eavage
– **The male reproductive organ that has similar functions to those of an ovary is the testis
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Section 3 Gestation Chapter 51
Fertilization, continued
•
Cleavage and Implantation
– The morula has become a blastocyst by the time it reaches the uterus.
– Once at the uterus, the blastocyst releases an enzyme that allows it to burrow into the thickened walls of the uterine lining. This process is called
implantation.
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Section 3 Gestation Chapter 51
Pregnancy
• The **nine-month period of growth and development that a blastocyst undergoes is called gestation or
pregnancy.
• Pregnancy is divided into three equal periods called
trimesters,
and each trimester is signaled by specific events.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
First Trimester
– During the first eight weeks of pregnancy, the developing human is called an
embryo.
– The embryo during this phase looks much like all other developing animal embryos, but it will soon reorganize into the primary germ layers: the endoderm, mesoderm, and ectoderm.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
First Trimester
– During the first trimester, four membranes form that will be essential in the development of the embryo.
– One membrane is called the
amnion
the
amniotic sac,
and forms which keeps the embryo moist and protected by surrounding the developing embryo.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
**First Trimester
– The second membrane is called the
yolk sac
, which is where the first blood cells will originate from. – The third membrane is called the
allantois chorion
.
– The fourth membrane is called the
chorion
, which surrounds all other membranes and forms the chorionic villi. • The
chorionic villi
are finger like projections that will attach and extend into the uterine lining.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
First Trimester
– The chorionic villi and part of the uterine lining will form the placenta. The
** placenta
is the structure through which the mother nourishes the embryo (passes nutrients from mother to fetus) – The placenta connects the mother to the embryo by way of the umbilical cord. The
umbilical cord
allows substances to exchange between mother and embryo by way of diffusion.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
First Trimester
– From eight weeks until birth, the developing child is called a
fetus.
– At the end of the first trimester, all of the organs of the fetus have begun to form.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
Second Trimester
– During the second trimester, the heartbeat of the fetus can be heard, its skeleton begins to form, and it begins to develop body fat.
– The baby has a layer of soft hair called
lanugo
growing over its skin.
– The baby begins to move, sleep, and wake.
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Section 3 Gestation Chapter 51
Pregnancy, continued
•
Third Trimester
– During the third trimester, the baby undergoes changes that will enable it to live outside the mother.
– It also develops fat deposits under its skin to insulate its body.
• These fat deposits also make the fetus look more rounded and less wrinkled.
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Section 3 Gestation Chapter 51
Birth
• In reaction to hormones produced by both the fetus and the mother, childbirth is initiated.
• During childbirth, the smooth muscles of the uterus begin to contract and the muscles in the vagina and cervix relax and enlarge, which allow the fetus to pass through.
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Section 3 Gestation Chapter 51
Birth, continued
• • The process of muscle contractions and other related events that lead up to childbirth are called
labor.
**Labor
is the process in which the fetus leaves the mother’s body • After the fetus has been pushed through the vagina, contractions of the uterus help the mother expel the **placenta, amnion, and uterine lining. This group of membranes is called the
afterbirth.
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Chapter 51 Standardized Test Prep
Multiple Choice
1. Which of the following is the correct pathway for sperm as it exits the body?
A. the testes to the penis to the epididymis B. the urethra to the vas deferens to the testes C. the epididymis to the vas deferens to the urethra D. the testes to the vas deferens to the epididymis
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
1. Which of the following is the correct pathway for sperm as it exits the body?
A. the testes to the penis to the epididymis B. the urethra to the vas deferens to the testes C. the epididymis to the vas deferens to the urethra D. the testes to the vas deferens to the epididymis
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
2. Which of the following is true about follicle-stimulating hormone?
F. It is secreted by the follicle.
G. It is secreted by the pituitary gland.
H. It promotes contractions of the uterus.
J. It stimulates the development of the placenta.
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
2. Which of the following is true about follicle-stimulating hormone?
F. It is secreted by the follicle.
G. It is secreted by the pituitary gland.
H. It promotes contractions of the uterus.
J. It stimulates the development of the placenta.
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
3. Which of the following help form the placenta and umbilical cord?
A. the amnion and chorion B. the amnion and yolk sac C. the chorion and yolk sac D. the chorion and allantois
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
3. Which of the following help form the placenta and umbilical cord?
A. the amnion and chorion B. the amnion and yolk sac C. the chorion and yolk sac D. the chorion and allantois
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
4. By the end of the first trimester, which of following has occurred in the fetus?
F. The fetus has a full head of hair.
G. The fetus uses its lungs to breathe.
H. The brain of the fetus is fully developed.
J. All of the organs of the fetus have begun to form.
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
4. By the end of the first trimester, which of following has occurred in the fetus?
F. The fetus has a full head of hair.
G. The fetus uses its lungs to breathe.
H. The brain of the fetus is fully developed.
J. All of the organs of the fetus have begun to form.
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
Use the figure below to answer questions 5 –6. The figure shows the image of a sperm cell.
5. Where are the enzymes that help the sperm penetrate the ovum found?
A. in the head B. in the nucleus C. in the midpiece D. in the flagellum
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
Use the figure below to answer questions 5 –6. The figure shows the image of a sperm cell.
5. Where are the enzymes that help the sperm penetrate the ovum found?
A. in the head B. in the nucleus C. in the midpiece D. in the flagellum
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
Use the figure below to answer questions 5 –6. The figure shows the image of a sperm cell.
6. Where are the mitochondria that supply the energy that sperm need for movement?
F. in the head G. in the nucleus H. in the midpiece J. in the flagellum
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
Use the figure below to answer questions 5 –6. The figure shows the image of a sperm cell.
6. Where are the mitochondria that supply the energy that sperm need for movement?
F. in the head G. in the nucleus H. in the midpiece J. in the flagellum
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
7. testis : ovary :: vas deferens : A. sperm B. urethra C. fallopian tube D. prostate gland
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
7. testis : ovary :: vas deferens : A. sperm B. urethra C. fallopian tube D. prostate gland
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
Use the figure below to answer question 8. The figure shows the image of a an ovary.
8. What event is illustrated by this figure? F. ovulation G. ejaculation H. fertilization J. menstruation
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Chapter 51 Standardized Test Prep
Multiple Choice, continued
Use the figure below to answer question 8. The figure shows the image of a an ovary.
8. What event is illustrated by this figure? F. ovulation G. ejaculation H. fertilization J. menstruation
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Chapter 51 Standardized Test Prep
Short Response
Sperm are able to survive for around 48 hours in a female even though they have very little cytoplasm to provide nutrients. Explain why you think sperm can survive with few nutrients.
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Chapter 51 Standardized Test Prep
Short Response, continued
Sperm are able to survive for around 48 hours in a female even though they have very little cytoplasm to provide nutrients. Explain why you think sperm can survive with few nutrients.
Answer:
The seminal fluids secreted by exocrine glands nourish and protect the sperm.
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Chapter 51 Standardized Test Prep
Extended Response
Base your answers to parts A & B on the information below.
During the 1950s, a number of women were prescribed thalidomide, a drug to relieve morning sickness. These women gave birth to babies with serious limb defects. Scientists later discovered that thalidomide caused limb defects in fetuses.
Part A Do you think it is safe for a woman to take thalidomide during her first and second trimesters of pregnancy? Explain your answer.
Part B Do you think it is safe for a woman to take thalidomide during the third trimester of her pregnancy? Explain your answer.
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Chapter 51 Standardized Test Prep
Extended Response, continued
Answer:
Part A
It is not safe because the drug can cause limb deformations and the fetus’s limbs are forming during these trimesters.
Part B
It is probably safer for the woman to take this drug during this trimester than the first and second trimester because the drug’s only known side effect is limb deformation and the fetus’s limbs would have already formed by the third trimester. However, women should avoid taking any drugs during pregnancy without consulting a doctor.
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