A&P CH 26/27

Define homozygous and heterozygous. (Module 27.15A)

Homozygous means that homologous chromosomes carry the same allele of a given gene. Heterozygous means that homologous chromosomes carry different alleles of a given gene.

The gradual modification of anatomical structures during the period from conception to maturity is

development.

The stage of labor during which the fetus emerges from the vagina is called the ________ stage.

expulsion

A zygote whose genotype is XX will develop as a

female

The period of gestation when the rudiments of all major organ systems are established is the ________ trimester.

first

An individual who expresses a recessive phenotype must have what genotype?

homozygous recessive

A zygote whose genotype is XY will develop as a

male

The special type of cell division required to produce gametes is called

meiosis.

After fertilization, the first cell division is completed

more than a day later.

Which hormone stimulates the milk let-down reflex?

oxytocin

The breasts are attached to the chest superficial to the ________ muscle.

pectoralis major

The ________ is a layer of smooth muscle in the skin of the scrotal sac.

dartos muscle

Which of the following is a barrier method of birth control?

diaphragm

The first stage of labor is the ________ stage.

dilation

Name the structures of the male internal genitalia. (Module 26.1C)

ductus deferens, seminal gland, prostate, bulbo-urethral gland, epididymis, testis

The organ that carries sperm from the epididymis to the urethra is the

ductus deferens.

A child born with one lone X chromosome will have

Turner's syndrome.

Define vasectomy. (Module 26.16C)

Vasectomy is the surgical sterilization of males by cutting the ductus deferens.

The main portion of the uterus is called the

body

Which of the following muscles move the testes towards the body?

both the cremaster and the dartos

Endoderm + mesoderm = which extra-embryonic membrane(s)?

both yolk sac and allantois

The ________ is the inner lining of the uterus.

endometrium

The inner cell mass of the blastocyst will

form the embryo.

The external marking of the boundary between the two testes is the

raphe.

The cells that are formed during spermatogenesis by the first meiosis are called

secondary spermatocytes.

Within which structure does sperm production occur?

seminiferous tubule

Sperm production occurs in the

seminiferous tubules.

Sperm develop from stem cells called

spermatogonia.

The process of spermiogenesis produces

spermatozoa.

Which is an example of codominance of inheritance?

structure of albumins

The mesoderm forms

muscle.

The ectoderm forms

neural tissues

Name the structures of the male external genitalia. (Module 26.1B)

penis, urethra, and scrotum

The ________ is the outer lining of the uterus.

perimetrium

What roles do the ovaries perform? (Module 26.9B)

produce oocytes, secrete female sex hormones, secrete inhibin

Each of the following statements concerning development is true except

the first trimester is when the fetus first looks distinctively human.

The embryonic heart starts beating as blood begins to flow through chorionic vessels at approximately ________ of development.

week 3

Name the four extra-embryonic membranes. (Module 27.5A)

yolk sac, amnion, allantois, and the chorion

In a spermatozoan, activity in the ________ provides energy required to move the tail.

mitochondria

After 3 days, a pre-embryo becomes a solid ball of cells known as a

morula.

The thick muscular layer of the uterus is the

myometrium

Which of the following does not occur during the first trimester?

organs become functional

Sperm are moved along the ductus deferens by

peristaltic contractions.

The traits of an individual controlled by his or her genotype are his or her

phenotype.

The placenta is expelled from the uterus during the ________ stage of labor.

placental

The ________ is a fleshy pouch suspended below the perineum and anterior to the anus.

scrotum

Fertilization of an ovum usually takes place in the

uterine tube.

The structure that transports the ovum to the uterus is the

uterine tube.

There are three alleles that determine blood type. IA and IB are codominant, and i is recessive to both of them. Serina has Type B blood. Which of the following might be Serina's genotype?

IBIB or IBi

Identify the sources of hormones that control male sexual and reproductive functions. (Module 26.7B)

hypothalamus, anterior lobe of the pituitary gland, and the testes

Attachment to and penetration of the endometrium by the blastocyst is referred to as

implantation

Molly is homozygous for the dominant black hair trait. Therefore,

Molly has black hair.

Contractions of the bulbospongiosus muscles result in

ejaculation.

Spermatozoa functionally mature within the

epididymis.

The onset of the first uterine cycle is called

menarche

The average length of the uterine cycle is

28 days

The infancy stage of life is considered to be over when the baby reaches ________ of age.

1 year

How long does each menstruation typically last? (Module 26.12B)

1-7 days

What is the proper arrangement of the four structures listed below into the order in which sperm pass from the testis to the urethral meatus? 1. ductus deferens 2. urethra 3. ejaculatory duct 4. epididymis

4, 1, 3, 2

How many chromosomes are contained within a human zygote? (Module 27.2B)

46

How many chromosomes do human somatic cells contain?

46

Why does a mother's blood volume increase during pregnancy? (Module 27.9B)

A mother's blood volume increases to accommodate for flow through the placenta.

Trisomy 21 is the clinical term for

Down syndrome.

Why does a man have a deeper voice and a larger larynx than a woman? (Module 27.13B)

During puberty, testosterone causes greater laryngeal development than estrogen so a male will have a larger larynx and a deeper voice.

________ is the time spent in growing within the uterus.

Gestation

All of the following occur at puberty except

GnRH levels decline.

Define lactation. (Module 26.14A)

Lactation is the production of milk by the mammary glands.

The reproductive system does not include

None of the answers is correct.

Define oocyte. (Module 26.10A)

Oocyte is an immature female gamete.

Define organogenesis. (Module 27.8A)

Organogenesis is the process of organ formation.

Define spermatogenesis. (Module 26.3A)

Spermatogenesis is the production of sperm using mitosis, meiosis, and spermiogenesis.

How can you tell that the karyotype shown here is male? (Module 27.14C)

The 23rd pair of chromosomes is XY.

Which event occurs during week 4 of development?

The connections between the embryo and the surrounding trophoblast begin to constrict.

Which is the resulting event if fertilization does not occur?

The corpus albicans is formed.

Describe the placenta. (Module 27.5C)

The placenta forms the interface between the embryonic/fetal system and the maternal system.

By the end of gestation, which of the following has not occurred?

The uterus has increased in size by 10 fold.

Fertilization is complete when which of the follow occurs?

amphimixis and cleavage

The spermatic cord is

a bundle of tissue that contains the ductus deferens, blood vessels, nerves, and lymphatics that serve the testis.

List the structures of a sperm. (Module 26.3C)

acrosome, head, neck, middle piece, and tail

When does the placenta become sufficiently functional to continue the pregnancy? (Module 27.7C)

after the first trimester

The various forms of any one gene are called

alleles

A space opens within the inner cell mass that will form the

amniotic cavity.

By day 12 of embryonic development, mesoderm begins to form through

gastrulation

Which of the following does not describe non-sex chromosomes?

haploid

At 8 months development in a male fetus, the testes

have been pulled through the abdominal musculature into the scrotum.

The ________ is the part of the sperm that contains the DNA.

head

Which of the following traits is a sex-linked inheritance?

hemophilia

If an individual carries a pair of alleles that are the same, the individual is ________ for the trait.

homozygous

The ________ method of birth control involves taking either combination estrogen/progesterone birth control pills or progesterone-only pills in two large doses 12 hours apart within 72 hours of unprotected sexual intercourse.

hormonal post-coital contraception

The funnel-like opening at the distal end of the uterine tube is called the

infundibulum.

The ________ is an opening through which the spermatic cord passes.

inguinal canal

The primary role of FSH in males is to

initiate sperm production in the testes.

Testosterone is secreted by the

interstitial cells

The production of milk is called

lactation

All of the following are true of the vagina except that it

loses a portion of its lining during menses.

In Klinefelter syndrome, __________.

the phenotype is male, but the extra X chromosome causes reduced androgen production

The endoderm forms

the urinary bladder.

A fetus undergoes its largest absolute weight gain during which trimester? (Module 27.8C)

third trimester

Deoxygenated blood is carried to the placenta by the

umbilical arteries.

Oxygenated blood is carried away from the placenta by the

umbilical vein.

The male reproductive system is most closely associated with which of the following systems?

urinary

How do autosomes and sex chromosomes differ? (Module 27.14B)

Autosomes are chromosome pairs 1-22 that affect somatic characteristics. Sex chromosomes are the 23rd pair that determine whether an individual is male (XY) or female (XX).

Describe the process of spermiation. (Module 26.4B)

During spermiation, a sperm loses its attachment to the nurse cell and enters the lumen of the seminiferous tubule.