Chapter 27 Homework

B) tail of the epididymis Sperm are stored in the tail of the epididymis until they are ejaculated. If they are not ejaculated, they will eventually break down and be phagocytized.

A) passage of sperm cells from the epididymis to the penis Since the ductus (vas) deferens is severed during a vasectomy, sperm cells can no longer pass from the epididymis to the penis.

D) production of sex hormones Primary sex organs have two main roles: production of the gametes and production of the sex hormones.

True Viable sperm cannot be produced in abundance at core body temperature (37 degrees Celsius). The superficial location of the scrotum, which holds the testes, provides a temperature about 3 degrees Celsius lower than core temperature so that viable sperm can be produced. Furthermore, the scrotum is affected by temperature changes. When it is cold, the scrotum reduces its surface area by becoming heavily wrinkled. It also shortens to pull the testes closer to the body wall. When it is warm, the scrotum becomes flaccid and loose to increase its surface area. The scrotum also hangs down from the body to keep the testes away from the warmer body trunk.

B) prepuce (foreskin) The prepuce, or foreskin, forms a covering of the glans penis and is removed during circumcision. This procedure may confer some health benefits, particularly in cases of chronic infection, and is also a common religious practice.

D) urethra The urethra is used to carry both sperm cells within semen and urine from the prostate to the tip of the penis.

A) epididymis: produce sperm The epididymis is where sperm is stored and matured.

B) urethra: clear, viscous mucus that neutralizes urine The bulbourethral gland produces a clear, viscous mucus that neutralizes urine.

C) spermatozoa The final product of spermiogenesis is spermatozoa. These will enter the lumen of the seminiferous tubule.

C) early spermatids Early spermatids have undergone both meiosis I and II, so these cells are haploid (23 chromosomes total) and all these chromosomes are unpaired.

A) 23; haploid

B) acrosome The acrosome contains the hydrolytic enzymes needed to digest the zona pellucida on the oocyte.

B) to prevent activation of the immune system of the male against the developing sperm A male's immune system would identify sperm as foreign bodies. The blood-testis barrier prevents that interaction.

D) sustentocytes (Sertoli cells) Sustentocytes in the walls of the seminiferous tubules respond to FSH by releasing androgen-binding protein, which maintains high testosterone levels near developing sperm cells.

B) testosterone Testosterone promotes the formation of secondary sex characteristics such as the appearance of pubic, axillary, and facial hair; enhanced hair growth on the chest; and a deepening voice.

B) interruption of sustentocytes' production of ABP Sustentocytes produce ABP to keep testosterone levels high near the spermatogenic cells. Low ABP would directly affect the amount of testosterone around the spermatogenic cells.

A) interstitial cells: androgen secretions In males, LH targets interstitial cells. As a result of LH stimulation of interstitial cells, the levels of androgens, such as testosterone, increase.

D) uterine (fallopian) tube Eggs that successfully implant in the uterus are fertilized in the uterine tube. This does not imply a "tubal pregnancy," where the zygote implants in the uterine tube.

B) myometrium As the prefix myo- implies, the myometrium is the thick, smooth muscle lining of the uterine wall. It has an enormous ability to stretch, and its contractions lead to delivery.

C) infundibulum, ampulla, isthmus, uterus After ovulation, the oocyte enters the infundibulum, travels through the ampulla and isthmus, and enters the uterus.

A) stratum functionalis; stratum basalis The stratum functionalis is shed as the spiral arteries retract into the stratum basalis. The stratum basalis then regenerates the functional layer back onto the basal layer.

B) decreased number of cilia in the uterine tubes The cilia within the fallopian tubes function to move an ovulated oocyte from the ovary to the uterus.

C) rectum

A) stratum functionalis of the endometrium Implantation occurs at the stratum functionalis.

A) areola

C) The number of functional gametes produced is different. In spermatogenesis, four functional gametes are produced, while oogenesis produces only one functional gamete because of the loss of three polar bodies.

B) ovulation Ovulation of the oocyte from the ovary occurs at around day 14 of the cycle, just as the uterine proliferative phase ends and the secretory phase begins.

A) menstrual phase The functional layer of the endometrium is shed during days 1 through 5 of the uterine cycle, a process called menses or menstruation.

D) the endometrium prepares for implantation Secretions in the endometrium during the secretory phase aide in implantation.

C) promotes oogenesis

C) the Y chromosome Males carry a Y chromosome, which is important in determining sex.

C) interstitial endocrine cells

C) relaxation of muscle tissue in arteries Smooth muscle relaxation would lead to vasodilatation of arteries. Remember that blood pressure is directly affected by blood vessel diameter.

B) four haploid cells.

B) interphase.

B) homologous chromosomes stick together in pairs.

C) prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.

D) prophase I.