Exam 7 Ch 27

Why are the testes located outside of the body cavity?

Because spermatogenesis requires a temperature slightly lower than body temperature.

What muscle regulates testicular temperature by wrinkling the scrotal skin?

Dartos muscle.

What is the function of the dartos muscle?

It wrinkles the scrotal skin to reduce heat loss and helps regulate testicular temperature.

What is the function of the cremaster muscle?

Raises or lowers the testes to regulate temperature.

What are seminiferous tubules?

Structures in the testes where sperm production (spermatogenesis) occurs.

What are spermatogenic cells?

Cells that divide and develop into sperm.

What are Sertoli cells (sustenocytes)?

 Cells that support developing sperm, nourish sperm cells, and regulate spermatogenesis.

What do Sertoli cells produce that helps sperm development?

Androgen-binding protein (ABP) and inhibin.

What is the function of myoid cells?

They contract to help move sperm through seminiferous tubules.

What are interstitial endocrine cells (Leydig cells)?

Cells that produce testosterone.

What is erectile tissue?

Tissue containing blood-filled spaces that become engorged during erection.

What are the two types of erectile tissue in the penis?

Corpora cavernosa and corpus spongiosum.

Which erectile tissue surrounds the urethra?

Corpus spongiosum.

What is the function of the epididymis?

Stores sperm and allows sperm to mature and gain motility.

What happens to sperm in the epididymis?

They mature and become capable of movement.

What is the function of the ductus deferens?

Transports sperm from the epididymis toward the ejaculatory duct.

What is a vasectomy?

A procedure where the ductus deferens is cut or blocked to prevent sperm from entering semen.

What are the three male accessory glands?

Seminal glands, prostate gland, and bulbourethral glands.

What is the function of the seminal glands?

Produce fluid containing fructose and prostaglandins that nourish and support sperm.

What is the role of fructose in semen?

Provides energy for sperm movement.

What is the role of prostaglandins in semen?

Stimulate contractions in the female reproductive tract to help sperm movement.

What is the function of the prostate gland?

Produces a milky fluid that helps activate sperm and contributes to semen.

What is the function of the bulbourethral glands?

Produce mucus that lubricates and neutralizes acidic urine in the urethra.

Which division of the autonomic nervous system controls erection?

Parasympathetic nervous system.

What neurotransmitter causes erection by increasing blood flow?

Nitric oxide (NO).

What happens during erection?

Erectile tissue fills with blood, causing expansion and restricting venous return.

Which division of the autonomic nervous system controls ejaculation?

Sympathetic nervous system.

What is the chromosome number in humans?

46 chromosomes (2n).

What does haploid (n) mean?

One set of chromosomes; humans have 23 chromosomes.

What does diploid (2n) mean?

Two sets of chromosomes; humans have 46 chromosomes.

How many pairs of homologous chromosomes do humans have?

23 pairs.

Where do homologous chromosomes come from?

One chromosome from each parent.

What is the main purpose of meiosis?

To produce haploid gametes and create genetic variation.

Why is meiosis called a reduction division?

It reduces chromosome number from diploid (2n) to haploid (n).

What are two sources of genetic variation during meiosis?

Crossing over and independent assortment.

When does crossing over occur?

Prophase I of meiosis.

When does independent assortment occur?

Metaphase I of meiosis.

 What happens during meiosis I?

Homologous chromosomes separate, reducing chromosome number from 2n to n.

What happens during meiosis II?

Sister chromatids separate (similar to mitosis).

What is the final result of meiosis?

Four haploid gametes.

What is spermatogenesis?

The process of sperm production.

Where does spermatogenesis occur?

Seminiferous tubules.

What is the first cell in spermatogenesis?

Spermatogonium (2n).

Spermatogonia develop into what cell?

Primary spermatocyte.

What does meiosis I produce during spermatogenesis?

Two secondary spermatocytes.

What does meiosis II produce during spermatogenesis?

Four spermatids.

What is spermiogenesis?

The process where spermatids develop into mature spermatozoa.

What happens during spermiogenesis?

Spermatids develop a head, midpiece, and tail.

What are the three regions of sperm?

Head, midpiece, and tail.

What is found in the head of sperm?

Nucleus and acrosome.

What is the function of the acrosome?

Contains enzymes needed to penetrate the oocyte.

What is the function of the midpiece?

Contains mitochondria that provide energy.

What is the function of the tail?

Provides movement.

What hormone stimulates sperm production by acting on Sertoli cells?

Follicle-stimulating hormone (FSH).

What hormone stimulates testosterone production in the testes?

Luteinizing hormone (LH).

Which cells produce testosterone?

Interstitial endocrine cells (Leydig cells).

What is androgen-binding protein (ABP)?

A protein produced by Sertoli cells that keeps testosterone concentrated in the seminiferous tubules for sperm production.

What effect does inhibin have on FSH release?

It decreases FSH secretion through negative feedback.

What hormone is testosterone synthesized from?

Cholesterol.

What hormone can testosterone be converted into?

Dihydrotestosterone (DHT).

What are the functions of testosterone?

Promotes spermatogenesis. Stimulates accessory gland activity. Causes male secondary sex characteristics. Supports male sexual behavior.

What happens with testosterone deficiency?

Reduced sperm production, decreased male secondary sex characteristics, and decreased reproductive function.

What are male secondary sex characteristics caused by testosterone?

Increased muscle growth. Deeper voice. Facial/body hair growth. Male body development

What are the main functions of the ovaries?

 Produce eggs (gametes) and secrete estrogen and progesterone.

What is an ovarian follicle?

A structure that surrounds and supports a developing egg.

What is the most mature ovarian follicle stage?

 Antral follicle.

What are follicular cells?

Cells that surround and support the developing oocyte.

What do granulosa cells produce?

Estrogen.

What happens to the follicle after ovulation?

It becomes the corpus luteum.

What hormone does the corpus luteum produce?

Progesterone.

What is the function of progesterone from the corpus luteum?

Maintains and prepares the endometrium for implantation.

What happens to the corpus luteum if implantation does not occur?

 It degenerates into a corpus albicans.

What are fimbriae?

Finger-like projections that help capture the ovulated oocyte.

Where does fertilization normally occur?

Ampulla of the uterine tube.

What processes move the egg toward the uterus?

Cilia movement and smooth muscle contractions (peristalsis).

 What is an ectopic pregnancy?

 Implantation of an embryo outside the uterus, commonly in the uterine tube.

What can cause an ectopic pregnancy?

 Reverse peristalsis or blocked/damaged uterine tubes.

What is the primary function of the uterus?

Provides a place for implantation and fetal development.

What are the three layers of the uterus?

Perimetrium, myometrium, and endometrium.

What is the function of the myometrium?

Smooth muscle layer that contracts during childbirth.

What are the two layers of the endometrium?

Functional layer and basal layer

Which layer of the endometrium is shed during menstruation?

Functional layer (stratum functionalis).

How is the functional layer replaced after menstruation?

The basal layer regenerates it.

How do estrogen and progesterone affect cervical mucus?

Estrogen thins cervical mucus to allow sperm entry; progesterone thickens it.

What are risk factors for cervical cancer?

HPV infection, STIs, and frequent cervical inflammation.

What are the three functions of the vagina?

Birth canal. Receives semen during intercourse. Passageway for menstrual flow.

 What type of epithelium lines the vagina?

Stratified squamous epithelium.

What is the normal pH of the adult vagina?

Acidic.

What female structure is homologous to the male scrotum?

 Labia majora.

What female structure is homologous to the male bulbourethral glands?

Greater vestibular glands.

What female structure is homologous to the glans penis?

Clitoris.

What is oogenesis?

The process of producing female gametes (eggs).

When does oogenesis begin?

 Before birth.

What cell does oogenesis begin with?

Oogonium (2n).

What does a primary oocyte produce after meiosis I?

Secondary oocyte + first polar body.

When does the secondary oocyte complete meiosis II?

Only if fertilization occurs.

What are the products of meiosis II in oogenesis?

Ovum + second polar body.

Why does oogenesis produce only one egg?

Unequal division preserves cytoplasm and nutrients for the developing embryo.

When does spermatogenesis begin?

At puberty.

When does oogenesis begin?

Before birth.