Chapter 27: MALE

Primary Sex Organs

testes and ovaries AKA gonads

What do testes and ovaries produce?

gametes (sperm and ova)

Gametes secrete what sex hormone?

steroid

Sperm secretes what steroid sex hormone?

androgens

Ova secretes what steroid sex hormone?

estrogens and progesterone

Accessory Reproductive Organs

ducts, glands, and external genitalia

Body cells have what number of chromosomes?

46

There are two sets of chromosomes which contains how many?

23

Maternal and Paternal are referred to as:

homologous chromosomes

46 chromosomes are referred to as:

diploud chromosomal number (2n)

23 chromosomes are reffered to as:

haploid chromosomal number (n)

Haploid chromosomal number only contains ___ member of homologous pair.

one

Gamete formation involves what process?

meiosis

Meosis involves:

2 consecutive cell dividions and one round of DNA replication

Meosis produces:

4 daughter cells

Functions of Meosis

number of chromosomes are cut in half (2n -> n), introduces genetic diversity (daughter cells are genetically different from original cell)

During Meosis 1, the number of reduces from ____ to ____.

2n to n

What phase is not seen in mitosis or meiosis II?

prophase I

Synapsis

homologous chromosomes pair up fromaing tetrads consisting of 4 chromatids

Crossover (Chiasmata)

exchange of genetic material between male and female chromatids

The Crossover (Chiasmata) results in:

unique chromosomes that are mixtures of materal and paternal chromosomes

What happens during metaphase I?

tetrads line up randomly at spindle equator

What happens during anaphase I?

sister chromatids of one homologous chromosome are separated from sister chromatids of other

At the end of meiosis I, each daughter cell has how many copies?

2 copies of one member of each homologous pair and none of the other

At the end of meiosis I, each daugter cell has haploid chromosomal number because:

still-united sister chromatids are considered one chromosome

At the end of meiosis I, haploid chromosomal cells are considered one, why?

they contain twice the amount of DNA in each chromosome

First Task Meiosis I Accomplishes:

reduces chromosomal number by half

Second Task Meiosis I Accomplishes:

Introduces genetic variability

What leads to genetic variability?

random alignment of homologous paurs in meiosis I

Crossover is also known as:

variability of gametes

Crossover results in 2 gametes that are exactly alike OR exactly different?

exactly different (no two gametes are alike, they are all different from original mother cells)

Meiosis II results in:

equational division

What is the difference between meiosis and mitosis?

in meiosis, there are no chromosome replication before the process begins

In meiosis I, sister chromatids are separated OR aligned in meiosis II?

separate, they are pulled to opposite sides of poles

Meiosis II results in how many chromatids per cell?

one

Spermatogenesis

production of sperm in the seminiferous tubules

Spermatogenic cells give rise to:

sperm

3 Steps of Spermatogenesis

mitosis, meiosis, spermiogenesis

Mitosis of Spermatogonia

forms 2 spermatocytes

Meiosis

spermatocutes form secondary spermatocytes, which form spermatids

Spermiogenesis

spermatids become sperm

How long does spermatogenesis take?

64-72 days if conditions are hospitable

What pressure pushes immotile sperm to gain motility and fertilizing power?

testicular fluid into epididymis

When does spermatogenesis begin?

puberty

Spermatogenesis begins with:

spermatogonia

During spermatogonia, stem cells are in contact with:

epithelial basal lamina

During spermatogonia, mitotic division yields two types of one:

type A daughter cell and type B daughter cell

Function of Type A Cells

maintain germ cell line at basal lamina

Function of Type B Cells

move toward lumen and develop into primary spermatocytes

In meiosis, spermatocyte become:

spermatids

Primary spermatocytes will undergo meiosis I, forming:

two secondary spermatocytes

Secondary spermatocytes rapidly undergo meiosis II, becoming:

two spermatids

Spermatids

small, nonmotile cells found close to lumen of tubule

Spermigenesis convert spermatids to:

sperm

Spermatids contain the correct number of what for fertilization?

haploid chromosome

Spermiogenesis is a streamlining process where:

spermatid elongates, loses excess cytoplasm, and forms tail to become a spermatozoon (sperm)

Sperm Production: Head

genetic region that includes nucleus and helmetlike acrosome containing hydrolytic enzymes that enable sperm to penetrate egg

Sperm Production: Midpiece

metabolic region containg mitochondria that produce ATP to move tail

Sperm Production: Tail

locomotor region that include flagellum

Testes

sperm-producing male gonads that lie within the scrotum

The delivery of sperm in ORDER

epididymis, ductus deferens, ejaculatory duct, urethra

Accessory Sex Glands for Males

seminal glands, prostate, and bulbo-urethral glands

Scrotum

sac of skin and superficial fascia

Location of Scrotum

hangs outside abdiminopelvic cavity

Composition of Scrotum

paired testes

Temperature of Scrotum

3°C lower than core body temperature, low temp = necessary for sperm production

Testes are surround by two tunics which are called:

Tunica vaginalis and tunica albuginea

Tunica Vaginalis

outer layer derived peritoneum

Tunica Albuginea

inner layer forms fibrous capsule

What divided the testis into ~250 lobules that can contain 1-4 seminiferoys tubules?

septa

What is the site of sperm production?

testes

Where do testicular arteries arise from?

abdominal aorta

Where do testicular veins arise from?

pampiniform venous plexus which surround each testicular artery

Testicular veins absorb heat from where and why?

testicular arteries because they are cooler

Spermatic Cord

encloses nerve fibers, blood vessels, and lumphatics that supply testes

Order of Sperm Conveying

seminiferous tubules, straight tubule, rate testis, efferent ductules, epididymis

What makes up the epididymis?

head, body, and tail

Where is sperm stored and prepared for ejaculation?

tail

Interstitial Endocrine Cells

located in soft tissue surrounding seminiferous tubules

Production of Interstitial Endocrine Cells

androgens, such as testosterone

Secretion of Interstitial Endocrine Cells

interstitial fluid

Penis

male copulatory organ

External Genitalia

scrotum and penis

What does the penis consist of?

root, shaft, glans penis, prepuce

Prepuce (Foreskin)

cuff of loose skin covering glans

Composition of Penis

spongy urethra, 3 cylindrical bodies of erectile tissue, spongy network of connective tissue, and smooth muscle with vascular spaces

Corpus Spongiosum

surronds urethra and expands to form glans and bulb

Corpora Cavernosa

paired dorsal erectile bodies

Erection

erectile tissue fills with blood, causing penis to enlarge and become rigid

Ducts carry sperm from testes to body exterior through:

epididmyis, ductus deferens, ejaculatory duct, and urethra

Epididymis

nonmotile sperm enter, pass slowly through (~20 days), become motile

Sperm can be stored in the epididmyis for how long?

several months

During ejaculation, epididymis contracts which causes:

expelling of sperm into ductus deferens

How long is the ductus deferens?

~ 45 cm long

The ductus deferens passes through the ________ cavity to _______ cavity

inguinal, pelvic

The ductus deferens joins what vesicle to form the ejaculatory duct?

seminal

What muscle propels sperm from epididymis to urethra?

smooth

Vasectomy

cutting and ligating ductus deferens

A vasectomy is nearly 100% effective form of:

birth control

Urethra

conveys both urine and semen (at different times)