Chapter 27 (Common and Male): The Reproductive System

What is the function of the reproductive system?

The production of offspring

What are the processes that allow the production of offspring?

1. Gamete formation

2. Copulation

3. Fertilization

4. Gestation and parturition

What happens during gamete formation?

Sperm and ova (egg) are formed?

What is copulation/

The process where sperm and egg must be brought together

What occurs during fertilization?

The combining of genetic content of the sperm and the egg

What happens during gestation and parturition?

Development and birth of the fetus (parturition means labor and delivery)

What are the male and female similarities of the reproductive system?

• meiosis. (I and II)

• Hypothalamic-Pituitary-Gonodal (HPG) axis

What is meiosis and where does it occur?

Nuclear division that occurs only in the gonads and results in the formation of gametes

What are the two important functions of meiosis?

1. Reduces the number of chromosomes in gametes by half, ensuring correct chromosome number after fertilization

2. Produces genetic variation by forming non-identical gametes

   • Promotes species survival

Before meiosis begins, what happens to chromosomes in a diploid parent cell?

Chromosomes replicate to form sister chromatids

What are sister chromatids?

Identical copies of a chromosome joined together after DNA replication

What is the first major event of meiosis I?

Homologous chromosome synapse to form tetrads, crossing over takes place

What is crossing over?

The exchange of genetic information between non-sister chromatids of homologous chromosomes increasing genetic variation

When does crossing over occur and what is its importance?

During prophase I ; it increases genetic variation in gametes

What happens after crossing over in Meiosis I?

Tetrads align randomly on the spindle plate (random assertion)

What then happens after tetrads align during meiosis I?

Homologous chromosomes separate and move to opposite poles; sister chromatids STAY TOGETHER!

What happens in meiosis I after homologous chromosomes seperate and move to opposite poles?

Cleavage occurs

What is the result of meiosis I?

Two haploid cells, each with duplicated chromosomes (sister chromatids still attached)

What are the key events of meiosis II?

1. Formation of a new spindle

2. Chromosomes line up at the equator

3. Sister chromatids separate and move to opposite poles

4. Cleavage occurs

What is the result of meiosis II?

4 haploid daughter cells with unreplicated chromosomes; no crossing over occurs

What is the hypothalalmic-pituitary gonadal axis?

The interaction of hormones from the hypothalamus, anterior pituitary, and gonads that regulate reproductive function

What are the main functions of the HPG axis?

1. Regulates reproductive hormone levels

2. Controls gametogenesis

3. Maintains sexual development, fertility, and reproductive function

What hormone does the hypothalamus release in the HPG axis?

Gonadotropin-releasing hormone (GnRH)

What hormones does the anterior pituitary release in response to gondotropin-releasing hormone?

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

What do the gonads do in response to LH and FSH?

Produce sex hormones and gametesW

What are important structures to the HPG axis?

1. Hypothalamus

2. Anterior pituitary glands

3. Gonads

What are the male gonads called and where are they located?

The testes, which are enclosed and protected by the scrotum

What is the scrotum made of?

Skin and superficial fascia

Why is the scrotum important?

Scrotum is important for sperm production. It allows the testes to remain about 3^o lower than internal body temperature, which is essential for sperm production

What happens to sperm production if testicular temperature increases?

Sperm production decrease

What does musculature do?

Allow testes to maintain optimal temperature

How does scrotal musculature help maintain optimal testicular temperature?

By adjusting the surface area and position of the testes

What is the function of dartos muscle?

It changes the surface area of the scrotal skin to control heat loss

• Contracts to wrinkle scrotal skin, reducing surface area

• Decreases heat to help maintain testicular temperature for sperm production

What is the function of the cremaster muscles?

It changes the position of the testes to regulate temperature

What does the cremaster muscle do when warm?

Relaxes to lower testes away from the body

What does the cremaster muscle do when cold?

Contracts to pull the testes closer to the body

Why is the temperature regulation by the cremaster and dartos muscles important?

It ensures optimal condition for sperm production

What vessels supply blood to the testes?

Testicular arteries

What vessels drain blood from the testes?

Testicular veins

How do testicular veins help regulate temperature?

They absorb heat from testicular arteries, cooling the blood before it reaches the testes-this aids sperm production

What divisions of the nervous system innervate the testes?

Both sympathetic and parasympathetic divisions

What structures make up the spermatic cord?

Nerve fibers, blood vessels, ductus deferens, and lymphatics

What is the function of the seminferous tubules?

They are the site of sperm production

What is the path of immature sperm from the seminiferous tubules?

Seminiferous tubules→rete testis→epididymis

What is the role of the rete testis?

It allows the sperm to leave the testis and enter the epididymis for further maturation

What hormone can testicular cancer cells produce, and why is this unusual?

hCG, which is usually produce by pregnant women

What is testicular cancer?

The formation of malignant tumor in one or both testes

What are the two main types of testicular cancer?

Seminoma and non-seminoma

What are the characteristics of seminoma?

• Slow growing

• Not agressive

• slighty more common

What are the characteristics of non-seminoma?

• More aggressive

• Cancer cells spread more quickly

• Worse prognosis

What are the common symptoms of testicular cancer?

• Painless lump or swelling of the testis

• Dull pain in the lower pelvis and/or lower back

What are risk factors or causes of testicular cancer?

• Genetics and family history

• Klinefleter syndrome (XXY chromosome pattern)

• Persistent or chronic inflammation

What are the treatment options for testicular cancer?

Chemotherapy, radiation, and surgery

What are accessory ducts to testes?

1. Epididymis

2. Ductus Deferens

3. Urethra

What is the function of the epididymis?

It stores immature sperm and is where sperm gain the ability to swim as they travel through

What happens to sperm that do not leave the epididymis?

They are phagocytized if not used or if genetically defective

What is the function of the ductus deferens?

It transports sperm from the epididymis during ejaculation

Where does the ductus deferens end?

At the ampulla, which then joins the ejaculatory duct

What does the ejaculatory duct do?

It empties sperm into the urethra

What is a vasectomy?

A procedure where the ductus deferens is cut or cauterized to prevent sperm transport; can be reversible but takes 2-3 months to become effective

What is the urethra’s role in the male reproductive system?

It is the terminal portion of the duct system that carries sperm and urine to the outside of the body

What are the three division of the male urethra?

1. Prostatic urethra

2. Intermediate part

3. Spongy urethra

What is the prostatic urethra?

Portion surrounded by prostate gland

What is the intermediate part of the male urethra?

Connects prostatic urethra to spongy urethra

• Travels back through body wall

What is the spongy urethra?

Runs through the penis and opens to the exterior of the body

What is the function of the penis?

To deliver sperm to female reproductive tract during copulation

What does the penis end in?

Glans

What ist he glans surrounded in?

Prepuce

What is prepuce

Foreskin (technically not necessary)

What is the internal anatomy of the penis?

Erectile tissues

What is erectile tissues?

Contains connective tissue, smooth muscle, and vascular space

The vascular space of the penis fills with..

Blood

How many erectile bodies are there?

1. Corpus spongiosum

2. Corpora cavernosa

What is the corpus spongiosum?

Immediately surrounds urethra

• Distal portion forms glands

What does the corpus spongiosum do?

Keeps urethra open

What is the corpora cavernosa?

Paired structures (left and right)that make up most of the penile tissues

What makes up the bulk of erectile tissues in penis?

Corpora cavernosa

What are the main accessory glands of the male reproductive systems?

1. Seminal glands

2. Prostate gland

3. Bulbo-urethral glands

Where do the seminal gland empty their secretions?

Into the ejaculatory duct

What do the seminal glands secrete?

Fructose, prostaglandins, and proteins

What is the function of the fructose in seminal fluid?

It provides energy for spermW

What is the function of prostaglandins in semen?

They help stimulate a smooth muscle contractions in the female reproductive tract

How many glands compose the prostate gland?

20-30 glands

What substance does the prostate gland produce?

Citrate, prostate-specific antigen (PSA), and other substances that help activate sperm

What is the role PSA?

It breaks down and liquifies semen to help it flow more easily during ejaculation

What happens to the smooth muscle walls of the prostate during ejaculation?

They contract to release glandular contents into the urethra

How common is prostate cancer?

1 in 6 men will develop it, usually later in life (50+)

How does prostate cancer vary in severity?

It can range from slow-growing to highly aggressive

Do most men die from prostate cancer?

No, most men die with it, not because of it

What are the symptoms of prostate center?

• Difficulty urinating

• Blood in urine and/or semen

• Erectile disfunction

• Often symptomless in early stages

Why can prostate cancer cause difficult urinating?

An enlarged prostate can compress (pinch) the prostatic urethra, slowing or blocking urine flow

What are the homeostatic imbalances of the prostate?

Prostate cancer, Benign prostatic hyperplasia

What is benign prostatic hyperplasia?

A non-cancerous enlargement of the prostate caused by rapidly dividing but normal cells

What effect does Benign Prostatic Hyperplasia habe on the urethra?

It constrict the prostatic urethra, making urination difficult and painful

What do bulbo-urethral glands produce?

Alkaline mucus (mixes with other seminal fluids and sperm)

What is the purpose of the alkaline mucus produces by the bulbo-urethral glands?

To neutralize acidic urine left in the urethra

Why is it important to neutralize acidic urine in the urethra?

Because sperm do not survive well in acidic conditions, and this creates a more favorable environment for them

What is semen?

A mixture of sperm and accessory gland secretions

What are the components of the seminal secretions?

1. Prostaglandins

2. Relacin

3. Fructose

4. Antibiotic components

5. Clotting factos

6. Other

What is the function of prostaglandins in semen?

1. Decrease viscosity of mucus ini the female cervix

2. Stimulate reverse persistalsis in the uterus

3. Mainly affect the female reproductive system