Human Male Reproductive System Quiz

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Questions and Answers

What is the primary function of the Sertoli cells during spermatogenesis?

To produce testosterone and regulate libido

To facilitate the transformation of spermatids into spermatozoa (correct)

To control the release of GnRH from the hypothalamus

To protect developing sperm from the immune system (correct)

Which phase must occur before ejaculation can take place in the male sexual response?

Erection and pelvic contraction (correct)

Testosterone release from the testes

Production of FSH from the anterior pituitary

Meiosis of spermatocytes

Which of the following is NOT a common cause of erectile dysfunction?

Performance anxiety

Testosterone deficiency

Diabetes

High levels of dopamine (correct)

At what age does spermatogenesis typically begin in males?

Age 14 Signup and view all the answers

Which hormone is primarily responsible for regulating spermatogenesis in males?

Follicle-stimulating hormone (FSH) Signup and view all the answers

What initiates the process of increased blood flow during an erection?

Nerve stimulation and release of nitric oxide Signup and view all the answers

What is the consequence of tight junctions between Sertoli cells during spermatogenesis?

Protection against immune system attacks Signup and view all the answers

Which event occurs after a primary spermatocyte undergoes meiosis?

Formation of spermatids Signup and view all the answers

What is the primary function of FSH in the process of spermatogenesis?

Initiating and supporting the early stages of spermatogenesis Signup and view all the answers

Which hormone is released by Sertoli cells to inhibit FSH secretion?

Inhibin Signup and view all the answers

How does testosterone affect the maturation of spermatozoa?

It is essential for maturation through the epididymis Signup and view all the answers

What are secondary sexual characteristics developed under the influence of testosterone?

Hair growth and changes in skin texture Signup and view all the answers

What physiological effect does inhibin have on sperm production when its levels decrease?

Increases FSH secretion Signup and view all the answers

Which of the following best describes the role of ABP in spermatogenesis?

It mediates testosterone's action in Sertoli cells Signup and view all the answers

What hormonal change triggers the release of more FSH when sperm maturation is insufficient?

Lower levels of inhibin Signup and view all the answers

Testosterone and dihydrotestosterone produced by Leydig cells are critical for which function?

Sexual differentiation and maintenance of spermatogenesis Signup and view all the answers

What is the primary neurotransmitter responsible for the relaxation of smooth muscle during the erection process?

Nitric Oxide Signup and view all the answers

During ejaculation, what function does the sympathetic nervous system primarily control?

Constriction of bladder sphincters Signup and view all the answers

What is a common consequence of varicocele that may affect male fertility?

Higher oxidative stress and testicular temperature Signup and view all the answers

Which of the following correctly describes the process of erection?

It is mediated by the parasympathetic nervous system and vasodilation. Signup and view all the answers

What initiates the sexual response leading to an erection?

Stimuli such as touch, sound, or smell activating the CNS Signup and view all the answers

Which physiological response occurs immediately following ejaculation?

Relaxation and a refractory period Signup and view all the answers

What congenital defect is characterized by an abnormal opening of the urethra on the penis?

Hypospadias Signup and view all the answers

What element is primarily responsible for increasing oxidative stress and potentially affecting semen quality in cases of varicocele?

Increased testicular temperature Signup and view all the answers

Study Notes

Inguinal Hernias

The processus vaginalis is a potential weak spot and is the route taken by indirect inguinal hernias.

Varicocele

Varicocele is the enlargement of the testicular venous pampiniform plexus.
It can increase testicular temperature and oxidative stress.
May impact semen quality.
Surgical treatment may restore fertility.

Penis

The penis is made up of:
- Two corpora cavernosa
- One corpus spongiosum
- Glans
- Corona
- Root
- Bulb
Hypospadias is a congenital defect.

Erection

Sexual stimuli can be touch, sound, smell, emotional, or mental activity.
The CNS activates the parasympathetic nervous system, resulting in an enlargement and stiffening of the penis.
The penis is flaccid with a constricted blood supply when a male is not sexually aroused.
Erection is mediated through the parasympathetic nervous system and release of Nitric Oxide (NO).
NO relaxes smooth muscle cells (SMC), dilating blood vessels and allowing blood to fill the erectile bodies.
Corpus cavernosa and spongiosum fill with blood, restricting veins.

Ejaculation

Ejaculation is mediated by the sympathetic nervous system via a mass spinal reflex causing:
- Constriction of the bladder sphincter muscle - preventing expulsion of urine or reflux of semen into the bladder
- Contraction of the ducts and glands – emptying substances into the urethra
- Contraction of the penis muscles to ‘shoot forth’ semen – speed up to 500 cm/s

Male Sexual Response

The male sexual response has main phases including:
- Erection
- Ejaculation
An event or climax or orgasm → Resolution period (relaxation) – Unable to achieve another orgasms for minutes during the latent or refractory period.

Erectile Dysfunction

Erectile dysfunction is the failure to achieve or maintain an erection.
Highly common, ~50% of men between 40-70 years old.
May be physical or psychological.
Testosterone deficiency, Diabetes & Cardiovascular disease, Stress, performance anxiety, and drugs, e.g. SSRIs, antihypertensives, recreational drugs, are all examples.
Sildenafil was initially a drug for angina.
Relaxation of coronary arteries → increased blood flow → pain relief.

Spermatogenesis

A sequence of events that produces sperm (male gametes) in the seminiferous tubules of the testes.
Begins at around the age of 14 and continues throughout life.
Healthy adult male produces ~400 million sperm/day.
Gamete formation involves meiosis.
A unique type of nuclear formation that occurs in the gonads.
The rate of spermatogenesis is determined by the hormones testosterone and FSH.

Spermatogenic cells

Spermatogenic cells include:
- Spermatogonia stem cells - divide by mitosis.
- Type A cells - remain in the basal lamina.
- Type B cells - become the primary spermatocyte.
- Primary spermatocyte - undergoes meiosis to make secondary spermatocytes.
- Secondary spermatocytes - produce spermatids by meiosis II.
- Spermatids – produce sperm cells/spermatazoa.
- Sertoli cells - produce Inhibin andAndrogen Binding Protein

Spermatogenesis Cytoplasmic Bridges

Cytoplasmic bridges ensure sperm develop at the same rate.
Tight Junctions stop the immune system attacking genetically different sperm.

Hormones

Steroid hormone release is regulated by negative feedback.
Inhibin inhibits FSH release.
Sertoli cells secrete inhibin, a peptide hormone essential for sperm maturation.

Endocrine Regulation of Testis function

The testes are responsible for spermatogenesis and steroidogenesis.
FSH is essential for the initiation and first stages of spermatogenesis.
Testosterone is important for sperm maturation in the epididymis through Sertoli cell secretion of Androgen Binding Protein (ABP).
Androgens:
- Testosterone and Dihydrotestosterone are produced by Leydig cells.
- Ligands of the Androgen nuclear hormone receptor (AR).
- Responsible for:
  - Sexual differentiation and development (in utero)
  - Sexual maturation (puberty)
  - Maintenance of spermatogenesis (adulthood)

Effects of Testosterone

Responsible for development of male primary and secondary sexual characteristics:
- Primary sexual characteristics:
  - Enlargement / differentiation of the male genitalia
  - Ability to produce sperm cells
- Secondary sexual characteristics:
  - Hair growth and distribution
  - Skin texture
  - Changes in the larynx
  - Increased metabolism
  - Skeletal muscle and bone development

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Description

Test your knowledge on the human male reproductive system, covering topics such as inguinal hernias, varicocele, anatomical structures of the penis, and the physiology of erection. Understand the implications of various conditions and their impact on male health and fertility.