Why do we have reproductive systems? BI 203 Human Anatomy & Physiology II Why do we have reproductive systems? We get one life to live… Hebrews 9:27 And as it is appointed unto men once to die, but after this the judgment: We can’t reproduce asexually (outside of the lab) In order to pass on a part of ourselves to a new generation…

BI 203 Human Anatomy & Physiology II

How do we “pass on part of ourselves”? BI 203 Human Anatomy & Physiology II How do we “pass on part of ourselves”? 1) Form a sex cell (gametes) that can unite with a cell of the opposite sex (egg or sperm) 2) Introduce those gametes -------------------------------------------------------------- 3) Provide a mechanism for development 4) Provide a means for the baby to become autonomous (birth) 5) Continued care after birth

Where in the body is it found? What are chromosomes? BI 203 Human Anatomy & Physiology II What is DNA? Where in the body is it found? What are chromosomes? How many chromosomes in the human cell? How are new people formed? Do eggs and sperm have nuclei? How many chromosomes in a zygote (fertilized egg)? How? Genetic code for life (“blueprint”) Every cell with a nucleus Coiled up DNA and proteins 46 (diploid cells) Union of gametes (egg and sperm) Yes 46 (diploid cell) The “magic” of meiosis

BI 203 Human Anatomy & Physiology II How does meiosis result in cells with “half” of a full set of chromosomes (haploid)? http://www.youtube.com/watch?v=uh7c8YbYGqo&NR=1

BI 203 Human Anatomy & Physiology II How does meiosis result in cells with “half” of a full set of chromosomes (haploid)?

How does meiosis relate to spermatocytes? BI 203 Human Anatomy & Physiology II How does meiosis relate to spermatocytes?

How does meiosis relate to oocytes? BI 203 Human Anatomy & Physiology II How does meiosis relate to oocytes?

What are the reproductive components required of males? BI 203 Human Anatomy & Physiology II What are the reproductive components required of males? 1) Gonads (create gametes) 2) Glands (contribute to semen) 3) Ducts (transport the products) 4) Penis (copulation and transfer)

What is the route of a sperm cell? BI 203 Human Anatomy & Physiology II What is the route of a sperm cell? Testes (2, contained in the scrotum) Epididymis (convoluted tube for sperm maturation) Vas deferens (ascends through spermatic cord) Seminal vesicles (glands producing seminal fluids) Ejaculatory ducts (conduct seminal vesicle fluids to urethra) Prostate gland (gland contributing to semen) Bulbourethral gland (gland contributing to semen) Urethra - penis (transport for semen and copulatory organ)

What is the route of a sperm cell? BI 203 Human Anatomy & Physiology II What is the route of a sperm cell?

What are some of the male external anatomical features? BI 203 Human Anatomy & Physiology II What are some of the male external anatomical features? Perineum Penis (shaft, glans, prepuce, meatus) Scrotum (Raphe=septum, and dartos muscle)

BI 203 Human Anatomy & Physiology II Testes originate in the abdominal cavity, so how do they get into the scrotum?

What are the important features of testes? BI 203 Human Anatomy & Physiology II What are the important features of testes? Small organs with exocrine and endocrine function Which products are which? Covered with tunica albuginea Connective tissue enters testes forming septa Septa form lobules Seminiferous tubules and stroma within lobules. Interstitual cells (Leydig cells) in the stroma = testosterone

What are the important features of testes? BI 203 Human Anatomy & Physiology II What are the important features of testes? Seminiferous tubules contain 2 primary cell types 1) Germ cells that go through spermatogenesis (see 28.4) 2) Sertoli (otherwise known as sustenacular or nurse cells) Sperm cells (spermatozoa) are released and move to epididymis)

Why an epididymis rather than a simple duct? BI 203 Human Anatomy & Physiology II Why an epididymis rather than a simple duct? Seminiferous tubules empty into epididymis Sperm cells mature here and await release via ejaculation Epididymitis inflammation of the epididymis due to infections Spermatocoele epididymis engorged with sperm cells (may follow a vasectomy

What comprises the spermatic cord? BI 203 Human Anatomy & Physiology II What comprises the spermatic cord? Spermatic cord is comprised of connective and muscle (cremaster) tissue and contains a number of structures: 1) Vas deferens (conducts sperm) 2) Testicular artery 3) Testicular vein (venous plexus) 4) Lymph vessels 5) Genital (testicular) nerve Ascends through inguinal canal

What explains the BB effect? BI 203 Human Anatomy & Physiology II What explains the BB effect? Simon Birch http://www.youtube.com/watch?v=H2fKeXrJXPo

What is the role of the seminal vesicles? BI 203 Human Anatomy & Physiology II What is the role of the seminal vesicles? Small glands that empty secretions into the ejaculatory duct to join sperm forming semen constitutes ~ 60% of semen fluid Contains mucus, fructose, fibrinogen and prostaglandins What is the role of each of the 4 components?

What is the role of the prostate gland? BI 203 Human Anatomy & Physiology II What is the role of the prostate gland? Prostate gland surrounds the urethra (prostatic urethra) and ejaculatory ducts Contributes ~ 30% to semen volume Prostatic fluids have high pH these neutralize acidic urethra, also clotting factors and fibrinolysin Why? Checking for Prostate CA

When/where does semen enter the urethra? BI 203 Human Anatomy & Physiology II When/where does semen enter the urethra? 3 regions: 1) prostatic 2) membranous 3) spongy Bulbourethral glands also contribute to semen ~ 5% Other 5% ? 75-400 million sperm/ml of semen @ 2-5ml

What events are involved with joining gametes? BI 203 Human Anatomy & Physiology II What events are involved with joining gametes? Sexual arousal via psychic and/or physical stimuli (tempered by testosterone) integrated in sacral region of spinal cord. 1) Erection Penal arteries dilate causing cavities in corpuses (what are they ?) to fill with blood. Venous return is restricted and engorgement results

What events are involved with joining gametes? BI 203 Human Anatomy & Physiology II What events are involved with joining gametes? Sexual arousal via psychic and/or physical stimuli (tempered by testosterone) integrated in sacral region of spinal cord. 1) Erection Penal arteries dilate causing cavities in corpuses (what are they ?) to fill with blood. Venous return is restricted and engorgement results Erectile tissue surrounded by inelastic connective tissue covering Penis becomes rigid

What events are involved with joining gametes? BI 203 Human Anatomy & Physiology II What events are involved with joining gametes? 2) Emission Semen accumulates in urethra. Seminal vesicles, prostate gland are stimulated to release secretions into prostatic urethra Engorgement and urethral irritation contribute to arousal Sperm moved from epididymides via peristaltsis of vas deferens The bulbourethral gland and urethral mucous glands secrete mucus 3) Ejaculation Rhythmic contractions expel semen

Glands/regions involved: 1) Hypothalamus 2) Pituitary 3) Testes BI 203 Human Anatomy & Physiology II Glands/regions involved: 1) Hypothalamus 2) Pituitary 3) Testes Hormones involved: 1) GnRH 2) LH, FSH 3) Testosterone, Inhibin