lecture 13

lecture 13 - Human Reproduction Why learn about...

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1 Human Reproduction Why learn about Reproduction?
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2 How does Reproduction Work? External Fertilization • Frogs meet at the edge of ponds, where the male mounts the female and stimulates her to release her eggs which stimulates her to release her eggs, which the male fertilizes with a cloud of sperm. Fig. 25-6
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3 Internal Fertilization Allows reproduction on land. Fig. 25-7 Birds do it, bees do it…but how do humans do it??
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4
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5 • Sperm are produced in the testes. Testes filled with epididymis vas deferens • Testes filled with seminiferous tubules, in which sperm produced uncoiled seminiferous tubule testis daughter cells A section through the testis spermatogonia (a) • Sertoli cells between tubules produce testosterone Fig. 25-9 sperm Sertoli cells Cross section of a seminiferous tubule (b) A Human Sperm Cell tail sheath nucleus acrosome Very little cytoplasm flagellum Tail Body Head mitochondria Acrosome dissolves the protective layers around the egg Body full of mitochondria to power tail Tail propels sperm through the female reproductive tract Fig. 25-11
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6 Urethra—conducts both urine and semen out of the body pubic bone urinary bladder ureter – Semen: 5% sperm rectum seminal vesicle prostate gland penis urethra mixed with secretions from 3 glands that empty into the vas deferens or urethra: The seminal vesicles bulbourethral gland scrotum urethral opening vas deferens epididymis testis The prostate gland The bulbourethral glands THE PATH OF SPERM During ejaculation, sperm move from the male body as follows: Vas deferens MATURATION Sperm mature in the epididymis. STORAGE AND 1 2 2 Urethra—conducts both urine and semen out of the body Seminal vesicle Ejaculatory duct Prostate Bulbourethral gland Bladder Penis TRANSFER Muscle contractions cause sperm to move from epididymis through vas deferens. 3 At ejaculation, semen contains 300 million sperm (5%) as well as secretions from the bulbourethral glands, the prostate gland and the seminal Urethra Epididymis Testes Scrotum DELIVERY Sperm move through the ejaculatory duct into the urethra, where they can be expelled.
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lecture 13 - Human Reproduction Why learn about...

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