why sexual reproduction? · male reproductive system scrotum = sac that testes are suspended in the...
TRANSCRIPT
![Page 1: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/1.jpg)
![Page 2: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/2.jpg)
Why Sexual Reproduction?
�continuity of the species
�genetic variation
�Gametes (egg or sperm) are produced in the primary sex organs or gonads (ovaries or testes)
�Male and female parts originate from same tissues and same area of the abdomen
![Page 3: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/3.jpg)
![Page 4: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/4.jpg)
The Male Reproductive System
![Page 5: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/5.jpg)
Male Reproductive System�scrotum = sac that testes are suspended in
![Page 6: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/6.jpg)
The Path of Sperm:
1.testes= male gonads
� containing (~250 m) tightly coiled seminiferoustubules
![Page 7: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/7.jpg)
![Page 8: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/8.jpg)
The Path of Sperm:
1.testes= male gonads
� containing (~250 m) tightly coiled seminiferous
tubules
� Tubules produce mature sperm cells by meiosis - called
spermatogenesis
� has interstitial cells that produce testosterone
� before puberty, the tubules are solid cords →become
hollow and start to function with puberty
![Page 9: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/9.jpg)
![Page 10: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/10.jpg)
2. epididymis – place of sperm maturation (including gaining motility) & storage of sperm
� tightly coiled tubules (~5-6m long) just
outside the testes
3. vas deferens = tube takes sperm from epididymis to urethra (through penis)
� First part stores sperm
![Page 11: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/11.jpg)
![Page 12: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/12.jpg)
Path (cont’d)
4. Urethra – carries both urine and semen
� During ejaculation, the bladder is closed off so no urine comes out
![Page 13: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/13.jpg)
Contributory Glands� secrete products that contribute to semen
production
Semen = seminal fluid + sperm
A.Seminal vesicles = between bladder & rectum &
joins vas deferens
� Releases fluid containing
1. Nutrients for sperm (fructose)
2. Prostaglandins – triggers uterus contractions &
aid in sperm movement
![Page 14: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/14.jpg)
Glands (cont’d)B. prostate gland – just below bladder
� Adds an alkaline (base @ pH 7.5) buffer to
protect sperm against acidity of vagina
C. Cowper’s or Bulbourethral gland – just below
prostate
� Adds lubrication for sperm → better
movement
Note: End of glands
![Page 15: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/15.jpg)
�Penis - made up of erectile tissue which fills with blood when excited (an erection)
= transfers sperm to female
�The main difference between male and female systems:
�Males release gametes during sexual activity while females release only during a monthly cycle
![Page 16: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/16.jpg)
Penis Anatomy
![Page 17: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/17.jpg)
![Page 18: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/18.jpg)
Sperm� Acrosome - contains
enzymes to help penetrate
the egg
� Nucleus – transmit genetic
information (23 chromosomes)
� Mitochondria (spiral) to
provide energy for tail
movement
� Tail – swim
![Page 19: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/19.jpg)
Testosterone
�hormone produced mainly by interstitial
cells of the testes
� responsible for primary and secondary sex
characteristics
![Page 20: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/20.jpg)
![Page 21: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/21.jpg)
PRIMARY SECONDARY
Development of vas
deferens and other ducts
Deepening of voice
Maturation of external
genitalia
Distribution of hair
Sperm production Muscle growth
![Page 22: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/22.jpg)
Control of Testosterone
� GnRH (fr. Hypothalamus)= (gonadotropic
releasing hormone) causes anterior pituitary to
release LH and FSH
� LH (luteinizing hormone) - stimulates interstitial cells
(testes) to produce testosterone
� FSH (follicle stimulating hormone) – targets
seminiferous tubules – stimulates sperm production
� All are regulated by negative feedback
![Page 23: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/23.jpg)
Ho
rmo
na
l C
on
tro
l o
f T
est
es
![Page 24: Why Sexual Reproduction? · Male Reproductive System scrotum = sac that testes are suspended in The Path of Sperm: 1. testes = male gonads containing (~250 m) tightly coiled seminiferous](https://reader034.vdocuments.site/reader034/viewer/2022042621/5f51b9088f46b811f311f566/html5/thumbnails/24.jpg)