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Male repro system functions Testes- produce sperm & male sex hormone- testosterone Ducts – transport, store, & assist in maturation of sperm Accessory.

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Presentation on theme: "Male repro system functions Testes- produce sperm & male sex hormone- testosterone Ducts – transport, store, & assist in maturation of sperm Accessory."— Presentation transcript:

1 Male repro system functions Testes- produce sperm & male sex hormone- testosterone Ducts – transport, store, & assist in maturation of sperm Accessory sex glands- secrete most of liquid portion of semen Penis- contains urethra passageway for ejaculation of semen excretion of urine

2 Male repro anatomy

3 Functions of each structure Scrotum- “bag” supporting structure for testes loose skin & superficial fascia hangs from root of penis Testes- paired oval glands develop near kidneys & descend into scrotum in latter half of 7 th fetal month Sperm produced in seminiferous tubules Adjacent to seminiferous tubules are Leydig cells -secrete testosterone.

4 Structure/Functions (2) Epididymis- lies along posterior border of each testis each consists of tightly coiled ductus epididymis where sperm motility ↑ over day pd ductus stores & helps propel sperm by peristaltic contraction of it smooth muscle Sperm may be stored for a month or more

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6 Ductus deferens or vas deferens-  18 in stores sperm, can remain viable several months sperm not ejaculated are reabsorbed (as can happen in epididymis) Cut during vasectomy Ejaculatory ducts-  1 in, formed by union of seminal vesicle & ampulla of vas deferens eject sperm & seminal vesicle secretions just before ejaculation - powerful propulsion of semen from urethra to exterior of body Structure/Functions (3)

7 Structure/functions (4) Urethra- shared terminal duct of reproductive & urinary system Passes thru: prostate gland (prostatic urethra) urogenital diaphragm (membraneous urethra) penis (spongy urethra) Penis- passageway for ejaculation of semen & excretion of urine

8 Glands (1) Seminal vesicles- lies posterior to urinary bladder, anterior to rectum Function: secrete an: alkaline (neutralize acidic environment of male urethra), viscous fluid that contains fructose (ATP production), prostaglandins (contribute to sperm motility & viability) may also stimulate: muscular contraction in female reproductive tract clotting proteins About 60% of volume of semen

9 Glands (2) Prostate gland- inferior to urinary bladder & surrounds prostatic urethra Secretes milky fluid that contains: 1. Citric acid- used in ATP production 2. Acid phosphatase- function unknown 3. Proteolytic enzymes- pepsinogen, lysozyme, amylase, and hyaluronidase About 25% volume of semen

10 Glands (3) Bulbourethral (Cowper’s) glands- inferior to prostate on either side of membraneous urethra During sexual arousal secrete an alkaline substance that protects passing sperm by neutralizing acids from urine in urethra Also secrete mucus- lubricating end of penis & lining urethra to ↓ # of sperm damaged during ejaculation

11 Descent of Testes In both sexes, gonads originate in lumbar region & descend caudally during fetal development In male fetus, testes descend toward scrotum, followed by their blood vessels & nerves testes require a cool location for sperm formation testes reach pelvis near inguinal region in month 3 testes proceed no further until month 7, when they suddenly & quickly pass thru the inguinal canal & enter the scrotum

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13 Parts of spermatozoan Head- contains nuclear material & acrosome Acrosome- dense lysosome-like body in head of sperm cell contains enzymes that facilitate penetration of sperm cell into secondary oocyte Midpiece- contain numerous mitochondria provides ATP for locomotion Tail- typical flagellum propels sperm

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15 Gametes are haploid Haploid- (n) having half the # of chromosomes characteristically found in somatic cells of an organism Sperm Oocyte Diploid- (2n) having the # of chromosomes characteristically found in the somatic cells of an organism

16 Meiosis vs. Mitosis Meiosis- cell division during production of gametes 2 successive nuclear divisions resulting in daughter cells with haploid number chromosomes 2n  n Mitosis- division of nucleus that ensures each new daughter nucleus has same number & kind of chromosomes as original parent nucleus Process includes the 2 full sets of chromosomes sent into 2 separate & equal nuclei Daughter cells have diploid number of chromosomes 2n  2n

17 Maturation of sperm

18 Hormonal control of spermatogenesis

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20 Hormone producing cells Sertoli cells- supporting cell of seminiferous tubules secretes fluid for supplying nutrients to sperm Secrete hormone inhibin phagocytizes excess cytoplasm for spermatogenic cells mediates effects of FSH & testosterone Secrete Mullerian–inhibiting substance during fetal development Leydig cells- secretes testosterone located in CT between seminiferous tubules

21 Negative feedback loop for testosterone

22 Female repro structures Ovaries produce 2° oocytes and hormones Estrogens, progesterone, inhibin, relaxin Uterine tubes transport 2° oocyte to uterus. Also, site of fertilization Uterus- implantation, fetal development, labor Vagina receives penis during intercourse, passageway for childbirth Mammary glands- synthesize, secrete, eject milk for nourishment of newborn

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24 Oogenesis During fetal development, primordial germ cells migrate: yolk sac  ovaries Germs cells in ovary = oogonia Are diploid Most degenerate– atresia Few develop into primary oocytes which enter prophase I of meiosis during fetal development do not complete until puberty –1° oocyte surrounded by follicular cells= primordial follicle

25 Primary oocyte development 200,000– 2,000,000 oocytes/ovary at birth 40,000 still present at puberty  400 will mature and ovulate Monthly: FSH & LH stimulate development of several primordial follicles, typically only one matures enough to be ovulated Primary follicle  secondary follicle  Graafian follicle  follicle ruptures = ovulation See figure 28.13

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29 Oogenesis One female gamete (haploid) forms from one oogonium (diploid) How many male gametes are formed from one diploid spermatogonium? Table 28.1 summarizes

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31 Hormonal Control of Ovulation

32 Female hormone functions

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35 Human sexual response 4 stages: Excitement = arousal, ParasympNS causes vasocongestion HR & bp , skeletal muscle tone, hypervent Plateau– excitement sustained intensely, sex flush=redness of face & chest Orgasm- briefest, ejaculation, muscular contractions in both sexes. SympNS causes smooth muscle contraction of genitals Resolution- relaxation & return to unaroused state


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