Presentation is loading. Please wait.

Presentation is loading. Please wait.

Male repro system functions

Similar presentations

Presentation on theme: "Male repro system functions"— 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 7th 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


6 Structure/Functions (3)
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

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


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


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


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


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




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


31 Hormonal Control of Ovulation

32 Female hormone functions



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

Download ppt "Male repro system functions"

Similar presentations

Ads by Google