reproductive system Flashcards
– saclike structure containing the testes
- divided into left and right internal compartments by an incomplete CT septum
- external composition: skin
- internal composition: dartos muscle (layer of smooth muscle) and layer of loose CT
A. SCROTUM
male gonads
- oval organs about 4-5 cm long within scrotum
- outer part: thick, white CT capsule
- extensions of capsule divide testes into 250 cone-shaped lobules which contain seminiferous tubules
B. TESTES –
– where sperm cells develop
SEMINIFEROUS TUBULES
– endocrine cells in the delicate CT surrounding seminiferous tubules
-secrete testosterone
INTERSTITIAL OR LEYDIG CELLS
– large, extend from periphery to the lumen of seminiferous tubules
-nourish germ cells and produce a number of hormones
SUSTENTACULAR OR SERTOLI CELLS
formation of sperm cells
SPERMATOGENESIS –
most peripheral germ cells, divide through mitosis
Spermatogonia –
– divide by meiosis and become sperm cells
- contains 46 chromosomes
- passes through Meiosis I to produce 2 secondary spermatocyte
Primary spermatocytes
– undergoes Meiosis II to produce 2 smaller cells or spermatids each having 23 chromosomes
Secondary spermatocyte
undergo structural changes after the Meiosis II to become sperm cells
-much cytoplasm are eliminated
Spermatids –
contains enzymes released during the process of fertilization
-enzymes are necessary for the sperm cell to penetrate the oocyte or egg cells
Acrosome –
developing—- are located around lumen of seminiferous tubules
- heads directed toward sustentacular cells
- tails directed toward lumen
Sperm cells –
– comma-shaped structure on the posterior side of testis
- SC continue to mature here
- SC develop capacity to swim and ability to bind to the oocyte
- SC taken directly from testes are not capable of fertilizing oocytes
EPIDIDYMIS
–final changes in SC, occur after ejaculation of semen into vagina prior to fertilization
CAPACITATION
about 45 cm long, emerges from epididymis and ascends along the posterior side of the testis to become associated with BV and nerves (spermatic cord)
- extends through abdominal wall by way of inguinal canal
- ampulla of the—— enlargement just before reaching the porstate gland
- wall contains smooth muscle which contracts in peristaltic waves to propel sperm cells from the epididymis through the ——-
- Ductus Deferens or Vas Deferens –
PARTS OF SPERMATIC CORD
- Ductus deferens
- Testicular artery and veins and nerves
- Lymphatic vessels
- 2 CT sheaths
– sac shaped gland near the ampulla of the ductus deferens
- glands consisting of many saclike structures located next to the ampulla of ductus deferens
- each about 5 cm long
SEMINAL VESICLE
have both glandular and muscular tissue
- surrounds urethra and 2 ejaculatory ducts
- cells lining partition secrete prostatic fluid
- 10 -20 short ducts carry fluid to prostatic urethra
• Prostate Gland –
– pair of small mucus secreting glands near base of penis
- pea sized, decrease with age
- single duct from each gland enters urethra
• Bulbourethral or Cowper gland
– formed by the ducts from the seminal vesicle and the ampulla of vas deferens at the prostate gland
-each extends into the prostate gland and ends by joining the urethra within the prostate gland
EJACULATORY DUCT
– extends from UB to distal end of penis
- passageway for both urine and male reproductive fluids but they do not exit at the same time
- while MRF are passing through urethra, sympathetic reflex causes internal urinary sphincter to contract, keeping semen from passing into urinary bladder, preventing urine from entering urethra
URETHRA
male organ of copulation,
- functions in the transfer of sperm cells from M to F
- contains 3 columns of erectile tissue
- shaft: loosely attached to CT
- skin is firmly attached at the base of the glans penis, and a thinner layer of skin covers glans penis (prepuce)
penis
2 columns of erectile tissue that form the dorsal side of penis
Corpora cavernosa –
third smaller column forming the ventral
Corpus spongiosum –
• – covers glans penis
Prepuce or foreskin
– mixture of sperm cells and secretions from male reproductive glands
- 60% seminal vesicles, prostate gland 30%, 5% testes, 5% bulbourethral gland
- normal semen volume: 2-5 ml with 100 M sperm cells
semen
• Mucous secretion which lubricates urethra, help neutralize contents of normally acidic urethra, provide small amount of lubrication during intercourse, help reduce acidity of vagina
Secretions of bulbourethral and mucuous glands
• Sperm cells + small amount of fluid
Testicular secretions
- Thick mucuslike
- Contains sugar fructose
- Contains nutrients to nourish sperm cells
- Contains proteins that weakly coagulate after ejaculation and enzymes
- Prostaglandins –
Seminal Vesicle secretions
high conc. in seminal vesicle secretions, cause contractions of female reproductive tract to help transport sperm through tract
Prostaglandins –
- Thin and milky and alkaline
- Help neutralize acidic urethra, testes secretions, seminal vesicles and vagina
- Have proteolytic enzymes – break down coagulated proteins of seminal vesicles, make semen more liquid
- Alkalinity is important for normal sperm cell function
prostate gland secretions
o Optimal sperm cells need ph of
6.0-6.5
mechanism for development of reproductive structures, 2nd sex characterisitcs, spermatogenesis, some aspects of intercourse
hormonal
mechanism for control of sexual act, expression of sexual behavior
Neural
surgical removal of prepuce, for hygienic purposes too
Circumcision –
causes cells in anterior pituitary to secrete LH and FSH
GnRH –
binds to Leydig cells to secrete testosterone
LH –
binds to Sertoli cells to promote sperm cell development
-increases inhibin secretion
FSH –
*For GnRH to stimulate LH and FSH release, pituitary gland must be exposed to a
series of brief increases and decreases in GnRH.
sequence of events by which a child is transformed into a young adult
puberty
major male hormone secreted by testes
- influences reproductive organs and nonreproductive structures
- causes enlargement of and differentiation of male genitals and reproductive duct system
- necessary for spermatogenesis and development of male secondary sex characteristics
- maintains adult structures after puberty
TESTOSTERONE-
structural and behavioral changes other than in reproductive organs
-develop at puberty, distinguish M from F
Secondary sex characteristics –
o hair distribution & growth
o fat distribution
o skeletal muscle growth
o changes in larynx
Secondary sex characteristics –
required for normal sexual behavior
- enters certain cells w/in brain to influence functions
- blood levels remain relatively constant from puberty until age 40
Testosterone –
– series of reflexes that result in penis erection, mucus secretion into urethra, emission and ejaculation
MALE SEX ACT
movement of sperm, mucus, seminal vesicle and prostatic secretions into the 3 parts of urethra
Emission
forceful expulsion of secretions that have accumulated in urethra to exterior
Ejaculation –
intense sensation interpreted as pleasurable, closely related with ejaculation (but are separate functions and do not always occur simultaneously)
Orgasm or climax –
occurs after ejaculation
- penis becomes flaccid
- overall feeling of satisfaction
- inability to achieve erection and 2nd ejaculation
o Resolution –
ejaculation while sleeping
-common in young males, associated with dreaming
o Nocturnal Emission –
1st major component of male sex act
- parasym AP cause arteries of the erectile tissues to dilate
- blood fills sinusoids (small venous sinuses), compresses veins, reduces blood flow to penis
- ↑ blood pressure cause erectile tissue to become inflated and rigid
ERECTION –
impotence, failure to achieve erection
ERECTILE DYSFUNCTION (ED) –
Causes of ED
o Reduced testosterone secretion
o Defective stimulation of erectile tissue
stimulated by sympathetic AP that originate in lumbar region of spinal cord
-accumulation of semen in urethra
EMISSION –
before it, vas deferens begin to contract rhythmically, propelling sperm cells and testicular fluids from epididymis through vas deferens
- result from contractions of smooth muscle in urethra wall and skeletal muscles surrounding penis base
- forcing semen out of urethra
- increased muscle tension
EJACULATION –
– reduced or diminished infertility
INFERTILITY
CAUSES OF INFERTILITY
:
o Low sperm cell count (belowe 20 M sc per ml)
o Abnormal sperm cell structure
o Reduced sperm cell motility (caused by presence of antibodies)
collection of several ejaculation, concentration of sperm cells, insertion into the female RT
Artificial Insemination –
