أحياء لغات -Reproduction in Human1 للصف الثالث الثانوى 2016

Reproduction in Human Beings

:The Male Genital System

.Man belongs to class mammalia in which the embryo develops inside the uterus till birth *

.The human ova are small and nearly devoid of yolk *

  .The number of offspring is few, due to parental care *

.Man shows a high degree of care, because young’s requires several years of raising *

 .God provide man mental progress to be superior over other creatures *

: The Male Genital System

The structure of male reproductive system

  It consists of two testes, each testis leads a group of tubules called  epididymis which connected to the vasdeferens that lead to urethera, male reproductive system contains accessory glands

:The structure of Male Genital System

:a) The two testes

  .The testis lies outside the body in the scrotal sac

  The embryo testis descend down into the scrotal sac during the last months of pregnancy such a position prepares a condition cooler than the body temperature to be suitable for spermatogenesis

 ( production of sperms)

  Whenever a testis fails to descend down into the scrotum, spermatogenesis does not occur, causing infertility sterility

:The importance of the testis

.The production of sperms -

.The secretion of testosterone hormone, which causes the male secondary sexual character -

:b) The two epididymis

.Each testis leads to a group of cumulated tubes called epididymis, which fuses with the vas deferens

:c) The two-vas deferenses

.Each vas deferens transports sperms from the epididymis to the seminal vesicle

:d) The two seminal vesicles

.In which the sperms are stored until they leave the body

:e) Prostate gland and Cowper’s glands

(They secrete a sugary fluid (which feed sperms

 They secrete an alkaline fluid to neutralize the acidity of the urethra just before the sperms, because the neutral medium suits of the sperms

:f) The penis

  .It is an organ consists of a fiber tissue, through which the urethra passes

  .Each of the urine and the sperms pass through the urethra individually

  :The Male Genital System

The function of male reproductive  system

.Production of sperms

.Secretes male hormones to develop the secondary sex characters

Male secondary sexual characters

.The voice becomes deep

.Muscles grow stronger

.Growth of facial hair

:The Male Genital System

:Study of a T.S. of testis *

   The testis is built up of seminiferous tubules among them these are interstitial cells which secrete the testosterone hormone

  .Inside each tubule these are sertoli cells which secrete fluid to feed the sperms inside the testis

  .It is supposed that, they gave also immunization function

  .Each tubule is lined internally with primary germ cells (diploid) (2N) they are divided to form sperms

Phases of spermatogenesis

  :Multiplication phase

     The primary germ cells(2N) are divided by mitosis several times

   (to produce a great number of spermatogonia cells (2N

:Growth phase

     The spermatogonia cells store an amount of food to change into

     .primary spermatocytes

  .Phases of spermatogenesis

:Maturation phase

     (The primary spermatocytes (2N

are divided by meiosis (1) to produce

secondary spermatocytes (N) which

are divided by meiosis (2) to produce

(spermatids (1N

:Metamorphosis phase

  .The spermatids are converted into sperms

Structure of sperm

It consists of head, neck, midpiece & tail

:a) The head

It contains nucleus {(1N) = 23 chromosomes} & acrosome

The function of acrosome

It secretes the hyaluronic enzyme that dissolves a part of

.the ovum membrane, to facilitate its penetration process

:b) The neck

It contains two centrioles, which play an important

.role in the division of the fertilized ovum

:c) The midpiece

.It contains mitochondria to energy for movement

:d) The tail

 .It consists of an axis, which ends with caudal piece to help the sperm to move

The Function of the human female genital system

.Its Function

The production of  mature ova

The secretion of famale sex hormones

Providing a safe place for fertilization

Providing a safe place for embryo dvelopment till birth

The number of mature ova

During childhood, each ovary contains *

 several thousands of ova in different

.development stages of

After maturity about 400 only will mature *

  (They consumed during 30 years (active reproductive life =fecundity years *

  *The ovaries are alternated the production of one mature ovum each month.                              *  It secretes the maturation hormones for regulating menstrual cycle and embryo development

  The organs of this system lie behind the urinary bladder and connected the with the pelvic region by elastic ligaments

  .The pelvic region is expansion during pregnancy

.The  structure of the human female genital system

Its structure

  It consists of two ovaries, two oviducts, the uterus and the vagina

:a) The two ovaries

Each ovary has an oval shape equals in size a peeled almond

They lie on the sides of the pelvic cavity

(b) The two fallopian tubes (oviducts

  Each Fallopian tube has a funnel shaped

opening facing one of the to ovaries

 to insure the fall of ovum in it

  Each Fallopian tube is provided with

        finger like protrusions and cilia to direct

        the received ovum toward the uterus

:c) Uterus

  .It is an elastic muscular sac-like organ

  .It lies in the pelvic cavity

  .It has a thick muscular strong wall, lined with a glandular membrane

  .The uterus is ended with the cervix which opens to the vagina

  .The embryo is formed inside the uterus for nine months

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