Reproductive System

Question 1

what is reproduction?

Answer 1

union of male and female gametes
each half set of chromosome to form new individual with dull set of chromosome.

Question 2

chromosomal distribution

Answer 2

parents diploid (46 chromosomes) somatic cells

meiotic division

haploid (23 chromosomes) ovum and sperm

fertilise

diploid fertilised in ovum (fetus)

meiosis

offspring with diploid somatic cells.

Question 3

function of male testes

Answer 3

paired oval glands

produce sperm + sex hormone known as testosterone

Question 4

internal structure of testes

Answer 4

-divided into 250-300 lobules
-each lobule has 2-3 coil tubes (seminiferous tubules)
-top of each lobule join + pass into straight tubes then into coiled epididymis.

check notes for more details.

Question 5

leydig cells

Answer 5

synthesis and secretion of testosterone and other androgens.

Question 6

seminiferous tubules
(internal structure of testes)

Answer 6

internal part of testes

smooth muscles wall - contract to move sperm and fluid through tubule

inner lining epithelial cells - controlling formation and development of sperm.

lumune of tubule filled with fluid for development of sperm.

between tubules there is connective tissue - support and contains leydig cells.

Question 7

seminiferous tubules

sertoli cells + spermatogenic cells

(internal structure of testes)

Answer 7

sertoli cells extend from basement membrane to lumen. form tight junctions to form blood testes barrier

why?
-protect developing gametes from blood
-support and protect developing spermatogenic cells.
-release sperm to lumen
-prevent immune response of spermatogenic antigens.

Question 8

spermatogenesis

Answer 8

1.) diploid cells multiply via mitosis
2.)differentiate into primary spermatocyte with diploid cells
3.) under meiosis - secondary spermatocytes each haploid with double strands of chromosome.
4.) undergo second meiosis - four spermatids with haploid cells. single strand chromosomes.
5.) each spermatic becomes sperm

Question 9

sperm morphology

Answer 9

~300 million day/lifetime
48 hours in female tract
adapted for reaching and fertilising egg
head contains DNA. aerosome with enzyme to penetrate egg.
middle contains mitochondria for ATP for energy
tail flagellum for locomotion

Question 10

male sex hormones - androgens

Answer 10

primary sex hormone - testosterone
leydig cells + adrenal glands produce testosterone

androgen production constant with diurnal variation

responsible for: foetal differentiation
development of male urogenital system + have some effects on the brain

after birth, leydig cells inactive and are activated by gonadotropins during puberty. sex organs grow and secondary sec characteristics develop.

Question 11

Penis

Answer 11

contains: - urethra root, body, glans penis. it is a passage for semen and urine.

has three columns of erectile tissue: 2 corpora cavernose and 1 gentral column

glans penis - end of penis covered in foreskin

Question 12

semen

Answer 12

mixture of semen and fluid

60% seminal vesicles
30% prostrate
10% bulbourethral glands.

slightly alkaline, milky and sticky

contains nutrients, clotting proteins and antibiotics to protect sperm

Question 13

effects of testosterone in males

Answer 13

• male secondary sex characteristics develop
  -differentiation of male accessory reproductive organs and maintain their functions
  -opposes oestrogen for breast growth
  -initiation and maintenance of spermatogenesis.
  -required for sex drive
  -bone growth etc.

Question 14

accessory glands

Answer 14

60% seminal vesicles - seminal fluid and fructose sugar. atp + prostaglandins. chemicals for coagulation of semen.

30% prostrate - secrete seminal fluid

10% bulbourethral glands - clear alkaline mucus to buffer + lubricate urethra.