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LU 6 : REPRODUCTION AND BREEDING (REPRODUCTION ADAPTATION IN BIRDS…
LU 6 : REPRODUCTION AND BREEDING
EXPLAIN THE FUNCTIONS OF MALE AND FEMALE SEX ORGAN AND HORMONES
MALE SEX ORGAN AND HORMONES
TESTIS
- produce sperm
(spermatogenesis)
and sex hormones
(steroidogenesis)
ACCESSORY ORGANS
- produces fluids which carries the sperm to the penis
DUCTS
- store and carry sperm and seminal fluids to penis
PENIS
- deposit sperm into vagina
FOLLICULAR STIMULATE HORMONE
- the testis (sertoli cells) to produce
sperm and inhibin
LUTEINIZING HORMONE
- stimulate the testis (Leydig cells) to produce
testosterone
FEMALE SEX ORGAN AND HORMONES
OVARY
- produces ova and hormones
OVIDUCT
- transport of ovum
UTERUS
- implantation and pregnancy
CERVIX
- protects from external disturbance
VAGINA
- organ of copulation
VULVA ORGANS
- external opening to reproductive organs
LUTEINIZING HORMONE
- stimulate
corpus luteum
to produce
progesterone
FOLLICULAR STIMULATING HORMONE
- stimulate
follicle
in the ovary to grow and produces
estrogen
Both
estrogen and progesterone
maintains the uterus and secondary sexual characters and exert feedback control over both
hypothalamus and puititary gland
.
DISCUSS THE MENSTRUATION AND MENSTRUAL CYCLE, FERTILIZATION, PREGNANCY, LACTATION, BIRTH CONTROL
ESTRUS VS MENSTRUAL CYCLE
ESTRUS
•
Estrus
is period of sexual receptivity
•
Metestrus
is a period of corpus luteum formation
•
Diestrus
is a period when corpus luteum is fully functional
•
Proestrus
is period of follicular growth
• Estrus cycle depicts ovarian activity
MENSTRUAL CYCLE
• Characterized by obvious bleeding
• Bleeding is a result of shedding of the vascularised walls of the uterus
• Menstrual cycle depicts uterine events in
large apes and human
FOLLICULAR GROWTH
While in this resting phase they grow in size and became known as
primary follicles
As they grow, they put on a layer of cells called
granulosa cells
, these cells from a
mucopolysaccharide layer
called
zona pellucida
around them. At this stage, they are called
secondary follicle
Around the time birth, the oogonia enters into the prophase of the 1st meiotic division (
oocytes
) and remain in this
resting phase
until puberty
Once a follicle start to grow the final outcome is either
ovulation or atresia
During prenatal stage
-
oogonia
(germ cells) undergo
mitosis
and increase in number
Almost all follicle become
atretic
.
Atresia
involve loss of antrum (cavity containing follicular fluid)
FACTORS INVOLVE IN REPRODUCTION AND BREEDING
HORMONAL CHANGES DURING ESTROUS CYCLE
PHOTO-PERIOD AND BREEDING SEASON
HORMONAL CONTROL OF REPRODUCTION
SOCIAL FACTORS
NUTRITION
TEMPERATURE AND HUMIDITY
REPRODUCTIVE SENESCENCE
REPRODUCTION ADAPTATION IN BIRDS
Altricials
= need parents to survive
Precocials
= able to survive independently
Uniparental
= female only parental strategy
Biparental
= both parents needed
Reproductive success
decline
(altrophy) during non breeding season.
Male:
Paired Testes
and getting
larger
during the breeding season.
Cloacal protuberance
to keep sperm at
optimum temperature
Lack of penis
, hence the brief copulation act
(cloacal kiss)
Nearly all birds species have
1 left ovary and 1 left oviduct
only
2 major benefits
:
Reduces female body size/weight
Increase survival chances of fragile egg
REPRODUCTION ADAPTATION
MARINE ANIMAL
-Use both asexual and sexual modes of reproduction
-Majority have simple uni flagellate sperm and relatively small buoyant egg
-Some have ovotestis (produce male and female gametes)
-Direct sex change (pandalid shrimps, clown, aemone fish)
FRESHWATER ANIMAL
-Very short life cycle
-Rapid turnover of generation
-Reduce larval forms
-More direct development involve larger and yolkier egg (mollusks) or brood pouches (crustacean water flea)
-Unusually large (if larvae persist)
-Protected surface (chitinous covering)
-Direct insemination (save the sperms)
-Protective 'dormant' stage other than shelled eggs
GAMETOGENESIS
OOGENESIS
-Production of egg cells
-begin in ovaries of femle fetus
-Oogonia undergo mitosis in order to build up a large numbers in the ovaries
-These grow up into larger cells called primary oocytes
-Primary oocytes begin meiosis, but stop at Phosphase 1
SPERMATOGENESIS
-Occurs in the seminiferous tubules
-Basement membrane of this tubule contain spematogonia (sperm mother cells)
Spermatogoia divides into primary and secondary spermatocytes and the differentiates to spermatids and finally spermatozoa.
-Once spermatozoa formed, they exist free in the lumen
-semniferous tubules secretes testicular fluid which important in the transport sperm out of testis
-Associated with spermatogonia are Sertoli cells (to support and sustain spermatogonia as they move from basement membrane to lumen)
ONTOGENETIC DIFFERENTIATION AND SEX DETERMINATION
SEX DETERMINATION
A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two sexes. Occasionally, there are hermaphrodites in place of one or both sexes
Sex determination in various animal:
XY sex determination
XO sex determination
ZW sex determination
Haplodiploidy
Environmentally dependent sex-determination
