Wk 1 (recap) Flashcards
Scrotum function
Cools testes
Testis function
Produce sperm and sex hormones
Epididymis function
Mature and store sperm
Ductus deferens function
Transport sperm
Accessory sex glands function
Produce seminal plasma
Penis function
Copulatory organ
Os penis is found in which species?
Cat & Dog
Ovary function
Produce oocytes and sex hormones
Oviduct function
Transport the oocyte
Uterus function
Supports development of the embryo and fetus
Cervix function
Protects uterine environment
Vagina and vestibule function
Copulatory organ, expels the fetus
What type of uteri does the mare have?
Bipartite
1 cervix
Prominent uterine body
What type of uteri does the dog & cat have?
Bipartite
1 cervix
Prominent uterine body
What type of uteri does the ewe have?
Bipartite
1 cervix
Prominent uterine body
What type of uteri do primates have?
Simplex
Bipartite
1 cervix
Prominent uterine body
No horns
What type of uteri do rats, mice and rabbits have?
Duplex
2 cervices
No body
Horns completely seperate
What type of uteri do pigs have?
Bicornuate
1 cervix
Small body
Primordial follicles
Formed before birth
Oocytes arrested at first meiotic division
Primary follicles
Oocytes surrounded by a single layer of follicular cells
Secondary follicles
Oocytes surrounded by more layers of follicular cells
Stimulated by gonadotrophins to produce E2
Tertiary (antral) follicles
Contains a fluid filled cavity (antrum)
Blister-like structure
Producing lots of oestrogen –> about to ovulate
Corpus Luteum
Producing lots of progesterone
Corpus albicans
Corpus luteum heals and forms scar tissue
Thecal cells
Surround and support the follcile
Thecal cells and granulosa cells work together to produce oestrogen
Granulosa cells
Responds to FSH to produce oestrogen, inhibin and follicular fluid
Thecal cells and granulosa cells work together to produce oestrogen
Cumulus oophorus
Promotes oocyte maturation and ovulation
Zygote
Fertilised egg
Embryo
Fertilised egg that has started dividing
The sperm journey
- Sertoli cells
- Seminiferous tubules
- Rete tubules
- Efferent ducts
- Epididymis
- Ductus deferens
- Pelvic urethra
- Penile urethra
The zygote journey
- Primordial follicle
- Primary secondary follicle
- Antral follicle
- Ovulation
- Oviduct
- Fertilisation
- Uterus
What stage should the embryo be at by the time it reaches the uterus?
Blastocyst stage
It will then hatch out of the ZP and attachment will occur
Parturition
brief summary
Fetus signals readiness Placental secretions change from P4 to E2 PGF2alpha secretion increases Oxytocin levels increase Labour induced Fetus expelled
Vegetative stage of an animals life
Animal grows or maintains itself but is not reproductively active
Reproductive phase of an animals life
Animal engages in activity designed to replicate itself
R species
Small body size Short lifespan Short gestation Large litter Rapid rate of development Short birth interval Variable population size (e.g. Drought small population– rain comes – population booms)
K species
Large body size Long lifespan Long gestation Single offspring Slow rate of development Long birth interval Stable population size
Are pigs a K or R species?
Pigs don’t fit either R or K species (characteristics of both)
Reproductive –> vegetative states - Incorporation
Reproductive habits incorporated into vegetative lifestyle phase
E.g. Self fertilising bisexuals
Reproductive –> vegetative states - Seperation
Complete separation of vegetative and reproductive phases
Some individals reproduce and others dont - e.g. bees
Terminal breeding - individuals breed then die e.g. salmon
Reproductive –> vegetative states - Alternation
Switches between vegetative and reproductive lifestyle phases
Most animals and mostly seasonal
Copulation time for rabbits
5-15 seconds
Copulation time for bulls
10 seconds
Copulation time for boars
15-20min
Tend to live in woodlands/forest so can afford to copulate for longer period of time
Copulation time for dogs
5-15 mins (genital lock)
Monogamy
Paired stable mating
e.g. geese
Promiscuity
Indiscriminate mating within a group
E.g. Chimpanzees
Polygamy
Individual has more than than one mate
Polyandry
Female has many males
E.g. bees
Polygyny
Male has many females - e.g. deer and seals
Sexual determination of a female (brief)
No testis determining factor (TDF)
So ovaries develop
No AMH
Paramesonephric ducts become the oviducts, uterus, cervix and part of the vagina
Sexual determination of a male (brief)
Testis determining factor (TDF) present
Testis develop
Sertoli cells secrete anti-mullerian hormone (AMH)
AMH causes degeneration of paramesonephric duct and causes Leydig cells to differentiate
This causes testosterone to be produced and development of male duct system
Freemartinism
Infertile female with a male twin
Typical in cow twins
Female twin is exposed to anti-mullerian hormone (AMH) in blood supply of male twin, preventing or altering development of female tract
Hormones immediately preceding puberty
Pituitary contains Gn’s but they are not secreted in large quantities
Peaks of Gn’s gradually increase closer to puberty
Follicles develop and secrete low levels of E2 but ovulation does not occur
Low level spermatogenesis may occur
Significant events surrounding puberty
Physiological maturation:
Easing of negative feedback
Development of positive feedback in the female
Physical maturation:
Growth spurt (influence of steroids)
Development of sex organs
Production of gametes
Behavioural maturation:
Sexual behaviour and receptivity
Indicators of puberty in males
Behavioral traits- mounting and ejaculation
First ejaculation (voluntary or spontaneous)
Spermatozoa present in urine and/or ejaculate
Ejaculate contains threshold numbers of spermatozoa
Male is capable of coitus and ejaculating sufficient good quality spermatozoa to result in fertilization
Indicators of puberty in females
Commencement of cycling – first oestrus
First ovulation – may be silent
Physical maturation to be able to support pregnancy without negative effect on mother
Capable of ovulation of an ova which can be fertilized and carried to term (related to body size and involved development of whole tract)
Initiation of puberty
Pineal gland secretes melatonin; melatonin stimulates GnRH secretion
Manipulation of melatonin levels can cause precocious puberty and influence of glucose and/or leptin (think threshold of blood glucose or leptin that trigger puberty- means size of animal relates to puberty – growing animal needs energy blood sugar/fat low – mature adult can increase blood sugar/fat levels)
Malnutrition and puberty
Under-nutrition retards puberty – protective mechanism against pregnancy
Severe or prolonged malnutrition leads to a permanent growth check (and potential subfertility)
Puberty can be advanced by heavy feeding (except in pigs)
Use of hormones to artificially induce puberty
Stimulation of follicular growth can be achieved with exogenous FSH or equine chorionic gonadotropin (eCG)
Ovulation can be initiated with LH or human chorionic gonadotropin (hCG) – similar effect to LH except in primates
Melatonin can be administered to trigger increased production of GnRH, leading to an endocrine cascade that triggers puberty
Can only be done close to time of normal puberty when secondary organs (e.g. uterus) are sufficiently matured
Reproductive senescence (females)
Reduction in number of breeding opportunities
Polyoestrous animals – more silent heats
Monoestrous animals – increased interval between oestrous cycle
Decreased conception rates
Decreased litter size
Increased prenatal losses, dystocia, mismothering and reduced lactation
Increased in chromosomal disorders e.g. Downs Syndrome
Increased spontaneous abortion
Increased aborted fetuses with chromosomal disorders
Reproductive senescence in males
Males generally fertile until death - continue to produce spermatozoa but fertility does decline
BUT
May become physically incapacitated and unable to mount
There is a gradual decline in sexual interest from peri-pubertal stage
