BI513 Human Physiology and Disease
Reproduction and Development
Male Reproduction
Female Reproductive System
Procreation, Pregnancy and Parturition
Female Reproductive System II
Investigations of Infertility
Investigations of Infertility II
Reproduction and Development Overlay
Muscle Physiology
Muscle Physiology II
Cardiac and Smooth Muscle
Skeletal Muscle and Muscle Systems
Muscle Disease
Cells of The Nervous System
Peripheral Nervous System
Disorders of The Nervous System
Problem-solving Workshop
Disorders of the Nervous System II
Sensory Systems
Gustation, Olfaction and Vision
The Eye and Vision
The Ear and Hearing
,Reproduction and Development
Sexual development
- Creates unique individuals.
- Reshuffles genetic composition.
o Advantageous genes.
o Sexual dimorphism (dioecy)
▪ Having male and female reproductive organs in separate
individuals.
▪ Having the male and female reproductive organs in separate
individuals.
Purpose of sexes
- Resource allocation
o The idea that organisms are limited in resources and so will have a trade-
off in the activities they can complete.
o More time spent in producing one type of gamete.
- Avoidance of inbreeding.
Delayed sexual maturity
- Avoids overpopulation.
- Ensure ability to cope with child care.
Sex-determining factors
- Temperature.
- Chromosomes.
- Genic mechanisms
o The SRY gene encodes for the sex-determining region ‘Y’ protein, which
is involved in male sexual development. The SRY protein acts as a
transcription factor that kickstarts the development of testes and
prevents development of female reproductive structures.
o The SRY gene encodes for testis-determining factor (TDF).
Intracytoplasmic sperm injection
- Treatment of male infertility by injection of a single sperm into the egg.
Oogonia / spermatogonia
- Males
o Seminiferous tubules are the site of sperm production and contains
Sertoli and Leydig cells. Spermatogonia are germ cells that form sperm
through meiosis.
Spermatogonia ➡️ 1o spermatocyte ➡️ 2o spermatocyte ➡️ spermatid ➡️
spermatozoa.
o Diploid up until secondary spermatocyte, where it becomes haploid.
64 DAYS CHROMOSOMES CHROMATIDS
, SPERMATOGONIA 46 2
1O SPERMATOCYTE 46 2
2O SPERMATOCYTE 23 2
SPERMATID 23 1
SPERMATOZOA 23 1
- Females
o Oogonia ➡️ 1o oocyte ➡️ mitosis arrests until puberty ➡️ 2o oocyte.
o Meiosis continues until sister chromatids separate, and then stops again.
Fertilisation must occur or else meiosis never goes to completion. The
egg then disintegration.
Semen
- Seminal fluid is made up of secretions from the testes and epididymis, prostate,
seminal vesicles and the bulbourethral gland.
- Composition
o Sperm, mucous, water, buffers, fructose, citric acid, vit. C, carnitine,
enzymes, zinc, prostaglandins.
Reproduction: hypothalamus and anterior pituitary
- Hypothalamus: gonadotropin-releasing hormone.
- Anterior pituitary gland: FSH and LH.
Hormonal control of reproduction
- Leydig cells (LH)
o Leydig cells lie between tubules and are cellular. They make and secrete
testosterone in response to luteinising hormone from the ant. pituitary
gland. They have pale cytoplasm as they contain many cholesterol-lipid
droplets. Cholesterol is used in the synthesis of testosterone.
- Sertoli cells (FSH)
o Sertoli cells are epithelial cells of the seminiferous tubules. They provide
nutrients for male gametogenesis. Sertoli cells support the germ cell
progenitors, such as spermatogonium. They also produce testicular
fluid, translocate differentiating cells to the lumen and phagocytose
degenerating germ cells.
- Gonadotropin-releasing hormone
o The hypothalamus secretes GnRH. GnRH controls the secretion of
gonadotropins (LH and FSH) from the ant. pituitary gland.
▪ FSH: activate/maintain gametogenesis.
▪ LH: activate secretion of steroid sex hormones from endocrine
cells.
▪ GnRH is pulsatile so that the anterior pituitary does not lose
sensitivity when conc. are high (1-3 hours).
- Activins and inhibins
o The gonads can influence their own development. Ovaries and testes
can both secrete peptide hormones that act on the pituitary.
Reproduction and Development
Male Reproduction
Female Reproductive System
Procreation, Pregnancy and Parturition
Female Reproductive System II
Investigations of Infertility
Investigations of Infertility II
Reproduction and Development Overlay
Muscle Physiology
Muscle Physiology II
Cardiac and Smooth Muscle
Skeletal Muscle and Muscle Systems
Muscle Disease
Cells of The Nervous System
Peripheral Nervous System
Disorders of The Nervous System
Problem-solving Workshop
Disorders of the Nervous System II
Sensory Systems
Gustation, Olfaction and Vision
The Eye and Vision
The Ear and Hearing
,Reproduction and Development
Sexual development
- Creates unique individuals.
- Reshuffles genetic composition.
o Advantageous genes.
o Sexual dimorphism (dioecy)
▪ Having male and female reproductive organs in separate
individuals.
▪ Having the male and female reproductive organs in separate
individuals.
Purpose of sexes
- Resource allocation
o The idea that organisms are limited in resources and so will have a trade-
off in the activities they can complete.
o More time spent in producing one type of gamete.
- Avoidance of inbreeding.
Delayed sexual maturity
- Avoids overpopulation.
- Ensure ability to cope with child care.
Sex-determining factors
- Temperature.
- Chromosomes.
- Genic mechanisms
o The SRY gene encodes for the sex-determining region ‘Y’ protein, which
is involved in male sexual development. The SRY protein acts as a
transcription factor that kickstarts the development of testes and
prevents development of female reproductive structures.
o The SRY gene encodes for testis-determining factor (TDF).
Intracytoplasmic sperm injection
- Treatment of male infertility by injection of a single sperm into the egg.
Oogonia / spermatogonia
- Males
o Seminiferous tubules are the site of sperm production and contains
Sertoli and Leydig cells. Spermatogonia are germ cells that form sperm
through meiosis.
Spermatogonia ➡️ 1o spermatocyte ➡️ 2o spermatocyte ➡️ spermatid ➡️
spermatozoa.
o Diploid up until secondary spermatocyte, where it becomes haploid.
64 DAYS CHROMOSOMES CHROMATIDS
, SPERMATOGONIA 46 2
1O SPERMATOCYTE 46 2
2O SPERMATOCYTE 23 2
SPERMATID 23 1
SPERMATOZOA 23 1
- Females
o Oogonia ➡️ 1o oocyte ➡️ mitosis arrests until puberty ➡️ 2o oocyte.
o Meiosis continues until sister chromatids separate, and then stops again.
Fertilisation must occur or else meiosis never goes to completion. The
egg then disintegration.
Semen
- Seminal fluid is made up of secretions from the testes and epididymis, prostate,
seminal vesicles and the bulbourethral gland.
- Composition
o Sperm, mucous, water, buffers, fructose, citric acid, vit. C, carnitine,
enzymes, zinc, prostaglandins.
Reproduction: hypothalamus and anterior pituitary
- Hypothalamus: gonadotropin-releasing hormone.
- Anterior pituitary gland: FSH and LH.
Hormonal control of reproduction
- Leydig cells (LH)
o Leydig cells lie between tubules and are cellular. They make and secrete
testosterone in response to luteinising hormone from the ant. pituitary
gland. They have pale cytoplasm as they contain many cholesterol-lipid
droplets. Cholesterol is used in the synthesis of testosterone.
- Sertoli cells (FSH)
o Sertoli cells are epithelial cells of the seminiferous tubules. They provide
nutrients for male gametogenesis. Sertoli cells support the germ cell
progenitors, such as spermatogonium. They also produce testicular
fluid, translocate differentiating cells to the lumen and phagocytose
degenerating germ cells.
- Gonadotropin-releasing hormone
o The hypothalamus secretes GnRH. GnRH controls the secretion of
gonadotropins (LH and FSH) from the ant. pituitary gland.
▪ FSH: activate/maintain gametogenesis.
▪ LH: activate secretion of steroid sex hormones from endocrine
cells.
▪ GnRH is pulsatile so that the anterior pituitary does not lose
sensitivity when conc. are high (1-3 hours).
- Activins and inhibins
o The gonads can influence their own development. Ovaries and testes
can both secrete peptide hormones that act on the pituitary.
