Unit 2 - Reproduction and Development Flashcards
Primary Sex Characteristics )
(M)
Structured directly involved in forming and transporting gametes (sex cells/ sperm).
Secondary Sex Characteristics (M)
Develop in males due to testosterone, but are not directly involved in reproduction.
—>Large larynx (lower voice), facial and body, muscle development.
Testes
Contains long coiled tubes called SEMINIFEROUS TUBULES.
–>ST is where spermatogenesis occurs (creation of cells).
Sperm Structures
1) Head
2) Acrosome
3) Middle Piece
4) Long tail
Interstitial Cells (Ley dig Cells)
Cells between tubules, produce testosterone.
Sertoli Cells
Large pyramidal cells with seminiferous tubules.
–>They help develop and nourish the sperms.
Head
Contains the nucleus that has DNA as well as Acrosome.
Acrosome
Contains enzymes used to break down outer layer of the egg, so DNA can enter the egg.
Middle Piece
Contains lots of mitochondria to produce energy (ATP) for movement.
Long tail
Moves sperms forward.
Testes During Puberty
They descent.
–> Proper spermatogenesis needs temperature slightly lower than body temperature.
–> If testes don’t descend, can lead to sterility (unable to produce).
Pathway of Sperm
Testes –> Epididymis –> Vas (Ductus) Deferens –> Ejaculatory Duct (Prostate Gland, Cowper’s Gland, Seminal Vesicles) –> Urethra (within the penis).
Seminal Fluid
1) Sperm
2) Fluid from seminal vesicles containing sugars and used by sperm for ATP production.
3) Secretions from prostate gland, Cowper’s (bulbourethral) gland, alkaline to neutralize acidity of urine and acidity of female reproductive tract.
Primary Sex Characteristics (F)
Produce and transport gametes (eggs).
Gonads (F)
OVARIES, produce eggs and sex hormones (estrogen and progesterone).
Secondary Sex Characteristics (F)
Less facial/body hair, breasts, higher voice, wider hips, less muscle development.
–> Caused by estrogen.
Ovaries
Site of Oogenesis (production of eggs).
–>Contain specialized structure called follicles, each follicle contains one developing egg.
Ovulation
Once a month, one of the ovaries will develop an egg inside a follicle and release the egg into the reproductive tract.
Eggs (Ovum)
Cannot move.
–> Much larger than the sperm by about 20x because it contains all the resources (cytoplasm, organelles) for potentially developing embryo.
–> Contains 23 chromosomes (half a human’s DNA, sperm has the other half).
Gonads (M)
Structures which forms gametes, produce sex hormones.
Male:
—>Testes is responsible for production of sperm and testosterone.
Fimbriae
Sweeps egg into oviduct.
Oviduct (Fallopian Tube)
Carries egg from ovaries to uterus.
–> Site of fertilization.
Uterus (Womb)
Large, pear-shaped organ which holds and nourishes developing fetus.
–> If egg is fertilized, it will implant into inner lining of uterus.
–> If egg is NOT fertilized, it will exit the body through menstruation.
The Uterus (2 Major Tissues)
1) Outer Muscle Layer
2) Inner Glandular Layer (ENDOMETRIUM)
Endometrium
Contains many blood vessels to nourish developing embryo.
–> Thickness changes throughout menstrual cycle.
–> If fertilization does not occur, endometrium and unfertilized egg is shed.
Cervix
Opening at bottom of uterus.
Vagina
Birth canal, leading from uterus to outside of body.
Vulva
External reproductive structures, includes LABIA and GLANS CLITORIS.
Male Reproductive Hormones
1) GnRH
2) FSH
3) LH
4) Inhibin
GnRH (M)
At puberty: hypothalamus releases GnRH (Gonadotropin releasing hormone).
–>Causes pituitary gland to release FSH and LH.
FSH (M)
(Follicle - Stimulating Hormones)
–> Travels to Sertoli cells for Spermatogenesis.
–>Causes Sertoli cells in the seminiferous tubules to release INHIBIN which inhibits further lease of FSH by anterior pituitary.
LH (M)
Travels to interstitial (Leydig) cells, simulate production of testosterone.
–> Causes interstitial/Leydig cells to release testosterone which negatively feeds back to hypo/pit.
Andropause
At age 40: decline in testosterone and spermatogenesis, makes reproduction less likely.
–> Can cause low sperm count, loss of muscle/bone mass, depression, increased risk of prostate cancer.
Female Reproductive Hormones
At birth: females have finite number of immature follicles (primary follicles).
At puberty: one follicle will develop each month, producing one mature egg.
–>Ovaries produce female sex hormones ESTROGEN and PROGESTERONE.
Menstrual Cycle
Starts at puberty and ends at menopause.
–>28 day cycle, ensures uterus is ready to receive a potentially mature egg.
–> Made up of OVARIAN CYCLE and UTERINE CYCLE.
–> Both occur at the same time in different locations.
Oogenesis Steps
Formation and development of egg.
–> Each follicle contains:
1) Primary Oocyte (immature egg)
2) Granulosa Cells (help and nourish developing egg)
Follicle cells start dividing, follicle increases in size.
–>Follicle bulges out, eventually burst, causing egg to be released from ovary (ovulation).
Left Over Follicle Cells –> Corpus Luteum
If no fertilization / pregnancy occurs, corpus luteum degenerates in ~10 days.
Ovarian Cycle Stages
1) Follicular Stage
2) Luteal Stage