Reproduction In Humans Flashcards
Sexual Reproduction
Reproduction that occurs with use of gametes
Puberty
Period during which sexual maturity occurs
Gametogenesis
Process where gametes are produced from germinal epithelium of male & female gonads
Spermatogenesis
Process where spermatozoa are produced from germinal epithelial of testes
Oogenesis
Process where ova are produced from germinal epithelium of ovary
Menstrual cycle
Changes that occur in ovary & uterus of a female over a period of 28 days
Ovulation
Process where ovum is released from Grafiaan follicle of ovary
Uterine cycle
Changes that occur in walls of uterus as it thickens until menstruation occurs
Oestregen
Hormone secreted by Grafiaan follicle & is responsible for thickening of endometrium
Endometrium
Lining of uterus
Menstruation
Discharge of blood & other material from lining of uterus at intervals of about one month
Gestation period
(pregnancy)
Period where Embryo develops in uterus until baby is born
Foetus
Name given to Embryo when it reaches 12 weeks
Chorion
Outermost membrane around foetus
Amnion
Membrane found inside chorion
How does Puberty in males & females begin
When GnRH stimulates the anterior pituary gland to secrete :
FSH
LH
Secondary sexual characteristics
Follicle Stimulating Hormone in males
Stimulates testes to produce sperm
Luteinising Hormone in males
Stimulates testes to produce testosterone
Secondary sexual characteristics caused by testosterone
Development of muscles & broad shoulders, public hair, beard, deep voice, larger testes & penis
Development & functioning of prostate gland, seminal vesicles & cowpers gland
FSH in females
Stimulates a follicle in ovary to develop & secrete oestregen
LH in females
Stimulates development of corpus luteum in ovary to secret progesterone
Secondary characteristics in females
Growth of public hair, breasts
Onset of menstruation
What is the male reproductive system made of
Tubes
Glands
Organs
Scrotum.
Sac that holds testes
Testes
Male reproductive organ that produce sperm cells
Epididymis
Tube where spermatozoa mature
Prostate gland
Where ejaculatory duct passes through & meets urethra & produces & releases highly alkaline mucus secretion
Vas deferens
Sperm duct that stores sperm for a few hours to 42 days
And carries sperm from epididymis to ejaculatory ducts
Seminal vesicles
Secretes a slightly alkaline mucus which serves as food source for sperm as it contains fructose
Cowpers gland
Secretes an alkaline secretion that cleanses urethra & lubricates penis
Urethra
Tube that carries ejaculate out of body
Penis
External organ made up of spongy tissue that delivers sperm into females body
Testes
Male gonads that lie outside abdominal cavity
Seminiferous tubules
Small tubules lined by germinal epithelium responsible for production of spermatozoa
Cells of Sertoli
Specialized cells rich in glycogen found in seminiferous tubules
Glycogen purpose in Cells of Sertoli
Form of glucose to provide nutrients for energy for sperm to swim
Interstitial /leydig cells
Found between seminiferous tubules to secrete testosterone
Function of epididymis
Stores sperm for 2-3 months
Ejaculatory duct
Carries sperm & secretions of glands /semen
Urethra
Tube that transports sement and urine
Accessory organs & purpose
Cowpers gland
Seminal vesicles
Prostate glands
Pour their secretions into vas deferens & ejaculatory ducts
Function of semen
Promotes movement of sperm by helping them swim vigorously
Provides sperm with nutrients to keep them alive
Function of sperm tail
Swim towards ovum
Function of nucleas in sperm
Carries genetic info. from males to fuse with ovum nucleas to produce offspring
Function of mitochondria
Releases energy for tail to move
Function of acrosome
Releases energy to penetrate ovum
Sterilization
An operation which prevents conception permanently
Vasectomy
Sterilization of a man
Why testes are found outside abdominal cavity
Maintain temperature of testes at 35 degrees Celsius to ensure production of sperm cells can occur
Ovary
Female gonads responsible for production of ova, oestregen & progesterone
Germinal epithelium in females
Lines ovary & produces follicles that secrete oestrogen & progesterone
Fallopian tubes & significance
Tubes that transport the ovum from the ovary to uterus
Pathway for sperms to reach ovum
Fertilisation occurs
Has cilia & muscular to love ovum to uterus
Uterus functions
Embryo attaches /becomes implanted to uterus lining
Embryo develops inside it
Muscles for contraction during birth
Cervix functions
Allow menstrual blood to flow into the vagina
Direct the path of sperm into uterus for fertilisation
Becomes blocked by mucus when pregnant to avoid infections
Vagina function
Penis is inserted to deposit sperm
Passageway for menstrual blood
Serves as birth canal
What does the anterior pituary gland in males release
FSH
LH
Where is Gonodotropin releasing hormone released
Hypothalamus to stimulate pituary gland
Interstitial /Leydig cells in males role
Releases testosterone which stimulates spermatogenesis associated with sex drive & ssc
Sertoli cells significance
Releases inhibin which feeds developing sperm cells
Also slows FSH & LH if required
Menstrual Cycle cycles
Ovarian cycle (leading to production of ova in ovary)
Uterine cycle (prepares lining of uterus to receive fertilised egg in uterus)
Follicular phase
- FSH released
- Primary follicle develops for about 10 days into graafian follicle
- Follicle produces oestregen
- Oestregen thickens endometrium
Days of Menstrual cycle changes
1-4: menstruation
4- 14: follicular phase
14: ovulation
15-28: luteal phase
Luteal phase
Day 15-16: corpus luteum formed, progesterone peak & oestregen
Endometrium increase to receive fertilised egg cell
Day 23-28: Unfertised ovum results in shrinking corpus luteum, progesterone stop
What happens during day 23-28 when ovum has been fertilized
Corpus luteum remains active
Progesterone still secreted
Follicles no longer develop in ovaries
Menstrual Cycle stops & menstruation doesn’t begin
Copulation
Sperms deposited into vagina through sexual intercourse
How is it possible for only one sperm to penetrate ovum
A fertilisation membrane forms around ovum acting as a barrier soon after sperm enters
Steps to fertilisation
Copulation
Sperm penetrates ovum
Ovum releases fertilisation membrane
Neck & tail of sperm break of
Sperm nucleas enters Ovums nucleas
How does the egg travel when released from ovary
- Egg released
- Egg picked up by funnel of oviduct
- Eggmoved along oviduct by cilia
- Sperm fertilizes egg
How is the uterine wall structurally developed for its function
Thick
Vascular
Glandular
For implantation
Role of oestrogen and progesterone in implantation
Oestregen ensures endometrium is thickened
Progesterone ensures pregnancy is maintained by ensuring Embryo remains attached to uterine wall
Formation of embryo
- Sperm & Ovum
- Fertilisation forms zygote
- 2 cell stage
- 4 cell stage
- Morula
- Blastula
- Gastrula
- Blastocyst
- Embryo
Implantation
Embryo attaches to wall of uterus
Development of embryo within time frame
14 days after fertilization: Small about 1mm
2. 4 weeks old: cor shaped 5 mm, formation begins
3. 12 weeks: resembles human 75 mm foetus
Placenta
Life support machine of developing Embryo providing :
Oxygen & food
Removing toxic materials & CO2
How placenta is structurally developed for function
Many villi:
Stick into blood spaces of uterus wall
Mothers blood circulates through these.
Role of placenta
Attaches foetus to mother
Allows for diffusion of dissolved food & oxygen to foetus
Allows for diffusion of nitrogenous waste & CO2 from foetus to mother
Secretes own progesterone after 12 weeks
Umbilical cord significance
Attaches placenta to Embryoand has vessels:
Umbilical artery (urea & CO2 from foetus)
Umbilical vein (glucose, H2O, slats, amino acids, vitamins, fatty acids & glycerol)
How does blood of mother not make direct contact with foetus
Blood separated by walls of chronic villi which extended into maternal sinuses(blood filled spaces).
Amniotic fluid funtion
Shock absorber for mechanical injury
Maintains temp range
Allows free movement
Umbilical cord vessels
1 artery: carries blood with less oxygen and nitrogenous waste from foetus to placenta
- Vein carries blood in oxygen & food to foetus
