Human Reproduction Flashcards
What is in the male reproductive system?
The testes formed inside the body but moved outside during birth. Their function is to make spermicide, store spermicide and produce the hormone testosterone.
The Scrotum maintains the testes at a temperature of 35 degrees. At this temp meiosis can take place to form viable sperm. Meiosis will not take place at body temperature(37)
The epydidimis stores and matures sperm cells
The sperm ducts transport sperm from the testes to the urethra
The Seminal vesicles, prostate gland and cowper’s gland produce Seminal fluid. This causes the sperm to start swimming and provides food for them to swim for 2 days
The urethra runs throughout the middle of the penis and it carries sperm or urine
Sperm are produced in the testes within a series of tubes. They are produced by Meiosis and as a result they are haploid with 23 chromosomes
“A gamete is a haploid cell capable of fertillisation”
What are the male hormones?
FSH is made in the pituitary gland from the onset of sexual maturity until lunch end of life, puberty takes place aged 12 or 13. Function is to stimulate meiosis as a result causes sperm to be produced
LH is produced in the pituitary gland. From puberty till end of life. It stimulates production of testosterone
Testosterone is produced in the testes. From puberty till end of life. Initially triggers formation of primary male traits. At puberty it causes secondary male traits
What is male infertility?
“Infertility is the inability to produce offspring”
Cause: low sperm count may be due to smoking of cigarettes, alcohol abuse, use of Marijuana or anabolic steroids or lack of FSH
Treatment: Depending on cause treatment may involve stopping smoking cigarettes, alcohol Marijuana or steroids
Sometimes FSH is injected
If all these fail in vitro fertilisation may be tried
What is in the female reproductive system?
The ovaries: contain a large number off potential eggs. From puberty( age 11) until menopause(45-55)
Normally produce eggs each month
Also produce oestrogen and progesterone
Each egg produced as a result of meiosis
Egg develops in fluid filled sac called graffian follicle
Changes in the ovary: graffian forms oestrogen during first half of menstrual cycle
When mature it moves to surface of ovary
At ovulation (middle cycle) it bursts to release an egg
When it enlarges it moves back into ovary and fills with yellow cells. This yellow structure is called
Corpus luteum
The Corpus luteum produces progesterone during second half of menstrual cycle
The fallopian tube: funnel collects egg when released from ovary
Contains cilia which move egg along the tube towards uterus
Egg may be fertilised in fallopian tube
Uterus: site where embryo and foetus are nourished . Wall made of involuntary muscle.
Lining of uterus endometrium, helps nourish embryo
The cervix: opening where sperm may enter through and out which baby is born
The vagina: where sperm is placed during intercourse:
What is the menstrual cycle?
A series of events that occur every 28 days
The menstrual cycle takes place only between puberty and menopause
It ceases to occur if the female is pregnant
Involves four main hormones in sequence:
1. FSH 2. Oestrogen 3. LH 4. Progesterone
Each of these hormones can be said to :
Cause the production of the next hormone
Inhibit the production of the previous hormone
What is the role of hormones in the menstrual cycle?
FSH is made in the pituitary gland, from puberty to menopause + day 1 of each menstrual cycle, stimulates meiosis and cause production of egg and formation of graaffian follicle
Oestrogen is made in graffian follicle of ovary, between days 5 and 14( very little days 1 -4 as graaffian is small), causes endometrium to develop, inhibits FSH (why it’s in contraceptive pill), high level of oestrogen stimulate streak production of LH
LH is produced in the pituitary gland, day 14 of menstrual cycles, causes ovulation, causes graaffian follicle to convert into Corpus luteum, inhibits production of oestrogen, stimulates production of testosterone
Progesterone is produced in the Corpus luteum in ovary,from days 14 to 28, it maintains the growth of the endometrium, inhibits LH and prevents the uterus from contracting, inhibits FSH ( part of contraceptive pill)
What happens on day 28 of the menstrual cycle?
The Corpus luteum stops producing progesterone
This results in the following events….
- The uterus can now contract. These contractions cause the endometrium to breakdown, and the blood and tissue are expelled from the body in a process known as menstruation( period)
- menstruation marks day 1 of the next cycle and lasts for about 5 days
FSH can now be made. It cause a new egg to form on day 1 of the next cycle
What is a menstrual disorder?
Fibroids - symptoms
Fibroids are benign tuners of the uterus. Range from the size of a pea to a grape fruit
They are most common if females aged 35 to 45
Small Fibroids produce no symptoms. Large ones cause severe menstrual bleeding, anemia, pain, miscarriage or infertility
- cause
The cause of Fibroids is uncertain but seem to be linked with high levels of oestrogen ie. Common in those who take the contraceptive pill
-Prevention
Avoidance of oral contraceptives
- Treatment
Small Fibroids do not require treatment apart from regular observation. Larger Fibroids are removed by surgery
What is female infertility?
Endocrine gland failure
-problem
The failure of the female to produce FSH means she does not produce eggs
Failure to produce LH means she may make eggs but does not ovulate
-Treatment
Most common treatment involves injecting the appropriate hormone at the correct time in the menstrual cycle
If this fails in vitro fertilisation may be tried
What is copulation?
“Copulation means coupling, the act of sexual union or intercourse”
Stages include…..
- sexual arousal in males cause blood flow from penis to become blocked. As a result penis becomes erect
- In females arousal causes vagina to enlarge and lubricated.
- In both genders there’s and increase in blood pressure and breathing
During copulation the penis moves inside the vagina
Copulation may result in many pleasurable experiences called orgasm. In males orgasm results in seven being expelled from penis, called ejaculation
What is pregnancy?
Sperm are released into female reproductive system which is called insemination.Takes place in vagina close to cervix
Sperm swims twords a chemical released from the egg( this is called chemotaxis)
Sperm swim through the cervix along the endometrium and into fallopian tube
Enzymes from the head (acrosome) of sperm break down the membrane of egg
The head of the sperm enters egg
A new membrane forms around the egg . This prevents anymore sperm entering
What is fertilisation?
“Fertillisation is the union of the nuclei of the sperm and egg to form a diploid zygote”
Fertillisation occurs in the fallopian tube. Takes place on days 14 or 15
Fertile time:
Eggs can survive for 2 days. Sperm can survive for up to 7 days in female system.
Egg is released on day 14. Fertillisation can occur if sperm enter the female between days 7 and 16. Days 12 to 16 the fertile time in menstrual cycle
Describe the development of the embryo
Zygote divides rapidly by mitosis. After 3 days it forms solid ball of cells called a morula
Around day 5 hollow ball of cells called blastocyst forms
Outer cells of the blastocyst(trophoblast) will later form membranes around embryo
The inner cells form the embryo
The morula is pushed down the fallopian tube by the movement of cilia
“Implantation is the burrowing Goffs the blastocyst into the lining of the uterus”
Implantation takes lace on day 7(after fertillisation). At this stage pregnancy is said to have started
Trophoblast forms finger like projections (villi) which grow into the endometrium. These villi absorb oxygen and food from blood
