Human Reproduction (chpt. 41) Flashcards
Function of : sperm duct
Transport sperm
Function of : urethra
Dual function - carries urine or sperm out of the body
Function of : penis
Releases sperm into the vagina
Function of : epididymis
Where sperm mature and are stored
Function of : testis
Male gonads - produce sperm and testosterone
Function of : scrotum
Holds testes outside the body to provide a cooler temperature
Why are the testes held outside the body
To allow a cooler temperature for meiosis to take place - 37°C too hot
Male reproductive system - glands
Seminal vesicle
Prostate gland
Cowper's gland
Function of : glands in male reproductive system
Produce seminal fluid which provides nourishment for the sperm
Secondary sexual characteristics
Features that distinguish males from females
Gonad
An organ that produces sex cells
What makes up semen
Sperm and seminal fluid
Testosterone
Produced in testes
Primary and secondary sexual characteristics
Luteinising hormone (LH) males
Produced in pituitary gland
Causes production of testosterone
Follicle stimulating hormone (FSH) males
Produced in pituitary gland
Stimulates sperm producing cells to divide by meiosis to produce sperm
Secondary sexual characteristics in males
Deeper voice
Growth spurt
Body hair
Muscular development
Infertility
The inability to produce offspring
Male infertility
Low sperm count
Caused by drug abuse OR lack of hormones
Treatments: lifestyle change OR drug therapy, IVF
What section of the sperm enters into the egg
Only the head
Function of : Fallopian tube
Transport the egg to the uterus using cilia and peristalsis
Function of : ovary
Female gonad - produces eggs, oestrogen, progesterone
Function of : endometrium
Where zygote implants - placenta formation
Function of : cervix
Opening of womb
Function of : vagina
Birth canal
Function of : uterus
Protects the developing foetus
Menstrual cycle
A series of events that occur every 28 days on average in the female if fertilisation has not taken place
Menopause
When ovulation and menstruation stop happening in a female
Menstruation
Is the discharge of the endometrium and the unfertilised egg
Menstrual cycle days 1-5
MENSTRUATION (PERIOD)
Endometrium is shed
FSH stimulates the Graafian follicle to develop and secrete oestrogen
Menstrual cycle days 6-13
REPAIR
Oestrogen from the GF inhibits FSH and travels to the uterus where it stimulates the rebuilding of the endometrium and the production of LH in pituitary gland
Graafian follicle matures
Menstrual cycle day 14
OVULATION
Mature Graafian follicle moves to the surface of the ovary and bursts to release the egg into the Fallopian tube
LH causes ovulation and stimulates the formation of the corpus luteum which secretes progesterone and oestrogen
Menstrual cycle days 15-21
REST / SECRETORY PHASE
Empty GF develops into corpus luteum which secretes progesterone and oestrogen
Walls of uterus prepare for implantation
Menstrual cycle days 21-28
Egg passes into the uterus and if unfertilised, begins to degenerate
Progesterone and oestrogen levels drop and the walls of the endometrium break down
FSH is produced
Cycle repeats
Role of menstrual cycle
Prepare for pregnancy
Egg development
Ovulation
Menstrual disorders
Fibroids - benign growths in uterus
Cause is uncertain
Treatments: radiation or surgically removed
Female infertility
Blockage of Fallopian tubes due to scarring
Caused by an infection e.g. STD
Treatment: surgical opening of tubes or IVF
Copulation
The act of sexual intercourse
What happens during copulation
Sexual arousal causes the penis to become stiff and erect due to increased blood flow
The clitoris becomes erect and the vagina becomes lubricated
Orgasm
The physical and emotional sensations experienced at the peak of sexual excitement
Ejaculation
The release of semen from the penis
Insemination
The release of semen into the vagina just outside the cervix
How many sperm are released during copulation
500 million sperm are released into the female
Many die on the journey or due to acidic vagina secretions
Fertilisation
When the nucleus of the sperm fuses with the nucleus of the egg, forming a diploid zygite
Where does fertilisation occur
Fallopian tube
How long do eggs survive
Up to 2 days
How long do sperm survive in the female
Up to 7 days
Implantation
The embedding of the fertilised egg into the uterus
What is the placenta made of
Formed partly from the cells of the embryo and partly from the cells of the endometrium
Function of placenta
- Prevents blood from mixing (different blood types and mothers higher blood pressure)
- Transfers gases and nutrients
- Endocrine gland - it secretes progesterone and oestrogen
Development of zygote
DAY 1 - FERTILISATION
Contains 46 chromosomes
All mitochondrial DNA from egg
DAY 3 - MORULA
Divides rapidly by mitosis
Solid clump of cells is formed
DAY 5 - BLASTOCYST
Hollow ball of a few hundred cells
Pushed from Fallopian tube to uterus
What does IVF stand for
In Vitro Fertilisation
What is IVF
It involves removing an egg from the ovary and fertilising it outside of the body
Germ layers
Basic layers of cells in the blastocyst from which all adult tissues and organs will form
3 germ layers and what they form
ECTODERM - skin, hair, nails, nervous system
MESODERM - bone, muscles, circulatory, reproductive system
ENDODERM - liver, pancreas, thyroid, digestive, respiratory system
Development of embryo
Germ layers
Up to 8 weeks, the limbs form, heartbeat, sex organs, cartilage becomes bone (ossification)
Ossification
Cartilage becomes bone when the embryo is developing
FSH Females
Pituitary gland but works in ovary
Stimulates oestrogen and development of graafian follicle
Oestrogen
Produced by Graafian follicle in ovary
Repairs endometrium
Secondary sexual characteristics
Stimulates LH
Secondary sexual characteristics in females
Pubic and underarm hair
Breasts
Growth spurt
LH Females
Pituitary gland
Ovulation and development of corpus luteum
Stimulates progesterone
Progesterone
Produced by corpus luteum
Maintains endometrium
Stops uterus from contracting
Birth - stage 1
DILATION
Secretion of progesterone decreases allowing uterus to contract
Pituitary produces oxytocin which increases contractions
Become stronger and more frequent
Mucus plug and amniotic fluid released
Birth - stage 2
EXPULSION
Contractions become stronger and the baby descends head first into birth canal
Umbilical cord is clamped and cut
Birth - stage 3
AFTERBIRTH
Placenta and foetal membranes are birthed
How does the egg prevent more than one sperm from entering
It forms a membrane
Why do sperm need digestive enzymes
To break down the membrane surrounding the egg
What type of immunity is passed from mother to baby by breastfeeding
Passive / acquired
Where exactly in the ovary are eggs produced
Oocyte or follicle
Lactation
The secretion of milk by the mammary glands (breasts) of the female
Benefits of breastfeeding for the baby
- perfect food at correct temperature
- sterile at room temperature
- contains antibodies
- bonding of mother and baby
Benefits of breastfeeding for mother
- delays return of menstrual cycle
- reduced risk of breast cancer
- uterus contracts quicker due to oxytocin
- bonding of mother and baby
Birth control
Methods taken to limit the number of children that are born
Contraception
The deliberate prevention of fertilisation or pregnancy
Natural contraception
Track cycle & work out fertile period
Chemical contraception
The pill - tablet containing oestrogen and progesterone, prevents ovulation
Barrier / mechanical contraception
Condom - prevents sperm entering vagina
Surgical contraception
Tubal ligation - oviducts cut & tied
Vasectomy - sperm ducts cut & tied
DIAGRAM of female reproductive system
DIAGRAM of male reproductive system
What hormone is responsible for the secretion of breast milk?
Prolactin
What does the placenta form from?
Cells of embryo
Cells of endometrium
