Sexual Reproduction in Humans

• Male Reproductive System

  A) bladder

  B) glands

  C) sperm duct

  D) urethra

  E) penis

  F) testis

  G) foreskin

  H) scrotum

  
• Male reproductive structures and features

  • The testes keeps the temperature low to avoid having the sperm die from their enzymes denaturing

  A) fluid

  B) semen

  C) nutrients

  D) sperm passes through

  E) mixed

  F) fluids produced by the glands

  G) urethra

  H) ejaculation

  I) tube

  J) centre

  K) urine or semen

  L) ring of muscle

  M) urine and semen from mixing

  N) bag of skin (scrotum)

  O) sperm (male gamete)

  P) testosterone (hormone)

  Q) sac

  R) testes

  S) temperature slightly lower

  T) body temperature

  U) urine

  V) bladder

  W) semen

  X) vagina

  Y) sexual intercourse

  
• • Female reproductive system

  A) oviduct

  B) ovary

  C) uterus

  D) cervix

  E) bladder

  F) urethra

  G) vagina

  
• • Female reproductive system functions
  • Ovaries releases an egg 1x a month

  A) ovary to the uterus

  B) ciliated cells

  C) push

  D) ovum down

  E) fertilisation occurs

  F) ova (female gamete)

  G) mature

  H) develop

  I) hormones are relesaed

  J) muscular bag

  K) soft lining

  L) fertilised

  M) egg (zygote

  N) implanted

  O) foetus

  P) ring of muscle

  Q) uterus

  R) developing foetus in place

  S) pregnancy

  T) muscular tube

  U) inside

  V) male's penis

  W) sperm

  
• Fertilisation - fusion of the nuclei from a male gamete (sperm cell) and a female gamete (egg cell)

  • occurs in the oviducts
• Gametes have adaptations to increase the chances of fertilisation and successful development of an embryo

  A) flagellum (tail)

  B) enzymes

  C) head

  D) acrosome

  E) cytoplasm

  F) energy

  G) jelly coating

  H) changes

  
• Acrosome - contains enzymes that digests the outside of the egg so that the sperm can burrow inside it
• • Gametes structure

  A) acrosome

  B) haploid nucleus

  C) midpiece containing mitochondria

  D) tail aka flagellum

  E) sperm

  F) mitochondrion

  G) cell membrane

  H) cytoplasm

  I) haploid nucleus

  J) jelly coating

  K) egg

  
• • Adaptation of gametes

  A) flagellum (tail)

  B) swim to the egg

  C) enzymes

  D) head region

  E) acrosome

  F) digest

  G) jelly coat

  H) cell membrane

  I) mitochondria

  J) energy from respiration

  K) flagellum

  L) back

  M) forth

  N) locomotion

  O) cytoplasm

  P) store of energy

  Q) energy

  R) dividing

  S) zygote

  T) jelly coating

  U) changes

  V) barrier

  W) fertilisation

  X) prevent

  Y) sperm nuclei

  
• • Male and female gametes comparision
  • sperm is small as it only needs to provide chromosomes while eggs are bigger because they need to have everything for the embryo to grow and develop

  A) small

  B) large

  C) head region

  D) flagellum

  E) round

  F) many

  G) ew

  H) jelly coating

  I) capable

  J) not capable

  K) every day

  L) huge numbers

  M) thousands

  N) immature eggs

  O) ovary

  P) one

  Q) month

  
• Egg cell and sperm cell both have nucleus’s with a haploid number of chromosomes
• Fertility issues:

  • eggs aren’t released
  • blocked oviducts
  • problems with growth in the uterus
  • not enough sperm
  • not enough nutrients to prostate
  • blocked sperm duct
• Pregnancy Process (1) :

  • after fertilisation in the oviduct, the zygote travels towards the uterus
  • takes about 3 days (difficult for the mom to know they are pregnant) - the zygote will divide several times to form a ball of cells known as an embryo
  • in the uterus, the embryo embeds itself in the thick lining (implantation) and continues to grow and develop
  • gestation period - for humans it is 9 months
• Pregnancy Process (2):

  • development of organs takes place within the first 12 weeks - the embryo gets nutrients from the mother by diffusion through the uterus lining
  • the organs are all in place and the placenta has formed - the embryo is now called a fetus
  • remaining gestation time is used by the foetus to grow bigger in size
• Pregnancy diagram

  A) placenta

  B) uterus

  C) umbilical cord

  D) fetus

  E) aminiotic fluid

  F) cervix

  G) vagina

  
• Fetus is surrounded by an amniotic sac

  • aminiotic sac - contains amniotic fluid (made from the mother’s blood plasma)
  • protects the fetus during development by cushioning it from bumps to the mother’s abdomen
  • protects it from temperature fluctuations
• Umbilical cord - joins the fetus’s blood supply to the placenta for exchange of nutrients and removal of waste products
• The fetus develops and grows during the gestation period by gaining the glucose, amino acids, fats, water and oxygen it needs from the mother’s blood

  • bloods run opposite each other, never mixing, in the placenta
  • the fetus’s blood connects to and from the placenta by the umbilical cord
• The mother’s blood absorbs waste from the fetus’s blood in the placenta

  • e.g. substances like carbon dioxide and urea are removed from the fetus’s blood so that they do not build up to dangerous levels
• Movement of all molecules across the placenta occurs by diffusion due to difference in concentration gradients (learn at least two specific substances that move in either direction across the placenta)

  • placenta is adapted for this diffusion by having a large surface area and a thin wall for efficient diffusion
• The placenta acts as a barrier to prevent toxins and pathogens getting into the fetus’s blood

  • not all toxin molecules or pathogenic organisms such as viruses are stopped from passing through the placenta - this usually depends on the size of the molecule
  • pregnant women are advised not to smoke during pregnancy as molecules like nicotine can pass across the placenta
• After the baby has been born, the umbilical cord is cut – this does not hurt as there are no nerves in it, just two blood vessels

  • tied off to prevent bleeding - shrivels up and falls off after a few days leaving the belly button behind
• Afterbirth - placenta detaches from the uterus wall shortly after birth and is pushed out due to contractions in the muscular wall of the uterus
• Placenta Diagram

  A) placenta

  B) umbilical cord

  C) fetus' blood vessels

  D) villi

  E) placental membrane

  F) placenta

  G) mother's blood vessels

  H) intervillous space

  
• The placenta and uterus are stuck together allowing things to cross over to or from the mother’s blood via the placenta
• The placenta adds hormones during the pregancny
• Placenta - attaches to the umbilical cord to the wall of the uterus and oxygen and carbon dioxide is exchanged by diffusion
• Substances exchanged across placenta

  • urea
  • alcohol
  • pathogens
  • amino acids
  • glucose
  • carbon dioxide
  • oxygen
• Smoking - reduces oxygen supply for the foetus causing less respiration, resulting in a smaller baby
• Rubella virus - risk of miscarriage and still birth
• The mother’s blood and foetus’s blood doesn’t mix but substances are actually diffused across
• Define a haploid nucleus

  A nucleus that only contains one set of chromosomes
• What are the substances transferred across the placenta?

  urea

  alcohol

  pathogens

  amino acids

  glucose

  carbon dioxide

  oxygen
• What is the function of the umbilical cord?

  Carries the fetal blood to and from the placenta
• What does the cervix do during labour and birth?

  Dilates
• What are the type of chromosomes in a sperm cell?

  X and Y
• What are the secondary sexual characteristics girls possess?

  Growth of sex organs, pubic hair, breasts grow, start of menstruation
• What part of the body only transports urine in the male body?

  Ureter
• How does the scrotum help in terms of temperature?

  It keeps the testes in a temperature lower than body temperature as high temperatures affect the enzymes in the sperm
• How does the mitochondria in the sperm help?


  It gives the sperm energy via aerobic respiration so that it can swim towards the egg cell