Biology Flashcards
Ovaries
Store and release eggs
Fallopian tubes
It carries the egg to the uterus, fertilization occurs here
Uterus
The (womb) is where the fertilized egg becomes implanted and finds nourishment
Cervix
The cervix leads from the vagina to the uterus
Vagina
The vagina holds the male penis during sexual intercourse
Ovulation
An egg is released from the ovary an average of every 28 days
Menstruation/Period
The uterus becomes thicker and richer in blood vessels to be ready to receive the egg. If it’s not fertilized by a sperm the thicken uterus breaks away and a small amount of blood passes out through the vagina
Fertile period
These are the days of the menstrual cycle when the woman is most likely to become pregnant
Intercourse 2 or 3 days before, during or after ovulation could lead to fertilization because sperm cells can survive for this long
Pause to menstrual cycle
If an egg is fertilized, the menstrual cycle is paused for the duration of pregnancy. The first sign of pregnancy is often that menstruation does not happen.
Menopause
Signals the end of a female’s ability to reproduce and also the end of her menstrual cycle. It happens at different ages for different people, typically in the late 40’s to early 50’s.
Testes
Produces Sperm
Scrotum
Is where the testes are, it’s located outside the body to ensure the temperature is lower than body temperature for healthy sperm.
Epididymis
Is a coiled tube on the outside of each testis that stores sperm and allows them to mature fully
Vas deferens
Sperm duct
Seminal vesicles, prostate gland and Cowper’s gland
Produces seminal fluid which mixes with sperm to form semen, it nourishes the sperm and allow them to swim.
Penis
It enters female and ejaculates semen
Puberty
Puberty describes when the body starts becoming sexually mature (reproductive organs develop). It normally happens between the ages of 10 and 16.
Male puberty
In males, sex hormones (testosterone) are released causing the voice to deepen, hair grows around the sex organs, face, chest and underarms, the testes and penis grow bigger and start to produce sperm
Female puberty
In females when the sex hormones (oestrogen and progesterone) are released the breasts develop, hips widen, and hair begins to grow on the body.
Fertilization
If an egg is present in the Fallopian tube, and a couple have sexual intercourse, then one of the sperm cells fuse with it
The nuclei of the sperm and egg fuse together to form a fertilized egg
The woman is now pregnant
Embryo
The fertilized egg then divides a number of times and the tiny group of cells moves down the Fallopian tubes to the uterus
This group of cells settles into the lining of the uterus and continues to divide to form an embryo
Zygote - Embryo - Fetus
Egg and sperm fuse to form a single -Zygote Cell division occurs and growth -Embryo, which attaches to the lining of the uterus (implantation) grows more, and after 8 weeks looks like a human -Fetus
Pregnancy
The average length of a human pregnancy is 40 weeks
As the embryo develops in the uterus it is protected inside a bag of fluid called amniotic fluid
This fluid provides a cushion for the embryo
Umbilical cord
A tube called the umbilical cord joins the embryo to the placenta
Placenta
The placenta is rich in blood vessels
It is here at the placenta that food and oxygen from the mothers blood pass into the baby’s blood
Also wastes such as carbon dioxide pass from the baby’s blood into the mothers
Birth
The birth of a baby begins when the uterus muscles start to contract
The is called labour
The bad of amniotic fluid bursts “waters break” and further contractions push the baby our usually head first, through the vagina
The umbilical cord is cut and the placenta (afterbirth) comes out after
Lactation
The mother may choose to breastfeed the infant
The production of breast milk is called lactation
The first three days of milk is called colostrum-very nutritious, and helps protect the baby from infection
Family planning
Natural methods of contraception aim to detect the day ovulation takes place and avoid inter course during the fertile period
Contraception
Artificial methods of contraception prevent the sperm and egg meeting
An example of this is a condom which prevents sperm entering the vagina
Another example is the contraceptive pill which prevents ovulation
It is important to realize no method is 100% reliable
Inherited characteristics
Many physical characteristics such as eye colour and shape of ears were inherited from your parents. The instructions for these inherited characteristics were carried in the two cells that made you the egg and sperm
Chromosomes and genes
The nucleus of each sex cell (gamete) contains 23 thread like structures called
Chromosomes
Chromosomes are made of protein + DNA
These chromosomes carry genes
Genes
Genes are chemicals found on chromosomes that pass on information from parents to children
DNA
Deoxyribonucleic acid
Taxonomy
It’s the science of classifying organisms
Classification
It’s the placing of organisms into groups, based on similar characteristics.This simplifies the study of organisms and allow scientists to communicate with each other. The basic unit of classification is the species.
Species
It’s a group of organisms that are capable of interbreeding to produce fertile offspring. (Liger = sterile offspring of a male lion and a female tiger) (A mule is the sterile offspring of a male donkey and a female horse)
Natural selection
Natural selection is the process by which the members of a species who are best suited to their environment are most likely to survive and reproduce.
Variation
Variation means the differences in characteristics between members of the same species.
Variation caused by environment
(where and how we live). Our body fat is caused by how much we eat and how much exercise we do, and any hormonal factors affecting our body
Natural selection
Natural selection is the process by which the members of a species who are best suited to their environment are most likely to survive and reproduce.
Peppered
Example of natural selection: peppered moth. Lighter moths survive in less polluted areas, darker ones survive in the cities. The genes for light or dark wings are passed on more often depending, on where they live.
