Biology Flashcards
Ovary
Ovaries store and release eggs
Fallopian tubes
The Fallopian tubes carry the egg to the uterus,fertilisation occurs here
Uterus
The uterus (womb) is where the fertilised 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 28days
Menstruation
At the same time the uterus becomes thicker and rich in blood vessels to be ready to receive the egg another word for menstruation is period
The 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 fertilisation because sperm cells can survive for this long
Pause to menstrual Cycle
If an egg is fertilised, 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 females ability to reproduce and also the end of her menstrual cycle. It happens at different ages for different people, typically in the late 40s to early 50s
Testes
The testes produce sperm
The Scrotum
The scrotum is where the testes are, it is located outside the body to ensure the temperature is lower than the body temperature for healthy sperm
The epididymis
The epididymis is a coiled tube on the outside of each testis that stores sperm and allows them to mature fully.
The vas deferens
The vas deferens (sperm duct) brings the sperm from the testes to the penis
The seminal vesicles, prostate gland and Cowper’s gland
The seminal vesicles,prostate gland and Cowper’s gland produce seminal fluid which mixes with sperm to form semen, it nourishes the sperm and allow them to swim.
Penis
The Penis enters the 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
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
.The first egg is released from the ovaries which leads to the first period occurring
.An egg will be released every mouth until the menopause
Fertilisation
If an egg is present in the Fallopian tube, and a couple have sexual intercourse, then one of the sperm cells may fuse with it.The nuclei of the sperm and the egg fuse together to form a fertilised egg.The woman is now pregnant
Embryo
The fertilised 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 embroyo
Zygote >Embryo >Foetus
Egg and sperm fuse to form a single >Zygote
Cell division occurs and growth
>Embroyo, which attaches to the lining of the uterus (implantation) grows more, and after 8 weeks looks like a human
>Foetus
Pregnancy
The average length of a human pregnancy is 40weeks
As the embroyo develops in the uterus it is protected inside a bag of fluid called amniotic fluid
The fluid provides a cushion for the embroy
Umbilical cord
A tube called umbilical cord joins the embryo to the placenta
The 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 Burt of a baby begins when the uterus muscles start to connect this is called labour
The bag of amniotic fluid bursts water break and further contractions push the baby out 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
To control the number of children you have you need to control the number of times fertilisation takes place
Natural methods of contraception
Aim to detect the day ovulation takes place and avoid intercourse during the fertile period
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 realise no method is 100% reliable
Genes
Genes are chemicals found on chromosomes that pass on information from parents to children
DNA
Deoxyribonucleic acid
Taxonomy
Is the science of classifying organisms
Classification
Is the planning 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.
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Variation
The differences in characteristics between members of the same species. Variations can be acquired ( picked up during the life of organism) e.g riding a bicycle or inherited ( genetic - can be passed on to the next generation ) e.g tongue rolling
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 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
Variation caused by inheritance
The colour of eyes of hair caused by the genes passed from our parents
Nature versus nurture
These two factors interact with each other. How tall a person grows may be influenced by their diet as well as their diet as well as their genes
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 .
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, on where they live.
Evolution
Natural selection explains how evolution happens. Evolution is the gradual change in the inherited characteristics of a species over time. Evolution can lead to new species
Gamete formation
Independent assortment of homologous chromosomes during meiosis ensures genetic variation among gametes
Overbreeding
More offspring are produced (e.g. a tree produces many seeds ) than the environment can support
