Human Reproduction Flashcards
Reasons living things reproduce
- Form new individuals
- Allow continuation of species
- Prevent extinction
Extinct
When all individuals of a species have died out completely
Offspring
The young produced by an organism
Gametes
The sex cells (sperm cells and egg cells)
Fertilisation
The fusion of a sperm and egg
Embryo
The early development period of an individual
The baby before it becomes a foetus
Genetic information
The inherited information passed from parents to offspring in the form of DNA
Asexual reproduction
- Only one parent
- Offspring genetically identical to parent
- No gametes involved
Sexual reproduction
- Two parents
- Gametes produced
- Offspring similar to both parents but not identical
Three main parts of the sperm
- Head - contains nucleus with DNA
- Middle piece - contains mitochondria for energy
- Tail - used for swimming
Main parts of a human egg cell
- Nucleus containing DNA
- Cytoplasm with food store
- Protective ‘jelly’ coating
DNA
- A molecule that contains coded information
- Determines an organisms inherited characteristics
The head of the sperm
- contains the nucleus
- contains DNA from the father
The middle piece of a sperm cell
- Contains mitochondria
- Provides energy for swimming
The tail of a sperm cell
- A whip-like flagellum structure
- Used for swimming
Layer surrounding a human egg cell
- A protective layer
- Jelly like
- Prevents multiple sperm from fertilising the egg
Contained in a human egg cell
- Nucleus with mothers DNA
- Cytoplasm with a food store
Advantage of asexual reproduction
- Faster than the process of sexual reproduction
- Exactly the same characteristics in offspring as parent
- Only one parent required
Benefits of sexual reproduction
- Promotes variation in a population
- Every combination of different gametes results in a unique individual
Puberty
- A stage in the human life cycle when the sexual organs mature
- Occurs usually between 10-15 years in humans
The structure that starts the process of puberty by releasing hormones
The pituitary gland
Hormones
- Chemicals that are made by glands that speed up or slow down the activities of an organ
- They are, in essence, chemical messengers
The effect of hormones released by the pituitary that initiates puberty
- Makes the reproductive organs active
- Reproductive organs begin to make sex hormones
Primary reproductive organ and hormone in males
- The testes
- testosterone
Primary reproductive organ and hormone in females
- Ovaries
- Oestrogen
The effect of testosterone in males (secondary sexual characteristics)
- Facial hair
- Vocal cords make voice deeper
- Broader shoulders
- Muscular body
- Hair growth over body, under arms and pubic hair
- Penis and testes develop
- Testes start to make sperm
The effect of oestrogen in females (secondary sexual characteristics)
- Hair under arms and pubic hair
- Breasts grow larger
- Hips become wider
- Ovulation and menstruation begins
Example emotional changes often experienced through puberty
- Strong emotions or feelings
- unexplained mood changes
- Changes in self-esteem
- Agression
- Depression
The main purpose of sexual reproduction in organisms
- For gametes to join
- For the continuation of species
Main parts of the male reprocuctive system
- Testes
- sperm duct
- Male glands
- Urethra
- Penis
Main purposes of male reproductive system
- To make and store sperm
- To place sperm in the female
Function of testes
- To make sperm
- Produce testosterone
Tube carrying sperm from testes to the penis
The sperm duct / vas deferens
The tube carrying sperm through the penis
The urethra
The function of the male glands
- Secrete added to sperm to make semen
- This fluid helps sperm to survive and swim to the eg
Function of the prostrate gland
- Secretes a fluid to nourish and protect sperm
- helps to form semen
Function of the urethra in males
- To carry uring out the body
- To carry semen out the body
- Never at the same time
Funcrion of the scrotum
- A sack of skin to hold the testes outside the body
- Sperm production is better at a slightly lower temperature than the core body temperature
Semen
A mixture of sperm and fluids from the male glands, including the prostrate gland
Ejaculation
The rapid release of semen from the penis
Penis
- The structure for placing semen inside the female during copulation
- The penis becomes erect when extra blood is pumped into it
Foreskin
- A fold of skin that covers the head of the penis
Circumcision
- Surgical removal of the foreskin
- Is often done for religious or cultural reasons
- If sone under unsterile conditions, infection may occur
The main funccion of the female reproductive organs
- To make eggg cells
- To provide suitable conditions for the early growth of a baby
Vagina
- A muscular tube opening to the outside of the body
- Receives the penis during sex
- Allows the birth of a baby (the birth canal)
Cervix
- The opening from the vagina into the uterus
- Also called the ‘neck of the womb’
The uterus
- A hollow, muscular wall
- Where a baby grows while a woman is pregnant
- Also called the ‘womb’
Oviducts
- The tubes that carry the egg down from the ovary to the uterus.
- Lined with tiny hairs that push the egg along.
- The sperm also swim to meet the egg and fertilisation takes place here.
Ovaries
- Make the eggs
- Release one egg each month
- Also make femaile sex hormones e.g. oestrogen
Main parts of the female reproductive system
- Ovaries
- Oviducts
- Uterus
- Cervix
- Vagina
Ovulation
- The release of a ripe egg from the ovary
- Occurs once a month
Most likely time to fall pregnant
- While a woman is ovulating
- A number of days before and after ovulation
Menstruation
- When the wall of the uterus passes out of the body through the vagina
- If the egg is not fertilised
The menstrual cycle
- The cycle of changes occuring to the wall of the uterus
- in preparation for receiving a fertilised egg.
When the menstrual cycle is said to begin (Day 1)
- The first day of menstruation
- When a womans ‘period’ starts
The typical timing of ovulation during the menstrual cycle
Day 14
Copulation
- Also called intercourse or sex
- The penis becomes erect as it fills with blood
- The vagina becomes moist
- The penis is placed inside the vagina
- Ejaculation takes place
Contraception
- Birth control
- A method or device used to prevent pregnancy.
Methods of contraception
- fertility awareness e.g. abstinence
- long-acting reversible contraception, such as the implant or intra uterine device (IUD)
- hormonal contraception, such the pill or the injection.
- barrier methods, such as condoms.
