HUMAN REPRODUCTION

in man

What is reproduction?

The process by which living organisms generate new individuals of the same kind of themselves.

What are the 2 types of reproduction?

Asexual and Sexual

What is sexual reproduction?

Sexual reproduction involves 2 parents. It combines genetic material from both parents to produce genetically diverse offspring. (meiosis)

What is asexual reproduction?

Asexual reproduction is the process by which a single organism (one parent) produces offspring that are genetically identical to itself. (mitosis)

Why is asexual reproduction described as 'conservative’

Asexual reproduction is described as 'conservative' because it produces offspring that are genetically identical to the parent, preserving the parent's genetic traits.

Why is reproduction important?

Reproduction is essential for the survival of species.

List 4 differences between Asexual and Sexual Reproduction

1. Number of parents: Asexual involves one parent, while sexual involves two.

2. Genetic diversity: Asexual produces identical offspring meaning that all offspring have an equal chance of survival as long as the parent does. sexual produces diverse offspring (variation) which enables offspring to be possibly better adapted to an environment

3. Asexual reproduction is a rapid process as there is no need to find a mate. This results on more offspring being produced. Sexual reproduction is a slow process as a mate has to be found, embryo has to develop, feritlization, etc.

4. Organisms produced by asexual reproduction usually stick close to the parent which increases overcrowding and competition. However, offspring produced by sexual reproduction are usually dispersed

True or False: Many plants use both types of reproduction, combining the advantages of both

True

What is a gamete?

A gamete is a reproductive cell that fuses with another during fertilization to form a zygote.

What is the female gamete and where is it produced?

The female gamete, called an ovum (or egg), is produced in the ovaries of female organisms.

How are the fallopian tubes/oviduct adapted to their purpose?

They contain cillia that help move the egg towards the uterus.

Why is the embryo implanted into the uterus lining?

The embryo is implanted into the uterus lining to establish a connection for nutrient and oxygen exchange. It has a rich blood supply

What is the function of the cervix?

The cervix acts as a passageway between the vagina and the uterus, providing protection and support during pregnancy and facilitating childbirth. It keeps the neck closed during pregnancy.

What is the male gamete and where is it formed?

The sperm/spermatozoa is the male gamete. It is produced in the testes.

What is the difference between the location of ova in a female and the sperm in a male?

The ova are produced in ovaries which are located inside the body, In contrast, the sperm is produced and stored in testes (sacs called scrotum) which are located outside the body.

Why are sperm kept outside the body?

Sperm are kept outside the body to maintain a temperature that is cooler than the body's internal temperature, which is necessary for proper sperm production and viability.

What do the seminal vesicles and prostate gland do?

They produce seminal fluid to aid in the transportation of sperm. It mixes with sperm to form semen

What is the ‘sac’ called?

Scrotum

What is the function of the epididymis?

The epididymis stores and matures sperm after they are produced in the testes.

What is the function of the vas deferens?

The vas deferens transports sperm from the epididymis to the ejaculatory duct/ urethra during ejaculation

About how much ova will eventually mature?

about 400 to 500 ova

To produce a mature ovum, what process does the immature ovum undergo?

Meosis - (4 cells produced) Only one develops into a mature ovum and it is released during ovulation

What is ovulation?

The release of a mature ovum from the ovary into the fallopian tube.

What is a primary follicle?

An immature ova inside a fluid filled space.

What is a Graffian Follicle?

A mature follicle that contains a fully developed ovum, ready for ovulation.

What happens to the Graffian follicle after ovulation?

It transforms into the corpus luteum which later degenerates

What are seminiferous tubules

The coiled structures in the testes where sperm production occurs.

Differentiate between an ova and a sperm in terms of:

1. Production

2. Movement

3. Lifespan

1. Production - Ova are produced each month during the period of puberty to menopause

2. Movement - ova move through fallopian tubes by means of muscular contractions and the beating of cilia

3. Lifespan - Ove live up to 24 hrs after ovulation while sperm can live up to 2 to 3 days in the female after ejaculation.

What are the four hormones that manage the menstrual cycle?

• Follicle Stimulating Hormone

• Oestrogen

• Luteinising Hormone

• Progesterone

What is the function of progesterone

Progesterone is a hormone that prepares the uterus lining for potential implantation of a fertilized egg and helps sustain pregnancy if conception occurs.

What secretes the Follicle Stimulating Hormone?

The pituitary gland

What produces oestrogen?

The graafian follicle in the ovaries.

What happens to progesterone levels if fertilisation does not occur?

If fertilization does not occur, progesterone levels decrease, leading to the shedding of the uterine lining and the onset of menstruation.

What is menstruation?

Menstruation is the monthly shedding of the uterine lining when pregnancy does not occur, resulting in vaginal bleeding. (about 14 days after ovulation)

What is implantation in reproduction?

Implantation in reproduction is the process by which a fertilized egg attaches itself to the lining of the uterus, allowing for further development into an embryo.

What is a zygote?

A zygote is a fertilized egg formed from the union of a sperm and an ovum.

Describe the process of fertilization

If an ovum is present in the fallopian tube, a sperm enters the ovum leaving its tail behind. A fertilisation membrane forms around the fertilised ovum to prevent additional sperm from entering. The nuclei of the ovum and sperm fuse to form a zygote

By what process does the zygote divide?

MITOSIS

What is the placenta?

The placenta is a disc of tissue with capillaries running throughout and finger like projections called villi that project into the uterus lining.

The embryo is joined to the placenta by an ______ ____

Umblilical Cord

Give 2 ways that the placenta protects an embryo

It prevents the mixing of the mother’s and the embryo’s blood

It prevents unwanted substances such as bacteria and viruses from the mother’s blood

What is the use of the umblilical artery?

It transports carbon dioxide and other waste away from the embryo

Name the structure that carries dissolved food and oxygen to the embryo

Umbilical vein

What is the amnion?

A thin, tough membrane surrounding the developing embryo and offers protection.

Describe the characteristics of a human embryo/foetus at about 8 weeks

At about 8 weeks, a human embryo/foetus has developed major organs and systems, including limbs, facial features, and a heartbeat.

At 10 weeks during development, the embryo is known as a _____

fetus

At around how many weeks do the kidneys start to function?

About 10 weeks

How long is the gestational period considered to last?

The gestational period is typically considered to last approximately 40 weeks

What hormone stimulates muscles in the uterus wall to start contracting?

Oxytocin

What is the ‘afterbirth’?

The term 'afterbirth' refers to the placenta and other membranes that are expelled from the uterus following the birth of the baby.

As the placenta develops, it takes over secreting __________

Progesterone

What must be considered when choosing a birth control method?

The reliability, side effects, whether both partners are comfortable using it

What 2 birth control methods prevent against STIs

The condom and abstinence

Why is withdrawal acceptable to all religious groups?

It does not involve the use of artificial devices or pills

What is a spermicide?

A spermicide is a cream, jelly, or foam inserted into the vagina before intercourse. It kills sperm

True/False: Spermicides are reliable

False; they are not considered a reliable form of birth control on their own.

Give 3 disadvantages of using a condom

• interferes with enjoyment

• Condoms can tear allowing sperm to enter the vagina

• Latex may cause an allergic reaction

State 2 contraceptive methods that function as barriers

Condoms and Diaphragms

What is an IUD?

A T-shaped plastic device usually containing copper (toxic to gametes) inserted into the uterus by a doctor

Give 2 advantages and 2 disadvantages of using an IUD

Advantages: long-term protection, low-maintenance. Disadvantages: potential discomfort, must be inserted by a doctor

How do contraceptive pills/birth control pills work?

They contain hormones (usually progesterone & oestrogen) that suppress the production of LH and FSh (responsible for ovulation) tricking the body into thinking that ovulation has occurred already

Give 3 reasons why access to birth control is important:

Decreases infant deaths and improves the health and overall care of infants

Prevents unsafe abortions

Decreases health risks to women

Decreases maternal deaths

Enables family sizes to be moderate so that each child is provided for

Enables women to participate fully in society

Reduces population growth to help maintain a healthy, productive environment

List 4 negative effects of the growing human population

Less natural resources

Unemployment

Increase in the spread of infectious diseases

Food shortages

Decrease in living standards

Destruction of the environment

What does AIDS stand for?

Acquired Immunodeficiency Syndrome

What is the causative agent of AIDS

HIV - Human Immunodeficiency Virus

List 3 methods of transmission of AIDS

• Using infected cutting instruments or needles

• Unprotected sex

• Blood transfusions from an infected person

• Infected mother to baby

List 3 methods of treatment for AIDS

1. Antiretroviral Drugs (interrupt the duplication of HIV)

2. Drugs to enhance the immune system

3. Drugs to treat opportunistic infections

Give 4 methods of prevention and control for AIDS

1. Treat all cases especially pregnant women

2. Use sterile needles for all injections

3. Use condoms during sex

4. Test all human products to be given intravenously for HIV

5. Abstain from sexual intercourse

6. Set up education programmes

7. Stick to one uninfected partner

What does Neisseria Gonorrhoeae cause?

Gonorrhoea

What part of a baby does gonorrhea in the mother affect?

It can affect the baby's eyes, leading to conjunctivitis, and may also cause complications during delivery.

List 3 reasons why the control of the spread of HIV/AIDS is difficult

Tht time interval between contracting the virus and showing symptoms may be several years

HAAT (Highly Active Antiretroviral Therapy) is expensive and must be taken for a lifetime

It can be difficult to persuade people to change their sexual behaviour

There is currently NO VACCINE or CURE for HIV/AIDS

Discuss some of the social implications of the continual spread of AIDS and other sexually transmitted infections.

• Discrimination

• Neglect by relatives and friends

• Parentless children

• Decreased standards of living

• Increased Expenditure for Medical Care

• Job Loss

• Shortened Life Expectancies