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Chapter 16 Human Sexual Reproduction System - Coggle Diagram
Chapter 16 Human Sexual Reproduction System
16.1 Function of the Human Sexual Reproductive System
Sexual Reproduction
Many organisms reproduce
sexually
This means their young are formed when the
nuclei of two sex cells join together
. The sex cells in humans are an
egg
cell and a
sperm
cell
These two cells are produced by different parts of the male and female reproductive systems
The fusion of sex cells is called
fertilisation
. When an egg cell is fertilised, it develops into an embryo and develops into a new individual. This new individual contains the
genetic material (DNA)
from both its parents
Heredity
The
passing down of genetic material
from one generation to the next during sexual reproduction is called heredity
Family Resemblance & Variations
Children
inherit traits or characteristics
from parents
Children are not identical to their parents and possess a mix of traits from both their parents
During sexual reproduction, the individual
receives genetic material from the mother via the egg, and from the father via a sperm
Inheriting any traits is a random process
. An offspring can inherit any possible combination of traits from its parents. This explains why an individual is different from their parents and even their siblings
The genetic trait that are passed down
can be desirable, undesirable or neutral
to the next generation. Therefore, certain disorders or diseases such as sickle cell anaemia, or cystic fibrosis can be passed down from parent to offspring.
16.2 How each Parts of Each Reproductive System Works Together
Puberty
Period when an adolescent becomes capable of reproducing and experiences rapid growth and development
Sex and growth hormones cause changes to other body systems such as the skeletal and muscular systems
Similarities between Boys and Girls
Height and Weight increases
Armpit hair growth
Pubic hair growth
Difference between Boy and Girls
Boys
Facial hair growth
Voice-box enlarges and voice deepens
Muscle strength increase
Penis and testes increase in size
Production of sperm and ejaculation occurs
Girls
Breast begin to develop and uterus enlarges
Hips become broader and rounder
Maturation of eggs and menstruation begins
Male Reproductive System
Scrotums (Singular: scromtum)
Holds the testes outside body
Testes (Singular: testis)
Produce sperm & male hormones
Urethra
Tube that passes through the centre of the penis, from the bladder to outside body
During sexual intercourse, sperms pass from the testes into sperm ducts to urethra to the external environment
Carries urine and semen
Penis
Contains numerous blood capillaries which fills with blood during sexual intercourse to allow the penis to become erect
Sperms are ejaculated through the penis during intercourse
Sperm duct
Muscular tube that carries sperms from testis to urethra
Female Reproductive System
Egg
Contains nucleus which contains hereditary information to be pass down from one generation to the next
Structure and Functions of the Female Reproductive System
Ovaries (Singular: ovary)
Produces eggs and female sex hormones
One of the ovaries produces an egg every month
Fallopian tube/Oviduct
Narrow muscular tube connecting the ovary to the uterus
Walls of oviduct contract to push egg towards uterus
Uterus
Pear shaped organ with thick muscular walls
Inner surface is covered by uterine lining
Cervix
Circular ring of muscle at the lower end of the uterus
Vagina
Muscular tube which joins cervix to the outside of the body
Site of sperm deposition during intercourse
Menstruation
Menstruation is the monthly discharge of blood, uterine lining and unfertilised egg from the uterus via vagina
Typically 28 days cycle
Process and Descriptions
Menstruation
If a sperm does not fertilise an egg, uterine lining breaks down and menstruation begins
Discharge of blood, uterine lining and unfertilised egg through the vagina
Remarks : Beginning of menstrual cycle
Repair of uterine lining
Uterine Lining is repaired
Further thickening of uterine lining
Uterine lining grows thicker & becomes rich with blood capillaries
Ovulation
Release of egg from one ovary into fallopian tube
Remarks : 14 days
before next
menstruation
(e.g., day 14 in a 28-day cycle)
Fertile period
If sexual intercourse takes place within this period, it is likely to result in pregnancy
Remarks : 4 days before and 1 day after ovulation
(e.g., day 10 to 15 in a 28-day cycle)
Maintenance of thickness of the uterine lining
Uterine lining remains thick to supply embryo with nutrients and oxygen for growth
Fertilisation and Pregnancy
During sexual intercourse, sperms are deposited in the vagina and move up the uterus to oviduct to the egg
If an egg is present, fertilisation may occur
Fertilisation
is the
fusion
of the
nucleus
of the sperm and
nucleus
of an egg(ovum) to form the zygote
Fertilised eggs then divides repeatedly to form an embryo
Embryo moves into the uterus and implants in the uterine lining. The woman is now pregnant
Embryo develops into a foetus
At the end of the 9 months of pregnancy, muscles of uterus contract to push the foetus out; cervix enlarges to allow the foetus to pass through during birth
16.3 How the Functions of the Human Reproductive System can be Disrupted
Substance abuse
Smoking, consumption of alchohol and abuse of controlled drugs are harmful. During pregnancy, it can also harms the foetus
Effects of Substance Abuse
babies may be born premature
babies may be born with low birth weight
smoking may affect the development of the foetus' heart, lungs and brain
alchohol consumption and abuse of drugs can lead to physical, intellectual and behavioural challenges in the child
Birth control
: refers to the methods and devices used to prevent pregnancies
Temporary Methods
that prevents
fertilisation
Rhythm Method (Calendar method)
Sexual intercourse occurs during the non-fertile period of the menstrual cycle. (avoid fertile period of menstrual cycle).
Condom
The condom collects sperms so that the sperms are not released into a woman's vagina
Diapghram
The diaphragm blocks access to the cervix so that sperms cannot pass from the vagina into the uterus
Spermicide
Chemicals used to kill sperms
Permanent Methods
that prevents
fertilisation
Surgical Method
Also known as steralisation
Most reliable form of contraception
Usually irreversable
Male sterilisation : Vasectomy
Sperm ducts are cut and tied, preventing sperms from reaching penis
Sexual characteristics are not affected: Testes continue to secrete male hormones
Female sterilisation : Tubal ligation
Both oviducts are cut and tied, preventing the sperms from reaching the oviduct to fertilise the egg
Temporary Methods
that prevents
ovulation
Contraceptive Pills / Birth Control Pills
Contains hormones that prevent release of egg from ovary
Temporary Methods
the prevents
implantation
Intra-uterine device (IUD)
Coil which is inserted into the uterus to prevent the implantation of the embryo into uterine wall
Abortion
(Not a form of birth control)
Abortion is the deliberate termination of a pregnancy
Foetus is removed using medication or surgical means
Complications that might arise from abortion
Damage the uterus
resulting in bleeding
/
resulting in infertility
(inability to conceive)
Developing an infection after the procedure
16.4 How Medical Advancements Impact Human Reproduction and Survival
Sexually Transmitted Infections (STI)
Gonorrhea : Caused by bacteria
Signs & Symptoms :
Can be infertile
Babies can become blind if bacteria enters eye during birth
Mode of Transmission :
Sexual intercourse (exchange of body fluids of reproductive system)
Contaminated blood
Childbirth
Breast-feeding
Treatment methods :
Can be cured by antibiotics
Presentation methods : - Avoid having multiple sexual partners
Avoid sharing instruments that can break the skin and be contaminated with blood, like razors, toothbrushes
Ensure that needles used for ear-piercing, acupuncture are properly sterilised or insist on disposables
Donated blood should be screened for HIV before use
Syphilis : Caused by bacteria
Signs & Symptoms :
May become blind
Inability to move parts of the body
Can lead to heart failure, insanity and death if left untreated
Mode of Transmission :
Sexual intercourse (exchange of body fluids of reproductive system)
Contaminated blood
Childbirth
Breast-feeding
Treatment methods :
Can be cured by antibiotics
Prevention methods :
Avoid having multiple sexual partners
Avoid sharing instruments that can break the skin and be contaminated with blood, like razors, toothbrushes
Ensure that needles used for ear-piercing, acupuncture are properly sterilised or insist on disposables
Donated blood should be screened for HIV before use
Acquired Immunodeficiency Syndrome (AIDS) : Caused by Human Immunodeficiency Virus which attacks immune system
Signs & Symptoms :
During late stage of HIV infection, person suffers from weight loss, lung infections and brain infections
Mode of Transmission :
Sexual intercourse (exchange of body fluids of reproductive system)
Contaminated blood
Childbirth
Breast-feeding
Treatment methods :
No cure, drugs only present to alleviate symptoms and control progress of infections
Prevention methods :
Avoid having multiple sexual partners
Avoid sharing instruments that can break the skin and be contaminated with blood, like razors, toothbrushes
Ensure that needles used for ear-piercing, acupuncture are properly sterilised or insist on disposables
Donated blood should be screened for HIV before use
Growth in World Population
Thw world population grew greatly in the twentieth century due to the following factors :
Medical Advancements
Increased Food Production
Improved Transportation
Improved Sanitation
Medical Advancement
:
New drugs, vaccines and medical treatments helped people to survive and live longer lives
New diagnostics techniques allowed faster and more accurate diagnosis for patients
Inventions like pacemakers, defibrillators and lung machines helped patients that would have died otherwise
Increased Food Production
: Overall food supply increased, which allowed less people to die from hunger.
These factors increased overall food supply :
Advances in technology allowed plants to be grown in poor soil
Farm animals had more food and were kept healthier with new drugs
More efficient breeding methods allowed more abundant and cheaper farm food
Improved Transportation
: Improvement in technology allowed goods such as food and medicine to be supplied to more regions in a shorter time
Improved Sanitations
: Better sanitation and waste management reduced the spread of deadly diseases such as cholera and typhoid through human waste containing the bacteria