Human Reproduction

Here you have some extra information to learn more about human reproduction. I hope you find it useful to study what we have learnt in class!

Here you have a video which explains the different organs in the male and female reproductive systems:

Here you have a simple diagram of the menstrual cycle: 

Watch this video to learn more about the menstrual cycle:

Human reproduction takes place in 3 different stages: Fertilisation (=conception), Pregnancy and Birth. 

1. Fertilisation

2. During pregnancy the embryo continues its development becoming a fetus which undergoes a lot of changes until birth:

3. Birth

Watch this video to learn more about these three stages:

Watch this video to learn more about 
how a baby develops during pregnancy:

Identical twins and non-identical or fraternal twins

 

Identical twins

Non-Identical twins

Non-Identical twins

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JUST FOR THOSE WHO ALWAYS WANT TO LEARN MORE... HAVE FUN! 

Why do we look like our parents? An introduction to Genetics and DNA

Why do you look like your parents?

What is DNA?

How Gregor Mendel's pea plants helped us understand genetics: 

Gregor Mendel

What is genetics? 
Genetics is the study of genes and heredity. It studies how living organisms, including people, inherit traits from their parents. Genetics is generally considered part of the science of biology. Scientists who study genetics are called geneticists. 

Gregor Mendel is considered the father of the science of genetics. Mendel was a scientist during the 1800s who studied inheritance by experimenting with pea plants in his garden. Through his experiments he was able to show patterns of inheritance and prove that traits were inherited from the parents. 

What are genes? 

Genes are the basic units of heredity. They consist of DNA and are part of a larger structure called the chromosome. Genes carry information that determine what characteristics are inherited from an organism's parents. They determine traits such as the color of your hair, how tall you are, and the color of your eyes. 

What are chromosomes? 
Chromosomes are tiny structures inside cells made from DNA and protein. The information inside chromosomes acts like a recipe that tells cells how to function. Humans have 23 pairs of chromosomes for a total of 46 chromosomes in each cell. Other plants and animals have different numbers of chromosomes. For example, a garden pea has 14 chromosomes and an elephant has 56. 

What is DNA? 

The actual instructions inside the chromosome is stored in a long molecule called DNA. DNA stands for deoxyribonucleic acid. 

Interesting Facts about Genetics

• Two humans typically share around 99.9% of the same genetic material. It's only the 0.1% of the material that makes them different.
• Humans share about 90% of genetic material with mice and 98% with chimpanzees.
• DNA molecules have a specific shape called  "double helix": the DNA molecule is shaped like a twisted ladder. James Watson and Francis Crick solved the structure of DNA. Other scientists, like Rosalind Franklin and Maurice Wilkins, also contributed to this discovery.
• Nearly every cell in the human body contains a complete copy of the human genome in its nucleus. For example, mature red blood cells do not contain nuclear DNA.
• In humans, each cell normally contains 46 chromosomes arranged in pairs. We get 23 chromosomes from our mother and 23 from our father.  Twenty-two of these pairs look the same both in males and females and they are called autosomes. The 23rd pair differ between males and females and they are called sex chromosomes. 
• Some diseases are inherited through genes.
• Some inherited traits are determined by multiple different genes.
• Doctors may be able to cure diseases in the future by replacing bad DNA with good DNA using a process called gene therapy.

(adapted from: 

https://www.ducksters.com/science/biology/genetics.php)

Circulation: Circulatory System

Don't forget that NUTRITION is a complex process that consists of four processes that take place at the same time and involve different sets of specialised organs or systems:

- Digestion

- Breathing

- Circulation

- Excretion

In this post, we are learning more about CIRCULATION

This process allows us to transport nutrients and oxygen to our body cells and waste substances and carbon dioxide from our cells that our bodies must eliminate.

In the circulatory system we find the HEART, which is the main organ of this system, and the BLOOD VESSELS, which are tubes that connect your heart to the rest of your body.










Your heart is a muscle that pumps BLOOD around your body carrying nutrients and oxygen and collecting waste substances and carbon dioxide that our cells must eliminate. It has four chambers: the upper chambers are  the atria and the lower chambers are the ventricles.
Here you have a diagram that also shows the main arteries and veins attached to your heart:

Look at this video to learn more about your heart 

and how it works:

There are three types of BLOOD VESSELS:
- Arteries: wide tubes that carry blood from the heart.
- Veins: narrow tubes that carry blood to the heart
- Capillaries: very narrow tubes that connect arteries to veins and reach every part in our body.




Here you have two diagrams with the main blood vessels in your body (You don't have to learn all these names! It's for your information only):

The BLOOD is made up of a liquid called plasma and three types of cells with different functions:

1. Red blood cells: absorb oxygen in the lungs and transport it to all the cells in our body.
2. White blood cells: fight germs and infections.
3. Platelets: stop bleeding and form scabs.
















HOW DOES BLOOD CIRCULATE?
In fact, the circulation of blood takes place in two steps:
1. Pulmonary circulation is the movement of blood from the heart to the lungs. In the lungs the blood releases carbon dioxide and picks up oxygen in the alveoli; then the blood flows back to the heart. This oxygenated blood has a bright red colour.

2. Systemic or general circulation is the movement of  oxygenated blood from the heart to the rest of the body. The oxygen goes into the cells of our body and the blood picks up carbon dioxide. Then the blood flows back to the heart. This deoxygenated blood has a dark red colour.

Here you have two videos to learn more about the circulatory system: