RESPIRATION

RESPIRATION 

Breathing—you do it all the time, actually you’re doing it right now. But you hardly ever think about it, unless you suddenly can’t breathe; then, it becomes very clear that you have to breathe in order to live. 

But why is breathing important? 

Your body needs oxygen in order to get energy from the foods you eat. Breathing makes this process possible. 

The respiratory system is responsible for taking in oxygen and releasing carbon dioxide. 

RESPIRATION AND THE RESPIRATORY SYSTEM

The words breathing and respiration are often used to mean the same thing. However, breathing is only one part of respiration. 

RESPIRATION is the process by which a body gains and uses oxygen and gets rid of carbon dioxide and water. 
 and it is divided in two parts:

•First one is breathing, involving inhaling and exhaling.

•Second part is cellular respiration, involving chemical reactions that release energy from food.

Breathing is made possible by your respiratory system. 

The respiratory system is the group of organs that take in oxygen and get rid of carbon dioxide. 

The nose, throat, lungs, and passageways that lead to the lungs make up the respiratory system. 

Next Figure shows some parts of the Respiratory System. 

Breathing

When you breathe, air is sucked into or pushed out of your lungs. However, your lungs have no muscles of their own. Instead, breathing is done by the diaphragm 

The diaphragm is a dome-shaped muscle beneath the lungs. When the diaphragm contracts and moves down, you inhale. The chest cavity’s volume gets larger. At the same time, some of your rib muscles contract and lift your rib cage. As a result, your chest cavity gets bigger and a vacuum is created. Air is sucked in. Exhaling is this process in reverse. 

•Air travels to the lungs through the nose or mouth, then the pharynx, larynx, trachea and bronchi. In the lungs, the bronchi branches into many many bronchioles, which branch into millions of alveoli.

The alveoli are bunches of tiny air sacks inside the lungs.

When you breathe in, they fill with air.

Breathing and Cellular Respiration
In cellular respiration, oxygen is used by cells to release energy stored in molecules of the sugar glucose. Where does the oxygen come from? 

When you inhale, you take in oxygen gas. This gas moves into red blood cells and is carried to tissue cells. The oxygen then moves out of the red blood cells and into each cell. Cells use the oxygen to release energy. During this process, carbon dioxide (CO2) and water are made. Car- bon dioxide is exhaled from the lungs.

Chemical reaction of cellular respiration process that happens in the alveoli is as follows:

Vocabulary 3rd Term: RESPIRATION

1.     Respiration: in biology, the exchange of oxygen and carbon dioxide between living cells and their environment; includes breathing and cellular respiration

2.     Respiratory System
: a collection of organs whose primary function is to take in oxygen and expel carbon dioxide

3.     Pharynx: the passage from the mouth to the larynx and esophagus

4.     Larynx: the area of the throat that contains the vocal cords and produces vocal sounds

5.     Trachea:  the tube that connects the larynx to the lungs

6.     Bronchus: one of the two tubes that connect the lungs with the trachea

7.     Alveolus:  any of the tiny air sacs of the lungs where oxygen and carbon dioxide are exchanged

8.     Photosynthesis: the process by which plants, algae, and some bacteria use sunlight, car- bon dioxide, and water to make food

9.     Chlorophyll:  a green pigment that captures light energy for photosynthesis

10.  Cellular respiration: the process by which cells use oxygen to produce energy from food

11.  Stoma:  one of many openings in a leaf or a stem of a plant that enable gas exchange to occur (plural, stomata)

12.  Transpiration: the process by which plants release water vapor into the air through stomata

13.  Emphysema: destruction of the alveoli for gas exchange which causes extreme shortage of breath

14.  Asthma: a condition in which your airways narow and swell, producing extra mocus, making breathing difficult.

15.  Bronchitis: inflammation of the mucous membrane in the bronchial tubes. It typically causes bronchospasm and coughing.

16.   Flu (INFUENZA): a highly contagious viral infection of the respiratory passages causing fever, severe aching, and catarrh, and often occurring in epidemics.

17.  Common cold: is a viral infection of the upper respiratory system, including the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes.

 18.   Lung cancer is the uncontrolled growth of abnormal cells that start off in one or both lungs; usually in the cells that line the air passages. The abnormal cells do not develop into healthy lung tissue, they divide rapidly and form tumors.

Nutrition

This section will introduce you to the structure and function of the digestive system. 
We  will compare mechanical and chemical digestion and we trace the food´s path through the disgestive tract. At the end of this term you will understand the importance of having a balance diet in order to stay healthy.

Why do we eat?
Human beings eat to growth, to get energy and to stay healthy.

Do you know why do you feel hungry? You feel hungry because your brain receives signals that your cells need energy. 

But, eating is the begining of the story. Your body changes the food into substances your cells can use for growth, tissue repair, metabolism, movement, etcetera. 

Your digestive system is a group of organs that work together to digest food so that it can be used by your body. 

DIGESTIVE SYSTEM

The most obvious part of the digestive system is a series of tubelike organs called the digestive tract, which includes your mouth, pharynx, oesophagus (gullet), stomach, small intestine, large intestine, rectum and anus.

Did you know that the digestive tract may be as long as 9 m!

The digestive system is composed of two sets of organs: those that made up the digestive tract and those that are called accesory organs. 
Accesory organs include the salivary glands, the gailbladder, the liver and the pancreas. 


Lets explore some of the functions of each of the digestive system´s organs.

digestive system´s organs´functions
http://www.musclesculpt.com/digestive.swf


DIGESTION is the process of breaking down food, such as your cheese sandwich into a form that can pass from the digestive tract unto the bloodstream

There are two types of dygestion: mechanical and chemical. The breaking, crushing and mashing of food is called mechanical digestion.
In chemical digestion, large molecules are broken down into nutrients. 
Nutrients are substances present in food (aliments) that the body needs for normal growth, maintenance and repair. So minerals, vitamins and roughage are nutrients present in a carrot (aliment) 

There are 7 major types of nutrients:
proteins: made of small units called amino acids
carbohydrates: sugars such as glucose
vitamins: 
minerals
fats: made of fatty acids and glycerol
fibre (roughage)
water

Substances called enzymes break some nutrients into smaller particles that the body can use: glucose, amino acids, fatty acids, glycerol, etc.  

For example proteins are chains of smaller molecules called amino acids. Proteins are too large to be absorbed into the bloodstream. So enzymes cut up the chain of amino acids. Amino acids are small enough to pass into the bloodstream. 

Enzymes act as chemical scissors to cut the long chains of amino acids into small chains.  

Examples of three different enzymes:
Pepsine is an enzime that acts on proteins to broken them down into amino acids.

Amilase is an enzyme that acts on starch to broken it down into sugars.

Lipase is an enzyme that acts on fats to broken it down into fatty acids and glycerol.

NUTRITION AND NUTRITIONAL DISORDERS ...

VISIT MY SITE AT GOOGLE

Norma´s Site at Google

https://sites.google.com/a/sagradocorazonmexico.edu.mx/biology-s-class/

2ND TERM VOCUABLARY

ALSO GO AND VISIT MY SITE AT GOOGLE

2nd Term Vocabulary at Norma Google´s Site


https://sites.google.com/a/sagradocorazonmexico.edu.mx/biology-s-class/vocabulary-2nd-term/vocabulary-2nd-term

CELLS: THE BASIC UNITS OF LIFE

This section will introduce you to cells, their discovery and their diversity. You will also learn the parts of the cell and their functions.  

Why weren´t cells discovered until 1665?
What invention made their discovery possible?

Cells weren´t discoverd until 1665 because almost all cells are too small to be seen with the naked eye. The microscope is the invention that made their discovery possible. 

Robert Hook was the first person to describe cells. In 1665 he built up a microscope to look tiny objects and one day he looked at a thin slice of coork, which looked like if it was made of little boxes. As they reminded him of the small rooms monks lived in at monastey
He named this boxes: cells. In 1673 Anton van Leeuwenhoek, made his own microscopes and used to look at pond scum. He saw small organisms moving all around in the water and named animalcules. Today we called them protists.

200 years later, around 1839 two scientists : Matthias Schleiden and Teodor Schwann concluded that cells are present in all living things. Soon after they wrote what is nowadays called: 

The Cell Theory:

1. All organisms are made of one or more cells.

2. The cell is the basic unit of all living things.

3. All cells come from existing cells. 

Remember the first subject we reviwed together. I told you
Living things are made of cells and that these cells were the basic building blocks of life. 

But how small really are they? how much a micrsocpe is enhancing their size? Remember I told you to think of a sandcastle. If you see it from the distance it will look like a smooth building. But as you get closer you begin to see is made of millions of tiny sand grains.  

Let´s see how small cells really are: 

Interactive scale to cells

Click start and look at the size of different things you know. Wonder about the tiny size of cells, including protists such as amoeba and parmecium or the bacteria E.coli or even look at the size of the carbon.

Light microscopes magnify 1500 times an object. Nowadays we have electron micorscopes which may magnify 500,000 times the actuak size if an object.

bacterial cell size  is around 1 micrometer (see below an E. coli under the electron microscope)

•1 micrometer=  0.001 mm

We now eucaryotic cells are generaly from one to two hundred times bigger than prokaryotic cells: see below an electron micrography of an amoeba.

With microscopes scientists observed that all cells contain certain small specialized structures: a memebrane, cytoplasm and Genetic material (DNA), and ribosomes. Althouugh, only some of them were having their DNA cover in a membrane, we nowadays called nucleus. So cells were divided in two different types:

Procaryotes: cells without nucleus, unicellular organisms.

Eukaryotes: cells with nucleus, this cells may belong to unicellular or multicellular organisms.

Also scientists observed that eukaryotic cells shown some other specialized structures, we called them organelles and each one, has specific functions.

Organelles: 

Nucleus: The nucleus controls the cell activity.

It contains the cell´s DNA or genetic material

Ribosomes: organelle composed of RNA and proteinsThe site where proteins are made

Endoplasmic Reticulum: composed of a

system of membranes.  

Helps the production and processing of proteins.

Mitochondria. Main power source of cell

The site of cellular respiration.

Lysosomes. Similar to kidneys

The organelle that digest food particles, wastes, cell 

parts for recycling and foreign invaders

Golgy´s apparatus. Where proteins are 

transported

Where proteins are processed and transported out the

cell

Vacuole: is a vesicule
They are useful to storage materials

Chloroplasts: Where photosynthesis take place
The organelle that uses the energy of sunlight to make food. Chloroplast are green because they contain chlorophyll

Now, click on the link below to see the different organelles in two kinds of eykaryotic cells: animal and plant cells.

Types of cells

Scrool your mouse down the cells alive page to found out about the specific function of each organelle in each cell type. Compare them! What is similar and what is different between plant and animal cells? Let´s watch the videos below and found out.

Now watch this video on cell structure to understand the different functions of each oragnelle. 

cell structure

Comparition bwteween Animal and Plant Cells

Then there are two main types or categories of cells: prokaryotic cells and eukaryotic cells. Both of these types of cells have several things in common. All cells are surrounded by a plasma membrane, whithin this membrane, is the cytoplasm which is composed of the fluid and organelles of the cell.

Bacteria (Kingdom Monera) are prokaryotes. They do have DNA, but it is not organized into a true nucleus with a nuclear envelope around it. Also, they lack many other internal organelles such as mitochondria and chloroplasts. 

Organisms in the other four kingdoms are eukaryotes. Their DNA is organized into a true nucleus surrounded by a nuclear envelope. The nucleus of eukaryotic cells contains the genetic material which chemically directs all of the cell’s activities. 

Plant Cell Diagram

Different Cell types: 

cell specialitiation (cell/tissues / organs / Organ Systems)

• Once you had learned that the cell is the smallest unit of life
•  let´s focus on multicellular organisms.
• 
  
• Organisms are like machines, some have just one part like bacterias and others have many parts, like us: we have got trillions of cells

Being multicellular have some benefit:

• Lager size
• Long life: life span is not limited to a single cell
• Specialization: each type of cell has a particular job. 

Lets´watch this video to see how it works

Cells, tissues, organs and organ systems

So cells work together. 

A tissue is a group of cells that work together to perform a specific job. For example Cardiac muscle tissue is just one type of tissue in a heart. 

Animals have four basic types of tissues: nerve tissue, muscle tissue, connective tissue and protective tissue.

Plants have three types of tissues: transport tissue, protective tissue and ground tissue (where photosynthesis takes place)

Then tissues work together

an organ is formed when two or more tissues work together to perform a specific function

And Finally a group of organs working together to perform a particular function is called an organ system. For example your digestive system.