Grade 9 Science

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​The Respiratory system is a biological system consisting of specific organs and structures used for gas exchange in plants and animals.It is the network of organs and tissues that help you breathe.

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​This system consist of -nasal cavity ,sinuses,pharynx, larynx, trachea, bronchi, bronchioles,alveoli,lungs, and diaphragm.

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THE BREATHING PROCESS:

Breathing or respiration is composed of two processes:

1. Inspiration( inhalation) - taking in air makes the intercostal muscle push the ribs upward,sternum rise,diaohragm contract and increase the lungs' volume.

2. Expiration(exhalation) - expels carbon dioxide from the lungs into the atmosphere and reduces the volume of the lungs​

​PARTS OF RESPIRATORY SYSTEM

1. Diaphragm -​ is a thin dome -shaped muscular part of the respiratory system that separates thoracic cavity and abdominal cavity.

2. Nose and nasal cavity - the nose ,where the nasal cavity is located.Nasal cavity is the passageway of air that we breathe in.Just inside the nosesmall hairs callled cillia are located,this part of the nose traps the dirt and other particles from the air we take in​.

3. Pharynx - or the throat is a tubelike part that serves as the common passageway of the air we breathe and the food we eat.

4. Larynx - is located in the chamber below pharynx.It consist of the epiglottis, voice box and the vocal cords

5. Trachea - or windpipe includes walls made of C - shaped catilage ring that are open to all the time.The function of trachea is to get rid of mucous that contain too much dust by coughing and expectoration​

​6. Bronchi and Bronchioles - the bronchi are the two tubes connected to the lungs.They are located in the lower part of the trachea connected to the lungsThe Bronchioles are the smaller tubes of the left and the right bronchi that branch into the lungs.

7. Lungs- are the part of the respiratory system that fill the thoracic cavity.The main function of the lungs is for respiration.It transport oxygen from the atmosphere into the bloodstream and release waste material ( carbon dioxide) from the body into the atmosphere.

8.Alveoli - In the last part ​of the terminal bronchioles are tiny bubble like brunch of structures called alveoli or airsacs.

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​Circulatory System - is a system of organs that includes the heart,blood and blood vessels,used to circulation the blood throughout the entire body of a human or other vertebrate.It is the life support structure that nourishes your cells with nutrients from the food you eat and oxygen from the air you breathe.The circulatory system function with other body system to deliver different materials in the body.It circulates vital elements such as oxygen and nutrients.At the same time it also transport wastes away from the body.

​The three major parts of Circulatory System

1.Heart - pumps blood throughout the body. ​

2. Blood vessel - carries the blood throughout the body

a. arteries - carry oxygenated blood away from the heart to the cells, tissues, and organs of the body

b. veins - carry deoxygenated to the heart

c. capillaries - the smallest blood vessels in the body, connecting the smallest arteries to the smallest veins.The actual site where gases and nutrients are exchanged.

3, Blood - carries the materials throughout the body​

​TYPES OF CIRCULATION

1. Pulmonary Circulation - movement of blood from the heart to the lungs and back to the heart.

2. Coronary Circulation - movement of blood through the tissues of the heart

3. Systemic Circulation - movement of blood from the heart to the rest of the body, excluding the lungs ​