● The respiratory system includes the nasal cavity, pharynx, larynx, trachea, bronchi,
lungs, and diaphragm.
● The nasal cavity and its associated structures filter, warm, and humidify the air as it
enters the body.
● The pharynx is a shared passage for air and food, and it is divided into three parts: the
nasopharynx, oropharynx, and laryngopharynx.
● The larynx, also known as the voice box, contains the vocal cords and plays a crucial
role in speech production.
● The trachea, or windpipe, is a flexible tube that connects the larynx to the bronchi and
allows air to pass in and out of the lungs.
● The bronchi are the main branches of the trachea that lead to the right and left lungs.
They further divide into smaller bronchioles, which eventually terminate in small air sacs
called alveoli.
● The alveoli are the site of gas exchange, where oxygen from the inhaled air diffuses into
the bloodstream, and carbon dioxide, a waste product of metabolism, diffuses out of the
bloodstream into the alveoli to be exhaled.
● The diaphragm is a dome-shaped muscle located at the base of the thoracic cavity that
plays a key role in breathing. It contracts and flattens during inhalation, allowing the
lungs to expand and air to enter, and relaxes during exhalation, allowing the lungs to
recoil and air to be expelled.
F. Digestive System
● The digestive system is responsible for processing food and extracting nutrients for the
body's energy needs.
● It is composed of the mouth, pharynx, esophagus, stomach, small intestine, large
intestine, rectum, and anus, as well as associated organs such as the liver, gallbladder,
and pancreas.
● The mouth is the site of ingestion and mechanical digestion of food, where it is broken
down into smaller pieces by chewing and mixed with saliva to form a bolus that can be
swallowed.
● The esophagus is a muscular tube that connects the mouth to the stomach and propels
food downward by peristaltic contractions.
● The stomach is a muscular organ that mixes food with gastric secretions to form chyme,
which is then gradually released into the small intestine for further digestion and
absorption.
● The small intestine is the site of most nutrient absorption, and it is divided into three
parts: the duodenum, jejunum, and ileum.
● The large intestine, also known as the colon, absorbs water, electrolytes, and some
vitamins, and forms feces for elimination.
● The rectum stores feces until they are eliminated through the anus.
G. Urinary System
lungs, and diaphragm.
● The nasal cavity and its associated structures filter, warm, and humidify the air as it
enters the body.
● The pharynx is a shared passage for air and food, and it is divided into three parts: the
nasopharynx, oropharynx, and laryngopharynx.
● The larynx, also known as the voice box, contains the vocal cords and plays a crucial
role in speech production.
● The trachea, or windpipe, is a flexible tube that connects the larynx to the bronchi and
allows air to pass in and out of the lungs.
● The bronchi are the main branches of the trachea that lead to the right and left lungs.
They further divide into smaller bronchioles, which eventually terminate in small air sacs
called alveoli.
● The alveoli are the site of gas exchange, where oxygen from the inhaled air diffuses into
the bloodstream, and carbon dioxide, a waste product of metabolism, diffuses out of the
bloodstream into the alveoli to be exhaled.
● The diaphragm is a dome-shaped muscle located at the base of the thoracic cavity that
plays a key role in breathing. It contracts and flattens during inhalation, allowing the
lungs to expand and air to enter, and relaxes during exhalation, allowing the lungs to
recoil and air to be expelled.
F. Digestive System
● The digestive system is responsible for processing food and extracting nutrients for the
body's energy needs.
● It is composed of the mouth, pharynx, esophagus, stomach, small intestine, large
intestine, rectum, and anus, as well as associated organs such as the liver, gallbladder,
and pancreas.
● The mouth is the site of ingestion and mechanical digestion of food, where it is broken
down into smaller pieces by chewing and mixed with saliva to form a bolus that can be
swallowed.
● The esophagus is a muscular tube that connects the mouth to the stomach and propels
food downward by peristaltic contractions.
● The stomach is a muscular organ that mixes food with gastric secretions to form chyme,
which is then gradually released into the small intestine for further digestion and
absorption.
● The small intestine is the site of most nutrient absorption, and it is divided into three
parts: the duodenum, jejunum, and ileum.
● The large intestine, also known as the colon, absorbs water, electrolytes, and some
vitamins, and forms feces for elimination.
● The rectum stores feces until they are eliminated through the anus.
G. Urinary System
