The Digestive and Respiratory Systems

For the record, there are only 2 quizzes left in anatomy! Hooray!!! Okay, you can do your happy dance now. Time really flies when you are learning alot and working hard. We definitely do alot of work and learning in this class, especially memorizing. Just think, ever since this class started, you now know so much more than the average person. You can name the bones, the muscles and describe what happens during fetal circulation!!! Not many people can do that. You deserve a pat on the back!!! This week, our focus is on the Respiratory and Digestive systems. Looking at the terms, it may seem like a mouthful, but these structures are so much fun and there is much application to help in your learning.

The Respiratory and Digestive systems are amazing machines. Just think, without the respiratory system, you would not be able to wake up in the morning and smell the fresh morning air. Without the Digestive system, you would not be able to eat the foods you love!!! Now I love to eat, and what a sad world it would be if we could not enjoy the tastes from around the world. These two systems help us to enjoy alot of the simple things in life. Never take for granted the wonderful things your body allows you to do and experience. Now, here are some interesting facts to wrap your brain around:

The Respiratory System

• Our nose hairs help clean and warm the air that we breathe.
• The right lung is slightly larger than the left lung.
• The surface area of the lung is roughly the size of a tennis court.
• The capillaries in the lungs would extend 1600 kilometers if placed end to end.
• We lose half a liter of water a day through breathing. This is the water vapor we see when we breathe onto glass.

The Digestive System

• Two pints of saliva are produced each day.
• Muscles in the digestive tract contract in waves to move food along. So if you are standing on your head, food will still end up in your stomach.
• The small intestine is three grown men tall and two fingers wide.
• Food stays in your small intestine anywhere from one to four hours.
• We eat about 500 Kg per year
• The Pancreas produces digestive juices and helps in controlling blood sugar
• The Gall Bladder stores bile which helps in the digestion of dietary fat

**Now for some memorizing tid bits for the week!!!

Conducting Passages

Choanae: space between the nasal cavity and nasopharynx

Pharynx: divided into three regions

• nasopharynx: starts at the choanae and ends at the uvula (in the nasal region)
• oropharynx: starts at the uvula and ends at the level of the hyoid bone (think oral region)
• laryngopharynx: starts at the hyoid bone and ends at the bottom of the cricoid cartilage (the region where you find the larynx)

Tonsils: Lymphatic tissue

• tubal tonsil: forms around the opening of the auditory tube. Looks like a candy cane.
• pharyngeal tonsil: located on the posterior wall of the nasopharynx
• palatine tonsil: paired tonsils located at the back of the throat (usually removed)
• lingual tonsil: located on the posterior surface of the tongue (lingual means tongue)

Larynx: Continuous with the trachea; production of sound

• Thyroid Cartilage: big on the anterior side, small on the posterior side. Gives rise to the "Adam's apple."
• Cricoid Cartilage: small on the anterior side, big on the posterior side.
• Arytenoid Cartilage: superior to the cricoid cartilage on the posteior side. Forms a triangle and serves as attachment site for vocal cords
• Epiglottis: tissue that closes off the wind pipe to prevent choking

Mechanics of Pulmonary Ventilation

Internal Intercostal Muscles: can found on both the anterior and posterior sides of the rib cage. Muscles fibers point in an upwards direction

External Intercostal Muscles: can be found only on the anterior side of the rib cage. Muscles fibers point in a downwards direction.

The Mouth

Salivary Glands

• Parotid: located anterior to the ear. Largest of the salivary glands.
• Submandibular: located under the mandible. Sub in latin means "under"
• Subligual: located under the tongue

Serous Membranes

Mesentary Proper: peritoneum that holds the small intestines in place

Lesser Omentum: tissue that comes off of the lesser curvature of the stomach

Greater Omentum: tissue that comes off of the greater curvature of the stomach. Known as the apron that drapes over most of the abdominal organs.

Gastrointestinal Tube

Stomach

• Cardiac Sphincter: juction between the esophagus and the stomach
• Cardiac Region: region of stomach attached to the esophagus
• Fundus: dome shaped part of the stomach
• Body: middle region inferior to the fundus
• Gastric Rugae: folds on the inside stomach wall
• Pyloric Region: terminal portion of the stomach that leads to the small intestine
• Pyloric Sphincter: junction between the stomach and small intestine

Small Intestine

• Three regions; DONT JUMP IN -> Duodenum, Jejunum, Ileum
• Plicae Circulares: folds on the inside walls of the small intestine; contain micro villi
• Ileocecal valve: junction between the ileum and the cecum

Large Intestine

• Tenia Coli: shiny band of longitudinal muscle that runs along the entire large intestine. Acts like a draw sting to propel food along to the rectum.
• Haustra: bulges in the large intestine that is caused by the action of the tenia coli
• Epiploic Appendages: fat accumulations of visceral peritoneum on the large intestine
• Hepatic Flexure: Curve in the large intestine that is by the liver
• Splenic Flexure: Curve in the large intestine that is by the spleen
• Internal Anal Sphincter: inside walls of the anal canal; involuntary smooth muscle
• External Anal Sphincter: outside walls of the anal canal; voluntary skeletal muscle

Liver

• Common Hepatic Duct: fusion of the right and left hepatic ducts
• Common Bile Duct: fusion of the common hepatic duct and cystic duct
• Falciform Ligament: ligament that separates the right and left lobes of the liver