a) pulmonary ventilation.
b) internal respiration.
c) externalrepiration.
d) cellular respiration.
2. Which of the following does NOT belong to the conducting prtion of the respiratory system?
a) alveoli
b) bronchioles
c) nose
d) pharynx
The structure which closes off the larynx is the
a) glottis.
b) Adam's apple.
c) epiglottis.
d) vocal cords.
4. Which of the following describes a correct order of structures in the respiratory passeways?
a) pharynx, trachea, larynx, bronchi, bronchioles
b) larynx, pharynx, trachea, bronchiles, bronchi
c) trachea, pharynx, larynx, bronchi, bronchioles
d) pharynx, larynx, trachea, bronchi, bronchioles
The exchange of gases occurs in the
a) trachea.
b) bronchioles.
c) alveoli.
d) bronchus.
The volume of air that can be exhaled after normal exhaltation is the
a) tidal volume.
b) residual volume.
c) inspiratory reserve volume.
d) expiratory reserve volume.
The volume of air in a normal breath is called
a) total lung capacity.
b) vital capacity.
c) tidal volume.
d) residual volume.
Gas exchange in the lungs happens by the process of
a) osmosis.
b) diffusion.
c) exocytosis.
d) active transport.
Most oxygen in the blood is transported
a) as gas dissolved in plasma.
b) asoxyhemoglobin.
c) ascarboxyhemoglobin.
d) as bicarbonate.
The primary chemical stimulus for breathing is the concentration of
a) carbon monoxide in the blood.
b) carbon dioxide in the blood.
c) oxygen in the blood.
d) carbonic acid in the blood.
DIGESTIVE SYSTEM
The human body needs fuel to live. We eat food for fuel. But just getting the food into the body is only a small part of the process. The food must be broken down into chemicals that the body can use. This whole process is called digestion. Some of the organs involved in digestion are the mouth, esophagus, stomach, small and large intestines, gallbladder, pancreas and liver.
Vocabulary
1. fuel
2. digestion
3. to involve
4. esophagus
5. pancreas
Mouth and Teeth
The mouth and teeth are the first step in breaking food down. During the process of chewing, food is shredded and ground. Powerful muscles move the mandible, or lower jaw, while the food is chewed. The front teeth cut the food and the back teeth grind the food.
There are three main parts to the tooth: the root, the neck and the crown. The root is the part inside the jaw. The neck is a narrow connection between the root and the crown. The crown of the tooth is above the gum.
First teeth come in between 6 and 8 age 6, baby teeth are gradually replaced by permanent teeth. There are 32 permanent teeth.
When food is being chewed, saliva is squirted into the mouth. Saliva helps to soften the food. It contains an enzyme that helps break down the starch in the food.
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After chewing, the food is swallowed and passes down the esophagus to the stomach. The esophagus is about ten inches long. The tongue helps push the food to the back of the mouth, and the muscles in the esophagus move the food down the tube.
Traveling Food
The stomach is a sac shaped like a "j" and is about eight inches long. In the stomach, food is mixed with acids. The muscles in the stomach move, which helps break down the food. The stomach is protected from the acid by a lining. From the stomach, the food pulp is sent to the small intestine. Food leaves the stomach a little bit at a time.
The small intestine is the final place for digestion. Measuring about twenty feet in length, the small intestine is one inch in diameter. Digestive juices released in the small intestine finish breaking down the food.
The food is moved along the small intestine in a squeezing motion known as peristalsis. This motion is much the same as squeezing a tube of toothpaste. All of this movement causes the noise when we say our stomach is "growling."
Lining the small intestine are millions of fingers called villi. These absorb the chemicals that we need from the food into the body. It is at this point the food is actually in the body.
Waste products and food that are not absorbed in the small intestine pass into the large intestine. This waste material is called feces. The large intestine is only five feet long but is larger in diameter than the small intestine. The large intestine includes the colon.
In the large intestine, feces are formed from water, undigested food and bacteria. Water is absorbed back into the body so the waste material becomes more solid as it travels through the colon. It may take as long as twenty hours for food to pass completely through the large intestine.
