Best A&P II Digestive System Exam Review 2026

Beumont's Discoveries

1. The stomach's extremely strong acids and muscular contractions break down food.
2. Some foods are more or less digestible than others.
3. The brain can affect the stomach.

The structure of the mouth

1. The roof of the mouth is formed by the anterior hard palate.
2. The flexible posterior soft palate is anchored to the tongue by the palatoglossal arches, and to the throat by the palatopharyngeal arches, which combined form the boundary between the mouth and throat. It closes off when we swallow so food does not go up the nasal cavity.
3. The uvula is located behind the posterior soft palate.
4. Adults have about 32 teeth. They include the incisors in the front. The canine are pointy. The two teeth after the canines are premolars and we have 3 molars.

Uvula

soft tissue hanging from the middle of the soft palate

Adult Teeth

Adults have about 32 teeth. They include the incisors in the front. The canine are pointy. The two teeth after the canines are premolars and we have 3 molars.

Bolus

The lump of chewed food, right before it is swallowed.

Salivary Glands - 3 types

The parotid glans which are mostly serous. The Sublingual glans, which are mostly mucous, and the submandibular glands which are mostly serous. The produce 3-4 liters per day. Saliva is 97-99% water with a pH of 6.75 to 7.

Amalase

enzyme that breaks down starch

Passage from mouth to esophagus

Food passes from the mouth through the oropharynx and then into the laryngopharynx

stomach structure and function

The Stomach is capable of holding 2-4 liters of material. It is very stretchy. The stomach is lined with the mucosa, submucosa, muscularis externa and serosa, just like most of the digestive system. The muscularis is an additional layer of smooth muscle giving it extra strength.
The inner mucosa of the stomach is extensive. The mucous keeps the stomach from breaking itself down. It is lined with gastric pits and gastric glands. The glands have certain secretory cells like the parietal cells that release hydrochloric acid.

parietal cells

secrete HCl

enteroendocrine cells

release serotonin and histamine which act locally to stimulate other cells contract, or release acid.

chief cells

-Secrete pepsinogen.
It becomes pepsin, an enzyme which helps digest protein.

G cells

-Secrete gastrin.
Most signals that increase stomach activity get the job done by increasing the secretion of gastrin.

3 phases of digestive regulation

a. Cephalic phase
b. Gastric phase
c. Intestinal Phase

cephalic phase of digestion

jThe brain starts the digestive process when we see, smell, taste or think about food. The signal is sent to the hypothalamus, through the medulla oblongata, across the parasympathetic fibers in the vagus nerves and then to the stomach. It is a conditioned reflex. It only works when we want to eat.

Gastric Phase

Once we eat our stomach expands. Stretch receptors are activated. When the signals travel to the brain and back, this is known as the long reflex arc. The signals also zip around within the stomach's own nervous system, known as the short reflex arc.

Intestinal Phase

Speeds or slows the rate at which the stomach empties so as not to overload the small intestine. The only things absorbed into the blood stream from the stomach are caffeine, alcohol, nsaid pain relievers and a few other things