A bolus is a ball of food/ a wet food mash created in our mouths by saliva with the help of amylase
What is the PH of the stomach?
2-3
How can pepsin be activated from pepsinogen?
With the addition of HCL
What is pepsin? Where is it secreted from? Where is it located in?
Pepsin is an enzyme that digests proteins. It is secreted from the gastric glands in the stomach. And, it is located in the stomach.
What is the job of hydrochloric acid in the stomach?
To kill bacteria and to activate pepsin (active version of the pepsin enzyme) from pepsinogen (inactive version of the pepsin enzyme).
What is mucus?
Mucus is a protective covering that stops the HCL in the stomach from burning the stomach. Mucus is produced by Mucus cells.
What do the gastric glands in the stomach secrete?
They secrete mucus, hydrochloric acid, and pepsin.
What is an endoscope?
A tube shaped instrument with a tiny lens and a light source that is inserted into the abdominal cavity and can be fitted with a laser to diagnose problems and/or perform surgery.
Explain how an ulcer forms.
If a certain type of bacteria (that destroys the mucus lining in your stomach) gets into your stomach such as H. Pylori, the protective mucus lining keeping the stomach safe from its own HCL breaks down, exposing the capillary network to stomach acid. When this happens, the body thinks that there is a disease in your stomach. So, it releases histamine which increases blood flow and increases acid secretion in order to kill the so called "virus" in your stomach. What this actually does is it actually increases the amount of tissue burned as there is no actual virus in the stomach. It is just a hole in the mucus lining (caused by H. pylori) and adding more acid would just increase the burning. This cycle keeps on going and going. (the body releases more histamine because it thinks the virus is still not dead causing more acid to be released and the cycle keeps going.)
What are the folds in the interior of the stomach called?
Rugae
How many muscle layers does the stomach have. Combined, what do they do?
The stomach has 3 muscle layers. They mix and churn food
What enables the stomach to stretch and contract?
The folds inside the stomach
What are the different sphincters of the stomach and what do they do?
The different sphincters' of the stomach includes the lower esophageal sphincter (the entrance to the stomach) and the pyloric sphincter (the exit of the stomach). The esophageal sphincters' allows bolus's to enter the stomach and the pyloric sphincter controls the flow of chyme into the duodenum.
What are the functions of the stomach?
The stomach connects the esophagus to the duodenum of the S.I., It stores food and starts protein digestion, and it breaks down food with physical (muscle contraction) and chemical digestion (gastric gland).
When the muscles contract in peristalsis is there any gap behind the bolus?
No, this is why when we eat or drink upside down, the food/liquid does not come back out through our mouths'
True or false: When we swallow, the epiglottis blocks the larynx/ the trachea (the windpipe) to prevent food and liquid from getting into our lungs
True
True or false: when we swallow, the epiglottis covers the esophagus.
False
What is the epiglottis?
It is a gate in the throat that controls movement of food to stomach and air to lungs
Explain Peristalsis.
Peristalsis is the contraction of muscles in the digestive tract to push nutrients/ a bolus of food through the digestive tract (as the section of muscle behind the bolus contracts, the section in front relaxes, pushing the bolus/the nutrients through the digestive tract, kind of like a human squeezing a tube of toothpaste.)
What is the function of the esophagus?
To involuntarily transport bolus of food from the mouth to the stomach by rhythmic muscle contraction called peristalsis
What is the difference between physical/mechanical digestion and chemical digestion?
Physical/mechanical digestion turns big chunks of food smaller (breaks down food) without breaking any chemical bonds. Meanwhile, chemical digestion involves breaking chemical bonds to break down food
What are the three types of teeth? What is the function of each type?
The three types of teeth include the incisors, the canines, and the premolars and molars. The incisors cut, the canines tear, and the and the premolars and molars grind.
What do teeth do?
Teeth physically digest food (breaks food into smaller pieces)
What is the purpose of saliva in our mouth?
To form a bolus (along with amylase), to activate our taste buds, and to lubricate the digestive tract.
What do the salivary glands do?
They produce the amylase enzyme (for carb digestion) and they also produce saliva.
What is another name for the mouth?
The oral cavity.
What is the sequence of how things such as nutrients or food travel through our digestive system
mouth, esophagus, stomach, small intestine, large intestine, rectum, anus.
What is egestion?
Egestion is the removal of undigested material
What is absorption in the digestive system?
When cells take up small molecules such as monosaccharides, amino acids, glycerol, or fatty acids
What is enzymatic hydrolysis?
Enzymatic hydrolysis is a process in which enzymes facilitate the cleavage of bonds in molecules with the addition of the elements of water
What is digestion?
Digestion is the process of food break down (enzymatic hydrolysis)
What is ingestion?
Ingestion is the act of eating
True or false:
The longer the digestive tract, the less of a chance for absorption of nutrients
False
How long is the digestive tract?
6.5 to 9m long.
What happens to nutrients in the digestive tract?
They are broken down and absorbed in the digestive tract.