State the function of the stomach in the digestive process. [6]
- J-shaped organ with 4 layers that contract to break down food.
- Secretes gastric juices to chemically break down food (a mix of enzymes, acid, and mucus).
- Protein digestion starts in the stomach with pepsin.
- No lipid or fat digestion.
- Breaks down food with chyme, a mix of gastric juice and food.
- Pyloric sphincter controls flow of food leaving the stomach.
In which section of the small intestine are most nutrients absorbed?
The ileum.
What is the pH of the mouth?
7
Enzymes commonly have _____ at the end.
“-ase”.
______ are the main source of energy for the body.
Carbohydrates
What do vitamins help to control? [3]
Cell functions, growth, and development.
What happens in the jejunum of the small intestine?
The middle section of the small intestine, with some digestion and absorption, and more folds and intestinal glands.
All enzymes are…
…proteins.
State the function of the small intestine in the digestive process. [4]
- Most digestion and absorption of nutrients happen here.
- Folded to increase surface area.
- Lined with villi which are then lined with microvilli. Inside a villi is a complex network of capillaries that allow nutrients to enter the circulatory sysem.
- Villi can’t absorb fats, which are absorbed by lacteals and transported through the lymphatic system.
Proteins are made up of long chains of smaller molecules called…
…amino acids.
What will occur if not enough water is absorbed in the large intestine?
Constipation.
What is the correct order of the four main steps in human digestion?
Ingestion, digestion, absorption, and egestion.
Explain the difference between saturated fats and unsaturated fats.
Unsaturated fats are usually liquid at room temperature, while saturated fats are usually solid at room temperature.
What prevents food from entering the lungs from the esophagus?
The raising of the larynx against the epiglottis.
Give two examples of minerals necessary for proper bodily function.
Calcium for bones, and iron for hemoglobin (oxygen transport in the blood).
The digestive system is also commonly referred to as…
…the gastrointestinal tract.
The ——- sphincter controls the flow of food leaving the stomach.
Pyloric
How many types of amino acids are there? How many are produced by our body and how many must be obtained?
There are 20 amino acids. Our body can produce 12, but the other 8 must be obtained.
The pH of the small intestine is…
…8
Which vitamins are fat soluble and which vitamins are water soluble?
Vitamins A, D, E, and K are fat soluble and vitamins B and C are water soluble.
State the function of the esophagus in the digestive process. [3]
- Lined with circular of longitudinal muscles that aid in peristalsis.
- Mucin further lubricates food.
- Ring of sphincter muscles control the flow of food into or out of the stomach.
What is the difference between endothermic and ectothermic organisms?
Endothermic organisms generate their own body heat and require significantly more food than ectothermic or cold-blooded organisms.
State the function of the large intestine in the digestive system.
- Digestion is complete and most nutrients absorbed.
Caecum: blind end of large intestine by a valve.
Appendix: no role in digestion.
Colon: water and minerals are absorbed. Intestinal bacteria break down some undigested food.
Rectum: Storage of feces.
Anal Canal: anus (anal sphincter).
Egestion: removal of waste food materials from body.
Where are water soluble vitamins stored, and how are they removed?
Water soluble vitamins cannot be stored, and excess is removed through the urine.
