Digestive System Flashcards
What are the functions of the digestive system?
Motility:
Movement of food through digestive organs while breaking them
Secretion:
release of substances that help food to be digested (enzymes & hormones)
Digestion:
Break down of food into molecules that can fit in the bloodstream
Absorption:
Digested nutrients move from digestive system to bloodstream to be brought to cells
What occurs in mechanical digestion?
Chewing in mouth, teeth, tongue, saliva, etc
Movement and mixing in stomach
What occurs in chemical digestion?
Process where enzymes are involved
Enzymes are molecules that regulate and speed (catalyse) up the rate of chemical reactions in the body
Main enzymes include amylases, proteases, and lipases
Enzymes are destroyed after digestion but are produced every time you digest food
What is motility in detail?
Food moves through digestive tract through process called peristalsis
Movement of muscles in gastrointestinal tract
Breakdown and mixing of ingested nutrients until disposal of waste
What is secretion in detail?
Release of enzymes, hormones, and other substances to digest food
Hormones are chemical hormones that tell the body what digestive juice to produce
What is digestion in detail?
Breakdown of large insoluble molecules into smaller and water-soluble ones
Utilises mechanical and chemical processes
Nutrients include carbs, proteins, etc
What is absorption in detail?
Digested nutrients go from gastrointestinal tract (main pathway of digestive system) into blood
Nutrients keep cells running
Name as many examples of enzymes and the chemical reactions they catalyse.
Maltase: maltose to glucose (carb)
Lactase: Lactose (dairy) to aploctose and glucose
Pepsin: proteins to amino acids
Trypsin: protein to amino acids
Sucrase: sucrose to fructose and glucose
Amylase: carbs into simple sugars
Explain the purposes of different organs in the digestive system.
Mouth: Where mechanical digestion begins
Tongue: Helps move food in the mouth
Liver:
- Detoxification: removing harmful chemicals from the blood
- Production of bile to break down fats
Gall-bladder:
Sac in the liver that has bile (yellowish-greenish)
Pharynx:
connects mouth and nasal passageway to the esophagus. Has a small flap called the epligottis that covers the windpipe to keep food going down the right passage.
Esophagus:
Connects pharynx to stomach as a tube around 20-25 cm long. Food moves through via peristalsis
Stomach:
Muscular, hollow organ in the GI tract. Performs mechanical and chemical breakdown with enzymes and hydrochloric acid
Pancreas:
Secretes hormones into the blood and enzymes through small ducts to help break down food
Small intestine:
Long and narrow tube where where chemicals break down food and absorb it into the bloodstream (6 m long).
Large intestine:
Wide and short tube that absorbs water and gets rid of feces
Rectum:
Part that connects to the anus
Anus:
Exit point of digestive system
How does the liver work?
- In upper right abdomen
- 2 lobes, one can work if other isn’t
- Secretes bile
- Produces proteins like bumin to regulate blood pressure
- Filter substances and toxins
- Lobes made up of 8 segments that consist of 1,000 lobules
- Lobules are connected to small ducts that are connected to larger ones to form the hepatic duct which helps transport what the liver produces
- Only organ that can regenerate
How does the small intestine absorb food?
The small intestine has small projections called villi. Villi increase the surface area for absorption and absorb small molecules of nutrients. The nutrients enter through the blood capillaries and lacteal that bring food throughout the body.
What are the types of teeth that organisms have?
Incisors: 4 in the body, cuts food
Canines: help grip and tear food
Pre-molars: chew and crush food
Molars: grind food
Explain the development of human teeth.
Kids have 20 teeth and adults have 32
Deciduous teeth (baby teeth) develop during embryonic stages and erupt through the gums at 6 months old
All 20 teeth appear at age 2.5 years old
All but molars fall out at age 12 to be replaced by adult teeth
Wisdom teeth are you last set of adult teeth that grow in and appear at ages 17 to 25
Sometimes line up with other teeth but normally don’t as there is not enough space
Give an example of an animal’s teeth structure based on their diet.
Your own example (e.g., tigers have pointed canines to help kill prey)
