Organisation Flashcards
Order the levels of organisation within a multicellular organism. Start from the most simple level.
Cell Tissue Organ Organ system Organism
What do glandular tissues do?
Produce enzymes and hormones
What are epithelial tissues?
Tissue on the outside of the body
What is an organ?
An organ is a group of different tissues that work together to carry out a special function
What is the stomach an example of? What 3 tissues is it made of?
The stomach is an organ. It consists of glandular, muscle and epithelial tissue.
What are the two types of digestion?
Physical (mechanical)
Chemical
What sort of enzymes are used to break down food?
Digestive enzymes
Define digestion
Digestion is the breaking down of large insoluble food molecules into smaller, simpler, soluble ones.
food that has been digested and has become soluble, where does it go?
It diffuses into the bloodstream
What is physical digestion? Why is it useful? What are the two ways it occurs?
1) physical digestion breaks food into smaller bits, the surface area increases.
2) It aids chemical digestion by enzymes, as there is a larger surface area to work with.
3) chewing and peristalsis
Where does peristalsis occur (3 places)?
Walls of oesophagus, the stomach and intestines
Where is bile produced and what does it break down?
Bile from the gall bladder breaks fats down into smaller oils.
What is chemical digestion and what is required for it to occur? What change does the food undergo?
It is the breaking down of large insoluble molecules into smaller soluble ones. Enzymes are required, therefore the food is chemically changed.
What happens to food in the mouth? Mention 3 points (out of 6)
1) The tongue and teeth break the food up into a bolus
2) Salivary glands secrete saliva
3) The saliva has water to dissolve soluble substances
4) The saliva has mucus for lubrication
5) The saliva has lysozyme to kill bacteria
6) The bolus is swallowed through the pharynx
What happens to food in the oesophagus?
What are some of the key features? (Mention 3)
1) A thin muscle layer propels food by peristalsis, a wave of circular muscle contraction, which passes down the oesophagus. Mucus is secreted from a few glands.
2) it is a simple soft tube through the thorax, can be closed, no villi, thin epithelium, a few glands and it connects the mouth to the rest of the gut.
What happens in the stomach? (Summarise at least 3 of the points)
In the stomach:
Food is stored for a few hours
1) Gastric juices are secreted, contains hydrochloric acid to kill bacteria
2) Protease enzymes present so proteins are digested here
3) Muscle churns food into chyme (liquid)
4) Chyme is gradually released into the small intestine by the sphincter (a small muscular ring)
Describe 4 key features of the stomach. (What is it?)
Expandable bag No villi A number of gastric pits Mucus to lubricate food Epithelial lining to protect from acid 3 layers of muscle Has the enzymes pepsin and rennin (protease enzymes)
What are the three sections of the small intestine?
Duodenum (connected to stomach)
Jejunum (middle)
ileum (attached to large intestine)
Describe the small intestine (make 3 points)
3 sections: duodenum, jejunum & ileum
Over 6-7m long
Majority of chemical digestion done in the duodenum
Thin inside wall, large surface area
Inner wall is lined with villi
Good blood supply
Short diffusion distance to blood vessels
Muscular walls
Middle third has ducts which pas through bile & pancreatic juices
What happens in the small intestine?
Food passes through the three sections, digested food molecules are absorbed in the small intestine and passed to the bloodstream. The muscular walls squeeze any undigested food onto the large intestine.
Give three adaptions in the small intestine and explain what they do to aid digestion. (6 possible adaptations)
1a) The inside wall is thin 1b)The inside wall is lined with villi (surface area)
1) both adaptations allow absorption to happen quickly and efficiently.
2a) Good blood supply 2b) short diffusion distance to blood vessels
2) both adaptations make it easier for food molecules and other substances to be exchanged between the blood and the small intestine
3) The middle third has ducts which are adapted to pass bile and pancreatic juices through. The enzymes break down the food.
4) muscular walls make it possible to squeeze undigested food onto the large intestine
Fill in the blanks:
The large intestine starts with the ca——, then the ap——, then the a—— colon, then the d—— c—— and it ends with the r——. It is about 1.5m long! It contains v——i but no mi——, there are many gl—— secreting mucus.
*note (the random letters are the beginnings of words, basically a clue for me)
The large intestine starts with the caecum, then the appendix, then the ascending colon, then the descending colon and it ends with the rectum. It is about 1.5m long! It contains villi but no microvilli, there are many glands secreting mucus.
Caecum, appendix, ascending, descending, colon, rectum, villi, microvilli, glands
Mention 2 points of what happens to food in the large intestine
Any points from this description:
Food can spend 36 hours in the large intestine, while water is absorbed from food into blood. The material left over forms semi-solid faeces.The faeces is released by the anal sphincter (which we can thankfully control 😅).
Name three of the things that faeces 💩 is made from
Plant fibres (mainly cellulose) Cholesterol Bile Mucus Mucosa cells from the lining of the large intestine Bacteria Water
What is the use of vitamins in the body
They convert food to energy and assist bodily functions
Which foods would provide protein? Grapes Waffles Egg Custard Lentils
Lentils and egg
What chemical elements are in Carbohydrates, Lipids and Proteins?
Carbon, Hydrogen and Oxygen
Which smaller sub units form lipids ?
Fatty acids and glycerol
Which smaller sub units form proteins?
Amino acids
Which smaller sub units form carbohydrates?
Simple sugars, like glucose and maltose
What enzymes made from?
Enzymes are large protein molecules, they are made up of long chains of amino acids. The amino acids fold to produce an active site