Topic 3 - Organ Systems Flashcards Preview

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Flashcards in Topic 3 - Organ Systems Deck (51):
1

What evidence is there for evolution?

Fossils
Pentadactyl limb

2

why do fossils provide evidence of evolution?

They are traces of plants and animals that lived long ago.

3

how are fossils formed?

Minerals replace teeth shells bones etc to form solid rock-like things.
Buried in soft material which leaves an impression when material hardens
preserved in something because conditions prevent microbes from working. e.g glacier, peat bogs, amber.

4

what do fossils found in rock layers tell us?

what creatures looked like
how long ago they existed
how they've evolved, by studying the differences in different aged rocks we can see the ways they've changed

5

how does the pentadactyl limb provide evidence for evolution?

it is a limb with five digits.
many species have it
the pentadactyl limb in each species has a similar bone structure.
It shows that we have evolved from a common ancestor.

6

what is growth?

an increase in size or mass.
Size is something you measure like height, length, width, or circumference.
Wet mass is the mass of of an organism with all the water in its body.
Dry mass is the mass with no water in.

7

what are tissues??

a group of similar cells that work together to carry out a particular function

8

What are organs?

A group of different tissues that work together to carry out a particular function

9

what are organ systems?

a group of organs working together to perform a particular function

10

what is the journey of blood through the heart?

body - de-oxygenated - vena cava - right atrium - right ventricle - pulmonary artery - lungs - oxygenated - pulmonary vein - left atrium - left ventricle - aorta - body

11

what do valves do?

prevent the back flow of blood

12

What do red blood cells do?

they carry oxygen round the body from the lungs

13

why do red blood cells have a biconcave disc shape?

it gives it a large surface area for absorbing oxygen.

14

What does the haemoglobin do?

it contains iron.
In the lungs it combines with oxygen to become oxyhemoglobin and in body tissues the reverse happens to release oxygen to the cells.

15

What does a lack of iron cause?

anaemia which is when the body can't carry enough oxygen

16

how do white blood cells defend against disease?

They change shape to destroy unwelcome microorganisms.
Produce antibodies to fight microorganisms
produce antitoxins to neutralise toxins

17

What does a low white blood cell count result in?

increased risk of infection

18

what does a high white blood cell count mean?

you have an infection or leukaemia

19

What are platelets and what do they do?

they are small fragments of cells.
They help the blood clot at a wound to stop blood pouring our and microorganisms getting in.
Lack of platelets can result in excessive bleeding and bruising.

20

what is plasma

pale yellow liquid that keeps the blood fluid and transports things.

21

What does the plasma transport

red blood cells
white blood cells
platelets
nutrients such as glucose and amino acids
carbon dioxide
urea
hormones
antibodies and antitoxins

22

What are the three blood vessels?

artery
veins
capillaries

23

what is the function and characteristics arteries?

carry blood away from the heart.
they pump blood out at high pressure so the artery walls are strong and elastic.
the walls are thick compared to the size of the lumen (hole in the middle) they contain thick layers of muscle to make them strong.
branch into capillaries.

24

What is the function and characteristics of veins?

Carry blood to the heart.
Blood is at a low pressure in the veins so the walls don't need to be as thick as arteries.
Bigger lumen than arteries to help the blood flow.
Have valves to help blood flow the right way.

25

What is the function and characteristics capillaries?

involved in the exchange of materials with the tissues.
really small, too small to see.
Carry blood close to each cell in the body to exchange substances with them.
Permeable walls so diffusion can happen. supply food and oxygen and take away waste like co2.
Walls only one cell thick which increases the rate of diffusion whilst decreasing the distance over which it occurs.
join up to form veins.

26

which molecules are too big to pass through the walls of the digestive system?

starch proteins and fats

27

Which molecules are small enough to pass through the walls of the digestive system?

sugars, amino acids, glycerol, fatty acids

28

Which enzymes breaks down starch

carbohydrases (amylase) digests starch into sugars

29

which enzymes break down protein?

proteases (pepsin) protein -> amino acids

30

which enzymes breaks down fat?

lipase
fat -> fatty acids and glycerol.

31

what organs are involved in digestion

mouth
Oesophagus
stomach
liver
gall bladder
Pancreas
small & large intestine

32

function of mouth in digestion

food is moistened with saliva which contains amylase so breaks down starch.
Food is chewed and broken into smaller pieces to form a bolus before being swallowed.

33

function of oesophagus in digestion

tube that takes food from the mouth to the stomach. Lined with muscles that contract to help the bolus move by peristalsis.

34

Function of stomach in digestion

pummels food with muscular walls
produces protease enzymes pepsin
produces HCl to kill bacteria and give the right pH for protease

35

Function of liver in digestion

Where bile is produced, it neutralises stomach acid and emulsifies fats

36

function of gall bladder in digestion

bile stored before released into small intestine

37

function of pancreas in digestion

produces protease, amylase, and lipase enzymes into the small intestine

38

Function of small intestine in digestion

produces protease, amylase, and lipase to complete digestion.
food absorbed out of digestive system into body

39

function of large intestine in digestion

excess water absorbed from food

40

What can you use to model the gut

Visking tube

41

Why is visking tubing a good model

it only lets small molecules through
cheaper and easier than using animals gut

42

Why is visking tubing a bad model

guts a lot longer and has a massive surface area so the speed of digestion will be different
not exact

43

What can be used to test for starch

iodine turns from orange/brown to blue/black if starch is present

44

What can be used to test for sugars

Benedict's reagent
blue - green - yellow- orange - brick red

45

How does enzyme concentration affect the rate of reaction

the higher the concentration the faster the rate of reaction up to a point.

46

What is peristalsis

waves of circular muscle contractions push food
waves of longitudinal muscle contractions keep it as a bolus

47

What are the features of villi that make absorption really efficient

Big surface area so that digested food is absorbed much more quickly into the blood
Single layer of surface cells so that digested food diffuses quickly over a short distance
Good blood supply via capillary network to assist quick absorption of digested food

48

What are functional foods

Food that has a health benefit beyond basic nutrition

49

What are probiotics

contain good bacteria that are thought to help keep your digestive system healthy and immune system strong
e.g bifidobacteria, lactobacillus
found in yoghurts and soya milk

50

What are prebiotics

promote growth of good bacteria which can improve health of digestive system and strengthen immune system
e.g oligosaccharides
leeks, onions

51

What do plant stanol esters do

reduce cholesterol and reduce risk of heart disease
added to some spreads and dairy products