Science Focus 4.5 Flashcards

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1
Q

A ________ system is needed to provide oxygen to, and remove carbon dioxide from cells.

A

respiratory

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2
Q

Although air can sometimes enter the respiratory system through the mouth, most inhaled air enters via the nose. Here it is ________, ______ and ________.

A

filtered; warmed; moistened

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3
Q

Nostril hairs filter out larger particles, and tiny hairlike _____ on the inside of the nose trap fine particles.

A

cilia

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4
Q

The nose is lined with _____ ______ that produce sticky _____ to trap dust particles.

A

mucus glands; mucus

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5
Q

The mucus and trapped particles move to the back of your nose and into the ______. We swallow around ___ millilitres of this mucus per day without usually being aware of it.

A

pharynx; 600

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6
Q

From the pharynx, air enters the ______ (windpipe), a thin-walled tube with about the same diameter as a garden hose.

A

trachea

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7
Q

At the top of the trachea is the ________, a flap of tissue, stops food entering the trachea. The _____ (voice box) also helps stop food entering.

A

epiglottis; larynx

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8
Q

________ and ________ are both reflexes to further protect the trachea.

A

Coughing; sneezing

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9
Q

The trachea branches into two main ______, which branch successively into smaller and smaller tubes.

A

bronchi

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10
Q

At the end of the smallest of these tubes (________), air enters clusters of sacs, the _______. Gas exchange in and out of the blood takes place here.

A

bronchioles; alveoli

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11
Q

The entire system of tubes is lined with _____, which beat upwards to send foreign material back to the pharynx to be coughed out or swallowed.

A

cilia; pharynx

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12
Q

Alveoli are sacs with walls only one cell thick. There are around _________ of these in your lungs, with a total surface of about __ square metres.

A

500 million; 80

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13
Q

Each alveolus lies close to the wall of a _______. These are also one cell thick, so there is only a short distance for gases to travel between the lungs and the bloodstream.

A

capillary

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14
Q

The network of capillaries in the lung is so large that at any one time __ per cent of the total blood volume is in the lungs.

A

20

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15
Q

Inside the alveoli, oxygen moves across through the thin walls of the tiny capillaries and into the blood. Once in the blood, oxygen is carried by red blood cells in a special carrier called _______.

A

haemoglobin

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16
Q

Haemoglobin allows much more ______ to be carried in blood than if it was simply dissolved.

A

oxygen

17
Q

Dissolved waste gas - ____________ - comes out of the capillaries back into the alveoli, ready to be breathed out.

A

carbon dioxide

18
Q

Replacement of the air is the result of ________ which is a physical process and is clearly different from respiration, which is a chemical reaction.

A

breathing

19
Q

Normally, you breathe without thinking about it, but you can alter the rate and depth of breathing with ______ ______.

A

conscious effort

20
Q

Take a deep breath. Notice that your ribs move up and out. This occurs due to the action of muscles in the chest (the ________) and the ________.

A

intercostals; diaphragm

21
Q

The diaphragm is the sheet of muscular tissue that separates the chest from the _____.

A

abdomen

22
Q

Simple single-celled (unicellular) organisms can exchange _____ directly with their watery surroundings through their cell walls or membranes.

A

gases

23
Q

Many aquatic animals use _____.

A

gills

24
Q

Flattened, worm-like animals often use their ____ _______ for gas exchange.

A

body surface

25
Q

Most true air-breathers have lungs but some, like the frog, use their _____ for additional gas exchange.

A

skin

26
Q

Human skin also breathes but accounts for only ____ per cent of our total gas exchange between air and blood.

A

0.06

27
Q

Insects do not have lungs or blood vessels, but use a system of ________ _____ for gas exchange.

A

airfilled tubes