Gas Exchange Flashcards Preview

LS 11 - Life Sciences > Gas Exchange > Flashcards

Flashcards in Gas Exchange Deck (46)
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0
Q

Cellular respiration

A
  • A chemical process taking place inside cells
  • Glucose reacts with oxygen to produce carbon dioxide, water and energy (ATP and heat)
1
Q

Breathing

A
  • Mechanically ventilating the lungs
  • Inhaling oxygen rich air and exhaling carbon dioxide rich air
2
Q

Gas exchange

A
  • A physical process taking place by diffusion
  • Between air in the alveoli and blood
  • Between the blood and tissues of the body
3
Q

Diffusion

A
  • Movement of a substance from a high to a low concentration until equilibrium
  • No energy input required
4
Q

Requirements for efficient gas exchange surface

A
  • thin surface
  • moist surface
  • large surface area
  • protected surface
  • transport system close to surface
  • adequate ventilation
5
Q

Plant large surface for gas exchange

A
  • Spongy mesophyl inside leaves
  • Leaves themselves have a large surface area
6
Q

Earthworm large surface for gas exchange

A
  • Entire body surface can exchange gases
7
Q

Insect large surface for gas exchange

A
  • Tracheal system of branching tubes
  • Ending in tiny channels called tracheoles
8
Q

Fish large surface for gas exchange

A
  • Gills with filaments and lamellae (folds)
9
Q

Plant thin surface for gas exchange

A
  • Gases exchanged directly into leaf cells
10
Q

Earthworm thin surface for gas exchange

A
  • Gases exchanged across columnar epithelium (short distance)
11
Q

Insect thin surface for gas exchange

A
  • Tracheoles very thin permeable walls in close contact with cells
12
Q

Fish thin surface for gas exchange

A
  • Very finely structured gills, water and blood in close contact
13
Q

Moist surface for gas exchange in plants

A
  • Water moves through xylem into the leaf and evaporates by transpiration
14
Q

Moist surface for gas exchange in earthworm

A
  • Epithelium secretes mucus
15
Q

Moist surface for gas exchange in insects

A
  • Exoskeleton prevents insect from drying out
16
Q

Moist surface for gas exchange in fish

A
  • Fish lives in water
17
Q

Ventilated surface for gas exchange in plants

A
  • Leaves exposed, constantly ventilated by air movement
18
Q

Ventilated surface for gas exchange in earthworm

A
  • Surface of worm exposed to air trapped between soil particles
19
Q

Ventilated surface for gas exchange in insects

A
  • Air sacs in tracheal system close to muscles
  • When muscles contract and relax air is drawn into the tubes
20
Q

Ventilated surface for gas exchange in fish

A
  • As fish swim, water flows over gills
  • Operculum also acts as a pump
21
Q

Transport system for efficient gas exchange in plants

A
  • Gases exchanged directly with cells in the leaf
22
Q

Transport system for efficient gas exchange in earthworm

A
  • Worm has a closed blood system with haemoglobin
  • Capillaries close to surface of the skin
23
Q

Transport system for efficient gas exchange in insects

A
  • Oxygen diffuses directly from tracheoles to cells
24
Q

Transport system for efficient gas exchange in fish

A
  • Blood flows in vessels in opposite direction to water flow
25
Q

Protection of gas exchange surface in plants

A
  • Stoma and waxy cuticle protect the inside layers of the leaf
26
Q

Protection of gas exchange surface in earthworm

A
  • Protective layer of skin called cuticle
27
Q

Protection of gas exchange surface in insects

A
  • Exoskeleton of insects protects system
  • Openings protected by valves called spiracles
28
Q

Protection of gas exchange surface in fish

A
  • Bony flap called operculum covers gills
29
Q

Efficient gas exchange in humans

A
  • Thin: walls of alveoli and capillaries single celled, flattened squamous epithelium
  • Moist: lining of epithelium in alveoli covered in a thin layer of moisture
  • Surface area: millions of alveoli air sacs add up to a large surface area
  • Protection: thoracic cage made up of rib bones and muscles
  • Transport: alveoli supplied by capillaries containing blood
  • Ventilation: breathing system by muscles and rib bones
30
Q

Function of nostrils

A
  • Opening to air passages
  • Lined with hairs to remove dust from inhaled air
31
Q

Function of nasal passages

A
  • Lined with ciliated columnar epithelium which secretes mucus
  • Mucus moisten air and filters dust and germs by trapping these
  • Turbinate bones slow air flow so it can be warmed by nearby blood
32
Q

Function of pharynx

A
  • Common to both air and food.
  • Leads to trachea via valve called the glottis
33
Q

Function of the larynx

A
  • Also called the voice box as this contains vocal cords
  • Guards the entrance to the trachea
  • When food swallowed the glottis is closed by the epiglottis to prevent food entering trachea
34
Q

Function of the trachea

A
  • Held open by c-shaped rings of cartilage
  • Lined with ciliated epithelium to remove dust etc.
35
Q

Functions of bronchi and bronchioles

A
  • Trachea divides into bronchi also with cartilage to hold them open
  • Bronchi divide into numerous bronchioles
  • These branch until ending in the alveoli
36
Q

External structure of the lungs

A
  • Cone shaped
  • Base touches diaphragm
  • Pleural membranes (pleura) line the inside of thoracic cavity and the outside of each lung
  • Between pleura is pleural fluid that reduces friction during breathing
37
Q

Internal structure of lungs

A
  • Bronchi subdivide to form bronchioles
  • Smallest bronchioles end in alveoli
  • Walls of alveoli made of flattened squamous epithelium
  • Each alveolus surrounded by a network of capillaries
  • Walls of capillaries have a single layer of endothelium.
  • Pulmonary artery (deoxygenated blood) enters the lung
  • Pulmonary vein (oxygen rich) leaves the lungs
38
Q

Mechanism of inhalation

A
  • Diaphragm contracts and flattens
  • External intercostal muscles contract
  • Internal intercostal muscles relax
  • Rib cage is lifted
  • Internal volume of thoracic cavity increases
  • Internal pressure decreases
  • Air rushes into lungs
39
Q

Mechanism of exhalation

A
  • Diaphragm relaxes and moves up
  • External intercostal muscles relax
  • Internal intercostal muscles contract
  • Rib cage is dropped
  • Internal volume of thoracic cavity decreases
  • Internal pressure increases
  • Air rushes out of lungs
40
Q

How is oxygen transported

A
  • Oxyhaemoglobin (98,5%)
  • Dissolved in blood plasma (1,5%)
41
Q

How is carbon dioxide transported?

A
  • Bicarbonate ions (70%)
  • Carbaminohaemoglobin (23%)
  • Dissolved in blood plasma (7%)
42
Q

Gas exchange in the lungs after inhalation

A
  • Alveolus has a high concentration of oxygen and a low concentration of carbon dioxide
  • Blood capillaries have a high concentration of carbon dioxide and a low concentration of oxygen
  • The oxygen diffuses from the alveolus into the blood
  • The carbon dioxide diffuses in the opposite direction from the blood into the alveolus
43
Q

Gas exchange in the tissues

A
  • Blood arriving at the tissues has a high concentration of oxygen.
  • The tissues have a high concentration of carbon dioxide.
  • The oxygen diffuses from the blood into the tissues.
  • The carbon dioxide diffuses in the opposite direction from the tissues into the blood.
44
Q

Composition of inhaled vs exhaled air

A
  • Inhaled oxygen 21% vs. exhaled oxygen 16%
  • Inhaled carbon dioxide 0,04% vs. exhaled carbon dioxide 4%
  • Nitrogen stays the same at about 79%
  • Water vapour increases
45
Q

To be continued…

A

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