Term
| What substances do organisms need to keep them alive: 5 |
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Definition
Oxygen (Resirpation).
Glucose (Energy).
Proteins (Hair growth/repair).
Fats (Membranes and energy store).
Water
minerals (Maintain water potentional, enzyme action, metabolism). |
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Term
| How may organisms get the subtances they need: 2 |
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Definition
| Absorb from surrounding enviroment or make them isnide cytosplasm (METABOLISM). |
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Term
| Waste products removed from metabolic activities occuring in an organisms cytoplasm: 3 |
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Definition
C02 (Organisms that arent actively carrying out photosynthesis).
02 (From photosyn in plant cells or protoctist).
Ammonia or urea (excess nirtogen). |
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Term
| As an organism becomse bigger what happens to its surface-area-to-volume ratio: |
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Definition
| It decreases meaning larger organisms need a larger area to exchange more substances. They may combine this with a transport system. |
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Term
| What do good exchange surfaces hvve in common: 4 |
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Definition
Large surface area so theres more space for molecules to pass through (by folding walls/membranes).
Thin barriar to reduce diffusion distance.
Fresh supply of molecules on one side to keep concentrationm high.
Removal of required molecules on other side to keep concentration low. (Steep diffusion gradient). |
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Term
| Definition of exchange surface: |
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Definition
| A specialised area thatis adapted to make it easier for molecules to cross from one side of the surface to the other. |
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Term
| Examples of exchange surfaces IN an organism: |
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Definition
Small intestine (Nutrients absorbed).
Liver (Levels of sugar in blood adjusted).
Root hairs of plants (Water and minerals absorbed).
Hyphae of fungi (Nutrients absorbed). |
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Term
| Definition of gaseouse exchange: |
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Definition
| Movement of gases by diffusion between an organism and its enviroment across a barrier such as alveolus wall. |
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Term
| How does air reach a place where gaseous exchange can occur: |
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Definition
| Nose>Trachea>Bronchi>Bronchioles>Alveoli>gas exchange. |
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Term
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Definition
| Oxygen passes from air in alveolis to blood in the capillaries while co2 passes from blood to the air in the alveoli. |
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Term
Whats the size of an alveoli:
Total surface area of the lung exchange surface: |
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Definition
100-300um.
70m2. So many alveoli that it creates a very large exchange surface. |
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Term
| What other benefit does the surface of alveoli have: |
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Definition
| A barriar permeable to o2 and co2. Plasma membranes surrounds e thin cytoplasm of the cells that readily allows diffusion of 02 and co2. |
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Term
| What adaptions is there that reduce the distance the gases have to diffuse (lungs): |
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Definition
Alveolus wall = 1 cell thick
Capillry wall = 1 cell thick
Both walls have squamous cells (thin/flattened).
Capillaries in close contace with the alveolus.
Capillaries narrow so red blood cells squeezed against the wall = closer to air in alveoli and reducing the rate at which they flow plast in the blood.
Total barrier of diffusion = two flatten cells (less than 1um). |
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Term
What is the bloods role: (conc. gradients).
The hearts role: |
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Definition
Brings co2 from tissues>lungs (conc. gradient of co2 higher in blood than lungs).
Carries o2 away. (Conc higher in lungs of o2 than blood).
Pumps blood along pulmonary artery>lungs. Artery>vessels>capillaries. (1 blood cell wide). |
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Term
What is the breathings role when it comes to concentration gradients:
Venitalion: |
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Definition
Replaces used air with fresh air = assures conc. of o2 in lungs remains higher than that in the blood.
Removes co2 = conc. in alveoli is lower than that in the blood. |
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Term
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Definition
Diapgragm contracts -flattens.
External intercostal muscles contract and ribcage moves down and out.
Volume increases.
Pressure decreases - below atmospheric pressure.
Air moves in. |
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Term
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Definition
Diaphragm relaxes -dome shape.
External intercostal muscles relax and ribcage moves up and in.
Volume decreases.
Pressure increases - above atmospheric pressure.
Air forced out. |
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Term
| What requirements must the trachea, bronchi and brochioles have: 5 |
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Definition
Larger airways = large enough to allow sufficient air to flow without obstruction.
Must divide into smaller airways to deliver air to all the alveoli.
Airways must be strong enough to prevent them collapsing when air pressue inside is low. (Inhalation).
Flexible to allow movement.
Be able to stretch and recoil. |
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Term
Whats more narrow, the trachea or bronchi:
What are their walls like: |
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Definition
Bronchi. But everything else about their structure is pretty much the same.
Relatively thick and have several layers of tissue. |
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Term
| 4 properties of trachea and bronchi walls: |
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Definition
Much consists of cartilage.
In form of incomplete rings or C-rings in trachea (Less in bronchi).
Inside layer of cartilage is glandular tissue, connective tissue, elastic fibre, smooth muscle and blood vessels. 'Loose tissue'.
Inner lining is epithelium layer that has two types of cells. Most have cilia, 'ciliated epithelium. Also goblet cells. |
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Term
| 4 properties of broncioles: |
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Definition
Much narrower than bronchi.
Larger ones have some cartilage.
Wall made mostly of smooth muscle and elastic fibre.
Smallest have cluster of alveoli at their ends. |
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Term
Role of cartilage:
-Supports what and how.
-Preventing what and when.
-How is it still flexible.
-Has some... |
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Definition
Structural role.
Supports trachea and bronchi holding them open.
Collapse during inhilation.
C-rings -can move next without constriction.
Prevents collapse during inhalation.
Some flexibility as doesnt form complete ring. |
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Term
| Why is it important to sometimes constrict the flow of air through the lumen and how does it occur/when: |
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Definition
| If there are harmful substances in the air. Smooth muscle contracts, and isnt voluntary. Can occur during an allergic reaction. Asthma! Bronchioles contract due to a substance in the air. |
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Term
Role of smooth muscle:
-How does it reduce air passing through. |
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Definition
| Can contract to constict airway - makes lumen narrower. |
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Term
Role of elastic fibres:
What happens to it when the smooth muscle contracts and relaxes.
Helps to... |
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Definition
Deforms (loose tissue)and then recoils to origional shape and size.
To dilate (widen) airway. |
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Term
Role of goblet cells and glandular tissue:
-Secrete what.
-For what purpose.
-Such as...
-To reduce. |
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Definition
Secrete mucus.
Traps tiny particles from the air.
Pullen and bacteria.
Reduces risk of infection. |
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Term
Properties of ciliated epithelium:
-Made up of...
-How do they move, and in order to do what...
-What happens to the mucus. |
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Definition
Ciliated cells with numerous tiny hair like projections from their membrane.
Move in synchronised pattern to waft mucus up airway to back of throat.
Music swallowed and acidity in stomach kills any bacteria. |
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Term
How often does air move in and out of your lungs when relaxed:
Why might you breathe more deeply or faster: |
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Definition
About 12 times per minute.
If scared or exercising. |
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Term
Elements of lung volume:Trace diagram
-Tidal volume.
-Vital capacity.
-Residual volume.
-Dead space.
-Inspiratory reserve volume.
-Expiratory reseve volume. |
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Definition
Volume of air moved in and out of lungs at rest. 0.5dm3
Largest volume of air that can be moved into/out of lungs. 5dm3.
Volume of air that remains in lungs after exhalation. 1.5dm3.
Air in bronchioles, bronchi and trachea.
How much air can be breathed in over and above tidal volume.
How much can be breathed out.. |
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Term
| How does a spirometer work: |
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Definition
Chamber of o2 floats on tank of water.
Person breathes in from moouthpiece to tube connected of medical grade o2. Chamber sinks. Breathing out rises chamber. Movement of chamber recorded using a datalogger to produce a trace. |
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Term
What can happen if someone breathes in and out of the spirometer for a long period of time:
How is this avoided: |
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Definition
Level of co2 decreases - dangerously.
Soda limeabsorbs co2 thats exhaled. So total volume of gas will decrease. |
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