Module 3 Section 1 - Exchange and Transport Flashcards
Pyper
Describe the difference in the appearance of microvilli and cilia.
There’s none - it’s a trick question.
Microvilli and cilia look the same under a microscope
What five things do organisms need to survive? Explain why.
I need to learn two in particular which I’m weaker at.
- Minerals to maintain water potential gradient (osmoregulation) and enzyme action
- Fats to synthesise membranes & as an energy store
- Proteins for growth and repair (and enzymes)
- Oxygen for aerobic respiration
- Glucose for respiration as a source of energy
How do fish gills have a good blood supply?
They have a good network of capillaries
How does a good blood supply maintain a steep concentration gradient?
It removes oxygenated blood, replacing it with deoxygenated blood.
Explain three reasons why diffusion is too slow in multicellular organisms for them to absorb and excrete substances in this way.
- Low surface area to volume ratio - it’s hard for all the substances needed for the organism to survive to diffuse across this smaller space
- High metabolic rate, so oxygen and glucose are used more quickly
- Many cells are deep within the body - large diffusion pathway
How do gills maintain a large concentration gradient?
- Large capillary network
- Well-ventillated - fresh water constantly passes over them
How does good ventillation/blood supply maintain a steep concentration gradient?
There is fast substance removal on the other side, so there’s a high concentration on the outside and low on the inside.
People with emphysema have ____ alveoli in their lungs compared to healthy people.
bigger
Alveoli are covered in ____.
capillaries
How do plants ensure a steep concentration gradient in root hair cells?
The xylem and phloem remove substances from root hair cells and take them up the plant.
How does the small intestine have a large surface area?
There are villi and microvilli which cover these villi - both increase the surface area for nutrient absorption.
What do elastic fibres do in the respiratory system?
They stretch and recoil, allowing expiration to occur (the process of pushing air out of the lungs is passive because of this)
What does smooth muscle do in the respiratory system?
Controls the diameter of tubes (e.g. the trachea, bronchi and bronchioles) regulating the resistance to airflow and so how easily air can move in or out of the lungs
What does cartilage do in the respiratory system?
Connective tissue that is strong but flexible, preventing the trachea from collapsing in on itself when breathing i.e. the tracheal rings provide support
The trachea and bronchi are similar in structure. T/F and why?
True - they have basically the same structure (although the trachea has larger, C-shaped cartillage rings vs. the bronchi having smaller cartillage pieces)
Where is the smooth muscle found?
Between bits of cartilage in the tubes
The cartilage in the bronchi is interspersed with what?
smooth muscle (to control the bronchi’s diameter)
Compare the structures of the trachea and bronchi.
The trachea has larger, C-shaped cartillage while the bronchi having smaller cartillage pieces.
Both the trachea and bronchi have goblet cells, elastic fibres, smooth muscle and ciliated epithelium.
How do the alveoli compare in structure to other parts of the respiratory system?
They don’t have goblet cells, ciliated epithelium, cartilage or smooth muscle - they ONLY have elastic fibres (to stretch for efficient fas exchange).
They are very similar in structure to the smallest bronchioles.
They’re stretchy like balloons !
What is the structure of the largest bronchiole like?
Very similar to the trachea/bronchi, except they don’t have any cartilage.
What is the structure of the smaller bronchiole like?
Very similar to the largest bronchiole, but doesn’t have any goblet cells (or cartilage).
What is the structure of the smallest bronchiole like?
Similar to the smaller bronchiole, but doesn’t have any smooth muscle or ciliated epithelium (or cartillage or goblet cells).
Explain the shape of the cartillage in the trachea.
C-shaped so it doesn’t rub against the neighbouring oesophagus
What do the larger bronchioles possess that the smaller bronchioles don’t? Explain why.
Elastic fibres and smooth muscle - these help change the size of the airway to change the airflow
Describe the parts of the lung where you would find elastic fibres.
Trachea, bronchi, larger bronchioles, smaller bronchioles and alveoli (i.e. all of them)
Describe the parts of the lung where you would find smooth muscle.
Trachea, bronchi, larger bronchioles and smaller bronchioles
Describe the parts of the lung where you would find cartilage, and what this looks like.
Trachea (C-shaped) and bronchi (smaller pieces)
Describe the parts of the lung where you would find goblet cells.
Trachea, bronchi and larger bronchioles
At the cellular level, where are goblet cells found?
Goblet cells are their own cell in between epithelium
Describe the parts of the lung where you would find ciliated epithelium.
Trachea, bronchi, larger bronchioles and smaller bronchioles
Where are the intercostal muscles located?
Don’t think you need to know?
Between the ribs surrounding the lungs
(inter = among/between, costal = ribs)
Where is the sternum located?
Don’t think you need to know?
In the centre of the chest, underneath the heart
What does the sternum do?
Don’t think you need to know?
Protects the heart & lungs and connects bones and muscles together with cartilage
What do the pleural membranes do?
Don’t think you need to know?
Cushions the lung, reducing friction between the lungs, ribcage and chest cavity, and makes breathing easier.
Where are the pleural membranes located?
Don’t think you need to know?
The pleura is a watery tissue that coats the outside of the lungs and walls of the chest/thorax.
breathing in
inspiration
How does passive expiration work?
- Diaphragm relaxes, becomes doming upwards
- External intercostal muscles relax, causing the ribcage to move down and in
- The thoracic volume decreases, increasing the pressure in the chest cavity
- This forces air to flow out of the lungs
How does forced expiration occur?
The internal intercostal muscles contract, pulling the ribcage down and in
Cilia beat mucus ____.
away from the alveoli
1dm3 = ?
1 litre
Explain how the volume of gas in a spirometer changes over time.
The soda lime in the spirometer absorbs/reacts with carbon dioxide produced in respiration. Oxygen is used up in respiration, so the total volume of gas in the spirometer decreases over time.
Why does the spirometer lid move?
To maintain the pressure in the spirometer.
How can the movement of the spirometer lid be helpful?
The lid is connected to a pen or data logger which moves with the lid. The volume of air inhaled and exhaled can be calculated from the distance the lid moves (and so from the spirometer trace created).
How can you measure oxygen uptake directly from a spirometer (without a graph)?
Find the decrease in volume of the spirometer chamber
tidal volume
The volume of air in each breath.
typical tidal volume for a person
4dm3
vital capacity
The maximum volume of air that can be inhaled/exhaled at once.
Describe the counter current system and explain why it is beneficial.
Blood flows one way through the gills, while water flows in the opposite direction.
This means that water with a relatively high oxygen concentration always flows next to blood with a lower oxygen concentration, so oxygen diffusion occurs across the whole length of the gills, and there is a continuous flow of water over the gills.
gill filament
A thin plate that makes up fish gills; primary lamellae
gill plate
Small structures that cover the gill filaments perpendicular to the gill filaments in fish gills; secondary lamellae
gill arch
Bone/cartilage joined to a gill, holding it in place
operculum
Flap of many bones on the side of a bony fish’s head
gill raker
Bony spine attached to a fish gill arch to prevent solid (food) particles from entering the gills
In some bony fish, the operculum bulges out after the floor of the buccal cavity lowers. Suggest why.
This increases the volume of the cavity behind the operculum, decreasing the pressure. This helps water enter he fish’s mouth.
Name the other type of fish (that aren’t bony) and describe how they get oxygen into their blood.
Ram fish - they keep moving through water to force water across their gills.
How might water temperature changes affect gas exchange in fish?
Warmer water -> lower solubility of oxygen (less dissolved gases) -> there’s less oxygen available for diffusion into fish blood
How might pollution affect gas exchange in fish?
Pollution may introduce harmful substances which interfere with the gill’s ability to exchange gases -> decreased efficiency of gas exchange
Why do insects use rhythmic abdominal movements?
This changes their bodies’ volumes and so the pressure in their bodies, causing air to move in and out of the spiracles.
Explain how bees can efficiently use their wings.
Larger insects like bees can use the movement of their wings before or during flight to pump their thoraxes, changing the volume of their bodies and so the pressure, causing air to move in and out of the spiracles.
Bigger insects e.g. crickets can have ____. What is the use of these?
air sacs - they help air to flow through the body and lower the insect’s density for flight
surfactant
A chemical substance that decreases the surface tension between liquid(s) and a solid/gas
Name a part of the body in which a surfactant is needed. Explain why.
Alveoli
A surfactant makes breathing easier because the tissues around the alveoli don’t stick together due to surface tension and cause the alveoli to collapse
How are tracheoles adapted for efficient gas exchange?
They have thin, permeable walls (-> short diffusion pathway) and go to individual cells. They also have a large surface area.
What do spiracles look like?
They’re pores, and look a bit like stomata
How can you dissect insects?
- Fix insect to dissecting board with dissecting pins (through its legs)
- Cut along the insect’s abdomen to remove a piece of its exoskeleton
- You can use a syringe to fill the abdomen with a saline solution -> can see the silvery treacheae
- You can use a wet mount microscope slide to see the chitin rings in the tracheae walls
Tracheae diameters ____ as you get nearer cells. This is like/unlike humans.
shrink (become narrower), unlike
How do insects maintain aerobic respiration?
Aerobic respiration -> production of (small amounts of) water -> water clogs the ends of the bronchioles -> oxygen is blocked from diffusing into cells -> reduction in oxygen concentration of cells -> anaerobic respiration -> production of lactic acid -> lactic acid decreases the water potential of cells -> water is reabsorbed into the cells by osmosis down the water potential gradient -> aerobic respiration
This cycle repeats - insects like it !
The smooth muscle in the trachea is relaxed when the trachea shrinks/expands.
expands
What is the primary advantage to the insect tracheal system?
It provides oxygen directly to cells that need it (making it efficient)
How do insects primarily control the opening and closing of their spiracles?
Using muscles (not air pressure changes like in mammals/bony fish)
The lugwork is a species of segmented worm that burrows in damp sand. They have hair-like external gills that increase the surface area available for gas exchange.
Many other species of segmented worm don’t have external gills.
Suggest why lugworms have evolved external gills.
e.g. oxygen isn’t abundant in the lugworm habitat
This is a glorified exchange surface question.
Cartilage’s properties are that it is ____ but ____.
strong, flexible
