Exchange and Transport in Animals (not heart or O2/CO2 transport) Flashcards
What does ventilation do?
Maintains the concentration gradient necessary for passive diffusion.
Adaptations of trachea- 2
incomplete C-shaped rings of strong and flexible hyaline cartilage
Smooth muscle contracts for forced exhalation
Adaptations of Nasal cavity - 3
Large surface area and good blood supply.
Goblet cells secrete mucus
Moist surfaces (due to mucus)
Adaptations of bronchi- 3
Cartilage supports shape
smooth muscle helps control diameter
nerves of parasympathetic (slows down) and sympathetic (speeds up) nervous systems control muscle relaxation and contraction
Adaptations of bronchioles- 2
smooth muscle controls diameter
lined with cilia and goblet cells
Adaptations of alveoli- 6
Very flattened epithelial layer - 1 cell thick
Good blood supply
Collagen to strengthen
Elastin for recoil
Huge numbers to maximise SA
Covered with layer of fluid to dissolve gases
Surfactant
Prevents collapse and allows inflation, ensures balanced surface tension.
Role of smooth muscle in asthma
and asthma treatments- 2
Cells lining bronchioles release histamines (chemicals make epithelial cells inflamed and swollen), stimulating goblet cells to make excess mucus and smooth muscle in bronchiole walls to contract. - airways narrow and fill with mucus.
Relievers- chemicals attach to active sites of surface membrane of smooth muscle cells in bronchioles, making them relax and dilate airways.
Preventers- (often steroids) taken everyday reduce sensitivity of airway linings
What does ventilation do?
Maintains the concentration gradient in alveoli necessary for passive diffusion by constantly cycling fresh air. O2 levels high and CO2 levels low in alveoli.
Three ways we can measure ventilation.
Observation/ counting breaths per minute
Chest belt and pressure meter
Spirometer
Are inspiration and expiration active or passive processes?
Inspiration = active Expiration= considered passive
Inspiration: External intercostal muscles Internal intercostal muscles Diaphragm Air pressure in lungs Air movement(along pressure gradient) Lung volume
External intercostal muscles: contract, pulling ribs UPWARDS and OUTWARDS
Internal intercostal muscles: relaxed
Diaphragm: muscles contact, causing diaphragm to flatten
Air pressure in lungs: decreases
Air movement(along pressure gradient): air moves into lungs
Lung volume: increases
Expiration: External intercostal muscles Internal intercostal muscles Diaphragm Air pressure in lungs Air movement(along pressure gradient) Lung volume
External intercostal muscles: relax
Internal intercostal muscles: contract, pulling ribs INWARDS and DOWNWARDS
Diaphragm: muscles relax, causing diaphragm to curve upwards
Air pressure in lungs: increases
Air movement(along pressure gradient): air moves out of lungs
Lung volume: decreases
What happens during forced exhalation?
Internal intercostal muscles contract and abdominal muscles contract, pushing diaphragm upwards.
What feature of tissues also aids expiration?
Elastic recoil of tissues (bronchi/bronchioles) aids expiration.
What causes ventilation? (not muscles)
pressure gradient
Ventilation equation with units
pulmonary ventilation (dm3min-1) = tidal volume (dm3) x ventilation rate (min-1)
Considerations when using a spirometer
- Closed system- created by water
- Use of a nosepiece
- Patient health
- Sodalime absorbs CO2 (will cause trace to go down)
- Counterbalance removes resistance for breathing
Which part of a spirometer is mobile?
The upper half which is full of oxygen.
What is the lower half of a spirometer tank full of?
Water
Will the trace on a spirometer rise or fall when the patient breathes in?
fall
What is vital capacity?
Volume of air that can be exchanged via the lungs via a maximal inhalation and exhalation.
What is residual volume?
Volume of air that is always present in the lungs.
What is tidal volume?
Volume of air that is exchanged via normal breathing. (one breath)
What factors contribute to a person’s lung capacity/ventilation rate?- 3
Height
Location
Lifestyle
What is emphysema?
Abnormal enlargement of the alveoli, forming air spaces and lowing the overall SA.
Most commonly caused by smoking.
What does an insect’s tough, waxy exoskeleton do and what is its effect on gas exchange?
Protects tissues and prevents water loss. There is little or no gas exchange over its surface.
What is the name of an insect’s specialised gas exchange system?
the Tracheal System
What are the components of the Tracheal System?- 4
Spiracles, trachea, tracheoles, tracheole fluid
In resting insects, how does air move and what happens to tracheole fluid?
Air moves along trachea and tracheoles by diffusion alone. It dissolves in the moisture of walls of tracheoles and diffuses into surrounding cells. (usually adequate due to large SA)
Tracheole fluid seeps into tracheoles from surrounding fluid.
During activity, how is gas exchanged (including what happens to tracheole fluid) in insects?
Oxygen demand increases and lactic acid builds up in cell, lowering water potential. Water leaved tracheoles to tissues via osmosis.
What effect does movement of tracheole fluid during respiration have? Insects- 2
Tracheole fluid moves via osmosis into tissues, taking O2 with it.
Fluid movement also increases SA of tracheoles, allowing increased area for direct diffusion out.
Why can mechanical ventilation be important in insects?
Increases efficiency of respiration.
Especially important for insects that use a lot of energy flying, as requires lots of O2.
What structures are used for mechanical ventilation in insects?
air sacs (enlarged areas of a trachea that can change in volume)
How do insects mechanically ventilate?
Change in pressure/volume of air sacs
(either muscular pumping movements in thorax and abdomen changing volume of body or compression of air sacs by pumping blood around bodies)
What does an aquatic organism’s oxygen requirements correlate to?
The complexity of its gill structure
What is the operculum?
A moveable gill cover that is reinforced with rays of bone and encloses the gills within an opercular cavity.
It is removed during dissection so the gills are clearly visible.
Name the two parts of the gills ‘gill l_____’ and ‘gill f____’ and describe their functions/ adaptations
gill lamellae= rich blood supply and large SA are main site of gas exchange
gill filaments= finger-like projections occur in large stacks called gill plates. Gill plates had a rich supply of capillaries into which O2 can diffuse. Filaments need a flow of water to keep them apart, exposing large SA for exchange.
Water flow in fish (naming cavities) and What causes ventilation?
Water flows into buccal and pharyngeal cavities, passes across gills to opercular cavity and out to environment through operculum.
Volume changes in the buccal and opercular cavities create pressure that are responsible for ventilation - almost continuous flow of water created.
How many pairs of gills are located within the pharynx of a bony fish?
four pairs