3.1.2 Transport in Animals Flashcards
How are erthrocytes specialised?
- Biconcave shape - increases their SA:V ratio
- No nucleus - more space to hold more haemoglobin so they can carry more O2
- Small size, flexible so can fit through capillaries
How are neutrophils specialised?
- Multi-lobed nucleus - can squeeze through small vessels easily
- Cytoplasm contains many lysosomes with enzymes to attack pathogens
How are sperm cells specialised?
- Acrosome releases digestive enzymes to break through the egg membrane
- Flagellum allows for quick movement to the egg
- Contain many mitochondria to have the energy to swim
How are palisade mesophyll cells specialised?
- Contain chloroplasts for photosynthesis - can move through cytoplasm to absorb more light
- Rectangular shaped cells - package closely together
- Thin cell walls - increases rate of diffusion
- Large vacuole to maintain turgor pressure
How are root hair cells specialised?
- Microscopic size - penetrate easily between soil particles
- Large SA:V ratio
- Thin surface layer
- Concentration of solutes maintains the concentration gradient for water uptake
How are guard cells specialised?
Can change shape to control the amount of water that leaves and the gases that enter. Become turgid with water and open, become flaccid (lose turgor pressure) due to lack of water so return to regular closed shape. Inner wall of the cell is less flexible than outer wall, so it becomes bean shaped.
How is the squamous epithelium specialised?
Very thin - only one cell thick
How is the ciliated epithelium specialised?
Hair like structures (cilia) move in rhythmic manner. Goblet cells release mucus to trap any unwanted particles
How is the cartilage specialised?
Contains elastin and collagen - allows for flexibility and structural strength
Why do organisms need a circulatory system?
- SA:V ratio to remove/absorb substances via diffusion (large diffusion distance)
- Metabolic activity too high to rely on diffusion
- Products require elsewhere to where they’re made
- Need to remove waste products
- Need to obtain amino acids, glucose, oxygen, water etc from environment
What features affect the efficiency of an exchange system?
- Surface Area
- Diffusion distance
- Concentration gradient
How do the following factors contribute to an efficient exchange system: large SA, thin layer and good blood supply?
Large SA: increases rate of diffusion
Thin layer: reduces diffusion distance
Good blood supply: maintains concentration gradient
State some adaptations of the lungs
- Many alveoli - together give high SA
- Large network of capillaries surrounding alveoli - higher SA, increased exchange
- Thin alveoli epithelium and capillaries one cell thick - short diffusion distance
- Alveolar and capillary walls are close together
- Ventilation maintains high concentration gradient
- Ciliated epithelial cells and goblet cells clear airways to alveoli (present in bronchioles)
- Constant blood supply - maintains high concentration gradient
Describe the structure and function of the trachea
Structure: Lined with goblet cells and ciliated epithelia, made up of incomplete rings of cartilage and smooth muscle (provides strength and support to keep open)
Function: Smooth muscle can contract to decrease diameter - propels air upwards from lungs (helps when coughing)
Describe the structure and function of the bronchi
Structure: made up of cartilage and smooth muscle, lined with goblet cells and ciliated epithelia
Function: Provide a pathway for O2 to enter and CO2 to leave the lungs. Smooth muscle relaxes to increase diameter to allow more air to flow into the lungs.
Describe the structure and function of the bronchioles
Structure: No cartilage, walls consist of smooth muscle, lined with goblet cells and ciliated epithelia. Inhaled air supports shape - smooth muscle contracts, bronchioles constrict, smooth muscle relaxes, bronchioles dilate
Function: Ensure each alveoli is filled with air
Describe the structure and function of the alveoli
Structure: Squamous epithelial cells make up wall, also consist of collagen and elastin fibres - allow stretch to draw in and return to resting to release air (elastic recoil). Inner surface coated in thin layer solution of water, salts and lung surfactant - remains inflated, decreases surface tension so inflation is easier
Function: exchange of gases with blood - supply oxygen to blood and remove carbon dioxide
Describe the mechanism of ventilation
Inspiration: Diaphragm contracts, moves downwards. Intercostal muscles contract - ribs up and out. Volume of thorax/lungs increases, pressure decreases below atmospheric pressure
Expiration: Diaphragm relaxes, domes upwards. Intercostal muscles relax - ribs down and in. Volume decreases, pressure increases above atmospheric pressure
What happens to facilitate forcibly exhaling?
Internal intercostal muscles contract, pulling ribs down fast and abdominal muscles contract to force diaphragm up
Define vital capacity
Maximum amount of air that can be breathed out after the maximum inhalation - sum of inspiratory and expiratory reserve volumes, and tidal volume.
Define tidal volume
Volume of air breathed in and out in a normal breath, usually 15% of the vital capacity
Define inspiratory reserve volume
Maximum volume of air breathed in above normal
Define expiratory reserve volume
Maximum volume of air breathed out above normal
How do you calculate ventilation rate?
Tidal volume x breathing rate (min)
What are the methods of measuring lung capacity?
- Spirometer - breathe into airtight chamber filled with oxygen, soda lime removes CO2, trace recorded on revolving drum
- Peak flow meter - measures rate of air expulsion
- Vitalographs - peak flow meter, but graph produced of rate of expulsion
Describe the mechanism of ventilation in insects
Mechanical ventilation - muscular pumping of thorax/abdomen controls collapsible tracheae (increase/decrease air through system). Can close some spiracles to retain water. Tracheal fluid at end of tracheoles
What is the purpose of the tracheal fluid in insects?
When resting, bathes tissues to reduce water loss through the tracheae (lowers water potential gradient). When active, fluid diffuses into muscle cells to allow greater gas exchange (would be a barrier to O2 diffusion)
Describe the mechanism of ventilation in fish
Inspiration: open mouth, buccal cavity lowers, opercular cavity increases volume, opercular valve closes
Expiration: close mouth, buccal cavity moves upwards, opercular cavity decreases volume, opercular valve opens