2(f, g) Flashcards
Function of Trachea?
Airway leading from throat to lungs.
Function of Ribs?
Create the ribcage which move during respiration but also protect heart and lungs from major damage.
Function of Intercostal muscles?
Muscles which when contracted pull ribcage up and out creating space for air in lungs.
Function of Bronchi?
Airway leading from trachea into each lung.
Function of Alveoli?
Small air sacs adapted for gas exchange key part of lung.
Function of Diaphragm?
Can contract during inspiration to become flat.
Function of Pleural membranes?
Keep the thorax airtight and reduce friction during ventilation.
Function of Goblet cells in trachea and bronchi?
Secrete mucus which trap pathogens (disease causing microorganisms, e.g. bacteria) and dirt (e.g. dust) in the lungs.
Function of Ciliated cells in trachea and bronchi?
Ciliated cells have tiny hair-like projections called cilia, which beat rhythmically to waft the mucus up the bronchi and trachea to the throat where it is swallowed.
What is the use of cartilage in the bronchi and trachea?
To hold airways open and prevent collapse when the air pressure inside is low during inspiration.
What is the use of the smooth muscle in the trachea, bronchi and bronchioles?
To constrict the airways to control the flow of air to the alveoli; this may be important of there are harmful substances in the air by contracting.
What is the use of the elastic tissue in the trachea, bronchi, bronchioles and alveoli?
Recoil to allow the airways to spring back to their normal size after airway constriction so the airways dilate (widen); also allow the alveoli to spring back to normal shape during expiration.
State 3 adaptations of the Alveoli for gas exchange.(3)
Sac shaped = increased surface area for faster diffusion.
Thin wall = shorter distance for diffusion.
Capillaries wrapped around alveoli = moving blood creates steep concentration gradient for faster diffusion.
Cause of lung cancer?
Carcinogens in the tar of tobacco smoke can enter cells and cause them to divide out of control causing tumours.
Cause of chronic bronchitis?
Tar in tobacco smoke causes goblet cells to secrete more mucus, which causes the cilia to be paralysed – this means any pathogens cannot be wafted out of the lungs and can cause infection.
Cause of emphysema?
The bodys white blood cells attempt to kill these pathogens but in doing so damage the elastic fibres in the walls of the alveoli – the alveoli burst which reduces the surface area available for gas exchange.
State the effects of tar on the body?(3)
Tar can include carcinogens as well as other chemicals.
Lines airways and alveoli with tar.
Paralyses cilia cells.
May cause smooth muscle in airways to contract restricting air flow.
State the effects of nicotine on the body?(3)
Very addictive and stimulates release of adrenaline.
Reduces diameter of arterioles.
Increases heart rate and blood pressure.
Increases risk of blood clot and reduces oxygen supply to hands and feet.
State the effects of carbon monoxide on the body?(2)
Diffuses across alveoli where it combines with haemoglobin to form carboxyhemoglobin because carbon monoxide outcompetes with oxygen because it has a 200x higher affinity than oxygen with haemoglobin.
When guard cells fill with water and become turgid…
The stomata open to allow gases in and out of the plant.
When guard cells lose water and become flaccid…
The stomata close.
State three ways the structure of the leaf is adapted for photosynthesis(externally).(3)
1 Large surface area to absorb sunlight
2 Green chlorophyll to absorb light
3 Supported by stalk that allows leaf to be angled towards light
State six ways the structure of the leaf is adapted for photosynthesis(internally).(6)
1 Upper epidermis is transparent to allow light to pass trough.
2 Waxy cuticle to prevent water loss by evaporation and entry of pathogens.
3 Lower epidermis has stomata to allow CO2 to diffuse into the leaf.
4 Palisade mesophyll (mesophyll = middle of leaf) has elongated cells packed with chloroplasts close to the source of light.
5 Palisade cells have large vacuoles which push chloroplasts to the edge of cell.
6 Good supply of water from xylem to mesophyll.
Explain two ways how the structure of the leaf is adapted for gas exchange?(2)
1 Leaf is thin therefore diffusion distance is fairly short
2 Stomata and air spaces in the spongy mesophyll contribute towards efficient gas exchange(rate of diffusion greater in air than water)