AS COMP 2 Flashcards
(80 cards)
what are the 4 features for gas exchange?
- large surface area
- thin walls for short diffusion path
- steep concentration gradient
- permeable
What happens when carbon dioxide can’t be removed fast enough?
Build up a high concentration causing cytoplasm to become acidic for enzymes to function
What are earthworms 4 characteristics
- skin is respiratory surface
- haemoglobin in blood, low metabolic rate
- cylindrical so sa:vol is smaller
- co2 diffuses out down concentration gradient
3 Characteristics of amphibians
- skin is moist and permeable
- well developed capillary network
- gas exchange in skin and lungs
Characteristic of reptile
Lung has a complex internal structure, increase surface area
Characteristic of bird
Large volume of oxygen for flight as requires more energy
6 characteristics of bony fish
High surface area of filimants
Short diffusion path
Countercurrent flow - steel gradient
Rich blood supply
Ventilation system
One way flow
Process of uptake of water by ventilation
Mouth opens
Operculum closes
Floor of mouth lowers
Volume inside mouth increases and pressure decreases
Water flows in as external pressure is higher than inside mouth
Process of removal of water using ventilation
Mouth closes
Operculum opens
Floor of mouth rises
Volume inside mouth decreases and pressure increases
Water flows out as pressure is higher inside
What is countercurrent flow?
Blood moves in one direction and water moves opposite
What happens if we increase distance of lamella ?
Concentration of oxygen increases and water decreases
Define negative pressure
Pressure inside lungs must be below atmospheric pressure for air to come in
Process of inspiration/inhalation
- external intercostal muscles contract
- ribs pulled upwards and outwards
- same time diaphragm contracts and flattens
- outer pleural membrane is pulled up and out with ribs and lower part is pulled with diaphragm, inner membrane follows and lung expands increasing volume inside alveoli
- reduces pressure in lungs
- atmospheric pressure is greater than pressure in lungs so air is forced out
Process if expiration/exhalation
- external intercostal muscles relax
- ribs are pulled downwards and inwards
- diaphragm muscles relax and domes upwards
- pleural membrane moves down and in with ribs and lower parts move up with diaphragm, volume inside lung decrease decreasing volume in alveoli
- air pressure greater than atmospheric, air forced out
What is surfactant in alveoli made of and its use
Made of secretions containing phospholipids and proteins
Used for preventing collapse in exhalation as it has low surface tension
4 Characteristics of gas exchange in alveolus
Large surface area
Gasses dissolve in surfactant moisture lining
Walls made of squamous epithelium, one cell thick for short diffusion path
Extensive capillary network to maintain diffusion gradient
Stages of gas exchange in alveolus
- deoxygenated blood enters the capillary surrounding the alveoli
- oxygen diffuses out of the air in the alveoli into red blood cells in capillary
- carbon dioxide diffuse out of the plasma in the capillary into the air in the alveoli from where it is exhaled
What happens to guard cells during the day?
Open and become turgid and swell
What happens to guard cells during the night
Close and become flaccid
Define open circulatory system
Blood does not move around the body in blood vessels
Define closed circulatory system
Blood does move in blood vessels
What are 2 types of close system
Single circulation
Double circulation
What is single circulation
Blood moves through the heart once in its passage around the body
Define double circulation
Blood passes through heart twice in its passage around the body