organisms exchange substances with the environment Flashcards
What is the cell membrane?
exchange surface
surface area to volume ratio: formula
surface area/ volume
what is a problem that insects face
loss of water vapour can be released by fluid
prevent - SPHINCTER
insects gas exchange system structure
exoskeleton - but SPIRACPES allow gas to enter/ escape,
trachea - CHITIN to prevent collapsing 1mm
TRACHEOLES - large amounts of spiracles, large SA : V, rapid rate of aerobic respiration
1um, tubes have NARROW DIAMETER - short diffusion PATHWAY
tracheal fluid
aerobic respiration causes lactic acid, lowers water potential, water from tracheal fluid moves into cells, this uncovers more tracheal surface available
why is it a passive process in insects
O2 from air with a high external o2 concentration moves to low con in the sphincter
insects
have a high oxygen demand (active)
oxygen directly reaches cells
counter- current exchange system in fish
flow of blood is perpendicular to the flood of blood
There is never an equilibrium between concentration gradients because oxygen-rich blood is taken away and new blood with no oxygen will enter through capillaries
adaptation of lamellae for efficient gas exchange
- extensive network of capillaries high surface area for o2 intake
- many lamellae = high SA: V
- thin membranes = short diffusion pathway - quickly
- once o2 enters blood it is carried away
fishes exchange network
operculum
|> Operculum cavity
|> gills
gills
|> gill filaments
|>LAMELLAE
issue of fish and their environment
water concentration is lower in water than air - they must adapt to take in that 02 well
mammals gas exchange
mammals have a high rate of aerobic respiration (high O2 demand)
nose (NASAL CAVITY), have hair - traps pathogens, warms + moistens air
TRACHEA is made up of cartilage, goblet cells, and ciliated epithelial cells. MUCUS created + cilia waft mucus down to throat where it is swallowed + digested
BRONCHIS - cartilage. goblet, ciliated epithelial cells
BRONCHIOLES - cartilage + smooth muscle - can relax to expand for more air
ALVEOLI - sites of GAS EXCHANGE
extensive capillary network rapidly carried away - steep concentration gradient
O2 dissolves on moisture of alveolar wall
1 cell thick - short diffusion distance
process of inhalation in mammals
external muscles contract - pulls ribs out + up diaphragm contracts + flattens
increase volume of THORAX
LOW pressure in lungs causes air to move down pressure gradient to LUNGS
air moves to alveoli - where elastic fibres STRETCH)
what type of process is inhalation and exhalation
inhalation - active due to energy needed for the contraction of external external intercostal muscle
Exhalation - passive - involves the relaxing of muscles
the process of exhalation in mammals
external intercostal muscles relax
diaphragm relaxes
volume of thorax decreases lungs have higher pressure so moves down pressure gradient
moves out of lungs, elastic fibrers relax - ELASTIC RECOIL
why are the intercostal muscles described as ANTIGNSTIC
in exercise, breathing out is not passive, it requires the internal intercostal muscles to contract
as internal intercostal muscles contract to pull ribs down + inwards forcing more air out and external intercostal muscles relax
when one relaxes, the other contracts
what is a single circulatory system, what is the problem with this
when the blood only passes the heart ONCE around the
initially, blood pressure is high from the heart but as it passes through the capillaries, it is lowww - slows down O2 delivery to the blood
double circulatory system
blood passes the heart twice around circulatory system
lung - heart (pump) - body
body - heart ( pump) - lungs
what is the relaxing and dilation of the smooth muscle in arteriole
contraction = VASOCONSTRICTION
relaxing = VASODILATION ( for when organ needs more oxygen)
role of parts of artery + arteriole
collagen-rich outer layer - STRUCTURAL to strengthen the wall against the high pressure of blood
Smooth muscle - controlling blood by contracting or dilating
elastin protein - blood surge after heart pump stretches and when it leaves it recoils
structural differences in arteries and arterioles
arterioles have thinner collagen + elastin protein due to lower pressure in blood
BUT
have thicker smooth muscle to control the blood flow for the capillaries
