chapter 7 and 8 test ( not finished ) Flashcards
why do single celled organisms only use only diffusion to supply themselves with oxygen
large SA:V ratio, low metabolic activity means less CO2 and O2 production and need is lower
what are the characteristic features of effective exchange surfaces
good blood supply, thin layers, increased surface area, ventilation to maintain diffusion gradient
what are important features of the nasal cavity
a large surface area with a good blood supply warms the air
a hairy lining that secretes mucus
moist surfaces
features of mammalian trachea
lined with incomplete rings of cartilage
lined with ciliated epithelium and goblet cells
Bronchus?
small trachea
Bronchioles?
no cartilage rings, walls of smooth muscle which can contract and dilate to control the amount of air reaching the lungs,
Alveoli
tiny air sacs, contain collagen, elastic fibres which allow the alveoli to stretch as air is drawn in, when they return to resting size air is squeezed out, elastic recoil
adaptations of alveoli?
large surface area, thin layer, good blood supply, good ventilation, lung surfactant
inspiration
diaphragm contracts, flattening and lowering, external intercostal muscles contract moving ribs upwards and outwards, volume of thorax increases so pressure is reduced, air is drawn in
expiration
diaphragm relaxes moving it up, external intercostal muscles relax so ribs move down and inwards, alveoli return to normal shape, volume of thorax decreases, air moves out of the lungs
forcible expiration
internal intercostal muscles contract to pull ribs down hard and fast
what can you use to measure different aspects of lung volume
spirometer
tidal volume
volume that moves in and out of the lungs with each resting breath
vital capacity
volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath
inspiratory reserve volume
maximum volume of air you can breathe in over and above a normal inhalation
expiratory reserve volume
extra amount of air you can force out of your lungs over and above the normal tidal volume of air you breathe out
residual volume
volume of air that is left in your lungs when you have exhaled as hard as possible
total lung capacity
sum of the vital capacity and the residual volume
how to calculate ventilation rate
tidal volume x breathing rate per minute
what are spiracles
small openings in the thorax and abdomen of an insect where air enters and leaves the system. Can be open an shut by spiracle sphincters to control water loss
insect tracheae
carry air into the body, lined with spirals of chitin which keeps them open
insect tracheoles
greatly elongated cell with no chitin so are permeable to gases
how do some bugs increase the level of gaseous exchange to supply extra oxygen needed
mechanical ventilation of the tracheal system, collapsible enlarges tracheae or air sacs
adaptations of gills
large surface area, good blood supply, thin layers and there is a protective operculum,
how does a fish’s mouth aid in ventilation of the gills
when opened the floor of the buccal cavity is lowered which decreases volume of buccal cavity, at the same time the opercular valve is shut and the opercular cavity expands which lowers pressure in the opercular cavity, as mouth moves up it increases pressure moving the water over the gills
what are the extra special adaptations of gills
tips of adjacent gill filaments overlap which slows down movement of water which allows for more time for gaseous exchange, water can move in countercurrents which creates a steeper concentration gradient
why are specialised transport systems needed in some organisms
high demands, small SA:V ratio, hormones and enzymes are needed in a different place to where they were made, food nutrients needs to be transported all around the body, waste products need to be removed
where are open circulatory systems found
insects and some molluscs
where single closed circulatory systems found
fish and annelid worms
where are double closed circulatory systems found
mammals
gimme some important info on arteries
the walls contain elastic fibres, smooth muscle and collagen, elastic fibres allow them to withstand the force and volume of blood and recoil to even out surges, smooth muscle so blood flows easily over it, small lumen to maintain high blood pressure
tell me about some arterioles
link arteries and capillaries, more smooth muscle and less elastin, can contract and dilate to control flow of blood, smooth muscle allows for vasoconstriction and vasodilation
TELL ME BOUT DEM capillaries
small lumen to fit in between all the cells, capillary walls are one cell thick, slow movement of blood for more time for diffusion
veins, gimme that sweet info
valves to prevent backflow, movement of muscles act as a pump
functions of blood?
carry round CO and O2, digested food from small intestine, nitrogenous waste products to excretory organs, hormones, food molecules from storage compounds, platelets, cells and antibodies, maintains steady body temperature, minimises pH changes
tissue fluid?
facilitates exchange, helps bring oxygen and nutrients to cells and remove waste products
Lymph
maintains fluid levels by removing fluid that leaks out of our blood vessels
