Transport In Animals Flashcards
Need for specialised exchange surfaces
- metabolic activity is higher than single felled organisms
- distance between the cells and where oxygen is needed and the supply of oxygen is too far for effective diffusion
Sa:Vol ratio is too small for efficient gas exchange
Specialised exchange surfaces properties
- increased sa
- thin layers - quick diffusion
- good blood supply
- ventilation to maintain diffusion gradient
Human gaseous exchange system
Nasal cavity
Trachea
Bronchus
Bronchioles
Alveoli
Nasal cavity
Good blood supply warms air to body temp
Hairy mucus lined to trap bacteria
Moist reduces evaporation
Trachea
Wide tube of C shaped cartilage (incomplete for food to move)
Goblet cells secrete mucus trapping dust/unwanted shit
Ciliated Epithelium- waft away mucus and dust etc from lungs
Bronchus
Trachea divides to form bronchi
Similar structure to trachea but smaller
Bronchioles
No cartilage
Walls contain smooth muscle which constricts and dilated controlling air flow
Thin flattened epithelium where some exchange can occur
Alveoli
Tiny air sacs where main exchange occurs
Contain flattened epithelial cells with some collagen and elastic fibres to allow elastic recoil depending on air drawn in/out
Alveoli adaptations
- large sa :vol ratio
- thin layers
-good blood supply - good ventilation- breathing in and out
- lung surfactant makes it possible for alveoli to remain inflated
Inspiration
-diaphragm contracts flattens and lowers
- ex intercostal muscles contract - ribs up and out
- thorax pressure reduced lower pressure
Expiration
Diaphragm relax
Ex intercostal muscles relax ribs down+ in
Alveoli elastic fibres relax
Thorax pressure increase moves air out
Forced- in intercostal muscles contract forcing diaphragm up
Measuring lung capacity
Peak flow meter
Spirometer
Vilatographs
Tidal vol
Vol air and out resting
Vital capacity
Vol air strongest inhale and exhale
Inspiratory and expiratory reserve
Max ins/exp reserve- tidal
Residual volume
Air left in lungs after strongest exhalation
Ventilation rate
Tidal vol x breathing rate
Why do insects have an exchange system
Have a tough exoskeleton so no exchange occurs on surface so require specialised exchange system
Spiracles
Air enter and leaves
Water is also lost here
Minimised by sphincters
Located in thorax and abdomen
Tracheae
Largest tubes
Leading away from spiracles
Lined w chitin - impermeable and strong
Lead to tracheoles
Tracheoles
No chitin so permeable for gas exchange
Tracheol fluid at ends of tracheoles which limits diffusion
V large sa
Tracheal fluid
Seeps into tracheoles at rest
Muscles draw up fluid when active
Lowers pressure in tracheoles and incr sa for direct gas exchange
Larger insect adaptations
Pump using thorax / abdomen incr decr pressure forcing air in and out
Air sac reserves
Exchange in fish
Cannot diffuse through scales water has low O2 affinity
Oxygen rich O2 moves via mouth and over gills exchanging O2 and CO2
Fish structural gas exchange system
Gills - maintain a unidirectional flow of water and are supported by bony hill arches
Gill filaments extend from the arch large stacks exposing the large SA
Gill lamellae- rich blood supply large sa main site for gas exchange
Counter current flow
Direction of water opposite to blood flow
Maintain steep conc gradient for efficient gas exchange
Gas exchange system in fish
- Fish opens mouth and floor of buccal cavity drops increasing vol for H2O
- Operculum shuts increasing volume of operculum cavity
- Buccal floor lifts incr pressure and water flows into operc. Cavity over gills
- Fish closes mouth and operculum opens allowing H2O to be forced out operculum
circulatory systems requirements
Liquid transport medium
Vessels that carry medium
Pumping mechanism
Mass transport system
When substance transported in mass of fluid w mechanism moving fluid around body
Open circulatory system
Very few vessels
Straight from heart to body cavity of the animal - haemocel
Haemolymph in insects carries nutrients and nitrogenous waste
Closed circulatory system
Blood is enclosed in vessels and does not come into contact with the cells of the body
Heart pumps blood around the body under pressure returning to the heart
Single circulatory system
Blood travels through heart once for each complete circulation of the body
2 sets of capillaries - exchange O2 and Co2 & supply cells
Blood returns to the heart slowly
Double circulatory system
Travels twice through the heart for each circuit of the body
Blood pumped from heart to lungs to pick oxygen and unload CO2
Pump again to the body
High pressure+ blood flow
Arteries
Elastic fibres to withstand blood surges
Smooth endothelial layer
Smooth muscle constrict and dilate vessel
Collagen maintain elastic stretch
Arterioles
More smooth muscle
Less elastin little pulse surge
Capillaries
Link arterioles to venues
1 rbc at a time slow for max diffusion
Substances are exchanged through gaps in the wall tissue fluid
Large Sa / thin for diffusion
Veins and venues
Low pressure
Valves prevent blood flow
Lots of collagen little elastic fibres
Wide lumen
Smooth muscle to maintain blood flow
Low pressure blood adaptations
One way valves at intervals
Big veins run between big active muscles which contract often pushing blood back to the heart
Breathing movements act as a pump altering pressure
Composition of blood
55% plasma
RBCs WBCs and platelets
Composition of plasma
Glucose
Amino acids
Hormones
Albumin - osmotic potential protein
Fibrinogen - clotting protein
Globulins - immune system protein
Functions of the blood
Transports O2/Co2 /digested food from s intest. / nitrogenous waste / hormones/ platelets etc
Acts as a buffer minimising pH changes
Tissue fluid
Substance that passes through fenestrations of the capillaries into tissues
Oncontic pressure
Albumin gives blood a low water potential - water moves into blood by osmosis
Hydrostatic pressure
Pressure from blood surge every time heart contracts - tissue fluid is forced out 4.6kPa
This falls as move along the capillary 2.3kPa and the oncotic pressure remains so water moves back into the capillary via osmosis
Lymph
Tissue fluid remains drained into lymph capillaries
Containing valves to prevent back flow
Lymph nodes are along the capillaries which contain lymphocytes to intercept debri
Return to blood plasma
Haemoglobin
Red pigment that carries oxygen
Globular conjugated protein with a haem prosthetic group
300 million per RBC
O2 binds loosely
Carrying oxygen
O2 binds w haemoglobin this causes Hb to change shape making it easier for the second to bind - positive cooperativity
Free O2 in RBC is low so steep conc gradient maintained until Hb is saturated
Unloading oxygen
Once first oxygen breaks away Hb molecules change shape so it is easier to remove the O2
Oxygen dissociation curve
S shaped when one O2 binds changes Hb shape for it to be easier to bind
a) low pO2 few haem groups attached to O2 so Hb doesn’t carry much
b) more Hb attached to O2 easier to bind
c) Hb saturated at v high pO2 as all haem groups bound
Effect of CO2
Higher pCO2 Hb gives up oxygen more easier
Important in active tissue exchange and in the lungs
Transporting CO2
5% in plasma
10-20% as carb amino haemoglobin (CO2 binds to haem group)
75-85% into HCO3- ions
CO2 as hydrogen carbonate
CO2 react with H2O in RBC forming H2CO3
Dissociates into H+ and HCO3-
HCO3- moves out RBCs and Cl- move in
H+ removed by buffers
HCO3- and H+ reversed forming CO2 and H2O at the lungs
Right side of heart
Deoxygenated blood from body to heart to lungs
Vena cava into the right atrium
Right ventricle into pulmonary artery
Right atrium hold the SAN
Left side of heart
Oxygenated blood from lungs to heart to body
Pulmonary vein from lungs to left atrium
Left ventricle to aorta to the body
Heart function cycle
- Atrial systole/ ventricular diastole - atrial contract forcing blood through atrioventricular valve (tricuspid/bicuspid)
- Atrial diastole/ ventricular systole - ventricle pressure increases and forces blood through semi lunar valve
- Atrial/ ventricular diastole - atrium fills with blood high pressure some passes through into ventricles passively
Lub dub noise
Lub= blood against av valve from ventricular systole
Dub= blood against sl valve from ventricular diastole
Electrical excitation of the heart
Cardiac muscle is myogenic- own intrinsic rhythm
Sino atrial node causes atria to contract
Insulating tissue between atria and ventricles to prevent ventricles contracting
Atrioventricular nodes stimulate bundle of his stimulating purkyn fibres triggering contraction of ventricles
ECGs
Small start wave- atrial systole
Double opposite peak- ventri. systole
B-road peak - ventricular diastole
Abnormalities of heart rhythm
Tachycardia- rapid >100bpm
Bradycardia- slow >60bpm
Ectopic- extra beat
Atrial fibrillation- random (rapid impulse from atria only some impulse passed onto ventricles)
