Mass transport Flashcards
Why do large organisms have a transport system based on two criteria?
Low surface are to volume ration means larger organism and small surface area do a transport system is needed to carry ,etsblic products to cells and waste away.
The more activity an animal does the greater the need for a specialised transport system with a pump.
What is a transport system’s purpose?
Takes material from cells to specialist exchange surfaces and from exchange surfaces to cells.
Key features of transport system named
Suitable medium
Form of mass transport that is more rapid than diffusion
A system of tubes/vessels
A mechanism for moving the medium
Why is a suitable medium needed for transport system
Normally a water based liquid as water dissolved substances can be gas medium like air
To carry metabolic products with ease
Why is a a form of mass transport that is more rapid than diffusion needed for transport system
Medium is moved in bulk over large distances = more efficient
Why is a system of tubes and vessels needed for transport system
Contains medium and forms a branching network to distribute to all parts of an organism
Why is a mechanism for moving medium needed for transport system
Creates pressure differences
Animals use muscular contraction
Mammals use intercostal muscles and diaphragm durijg breathing
Plants mechanism for moving medium?
Plants use natural passive processes like the evaporation of water
A mechanism that maintains mass flow movement in one direction are
Valves
Open circulatory system description and what organisms use it
Heart pumps blood through blood vessels into open cavities, which bathe all organs and tissues throughout the body in blood
Insects
Advantages of the open circulatory system
Good for organisms with a slower metabolism (less active) because the absence of blood vessels mean that blood pressure is low so O2 takes longer to reach cells.hence less energy is needed to make energy O2 is needed
Closed circulatory system description and which organisms
Found in larger and more a five animals (all vertebrates)
Not bathing all tissues in blood but is instead transported to all extremities and remains in blood vessels
Mammals also use a closed system
Advantages of a closed circulatory system
Higher blood pressure in larger organisms hence this system is efficient because uses less blood for higher and faster levels of distribution so O2 reaches the extremities faster, which allows faster movement, digestion and removal of waste.
Single closed circulatory system description and organism
Blood travels from the heart to site of blood oxygenation and then to the rest of the body straight away
(Fish=gills)
Double loop closed system description and organism
Mammals, reptiles birds all have a higher metabolic rate and body te party re and need blood quicker
Blood travels in the first loop from the heart to the lungs to be oxygenated then back to the heart.
Then does second loop from the heart to the rest of the body.
Advantages of a double closed loop circulatory system
Quicker and greater pressure as it is returned to the heart so blood has enough pressure to reach all extremities quickly
Describe flow of blood in humans ( no valves needed jus to show flow of blood in double loop).
From vena cava into RA then into RV then from PA to lungs then go PV into LA into LV into aorta and then branches to the rest of the body.
Describe the electrical conduction system and SAN in heart process
A wave of electrical activity spreads out from the sino - atrial node (pacemaker) across the atria. Non - conducting tissue prevents the spread to the ventricles. Wave enters the second group of cells called the atrio ventricular node (AVN ). There is a short delay to allow blood to flow into the ventricles. Then the wave of excitation continued along specialised muscle fibres beteeen the ventricles (Bundle of His) then branches further.
Wave then passes along the purkinje fibres causing the the ventricles to contract from the base upward and then the pressure increases and nodes shut.
NOT NERVES - SPECIALISED HEART CELLS
ECG full form what can be seen what to look out for
Electrocardiograma shows activity of the electrical conduction system (electrical waves) need to/know starts at SAN -> AVN-> bundle of His -> bundle branches -> purkinje -> ventricles
Work out heart rate by going peak to peak and diving sixty by this number
Diastole
Atria full and pressure rises, pressure exceeds that of ventricle so atrioventricular valves open (bi/mi/tri), blood enters ventricle with aid of gravity, both a and v muscles are relaxed, recoil in v muscles causes pressure to reduce so v pressure is less than aorta/PA so semilunar valves shut creating dub
Order of systole and diastole
Diastole (both) (relaxed) then atrial systole then ventricular systole
Diastole vs systole difference
Diastole is relaxed
Systole is contracts
Atrial systole
Atrial walls contract and the recoil of v muscles pushes remaining blood into ventricle - v muscles are always relaxed here
Ventricular systole
Short delay allows ventricle to fill with blood
Both v muscles contract simultaneously which increases blood pressure of ventricle so atrioventricular valves (bi/mi/tri) shut “lub” then presssure in v increases and excess aorta and PA so ASL and PSL open and v muscle contracts to pump blood through so blood flows around the body
Pressure in the heart two main facts
Blood circulation relies on the pressure gradients
Blood will always move down a pressure gradient - from high to low
Diet and obesity causing CVD
High levels of salt raise BP
High levels of saturated fat increase Low Density Lipoproteins (LDL) level hence increase blood cholesterol
Antioxidants reduce risk of heart disease as does non starch polysaccharide/ dietary fibre
High blood pressure genetic predisposition
Can not change this fact can only manage lifestyle factors
Blood cholesterol and CVD
High density lipoproteins (HDL) remove cholesterol from tissues and transport it to to the liver for excretion protect the artieries against heart disease
LDL transport from liver to tissues including the artery walls which get infiltrated and lead to atheroma which leads to heart disease
Why does higher blood pressure increases risk of CVD
Already high pressure in the arteries, the heart must work harder to pump blood into them, hence is more prone to failure
High blood pressure within the arteries mean they are more likely to develop an anyerusm (wearing of the wall) and burst, causing haemorrhage
To resist the higher pressure within them, the walls of the arteries become thicker and may harden, which could restrict blood flow
Arterioles function
Smaller arteries that control blood flow from arteries to capillaries
Capillaries function
Tiny vessels that link arterioles to veins and are small so permeate tissue to distribute metabolic material
Básica structure of blood vessels
Tough fibrous outer layer to resist both internal and external pressure
Muscle layer to contract and control blood flow
Elastic layer to maintain BP by streacthing and recoiling
Endothelium (inner lining (thin)) is smooth to reduce friction and thin to allow easy diffusion
Lumen is a centavo cavity through which blood flows
Fenestrations are
Fenster = window (German)
Windows for exchange of material like WBC in endothelium
Arterioles have similar proportions to arteries but smaller ——— and larger ——— ——— and lower —— . Why?
Smaller in diameter as it slows blood flow in time for exchange
Larger muscle layer and lumen allows for vasoconstriction and vasodilation to control blood flow
Lower pressure than artery so relatively thinner elastic layer as not much recoil needed to control BP
artery basic structure compare to veins Muscle layer Elastic layer Overall thickness Valves
Thicker muscle layer for constriction and dilation as volume of blood need to be controlled to reach tissues
Thicker elastic layer as BP in artery is high and blood needs to reach extremities - this manages pressure surge es from heater because stretches at systole and recoils when hearts relaxes so diastole
Thicker overall than veins because it needs to resist bursting under pressure
No valves as there is high and constant pressure so unlikely back flow
Vein structure compared to artery Muscle layer Elastic layer Overall thickness Valves
Near muscle layer because carries blood away from tissues so vasoconstriction/vasodilation is unnecessary
Thinner elastic layer because low BP in veins so low risk of bursting, hence no recoils action needed
Overall thickness of wall is small because pressure is low so unlikely to burst also allows flattering by=muscles which aids blood flow
Valves at intervals because low pressure means back flow could occurs
How do muscles aid valves in veins to ensure blood only flows to heart
Muscles contract, which compresses veins, which pressurises the blood flow, hence the valve ensures the pressure only directs blood in one direction
Capillary function
To exchange metabolic materials (O2,CO2,C6H12O6) between blood and the cells of the body
Capillary structure
Mostly inner lining layer (endothelium) = extremely thing so short diffusion distance (Fick’s Law)
Numerous and highly branched so large SA for exchange and slows blood flow so there is more time for exchange to occur
Narrow diameter means the tissue can permeated si no cell is far from a capillary = short diffusion distance
Narrow lumen means RBC can just fit - walls are against side of capillary so there is a short diffusion distance as it is close to cell
Fensters = allow WBC to escape to deal with any tissue infections
What is the final journey of metabolic materials made in?
Every cell can’t be served directly by capillary so tissue fluid bathes cells
