Transport in animals. Flashcards
(16 cards)
(a) What is the need for transport systems in multicellular animals?
1 - Multicellular organisms are larger, so the diffusion distance across their surface would be too large.
2 - Multicellular organisms have a higher metabolic rate.
3 - Multicellular organisms need to supply nutrients and oxygen rapidly to a larger number of active cells.
(b) What are the different types of circulatory systems? (Fish)
1 - The heart pumps blood to the gills to pick up oxygen.
2 - Blood flows directly from the gills to the rest of body to deliver oxygen.
This is single circulatory system.
(b) What are the different types of circulatory systems?
(Mammals)
1 - The right side of the heart pumps deoxygenated blood to the lungs to pick up oxygen.
2 - The left side of the heart pumps oxygenated blood to the rest of the body, which gives an extra push to deliver this blood more quickly to distant body tissues
(b) What are the different types of circulatory systems?
(open)
Their blood flows freely through the body cavity; Blood returns to heart through valves; Blood doesn’t just transport oxygen.
(b) What are the different types of circulatory systems?(closed)
Their blood is enclosed in vessels; Arteries generally distribute oxygenated blood; Veins generally return deoxygenated blood to heart.
(c) the structure and functions of arteries?
Carry blood away from the heart.
Collagen - Provides strength to prevent the vessel from bursting and to maintain vessel shape;Elastic fibres - Contain elastin that lets them stretch and recoil to minimise changes in pressure;Thick smooth muscle layer - Contracts/relaxes to constrict/dilate the lumen and control blood flow.
(c) the structure and functions of arterioles?
Arterioles are smaller than arteries, but with a comparatively larger lumen. Their walls have more smooth muscle and less elastin as they do not need to withstand such high pressures.
(c) the structure and functions of venules and veins?
Venules - Carry blood from capillaries into veins; Veins - Return blood to the heart. Collagen - Provides strength to prevent the vessel from bursting and maintain vessel shape; Little smooth muscle and elastic fibre Not much is needed due to low blood pressure, and thinner walls allow veins to be easily compressed, aiding the flow of blood; Valves - Pocket valves shut to prevent the backflow of blood when veins are squeezed by surrounding skeletal muscle.
(c) the structure and functions of Capillaries?
Capillaries - Site of diffusion between blood and body tissues. Lumen is very narrow - This allows red blood cells to be close to body cells; Walls are thin - Substances can be exchanged across a short distance by diffusion; Highly branched - This provides a large surface area for diffusion.
(d) What is the formation of tissue fluid from plasma?
At the arteriole end of capillaries:
1- A high hydrostatic pressure, exerted by the force of the heart pumping, forces fluid out of capillaries.
2- This forms tissue fluid surrounding body cells.
At the venule end of capillaries:
1- The hydrostatic pressure is lower
2- Proteins in blood exert a high oncotic pressure, a type of osmotic pressure, in capillaries.
3- The water potential is lower in capillaries than in tissue fluid due to fluid loss.
4- Some tissue fluid moves back into capillaries by osmosis.
The formation and transport of lymph.
It is formed and transported around the body as follows:
1- Some tissue fluid doesn’t re-enter capillaries from tissue fluid.
2- This fluid instead drains into lymph vessels (lymph capillaries) forming lymph.
3- Lymph is transported through lymph vessels by muscle contractions.
4- Lymph is passed through lymph nodes to filter pathogens.
(f) What is the cardiac cycle?
(Stage 1)
Stage 1 - Atrial systole
The ventricles relax, and the atria contract; This increases the atrial pressure; The
atrioventricular valves open; Blood flows into the ventricles.
(f) What is the cardiac cycle?
(Stage 2)
The ventricles contract, and the atria relax; The ventricular pressure increases; The semi-lunar valves open, and the atrioventricular valves close; Blood flows into the arteries.
(f) What is the cardiac cycle?
(stage 3)
The ventricles and atria relax; The semi-lunar valves close; Blood flows passively into the atria.
(g) How heart action is initiated and coordinated?
This wave travels through the following structures in this order:
1 -Sinoatrial node (SAN) - Initiates the heart beat by stimulating the atria to contract.
2 -A layer of collagen fibres - Prevents direct electrical flow from atria to ventricles.
3 -Atrioventricular node (AVN) - Picks up the electrical activity from the SAN and imposes a slight delay.
4 -Bundle of His - Receives electrical activity from the AVN and conducts the wave of excitation to the apex (base) of the heart.
5 - Purkyne fibres - These branch off the bundle of His, causing the right and left ventricles to contract from the bottom upwards.
(h) What is the use and interpretation of electrocardiogram
(ECG) traces?
An ECG shows the various stages of the cardiac cycle:
P wave - Atrial systole
QRS - Ventricular systole
T wave - Diastole
ECGs help diagnose abnormalities like:
1 - Tachycardia - This is an abnormally rapid heart rate.
2 - Bradycardia - This is an abnormally slow heart rate.
3 - Ectopic heartbeats - This is extra heartbeats out of the normal rhythm.
4 - Atrial fibrillation - This is the abnormally rapid and ineffective contraction of the atria.
