B3.2 Transport Flashcards
function of arteries
carry pulses of high-pressure blood away from the heart to every organ of the body
function of veins
carry a stream of low-pressure blood from the organs back to the heart after it has passed through a capillary bed
in a micrograph what can be shown with a grainy appearance?
clotted blood-in both arteries and veins
adaptations of arteries
thicker wall, narrower lumen, circular in section, inner surface corrugated, fibres visible in the wall
adaptations of veins
thinner wall, wider lumen, circular/flattened, inner surface smooth, no or few fibres visible, outer coat is thin bc theres no danger of veins bursting
why do arteries have the structure that they do?
because they receive blood directly from the heart and the blood is under high pressure=lined with a thick layer of smooth muscle and elastic fibres, and so have small lumen
why do veins have the structure that they do?
receive low pressure blood from capillary beds=relatively thin walls and large lumen to carry the slow-moving blood, the thin walls are also compressed by surrounding muscles
what happens to the blood when it goes through the capillary beds?
blood loses a great deal of pressure and velocity
adaptations of capillaries
large SA due to branching and narrow diameters, thin walls one cell thick, fenestrations in some capillaries where exchange needs to be rapid eg in kidneys at site of filtration
what is tissue fluid?
the solution that bathes all cells
what is pressure filtration?
release of tissue fluid at the arteriole end of a capillary bed
what is tissue fluid formed by?
pressure filtration of plasma in capillaries
what components of the blood can’t leave the capillaries?
RBCs and large proteins, but WBCs are highly flexible squeeze through
what do body cells need and need to get rid of
Need: oxygen, glucose, mineral ions
Get rid: CO2 and urea
adaptations of the cardiac muscle
highly vascular tissue, muscle is thick in the ventricles, muscle making up the wall of the left ventricle is the thickest because it pumps blood out to entire body
adaptations of a pacemaker
called sinoatrial node, it’s an area of specialised cells in the right atrium which generate electrical impulse to start each heartbeat
adaptations for atria
thin muscular chambers designed to receive low pressure blood from the capillaries of the lungs or body tissues by way of large veins entering the heart, atria sends blood to ventricles
adaptations of ventricles
thick muscular chambers that pump blood out under pressure to lungs or body tissues
adaptations of atrioventricular valves
valves located between atria and ventricles that close each heart cycle to prevent backflow of blood into the atria
adaptations of semilunar valves
close after the surge of blood into the pulmonary artery or aorta to prevent backflow of blood into the ventricles
adaptations of the septum
a wall of muscular and fibrous tissue that separates the right side of the heart from the left side
adaptations of coronary vessels
blood vessels that provide oxygenated blood to the heart muslce
explain the single circulatory system of a fish
only 1 ventricle which pumps deoxygenated blood to the gills; blood is pumped at high pressure through gills; surrounding water provides support and prevents capillaries bursting; after flowing through gills blood is oxygenated so has enough pressure to flow directly to another organ; blood becomes deoxygenated and pressure falls; returns to heart to be pumped to gills
what does systole mean?
contraction
