Mass Transport in Animals Flashcards
why is the circulatory system knows as a double system
the blood passes through the heart twice in one circuit
what is the function of the vena cava
carries blood from body to heart
what is the function of the pulmonary artery
carries blood from the heart to the lungs
what is the function of the pulmonary vein
carries blood from the lungs to the heart
what is the function of the aorta
carries blood from the heart to the body
what is the function of the renal artery
carries blood from the body to the kidneys
what is the function of the renal vein
carries blood from the kidneys to the vena cava
the right side of the heart receives …….. blood
deoxygenated
the left side of the heart receives …… blood
oxygenated
the right side of the heart receives blood by the …….
vena cava
the left side of the heart receives blood by the ……
pulmonary vein
what is the difference between the ventricles and the atria and what does this allow
the ventricles have thicker muscular walls which allows them to generate high pressure to pump blood out of the heart
why do the atria not need as thick muscular walls as the ventricles
the atria just need to pump blood a short distance to the ventricles
true or false
the right ventricle of the heart has thicker muscular walls
false
the left ventricle has thicker muscular walls
explain why the left ventricle has thicker muscular walls than the right side
because the left ventricle has to pump blood all around the body whereas the right pumps blood to the lungs
what is the role of valves
prevent backflow of blood
heart valves open based on ……
the pressure of the heart chambers
what are the 2 valves and what do they do
- atrioventricular (AV) - link the atria to the ventricles
- semilunar (SL) - link the pulmonary artery and aorta to the ventricles
explain the process that leads to blood moving from the atrium into the ventricles
- the ventricles relax and have a low pressure
- the atria contract, causing the volume in the chambers to decrease and the pressure to increase
- the AV valve opens and blood enters the ventricles down a pressure gradient
explain the process that leads to blood moving from the ventricles into the aorta and pulmonary vein
- atria relax and pressure decreases
- ventricles contract causing the volume to decrease and pressure to increase
- AV valves close
- SL valves open and blood is forced into the aorta and pulmonary artery
explain the process that leads to the cardiac cycle repeating
- ventricles and atria relax
- pressure is higher in pulmonry artery and aorta
- SL valves close
- blood returns to the heart as the pressure in the vena cava and pulmonary vein is greater than in atria
- cycle repeats
what is cardiac ouput
the volume of blood pumped by the heart per minute
what is the equation to calculate cardiac ouput
cardiac ouput = stroke volume x heart rate
define heartrate
include units
the number of beats per minute (bpm)
define stroke volume
include units
the volume of blood pumped during each heartbeat (cm^3)
what is the role of arteries
carry blood from the heart to the rest of the body
explain 3 key features of arteries
- thick outer walls that can withstand pressure
- elastic tissue to help stretch when the ventricles contract and recoil when the ventricle relaxes. This helps maintain pressure
- they have an inner lining called endothelium which is smooth. This reduces friction
what is the role of arterioles
arteries divide into smaller blood vessels which carry blood from arteries to capillaries under a lower pressure
what is the role of veins
take blood back to the heart from the body
what is the role of capillaries
- smallest blood vessels
- site of substance exchange
explain 4 key features of capillaries
- walls are one cell thick which allows for a short diffusion pathway
- contains fenestrations which allows large molecules to leave the blood vessel
- they have a narrow lumen which reduces flow rate, giving more time for diffusion
- endothelial cells are smooth and flat, this reduces friction
tissue fluid is formed from ……
blood plasma
explain the formation of tissue fluid and how it is returned
- in the arterial end:
- hydrostatic pressure inside the capillaries is higher than the tissue fluid
- this pressure forces fluid out of the capillaries and into tissue space
- proteins stay in the capillary becaue they are too large
- this reduces the water potential of the capillary
- hydrostatic pressure lowers
- in the venous end:
- hydrostatic pressure of the capillary is lower than the tissue fluid, therefore tissue is forced back into the capillaries
- water re enters the capillary by osmosis
- any tissue fluid that does not return to the capillary is drained away from the tissues by the lymphatic system
- this fluid is referred to as lymph
describe how tissue fluid is formed and how it is returned to the circulatory system
(5 marks)
- high hydrostatic pressure
- forces water / fluid out of the capillary
- large proteins remain in capillary
- these causes a low water potential in capillart
- water enters capillary by osmosis
- any tissue that does not return to the capillary is drained away and referred to as lymph
what is cardiovascular disease
general term used to describe diseases associated with the heart and blood vessels
what is coronary heart disease
any interference with the coronary arteries which supply blood to the heart muscle itself
give 5 risk factors for heart disease
- age
- gender
- genetic factors
- stress
- smoking
