TRANSPORT IN HUMANS Flashcards
The cardiovascular system is made up of:
- the heart
- blood vessels
- blood
what is systemic circulation?
when blood is pumped out of the left ventricle through the aorta traveling to the whole body (except lungs) and then returns to the heart through vena cava
what is pulmonary circulation?
when blood is pumped out of the right ventricle through the pulmonary artery and travels to the lungs then returns to the heart by pulmonary veins
what are arteries, veins and capillaries?
arteries: take blood away from the heart
veins: take blood into the heart
capillaries: link arteries and veins to bring the blood as close to cells as possible for faster diffusion
what are the 3 blood vessel layers?
tunica intima (inner coat) tunica media (middle coat) tunica externa (outer coat)
what is tunica intima?
inner coat
made up of squamous epithelium which is smooth to reduce friction
what is tunica media?
middle coat
made up of elastic fibers and some collagen fibers
what is tunica externa?
outer coat
made up of collagen and some elastic fibers
what is the structure of an artery?
thick wall
narrow lumen to increase blood pressure
tunica media has a lot of elastic fibers to allow the arterial wall to stretch as blood passes through with high pressure making it wider and reduce the pressure slightly so that the artery doesn’t burst
tunica externa has a lot of collagen fibers to provide strength
what is the structure of arterioles?
are smaller than arteries
branch off arteries
have more smooth muscle which allows them to constrict and control the blood flow of capillaries
what is the structure of veins?
thin walls
wide lumen
tunica media is very thin and contains fewer elastic and collagen fibers than arteries
how does blood flow through veins?
contraction of skeletal muscles:
by contracting they would squeeze the nearby vein increasing the pressure
valves:
prevent backflow of blood away from the heart
what is the structure of venules?
drain blood from capillaries and bring it to veins
contains small muscle that allows it to constrict and control blood flow through capillaries
what is the structure of capillaries?
smallest blood vessel
form capillary beds that bring blood as close to cells as possible
one cell thick allowing efficient diffusion
narrow lumen so only one RBC can pass through at a time allowing more time for substances to diffuse in and out
what are the heart chambers and what do they receive and pump?
left atrium: receives oxygenated blood from the lungs through the pulmonary vein and pumps it to the left ventricle
left ventricle: receives oxygenated blood and pumps it to the whole body through the aorta
right atrium: receives deoxygenated blood from the whole body through the vena cava and pumps it to the right ventricle
right ventricle: receives deoxygenated blood and pumps it to the lungs through the pulmonary artery
what are the hearts vessels?
aorta: pumps oxygenated blood from heart to body tissues
pulmonary vein: transports oxygenated blood from lungs to heart
superior vena cava: transports deoxygenated blood from the upper body to the heart
inferior vena cava: transports deoxygenated blood from the lower body to the heart
pulmonary arteries: transports deoxygenated blood from the heart to lungs
coronary vessels: branch from aorta and supply the heart with blood for it to respire and release energy to contract and pump blood
why are ventrical walls thicker than atrium walls?
because ventricles transport and pump blood outside of the heart with high pressure and atria only pump blood to the ventricles
why is the left ventricles wall thicker than the right ventricle?
because the left ventricle pumps blood with a higher pressure to the whole body whilst the right ventricle pumps blood to the nearby lungs
what’re the adaptations of red blood cells?
they’re very small (7Mm): makes it easy to squeeze through capillaries
biconcave-disc shape: which increases surface area therefor increasing rate of diffusion
have no nucleus or organelles: allowing more space for hemoglobin to carry the max amount of oxygen
large amount of hemoglobin: to transport oxygen
how is tissue fluid formed?
as blood flows from arteries to capillaries, the high pressure forces water and small molecules out of the capillary wall into the spaces between tissues forming tissue fluid
where does tissue fluid leave and enter capillaries?
tissue fluid tends to leave the capillaries at the arterial end and enter back at its venous end
what are the two pressures inside capillaries?
blood pressure entering the capillary forces water and small molecules out of the capillary wall
osmotic pressure brings water back into the capillary as the plasma proteins that remain in the blood create low water potential inside the capillary drawing water back in by osmosis
what is lymph and how is it formed?
not all tissue fluid is returns to the capillaries, the excess drains into the lymphatic system by lymph vessels forming lymph
lymph enters the lymphatic vessel through valves that allow it to enter but not exit
lymph passes through lymph nodes which contain WBC’s that filter the lymph trapping pathogens
blood, tissue fluid and lymph:
blood:
present in vessels
made up of plasma, RBC’s, WBC’s and platelets
transports substances around the body
tissue fluid:
present around tissues
similar to blood but has less proteins and no RBC’s
provides tissues with oxygen and nutrients and removes carbon dioxide and waste
lymph:
present in lymphatic vessels
no RBC’s, WBC’s present from lymph nodes and has less oxygen and now fats
carries fluid from tissues to heart
what is the cardiac cycle?
the sequence of events which makes up 1 heartbeat
what happens in arterial systole?
the arterial muscle contracts and ventricular muscle relaxes
the pressure in atria forces blood through the AV valves into the ventricles
semilunar valves close to prevent back flow of blood
what is ventricular systole?
ventricular muscle contracts and arterial muscle relaxes
the pressure in ventricle is more than in the atrium which pushes the AV valves shit and pushes open the semilunar valves flowing the blood into the arteries
what is ventricular diastole?
ventricular and arterial muscles relax and as pressure drops, the atria will fill with the blood and semilunar valves will close
as pressure in the atria increases, AV valves open and blood flows into the ventricles
