Transport In Humans Flashcards
Order of layers in arteries and veins
Tunica intima, media, adventita
Heart
Right side:
In: vena cava, into right atrium, through tricuspid valve, into right ventricle, out through pulmonary artery. Thinner.
Left side:
In: pulmonary vein, into left atrium, through bicuspid valve into left ventricle, out through aorta. Thicker. Between them: septum
capillaries
Contain Endothelial cells and nucleus, 1
cell thick walls, pressure higher than vein
What is a phagocyte
Kills pathogens by engulfing and digesting them, has a lobed nucleus
What is a lymphocyte
Fights pathogens by producing specific antibodies. When the antibodies attach to the pathogens it attracts phagocytes to engulf them. Has a large nucleus.
Why simple unicellular organisms can rely on diffusion.
They have a larger SA:Vol ratio so diffusion is quicker, short diffusion distance.
Arteries
Elastic fibre: maintains pressure
Muscle: withstands pressure
Veins
Less pressure so less elastic tissue and muscle. Valves to prevent back flow.
What are plasma and platelets
Plasma: carries digested food; glucose, amino acids, urea, hormones and CO2. Distributes heat and energy and is straw coloured.
Platelets: seals cuts and wounds (with fibrin)
to prevent blood loss and entry of pathogens.
Circulatory system
Pulmonary artery: from heart to lung (deoxygenated) Pulmonary vein: from lung to heart (oxygenated) Aorta: away from heart to body Renal artery: to kidneys Renal vein: away form kidneys Hepatic portal vein: to liver Hepatic vein: away from liver Vena cava: back to heart from body
Experiment on heart rate
Increase intensity
• why? Muscles work harder, need more oxygen and glucose, heart rate increase to meet demand.
Caffeine
•why? Stimulant, causes receptors to initiate a faster heart rate.
Adrenaline
• why? Hormone released in response to stress, to prepare body for action (fight or flight)
why do humans need a double circulatory system
- they are big
- used to maintain speed of blood flow
- maintains a big blood pressure
- blood flows twice through heart for each route once around the body
