b3 Flashcards
what is osmosis?
the movement of water across a partially-permeable membrane from an area of high conc to an area of low conc
how are villi adapted?
large surface area
very thin wall
where does blood come into the heart?
through the vena cava
what is in red blood cells?
haemoglobin and oxygen.
how do wbc get rid of unwanted organisms?
they produce antibodies and antitoxins
what are platelets and what do they do?
fragments of cells, they form blood clots to prevent blood flowing out.
what are the 3 types of blood vessels?
arteries, veins and capillaries.
do arteries have a thin wall?
no, they have a thick wall(due to moving blood under high pressure)
do veins go toward the heart?
yes
do veins have thin walls?
yes
do capillaries have thick walls?
no, because they need permeable walls for oxygen and nutrients can diffuse through them.
what does xylem move?
water and minerals.
what does the phloem move?
sugars and food.
out of xylem and phloem what moves things up+down?
phloem
what is homeostasis?
maintaining a constant internal environment.
