13) epinephrine and norepinephrine that are released from the adrenal glands affect
target tissue for a longer period of time than the same substances released from neurons
at their peripheral receptors. why?
a) the adrenal gland releases larger amounts of the neurotransmitters than the neurons.
b) the hormones released from the adrenal glands bind to different receptors than those
released from neurons.
c) there are no enzymes to break down epinephrine and norepinephrine in the blood and
very little in peripheral tissues.
d) the effectors are less sensitive to epinephrine and norepinephrine released by the
adrenal glands.
e) the epinephrine and norepinephrine from the adrenal glands are released by
sympathetic neurons, whereas parasympathetic neurons release these substances at the
effector organs.
14) opsonins function by
a) poisoning and killing invading cells.
b) marking or tagging pathogens so phagocytes can find and ingest them.
c) digesting invading cells directly.
d) poisoning and killing invading cells and marking or tagging pathogens so phagocytes
can find and ingest them.
e) poisoning and killing invading cells, marking or tagging pathogens so phagocytes
can find and ingest them, and digesting invading cells directly.
15) which statement is not true regarding cardiac muscle?
a) cardiac muscle cells must obey the all-or-none law of contraction.
b) cardiac muscle cells rely on a sarcoplasmic reticulum for storage of ca2+ ions.
c) calcium-induced calcium release is the process by which extracellular ca2+ triggers
the release of stored ca2+ from the sarcoplasmic reticulum.
d) intercalated disks contain both desmosomes for firm attachment and gap junctions to
allow communication.
e) the oxygen demand of cardiac muscle cells is high because they have many
mitochondria.