When the flexor muscles of one arm contract in a withdrawal reflex, the extensor
muscles of the other arm contract. This phenomenon is called
A) crossed flexor reflex. B) crossed extensor reflex.
C) flexor extensor reflex. D) ipsilateral reflex.
(
Question 2) The first event in muscle fiber contraction is that
A) the muscle fiber membrane is stimulated and a muscle impulse travels deep into the
fiber through transverse tubules.
B) acetylcholine diffuses across a gap at a neuromuscular junction.
C) calcium ions diffuse from sarcoplasmic reticulum into the sarcoplasm and bind to
troponin molecules.
D) acetylcholine is released from the end of the motor neuron.
(
Question 3) Eighty-year-old Evelyn takes a bisphosphonate drug once a month to keep her bones
strong. She most likely has
A) a hematoma. B) osteoporosis.
C) polydactyly. D) osteogenesis imperfecta.
(
Question 4) A nerve cell membrane becomes depolarized as a result of
A) calcium leaving the nerve cell.
B) some ion channels being opened while others are closed.
C) Na+ being prevented from passing through the membrane.
D) the relative ease with which K+ diffuses into the nerve cell.
(
Question 5) The tough layer of waterproof material that makes up the outermost part of the epidermis
is the stratum lucidum.
Indicate whether the statement is true or false
(
Question 6) The two strands of a DNA molecule have opposite orientation.
Indicate whether the statement is true or false
(
Question 7) At a neuromuscular junction
A) actin and myosin filaments slide past one another.
B) intercalated discs are synthesized.
C) neurotransmitters are released.
D) troponin and tropomyosin exchange places.
(
Question 8) The cells that respond to environmental stimuli are ________.
Fill in the blank(s) with correct word
(
Question 9) Max returns to his dorm room late at night to find his roommate throwing up. The smell
is at first so bad that Max wants to vomit too, but after helping his roommate clean up,
the odor seems to fade. Max has experienced
A) a hallucination.
B) damage to his sensory receptors.
C) sensory adaptation.
D) a response to the decreasing concentration of odorant molecules in the room.
(
Question 10) Which of the following increases the risk of developing osteoporosis?
A) Family history of the condition B) Lack of physical exercise
C) Low intake of dietary calcium D) All of the above
Quick Reply
