542 Answers to Illustration Questions9–5: The iris changes the size of the pupil. (A step
further: Which set of iris muscles constricts the
pupil and which dilates it? One more step:
Which nerves are involved; think ANS.)
9–6: The ganglion neurons form the optic nerve.
The rods and cones are the photoreceptors.
9–7: The first structure to vibrate is the tympanic
membrane, and second is the malleus. (A step
further: Be sure you can complete the pathway
of vibrations for hearing.)
9–8: The vibrations of the sound waves cause the
round window to bulge out, preventing damag-
ing pressure in the cochlea.
9–9: The canals and cochlear duct contain fluid. The
receptors are the hair cells below the tectorial
membrane. (A step further: Name the cranial
nerve and lobe of the cerebral cortex concerned
with hearing.)
9–10: In part A: Gravity pulls on the otoliths and
bends the hair cells. In part B: Movement of the
head causes the hair cells to sway. (A step fur-
ther: Name the cranial nerve and parts of the
brain concerned with equilibrium.)CHAPTER 1010–1: The thyroid hormones are carried by the blood
throughout the body (true of all hormones) to
their target organs.
10–2: ACTH, TSH, FSH, and LH all affect other
endocrine glands.
10–3: In part A: ADH and oxytocin are stored in the
posterior pituitary. In part B: Releasing hor-
mones from the hypothalamus stimulate secre-
tion of anterior pituitary hormones. (Let’s go a
step further: What kind of feedback mechanism
stimulates the anterior pituitary gland?)
10–4: Growth hormone increases mitosis and protein
synthesis, both of which directly contribute to
growth.
10–5: Both the increase in protein synthesis and the
production of energy from all types of foods
contribute to growth and maintenance of bones
and muscles. (These functions of thyroxine and
T 3 are necessary for other organs as well.)
10–6:Calcitonin promotes calcium retention in
bones. PTH contributes to the activation of
vitamin D in the kidneys. (A step further: What
is the stimulus for secretion of each of these
hormones?)10–7: Bones are a reservoir for calcium.
10–8: Insulin enables cells to take in glucose. The
stimulus for insulin secretion is hyper-
glycemia, such as after a meal.
10–9: Epinephrine causes vasodilation and increases
cell respiration in skeletal muscles; norepi-
nephrine causes vasoconstriction. (A step fur-
ther: How does epinephrine increase blood
pressure?)
10–10: Aldosterone directly increases the reabsorp-
tion of sodium ions and the excretion of potas-
sium ions by the kidneys. (A step further:
What are the indirect effects of these func-
tions of aldosterone?)
10–11: Under the stimulus of cortisol, most tissues
will use fats and excess amino acids for energy
production, and glucose will be stored as
glycogen in the liver.
10–12: A target cell must have a specific receptor for
the hormone, either in the cell membrane
(protein hormones) or in the cytoplasm
(steroid hormones).CHAPTER 1111–1: Blood plasma is mostly water (91.5%); RBCs
are the most numerous cells.
11–2: Normoblasts and reticulocytes are usually
found in the red bone marrow because they
are immature stages of RBC development.
(Let’s go a step further: Which cell shown
here is an immature WBC?)
11–3: The center of a RBC is pale because it is thin-
ner than the edge; this is where the nucleus
was.
11–4: Iron and amino acids are recycled; the heme of
the hemoglobin is excreted as bilirubin. (A
step further: Where can iron be stored?)
11–5: Answers will vary, but if you are type O you
can donate to types A, B, and AB as well as
type O. If you are type A you can donate to
type A or AB, and so on.
11–6: The diameter of the arteriole is much larger
than that of the capillary, and platelet plugs
would be washed away before they could
cover the opening. Once a fibrin mesh
forms, the platelets are trapped, as are RBCs.
(A step further: What other mechanism
of hemostasis also works in arterioles, and
why?)29Scanlon(p3) App-G 8/17/06 11:08 AM Page 542