540 Answers to Illustration QuestionsCHAPTER 44–1: Simple squamous epithelium is best for diffusion
because it is the thinnest. (Let’s go a step further:
Where is simple squamous epithelium found?)
4–2: Stratified squamous and transitional epithelium
are most similar structurally because both have
several layers.
4–3: The cilia of the trachea sweep mucus and foreign
material upward toward the pharynx.
4–4: The matrix of blood is plasma. Triglycerides are
stored in adipocytes.
4–5: Collagen fibers are the matrix of fibrous CT; cal-
cium salts and collagen fibers form the matrix of
bone.
4–6: Skeletal muscle cells and cardiac muscle cells
have striations, which result from the arrange-
ment of the cells’ contraction proteins. (A step
further: Which type of muscle tissue may be
called “voluntary”?)
4–7: The central neuron has eight processes, which
look alike, but would be one axon and seven den-
drites. (A step further: Where is the nucleus of
the neuron located?)
4–8: The mesentery covers the small and large intes-
tines and the liver.CHAPTER 55–1: Blood vessels are found in the dermis and subcu-
taneous tissue.
5–2: The Langerhans cell can pick up foreign mate-
rial such as a bacterium, and transport it to a
lymph node. (Let’s go a step further: What do
melanocytes produce, and what is its function?)
5–3: A hair shaft is made of keratin. (A step further:
What other human structures are made mostly
of keratin?)
5–4: The nail bed is living layers of the epidermis and
the dermis.CHAPTER 66–1: The osteocytes are living cells and need a good
blood supply, with oxygen and nutrients.
6–2: The frontal bone forms in two parts, which in
the infant skull are still separate. The two parts
will eventually grow together (with no suture).
6–3: In a closed epiphyseal disc, all of the cartilage has
been replaced by bone. (Let’s go a step further:Name the cells that produce bone, that reab-
sorb bone, and that maintain the bone matrix.)
6–4: The vertebrae and facial bones are irregular
bones. (A step further: Name the other bone
categories and give examples of each.)
6–5 and 6–6: The openings at the back of an eye
socket permit passage of the optic nerve and
blood vessels of the eye.
6–7: The foramen magnum is the opening through
which the spinal cord merges with the brain.
6–8: The olfactory foramina are the openings for the
olfactory nerves (sense of smell).
6–9: “Sinus headache” pain is usually from the
frontal sinus and the maxillary sinuses.
6–10: The lumbar vertebra is larger and bulkier than
the thoracic vertebra; the lumbar vertebrae
support more weight. (A step further: What
kind of joint is found between vertebrae?)
6–11: All of the ribs articulate posteriorly with the
thoracic vertebrae.
6–12: The joints of the arm are (from the top):
ball-and-socket joint at the shoulder, hinge
joint at the elbow, pivot joint in the forearm,
gliding joints at the wrist, hinge joints in the
fingers, and a saddle joint at the base of the
thumb.
6–13: The female pelvic inlet is much larger than the
male pelvic inlet; this is an adaptation for child-
birth.
6–14: There is no pivot joint between the tibia and
fibula, and no saddle joint in the big toe.
6–15: The ball-and-socket joint is the most movable;
the symphysis is the least movable.
6–16: These two bones are long bones because each
has an epiphysis. Examples are the joints be-
tween phalanges or between the femur and
tibia.CHAPTER 77–1: When a muscle contracts it shortens and exerts
a pulling force.
7–2: The fitting of an acetylcholine molecule into an
ACh receptor opens a sodium channel in the
sarcolemma. (Let’s go a step further: What
causes a motor neuron to release acetylcholine?)
7–3: The unit of contraction of skeletal muscle is a
sarcomere, shown in picture D. (A step further:
Name the contracting proteins in a sarcomere.)
7–4: Sodium ions enter the cell during depolariza-29Scanlon(p3) App-G 8/17/06 11:08 AM Page 540