Check Your Understanding 1.
Te hematocrit is the percentage of
blood that is occupied by erythrocytes. It is normally about 45%.
can prevent blood loss by forming clots when a blood vessel is damaged.
Blood can prevent infection because it contains antimicrobial proteins
and white blood cells.
Plasma proteins are not used as fuel for body
cells because their presence in blood is required to perform many key
Each hemoglobin molecule can transport four O
. Te heme
portion of the hemoglobin binds the O
Te kidneys’ synthesis of
erythropoietin is compromised in advanced kidney disease, so RBC pro-
duction decreases, causing anemia.
Monocytes become macrophages
in tissues. Neutrophils are also voracious phagocytes.
“Trombopoietin” is derived from the same word as “thrombocyte.”
It is the hormone that promotes platelet formation.
Amos’s red bone
marrow is spewing out many abnormal white blood cells, which are
crowding out the production of normal bone marrow elements. Te lack
of normal white blood cells allows the infections, the lack of platelets fails
to stop bleeding, and the lack of erythrocytes is anemia.
Te three steps
of hemostasis are vascular spasm, platelet plug formation, and coagula-
Fibrinogen is water soluble, whereas ﬁbrin is not. Prothrombin
is an inactive precursor, whereas thrombin acts as an enzyme. Most fac-
tors are inactive in blood before activation and become enzymes upon
activation. (Tere are exceptions, such as ﬁbrinogen and calcium.)
Trombocytopenia (platelet deﬁciency) results in failure to plug the
countless small tears in blood vessels, and so manifests as small purple
spots. Hemophilia A results from the absence of clotting factor VIII.
Nigel has anti-A antibodies in his blood and type B agglutinogens on
his RBCs. He can donate blood to an AB recipient, but he should not re-
ceive blood from an AB donor because his anti-A antibodies will cause a
If Emily has a bacterial meningitis, a diﬀerential
WBC count would likely reveal an increase in neutrophils because neu-
trophils are a major body defense against bacteria.
Hemoglobin F has
a higher aﬃnity (binding strength) for oxygen than adult hemoglobin
does. It has 2 α and 2 γ chains rather than 2 α and 2 β chains.
Review Questions 1.
Case Study 1.
Saline infusion temporarily replaces the lost blood vol-
ume, thereby helping to restore Mr. Malone’s circulation.
contain oxygen-carrying hemoglobin. While the saline replaces lost
blood volume, it cannot replace the hemoglobin in the lost RBCs. (In
acute trauma, the rule of thumb is to use no more than 2 liters of normal
saline before starting PRBCs, so that the hematocrit does not drop below
O negative blood cells bear neither the A nor the B nor the Rh
agglutinogens (antigens). People with O negative blood are sometimes
called “universal donors” because their cells lack the antigens responsible
for most major transfusion reactions.
Mr. Malone’s blood would have
anti-B antibodies (agglutinins) so he would not be able to receive B or
AB blood. He can safely receive A and O blood.
If doctors had trans-
fused type B or AB blood into Mr. Malone’s circulation, his anti-B
antibodies would have “attacked” these foreign cells and caused them
to agglutinate. Tis transfusion reaction can be dangerous because the
agglutinated cells can clog small vessels. In addition the transfused cells
would begin to hemolyze (rupture) or would be destroyed by phagocytes.
Check Your Understanding 1.
Te mediastinum is the medial cavity of
the thorax within which the heart, great vessels, and trachea are found.
Te layers of the heart wall are the endocardium, the myocardium,
and the epicardium. Te epicardium is also called the visceral layer of
the serous pericardium. Tis is surrounded by the parietal layer of the
serous pericardium and the ﬁbrous pericardium.
Te serous ﬂuid de-
pituitary via action potentials traveling down axons that connect the
hypothalamus to the posterior pituitary.
Drinking alcoholic beverages
inhibits ADH secretion from the posterior pituitary and causes copious
urine output and dehydration. Te dehydration causes the hangover
LH and FSH are tropic hormones that act on the gonads,
±SH is a tropic hormone that acts on the thyroid, and AC±H is a tropic
hormone that acts on the adrenal cortex. (If you said growth hormone,
that’s also a good answer, as GH causing the liver to release IGFs might
also be considered a tropic eﬀect.)
Tyroid hormone increases basal
metabolic rate (and heat production) in the body. Parathyroid hormone
increases blood Ca
levels in a variety of ways. Calcitonin at high (phar-
macological) levels has a Ca
-lowering, bone-sparing eﬀect. (At normal
blood levels its eﬀects in humans are negligible.)
cells release thyroid hormone, parathyroid cells in the parathyroid gland
release parathyroid hormone, and parafollicular (C) cells in the thy-
roid gland release calcitonin.
Glucocorticoids are stress hormones
that, among many eﬀects, increase blood glucose. Mineralocorticoids
increase blood Na
(and blood pressure) and decrease blood K
nadocorticoids are male and female sex hormones that are thought to
have a variety of eﬀects (for example, contribute to onset of puberty,
sex drive in women, pubic and axillary hair development in women).
Melatonin is used by some individuals as a sleep aid, particularly
to counter jet lag.
When we say Sharon is diabetic, this means that
she has insuﬃcient insulin action in her body. Te most likely explana-
tion for Sharon’s behavior is that she has taken too much insulin and
is experiencing hypoglycemia. You could help her by making sure she
immediately ingests a sugary snack or drink.
Diabetes mellitus is
due to a lack of insulin production or action, whereas diabetes insipidus
is due to a lack of ADH. Both conditions are characterized by produc-
tion of copious amounts of urine. You would ﬁnd glucose in the urine
of a patient with diabetes mellitus, but not in the urine of a patient with
Te gonadal hormones are steroid hormones. A
major endocrine gland that also secretes steroid hormones is the adrenal
Te heart produces atrial natriuretic peptide (ANP). ANP
decreases blood volume and blood pressure by increasing the kidneys’
production of salty urine.
, produced in inactive form by
the skin, increases intestinal absorption of calcium.
Te decline in
growth hormone with age contributes to muscle atrophy. Te decline in
estrogen contributes to osteoporosis in women.
Review Questions 1.
(1)c, (2)a and b, (3)f, (4)d,
(5)e, (6)g, (7)a, (8)h, (9)b and e, (10)a;
Case Study 1.
Rationale for orders: As Mr. Gutteman is unconscious,
the level of damage to his brain is unclear. Monitoring his responses
and vital signs every hour will provide information for his care provid-
ers about the extent of his injuries. ±urning him every 4 hours and
providing careful skin care will prevent decubitus ulcers (bedsores)
as well as stimulating his proprioceptive pathways.
condition is termed diabetes insipidus, a condition in which insuf-
ﬁcient quantities of antidiuretic hormone (ADH) are produced or
released. Diabetes insipidus patients excrete large volumes of urine but
do not have glucose or ketones present in the urine. Te head trauma
could have damaged Mr. Gutteman’s hypothalamus, which produces
the hormone, or injured his posterior pituitary gland, which releases
ADH into the bloodstream.
Diabetes insipidus is not life threatening
for most individuals with normal thirst mechanisms, as they will be
thirsty and drink to replenish the lost ﬂuid. However, Mr. Gutteman
is comatose, so his ﬂuid output must be monitored closely so that the
volume lost can be replaced by IV line. His subsequent recovery may
be complicated if he has suﬀered damage to his hypothalamus, which
houses the thirst center neurons.