1. Fig. 13.5
Copyright © McGraw-Hill Education. Permission required for reproduction or display. CO 2 O 2
Brain
Circulation to brain
and tissues of head
Aorta
Circulation to
upper limbs
CO2
Pulmonary arteries O2
Pulmonary trunk
Pulmonary vein O2
CO2
Heart
Pulmonary
circulation
Digestive tract
circulation
Liver
circulation
Kidney
Renal
circulation
Circulation to
lower limbs
CO2 O2

2. Fig. 13.1-2 Tunica adventitia Tunica media (elastic tissue
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tunica
adventitia
Tunica media
(elastic tissue
and smooth muscle)
Connective tissue
Tunica
intima
Endothelium and
basement membrane
(a) Elastic arteries. The tunica media is mostly
elastic connective tissue. Elastic arteries
recoil when stretched, which prevents blood
pressure from falling rapidly.
Tunica adventitia
Elastic
connective tissue
Tunica
media
Smooth muscle
Elastic
connective tissue
Connective tissue
Tunica
intima
Endothelium and
basement membrane
(b) Muscular arteries. The tunica media is
a thick layer of smooth muscle. Muscular
arteries regulate blood flow to different
regions of the body.

3. Atherosclerotic plaque
Fig
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Endothelium
Vessel wall
Atherosclerotic plaque

4. Fig
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tunica
adventitia
Tunica media
(elastic tissue
and smooth muscle)
Connective tissue
Tunica
intima
Endothelium and
basement membrane
(a) Elastic arteries. The tunica media is mostly
elastic connective tissue. Elastic arteries
recoil when stretched, which prevents blood
pressure from falling rapidly.
Tunica adventitia
Elastic
connective tissue
Tunica
media
Smooth muscle
Elastic
connective tissue
Connective tissue
Tunica
intima
Endothelium and
basement membrane
(b) Muscular arteries. The tunica media is
a thick layer of smooth muscle. Muscular
arteries regulate blood flow to different
regions of the body.
Tunica adventitia
Tunica media
Tunica intima
(c) Arterioles. All three tunics are present;
the tunica media consists of only one or
two layers of circular smooth muscle cells.
Endothelium
(d) Capillaries. Walls consist of only a
simple endothelium surrounded by
delicate loose connective tissue.

5. Arteriole Precapillary sphincters Capillaries Capillary network Venule
Fig. 13.3
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Arteriole
Precapillary
sphincters
Capillaries
Capillary
network
Venule

6. Fig. 13.1
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Tunica
adventitia
Tunica
adventitia
Tunica media
(elastic tissue
and smooth muscle)
Tunica media
Connective tissue
Tunica
intima
Connective tissue
Endothelium and
basement membrane
Tunica
intima
Endothelium and
basement membrane
(a)
Elastic arteries. The tunica media is mostly
elastic connective tissue. Elastic arteries
recoil when stretched, which prevents blood
pressure from falling rapidly.
(g)
Large veins. All three tunics are present.
The tunica media is thin but can regulate vessel
diameter because blood pressure in the venous
system is low. The predominant layer is the
tunica adventitia.
Tunica adventitia
Elastic
connective tissue
Tunica
media
Tunica adventitia
Smooth muscle
Elastic
connective tissue
Tunica media
Connective tissue
Tunica
intima
Connective tissue
Endothelium and
basement membrane
Tunica
intima
Endothelium and
basement membrane
(b)
Muscular arteries. The tunica media is
a thick layer of smooth muscle. Muscular
arteries regulate blood flow to different
regions of the body.
(f)
Small and medium veins. All three
tunics are present.
Tunica adventitia
Tunica intima
Tunica media
Tunica intima
(c)
Arterioles. All three tunics are present;
the tunica media consists of only one or
two layers of circular smooth muscle cells.
(e)
Venules. Only the tunica
intima resting on a delicate
layer of dense connective
tissue is present.
Endothelium
(d)
Capillaries. Walls consist of only a
simple endothelium surrounded by
delicate loose connective tissue.

7. ©Ed Reschke/Photolibrary/Getty Images
Fig. 13.2
Copyright © McGraw-Hill Education. Permission required for reproduction or display. V V A A
LM 250x
Tunica intima
Tunica media
Tunica adventitia
©Ed Reschke/Photolibrary/Getty Images

8. Valve closed Vein Valve open Direction of blood flow Fig. 13.4
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Valve closed
Vein
Valve open
Direction of
blood flow

9. Fig. 13.21 1 When the cuff pressure is high
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1
When the cuff pressure is high
enough to keep the brachial
artery closed, no blood flows
through it, and no sound is
heard.
Degree to which
brachial artery is
open during:
300
Systole
Diastole
250 2
When cuff pressure decreases
and is no longer able to keep
the brachial artery closed, blood
is pushed through the partially
opened brachial artery,
producing turbulent blood flow
and a sound. Systolic pressure
is the pressure at which a sound
is first heard.
No sound 1
Blocked
200 2
Sound is
first heard.
150
Blocked or
partially
open
Systolic pressure
(120 mm Hg)
Korotkoff
sounds
100 3
Diastolic pressure
(80 mm Hg) 3
As cuff pressure continues to
decrease, the brachial artery
opens even more during
systole. At first, the artery is
closed during diastole, but as
cuff pressure continues to
partially opens during diastole.
Turbulent blood flow during
systole produces Korotkoff
sounds, although the pitch of
the sounds changes as the
artery becomes more open.
Sound
disappears. 50 4
Arm
No sound
Open 4
Eventually, cuff pressure
decreases below the
pressure in the brachial
artery, and it remains open
during systole and diastole.
Nonturbulent flow is
reestablished, and no
sounds are heard. Diastolic
pressure is the pressure at
which the sound disappears.
Pressure
cuff
Elbow

10. Venules, veins, and venae cavae
Fig
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
140
120
Systolic pressure
Mean blood
pressure
Pulse
pressure
100 80
Pressure (mm Hg)
Diastolic
pressure 60 40 20
Aorta
Venules, veins, and venae cavae
Arteries
Arterioles
Capillaries

11. Fig. 13.24 1 At the arterial end of the capillary, the movement of
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1
At the arterial end of the
capillary, the movement of
fluid out of the capillary due
to blood pressure is greater
than the movement of fluid
into the capillary due to
osmosis.
One-tenth volume passes into lymphatic capillaries. 3
Nine-tenths volume returns to capillary.
Net
movement
of fluid
out of the
capillary
into the
interstitial
space
Net
movement
of fluid
into the
capillary
from the
interstitial
space
Outward movement of
fluid due to blood pressure
Inward movement of fluid
due to osmosis 2
At the venous end of the
capillary, the movement of
fluid into the capillary due to
osmosis is greater than the
movement of fluid out of the
capillary due to blood
pressure.
Inward movement of
fluid due to osmosis
Outward movement of
fluid due to blood pressure 1 2 3
Approximately nine-tenths of
the fluid that leaves the
capillary at its arterial end
reenters the capillary at its
venous end. About one-tenth
of the fluid passes into the
lymphatic capillaries.
Blood flow
Arterial end
Venous end

12. Arteriole Precapillary sphincters Capillaries Capillary network Venule
Fig. 13.3
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Arteriole
Precapillary
sphincters
Capillaries
Capillary
network
Venule

13. Fig. 13.25 Blood flow increases Blood flow decreases 1 2
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Blood flow
increases
Blood flow
decreases 1 2
Smooth muscle of
precapillary sphincter
relaxes.
Smooth muscle of
precapillary sphincter
contracts.
Blood
flow
Blood
flow 1
Relaxation of precapillary sphincters.
Precapillary sphincters relax as the tissue concentration of O2
and nutrients, such as glucose, amino acids, and fatty acids,
decreases. The precapillary sphincters also relax as CO2
concentration increases and pH decreases. 2
Contraction of precapillary sphincters. Precapillary sphincters
contract as the tissue concentration of O2 and nutrients, such as
glucose, amino acids, and fatty acids, increases. The precapillary
sphincters also contract as the CO2 concentration decreases and
pH increases.

14. Vasomotor center in medulla oblongata Spinal cord Sympathetic
Fig
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Vasomotor center
in medulla oblongata
Spinal cord
Sympathetic
nerve fibers
Blood vessels
Sympathetic
chain

15. Fig. 13.27 Carotid sinus baroreceptors 1 Baroreceptors in the carotid
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Carotid sinus
baroreceptors 1
Baroreceptors in the carotid
sinus and aortic arch monitor
blood pressure. 1
Aortic arch
baroreceptors 2
Sensory nerves conduct action
potentials to the
cardioregulatory and
vasomotor centers in the
medulla oblongata.
Sensory nerve fiber 3 2 3
Increased parasympathetic
stimulation of the heart
decreases the heart rate.
Vagus nerve (parasympathetic) 4
Increased sympathetic
stimulation of the heart
increases the heart rate
and stroke volume.
Cardioregulatory
and vasomotor
centers in the
medulla oblongata 4
Sympathetic
nerves 5
Increased sympathetic
stimulation of blood vessels
increases vasoconstriction.
Sympathetic
chain 5
Blood vessels

16. Fig
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 3 4
Actions
Reactions
Baroreceptors in the carotid arteries
and aorta detect an increase in
blood pressure.
Effectors Respond:
Heart rate and stroke
volume decrease;
blood vessels dilate.
The cardioregulatory center and the
vasomotor center in the brain alter
activity of the heart and blood
vessels (baroreceptor reflex), and
the adrenal medulla decreases
secretion of epinephrine. 2
Homeostasis Disturbed:
Blood pressure increases.
Homeostas is Restored:
Blood pressure decreases. 5
Blood pressure
(normal range) 1
Start here
Blood pressure
(normal range) 6
Homeostasis Disturbed:
Blood pressure decreases.
Homeostasis Restored:
Blood pressure increases.
Actions
Reactions
Baroreceptors in the carotid arteries
and aorta detect a decrease in blood
pressure.
Effectors Respond:
Heart rate and stroke
volume increase; blood
vessels constrict.
The cardioregulatory center and the
vasomotor center in the brain alter
activity of the heart and blood
vessels (baroreceptor reflex), and the
adrenal medulla increases secretion
of epinephrine (adrenal medullary
mechanism).

17. Fig. 13.29 1 Chemoreceptors in the carotid and aortic bodies
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1
Chemoreceptors in the
carotid and aortic bodies
monitor blood O2, CO2, and
pH.
Carotid body
chemoreceptors 1
Aortic body
chemoreceptors
Sensory nerves 2
Chemoreceptors in the
medulla oblongata monitor
blood CO2 and pH.
Sensory nerves 3 3
Decreased blood O2,
increased CO2, and
decreased pH decrease
parasympathetic stimulation
of the heart, which
increases the heart rate. 2
Chemoreceptors
in the medulla
oblongata
Vagus nerve (parasympathetic) 4 4
Decreased blood O2,
increased CO2, and
decreased pH increase
sympathetic stimulation of
the heart, which increases
the heart rate and stroke
volume.
Cardioregulatory
and vasomotor
centers in the
medulla oblongata
Sympathetic
nerves 5
Decreased blood O2,
increased CO2, and
decreased pH increase
sympathetic stimulation of
blood vessels, which
increases vasoconstriction.
Sympathetic
chain 5

18. Fig. 13.30 1 Increased stimulation 1
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1
Increased
stimulation 1
The same stimuli that increase sympathetic stimulation of the
heart and blood vessels cause action potentials to be carried to
the medulla oblongata.
Medulla
oblongata 2
Epinephrine
and
norepinephrine 2
Descending pathways from the medulla oblongata to the spinal
cord increase sympathetic stimulation of the adrenal medulla,
resulting in secretion of epinephrine and some norepinephrine.
Spinal
cord
Sympathetic
nerve fiber
Adrenal medulla
Sympathetic
chain

19. Fig
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Decreased
blood pressure
Liver 1
The kidneys detect decreased
blood pressure, resulting in
increased renin secretion. 1
Angiotensinogen
Renin 2 2
Renin converts
angiotensinogen, a protein
secreted from the liver, to
angiotensin I.
Kidney
Angiotensin I 6 3
Angiotensin-converting
enzyme in
lung capillaries 3
Angiotensin-converting
enzyme in the lungs converts
angiotensin I to angiotensin II.
Aldosterone 4
Angiotensin II is a potent
vasoconstrictor, resulting in
increased blood pressure. 5
Angiotensin II
Adrenal
cortex 4 5
Angiotensin II stimulates the
adrenal cortex to secrete
aldosterone.
Vasoconstriction 6
Aldosterone acts on the
kidneys to increase Na+
reabsorption. As a result, urine
volume decreases and blood
volume increases, resulting in
increased blood pressure.
Increases water reabsorption
and decreases urine volume
Increased
blood pressure

20. Fig. 13.32 Baroreceptors (aortic arch, carotid sinus) detect decreased
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Baroreceptors
(aortic arch,
carotid sinus)
detect decreased
blood pressure.
Hypothalamic
nerve cells detect
increased
osmotic pressure.
Hypothalamic
nerve cell
Posterior pituitary
ADH
Increased
reabsorption
of water
Blood vessel
Kidney
Vasoconstriction
Increased blood volume
Increased blood pressure

21. pressure in right atrium
Fig
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Increased blood
pressure in right atrium
ANH
Kidney
Increased Na+
excretion and
increased water
loss result in
decreased BP.
ANH secretion

22. Fig
Copyright © McGraw-Hill Education. Permission required for reproduction or display. 3 4 A
ctions R
eactions
Atrial natriuretic mechanism:
Cardiac muscle cells detect increased
atrial blood pressure; secretion of
atrial natriuretic hormone increases.
Effectors Respond:
Vasodilation decreases
peripheral resistance to
blood flow. More Na+ and
water are lost in the urine,
decreasing blood volume.
Renin-angiotensin-aldosterone
mechanism:
The kidneys detect increased blood
pressure; production of angiotensin II
and secretion of aldosterone from the
adrenal cortex decrease. 2
Homeostasis Disturbed:
Blood pressure increases. 5
Homeostasis Restored:
Blood pressure decreases.
Blood pressure
(normal range) 1
Start here
Blood pressure
(normal range) 6
Homeostasis Disturbed:
Blood pressure decreases.
Homeostasis Restored:
Blood pressure increases.
Actions
Reactions
Renin-angiotensin-aldosterone
mechanism:
The kidneys detect decreased blood
pressure; production of angiotensin
II and secretion of aldosterone from
the adrenal cortex increase.
Effectors Respond:
Vasoconstriction increases
peripheral resistance to
blood flow. Less Na+ and
water are lost in the urine,
increasing blood volume.
ADH (vasopressin) mechanism:
Baroreceptors detect decreased
blood pressure, resulting in
decreased stimulation of the
hypothalamus and increased ADH
secretion by the posterior pituitary.

23. Atherosclerotic plaque
Fig
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Endothelium
Vessel wall
Atherosclerotic plaque