Download Brachial artery

A


closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the
body
 The


functions of the cardiovascular system
To deliver oxygen and nutrients to cells and tissues
To remove carbon dioxide and other waste products from
cells and tissues
Midsternal line
2nd rib
Sternum
Diaphragm
Point of
maximal
intensity
(PMI)
(a)
Figure 11.1a
Superior
vena cava
Pulmonary
trunk
Aorta
Parietal
pleura (cut)
Left lung
Pericardium
(cut)
Diaphragm
Apex of
heart
(c)
Figure 11.1c
Brachiocephalic trunk
Left common carotid artery
Superior vena cava
Left subclavian artery
Right pulmonary artery
Aortic arch
Ascending aorta
Ligamentum arteriosum
Left pulmonary artery
Pulmonary trunk
Left pulmonary veins
Right pulmonary
veins
Left atrium
Right atrium
Right coronary artery
in coronary sulcus (right
atrioventricular groove)
Anterior cardiac vein
Auricle of left atrium
Circumflex artery
Left coronary artery in
coronary sulcus (left
atrioventricular groove)
Left ventricle
Right ventricle
Great cardiac vein
Marginal artery
Small cardiac vein
Inferior vena cava
(a)
Anterior interventricular
artery (in anterior
interventricular sulcus)
Apex
Figure 11.3a
 Pericardium—a
 Heart
double-walled sac
Wall
Three layers

Epicardium


Myocardium


Outside layer
Middle layer- cardiac muscle
Endocardium

Inner layer- Endothelium
Superior vena cava
Aorta
Left pulmonary artery
Right pulmonary artery
Left atrium
Right atrium
Left pulmonary veins
Right pulmonary
veins
Pulmonary semilunar valve
Fossa ovalis
Right atrioventricular
valve (tricuspid valve)
Left atrioventricular valve
(bicuspid valve)
Aortic semilunar valve
Left ventricle
Right ventricle
Chordae tendineae
Interventricular septum
Inferior vena cava
Myocardium
Visceral pericardium
(b) Frontal section showing interior chambers and valves.
Figure 11.3b
 Right
and left side act as separate pumps
 Four chambers

Atria


Receiving chambers
 Right atrium
 Left atrium
Ventricles

Discharging chambers
 Right ventricle
 Left ventricle
 Systemic

circulation
Blood flows from the left side of the heart
through the body tissues and back to the right
side of the heart
 Pulmonary

circulation
Blood flows from the right side of the heart to
the lungs and back to the left side of the heart
Capillary beds
of lungs where
gas exchange
occurs
Pulmonary Circuit
Pulmonary
arteries
Pulmonary
veins
Aorta and
branches
Venae
cavae
Left
atrium
Left
ventricle
Right
atrium
Heart
Right
ventricle
Systemic Circuit
KEY:
Oxygen-rich,
CO2-poor blood
Oxygen-poor,
CO2-rich blood
Capillary
beds of all
body tissues
where gas
exchange
occurs
Figure 11.4
 Allow
blood to flow in only one direction to prevent
backflow
 Four


valves
Atrioventricular (AV) valves—between atria and ventricles

Bicuspid (mitral) valve (left side of heart)

Tricuspid valve (right side of heart)
Semilunar valves—between ventricle and artery

Pulmonary semilunar valve

Aortic semilunar valve
 Blood
in the heart chambers does not nourish the
myocardium
 The
heart has its own nourishing circulatory system
consisting of

Coronary arteries—branch from the aorta to supply the
heart muscle with oxygenated blood

Cardiac veins—drain the myocardium of blood

Coronary sinus—a large vein on the posterior of the heart,
receives blood from cardiac veins
 Blood
sinus
empties into the right atrium via the coronary
 Arteries


Aorta- Leaves left ventricle
Pulmonary arteries -Leave right ventricle
 Veins

Superior and inferior venae cavae


Enter right atrium
Pulmonary veins (four)

Enter left atrium
 Veins

Superior and inferior venae cavae


Enter right atrium
Pulmonary veins (four)

Enter left atrium
Superior
vena cava
Sinoatrial (SA)
node (pacemaker)
Atrioventricular
(AV) node
Right atrium
Bundle branches
Purkinje fibers
Left atrium
Atrioventricular
(AV) bundle
(bundle of His)
Purkinje fibers
Interventricular
septum
Figure 11.7
 Once


SA node starts the heartbeat
Impulse spreads to the AV node
Then the atria contract
 At
the AV node, the impulse passes through
the AV bundle, bundle branches, and
Purkinje fibers
 Blood is ejected from the ventricles to the
aorta and pulmonary trunk as the ventricles
contract
 Homeostatic



imbalance
Heart block—damaged AV node releases them
from control of the SA node; result is in a slower
heart rate as ventricles contract at their own
rate
Ischemia—lack of adequate oxygen supply to
heart muscle
Fibrillation—a rapid, uncoordinated shuddering of
the heart muscle
Homeostatic
imbalance (continued)
 Tachycardia—rapid heart rate over
100 beats per minute
 Bradycardia—slow heart rate less
than 60 beats per minutes
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
1
Mid-to-late diastole
(ventricular filling)
Isovolumetric
contraction phase
2
Ventricular systole
(atria in diastole)
Figure 11.8, step 2a
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
1
Mid-to-late diastole
(ventricular filling)
Ventricular
Isovolumetric
contraction phase ejection phase
2
Ventricular systole
(atria in diastole)
Figure 11.8, step 2b
 Transport
blood to the tissues and back

Carry blood away from the heart
 Arteries
 Arterioles
Exception: ???

Exchanges between tissues and blood
 Capillary beds
Return blood toward the heart
 Venules
 Veins
Exception: ??

(a)
Artery
Vein
Figure 11.10a
Valve
Tunica intima
• Endothelium
• Loose connective tissue
Internal elastic
lamina
Tunica media
• Smooth muscle
• Elastic fibers
External elastic lamina
Tunica externa
• Collagen fibers
Lumen
Artery
Venule
Arteriole
Capillary
network
Lumen
Vein
Basement membrane
Endothelial cells
(b)
Capillary
Figure 11.10b
Lumen of
capillary
Intercellular
cleft
Vesicles
Endothelial
fenestration
(pore)
4 Transport
via vesicles
3 Diffusion
through pore
1 Direct
diffusion
through
membrane
2 Diffusion through
intracellular cleft
Interstitial fluid
Figure 11.23
 Arteries
have a thicker tunica media than
veins
 Capillaries are only one cell layer (tunica
intima) to allow for exchanges between
blood and tissue
 Veins have a thinner tunica media than
arteries


Veins also have valves to prevent backflow of
blood
Lumen of veins are larger than arteries
 Veins:



Have a thinner tunica media
Operate under low pressure
Have a larger lumen than arteries
 To
assist in the movement of blood back to
the heart:


Larger veins have valves to prevent backflow
Skeletal muscle “milks” blood in veins toward
the heart
Valve (open)
Contracted
skeletal
muscle
Valve (closed)
Vein
Direction of
blood flow
Figure 11.11
 Capillary


beds consist of two types of vessels
Vascular shunt—vessel directly connecting an
arteriole to a venule
True capillaries—exchange vessels


Oxygen and nutrients cross to cells
Carbon dioxide and metabolic waste products cross
into blood
Vascular shunt
Precapillary sphincters
True
capillaries
Terminal arteriole
Postcapillary
venule
(a) Sphincters open; blood flows through true
capillaries.
Figure 11.12a
Figure 11.12b
 Pulse

Pressure wave of blood
 Monitored
at “pressure points” in arteries
where pulse is easily palpated
 Pulse averages 70 to 76 beats per minute
at rest
Superficial temporal artery
Facial artery
Common carotid artery
Brachial artery
Radial artery
Femoral artery
Popliteal artery
Posterior tibial
artery
Dorsalis pedis
artery
Figure 11.19
 Measurements
by health professionals are
made on the pressure in large arteries



Systolic—pressure at the peak of ventricular
contraction
Diastolic—pressure when ventricles relax
Write systolic pressure first and diastolic last
(120/80 mm Hg)
 Pressure
in blood vessels decreases as
distance from the heart increases
−10
Venae cavae
Veins
Venules
Capillaries
Arterioles
Arteries
60
Aorta
Pressure (mm Hg)
120
Systolic pressure
100
80
Diastolic
pressure
40
20
0
Figure 11.20
Blood pressure
120 systolic
70 diastolic
(to be measured)
Brachial
artery
(a) The course of the
brachial artery of
the arm. Assume a
blood pressure of
120/70 in a young,
healthy person.
Figure 11.21a
Pressure
in cuff
above 120;
no sounds
audible
120 mm Hg
Rubber cuff
inflated with
air
Brachial
artery
closed
(b) The blood pressure
cuff is wrapped
snugly around the
arm just above the
elbow and inflated
until the cuff
pressure exceeds the
systolic blood
pressure. At this
point, blood flow into
the arm is stopped,
and a brachial pulse
cannot be felt or
heard.
Figure 11.21b
Pressure
in cuff
below 120,
but above 70
120 mm Hg
70 mm Hg
Sounds
audible in
stethoscope
(c) The pressure in the cuff
is gradually reduced
while the examiner
listens (auscultates) for
sounds in the brachial
artery with a
stethoscope. The
pressure read as the
first soft tapping
sounds are heard (the
first point at which a
small amount of blood
is spurting through the
constricted artery) is
recorded as the systolic
pressure.
Figure 11.21c
Pressure
in cuff
below 70;
no sounds
audible
70 mm Hg
(d) As the pressure is
reduced still further,
the sounds become
louder and more
distinct; when the
artery is no longer
constricted and blood
flows freely, the
sounds can no longer
be heard. The
pressure at which the
sounds disappear is
recorded as the
diastolic pressure.
Figure 11.20d
 BP

is blood pressure
BP is affected by age, weight, time of day, exercise,
body position, emotional state
 CO
is the amount of blood pumped out of the
left ventricle per minute
 PR is peripheral resistance, or the amount of
friction blood encounters as it flows through
vessels

Narrowing of blood vessels and increased blood
volume increases PR
 BP
= CO  PR
 Normal

Normal



140 to 110 mm Hg systolic
80 to 75 mm Hg diastolic
Hypotension



human range is variable
Low systolic (below 110 mm Hg)
Often associated with illness
Hypertension


High systolic (above 140 mm Hg)
Can be dangerous if it is chronic