BLOOD VESSELS/ VASCULAR

SYSTEM
• The vascular system consists of the arteries, 3 DISTINCT LAYERS of ARTERIES
capillaries, and veins through which heart pump
blood throughout the body. 1) Tunica interna—the innermost layer
• MAJOR function • composed of layer of simple squamous epithelium
o exchange material between the blood called endothelium
and tissues which takes place in the • composed of endothelial cell
capillaries 2) Tunica media—middle layer
• Makes up the bulk of the arterial wall
• Includes smooth muscle fibers
TYPES of BLOOD VESSELS
• The thickest layer of arterial wall
• CT muscle cells, elastic fibers
1. ARTERIES—strong and elastic
3) Tunica externa—the outer layer
vessels
• Arterioles—small branch of artery t • Thin and chiefly consist of CT, with irregularly
communicates with the capil ary elastic & collagenous fibers
network
• Function—carry blood away from the
heart to the organs & tissues except MAJOR ARTERIES OF THE SYSTEMIC
pulmonary artery CIRCULATION
• Very high blood pressure has thick
muscular wall • Aorta—main vessel of arterial division
➢ 2 Types o The only branch of the ascending aorta is
the right and left coronary arteries
a) Elastic arteries—is similar to which serves the heart with blood
collagen but contains more elastin
(protein) than any other blood
vessels
--expands as heart beats
b) Muscular arteries—built for
strength and distribute blood to
the major organs; branch into
smaller arterioles
 ARTERIAL BRANCHES OF
ASCENDING AORTA & THE
AORTIC ARCH
Artery Definition & branch
supply
Coronary Myocardium Ascending
(muscle of aorta
heart)
Brachiocephalic Right arm and
head
Right common
carotid
Right
subclavian
Left common 2nd branch of
carotid the aortic arch
--the left side
of head
a) Left internal
carotid artery—
serves the brain
b) Left external
carotid artery—
serves the skin,
muscle of the
head and neck
Left 3rd branch of Aortic arch
subclavian the aortic arch
--left shoulder
and arm
Vertebral serves Subclavian
artery cervical artery
vertebrae
and circle
of Willis.
Brachial supplies Axillary
artery the upper artery
arm
Radial Supplies Brachial
artery the artery
forearm
Ulnar supplies Brachial
artery the artery
forearm
Volar supplies Radial &
arch the hand ulnar
artery
 ARTERIAL BRANCHES OF THE
THORACIC AORTA
Intercostal arteries Consists of 10 pairs
• Supplies skin,
muscles,
bones and
trunk,
thoracic wall
Superior phrenic Supplies diaphragm
artery
Pericardial artery Supplies dorsal (back)
surface of
pericardium
Esophageal artery Supply esophagus
Bronchial artery Supply bronchioles (a
CT of the lungs)
 ARTERIAL BRANCHES OF THE Dorsal Supplies
pedis dorsum of
ABDOMINAL AORTA artery the foot
Plantar Supplies
arches the foot
Inferior phrenic Supplies diaphragm
artery (sits at chest) Posterior tibial artery Supplies back of lower
Lumbar artery Serve lung muscles leg
Peroneal
Middle sacral artery Supply sacrum, coccyx, artery
buttocks Plantar Supplies
Celiac trunk 1st branch of arches the foot
abdominal aorta
Left Supplies
gastric stomach
artery
Hepatic Supplies
artery liver
Splenic Supplies
artery spleen
Superior mesenteric Supplies most of small
artery (unpaired) intestines and 1st half
of the small intestine
Suprarenal artery Supplies adrenal
glands (branch of
inferior phrenic
artery)
Renal arteries Supplies kidneys
Inferior mesenteric Supplies most of the
artery colon and rectum
Gonadal arteries Supplies gonads and
(right and left) reticular artery
Common iliac arteries --the 2 largest
(right and left) vessels that receive
blood from the
abdominal aorta.
Divides into:
Internal Supplies the
iliac pelvic organs
artery (bladder,
rectum &
reproductive
organs)
External Supplies the
iliac lower pelvis
artery to legs;
enters the
thighs and
become the
______
Femoral --large
artery artery &
main
arterial
supply to
thighs and
legs
Serves the
thigh
Popliteal Splits to
artery anterior &
posterior
arteries
--supplies
back of the
knee
 2. VEINS—carry blood away from the
CEREBRAL CIRCULATION heart
-----4 MAJOR ARTERIES------ • carrying blood from the capillaries
• are generally more flexible than the
1) Internal carotid arteries arteries and they collapse if blood
o Supply the vest of cerebrum & both pressure is not maintained, veins may
eyes rupture
o Blood must 1st pass through anastomosis • has reservoir that is 60 to 75 % of
(connection of vein to vein and artery to water in the circulating blood volume
artery)
2) Cerebral arterial circle (circle of Willis) • Function—carry deoxygenated blood
o Protects the brain from the body tissues to the heart
3) Internal jugular veins except the
o Hhhhhh o 4 pulmonary veins—that
4) Vertebral arteries carry oxygenated blood from
o Supply the cerebellum, brain stem, the lungs to the left atrium
posterior part of cerebrum o Hepatic portal system of
o Branch: subclavian artery veins—carries blood from the
capillaries of the intestine to
the capillaries of the sinusoids
(passage of blood in the liver)
of the liver (gets about 70 %
oxygenated blood via the
portal vein)
o Hypothalamic-hypophyseal
system—capillaries of the
hypothalamus (in the pituitary
gland) unite to form veins that
divide into a second set of
sinusoidal capillaries in the
anterior pituitary gland; also
carrying oxygenated blood
---There are more muscles in arteries than vein
*Anastomosis—connection or joining of vessels which
is artery to artery or vein to vein. It is to provide
alternal pathways for the flow of blood

• Venules—vessels that carry blood from

capillaries to a vein ( has thinner walls and
less muscle compared to arteries)
o Has thinner walls with less muscle
o Have valve that prevents the
back flow of blood

3 DISTINCT LAYERS OF VEINS

1) Tunica interna—the innermost layer
o composed of layer of
smooth_____ but at intervals this
lining is folded to form_______ ANASTAMOSIS
a. Semilunar and bicuspid valves—
permit blood to flow in only one • The connection or joining of vessels that is artery
direction, restricting backflow in to artery or vein to vein
heart
b. Venous valves—which are derived
from folds of the tunica intima
are especially abundant in the legs
where gravity opposes the return
of blood to the heart, prevent
backflow
2) Tunica media—middle layer
o It includes smooth muscle fibers
o Thin because veins do not regulate
blood ______ and blood flow to
capillaries as arteries do
3) Tunica externa—the outer layer
o Thin and chiefly consists of not as
much as fibrous connective tissue
as necessary because blood
pressure in veins is very low
MAJOR VEINS of the SYSTEMATIC VEINS DRAINING BLOOD FROM HEAD &
CIRCULATION NECK
Cranial venous Collect Internal
sinuses deoxygenated jugular vein
blood which drain
CNS and skull in
1) Superior vena cava—drains____ the internal
2) Inferior vena cava jugular vein going
to superior vena
o Drains deoxygenated blood from the cava to heart
organs/ cells and tissues part of the Internal jugular Drains blood from Brachiocephalic
body and empty their deoxygenated vein face and neck vein
blood into the right atrium External jugular Drains superficial Subclavian vein
• 1 and 2 are connected to right atrium wherein vein face and neck
they drain blood from upper and lower part of Subclavian vein Drains blood from Brachiocephalic
the body shoulders vein
Brachiocephalic Are large veins Superior vena
• Blood from different organs because arteries vein that receive cava
supplied, where there is metabolism of cells venous drainage
from the
subclavian,
vertebral, and
internal jugular
veins on their
respective sides
or this is the
upper body
 VEINS DRAINING BLOOD FROM THE VEINS DRAINING BLOOD FROM
ARM & SHOULDER TRUNKS
• Veins—going to heart and not cells Brachiocephalic Major vein returning Superior
• Arteries---from heart to cells vein blood to superior vena vena cava
cava
Radial and ulnar Deep veins Brachial veins • Right
veins draining the brachiocephalic
forearm vein—joins the
Cephalic vein Provides for the Axillary vein left
superficial brachiocephalic
drainage of the vein
lateral aspect Azygos vein Deep structure of Superior
of the arm and chest and abdomen, vena cava
empties into the link SVC and IVC,
axillary vein drains back, thoracic,
Basilic vein A superficial vein Axillary vein (the and abdominal walls
that drains the large blood and organs in the
medial aspect vessel that viscera (mediastinum)
of the arm and convey blood of Hepatic portal a single vein that Inferior
empties into the the lateral vein drains the digestive (brought by
brachial vein aspect of tract organs and abdominal
proximally thorax, axilla, carries the blood aorta)
______ through the liver vena cava
Subclavian vein Receives venous Brachiocephalic before it enters the
blood from the vein systematic circulation
arm through Renal vein Drains blood from the LRV
the axillary vein kidney
and from the Hepatitic (R Drains blood from the Inferior
skin and muscles and L) vein liver vena cava
of the head Testicular or Drains blood from IVC and
through the ovarian vein testes to ovaries left renal
external jugular vein
vein Internal iliac Drains blood from Common
vein rectum, bladder, iliac vein
reproductive organs
External iliac Drains blood from leg Common
vein and abdominal wall iliac vein
Common iliac Drains blood from the Inferior
vein lower abdomen vena cava
VEINS DRAINING INTO THE INFERIOR
VENA CAVA
Inferior vena cava * longer than SVC
* Returns blood to the
right atrium to body
regions below the
diaphragm (thin muscular
organ dividing ________)
Anterior and posterior * ______(calf and foot)
tibial vein and peroneal *the posterior tibial vein
vein becomes popliteal vein at
the knee and then the
femoral vein in the thigh
Great saphenous vein *Longest vein in the body
*They receive the
superficial drainage of the
leg (deoxygenated blood)
Common iliac (R and L) Formed by the union of
vein the external iliac vein and
internal iliac vein on its
own side
*which drains in the pelvis
*joined to form the IVC
which then ascends
superiorly to the right
side of the heart
VEINS DRAINING BLOOD FROM LEG &
HIP

Anterior and Drains blood Popliteal vein

posterior tibial from leg and
vein lower foot
Popliteal vein Drains blood Femoral vein
from the knee
Small saphenous Drains blood Femoral vein
vein from the
superficial foot
and thighs
Great saphenous Drains blood Femoral vein
vein from superficial
foot, leg, and
thigh

Femoral vein Drains blood External iliac

from the thigh vein

External iliac vain Drains blood Common iliac

from leg and vein
abdominal wall

Common iliac vein Draisn blood Inferior vena

from leg and cava
lower abdomen

Inferior vena cava Drains blood Right atrium

from the lower
body going to
the right atrium
In artery, thick because of strong pressure
• Arterial blood pressure is much greater than CIRCULATION OF BLOOD
venous blood pressure due to ventricle
contraction of the heart in the left ventricle of Two main circuits
the heart 1) Pulmonary circulation—supplies bloos
• After artery BP decreases rapidly within the only to the lungs
capillaries with 0 pressure o Carries deoxygenated blood from the
• 1 to 2 seconds of exchange of gases in capillaries heart to the lungs, where carbon dioxide
• Capillary flow—the blood leaves the heart for is removed and oxygen is added
about 30 to 40 cm/sec then to slow down 2.5 o It then returns the newly______ blood
cm/sec by the time it reaches arterioles to to the heart for distribution to the rest
<1mm/sec or 0 in capillaries of the )______
• 1 sec to 2 sec is the dropping of oxygen for the o Pulmonary circulation takes 4 to 8 sec of
body pulmonary artery
o Pulmonary—lungs

3. CAPILLARIES
• Microscopic vessels with walls mostly
one cell thick
RESEARCH: HOW LONG IT TAKES FOR THE EXCHANGE OF
• The thin capillary walls are full of OXYGEN IN THE HEART????
pores allows the passage of water
and small particles of dissolved ---HOW THICK IS CAPILLARIES???
materials
• Are distributed throughout the body, a) Right side S of the heart (Right
except in dead outer layer of the skin atrium) pumps deoxygenated blood
and lenses of the eyes to lungs
• FUNCTION: where materials (oxygen, b) Right ventricles pump blood to
nutrients, carbon dioxide, energy) is pulmonary trunk
exchanged between blood and cells c) Pulmonary trunk branches into
• Found near muscle cells, organs, etc. pulmonary artery
• Walls are only one cell thick d) Pulmonary arteries carry
• Diffusion takes place deogenated blood to the lungs for
exchange of gases
• Very small e) Oxygenated blood returns to heart
(left atrium) via pulmonary veins
2) Systematic circulation—supplies all
the cell, tissue, and organs of the body
o Supplies oxygenated blood and also
returns deoxygenated blood
o Systematic circulation is about 25 to 30
seconds
a) Left side of the heart (right atrium
and left ventricle) pumps blood
through the body
b) Left ventricle pumps oxygenated
blood into the aorta
c) Aorta branches into many arteries
that travel to organs to thoracic
aorta
d) Arteries branch into many arterioles
in tissue
e) Aortic branch into thin waled
capillaries for exchange of gases and
nutrients
f) Deoxygenated blood begins its
return to venules
g) Venules emerge into veins and
return to right atrium
 CUTANEOUS (SKIN) Circulation
1. The arrangement of blood vessels in the skin
allows for the increase or decrease of heat
radiation from the skin
2. When body temperature increases, more blood
flows to the superficial layers, from which heat
radiates to the body
3. In contrast, when the body needs to conserve
heat, blood is shunted away from the surface of
the skin through deep arteriovenous
anastomosis (vessels that bypass the capillary
bed).