BLOOD VESSELS
&
CIRCULATION
Anatomy & Physiology
Circulation of Blood

left side heart  aorta  branches of aorta
(arteries)  arterioles  capillaries 
venules  veins  vena cava  right side of
heart  pulmonary circulation  left side of
heart
Arteries





any blood vessel carrying blood away from heart
designed to withstand higher pressure than veins
elastic: must swell to take up blood expelled by the
heart
swelling stretches elastic tissue & keeps the blood
pressure fairly high between heart beats
small arteries (arterioles)have muscles that control
their diameters (precapillary sphincters): used to
control blood flow thru an organ
cross-section of artery
Capillaries



where materials delivered to/from cells 
blood
walls 1 squamous cell thick: so diffusion
very fast
not elastic
Types of Capillaries
Veins




any blood vessel with blood flowing toward
the heart
low pressure vessels
can expand to accommodate differing
volumes of blood flow
contain valves to stop backflow of blood
cross-section of vein with valve
Comparing Arteries & Veins
Blood Flow





active organs like the liver, brain, kidneys
have high blood flows @ rest
Kidney: ~25% of cardiac output
GI tract & liver: ~25%
Muscle circulation @ rest: ~20%
Brain: ~ 15%
Adaptions for Exercise


during exercise: blood flow to active muscles
greatly increases: up to 80% of cardiac
output
Blood flow to skin increases or decreases to
regulate body temperature
Questions?


What do you think happens to blood flow to
your stomach during exercise?
What do you think happens to blood flow to
your heart during exercise?
Blood Flow Through Organs

regulated by nerves & chemical agents
 both
cardiac output & blood vessel diameter
controlled by hormones & nerves
 controlled by ANS

increasing blood pressure can increase blood
flow
increasing blood pressure  increases
cardiac output  constricts many
arterioles  more blood volume to other
organs
Pulmonary Circuit


circuit of blood vessels from heart  lungs
heart
rt ventricle of heart pumps blood thru
pulmonary trunk  branches into rt & lt
pulmonary arteries  smaller arterioles 
capillaries that surround the alveoli (little
air sacs) where oxygenation of RBCs & get
rid of carbon dioxide
Pulmonary Circuit cont’d

from capillaries  venules which merge into
larger & larger veins until they merge into
the pulmonary veins: 2 pulmonary veins
from each lung empty into lt atrium
Remember!


Pulmonary Trunk & Pulmonary Arteries
carry deoxygenated blood to lungs
Pulmonary Veins carry oxygenated blood
into left side of heart
Aorta
 Ascending
 begins
 rt
Aorta
@ aortic semilunar valve
& lt coronary arteries
 supply
 Aortic
rt & lt sides of heart
Arch
3
important branches: brachiocephalic trunk, lt
common carotid, lt subclavian
 Descending
 travels


Aorta
posterior to heart
portion in thorax called thoracic aorta
Portion in abdominal cavity called abdominal aorta
Common Carotids


branch into:
External Carotid arteries
 supply
blood to neck, esophagus, pharynx,
larynx, lower jaw, face

Internal Carotid arteries
 supply
blood to the brain (with the rt & lt
vertebral arteries: branches of subclavian
arteries)
Arteries of Upper Extremities

Axillary artery:
 branch
of
subclavian artery
 becomes Brachial
artery in the arm
 branches
into
Radial (pulse)&
Ulnar arteries in
lower arm
Branches of the Abdominal Aorta



1.
descends slightly to the left of the vertebral
column
retroperitoneal
Branches:
Celiac Trunk (3 branches)



Lt gastric artery: stomach
Splenic artery: spleen: stomach, & pancreas
Common Hepatic Artery: liver, stomach,
gallbladder, & duodenum
Branches of the Abdominal Aorta
2. Superior Mesenteric Artery:

pancreas, duodenum, small intestines,
most of large intestines
3. Inferior mesenteric Artery:

terminal portion of the colon, sigmoid
colon, & rectum
Branches of the Abdominal Aorta
5 Paired Arteries from
Abdominal Aorta
1.
Inferior phrenic arteries

2.
Suprarenal arteries

3.
kidneys
Gonadal arteries

5.
Adrenal glands
Renal arteries

4.
inferior surface of diaphragm
Testicular or Ovarian
Lumbar arteries

vertebrae, spinal cord, abdominal wall
Iliac Arteries



Abdominal Aorta branches into rt & lt
Common Iliac Arteries @ L4 level
each branches  internal & external iliac
arteries @ level of lumbosacral joint
Internal Iliac Arteries:
 bladder,

external genitalia, uterus, vagina
External Iliac Arteries:
 blood
to lower extremities
Iliac Arteries & Branches
External Iliac Arteries

when cross over to medial surface of thigh
become Femoral Arteries
 branches



to deep femoral & superficial femoral
when reaches knee becomes Popliteal Artery
where it branches  posterior & anterior
Tibial arteries
Posterior Tibial Artery divides  Medial &
Plantar Arteries
Arteries of the Lower Extremities
Systemic Veins

Most veins run parallel to arteries of same
name
Superior & Inferior Vena Cava



SVC: large vein that receives blood from
upper body (head, neck, upper limbs)
IVC: large vein that receives blood from the
lower body (lower limbs, pelvis, abdomen)
both return blood to right atrium
Systemic Veins

Internal Jugular descends parallel to
common carotid arteries  brachiocephalic
veins(just as they merge with the subclavian
veins
Veins of the Upper Extremity


Radial & Ulnar
veins parallel
arteries of same
name then merge
to become Brachial
vein  axillary
vein  subclavian
vein
Vein draw blood
from: median
cubital
Veins of the Abdomen & Pelvis

External Iliac veins
receive blood from
the lower
extremities --> join
with Internal Iliac
veins to form the rt
& lt Common Iliac
Veins  fuses with
the IVC
Veins of Abdomen & Pelvis
Hepatic Portal System



Blood leaving the digestive organs by veins is
rich in nutrients….instead of returning
directly to IVC  heart this blood is shunted
to liver first
This way liver can store, convert, detoxify, or
excrete materials as necessary
Hepatic Portal vein enters liver with
nutrient rich blood