Transcript Blood Vessels & Circulation Cardiovascular System

Blood Vessels & Circulation
Cardiovascular System - 2
for student copy
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
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
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
Aorta
– Ascending Aorta
• begins @ aortic semilunar valve
– rt & lt coronary arteries
• supply rt & lt sides of heart
– Aortic Arch
• 3 important branches: brachiocephalic trunk, lt
common carotid, lt subclavian
– Descending Aorta
• travels 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
• descends slightly to the left of the
vertebral column
• retroperitoneal
• Branches:
1. 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
–
inferior surface of diaphragm
2. Suprarenal arteries
–
Adrenal glands
3. Renal arteries
–
kidneys
4. Gonadal arteries
–
Testicular or Ovarian
5. 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
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
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
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