Transcript Ch20.Blood.Vessels

The Blood Vessels
~The Vascular System
Ch 20
Leonardo Da Vinci
Human Anatomy
Sonya Schuh-Huerta, Ph.D.
Types of Blood Vessels
• Arteries  carry blood Away from the heart
• Capillaries  smallest blood vessels
– The site of exchange of molecules between
blood & tissue fluid
• Veins  carry blood toward the heart
Structure of Blood Vessels
• Composed of 3 layers (= tunics)
– Tunica intima  endothelium; composed of
simple squamous epithelium
– Tunica media  sheets of smooth muscle
• Contraction = vasoconstriction
• Relaxation = vasodilation
– Tunica externa  composed of C.T.
• Lumen
– Central blood-filled space of a vessel
Structure of Blood Vessels
Tunica intima
Endothelium
Subendothelial layer
Internal elastic membrane
Tunica media
(smooth muscle and
elastic fibers)
Valve
External elastic membrane
Tunica externa
(collagen fibers)
Lumen
Artery
Capillary
network
Lumen
Vein
Basement membrane
Endothelial cells
(b)
Capillary
Structure of Arteries, Veins, & Capillaries
Vein
Artery
(a)
Structure of Arteries, Veins, & Capillaries
Lab iScopy Pix
Types of Arteries
• Elastic arteries  the largest arteries
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–
–
Diameters range from 2.5 cm to 1 cm
Includes the aorta and its major branches
Sometimes called conducting arteries
High elastin content dampens surge of BP
Vasa
vasorum
Elastin
Lumen
Tunica
Tunica
Tunica
externa
media
intima
(a) Elastic artery (aorta, 12)
Types of Arteries
• Muscular
(“distributing”)
arteries
– Lie distal to elastic arteries
– Diameters range from
1 cm to 0.3 mm
– Includes most named
arteries
– Tunica media is thick
– Unique feature
• Internal & external
elastic laminae
External
Internal
Lumen
elastic
elastic
membrane membrane
Tunica
Tunica
externa
media
(b) Muscular artery (40)
Types of Arteries
• Arterioles
– Smallest arteries
– Diameters range from 0.3 mm to 10 µm
– Larger arterioles possess all three tunics
– Diameter of arterioles
controlled by
• Local factors in
the tissues
• Sympathetic
nervous system
Lumen
Endothelium
Tunica media
(c) Small arteriole (285)
Capillaries
• Smallest blood vessels
– Diameter from 8–10 µm
• RBCs pass through single file!!!
– Site-specific functions of capillaries
• Lungs  oxygen enters blood, carbon dioxide
leaves
• Small intestines  receive digested nutrients
• Endocrine glands  pick up/release hormones
• Kidneys  removal of nitrogenous wastes
RBCs in a Capillary – Single File
Capillary Beds
• Network of capillaries running through
tissues
• Precapillary sphincters
– Regulate the flow of blood to tissues
• Tendons & ligaments  poorly vascularized
• Epithelia & cartilage  avascular
– Receive nutrients from nearby CT
Capillary Beds
Vascular shunt
Precapillary
sphincters Metarteriole Thoroughfare
channel
True
capillaries
Terminal arteriole
Postcapillary venule
(a) Sphincters open—blood flows through
true capillaries.
Capillary Beds
Terminal arteriole
Postcapillary venule
(b) Sphincters closed—blood flows through
metarteriole—thoroughfare channel & bypasses
true capillaries (no blood/O2 to tissue)
Capillary Permeability
• Endothelial cells  held together by tight
junctions & desmosomes
• Intercellular clefts  gaps of unjoined
membrane
– Small molecules can enter & exit
• 2 types of capillary
– Continuous  most common
– Fenestrated  have pores; least common
Continuous Capillary
Pericyte
Red blood
cell in lumen
Intercellular
cleft
Endothelial
cell
Basement
membrane
Tight junction
Endothelial
nucleus
Pinocytotic
vesicles
(a) Continuous capillary. Least permeable and most
common (e.g., skin, muscle).
Fenestrated Capillary
Pinocytotic
vesicles
Red blood
cell in lumen
Fenestrations
(pores)
Endothelial
nucleus
Basement membrane
Tight junction
Intercellular
cleft
Endothelial
cell
(b) Fenestrated capillary. Large fenestrations (pores)
increase permeability. Occurs in special locations
(e.g., kidney, small intestine).
Routes of Capillary Permeability
• 4 routes into & out of capillaries
– Direct diffusion
– Through intercellular clefts
– Through cytoplasmic vesicles
– Through fenestrations (= pores)
Low Permeability Capillaries
• Blood-Brain Barrier
– Capillaries have complete
tight junctions
– No intercellular clefts present
– Vital molecules pass through
• Highly selective transport mechanisms
– Not a barrier against:
• Oxygen, carbon dioxide, & some anesthetics (ie. many drugs)
Sinusoids
• Wide, leaky capillaries found in some
organs
– Usually fenestrated
– Intercellular clefts are wide open
• Occur in bone marrow, spleen, & liver
– Sinusoids have large diameter & twisted course
Sinusoids
Endothelial
cell
Red blood
cell in lumen
Large
intercellular
cleft
Tight junction
Incomplete
basement
membrane
Nucleus of
endothelial
cell
(c) Sinusoidal capillary. Most permeable. Occurs in special
locations (e.g., liver, bone marrow, spleen).
Veins
• Conduct blood from capillaries toward the heart
• Blood pressure is much lower than in arteries
• Smallest veins  called venules
– Diameters from 8–100 m
– Smallest venules  called postcapillary
venules
• Venules join to form veins
• Tunica externa is the thickest tunic in veins (not
the tunica media)
Mechanisms to Counteract Low
Venous Pressure
Valve (open)
• Valves in some
veins!
– Particularly in limbs
• Skeletal muscle
pump
– Muscles press against
thin-walled veins
– Helps return blood to
heart & prevent pooling
Contracted
skeletal
muscle
Valve (closed)
Vein
Direction of
blood flow
Summary of Blood Vessel Anatomy
Vascular Anastomoses
• Vessels interconnect to form vascular
anastomoses
– Organs receive blood from more than one
arterial source
• Neighboring arteries form arterial
anastomoses
– Provide collateral channels
• Veins anastomose more frequently than
arteries
Vasa Vasorum
• Tunica externa of large vessels have
– Tiny arteries, capillaries, & veins
• Vasa vasorum  “vessels of vessels”
– Nourish outer region of large vessels
• Inner half of large vessels receive
nutrients from luminal blood
Pulmonary Circulation
• Pulmonary trunk leaves the right ventricle
– Divides into right & left pulmonary arteries
• Superior & inferior pulmonary veins
– Carry oxygenated blood into the left atrium
Pulmonary Circulation
Left pulmonary
artery
Air-filled
alveolus
of lung
Aortic arch
Pulmonary trunk
Right pulmonary
artery
O2
Three lobar
arteries to
right lung
CO2
Gas exchange
Pulmonary
capillary
Two lobar arteries
to left lung
Pulmonary
veins
Right
atrium
Pulmonary
veins
Left atrium
Right
ventricle
Left
ventricle
Blood Vessels Throughout Life
• Fetal circulation
– All major vessels in place
by month 3 of development
– Differences between fetal & postnatal
circulation
• Fetus must supply blood to the placenta
• Very little blood is sent through the pulmonary
circuit (lungs not doing gas exchange yet; no
breathing until born)
Shunts Away from the
Pulmonary Circuit
• Foramen ovale
• Ductus arteriosus
Vessels to & from the Placenta
• Umbilical vessels run in the umbilical cord
– Paired umbilical arteries
– Unpaired umbilical vein
• Fetal vessels & structures
– Ductus venosus
– Ligamentum teres
– Ligamentum venosum
Fetal & Newborn Circulation Compared
Fetus
Aortic arch
Superior vena cava
Ductus arteriosus
Ligamentum arteriosum
Pulmonary artery
Pulmonary veins
Heart
Lung
Foramen ovale
Fossa ovalis
Liver
Ductus venosus
Ligamentum venosum
Hepatic portal vein
Umbilical vein
Ligamentum teres
Inferior vena cava
Umbilicus
Abdominal aorta
Common iliac artery
Umbilical arteries
Medial umbilical ligaments
Urinary bladder
Umbilical cord
Placenta
(a)
High oxygenation
Moderate oxygenation
Low oxygenation
Very low oxygenation
Disorders of the Blood Vessels
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Aneurysm
Deep vein thrombosis of the lower limb
Venous disease
Microangiopathy of diabetes
Arteriovenous malformation
Varicose veins 
Abdominal Aneurysm
Aortic
aneurysm
Disorders of the Blood Vessels
• Atherosclerosis begins in youth
• Often related to fatty diet, little exercise, etc.
– Consequences evident in middle – old age
– Males (ages 45–65)
• More common than in females
– Females
• Experience heart disease & atherosclerosis later in
life than males
Atherosclerosis
What is one of the best ways to maintain
vascular health…?
Lab Guide to the Vessels
Systemic Circulation
• Systemic arteries
– Carry oxygenated blood away from the heart
– Aorta  largest artery in the body!!!
Major Arteries
Arteries of the head and trunk
Internal carotid artery
External carotid artery
Common carotid arteries
Vertebral artery
Subclavian artery
Brachiocephalic trunk
Aortic arch
Ascending aorta
Coronary artery
Thoracic aorta (above diaphragm)
Celiac trunk
Abdominal aorta
Superior mesenteric artery
Renal artery
Gonadal artery
Inferior mesenteric artery
Common iliac artery
Internal iliac artery
Arteries that supply the
upper limb
Subclavian artery
Axillary artery
Brachial artery
Radial artery
Ulnar artery
Deep palmar arch
Superficial palmar arch
Digital arteries
Arteries that supply the
lower limb
External iliac artery
Femoral artery
Popliteal artery
Anterior tibial artery
Posterior tibial artery
Arcuate artery
(a) Anterior view
Major Arteries – Pulse Points
Superficial temporal
artery
Facial artery
Common carotid
artery
Brachial artery
Radial artery
Femoral artery
Popliteal artery
Posterior tibial
artery
Dorsalis pedis
artery
The Aorta
• Ascending aorta  arises from the left
ventricle
– Branches  coronary arteries
• Aortic arch  lies posterior to the
manubrium
– Branches 
• Brachiocephalic trunk
• Left common carotid
• Left subclavian arteries
The Aorta
Right common carotid
artery
Right subclavian artery
Right internal
jugular vein
Right subclavian vein
Right brachiocephalic
vein
Brachiocephalic trunk
Right pulmonary artery
Left internal
jugular vein
Left subclavian
artery
Left subclavian vein
Left brachiocephalic
vein
Left common carotid
artery
Aortic arch
Left pulmonary artery
Ligamentum arteriosum
Superior vena cava
Thoracic aorta
Ascending aorta
Pulmonary trunk
Right atrium
Left atrium
Right ventricle
Inferior vena cava
Left ventricle
The Aorta
• Descending aorta  continues from the
aortic arch
– Thoracic aorta  in the region of ~T5–T12
– Abdominal aorta  ends at L4
• Divides into right & left common iliac
arteries
Common Carotid Arteries
• Located in the anterior triangle of the neck
• 2 branches of the common carotid artery:
– External carotid artery
– Internal carotid artery
Common Carotid Arteries
• External carotid artery branches:
– Superior thyroid artery
– Lingual artery
– Facial artery
– Occipital artery
– Posterior auricular artery
– Superficial temporal artery
– Maxillary artery
Common Carotid Arteries
• Internal carotid artery branches:
– Optithalmic artery
– Anterior cerebral artery
– Anterior communicating artery
• Forms part of the cerebral arterial circle
– Middle cerebral artery
Arteries of the Head & Neck
Ophthalmic artery
Basilar artery
Vertebral artery
Internal
carotid artery
External
carotid artery
Common
carotid artery
Thyrocervical
trunk
Costocervical
trunk
Subclavian
artery
Axillary
artery
(a) Arteries of the head and neck, right aspect
Branches of
the external
carotid artery
Superficial
temporal artery
Maxillary artery
Occipital artery
Facial artery
Lingual artery
Superior thyroid
artery
Larynx
Thyroid gland
(overlying trachea)
Clavicle (cut)
Brachiocephalic
trunk
Internal thoracic
artery
Vertebral Arteries
• Supply the posterior brain
• Join to form the basilar artery
– Basilar artery divides into 2 posterior cerebral
arteries
• Posterior cerebral arteries connect to the posterior
communicating arteries
Cerebral Arterial Circle
• 2 posterior communicating arteries join the
anterior communicating artery
Anterior
Cerebral arterial circle
(circle of Willis)
Frontal lobe
Optic chiasma
Anterior
communicating
artery
Anterior
cerebral artery
Middle
cerebral
artery
Internal
carotid
artery
Posterior
communicating
artery
Mammillary
body
Posterior
cerebral artery
Basilar artery
Temporal
lobe
Vertebral artery
Pons
Occipital lobe
Cerebellum
Posterior
(c) Major arteries serving the brain (inferior view, right side
of cerebellum and part of right temporal lobe removed)
Arteries of the Upper Limb
• Subclavian artery enters the axilla as the
axillary artery
• Axillary artery becomes the brachial
artery at the inferior border of teres major
• Brachial artery divides into 
Radial artery & ulnar artery
Arteries of the Upper Limb & Thorax
Vertebral artery
Thyrocervical trunk
Costocervical trunk
Common carotid arteries
Right subclavian artery
Suprascapular artery
Thoracoacromial artery
Axillary artery
Left subclavian artery
Brachiocephalic trunk
Posterior intercostal arteries
Subscapular artery
Anterior intercostal artery
Posterior circumflex
humeral artery
Internal thoracic artery
Anterior circumflex
humeral artery
Lateral thoracic artery
Brachial artery
Deep artery of arm
Descending aorta
Common interosseous
artery
Radial artery
Ulnar artery
Deep palmar arch
Superficial palmar arch
Digital arteries
Arteries of the Abdominal Aorta
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Inferior phrenic arteries
Celiac trunk
Superior mesenteric artery
Suprarenal arteries
Renal arteries
Gonadal (testicular or ovarian) arteries
Inferior mesenteric artery
Common iliac arteries
Arteries of the Abdominal Aorta
Hiatus (opening)
for inferior vena cava
Hiatus (opening)
for esophagus
Adrenal (suprarenal)
gland
Celiac trunk
Kidney
Abdominal aorta
Diaphragm
Inferior phrenic artery
Middle suprarenal artery
Renal artery
Superior mesenteric
artery
Lumbar arteries
Gonadal (testicular
or ovarian) artery
Ureter
Inferior mesenteric
artery
Median sacral
artery
Common iliac artery
The Celiac Trunk & Main Branches
Liver (cut)
Diaphragm
Inferior vena cava
Celiac trunk
Common hepatic
artery
Hepatic artery proper
Gastroduodenal
artery
Right gastric artery
Gallbladder
Pancreas
(major portion lies
posterior to stomach)
Duodenum
Abdominal aorta
Esophagus
Left gastric artery
Stomach
Splenic artery
Left gastroepiploic
artery
Spleen
Right gastroepiploic
artery
Superior mesenteric
artery
(a) The celiac trunk and its major branches. The left half of the liver has been removed.
Arteries of Pelvis & Lower Limbs
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Internal iliac arteries
External iliac artery
Femoral artery
Popliteal artery
Anterior tibial artery
Posterior tibial artery
Arteries of the Pelvis
Aorta
Common iliac artery
Internal iliac artery
External iliac artery
(a) Anterior view
Arteries of the Pelvis & Lower Limbs
Common iliac artery
Internal iliac artery
Superior gluteal artery
External iliac artery
Deep artery of thigh
Lateral circumflex
femoral artery
Descending branch
Medial circumflex
femoral artery
Obturator artery
Femoral artery
Adductor hiatus
Popliteal artery
Genicular artery
Anterior tibial artery
Posterior tibial artery
Fibular artery
Dorsalis pedis artery
Arcuate artery
Dorsal metatarsal arteries
(a) Anterior view
Arteries of the Pelvis & Lower Limbs
Popliteal artery
Anterior tibial artery
Posterior
tibial
artery
Lateral plantar
artery
Medial plantar
artery
(b) Posterior view of leg
Fibular artery
Dorsalis pedis
artery (from top of
foot)
Plantar arch
Systemic Veins
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3 major veins enter the right atrium
Superficial veins lie just beneath the skin
Multivein bundles  venous plexuses
Unusual patterns of venous drainage
– Dural sinuses
– Hepatic portal system
Venae Cavae & Tributaries
• Superior vena cava
– Returns blood from body regions superior to
the diaphragm
• Inferior vena cava
– Returns blood from body regions inferior to
the diaphragm
• Superior and inferior vena cava
– Join the right atrium
Major Veins of the Systemic Circulation
Veins of the head and trunk
Dural venous sinuses
External jugular vein
Vertebral vein
Internal jugular vein
Right and left
brachiocephalic veins
Superior vena cava
Great cardiac vein
Hepatic veins
Splenic vein
Hepatic portal vein
Renal vein
Superior mesenteric vein
Inferior mesenteric vein
Inferior vena cava
Common iliac vein
Internal iliac vein
Veins that drain
the upper limb
Subclavian vein
Axillary vein
Cephalic vein
Brachial vein
Basilic vein
Median cubital vein
Ulnar vein
Radial vein
Digital veins
Veins that drain the lower limb
External iliac vein
Femoral vein
Great saphenous vein
Popliteal vein
Posterior tibial vein
Anterior tibial vein
Small saphenous vein
Dorsal venous arch
Dorsal metatarsal veins
Veins of the Head & Neck
• Venous
drainage
– Internal jugular
veins
– External jugular
veins
– Vertebral veins
Ophthalmic vein
Superficial temporal vein
Facial vein
Occipital vein
Posterior auricular vein
External jugular vein
Vertebral vein
Internal jugular vein
Superior and middle
thyroid veins
Brachiocephalic vein
Subclavian vein
Superior vena cava
(a) Veins of the head and neck, right
superficial aspect
Veins of the Head & Neck
• Dural sinuses
– Superior & inferior
sagittal sinuses
– Straight sinus
– Transverse
sinuses
– Sigmoid sinus
Superior sagittal sinus
Falx cerebri
Inferior sagittal sinus
Straight sinus
Cavernous sinus
Confluence of sinuses
Transverse sinuses
Sigmoid sinus
Jugular foramen
Right internal jugular vein
(b) Dural venous sinuses of the brain
Veins of the Thorax
• Azygos vein
• Hemiazygos vein
• Accessory hemiazygos vein
Veins of the Upper Limbs
• Deep veins
– Follow the paths of companion arteries
– Have the same names as the companion
arteries
• Superficial veins
– Visible beneath the skin
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Cephalic vein
Basilic vein
Median cubital vein
Median vein of the forearm
Veins of the Thorax & Right Upper Limb
Brachiocephalic veins
Right subclavian vein
Axillary vein
Brachial vein
Cephalic vein
Basilic vein
Internal jugular vein
External jugular vein
Left subclavian vein
Superior vena cava
Azygos vein
Accessory hemiazygos
vein
Hemiazygos vein
Posterior intercostals
Inferior vena cava
Ascending lumbar vein
Median cubital
vein
Median
antebrachial
vein
Cephalic vein
Radial vein
Basilic vein
Ulnar vein
Deep palmar
venous arch
Superficial palmar
venous arch
Digital veins
Veins of the Abdomen
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Lumbar veins
Gonadal (testicular or ovarian) veins
Renal veins
Suprarenal veins
Hepatic veins
Tributaries of the Inferior Vena Cava
Hepatic veins
Inferior vena cava
Right suprarenal vein
Right gonadal vein
External iliac vein
Inferior phrenic vein
Left suprarenal vein
Renal veins
Left ascending lumbar vein
Lumbar veins
Left gonadal vein
Common iliac vein
Internal iliac vein
(a) Tributaries of the inferior vena cava; venous drainage of
the paired abdominal organs.
Tributaries of the Inferior Vena Cava
Right
Left
Diaphragm
Hepatic veins
Inferior
vena cava
Renal veins
Abdominal aorta
Common
iliac veins
(b) Dissection of the posterior abdominal wall illustrating
abdominal vessels.
The Hepatic Portal System
• A specialized part of the vascular circuit
• Picks up digested nutrients
• Delivers nutrients to the liver for
processing
The Basic Scheme of the Hepatic
Portal System
Hepatic veins
Inferior vena cava
(not part of hepatic
portal system)
Gastric veins
Liver
Hepatic portal vein
Spleen
Inferior vena cava
Splenic vein
Right
gastroepiploic vein
Inferior
mesenteric vein
Superior
mesenteric vein
Small intestine
Large intestine
Rectum
(b) The veins of the hepatic portal system
Veins of the Pelvis & Lower
Limbs
• Deep veins
– Share the name of the accompanying artery
• Superficial veins
– Great saphenous vein empties into the
femoral vein
Veins of the Right Lower Limb & Pelvis
Common iliac vein
Internal iliac vein
External iliac vein
Inguinal ligament
Femoral vein
Great saphenous vein (superficial)
Popliteal vein
Small saphenous vein
Fibular vein
Anterior tibial vein
Dorsalis pedis vein
Dorsal venous arch
Dorsal metatarsal veins
(a) Anterior view
Questions…?
What’s Next?
Lab: Blood & Blood Vessels
Mon Lecture: Finish material & Rev
Mon Lab: Lab Exam 4!
Wed Lecture: Lecture Exam 4!