2. Types of Blood Vessels
Arteries - vessels that transport blood
away from the heart
Veins - return blood back to the heart
Capillaries - microscopic blood vessels
that allow exchanges between blood
and tissues
3. Structure of a blood vessel
Tunica externa (adventitia) - outermost layer
made of loose connective tissue. Serves to
anchor, protect and prevent overstretching
Tunica media - middle layer composed of
smooth muscle; functions in dilation and
constriction of blood vessels
Tunica interna(intima) - innermost layer made
of endothelium (s.squamous epithelium)
4.
5.
6.
7.
8. Blood flow through tissues
From the heart blood flows into
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
Superior/ Inferior Vena Cava
Back to the heart
11. Capillaries
Microscopic vessels that connect
arterioles and venules
Walls consist of a single layer of simple
squamous epithelial cells that allow the
exchange of gases
Precapillary sphincters regulate blood
flow
Continuous/Fenestrated capillaries
12. Veins
Venules merge to form veins
Have 3 distinct layers; thinner walled
than arteries due to thin tunica interna
and media
Large lumens and posses valves
Varicose veins
Blood reservoir
13. Systemic Circulation
The aorta and its major branches
Arterial supply to neck and head
Arterial supply to upper extremities
Arterial supply to thorax
Arterial supply to abdomen
Arterial supply to pelvic region and
lower extremities
14. Systemic Veins
Venous drainage of the head and neck
Major tributaries of the inferior vena
cava
Venous drainage of the upper
extremities
Venous drainage of the lower
extremities
15. Hepatic Portal System
Routes blood from the stomach, spleen,
pancreas, small and large intestines to
the liver
Blood from these structures all drain
into the hepatic portal vein, then into
the liver
Blood is returned to the inferior vena
cava via the hepatic vein
16. Fetal Circulation
Placenta - site where exchange of
materials between fetus and mother occur
Umbilical arteries (2) - carry fetal blood
high in CO2 / low in O2 to the placenta
Umbilical vein - returns oxygenated blood
from the placenta to the fetus
17. Fetal Circulation
Ductus venosus - allows blood to bypass
the liver
Foramen ovale - opening in interatrial
septum allowing blood to bypass the lungs
Blood flows from r.atrium ->l.atrium
Ductus arteriosus - vessel connecting
pulmonary artery to the aorta
18. 1. superior vena cava
2. inferior vena cava
3. pulmonary veins
4. pulmonary trunk (p. artery, p. aorta)
5. systemic aorta
A. Great Vessels
19.
20. Branches of systemic aorta
1. from ascending aorta, right and left
coronary artery
2. from aortic arch, brachiocephalic
artery
a. right subclavian artery
(1) r. axillary artery
(a) r. brachial artery
1. r. ulnar artery
2. r. radial artery
21.
22.
23. 3. superficial and deep
palmar arches
(anastomoses)
(b) deep brachial artery
(c) posterior circumflex
(2) r. vertebral artery
Branches of systemic aorta
24. b. right common carotid artery
(a) r. external carotid artery
(b) r. internal carotid artery
c. (cat, not human) left common
carotid artery
(a) l. external carotid artery
(b) l. internal carotid artery
Branches of systemic aorta
25.
26.
27. 3. from aortic arch (human, not cat),
left common carotid artery
a. l. external carotid artery
b. l. internal carotid artery
Branches of systemic aorta
28. 4. from aortic arch, left subclavian artery
(cat and human)
a. l. axillary artery
(1) l. brachial artery
(a) l. ulnar artery
(b) l. radial artery
(c) superficial and deep palmar
arches (anastomoses)
Branches of systemic aorta
29. (2) deep brachial artery
(3) posterior circumflex
b. l. vertebral artery
5. from descending thoracic aorta
a. paired bronchial arteries
b. paired intercostal arteries
Branches of systemic aorta
30. 6. from abdominal aorta
a. celiac trunk
(1) splenic artery
(2) l. gastric artery
(3) hepatic artery
Branches of systemic aorta
31.
32.
33. b. superior mesenteric artery
c. paired renal arteries
d. paired gonadal arteries
e. paired lumbar arteries
f. inferior mesenteric artery
Branches of systemic aorta
34.
35. g. right and left common iliac arteries
(1) internal iliacs
(2) external iliacs->femorals->
popliteal->tibial->dorsalis pedis->
plantar arches
Branches of systemic aorta
36.
37.
38. C. Major veins
A. coronary circulation: coronary sinus
B. pulmonary circulation: pulmonary
veins
C. hepatic portal circulation: hepatic
portal vein drains
1. inferior mesenteric which drains
splenic vein
2. superior mesenteric vein
41. E. Systemic Circulation:
1. superior vena cava drains
a. azygos system
b. right and left brachiocephalic veins
c. internal jugular and subclavian vein
d. external jugular and axillary
e. cephalic vein (superficial) and brachial
vein (deep) which drains
radial, ulnar, median cubital and basilic
veins
42.
43.
44. 2. inferior vena cava drains
a. hepatic vein
b. phrenic vein
c. paired renal veins
d. paired gonadal veins
45.
46. e. paired common iliac veins which drain
(1) paired internal iliac veins
(2) paired external iliac veins which drain
(a) femoral veins which drain
1. popliteal veins which drain
a peroneal vein
b anterior and posterior
tibial veins
(b) great saphenous veins
51. Mechanisms of Exchange
Diffusion - major method used to
exchange substances such as O2, CO2,
glucose, and amino acids
Vesicular transport - endocytosis and
exocytosis of lipid-insoluble molecules
Bulk flow - involves filtration and
reabsorption
55. Blood Flow
Blood flow - is the amount of blood flowing
through a tissue in a given period of time
Velocity of blood flow is inversely related to
the diameter of the blood vessel
Blood flows most slowly in areas of greatest
width
56. Blood Pressure
Force that the blood exerts against the
walls of a blood vessels
Factors affecting BP include cardiac output,
blood volume, viscosity, resistance, and the
elasticity of the arteries
57. Cardiac Output
CO=Stroke volume X Heart Rate
Any factor that increases SV or HR will
increase blood pressure
58. Peripheral Resistance
Resistance to blood flow due to the force of
friction between vessel wall and blood
Resistance affected by blood viscosity,
vessel length and vessel radius
59. Sources affecting Resistance
Blood viscosity- how thick or thin the blood
is. Measured by hematocrit.
Vessel length- longer the vessel, the
greater the resistance, the greater the BP
Vessel radius- smaller the vessel the
greater the resistance
60. Blood Volume
Blood volume , Blood pressure
Blood volume, Blood pressure
Blood volume & blood pressure monitored
by the cardiovascular center in the medulla
(ANS), baroreceptors and chemoreceptors
and by hormonal regulation
61. Hormonal Regulation
of Blood Pressure
Renin- angiotensin pathway
Angiotensin II - powerful vasoconstrictor
thus raising resistance
Stimulates secretion of aldosterone from the
adrenal gland promoting sodium retention
ADH - antidiuretic hormone from the pituitary
causing the kidneys to reabsorb more water
62. Hormone lowering BP
ANP - atrial natriutic peptide
released by atrial cells promoting the
loss of salt and water in the urine ,
thus blood volume and causing
vasodilation which then blood
pressure
PTH - parathyroid hormone causes
vasodilation
63. Endothelin = potent vasoconstrictor
responds to low blood flow
NO (nitrous oxide) = powerful
vasodilator; balances endothelin and
dilates vessels in response to high blood
flow.
64. Normal Blood Pressure
Newborn = 90/55 mm Hg
Adults = 120/80 mm Hg
Old Age = 150/90
Systolic Pressure = peak pressure during
systole
Diastolic pressure = lowest pressure during
diastole (filling of ventricles)