Blood Vessels

1
Blood Vessels
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
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
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

9
Arteries

• Elastic (conducting) arteries
• Larger arteries
• Muscular ( distributing) arteries
• Medium arterties
• Arterioles
• Tiny , tiny arteries
• Metarteriole

10
(No Transcript)
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 -gtl.atrium
• Ductus arteriosus - vessel connecting pulmonary
  artery to the aorta

18
A. Great Vessels

• 1. superior vena cava 2. inferior vena cava 3.
  pulmonary veins 4. pulmonary trunk (p. artery,
  p. aorta) 5. systemic aorta

19
(No Transcript)
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
(No Transcript)
22
(No Transcript)
23
Branches of systemic aorta

• 3. superficial and deep
  palmar arches (anastomoses)
  (b) deep brachial artery (c)
  posterior circumflex (2) r. vertebral
  artery

24
Branches of systemic aorta

• 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

25
(No Transcript)
26
(No Transcript)
27
Branches of systemic aorta

• 3. from aortic arch (human, not cat),
  left common carotid artery a. l. external
  carotid artery b. l. internal carotid artery

28
Branches of systemic aorta

• 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)

29
Branches of systemic aorta

• (2) deep brachial artery (3)
  posterior circumflex b. l. vertebral artery
• 5. from descending thoracic aorta a. paired
  bronchial arteries b. paired intercostal
  arteries

30
Branches of systemic aorta

• 6. from abdominal aorta a. celiac trunk (1)
  splenic artery (2) l. gastric artery (3)
  hepatic artery

31
(No Transcript)
32
(No Transcript)
33
Branches of systemic aorta

• b. superior mesenteric artery c. paired renal
  arteries d. paired gonadal arteries e. paired
  lumbar arteries f. inferior mesenteric artery

34
(No Transcript)
35
Branches of systemic aorta

• g. right and left common iliac arteries (1)
  internal iliacs (2) external iliacs-gtfemorals-gt
  popliteal-gttibial-gtdorsalis pedis-gt
  plantar arches

36
(No Transcript)
37
(No Transcript)
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

39
(No Transcript)
40
D. Cranial Circulation

• cranial venous sinuses

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
(No Transcript)
43
(No Transcript)
44

• 2. inferior vena cava drains a. hepatic vein
  b. phrenic vein c. paired renal veins d.
  paired gonadal veins

45
(No Transcript)
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

47
(No Transcript)
48
(No Transcript)
49
Capillary Exchange
50
(No Transcript)
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

52
Arteries Veins

• Pressures promoting filtration
• Blood hydrostatic pressure
• Interstitial fluid osmotic pressure

• Pressures promoting reabsorption
• Blood colloid osmotic pressure
• Interstitial fluid hydrostatic pressure

53
Physiology of Circulation
54
Important Terms

• Blood Flow
• Blood pressure
• Resistance

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

• COStroke 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)

65
(No Transcript)
66
(No Transcript)
67
(No Transcript)
68
(No Transcript)
69
(No Transcript)
70
(No Transcript)