Anatomy

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• Anatomy Physiology
• BLOOD VESSELS AND CIRCULATION
• Chapter 13
• By
• Dr. Jay Shahed

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BLOOD VESSELS

• Kinds
• Arteries -
• Carries blood away from the heart
• Veins -
• Carries blood toward the heart
• Capillaries -
• Carries blood from the Arterioles to the Venules

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Arteries

• Structure
• Tunica Intima ( Interna-)
• Inner layer of endothelial cells
• Tunica Media-
• Smooth muscle, thick in arteries important in
  blood pressure regulation
• Tunica Adventitia (Externa-)
• Thin outer layer of elastic tissue

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Functions

• Distribution of nutrients, gases, etc.,
• Movement of blood under high pressure
• Assist in maintaining the arterial blood pressure

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Veins

• Structure
• Tunica Interna
• Inner layer
• Contains valves that prevents the retrograde
  movement of blood
• Tunica Media
• Smooth muscle, thin in veins
• Tunica Externa
• Heavy layer in many veins

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Functions

• Collect blood from the tissues and returns it to
  the heart
• Has low pressure

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Capillaries

• Microscopic vessels that connects the Arterioles
  with the Venules
• It consist of only one layer that is Tunica
  Interna
• Functions
• Serves as exchange vessels for nutrients, wastes,
  and fluids between the blood and cells.

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• DISORDERS
• OF
• BLOOD VESSELS

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ARTERIES

• Arteriosclerosis-
• Hardening of the arteries due to different
  factors including Calcium deposits and
  Cholesterol
• Reduces flow of blood to the tissues, possibly
  causing Ischemia that may progress to Necrosis or
  gangrene

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• Atherosclerosis-
• Disorder in which lipids build up and other
  matter blocks arteries
• May be corrected by
• Vasodilators (Vessel-relaxing drugs)
• Angioplasty (Mechanical widening of vessels)
• Surgical Bypass replacement

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• Aneurysm-
• Abnormal bulging of arterial wall
• Aneurysms promote formation of thrombi that may
  obstruct vital tissues
• Aneurysms may burst, resulting in life
  threatening hemorrhaging

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Strokes

• CerebroVascular Accident (CVA)
• Ischemia of brain tissue caused by embolism or
  hemorrhage
• Transient Ischemic Attach
• Temporary stroke ( Less that 24 HRS)

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Veins

• Varicose Veins (Varices)-
• Damaged valves that causes enlarged bulge were
  blood pools by the valves
• Hemorrhoids
• Are varicose veins in the rectum
• Treatments
• Supporting affected veins( Stockings)
• Surgical removal of veins

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• Phlebitis
• Inflammation of a vein
• Thrombophlebitis
• Vein inflammation due to clot (thrombus)
• pulmonary embolism
• Fatal blood clot in the lung

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Type of Circulations

• SYSTEMIC BLOOD CIRCULATION
• Blood flows from the heart through the Aorta to
  the Arteries to the Arterioles to the Capillaries
  ( Nutrition and gas exchange) to the Venules to
  the Veins back to the Heart through the Inferior
  and Superior Vena Cava in a circuit or circular
  pattern

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• Pulmonary Circulation
• Carries blood to and from the lungs
• Pulmonary Arteries deliver Deoxygenated blood to
  the lungs for gas exchange through the
  Capillaries.
• Then Pulmonary Veins will deliver Oxygenated
  blood to Left Atrium .

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• Hepatic Portal Circulation
• Unique blood route through the liver that returns
  necessary and unnecessary nutrient back to the
  blood to be used or wasted.
• Hepatic Portal Veins exists between two capillary
  beds
• Assists with homeostasis of blood Glucose levels

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• Fetal circulation
• Refers to circulation before birth
• Modifications required for fetus to efficiently
  secure Oxygen and nutrients from the maternal
  blood
• Blood flows from the Placenta to the Umbilical
  Vein through the Ductus Venosus in the Liver to
  the Fetal heart through the Foramen Ovale to the
  Umbilical Arteries back to the Placenta.

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BLOOD PRESSURE

• Definition
• Is the push of blood against the walls of the
  blood vessels
• Highest in arteries
• Lowest in veins
• Blood pressure varies within normal range from
  time to time.

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Physiological factors that affect blood pressure

• Blood pressure gradient
• Blood flow only from the area where pressure is
  higher to lower.
• Blood volume
• 5 liters
• Stroke volume ( Heartbeat)
• Amount of blood pumped per one beat
• Blood Viscosity
• The thickness of the blood.

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• Blood resistance
• The resistance that is produced against the
  normal blood flow gradient in the blood vessel.
• Lumen Diameter
• Of the blood Vessel

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PULSE

• Definition
• Section of the artery that passes close to the
  skin surface that alternate expansion and recoil
  of the blood vessel wall caused by the turbulence
  of the blood flow which can be easily felt.

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CIRCULATORY SHOCK

• Definition
• Failure of the circulatory system to deliver
  Oxygen to the tissues adequately.

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Types of Shock

• Cardiogenic Shock-
• Caused by heart failure
• Hypovolemic Shock-( Hemorrhagic)
• Internal or external bleeding that leads to a
  drop in the blood volume causes blood pressure
  (and blood flow) to drop
• Neurogenic Shock- ( Psychological )
• Nerve condition that causes the relaxation and
  dilatation of blood vessels and thus reduces
  blood flow

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• Anaphylactic Shock
• Caused by a severe allergic reaction
  characterized by blood vessel dilation
• Septic Shock
• Results from complications of septicemia ( blood
  toxins or infections )

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