Diseases and Disorders of the Diseases and Disorders of the Circulatory SystemCirculatory System

HypertensionHypertension

• Hypertension means “high pressure”Hypertension means “high pressure”

• Blood pressure is the force that the blood exerts, driven Blood pressure is the force that the blood exerts, driven by the heart. This pressure has two values: by the heart. This pressure has two values: systolic systolic pressure pressure (when the ventricles contract) and (when the ventricles contract) and diastolic diastolic pressurepressure (when the heart is relaxed) (when the heart is relaxed)• Normal pressure is around 120 mm Hg (systolic) and 70-80 Normal pressure is around 120 mm Hg (systolic) and 70-80

mm Hg (diastolic)mm Hg (diastolic)• Hypertension occurs if the systolic pressure is over 140 mm Hg Hypertension occurs if the systolic pressure is over 140 mm Hg

or the diastolic pressure is over 100 mm Hgor the diastolic pressure is over 100 mm Hg

• Causes of high blood pressure include:Causes of high blood pressure include:• Stress, consumption of stimulants (tobacco, caffeine, etc), Stress, consumption of stimulants (tobacco, caffeine, etc),

excess weight, excess salt in the dietexcess weight, excess salt in the diet

Hypotension Hypotension

• Opposite of hypertension, when the blood pressure is very Opposite of hypertension, when the blood pressure is very lowlow• May cause dizziness and faintingMay cause dizziness and fainting

• Causes of hypotension include:Causes of hypotension include:• DehydrationDehydration

• MedicationMedication

• Sudden changes in postureSudden changes in posture

Varicose veinsVaricose veins

• Dilations in the veins, normally in the lower extremitiesDilations in the veins, normally in the lower extremities• Causes by a defect in the valves that prevent blood from Causes by a defect in the valves that prevent blood from

flowing back through the veinsflowing back through the veins

• Blood accumulates inside the veinsBlood accumulates inside the veins

AneurysmAneurysm

• The dilation of an artery, in which a kind of sac is formedThe dilation of an artery, in which a kind of sac is formed

• The danger of these blood accumulations depends on the The danger of these blood accumulations depends on the place where they are located, because they may burst at place where they are located, because they may burst at any momentany moment• An aneurysm is especially dangerous if it occurs in the aorta An aneurysm is especially dangerous if it occurs in the aorta

artery or in any artery in the brainartery or in any artery in the brain

Blood Vessel ObstructionBlood Vessel Obstruction

• Stroke Stroke – produced when the interruption of blood supply – produced when the interruption of blood supply affects a region of the brain, either due to a blood vessel affects a region of the brain, either due to a blood vessel breaking or becoming obstructed breaking or becoming obstructed

• Embolism – Embolism – caused by blood clots, which dislodge and caused by blood clots, which dislodge and begin to travel throughout the bloodstreambegin to travel throughout the bloodstream• These traveling blood clots may end up obstructing a blood These traveling blood clots may end up obstructing a blood

vessel, causing an embolismvessel, causing an embolism

• Myocardial infarction Myocardial infarction (heart attack) – a complete (heart attack) – a complete obstruction of the coronary arteriesobstruction of the coronary arteries• The heart is deprived of oxygen and nutrients, and its cells The heart is deprived of oxygen and nutrients, and its cells

begin to die if blood flow is not reestablishedbegin to die if blood flow is not reestablished

Hemorrhages (Bleeding)Hemorrhages (Bleeding)

• When blood flows out of the blood vessels in an uncontrolled When blood flows out of the blood vessels in an uncontrolled wayway• External hemorrhaging External hemorrhaging (most widely known) - Blood flows out (most widely known) - Blood flows out

from a broken blood vessel and leaves the bodyfrom a broken blood vessel and leaves the body• Internal hemorrhaging – Internal hemorrhaging – The blood flows out of the broken The blood flows out of the broken

blood vessel and stays inside the bodyblood vessel and stays inside the body

• The system that the body has to fight hemorrhaging is The system that the body has to fight hemorrhaging is clotting. clotting. • Platelets as well as Platelets as well as clotting factors clotting factors form fibrous structures that form fibrous structures that

cover the hole through which the blood leaks outcover the hole through which the blood leaks out

• Clotting disorders Clotting disorders (usually genetic) – Hemophilia is one of (usually genetic) – Hemophilia is one of the most widely known and is linked to the X chromosomethe most widely known and is linked to the X chromosome• Hemophilia is more common in men because women have another Hemophilia is more common in men because women have another

X chromosome to compensate for the defective oneX chromosome to compensate for the defective one