12.3 CIRCULATORY SYSTEM DISORDERS

Arteriosclerosis• Wall of arteries thicken, lose elasticity

• Atherosclerosis: plaque builds up (fats, calcium, fibrous tissues)

• Narrow artery blood pressure increases

• Lead to:• angina (chest pain)

• blood clots

• shortness of breath

• heart attack

• heart failure

Arteriosclerosis

• Prevention: healthy lifestyle

• Treatments: aspirin, urokinase, t-PA (for clots), angioplasty, coronary bypass

Aneurysm• A bulge in an artery

• Weakened area of the arterial wall

• Blood pressure causes aneurysm grow larger over time

• Bursts internal bleeding can be fatal

• Most occur in aorta

• Treatments: surgery – removed damaged portion and replace with a patch or graft (synthetic material)

A coloured MRI scan

shows an

aneurysm (bulging) in

one of the arteries of

the neck. The scan

was done to determine

the cause of the

patient’s dizziness.

Heart Valve Diseases• Regurgitation: • valve not close properly

• blood flows backward

• Stenosis: • valve opening narrowed

(thickening/scarring)

• inhibit blood flow

• Mitral valve prolapse: • one/both valve flaps bulges back into atrium

• prevent tight seal

Heart Valve Diseases• Causes: • ageing, previous heart attack,

infection

• Treatment: • repair valve

• replace with human/animal/metal/plastic/ synthetic alternative

Arrthythmia

• Problem with speed or rhythm of heartbeat

• insufficient blood flow to brain/other organs

• Treatment:• Medication

• Implant artificial pacemaker

• Video (3:06)

Congenital heart defects

• From birth

• problems with septum, valves, blood vessels

• Diagnose: CT or MRI scans

• Treatment: surgery to repair or reduce damage

Stroke

• Ischemic stroke: clot blocks blood flow to brain

• Hemorrhagic stroke: blood vessel in brain bursts

• kill brain cells permanent damage

• Treatment • Immediate to be effective

• Surgery

• Non-surgical procedures (Clot-busters)

Disorders of blood

Anemia

• Fewer than normal RBC

• Causes: blood loss or RBC not enough hemoglobin

• Symptoms: dizziness, fatigue, shortness of breath, headache, cold extremities

• Treatment: dietary supplements

Hemophilia

• Inherited disorder (genetics)

• Missing clotting proteins (eg factor VIII)

• blood does not clot properly

• Treatment:• Factor VIII injection

• Lifestyle changes (avoid injury and internal bleeding)

leukemia

• Cancer of the WBC

• Myeloid leukemia: • too many immature leukocytes (cannot fight infection)

• Lymphoid leukemia: • too many lymphocytes that cannot preform their immunity

role

• Both acute and fatal or chronic

• Treatment: blood transfusion, chemotherapy, bone marrow transplant

(A) Normal blood cells. (B) Blood from a patient

with leukemia. Notice the increased number of

white blood cells (shown in purple).

Diagnosing disorders• coronary angiography: maps the coronary (heart) arteries

• echocardiogram: cause of a stroke and possible blood clots

• exercise electrocardiogram: cause of chest pain, irregular heartbeats, dizziness, or fatigue

• Holter monitor: cause of rhythm disturbances

• event monitor: cause of a problem while symptoms are present

• cardiac catheterization: takes internal X rays of the heart to investigate problems

Treatment: Angioplasty• For arteriosclerosis

• Insert tube into clogged artery

• Inflate a tiny balloon force artery to open

• Insert a vascular stent (a wire-mesh tube) to keep vessel open

• Video (1:30)

Treatment: Coronary Bypass• Use a section of healthy artery/vein from other body parts

• Create a new pathway (blood flows around a blockage)

• Double, triple or quadruple bypass depends on number of blockage

• Video (1:38)

Treatment: organ transplants

• >1800 Canadians waiting for organ transplant

• Lungs, liver, kidney, pancreas, corneas, stomach, heart valves, bone, skin, heart

• Many die before a suitable organ is available

A surgeon holds a human heart

during a heart transplant operation.

Treatment: xenotransplants

• Use non-human compatible species

• Organ is called a graft

• Recipient may reject organ

• drugs

• Health, safety, legal, ethical, regulatory issue

Treatment: artificial hearts

• Made of titanium and plastic

• External battery constantly and wirelessly recharge an internal battery

This artificial heart is currently used as a

temporary replacement for patients

awaiting a human heart transplant due to

a condition known as biventricular failure.

Treatment: nanotechnology• Use microscopic structures to detect changes in cells and

molecules

• Biomarker: molecule that points to development of a disease

• Eg. Enzymes produced by cancer cells

• Microcontainers (nanovalves): delivers drugs only when encounter the biomarker

Homework

• p.503#1-5, 7, 9, 10,12-14