Circulatory system cont’d

Hypertension Cause: ◦Chronic high blood pressure (~140/90) ◦Damages heart and blood vessels ◦Can lead to coronary heart disease and stroke Treatments: ◦Diet ◦Exercise ◦Medication (vasodilators, diuretics, etc.)

Coronary heart disease Cause: ◦Build-up of plaque (over many years) in the coronary arteries ◦Plaque hardens and narrows arteries ◦Full blockage can cause angina or a heart attack Treatments: ◦Diet/exercise ◦Medication ◦Surgery

Stroke Cause: ◦Loss of brain function due to a disturbance in blood supply to the brain ◦Can cause temporary or permanent damage or even death ◦Symptoms = loss of speech, understanding and memory, facial drooping and vision impairment Treatment: ◦None ◦Prevention with medication is possible

Heart attack Cause: ◦Plaque-blocked coronary artery leads to heart muscle injury/death ◦Heart is weakened and fails to move blood as appropriate Treatment: ◦Medication (some claim daily Aspirin dose is preventative) ◦Surgery to clear arteries

Technology Bypass surgery ◦Used if vessels to your heart are narrowed/damaged ◦Vein transplanted from extremity to ‘bypass’ damaged/blocked vessels and supply your heart with enough O 2 Pacemaker ◦Used to treat arrhythmias ◦Sets pace of contraction impulse ◦New models can record data that can be downloaded

Technology Cardiac catheterization ◦Also called angioplasty ◦Narrowed or damaged arteries are reopened/held open to allow proper flow ◦Wire mesh, or stent, implanted

Comparative anatomy

Insects Tubular heart circulates hemolymph around organs Hemolymph returns to heart through pores OPEN CIRCULATION! Pumping is facilitated by muscle contractions and usually during movement

Earthworm Pseudohearts/auxillary hearts circulate blood through 2 main vessels CLOSED CIRCULATION! Primary function of circulatory system is delivery of digested nutrients (gas exchange occurs through skin)

Fish Two-chambered heart pumps blood to gills and body (in that order) IS THIS CLOSED OR OPEN CIRCULATION?

Frogs/amphibians IS THIS CLOSED OR OPEN CIRCULATION?

Try this… Pg. 340, #1, 3 – 4 Pg. 344, #1, 7 - 8