Science Starter

• P. 999 Section 1 (11 vocabulary terms)

• Use p. 996 diagram to help with the worksheet

Blood Pressure

• Blood pressure is the force of blood against the walls of arteries. Blood pressure is recorded as two numbers—the systolic pressure (as the heart beats) over the diastolic pressure (as the heart relaxes between beats).

• Normal blood pressure is less than 120 mmHg systolic and less than 80 mmHg diastolic.

Blood Volume• Blood volume is a measurement of the volume, or

inhabited three-dimensional space, of blood that exists in a given person.

• Blood volume includes both red blood cells and plasma.

• If one loses too much blood because of a wound, dangerously low blood pressure can result. When one's blood pressure is too low, vital organs may receive inadequate amounts of oxygen

and nutrients.

Resistance

• Vascular resistance is a term used to define the resistance to flow that must be overcome to push blood through the circulatory system.

Factors that Affect Blood Flow• Vascular dementia: This common form of dementia

is an after effect of stroke or a series of strokes. • Strokes occur when blood supply to the brain is

interrupted by damaged vascular system. As a result of this the brain is deprived of oxygen and other nutrients.

• Patient suffers from thinking and memory related problems, confusion, dizziness, balancing problems, slurred speech etc.

Factors that Affect Blood Flow

• Raynaud's disease: This disease results in brief periods of vasospasm (narrowing of the arteries), there by affecting the blood flow.

• Arteries carry blood from the heart to the different parts of the human body. This disease affects blood supply to fingers and toes.

Factors that Affect Blood Flow

• Hypertrophic cardiomyopathy: Also referred to as HCM, this disorder results in thickening of heart muscles. This obstructs blood flow there by affecting normal functioning of the heart.

Factors that Affect Blood Flow• Atherosclerosis: This disease is one of the main causes of

death all over the world. • Arteries of the person suffering from this ailment are

hardened due to build up of fatty or mineral deposits (plaque).

• This leads to further complications like blood pressure and heart attack.

• Smoking, high fat diet, physical inactivity and stress can cause this disease.

Factors that Affect Blood Flow• Diabetes: Patients affected by diabetes suffer from

increase in blood sugar levels. • The body converts these sugars into triglycerides

(fatty substances). • Triglycerides mix with the blood making it thicker

and stickier.• As a result blood flow slows down, delaying oxygen

to various parts of the body.

Disease

• Hypertension is a common disorder that is defined as sustained elevation of systolic blood pressure (BP) > 160 mmHg and/or diastolic BP > 90 mmHg..• Ischemic heart disease (IHD) is a condition caused by reduction or cessation of the

blood supply to the myocardium. (The muscular tissue of the heart). This can result in angina (severe pain in the chest), heart attack, or death. – The most important cause of IHD is atherosclerosis. – Atherosclerosis= A disease of the arteries characterized by the deposition of

plaques of fatty material on their inner walls• Heart failure

Heart failure can be defined as the inability of the heart to maintain sufficient cardiac output to adequately perfuse the tissues for normal metabolism. It can be caused by conditions that damage heart or that demand increased work of the heart.

• ArrhythmiaAny deviation from the normal rhythm of the heart is known as an arrhythmia.

Sickle cell anemia

Sickle cell anemia is a disease passed down through families in which red blood cells form an abnormal crescent shape. (Red blood cells are normally shaped like a disc.)

What would be a problem with this?

Exercise

• The cardiovascular system serves five important functions during exercise:• 1) Delivers oxygen to working muscles

2) Oxygenates blood by returning it to the lungs3) Transports heat (a by-product of activity) from the core to the skin4) Delivers nutrients and fuel to active tissues5) Transports hormones

• Exercise places an increased demand on the cardiovascular system. • Oxygen demand by the muscles increases sharply. • Metabolic processes speed up and more waste is created. • More nutrients are used and body temperature rises. • To perform as efficiently as possible the cardiovascular system must

regulate these changes and meet the body’s increasing demands.