Open and Closed Circulatory Systems (Fig. 29.1)
Open circulatory systems
Closed circulatory systems
Arteries carry blood away from the heart, exchange of gases and nutrients occurs through thin-walled tiny capillaries, and veins return blood to the heart.
The Functions of Vertebrate Circulatory Systems
transports gases and nutrients
in temperature regulation (Fig. 29.2).
protects against injury and foreign microbes or toxins.
Architecture of the Vertebrate Circulatory System
endothelium covered by elastic fibers
Valves (Fig. 29.7)
The Lymphatic System: Recovering Lost Fluid (Fig. 29.8)
Lymphatic capillaries are blind-end tubes. (Fig. 29.9)
Lymph nodes with macrophages and lymphocytes,
Blood Plasma: The Blood's Fluid
fibrin. (Fig. 29.10)
Evolution of Vertebrate Circulatory Systems
A fish heart is a modified tube
consisting of a series of four chambers and the circulatory system forms a
single loop. (Fig. 29.12)
Amphibians and reptiles have lungs
loop circulatory system: (Fig. 29.13)
Mammals, birds, and crocodiles
Circulation Through the Heart (Fig. 29.14)
arteries and arterioles to capillaries. to venules and veins that merge to form the vena cava
How the Heart Contracts (Fig. 29.16)
This gives the "lub-dub" rhythm.
Monitoring the Heart's Performance
Heart Attack Symptoms and Warning Signs
A blood clot forms and totally stops blood flow in a coronary artery, resulting in a heart attack, which is also called an acute myocardial infarction (MI). Irreversible injury to the heart muscle usually occurs if medical help is not received promptly.
Warning signals of a heart attack:
Uncomfortable pressure, fullness, squeezing or pain in the center of the chest
lasting more than a few minutes.
* Pain spreading to the shoulders, neck or arms. The pain may be mild to intense. It may feel like pressure, tightness, burning, or heavy weight. It may be located in the chest, upper abdomen, neck, jaw, or inside the arms or shoulders.
* Chest discomfort with lightheadedness, fainting, sweating, nausea or shortness of breath.
* Anxiety, nervousness and/or cold, sweaty skin.
* Paleness or pallor.
* Increased or irregular heart rate.
* Feeling of impending doom.
Not all of these signs occur in every attack. Sometimes they go away and return. If some occur, get help fast.
Total Blood Cholesterol Levels: (mg/dl means milligrams per deciliter of blood)
than 200 mg/dl = Desirable
200 to 239 mg/dl = Borderline High
240 mg/dl and over = High Risk
HDL stands for high density lipoprotein. HDL is considered "good" or silent cholesterol because it seems to protect you from heart attack.
Levels: (milligrams per deciliter of blood = mg/dl)
Less than 35 mg/dl = High Risk
More than 60 mg/dl = Desirable
LDL stands for low density lipoprotein. This is the main carrier of harmful cholesterol in your blood. A high level of LDL means there is a higher risk of heart disease.
Levels: (milligrams per deciliter of blood = mg/dl)
Less than 130 mg/dl = Desirable
130 to 159 mg/dl = Borderline High
160 mg/dl or higher = High
Triglyceride levels - Most of your body fat comes in the form of triglycerides. High triglyceride levels can result from being overweight, drinking a lot of alcohol, or having diabetes or other disorders. High triglycerides are a risk factor for heart disease.
than 150 mg/dl = Normal
150 to 199 mg/dl = Borderline High
200 to 499 mg/dl = High
Greater than 500 mg/dl = Very High
Strokes are caused by an interference with the blood supply to the brain. There are two broad categories of stroke: those caused by a blockage of blood flow and those caused by bleeding.
What Are Warning Signs Of A Stroke?
Sudden weakness or numbness of the face, arm, or leg on one side of the body.
* Sudden dimness or loss of vision, particularly in one eye.
* Sudden difficulty speaking or trouble understanding speech.
* Sudden severe headache with no known cause.
* Unexplained dizziness, unsteadiness or sudden falls, especially with any of the other signs.
Sometimes the warning signs may last only a few moments and then disappear. These brief episodes, known as transient ischemic attacks or TIAs, are sometimes called "mini-strokes."
What Are The Treatable Risk Factors?
* High blood pressure. Also called hypertension, this is by far the most potent risk factor for stroke.
Some ways to reduce bp:
Maintain proper weight.
- Avoid drugs known to raise blood pressure.
- Cut down on salt.
- Eat fruits and vegetables to increase potassium in your diet.
- Exercise more.
Blood pressure guidelines
Normal < 120/80
Stage 1 hypertension 140-159/90-99
2 hypertension > 160/100
* Cigarette smoking. Cigarette smoking has been linked to the buildup of fatty substances in the carotid artery, the main neck artery supplying blood to the brain. Blockage of this artery is the leading cause of stroke in Americans. Also, nicotine raises blood pressure; carbon monoxide reduces the amount of oxygen your blood can carry to the brain; and cigarette smoke makes your blood thicker and more likely to clot.
* Heart disease. Common heart disorders such as coronary artery disease, valve defects, irregular heart beat, and enlargement of one of the heart's chambers can result in blood clots that may break loose and block vessels in or leading to the brain. The most common blood vessel disease, caused by the buildup of fatty deposits in the arteries, is called atherosclerosis. Your doctor will treat your heart disease and may also prescribe medication, such as aspirin, to help prevent the formation of clots. Your doctor may recommend surgery to clean out a clogged neck artery.
* Warning signs like TIA's or history of stroke.
* Diabetes causes destructive changes in the blood vessels throughout the body, including the brain.