By Taylor Tisch
Structure of arteries, veins, and capillaries
The walls of arteries and veins have three layers or tunics:
- An outer layer (tunica adventitia) of connective tissue with collagen fibers.
- A middle layer (tunica media) of circularly arranged smooth muscle and elastic fibers.
- An inner layer (tunica intima), consisting of a specialized simple squamous epithelium, often called the endothelium, that lines all blood vessels and the endocardium of the heart. The basement membrane, a subendothelial layer composed of connective tissue, supports the endothelium. Capillaries consist of an endothelium which is only one cell thick
- Blood Flow: Arteries- away from heart, Veins- towards the heart, Capillaries- where gas exchange occurs
Electrocardiogram (ECG) Test
- A normal ECG has 3 waves: P wave, QRS complex, and the T wave
- These waves represent the electrical activity that regulates the contraction/relaxation of the atria/ventricle
- Depolarization: the electrical activity that triggers contraction of the heart muscle
- Repolarization: begins just before the relaxation phase of cardiac muscle activity
Factors that influence Blood Pressure:
- Blood Volume: The higher the volume, the more pressure exerted on vessel walls
- Strength of <3: Higher the heartbeat, the higher the pressure
- Heart rate: The higher the rate, the higher the pressure
- Blood Thickness: Less than normal thickness decreases pressure
- Resistance to Blood Flow: affected by many factors
5 factors that influence blood pressure:
- Tobacco usage
- Cardiac Cycle: All the blood pumped from the ventricle in one minute
- Stroke Volume: All the blood pumped from the ventricle in one beat
- Pulse: A rhythmical throbbing of the arteries as blood is propelled through them.
- Normal Heart Sounds: the normal heart sound (sounds like “lub dub”.) Cause: Valves opening and closing and blood flowing
- Hematocrit test: indicates whether you have too few or too many red blood cells
- WBC Count: measures the number of white blood cells (WBCs).
- Platelet count: measures the number of platelets in your blood
This patient has Myocardial Infarction
Weight: 256The Cause: Smoker, Lack of Exercise, Unhealthy Diet, Note: Heart Condition runs in family
- EKG: Shows series of abnormalities Ex. Elevation between the T and S wave interval
- Pulse: Very fast rate
- Blood Pressure: Blood pressure dropped very low
- Stroke Volume: Decreased
- Cardiac Output: Decreased
- Heart Sounds: irregular (galloping sound)
- WBC Count: normal
- Hematocrit: normal
- Platelet Count: normal
Possible Solutions: Angioplasty – a surgical procedure used to open the arteries. Thrombolytic Therapy – drugs that destroy blood clots that may be used when angioplasty is not an option. Also stop smoking, excerise daily, and eat a healthy diet.
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