Open and Closed Circulatory Systems (Fig. 29.1)
Gastrovascular cavity
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
removes
wastes
transports hormones
functions
in temperature regulation (Fig. 29.2).
protects against injury and foreign microbes or toxins.
Architecture of the Vertebrate Circulatory System
Cardiovascular system.
Three layers from inside to outside Fig. 29.4 and Fig 29.6
endothelium covered by elastic fibers
smooth muscle
connective tissue.
Arteries.
Arterioles
Capillaries. (Fig. 29.3) (Fig. 29.5)
Venules
Veins
Valves (Fig. 29.7)
The Lymphatic System: Recovering Lost Fluid (Fig. 29.8)
Lymphatic capillaries are blind-end tubes. (Fig. 29.9)
Lymph
Lymph nodes with macrophages and lymphocytes,
Blood Plasma: The Blood's Fluid
Blood Cells (Fig. 29.11)
Blood
composition
hemoglobin
leukocytes
platelets
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
double
loop circulatory system: (Fig. 29.13)
Mammals, birds, and crocodiles
Endothermy
Circulation Through the Heart (Fig. 29.14)
pulmonary veins
left atrium
left ventricle.
aorta
body.
arteries and arterioles to capillaries. to venules and veins
that merge to form the vena cava
right atrium.
right ventricle.
pulmonary arteries
lungs.
How the Heart Contracts (Fig. 29.16)
This
gives the "lub-dub" rhythm.
Monitoring the Heart's Performance
stethoscope
murmur.
Arterial blood pressure can be
measured. (Fig. 29.15)
electrocardiogram. (Image
and image)
Cardiovascular Diseases
Angina pectoris
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.
Atherosclerosis
(Image and image)
Total Blood Cholesterol Levels: (mg/dl means
milligrams per deciliter of blood)
Less
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.
HDL-Cholesterol
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.
LDL-Cholesterol
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.
Less
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
Arteriosclerosis
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.
- Medication
Blood pressure guidelines
Normal
< 120/80
Prehypertension
120-139/80-89
Stage
1 hypertension 140-159/90-99
Stage
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.