What is the Cardiovascular System
Includes heart and blood vessels, brings nutrients to cells and helps get rid of wastes, blood is refreshed in the lung, kidneys, intestine and liver, lymphatic vessels help this system by collecting excess fluid surrounding tissues and returning it to th
Functions of the Cardiovascular system?
1. Generate blood pressure, 2. transport blood, 3. exchange of nutrients and wastes at the capillaries, 4. regulate blood flow as needed
Main pathway of blood in the body
Heart-Arteries-Arterioles-Capillaries-Venules-Veins-Back to the Heart...
Arteries
Carry blood away from the heart: Walls have three layers: Thin Inner Epithelium (Endothelium), Thick Smooth Muscle Layer (and elastic tissue), Outer Connective Tissue
Arterioles
Small arteries that regulate blood pressure
Capillaries
Microscopic vessels between arterioles and venules, made of one layer of epithelial tissue, form beds of vessels where exchange with body cells occurs, combined large surface area.
Venules
Small veins that receive blood from the capillaries and take blood to veins.
Veins
Carry blood toward the heart, veins that carry blood against gravity have valves to keep blood flowing toward the heart.
Venules and Vein Wall Layers
Thin Inner Epithelium, Thick Smooth Muscle Layer, Outer Connective Tissue
Anatomy of the Heart
Large, muscular organ consisting of mostly cardiac tissue called the Myocardium; surrounded by a sac called the Pericardium; consists of 2 sides, right and left, separated by a Septum; consists of 4 chambers: 2 atria and 2 ventricles; 2 sets of valves: se
How does blood flow through the heart?
Inferior and Superior Vena Cava (1) dump blood into the right atrium (2), Right ventricle (3), 2 Pulmonary Arteries (4) that lead to the lungs (5) where blood becomes oxygenated, Pulmonary Veins (6) bring blood from the lungs back to the left atrium (7),
How do structure of the vessels and heart match their functions?
The left ventricle is much more muscular than the right ventricle because it must pump blood to the entire body; the arteries are more muscular than veins to withstand the higher pressure exerted on them; the veins have a thinner wall and a larger center
How does the heartbeat occur?
During the Systole, the atria contract together followed by the ventricles contracting together; This is followed by the Diastole, a rest phase, when the chambers relax; This cardiac cycle, or heartbeat, occurs 70 times/minute on average.
Systole
Contraction period of the heart during the cardiac cycle.
Diastole
Relaxation of a heart chamber during the cardiac cycle.
How is the heartbeat controlled? Internal Control
Internal Control: The SA node in the right atrium initiates the hartbeat and causes the atra to contract; this impulse reaches the AV node, also in the right atrium, to send a signal down the AV bundle and Purkinje fibers that causes ventricular contracti
SA Node
(sinoatrial node) Small region of neuromuscular tissue that initiates the heartbeat; also called the pacemaker.
AV Node
(atrioventricular node) Small region of neuromuscular tissue that transmits impulses received from the sinoatrial node to the ventricles.
Intercalated Disks
Region that holds adjacent cardiac muscle cells together; disks appear as dense bands at right angles to the muscle striations.
How is the heartbeat controlled? External Control
Heartbeat is also controlled by a cardiac center in the brain and hormones such as epinephrine and norepinephrine
What is an electrocardiogram (ECG)
It is a record of the electrical changes in the heart muscle during a cardiac cycle; The atria produce an electrical current, called the P wave, when stimulated by the SA node; the contraction of the ventricles is the QRS complex; the recovery of the vent
What is blood pressure?
It is the pressure against a blood vessel wall, usually measured in an artery of the arm; the highest pressure, called the systolic pressure, is during blood ejection from the heart; the lowest pressure, the diastolic pressure, occurs when the ventricles
How is blood pressure categorized?
Hypotension (-95/-50), Normal (-120/-80), Pre-hypertension (120-139/80-89), Stage 1 Hypertension (140-159/90-99), Stage 2 Hypertension (+160/+100), Hypertensive Crisis (emergency) (+180/+110)
What is important about blood flow?
Blood flow is under the highest pressure in the arteries but remember the thick, muscular walls; Blood flow is slower in the capillaries which is important to allow time for exchange between cells; Blood pressure is minimal in the veins and venules but bl
If blood pressure is so low in the veins, why does the blood flow increase?
They have help; 1. Skeletal muscle contraction, 2. Breathing, 3. Valves
What are the 2 cardiovascular pathways in the body?
Pulmonary Circuit, Systemic Circuit
Pulmonary Circuit (Cardiovascular pathway)
The right side of the heart that brings blood from the body to the heart and the lungs.
Systemic Circuit (Cardiovascular pathway)
The left side of the heart that brings blood to the entire body to deliver nutrients and rid it of wastes.
Know Veins
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The heart's blood supply: Coronary Circulation
There are small coronary arteries that supply the heart; they are separate from the systemic and pulmonary pathways of the body.
Hepatic Portal System?
System that brings amino acid and glucose-rich blood from the digestive tract to the liver; the liver synthesizes blood proteins and stores the glucose as glycogen; the liver also plays a role in purifying blood from the digestive tract; Finally, the bloo
Exchange at the Capillaries
Lymphatic capillary beds lie alongside capillary beds; when lymphatic capillaries take up excess fluid it becomes lymph; lymph returns to the cardiovascular veins int he chest; Pre-capillary sphincters can shut down a blood capillary, and blood then flows
Cardiovascular Disease (CVD)
most common cause of death in the western world
Disorders of the blood vessels
Hypertension/High blood pressure; Atherosclerosis; Stroke; Heart Attack; Aneurysm.
Hypertension
High blood pressure results when blood moves through vessels at a rate higher than normal, often due to arterial plaque; 140/90 mmHg; Silent killer because there are few symptoms; Can lead to heart attach, stroke or kidney failure.
Atherosclerosis
Build up of plaque in blood vessels; Plaque that is stationary is called a thrombus, and an embolus when it detaches and can move to distant sites; It is associated with a stroke, heart attack and aneurysm.
Stroke
Also known as the cerebrovascular accident (CVA); usually occurs when cranial artery is blocked or bursts; part of the brain dies due to lack of oxygen; symptoms may include numbness of hands/face, difficulty speaking, and inability to see in one eye.
FAST
Face, Arms, Speech, Time
Heart Attack
Also known as a myocardial infarction (MI); part of the heart dies due to lack of oxygen; can begin with angina pectoris, a pain that radiates down the left arm due to the blockage of the coronary artery.
Aneurysm
Ballooning of a blood vessel; Atherosclerosis and hypertension can weaken a vessel and cause ballooning; the most commonly affected is the abdominal artery or arteries leading to the brain.
How are disorders of the blood vessels treated?
Dissolving blood clots: t-PA is a drug that dissolves clots (tissue plasminogen activator); Treating clogged arteries: bypass surgery, usually a vein from the leg is taken and used to bypass a clogged artery, stents, wire mesh cylinder inserted into a clo
Disorders of the heart and its treatment
Disorders: heart failure is when the heart no longer pumps properly, treatments: left ventricular assist device (LVAD), heart transplant either natural or artificial.
Cardiovascular Disease Prevention
Preventable risk factors include: use of tobacco products, drug and alcohol abuse, obesity and a sedentary lifestyle, poor diet, stress, poor dental hygiene.