Heart and Blood Vessels

Sinoatrial node

"cardiac pacemaker." A small mass of cardiac muscle cells located near the junction of the right atrium and the superior vena cava. Stimulus that starts a heartbeat begins here.

In what ways do the veins pump blood back to the heart?

1. contractions of the skeletal muscles 2. one way valves permit only one way blood flow 3. movements associated with breathing

Precapillary Sphincter

A band of smooth muscle right where the arteriole joins the capillary. Serve as gates that control blood flow into individual capillaries.

Cardiac Conduction System

A group of specialized cardiac muscle cells that initiate and distribute electrical impulses throughout the heart. Stimulate the heart to contract in an orderly sequence.

Pericardium

A tough fibrous sac that the heart is inside of. It protects the heart, anchors it to surrounding structures, and prevents it from overfilling with blood.

Arrhythmia

Abnormality of the rhythm or rate of the heartbeat.

Left ventricle

After passing through the left atrium, blood passes through here. Most muscular chamber because does more work than any other chamber and pumps blood into the aorta.

Right ventricle

After passing through the right atrium, blood passes through here next. More muscular than the right atrium because it pumps blood at considerable pressure through a second valve and into artery leading to lungs.

What's so good about the pores and slits in a capillary?

Allow for blood to exchange oxygen, carbon dioxide, nutrients, and waste products.

Xenotransplant

An organ from another species. Still in the research stage, not approved for human use.

_ blood pressure is held constant, and local blood flows are _ to meet local requirements.

Arterial; adjusted

The first step of the cardiac cycle

Atrial systole- -both atrias contract -forces blood into ventricles -Av valves open -semilunar valves are closed

Aneurysm

Ballooning of the artery wall when endothelium becomes damaged and blood seeps through the injured area and goes between the two outer layers, splitting them apart. Very serious

Atrioventricular node

Between atria and ventricles. Electrical impulse goes from atria to here. Smaller muscle fibers= slight delay that gives the atria time to contract and empty their blood into the ventricles before the ventricles contract.

Embolism

Blockage of a blood vessel by material floating in the blood stream

Left atrium

Blood returning from the lungs to the heart enters here.

Right atrium

Blood that is returning to the heart from the body enters the heart here.

Where are baroreceptors located?

Carotid arteries and aorta

Angina

Chest pains from narrowed arteries and decreased blood flow to heart

Cardiac veins

Collect the blood from the capillaries in the heart muscle and channel it back to the right atrium.

Stroke

Damage to part of the brain caused by impairment of blood supply to brain

The third step of the cardiac cycle

Diastole- -Both atria and ventricles are relaxed -pressure falls

Cardiac muscle

Doesn't connect to bone. Pumps ceaselessly in a squeezing motion to propel blood through blood vessels.

Capillary Beds

Extensive networks of capillaries that can be found in all areas of the body.

Atrioventricular bundle

Group of conducting fibers in the septum between the two ventricles. , Specialized muscle fibers connecting the atria with the ventricles and transmitting impulses between them

Myocardial Infarction

Heart Attack!! Sudden death of an area of heart tissue due to lack of oxygen

Systemic circuit

Heart is pumping blood through the rest of the body to cells

Heart failure

Heart muscles become damaged and heart becomes weaker and less efficient at pumping blood

Pulmonary Circuit

Heart pumping blood through the lungs

Congestive heart failure

Heart pumps less blood, so blood backs up in veins, pressure in veins and capillaries rise, causes more fluid than usual to filter out of capillaries and into interstitial fluid. build up of interstitial fluid

Lumen

Hollow interior of the vessel

Endocardium

Inner most layer of the heart. A thin endothelial later resting on a layer of connective tissue.

Why does the left ventricle have to be more muscular than the other chambers?

It must generate pressures higher than aortic blood pressure in order to pump blood into the aorta

What role does the lymphatic system play in the vascular system?

It removes excess fluid

Arteries

Large, muscular, thick walled tubes that transport blood away from the heart.

Endothelium

Layer of flattened squamous epithelial cells. A continuation of the lining of the heart. Flattened cells fit closely together, creating a slick surface that decreases friction and helps smooth blood flow.

Bicuspid or mitral valve

Left AV valve that has two flaps

Hypotension

Low blood pressure. Usually only a problem if it falls low enough to reduce blood flow to brain.

Myocardium

Middle layer of the heart. A thick layer consisting mainly of cardiac muscle that forms the bulk of the heart. This is what contracts during a heart beat.

Papillary muscles

Muscular extensions of the ventricle walls that help the chordae tendineae prevent the valves from opening backward into the atria when the muscles contract.

Septum

Muscular partition that separates the right and left sides of the heart.

What are the arteries like near the heart and farther away from the heart?

Near the heart, they are larger with thicker muscle so they can withstand the high pressures generated by the heart. The farther away from the heart, the smaller the arteries are.

Varicose Veins

Permanently swollen veins that look twisted and bumpy from pooled blood. People who spend a lot of time on their feet.

Semilunar valves

Pulmonary and aortic valves. Prevent back flow into the ventricles from the main arteries leaving the heart when the heart relaxes. Each has three pocketlike flaps.

Baroreceptors

Regions in large arteries that regulate arterial blood pressure

Vasodilation

Relaxation of vascular smooth muscle. Increases their diameter and so increases blow flow into capillaries.

Pericardial cavity

Separates the pericardium from the heart. Contains a film of lubricating fluid that reduces friction and allows the heart and the pericardium to glide smoothly against each other when the heart contracts.

Venules

Small veins

What is the middle layer of an artery made out of?

Smooth muscle with elastic fibers. Thickest layer. Elastic in large/medium arteries so they can stretch to accommodate blood.

Which kind of nerves stimulate the heart and cause it to beat FASTER?

Sympathetic. also controls blood vessel diameters.

Isolated systolic hypertension

Systolic pressure registers at above normal levels and diastolic pressure remains normal.

Why do heart attacks cause permanent damage?

The body can't replace cardiac muscle cells

Why is the recovery rate of a stroke poor?

The body doesn't grow new nerve cells to replace damaged ones

Why do the lower part of the ventricles contract before the upper part?

The electrical impulse travels down the septum to the lower portion of the ventricles first and then spreads rapidly upward

Cardiac cycle

The entire sequence of contraction and relaxation

Blood pressure

The force that blood exerts on the wall of a blood vessel as a result of the pumping action of the heart.

Systolic pressure

The highest pressure of the cycle. The pressure reached during ventricular systole when the ventricles contract to eject blood from the heart.

Sphygmomanometer

The inflatable cuff device placed over the brachial artery in upper arm and connected to a pressure-measuring device

Diastolic pressure

The lowest pressure that occurs during ventricular diastole when the ventricles relax.

Where is the cardiovascular center located in the brain?

The medulla oblongata

Epicardium

The outermost layer of the heart. A thin later of epithelial and connective tissue.

Systole

The period of contraction

Diastole

The period of relaxation

Why don't veins need as much wall strength as arteries?

The pressure in veins, since they are far from the heart, is only a small fraction of what it is in arteries.

Tricuspid valve

The right AV valve that has three flexible flaps.

Capillaries

The smallest blood vessels. Thin walls. Act as a strainer: They permit selective exchange of substances with the interstitial fluid. The only blood vessels that can exchange with interstitial fluid.

Arterioles

The smallest of arteries. Lack the outermost layer of connective tissue, and their smooth muscle isn't as thick.

Atria (atrium)

The two chambers on top.

The second step of the cardiac cycle

The ventricular systole- -Contraction spreads to ventricles, both contract at same time -AV valves close -semilunar valves open -Blood is ejected to pulmonary trunk and aorta

What do the arterioles do that large arteries don't?

They help regulate the amount of blood that flows to each capillary. They do this by contracting or relaxing the smooth muscle.

What's the problem with artificial hearts?

They're only temporary solution until you can find a real heart.

What's the outer layer of a large/medium sized artery made out of?

Tough supportive layer of connective tissue, mostly collagen. Protects vessels from injury by anchoring them to surrounding tissues.

Murmurs

Unusual heart sounds caused by disturbed blood flow

Veins

Walls contain three layers of tissue but the outer two layers are much thinner than that of arteries. Veins also have a larger diameter lumen that allows them to stretch to accommodate large volumes of blood at low pressures. 2/3 of all your blood is stored in your veins.

How to the baroreceptors help regulate arterial blood pressure?

When blood pressure rises, the baroreceptors stretch which causes them to send signals via nerves to the cardiovascular center of the brain. This center sends signals to the heart and blood vessels to lower heart rate. Arterioles vasodilate (increase in diameter)

Pulse

Where you can feel this cycle of rapid expansion and recoil in the wall of an artery when its located close to the skin's surface

Cardiac output

amount of blood that the heart pumps into the aorta each minute. calculated by multiplying heart rate by stroke volume (volume of blood pumped out with each heartbeat)

pulmonary embolism

blocks an artery flowing to the lungs= chest pain and shortness of breath

Cardiac embolism

can cause heart attack

Hypertension

high blood pressure

cerebral embolism

impairs circulation to brain

the suffix "itis" refers to

inflammation of a certain part of the heart

Atrioventricular valves

located between the atria and their corresponding ventricle prevent blood from flowing back into the atria when the ventricles contract. Thin connective tissue flaps (cusps) that project into ventricles.

What is blood pressure recorded as?

mm Hg (milimeters of mercury)

Which nerves cause it to beat slower?

parasympathetic

Electrocardiogram (ECG)

record of electrical impulses in the cardiac conduction system. Electrodes placed on skin at chest wrist and ankles. Electrodes transmit the hearts electrical impulses that are recorded as a continuous line on a screen

Homeostatic regulation of the cardiovascular system centers on maintaining what?

relatively constant arterial blood pressure

Purkinje fibers

smaller fibers that carry the impulse to all cells in the myocardium of the ventricles

Chordae tendineae

strands of connective tissue that support the AV valves that connect to papillary muscles.

local factors regulate blood flow into individual capillaries by altering_

the diameters of precapillary sphincters

Coronary arteries

the heart's own set of blood vessels that supply the heart muscle.

Ventricles

the two more muscular bottom chambers.

Why is hypertension called the silent killer

usually it has no symptoms