Term
| An electrical signal generated by a natural ________ in the heart wall sets each heartbeat in motion |
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Definition
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Term
| In sudden _______, the pacemaker malfunctions, the heart stops beating, blood flow halts and cells begin to die from lack of oxygen |
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Definition
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Term
| _______, if started within four to six minutes of the arrest, can keep some oxygenated blood moving to cells, but it cannot restart a heart |
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Definition
| Cardiopulmonary resuscitation (CPR) |
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Term
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Definition
| device with paddles that deliver an electric shock to the chest to reset the natural pacemaker |
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Term
| Vertebrates have a closed circulatory system, in which materials are exchanged across ______ |
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Definition
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Term
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Definition
| Organ system consisting of a heart or hearts and blood-filled vessels that distribute substances through a body |
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Definition
| muscular organ that pumps blood through a body |
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Definition
Circulatory fluid
In vertebrates, blood is a fluid connective tissue consisting of plasma and cells that form inside bones |
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Definition
| Circulatory system in which blood mixes with interstitial fluid and makes direct exchanges with cells |
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| Closed Circulatory System |
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Definition
Blood flows through a continuous system of vessels
Substances are exchanged between blood and cells of other tissues by diffusion across walls of capillaries |
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Term
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Definition
| Smallest blood vessels, where exchanges with interstitial fluid take place |
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Term
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Definition
| Circuit through which blood flows from the heart to the lungs and back |
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Term
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Definition
| Circuit through which blood flows from the heart to the body tissues and back |
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Term
| ________ move blood form the heart to arterioles |
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Definition
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Term
| The largest artery in the body is the ______ |
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Definition
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Term
| ____________ supply capillaries |
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Definition
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Term
| Capillaries drain into __________ that feed into veins |
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Definition
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Term
| ______ carry blood back to the heart |
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Definition
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Term
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Definition
| Large-diameter blood vessel that carries blood away from the heart |
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Term
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Definition
| Large artery that receives blood pumped out of the heart’s left ventricle |
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Term
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Definition
| Vessel that carries blood from an artery to a capillary |
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Term
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Definition
| Small-diameter vessel that carries blood from capillaries to a vein |
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Term
| The _______ carries blood to and from the lungs |
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Definition
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Term
| Oxygen-poor blood is pumped out of the heart’s right ventricle, through _______, to the lungs |
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Definition
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Term
| Return oxygen-rich blood to the heart's LEFT atrium |
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Definition
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Term
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Definition
| Vessel carrying blood from the heart to a lung |
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Term
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Definition
| Vessel carrying blood from a lung to the heart |
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Term
| The heart’s ______ ventricle pumps blood into the aorta, which branches into arteries and arterioles that carry blood to various body parts |
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Definition
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Term
| _________ delivers blood to the kidneys |
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Definition
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Term
| ____________ supply heart cells |
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Definition
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Term
| Oxygen-poor blood leaves the capillaries and flows through venules and veins to the heart’s ________ atrium |
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Definition
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Term
| Most blood moving through the systemic circuit flows through only one ________ |
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Definition
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Term
| The heart lies in the _______ cavity, beneath the breastbone and between the lungs |
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Definition
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Term
| It is protected and anchored by _______, a double-layered sac of connective tissue |
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Definition
pericardium
* FAT ALSO PROTECTS HEART* |
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Term
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Definition
| Heart chamber that RECEIVES blood from veins |
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Term
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Definition
| Heart chamber that pumps blood into arteries |
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Term
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Definition
| Vein that delivers blood from the upper body to the heart |
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Term
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Definition
| Vein that delivers blood from the lower body to the heart |
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Term
| Each _______ artery carries blood to a lung |
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Definition
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Term
| The right ventricle pumps it through the pulmonary valve and into the _______, a vessel that branches into two pulmonary arteries |
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Definition
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Term
| After passing through the lung, the now-oxygenated blood returns to the _______ via pulmonary veins |
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Definition
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Term
| _______ of the ventricles alone provides the force that powers movement of blood through blood vessels |
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Definition
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Term
| Contraction of atria only fills the _______ |
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Definition
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Term
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Definition
| Sequence of contraction and relaxation of heart chambers that occurs with each heartbeat |
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Term
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Definition
| Relaxation phase of the cardiac cycle |
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Term
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Definition
| Contractile phase of the cardiac cycle |
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Term
| Steps of the Cardiac Cycle |
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Definition
Relaxed atria fill; fluid pressure opens AV valves and blood flows into relaxed ventricles
Contracting atria squeeze more blood into relaxed ventricles
Ventricles start contracting; rising pressure pushes AV valves shut, and opens aortic and pulmonary valves
As blood flows into the arteries, pressure in the ventricles declines and the aortic and pulmonary valves close |
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Term
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Definition
Cardiac pacemaker
Group of heart cells that spontaneously emits rhythmic signals that cause contraction |
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Term
| _______ spread across the atria by way of gap junctions, causing them to contract |
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Definition
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Term
| Artioventricular (AV) node |
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Definition
| Clump of cells that is the electrical bridge between the atria and ventricles |
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Term
The action potential in the atria excites fibers that conduct it to the ________, then along other fibers in the septum between the heart’s left and right halves
In response to the signals, ventricles contract from the bottom up, with a twisting motion |
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Definition
| atrioventricular (AV) node |
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Term
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Definition
| the protein-rich fluid portion of blood, distributes essential nutrients and solutes to cells |
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Term
| The function of the circulatory system is to move ______ |
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Definition
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Term
| Blood facilitates internal communications by distributing _______ and serves as a highway for cells and proteins that protect and repair tissues |
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Definition
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Term
| Plasma consists mainly of |
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Definition
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Term
| Platelets and all blood cells arise from stem cells in ____ |
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Definition
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Term
| Plasma constitues _______ of blood |
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Definition
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Term
| Red blood cell (ertythrocyte) |
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Definition
| Hemoglobin-filled blood cell that carries oxygen |
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Term
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Definition
| measure of the quantity of cells of one type in 1 microliter (1/1,000,000 liter) of blood |
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Term
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Definition
| disorder in which the red blood cell count declines or red blood cells are defective |
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Term
| White blood cells (leukocytes) |
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Definition
have roles in day-to-day tissue maintenance and repair and in defenses against pathogens
The cells differ in their size, nuclear shape, and staining traits, as well as function |
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Term
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Definition
| Most abundant white cells. Phagocytes that engulf bacteria and debris |
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Term
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Definition
| attack larger parasites, such as worms |
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Term
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Definition
| secrete chemicals that have a role in inflammation |
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Term
| What are the two types of lymphocytes |
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Definition
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Term
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Definition
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Term
| T cells mature in _______ |
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Definition
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Term
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Definition
| adhere to an injured site and help form a blood clot |
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Term
| ______ form in bone marrow and break up into membrane-wrapped fragments of cytoplasm (platelets) that last five to nine days |
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Definition
| Large cells (megakaryocytes) |
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Term
| ______ stops blood loss from an injured vessel and provides a framework to begin repairs |
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Definition
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Term
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Definition
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Term
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Definition
Stimulus: A blood vessel is damaged
Phase 1 response: Vessel constricts
Phase 2 response: Platelets stick together, plugging the site
Phase 3 response: Clot formation
Enzyme cascade activates enzyme thrombin
Thrombin converts fibrinogen to fibrin threads
Fibrin forms a net that entangles cells and platelets, forming a clot |
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Term
| Thick-walled arteries smooth out _______ |
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Definition
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Term
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Definition
| Brief stretching of artery walls that occurs when ventricles contract |
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Term
| As the artery wall _______, it keeps blood flowing away from the heart |
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Definition
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Term
| In the systemic circuit, the body adjusts the distribution of blood by altering the diameter of _______ |
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Definition
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Term
| ______ that rings each arteriole responds to commands from the central nervous system |
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Definition
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Term
| _________ causes vasodilation (widening) of arterioles in the extremities and vasoconstriction (narrowing) of arterioles of the gut |
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Definition
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Term
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Definition
| Widening of a blood vessel when smooth muscle that rings it relaxes |
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Term
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Definition
| Narrowing of a blood vessel when smooth muscle that rings it contracts |
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Term
| Oxygen, CO2, and other substances are exchanged across _______ walls |
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Definition
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Term
| Many veins, especially in the legs, have __________ that help prevent backflow |
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Definition
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Term
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Definition
Blood pressure when ventricles are contracting
Highest pressure of a cardiac cycle |
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Term
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Definition
Blood pressure when ventricles are relaxed
Lowest pressure of a cardiac cycle |
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Term
| Blood pressure depends on: |
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Definition
Total blood volume
How much blood the ventricles pump out (cardiac output)
The degree of arteriole dilation |
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Term
| Inability to regulate blood pressure can result in _________ (resting blood pressure above 140/90) |
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Definition
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Term
| Blood flow slows in capillaries because their collective cross-sectional area is far ______ than that of the arterioles that deliver blood to them, or the veins that carry blood away |
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Definition
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Term
| Substances leave a capillary by ________, ________, or ___________ |
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Definition
| diffusion, exocytosis, or in fluid that seeps out between cells |
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Term
| Fluid that seeps out of a capillary at the arterial end is balanced by _______ of water nearer the vein end |
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Definition
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Term
| Normally, there is a small net ______ flow of fluid from capillaries |
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Definition
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Term
| Blood pressure in veins is _____-, but several mechanisms keep blood moving |
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Definition
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Term
| _______ are the boy's largest blood reservoir. |
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Definition
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Term
| ________ are the leading cause of death in the United States |
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Definition
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Term
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Definition
| below-average resting cardiac rate |
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Term
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Definition
| faster than normal heart rate |
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Term
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Definition
| arrhythmia in which the atria do not contract normally, but instead quiver |
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Term
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Definition
| can cause death – a defibrillator may reset normal rhythm |
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Term
| Most cholesterol (lipid) in blood is bound to protein carriers such as _______ and ______ |
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Definition
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Term
| __________ cause lipid buildup in endothelial linings of arteries |
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Definition
| Low-density lipoproteins (LDLs) |
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Term
| __________ are metabolized by the liver, which uses them in the formation of bile |
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Definition
| High-density lipoproteins (HDLs) |
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Term
| In ____________, buildup of lipids in the arterial wall narrows the space inside the vessel (lumen) and impairs blood flow |
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Definition
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Term
| Excess fluid that leaves capillaries of the circulatory system returns to blood by way of the _________ |
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Definition
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Term
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Definition
consists of lymph capillaries and vessels that collect water and solutes from interstitial fluid, then deliver them to the circulatory system\
System of vessels that takes up interstitial fluid and carries it (as lymph) to the blood |
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Term
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Definition
| Fluid in the lymph vascular system |
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Term
| ________ empty lymph into veins in the lower neck |
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Definition
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Term
| Functions of the Lymph Vascular System |
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Definition
It collects water and plasma proteins that leaked out of capillaries and returns them to the circulatory system
It delivers fats absorbed from food in the small intestine to the blood
It transports cellular debris, pathogens, and foreign cells to lymph nodes, which serve as the system’s disposal sites |
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Term
| ________ include tonsils and some patches of tissue in the wall of the small intestine and appendix |
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Definition
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Term
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Definition
| Small mass of lymphatic tissue through which lymph filters; contains many lymphocytes (B and T cells) |
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Term
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Definition
| Large lymphoid organ that filters blood |
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Term
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Definition
| Endocrine gland beneath breastbone; makes hormones that help T cells mature |
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Term
| Before entering blood, lymph is filtered through __________ |
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Definition
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Term
| When something is identified as __________, lymphocytes multiply to destroy that threat |
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Definition
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