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Flashcards in Chapter 34 Flashcards Deck (65):

What is a Circulatory System?

A system that moves substances into and out of cellular neighbourhoods.


What is Blood?

Blood is the transport medium in the circulatory system, typically it flows inside tubular vessels under pressure generated by a heart. Blood makes exchanges with interstitial fluid.


What is Interstitial Fluid?

Fluid in tissue spaces between cells.


What make up the body's internal environment and what does it work to do?

Blood and interstitial fluid are the components that make up the body's internal environment, and the body works to keep homeostasis.


What are the two main kinds of circulatory systems?

Open (most arthropods and mollusks) and closed (annelids and vertebrates).


What is an open circulatory system?

Blood moves through the heart and large vessels, but also mixes with interstitial fluid.


What is a closed circulatory system?

The blood remains inside a heart or blood vessel at all times, the total volume of blood moving continually away from the heart, through to vessels, and then back to the heart.


When does blood move fastest and when does it slow?

It moves fastest when confined to a few large vessels, and moves slowly when in blood capillaries; the vessels with the smallest diameter.


What did internally moistened sacs evolve into?

Lungs, which supported the move to dry land.


Explain the heart found in most fishes.

They have a one circuit, two chambered heart. The contractile force of this heart drives the blood through a capillaries bed inside each gill. From there the blood flows into a large vessel, then through capillary beds in body tissues and organs, and then back to the heart. Once the blood leaves the gill capillaries, it is no longer under much fluid pressure.


Explain the heart found in most amphibians.

The heart is divided into three chambers, with two atria emptying into one ventricle. Oxygenated blood flows from the lungs to the heart in one circuit, and a forceful contraction pumps it through the rest of the body in the second circuit. Oxygenated and oxygen-poor blood mix in the ventricle.


Explain the heart found in birds and mammals.

The heart has fully separate right and left halves, each with two chambers, and it pumps the blood in two separate circuits. With the two separate circuits, blood pressure can be regulated in each one. The strong contraction of the left ventricle pumps blood quickly through the systemic circuit, and the right ventricle can contract less strongly to protect the delicate lungs.


What is the pulmonary circuit? [Mammal heart]

Oxygen-poor, carbon dioxide rich, blood flows from the right half of the heart to the lungs. There it picks up oxygen, gives up carbon dioxide, and flows back into the left half of the heart.


What is the systemic circuit? [Mammal heart]

Longer than the pulmonary circuit, the heart's left half pumps oxygenated blood to tissues where oxygen is used and carbon dioxide forms in aerobic respiration. Blood gives up oxygen and picks up carbon dioxide at tissues, then flows to the heart's right half.


List the functions of blood.

1. Fluid connective tissue. 2. Carries oxygen, nutrients, and other solutes to cells and picks up their metabolic wastes and secretions (including hormones).3. Helps stabilize internal pH. 4. Highway for cells and proteins that protect and repair tissues.5. [Birds and Mammals] Helps keep body temperature within tolerable limits by moving excess heat to skin.


What dictates blood volume and how much does the average human have?

Body size and concentration of water and solutes dictate the blood volume, the average-sized human has about 5 litres of blood (6-8% of total body weight).


What is Plasma?

The fluid portion of blood, it's cellular portion consists of blood cells and platelets that arise from stem cells in bone marrow. 50-60% of the blood's total volume is plasma, and the plasma is 90% water. It's a transport medium for blood cells and platelets, as well as a solvent for hundreds of different plasma proteins and other molecules/ions.


What is a Stem Cell?

An unspecialized cell that retains a capacity for mitotic cell division. Some portion of its daughter cells divide and differentiate into specialized cell types.


What are Red Blood Cells?

Erythrocytes, or red blood cells, transport oxygen from lungs to aerobically respiring cells and carry carbon dioxide wastes from them. Mammals lose their red blood cell nucleus when they mature, becoming flexible disks with a depression in the centre. Oxygen binds to the hemoglobin, which when stored takes up 98% of the human red blood cell. It is what makes the blood appear red. A mature red blood cell has enough sugars and other molecules to live about 120 days.


What is a Cell Count?

A measure of the quantity of cells of one type per cubic millimeter of blood.


What are White Blood Cells?

Leukocytes, white blood cells, function in daily housekeeping activities and in defense. Some are phagocytes that engulf damaged, dead, or dying cells, or "nonself" chemicals. Some types sound alarms when viruses, bacteria, or other pathogens attack the body. They can differ in size, nuclear shape, and staining traits. Their numbers fluctuate with levels of activity and state of health. B cells and T cells are specialized for immune response.


What are Platelets?

Megakaryocytes are ten to fifteen times bigger than other blood cells that form in bone marrow, and they break up into platelets which are membrane-wrapped fragments of cytoplasm. One formed, a platelet can last five to nine days. They release substances that initiate blood clotting when activated.


What are Red Blood Cell Disorders?

Two few red blood cells or deformed one result in anemias. Oxygen delivery slows and metabolism falters. Polycythemia is a condition in which there are too many red blood cells. It makes blood more viscous and elevates blood pressure.


What are White Blood Cell Disorders?

Epstein-Barr virus causes infectious mononucleosis, in which too many monocytes and lymphocytes form. It causes fatigue, muscle aches, low-grade fever, and sore throats.


What is Agglutination?

A normal defense response where proteins called antibodies bind foreign cells and make them form clumps that attract phagocytes. It's important for blood donors to be the same blood type of the recipient, so that the body doesn't attack the donated blood.


What is ABO Blood Typing?

A method of analyzing variations in one type of self marker on red blood cells. There are two markers, and the presence of them determines if you have A, B, AB, or O (no markers present).


What is Rh Blood Typing?

Based on the presence or absence of the Rh marker, Rh+ blood cells bear this marker. Incompatible types can form problems in pregnancies.


What is the main artery in the body?

The aorta.


What does the Cardiovascular System do?

It distributes oxygen, nutrients, and other substances that enter the body by way of the digestive system and respiratory system. It moves carbon dioxide and other metabolic wastes to the respiratory and urinary systems for disposal.


What are Jugular Veins?

They receive blood from brain and from tissues of head.


What is the Superior Vena Cava?

Receives blood from veins of upper body.


What are the Pulmonary Veins?

The deliver oxygenated blood from the lungs to the heart.


What is the Hepatic Vein?

Carries blood that has passed through small intestine and then the liver.


What is the Inferior Vena Cava?

It receives blood from all veins below diaphragm.


What are the Iliac Veins?

They carry blood away from the pelvic organs and lower abdominal wall.


What is the Femoral Vein?

It carries blood away from the thigh and inner knee.


What are the Carotid Arteries?

They deliver blood to neck, head, and brain.


What is the Ascending Aorta?

It carries oxygenated blood away from the heart, it is the largest artery.


What are the Pulmonary Arteries?

They deliver oxygen-poor blood from the heart to the lungs.


What are the Coronary Arteries?

They service the incessantly active cardiac muscle cells of the heart.


What is the Brachial Artery?

Delivers blood to the upper extremities, blood pressure is measures here.


What is the Renal Artery?

It delivers blood to kidneys, where its volume, composition are adjusted.


What is the Abdominal Aorta?

It delivers blood to arteries leading to the digestive tract, kidneys, pelvic organs, lower extremities.


What are the Iliac Arteries?

They deliver blood to pelvic organs and lower abdominal wall.


What is the Femoral Artery?

Delivers blood to the thigh and inner knee.


What is the outermost layer of the heart?

The pericardium, a tough two-layered sac of connective tissue that anchors the heart to adjacent structures. A fluid between the layers lubricates the heart during its wringing motions, the inner layer attaches to the heart wall.


What is the heart wall?

Called the myocardium, it is bundled cardiac muscle cells held in place by strands of elastin and collagen. The crisscrossing strands accept the force of contraction, allowing the heart to change shape.


What lines the heart chambers and all blood vessels?

Endothelium, a kind of epithelium.


What happens during the cardiac cycle?

Heart muscles alternate through diastole and systole (relaxation and contraction). The relaxed atria expand with blood, fluid pressure forces the AV valves open. Blood is now able to flow into the relaxed ventricles, which expand as the atria contract. The ventricles contract, and fluid pressure in them rises so sharply above the pressure in the great arteries that both semilunar valves open, so blood flows out. The ventricles relax while the atria are filling out for a new cycle.Contraction of the ventricles is the driving force for blood circulation.


How do Cardiac Muscles contract?

They contract by ATP driven sliding-filament mechanisms.


What is the Cardiac Conduction System?

It initiates and distributes signals that tell other cardiac muscle cells to contract.


What is the Cardiac Pacemaker? And how does the Heart Beat?

The SA node, a clump of non-contracting cells in the right atrium's wall, have specialized membrane channels that let them fire action potentials about seventy times a minute. The SA node has spontaneous action potentials. A signal from this node starts the cardiac cycle, the signal spreads through the atria, causing them to contract. The signal simultaneously excites junctional fibres, which conduct it to the AV node, which is a clump of cells that is the only electric bridge to the ventricles. From the AV node, a signal travels along a bundle of fibres that branch in the septum, between the ventricles. The fibres extend down to the heart's lowest point and up the ventricle walls, and starting at the atria the cardiac muscle responds by contracting in a twisting motion, which ejects blood into the aorta and pulmonary arteries.


What are Arteries?

Rapid-transport vessels for blood pumped out of the heart's ventricles. They supply the arterioles. They have thick, muscular, elastic walls that bulge whenever a heartbeat forces a large volume of blood into them.


What are the Arterioles?

Smaller vessels where controls over the distribution of blood flow operates. These branch into capillaries, which are smaller blood vessels that form diffusion zones.


What are Venules?

Small vessels located between the capillaries and veins.


What are Veins?

Large vessels that deliver blood back to the heart and serve as blood volume reservoirs.


What is Blood Pressure?

A fluid pressure imparted to blood by ventricular contractions because the difference in pressure between any two points affects the flow rate. Resistance (slows the flow) rises as tubes narrow. Blood pressure depends on the total blood volume, how much blood the ventricles pump out, and whether the arterioles are constricted or dilated.


What is a Capillary?

A cylinder of endothelial cells that are one cell thick and wrapped in a basement membrane. They offer a huge surface area for the exchange of substances with the interstitial fluid.


What is Ultrafiltration?

Due to the high hydrostatic pressure at the arterial end of a capillary bed, fluid is forced out between cells of the capillary wall into the interstitial fluid. This fluid has high levels of oxygen, ions, and nutrients and allows movement of large quantities of essential substances from blood into interstitial fluid.


What is Capillary Reabsorption?

When blood continues on to the venous end of the capillary bed, hydrostatic pressure drops and osmotic pressure predominates. Water is drawn by osmosis from interstitial fluid into the protein rich plasma.


What is Edema?

When high blood pressure causes too much fluid to flow out or something slows the fluid return, interstitial fluid collects in tissues and results in swelling.


What is Hemostasis?

A process that can stop blood loss from small blood vessels that have become ruptured or cut, and can construct a scaffold for repairs.


What is Atherosclerosis?

When this happens, arteries thicken and lose elasticity as lipids build up in the arterial wall and narrow the lumen. It can lead to blocked arteries, resulting loss of oxygen to vital organs and in heart attacks and death.


What is Hypertension?

Refers to chronically high blood pressure even during periods of rest. The heart pumps faster, enlarging it to the point it pumps less efficiently.


What are Rhythms and Arrhythmias?

Abnormal heart rhythms that are not always dangerous, but can lead to problems in some people.