Ch 44 Flashcards
What are the components of a circulatory system?
circulating fluid (ex:blood), a pump (heart), and vessels or spaces to hold the fluid
What are the two types of circulatory systems?
an open circulatory system: the circulating fluid leaves vessels to directly come in contact with tissue cells, closed system: the circulating fluid is always contained in vessels
characteristics of an open circulatory system
found in some mollusks and most arthropods including insects, the interstitial fluid and circulating fluid are one and same (hemolymph), a peristaltic heart produces low pressure, the fluid slowly percolates through the body in large sinuses or a hemocoel (slow delivery limits oxygen transport, active insects have separate tracheal system for O2 and colorless blood (no respiratory pigment, some mollusks and arthropods contain hemocyanin)
characteristics of a closed circulatory system
found in some invertebrates and all vertebrates, there are two fluids: interstitial fluid (which becomes lymph) and blood, in the vertebrates a chambered heart produces high pressure, blood is always contained in a system of tubes or pipes
functions of the vertebrate circulatory system
carry nutrients from digestive system to cells, carry oxygen from respiratory system to cells, carry metabolic wastes to excretory organs (carbon dioxide to respiratory surface and other wastes to liver and kidneys), afferent and efferent pathways for hormones, maintain fluid balance, defense, distribution of body heat
what two things is blood made up of?
plasma and cells
What is the ratio of plasma to cells?
55 plasma to 45 cells
What is blood comprised of? (Including percentages)
plasma is 55% of blood, water is 92% of plasma and proteings are 7% of plasma, cells are 45% of blood
What are the different types of blood cells?
leukocytes, erythrocytes, thrombocytes
What is plasma made up of? (including percentages)
92% water, 7% proteins (these proteins include albumins, globulins, and figrinogen), and various salts, gases, hormones, nutrients, and wastes
What are the blood’s cells made up of?
95% red blood cells, 4% platelets, and <1% white blood cells
What are the two types of leukocytes and what are some examples of each?
granular: neutrophils (phagocytic), eosinophils (allergic responses and some infections), basophils (release histamine and some infections), and agranular: lymphocytes (antibodies), and monocytes (macrophages)
What are thrombocytes?
platelets
What are erythrocytes?
red blood cells
How does blood clot? (the process)
Injury to the blood vessel, the injured vessel then constricts to reduce blood loss, platelets physically patch the break by sticking to the rough, cut edges of the vessel, as the platelets begin to gather the release substances that attract other platelets, the platelets become sticky and adhere to collagen fibers in the blood vessel wall, within about 5 minutes after injury they form a platelet plug, or a temporary clot, at the same time that the temporary clot forms, a stronger, more permanent clot begins to develop, more than 30 chemical substances interact in this complex process, the series of reactions that leads to clotting is triggered when one of the clotting factors in the blood is activated by contact with the injured tissue, prothrombin, a plasma protein manufactured in the liver, requires vitamin K for its production, in the presence of clotting factors, calcium ions, and compounds released from platelets, prothrombin is converted to thrombin, then thrombin catalyzes the conversion of the soluble plasma protein fibrinogen to an insoluble protein, fibren, once formed, fibrin polymerizes, producing long threads that stick to the damaged surface of the blood vessel and form the webbing of the clot, these threads trap blood cells and platelets which help strengthen the clot
What is the function of neutrophils? Eosinophils? Basophils? Lymphocytes? Monocytes?
phagocytosis; allergic responses and immune responses; prevention of inappropriate clotting; produce antibodies and destroy foreign cells; can differentiate to form macrophages and dendritic cells
What is the function of red blood cells? Platelets?
oxygen transport and carbon dioxide transport; essential for clotting
What do arteries do? What are the layers in the arteries?
Arteries provide elasticity, Tunica intima (INtima-inside of the artery): endothelium, tunica media (MEDia-middle layer): connective tissue and smooth muscle, tunica adventitia (outer layer): connective tissue with collagen
arterioles
provide resistance, arterioles are smaller arteries
capillaries
provide for exchange (single layer of endothelium and a basement membrane), the smallest, thin-walled exchange vessels through which blood and tissues exchange materials
What do veins and venules do?
they provide capacitance, which is space for the rest of the fluid, venules are smaller versions of veins much like arterioles are smaller versions of arteries
What do lymphatic capillaries and vessels do?
drain interstitial fluid
Can veins be closed off?
Yes, if their blood tries to move the wrong way valves can close them off
Arteries
carry blood AWAY from the heart
Veins
return blood to the heart
What is vasoconstriction? Vasodilation?
vasoconstriction is when arterioles constrict, vasodilation is when arterioles dilate, they do this to regulate blood pressure and the distribution of blood to the tissues
When are metarterioles used?
when muscles don’t need more blood because they’re not in use so the blood doesn’t need to be pumped through the capillaries, metarterioles directly link arterioles with venules
Do atria recieve blood or pump it? Ventricles?
Atria recieve blood, ventricles pump blood into the arteries
What animal is the only vertebrate with a single circuit system?
Fish, they have a 2 chambered heart with 1 atrium and 1 ventricle
What do reptiles have for a cardiovascular system that differs from mammals?
the reptilian heart has two atria and two ventricles, in most reptiles the wall separating the ventricles in incomplete so blood from the right and left chambers mixes to some extent, in crocodiles and alligators the septum is complete and the heart consists of four separate chambers
What do amphibians have for a cardiovascular system?
in amphibians, the heart consists of two atria and one ventricle, blood flows through a double circuit
What do birds and mammals have for a cardiovascular system?
in birds and mammals, the two atria and two ventricles separate oxygen-rich blood from oxygen-poor blood
What is the pattern of blood circulation in birds and mammals?
veins (conduct blood from organs)->right atrium->right ventricle->pulmonary arteries->capillaries in the lungs->pulmonary veins->left atrium->left ventricle->aorta->arteries (conduct blood to organs)->arterioles->capillaries->veins
Which side has oxygenated blood, left or right?
Left has oxygenated blood, right has deoxygenated
In the human heart there are 4 valves that prevent the backflow of blood. What are they and where are they?
The right atrioventricular valve (tricuspid valve): between the right atrium and ventricle, left atrioventricular valve (bicuspid valve): between the left atrium and ventricle, semilunar valves (two of them): aortic valve is between the left ventricle and the aorta, and the pulmonary valve is between the right ventricle and the pulmonary artery
Explain how each heartbeat is initiated by a ‘pacemaker’
the cardiac muscle fibers are joined by intercalated discs which are dense bands at the ends of cardiac muscle cells, these complex junctions contain gap junctions which make it easy for action potentials to occur, this allows ions to move easily through the gap junctions, allowing the entire atrial muscle mass to contract as one giant cell, the sinoatrial (SA) node, or the ‘pacemaker’ ensures that the heart beats in a regular and effective rhythm
Cardiac cycle
the cardiac cycle is what occurs during one complete heartbeat, during this heartbeat there is a period of contraction (systole) and a period of relaxation (diastole), during systole the “lub” sound is made which comes from the closing of the AV valves (both bicuspid and tricuspid), during diastole, you hear the “dub” sound which is the closing of the semilunar valves (both aortic and pulmonary)
blood pressure
blood pressure is the force that blood exerts against the inner walls of the blood vessel, it is greatest in the arteries and decreases as blood flows through the capillaries, blood pressure depends on how much blood you have (blood volume), how fast you’re trying to move it (cardiac output), and how much your blood sticks against vessels and how much the blood is slowed (peripheral resistance)
What does blood pressure depend upon?
blood pressure depends on how much blood you have (blood volume), how fast you’re trying to move it (cardiac output), and how much your blood sticks against vessels and how much the blood is slowed (peripheral resistance)
What is blood viscosity?
how thick/watery the blood is
What is peripheral resistance? What does it depend upon?
peripheral resistance is the resistance to blood flow in the body, it depends upon blood viscosity and the friction between blood and the blood vessel wall
How is heart rate regulated?
it is regulated mainly by the nervous system, it’s influenced by hormones and body temperature
How is cardiac output calculated?
stroke volume times heart rate (stroke volume depends on venous return and on neural messages and hormones, especially epinephrine and norepinephrine)
How is blood pressure calculated?
blood flow times peripheral resistance
What are baroreceptors?
specialized receptors in the walls of certain arteries and in the heart wall, they are sensitive to changes in blood pressure, when an increase in blood pressure stretches the baroreceptors messages are sent to the cardiac and vasomotor centers in the medulla of the brain
What happens when blood pressure increases?
the cardiac center stimulates parasympathetic nerves that slow heart rate, vasomotor center inhibits sympathetic nerves that constrict blood vessels, blood pressure is thus reduced
What is angiotensin?
it is a vasoconstrictor, a hormone that raises blood (angioTENSin-tensed blood vessels increase blood pressure)
What is aldosterone?
it helps regulate salt excretion which affects blood volume and blood pressure, we expel a lot of salt (pee) and lose a lot of water doing this which is what blood is mainly made of so it reduces blood volume and therefore the blood pressure
What does the lymphatic system do?
collects interstitial fluid and returns it to the blood, plays an important role in homeostasis of fluids, defends the body against disease by transporting white blood cells, absorbs lipids from digestive tract
lymphatic vessels
conduct lymph to the thoracic duct and right lymphatic duct in the shoulder region, ducts return lymph to the blood circulatory system
