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Biology 12 > Circulation > Flashcards

Circulation Flashcards

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1
Q

What is the circulatory system?

A

-bring nutrients to and take wastes away from the cells
-consists of the heart and blood vessels
-consists of pulmonary circulation and systemic circulation
^pulmonary circulation consists of the blood flow to and from the lungs only
^systemic circulation consists of the blood flow to and from the body

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2
Q

What are blood vessels?

A
  • tubes that carry blood from the heart to the tissues(arteries & arterioles)and then back to the heart(veins & venules), capillaries connect the arterioles to venules and exchange material with the tissues
  • arteries carry blood away from the heart(except for pulmonary arteries & umbilical arteries carry deoxygenated blood away from the heart to the lungs)
  • veins carry blood toward the heart(except for pulmonary veins & umbilical veins which carry oxygenated blood toward the heart)
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3
Q

What are arteries and arterioles?

A
  • arteries & arterioles carry blood away from the heart
  • have thick walls composed of 3 layers which have muscle fibers, elastic fibers and supporting tissues
  • muscle fibers give the arteries strength and allows them to constrict and dilate
  • elastic fibers allow them to expand and contract(pulse)
  • arteries branch into arterioles which are smaller branches of arteries and provide arteries oxygen and nutrients
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4
Q

What are veins and venules?

A
  • veins carry blood back toward the heart
  • venules drain blood from the capillaries and then join to form a vein
  • veins have no thick middle layer of muscle and elastic and therefore have no blood pressure
  • veins have valves, which allow blood to flow only toward the heart when they are open, and prevent backflow of blood when they are closed
  • skeletal muscle contractions along with the valves help return the blood back to the heart(especially when going against gravity)
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5
Q

What are capillaries?

A
  • capillaries branch from the arterioles into a network of vessels that increase the surface area the blood can reach
  • one cell layer thick to allow for optimal diffusion and transport across the walls(exchange of nutrients and wastes)
  • capillaries have sphincter muscles which encircle the entrance to each capillary so that the blood flow to different areas of the body can be controlled at any one time(i.e. capillary beds in the muscles are completely opened when exercising while the capillary beds in the digestive system are partially closed to decrease the blood flow there)
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6
Q

What is the heart?

A
  • a four chambered organ about the size of a fist that is made of muscle that allows it to contract and relax, pumping blood to vessels
  • the myocardium is the major portion of the heart and is composed of cardiac muscle
  • the heart is covered by the pericardium(epithelial & fibrous tissue); forms the pericardial sac, which encloses the heart and is filled with lubricating liquid
  • right side of the heart pumps blood to the lungs(pulmonary) and the left side pumps blood to the rest of the body(systemic)
  • a thick wall called the septum separates the two sides
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7
Q

Describe the heartbeat

A
  • the heartbeat has two phases:atrial contractions & ventricular contractions
  • in the first phase, the atria are contracting and the ventricles are relaxing
  • in the second phase, the ventricles are contracting and the atria are relaxing
  • the sound “lub” in “lub-dub” is the closing of the atrioventricular valves, the sound “dub” is the closing of the semilunar valves
  • the heart beats about 70 times a minute and about 100 000 times a day
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8
Q

How is the heartbeat controlled?

A
  • the heartbeat is intrinsic; the heart cells beat without nerves telling them what to do
  • purkinje fibers send the electrical message down to the ventricles causing them to contract; the contraction begins at the base of the heart and moves up like a wave
  • the heart can keep a steady beat on its own but the rate of the heartbeat is under nervous control; controlled by the medulla oblongata which can speed up or slow down the heart rate according to stimuli received by the autonomic nervous system
  • stress, oxygen levels, and blood pressure affect the heart rate
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9
Q

What is the nodal tissue?

A
  • a special tissue in the heart
  • has both muscular and nervous tissue properties
  • has 2 nodal regions
  • SA node: found on the upper back wall of the right atrium, it initiates the heartbeat by sending out an automatic signal about every 0.85 secs to make the atria contract; it’s also called the pacemaker because it keeps the heartbeat regular
  • AV node: receives the signal from the SA node and then sends the signal along special conducting fibers called the AV bundle in the septum and then to the purkinje fibers
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10
Q

What is the cardiac cycle?(deoxygenated)

A
  1. deoxygenated blood enters right atrium from superior & inferior vena cava
  2. right atrium contracts forcing blood through the tricuspid valve into the right ventricle
  3. right ventricle contracts sending blood through the pulmonary semilunar valve into the pulmonary trunk which divides the pulmonary arteries to the left and right lungs
  4. pulmonary arteries take deoxygenated blood to the lung capillaries where CO2 diffuses out and O2 diffuses in
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11
Q

What is the cardiac cycle?(oxygenated)

A
  1. oxygenated blood enters the pulmonary veins which take blood from the lungs to the left atrium
  2. left atrium contracts forcing through the bicuspid valve into the left ventricle
  3. left ventricle contracts sending blood through the aortic semilunar valve into the aorta, which branches into all the the other major arteries taking oxygenated blood to the entire body when oxygen is diffused into the tissues
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12
Q

What is blood pressure?

A
  • the pressure of the blood against the wall of a vessel; the pumping that’s created by the heart
  • the expanding and recoiling of an arterial wall that can be felt in any major artery that runs near the the surface of the body; the radial and carotoid arteries are common places
  • measured in mmHg
  • blood pressure accounts for the flow of blood in the arteries & arterioles while skeletal muscle contractions account for the flow of blood in the venules & veins
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13
Q

What is systolic and diastolic blood pressure?

A

-systolic blood pressure is the highest arterial pressure reached during ejection of blood from the heart(ventricles contracting)
-diastolic blood pressure is the lowest arterial pressure, which occurs while the ventricles are relaxing
-normal blood pressure:
systolic pressure - 120
diastolic pressure - 80

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14
Q

How does blood pressure increase/decrease?

A
  • b.p. increases as physical activity increases due to the need for more oxygen and food to get to the muscles; an increase in b.p. allows the blood to get through the body faster
  • blood pressure drops as blood travels further from the heart; arteries(120), arterioles(70), capillaries(25), venules(10), veins(0-5)
  • b.p. drops as you go through the different blood vessels due to an increase area from arteries to arterioles to capillaries
  • blood velocity also decreases to allow for optimal filtration and exchange at the capillary level
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15
Q

How does circulation work in fetuses?

A
  • the fetus does not breathe air or eat any nutrients so it must get all of its oxygen and nutrients from the mother; the material enters the fetus through the placenta
  • the fetus is inside the mother’s womb, which is filled with a fluid called amniotic fluid
  • exchange of nutrients and wastes occur at the placenta instead of in the lungs
  • at birth all fetal modifications close due to the pressure of the air outside the womb; this ensure that there is no mixing of oxygenated and deoxygenated blood; blue baby will result if any of the fetal modifications do not close
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16
Q

What are some fetal modifications?

A
  • oval opening(foramen ovale): between the 2 atria covered by a flap; passes blood from the right atrium bypassing the pulmonary circulation
  • arterial duct(ductus arteriosus): connects the pulmonary artery with the aorta; directs the blood being pumped to the lungs straight to the aorta bypassing the pulmonary circulation
  • umbilical arteries & veins: blood vessels that travel to and from the placenta; a membrane shared by mom and baby; where the exchange of nutrients and wastes occur
  • venous duct(ductus venosus): connects umbilical vein to the vena cava; passes blood fom the umbilical vein(high nutrients) bypassing the liver to the vena cava(to the heart)
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17
Q

What is blood?And what is it composed of?

A
  • the material that the blood vessels transport
  • composed of plasma(liquid portion), red blood cells(erythrocytes), leukocytes(white blood cells), and platelets(cell fragments)
  • nutrients, oxygen, carbon dioxide, hormones, antibodies, urea, and heat is carried
  • the average person has about 5-6L of blood
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18
Q

What are the functions of blood?

A
  • helps maintain homeostasis
  • transports gases, wastes, and nutrients
  • clots(seals injuries)
  • fights infections
19
Q

What is plasma?

A
  • the liquid portion of blood; makes up 55% of blood volume

- plasma contains water, organic, and inorganic substances

20
Q

What is blood proteins?

A
  • found within the plasma
  • required for the transport for many molecules(e.g. cholesterol since it’s insolube in plasma and must be carried by proteins)
  • contribute to the viscosity of blood
  • contribute to osmotic pressure, which maintains blood volume
21
Q

What are the formed elements of blood?

A
  • red blood cells(erythrocytes)
  • white blood cells(leukocytes)
  • platelets(thrombocytes)
22
Q

What are red blood cells?

A
  • small, biconcave, disk-shaped cells without nuclei
  • make up 95% of formed elements
  • formed by stem cells found in the bone marrow of the skull, ribs, vertebrae, and the ends of long bones
  • transport oxygen & some carbon dioxide
  • live for 120 days and are then broken down by the liver and spleen
  • also called erythrocytes
23
Q

What are platelets?

A
  • used in blood clotting
  • also called thromobocytes
  • made from the fragmentation of large cells called megakaryocytes in the red bone marrow
24
Q

What is blood clotting?

A
  • -after an injury, coagulation or “clotting” occurs in order to prevent excessive blood loss
  • requires platelets, prothrombin, and fibrinogen
  • fibrinogen and prothrombin are plasma proteins; they are manufactured by using vitamin K and deposited into the blood by the liver
25
Q

What are white blood cells?

A
  • also called leukocytes
  • the body’s second line of defense(1st line of defense is the skin and HCl in the stomach lining)
  • along with antibodies, WBC are used to fight infections
  • larger than RBC, have a nucleus and appear white
  • there is 1 WBC for every 600 RBC
  • lymphocytes secrete proteins called antibodies which combine with foreign substances to inactivate them
  • red bone marrow continually produces WBC and keeps a reserve ready just in case; if an invasion occurs the reserves of WBC are released and manufacturing of more WBC begins(this causes fever)
  • WBC are specific for various illnesses so their count can help doctors diagnose patients
26
Q

What is the lymphatic system?

A
  • part of the circulatory system since it consists of lymph(a fluid that comes from the blood & returns to the blood by way of the lymphatic vessels)
  • consists of lymph vessels, lymph nodes, and lacteals
  • the fluid in the lymph vessels is called lymph; it’s formed from bits of blood & other body liquids, called interstitial fluid or tissue fluid, that collect in the spaces between cells
  • the lymph carries some nutrients, especially fat; it distributes germ-fighting white cells, and picks any particles that are too big(cell debris, fat globules, and tiny protein particles)to be absorbed through the capillary membrane
27
Q

What are lymph vessels?

A
  • lymph vessels carry lymph from the body tissues back into the blood stream so it is a one-way system
  • there are lymph vessels and veins(no blood pressure; they use valves; the pressure form the blood, and skeletal muscle contractions to return lymph to circulation)
  • the lymph from the upper right body is emptied into the blood at the right lymphatic duct; the lymph enters the right subclavian vein
  • the lymph from the rest of the body is emptied into the blood at the thoracic duct, the lymph enters the left the subclavian vein
28
Q

What are lymph nodes?

A
  • trap and filter bacteria and cell debris
  • produce lymphocytes(antibodies)
  • located in many different areas such as the neck, groin, and axillary
  • tonsils, appendix, spleen(also stores blood), thymus are made of lymphatic tissue
29
Q

What are the four blood types?

A
  • A
  • B
  • AB
  • O
30
Q

What are blood types?

A
  • an individual may have one an antigen present in their blood
  • each individual carries antibodies in his/her plasma to the antigens and present on that individual’s red blood cells
  • if an individual has type A blood, they have antibody B and vice versa
  • blood recipients may only receive donated blood for which they have antibodies for(eg type A blood has antibodies for type B & vice versa, type AB has no antibodies, type O has A & B antibodies); if the blood recipient received wrong type of blood, the body will attack the blood as though it is an invading substance
31
Q

What is agglutination?

A
  • if the same antigen and antibody are present, agglutination(or clumping) of red blood cells will occur(can cause death)
  • eg: type B blood will have clumping if there’s an anti-B, but not if there’s anti-A
32
Q

What is rH factor?

A
  • there is rH positive and rH negative
  • another antigen found on red blood cells
  • rH negative individuals do not normally make antibodies to the rH factor, but they will make them when exposed to the rH factor
33
Q

Why is rH factor very important during pregnancy?

A
  • if the mother is rH negative and father is rH positive, the child may be rH positive
  • before or during childbirth, a few of baby’s blood cells may get into mom
  • mom then produces antibodies to the rH factor
  • if she gets with another rH positive baby, her anti-rH antibodies can cross placenta during pregnancy and cause agglutination of baby’s RBC and that can kill the baby
  • treatment: immediately after birth, mother gets injection of antibodies that destroy any of the red blood cells left over from the baby, before the mother has a chance to start producing her own antibodies
34
Q

What are the different genotypes for each blood type?

A
  • type A: IaIa or Iai
  • type B: IbIb or Ibi
  • type AB: IaIb
  • type O: ii
35
Q

What is the a pathogen?And do we combat them?

A
  • an organism or virus that causes disease(bacteria, viruses, etc)
  • sanitation
  • body self defenses
  • antibiotics
  • vaccinations
36
Q

What is first defense?

A
  • the skin and mucous membranes
  • the skin is tough and waterproof and anywhere there is entry there are secretions that coat the openings essentially preventing entry
37
Q

What is second defense?

A
  • when the unwanted pathogen passes the first line of defense, it goes to the second defense
  • white blood cells and antibiotics are second defense and they fight infections
38
Q

What do white blood cells do?(specifically)

A
  • they come and ingest the invader thereby killing it and “learning” about it
  • then they “teach” other cells about the invader and creates antibodies
39
Q

What are antibodies?

A
  • proteins that attach to invading pathogens
  • produced by B Lymphocytes in response to invading pathogens
  • each lymphocyte can produce can only produce one type of antibody that is specific for one type of invader
  • when an antibody binds to an invader the invader becomes inactive, and therefore harmless to the individual; each antibody fits its invader like a lock and key
  • if an individual is immune to an invader he/she has antibodies to that particular invader; memory lymphocytes can remain in the blood for years ready to produce antibodies again if the same invader is detected
40
Q

What are the steps for second defense?

A
  • macrophage(white blood cell)ingests a pathogen, inactivates it, and then displays the antigen on its surface
  • helper T-cell is activated to divide by the macrophage by binding to the inactive antigen on the macrophage; helper T-cell multiplies and produce lymphokines which are chemical signals that regulate B-cells and T-cells
  • helper T-cells and macrophages create killer T-cells that destroy infected cells
  • helper T-cells also bind with B-cell to activate it to divide
  • B-cell divide into plasma cells which mass produce the antibody
  • antigen-specific memory cells are also generated
41
Q

What is active immunity

A
  • occurs after the recovery from a disease or from a vaccine
  • due to the production of antibodies by the organism itself after the body’s defence mechanisms have been stimulated by antigens
42
Q

What is passive immunity?

A
  • achieved through pregnancy, breast feeding, and emergency injections
  • due to the acquisition of antibodies received from another organism, in which active immunity has been stimulated
  • used when a person has already been exposed to the disease and cannot wait to produce memory cells and antibodies
  • the patient will recover faster but has not had the chance to produce their own memory cells for the next time they encounter the disease
  • babies receive antibodies through the placenta and are protected from any diseas the mother had; these antibodies only last about 3-6 months after birth
43
Q

What are vaccines?

A
  • a form of active immunity
  • an injected attenuated bacteria/virus(shape is present but can no longer cause a disease)
  • the primary response to the injection takes several days, during these days there is less antibody
  • the secondary response follows a second injection, which causes the number of antibodies to rise rapidly(booster shot); some memory cells are already present so they transform into plasma cells producing antibodies and preventing the occurrence of a disease if it arises

Biology 12 (11 decks)

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