Bio 12 Ch12 Cardiovascular Sys Notes Package

8/13/2019 Bio 12 Ch12 Cardiovascular Sys Notes Package

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Biology 12 Chapter 12 Notes *KWP Ve2.0 Page 1of 16

Biology 12 - Chapter 12 Cardiovascular system

YouTubevideo:The Circulatory System

http://www.youtube.com/watch?v=NJzJKvkWWDc12.1 The Blood Vessels

The Arteries

Arteries and arteriolestakeblood away from the heart.

The largest artery is the aorta. The middle layer of an artery

wall consists of smooth musclethat can constrict to regulateblood flow and blood pressure.

Arterioles can constrict ordilate, changing blood pressure.

The Capillaries Capillarieshave walls only one cell thick

to allow exchange of materials withtissue fluid.

Not all capillary beds are opened at thesame time. Eg. - Contraction of asphincter muscle closes off a capillarybed(** network of many capillaries **)and blood can flow through anarteriovenous shuntthat bypasses thecapillary bed.
http://www.youtube.com/watch?v=NJzJKvkWWDchttp://www.youtube.com/watch?v=NJzJKvkWWDchttp://www.youtube.com/watch?v=NJzJKvkWWDc


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The Veins

Venulesdrain into veins that take blood tothe heart.

Veins have much less smooth muscle andconnective tissue than an artery.

Veins often have valves that prevent thebackward flow of blood when closed.

QuestionsQ: Name the 3 types of major vessels in the circulatory system and their function; rankthem in order from largest diameter to smallest.A:Veins > Arteries > CapillariesVeins: blood vessels that transport blood back to the heart.Arteries: blood vessels that carry blood away from heart.Capillaries: Join arterioles (small arteries) to venules (small veins)Q: What are 2 major structural differences between arteries and veins?

A:1. The walls of veins have three layers of tissues like the arteries but veins are much thinnerand less elastic and muscular than arteries.2. Veins have valvesthat help in the process of returning blood to the heart by preventing bloodfrom flowing reverse, which do not exist in arteries.Q: What is the function of an rteriovenous shunt? (in plain English would be nice)A:It allows blood to flow between an artery and a vein without having to go through capillaries.Q: What is the largest artery? What are the largest veins?A:Largest artery: the aorta; largest veins: the superior and inferior vena cava

12.2 The Heart

(or pulmonary valve)

Cardiac muscle

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The heart muscle forms the myocardium. The pericardiumis the outer membranous sac. The septumis a wall dividing the right and left sides. The right and left atriaempty into the right and left ventriclesrespectively. Atrioventricular valvesoccur between the atria and ventricles and semilunar valvesoccur

between the ventricles and the attached arteries.

Passage of Blood through the Heart

Blood follows this sequence through the heart:

The oxygen rich and oxygen poor blood never mix.

Superior

and

inferior

vena cava

RightAtrium

RightVentricle

Pulmonaryarteries

Pulmonaryveins

LeftAtrium

LeftVentricle

Aorta

via: lung


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The Heartbeat

Systoleis the contraction of heart chambers. Diastoleis their relaxation. The heart sounds, lub-dubare due to the closing of the atrioventricular valves, followed

by the closing of the semilunarvalves.

Intrinsic Control of Heartbeat

The SA-(sino-atrial) node(pacemaker)initiates the beat andcauses the atria to contract onaverage every 0.85 seconds.

The AV (atrio-ventricular) nodeconveys the stimulus and initiatescontraction of the ventricles.

The signal for the ventricles tocontract travels from the AV nodethrough the atrioventricularbundle to the smaller Purkinjefibers.


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Extrinsic Control of Heartbeat

A cardiac control center in medulla oblongataspeedsup or slows down the heart rate by way of theparasympathetic (slower heart rate)and thesympathetic (increases heart rate)systems.

The PSNS and SNS

The autonomic nervous system (means automatic)helps regulate internal organs and glanssubconsciously.

The parasympathetic nervous system (PSNS)regulates the resting activities. The sympathetic nervous system (SNS)regulates the stimulating activities.

Heart Hormones

Hormones epinephrine and norepinephrinealso stimulate fasterheart rate. They arederived from the amino acid tyrosine.


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The Electrocardiogram

An electrocardiogram (ECG)is a recording of the electrical changes that occur in themyocardium during a cardiac cycle

Aortal depolarization creates the QRS wave. Repolarization of the ventricles produces the T wave.

Questions

Q: What do P waves, QRS signals and T waves signal as happening soon?A:The P wavesindicate that the atria are about to contract. The QRS complex signals that theventricles are about to contract. The T wavesindicates that the ventricular muscle fibers arerecovering from contractions (ventricular repolarization).

Q: What is ventricular fibrillation?A:Ventricular fibrillationis a type of abnormalities that can be detected by anelectrocardiogram. It causes uncoordinated contraction of the ventricles. Such abnormalities canbe caused by an injury or drug overdose. Once the ventricles are fibrillating, they must bedefibrillated by applying a strong electrical current for a short period of time. Then the SA nodemay be able to re-establish a coordinated beat.

Q: Explain to a friend why the atrial muscles contract first, followed by the ventricularmuscles?A:The contraction of the atrium causes the blood pressure in the atrium to exceed that of the

ventricle, which forces the AV valves open and allows the blood the enter the ventricles. Whenthe ventricles are full, it contracts to send blood out of the heart.


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12.3 The Vascular Pathways

1) The Pulmonary Circuit

The pulmonary trunkfrom the right ventricle branches into two pulmonary arteries, thenbranch into four, which take blood to the lungs. Four pulmonary veins return blood tothe left atrium.

RightVentricle

2pulmon

aryarteries

4pulmonary

arteries

lung

4pulmon

aryveins

Leftatrium


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2) The Systemic Circuit

The systemic circuitstarts with the aorta fromthe left ventricle.

The aorta branches with an artery going to aspecific organ.

Generally, an artery divides into arterioles andcapillaries which then lead to venules

The vein that takes blood to the vena cavaoften has the same name as the artery thatdelivered blood to the organ

In the adult systemic circuit, arteries carry bloodthat is relatively high in oxygen and relativelylow in carbon dioxide. This is the reverse of the pulmonary circuit

Blood in arteries

Blood pressure due to the pumping of the heart accounts for the flow of blood in thearteries.

Systolic pressureis high when the heart expels the blood. Diastolic pressureoccurs when the heart ventricles are relaxing. Bothdecreaseas blood enters more and more arterioles and arteries (capillaries, venules

and veins).

Blood flow in capillaries

Blood moves slowlyin capillaries because there are more capillaries than arterioles. This allows time for substances to exchangewith tissues.

Blood flow in veins Venous return is dependent upon:

skeletal muscle contraction

Leftventricle

Aorta arteries

(*Specific

organs)

Arterioles

Capiliaries

Venules

VeinsVenaCava

RightAtrium


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presence of valves in veins respiratory movements

Compressionof veins causes blood tomove forward past a valvethat thenprevents it from returning backward.

Changes in thoracic and abdominalpressurethat occur with breathingalsoassist the blood in flowing Varicose veinsdevelop when the valves of

veins become weak Hemorrhoidsare due to varicose veins in

the rectum Phlebitis in inflammationof a vein and can

lead to a blood clot and possible death.

QuestionsQ: Do all arteries carry oxygen-rich blood and all veins carry oxygen-poor blood?A: No, not all arteries carry oxygen-rich blood, and not all veins carry oxygen-poor blood.

Pulmonary arteriescarry oxygen-poor blood, while pulmonary veinscarry oxygen-rich blood.Q: Where does the heart gets its own blood (that carries nutrients and oxygen) from?A: The coronary arteriesserve the heart muscle itself, supplying blood forthe heart.

Q: Why might someone faint and why would this be beneficial?A: Someone might feint since by falling down, their body as well asblood flow are not overcoming gravity. Once they lay in a horizontalposition, their blood flow would be less hindered.

12.4 Blood

Blood composition Blood separates into two main parts: plasmaand cells Plasmacontains mostly water (90-92 )andplasma proteins (7-8 ), but it also contains

nutrients and wastes Ex. Albumin is a large plasma protein that

transports bilirubin, a breakdown product ofhemoglobin


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The Red Blood Cells Red blood cellscontain hemoglobinfor oxygen

transport Each hemoglobin carries 4 oxygen molecules Red blood cells lack a nucleusand have a ~120day life span When worn out, the red blood cells aredismantled in the liver and spleen Iron is reused by the red bone marrow where

stem cells continually produce more red bloodcells

Lack of enough hemoglobin results in anemia. The kidneys produce erythropoietinto increase

blood cell production when oxygen levels are low. (possibility for drug abuse in athletes)

The White Blood Cells A few YouTubevideos:

How White Blood Cells Work:http://www.youtube.com/watch?v=0TvTyj5FAaQWhite Blood Cell Chases Bacteria:http://www.youtube.com/watch?v=JnlULOjUhSQUnderstanding Allergies:http://www.youtube.com/watch?v=UfLAwO4_NTQ

White blood cells havea) a nucleus b) arefewer in number andc) defend againstdisease. Granular leukocytes:

(neutrophils, basophilsand eosinophil)

Carry enzymesproteinsand helpdefend againstmicrobes Some white blood cells

live a long time Monocytes(phagocytic

dendritic cells and macrophages) Dendritic cellsare present in tissues that are in contact with the environment (i.e. skin,

nose, lungs and intestines) Once they have captured a microbewith their long, spiky arms, called dendrites, they

stimulate other white blood cells to defend the body Macrophages(well known as ferocious phagocytes) play similar roles in other organs (i.e.:

liver, kidney and spleen) Lymphocytes(2 types: B lymphocytes and T lymphocytes) Assist body in immunity Infectious mononucleosisis characterized by excessive B lymphocytes
http://www.youtube.com/watch?v=0TvTyj5FAaQhttp://www.youtube.com/watch?v=0TvTyj5FAaQhttp://www.youtube.com/watch?v=0TvTyj5FAaQhttp://www.youtube.com/watch?v=JnlULOjUhSQhttp://www.youtube.com/watch?v=JnlULOjUhSQhttp://www.youtube.com/watch?v=JnlULOjUhSQhttp://www.youtube.com/watch?v=UfLAwO4_NTQhttp://www.youtube.com/watch?v=UfLAwO4_NTQhttp://www.youtube.com/watch?v=UfLAwO4_NTQhttp://www.youtube.com/watch?v=UfLAwO4_NTQhttp://www.youtube.com/watch?v=JnlULOjUhSQhttp://www.youtube.com/watch?v=0TvTyj5FAaQ


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AIDSis characterized by excessivelylow T lymphocytes

Red bone marrow producesmegakaryocytesthat fragment intoplatelets at a rate of about 150000-300000 a day

Twelve other clotting factorshelpplateletsform blood clotsThe Platelets and Blood Clotting

The plateletsand two plasma proteins, prothrombin and fibrinogen, function in bloodclotting, an enzymatic process that results in fibrin threads Trapped red blood cellsmake a clot appear red Serumcontains all the components of plasma except fibrinogen

YouTubevideo: How does blood clothttp://www.youtube.com/watch?v=--bZUeb83uU

The Platelets and Blood Clotting Hemophilia

Hemophiliais an inherited clotting disorder due to a deficiency in a clotting factorBone Marrow Stem Cells

Bone marrowis multi-potent, ableto continually give rise to particulartypes of blood cells

The skin and brain also have stemcells, and mesenchymal stem cellsgive rise to connective tissues

including heart muscle

Capillary Exchange

In a capillary, water moves out atthe arterial enddue to bloodpressure
http://www.youtube.com/watch?v=--bZUeb83uUhttp://www.youtube.com/watch?v=--bZUeb83uUhttp://www.youtube.com/watch?v=--bZUeb83uUhttp://www.youtube.com/watch?v=--bZUeb83uU


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At the venule endwater moves in due toosmotic pressure In between, nutrients diffuse out and wastes diffuse into the tissue fluid that bathe cells

QuestionsQ: What would the body do to adapt to living at a higher altitude, where oxygen isthinner?A:Additional red blood cells and capillaries are produced to carry additional oxygen.Furthermore, additional erythropoietin is produced by the kidney to increase blood cellproduction.

Q: What affect would carbon monoxide inhalation have on a person?A:Once carbon monoxide molecules would compete with oxygen when binding in the blood.Later, carbon monoxide would be transported by red blood cell through the lungs, the heart andblood vessels and into the systemic circuit. As a result, fewer oxygen molecules are carried by theblood which decreases the supply of oxygen for the body.

Q: What function do the following perform as elements of white blood cells?NeutrophilsEosinophilsBasophilsLymphocytesMonocytesWhich ones are granularand which ones are agranular, and what do these terms mean?*This is an important chart and you might want to memorize the function section of this chart.A:

Granular /Agranular

Type ofelements

Description Function

Granular

Neutrophils40-70%

10-14 in diameter.

Spherical cells with multipliednuclei; fine, pink granules in

cytoplasm

Phagocytize pathogens

Eosinophils1-4%

10-14 in diameter.Spherical cells with bilobednuclei; coarse, deep-red,

uniformly sized granules incytoplasm

Phagocytize antigen-antibody complexes and

allergens


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Basophils0-1%

10-12 in diameter.Spherical cells with lobednuclei; large, irregularly

shaped, deep-blue granules incytoplasm

Release histamine, whichpromotes blood flow to

injured tissues

Agranular

Lymphocytes

20-45%

5-17 in diameter. (average9-10 ) Spherical cells with

large, round nuclei.

Responsible for specific

immunity

Monocytes4-8%

10-24 in diameter. Largespherical cells with kidney-

shaped, round, or lobed nuclei

Become macrophages thatphagocytize pathogens and

cellular debris

Granular leukocyteare white blood cells with prominent granules in the cytoplasm. They arefilled with spheres that contain enzymes and proteins, which help white blood cells defend thebody against microbes. On the other hand, agranular leukocyteare white blood cells that doesnot contain distinctive granules. They are also called mononuclear cells, which typically have akidney-shaped or spherical nucleus.

Q: What does the enzyme plasmindo?A:Enzyme plasmindegrades many blood plasma proteins, including fibrin clots. In other words,it dissolves fibrin blood clots.

Q: What are stem cells, and what are a couple of examples of they might be used in thefuture for treatment of diseases?A: Stem cellsare cells that is ever capable of dividing and producing new cells that go on todifferentiate into particular types of cells. The bone marrow has multi-potent stem cells, whichhave the potential to give rise to other stem cells for the various formed elements.Usage: Bone marrow stem cells are able to differentiate into other types of cells, including liver,bone, fat, cartilage, heart, and even neurons. The possibility exists that a patients own bonemarrow stem cells could be used for curing certain conditions including diabetes, heart disease,liver disease, or even brain disorders (e.g., Alzheimer disease or Parkinson disease).

Q:What are two pressures involved in capillary walls, and what does each one do?A: Blood Pressure andOsmotic Pressureare involved in capillary walls. Blood Pressure causeswater to move from the blood to the tissue fluid, and the Osmotic Pressurecauses water tomove from the tissue fluid to the blood.

12.5 Cardiovascular DisordersAtherosclerosis

YouTubevideo: MEDICAL - How cholesterol clogs your arteries(atherosclerosis)http://www.youtube.com/watch?v=fLonh7ZesKsYouTube video: Artery Explorer http://www.youtube.com/watch?v=GBf59Z8tgA0

Atherosclerosisis due to a build-up of fatty material, mainly cholesterol, under the innerlining of arteries
http://www.youtube.com/watch?v=fLonh7ZesKshttp://www.youtube.com/watch?v=fLonh7ZesKshttp://www.youtube.com/watch?v=fLonh7ZesKshttp://www.youtube.com/watch?v=fLonh7ZesKs


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The deposits called plaque, can cause a clot (thrombus) to form, and can dislodge as anembolus and lead to thromboembolism

Stroke, Heart Attack, and AneurysmYouTube video: What causes a heart attack?http://www.youtube.com/watch?v=LA2DuxCcO4g

If a moving blood clot or embolus lodges in acerebral blood vessel or a cerebral blood vesselbursts, the blockage causes a stroketo occur, wherea portion of the brain dies

If a blood clot lodges in a coronary blood vessel, aheart attack occurs Partial blockage of a coronary artery causes anginapectoris An aneurysmis a ballooning of a blood vessel

Coronary Bypass Operations

Removing a segment of another blood vessel and replacing a clogged coronary artery is acommon operation

It may be possible to replace this surgery with gene therapy that causes new blood vesselsto grow where the heart needs more blood flow (see lower left diagram)


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Clearing Clogged Arteries

Angioplasty uses a long tube inserted through a vessel to this point where the artery orvein is blocked; inflating the tube may force the vessel open. (See upper right diagram)

Dissolving Blood Clots

Medical treatments for dissolving blood clotsinclude use of t-PA (tissue plasminogenactivator)that converts plasminogen intoplasmin, an enzyme that dissolves bloodclots, but can cause brain bleeding.

Aspirinreduces the stickiness of plateletsand reduces clot formation and risk for heartattack

Heart Transplants and Artificial Hearts

Heart transplantsare routinely performed but immunosuppressive drugs must be takenthereafter. There is a shortage of human organ donors. Work is currently underway toimprove an artificial heart, and muscle cell transplantmay someday be useful.

Hypertension

About 20% of Americans suffer from hypertensionor blood pressure higher than140/90.

The best defense against hypertension is regular check-ups and a life-style that lowers therisk of hypertension.


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Questions1) Name 5 different conditions/diseases that can affect the circulatory system and explain howeach one affect the circulatory system and what the possible consequences are for each one.

Conditions/diseases How does it affect? Possible consequences

Atherosclerosis

Fatty substances accumulate (as

plaques) abnormally beneath theinter-lining of the arteries leadingto the formation of a thrombus

and blocking an artery

Can lead to heart attack, stroke,

kidney disease, aortic aneurysm,angina pectoris, and so ondepending on artery.

Angina Pectoris

Condition characterized bythoracic pain resulting from

occluded coronary arteries; oftenprecedes a heart attack.

Squeezing or burning sensation inthe chest. It might lead to a heartattack if not cured.

Stroke

Condition resulting when anarteriole in the brain bursts or

becomes blocked by an embolus

(moving clot).

Lack of oxygen causes a portionof the brain to die, and paralysis

or death can result.

Heart Attack

Damage to the myocardium dueto blocked circulation in the

coronary arteries; also called amyocardial infraction.

A portion of the heart muscle diesdue to a lack of oxygen, and

death can result.

Aneurysm

Ballooning of a blood vessel, mostoften the abdominal artery or the

arteries leading to the brain. Itmight lead to burst of vessels.

If a major vessel such as the aortashould burst, death is likely.

Hypertension

Elevated blood pressure,particularly the diastolic pressure.It can be caused by narrowing ofarteries or unhealthy practices.

Addition blood pressure can

damage blood vessels, heart orother organs.

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Bio 12 Ch12 Cardiovascular Sys Notes Package