Lesson 18- Heart
Health And Exercise Science 027 with Kennithmobily at University of Iowa
About this deck
By: Stephanie Baer
Created: 2010-11-26
Size: 64 flashcards
Views: 29
Created: 2010-11-26
Size: 64 flashcards
Views: 29
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Functions of Circulatory system
-includes fluids, solid elements, tubes & a pump
-transport gases and nutrients & waste products
-carries hormones to target cells rapidly
-Because of WBC (Leukocytes) & platelets (essential for clotting) in the blood, circulatory system plays important roles in defense of the body
-immune response, clotting.
Pulmonary Circuit
- formed by blood vessels that carry blood to and from the lungs
-Right side of the heart is the PULMONARY PUMP= propels oxygen poor blood to the lungs to pick up oxygen
Systemic Circuit
-formed by blood vessels that transport blood to and from all body tissues
-Left side of the heart is SYSTEMIC PUMP= pumps oxygen rich blood to tissues throughout the body
Atrium
-2 receiving chambers Right & left atriums
-"entranceway"
-receive blood returning from the systemic & pulmonary circuits.
Ventricle
-two main pumping chambers of the heart, right & left ventricle, pump blood around the two circuits.
-"hollow belly"
-Most of right ventricle is seen in an anterior view of the heart
-Left ventricle= Largest chamber= makes up most of the left, inferior/posterior surface of the heart.
Location of Heart in Mediastinum (the organs between the pleural cavities)
-Medial to each lung
-anterior to vertebral column
-posterior to sternum
-slightly off center to the left
-Lies somewhat on its right side
-terminates inferiorly in an APEX that is directed downward & to the left
-Apex contacts the thoracic wall between the 5th & 6th ribs just inferior to the left nipple
-the hearts base is its broad posterior surface
Pericardium
-a triple-layered sac that encloses the heart
1. Fibrous pericardium
2. Serous pericardium ( deep to fibrous)
-Parietal layer of serous pericardium
-visceral layer of the serous pericardium
3. Pericardial Cavity
Fibrous pericardium
- The outer layer of pericardium
-strong layer of dense connective tissue
-adheres to the diaphragm inferiorly
-superiorly its fused to the rots of the great vessels that leave and enter the heart
-tough outer coat that holds the heart in place & keeps from overfilling w/ blood
Serous Pericardium
- Deep to fibrous
-double layered
-a closed sac between the fibrous pericardium & heart
- Parietal layer of Serious peri= outer layer, adheres to the inner surface of the fibrous pericardium= it is continuous w/ Serous pericardium (epicardium)
Epicardium= lies on the heart & is considered a part o the heart wall.
Pericardial Cavity
-a silt-like space between the parietal & visceral layers of serous pericardium.
-epithelial cells of serous pericardium line the cavity
-cells secrete a lubricating film of serous fluid into the cavity
-fluid reduces friction between the beating heart & outer wall of pericardial sac
-a division of the embryonic coelom that separates the inner tube from the outer tube.
Layers of Heart Wall
Epicardium= superficial
Myocardium= middle
endocardium= deep
-all 3 layers are richly supplied w/ blood vessels
Epicardium
-"upon the heart"
-Visceral layer of serous pericardium -serous membrane is often infiltrated w/ fat *esp. w/ old people
Myocardium
-"muscle heart"
-forms the bulk of the heart
- consists of cardiac muscle tissue
-is the layer that actually contracts
-connective tissues surround the cardiac muscle cells & bind cells together into elongated circular & spirally arranged networks called BUNDLES
Bundles
-squeeze blood through the heart in proper directions:
inferiorly= through the atria
superiorly= through ventricles
Fibrous skeleton of heart
-formed by connective tissues of myocardium
-reinforces myocardium internally
Functions:
1. anchors the valve cusps
2. prevents over-dilation of the valve openings as blood pulses through them
3. the point of insertion for the bundles of cardiac muscle in the atria and ventricles
4. blocks the direct spread of electrical impulses from the atria to the ventricles.
*function is critical for proper coordination of atrial and ventricular contractions
Endocardium
-"inside of heart"
-located deep to myocardium
-is a sheet of endothelium resting on a thin layer of connective tissues
-lines heart chambers and covers the heart valves
Interatrial septum
-wall between the atria
Interventricular septum
- wall between the ventricles
Sulic
-externally marks the boundaries of the 4 chambers
2 grooves:
1. conary sulcus
2. anterior interventricular sulcus & posterior interventricular sulcus
Cornary sulcus
-forms a crown by circling the boundary between the atria & ventricles
Interventricular Sulcus
- marks the anterior position of the inter ventricular septum between the 2 ventricles
Posterior interventricular Sulcus
-separates the 2 ventricles on the hearts inferior surface
Chambers of the heart
Right Atrium = forms entire right border of human heart
Right Ventricle=forms most of the anterior surface of the heart
Left atrium= makes up most of hearts posterior surface or base
Left Ventricle = forms the apex of heart & dominates hearts inferior surface
Right Atrium
-the receiving chamber for oxygen poor blood returning from systemic circuit
-Receives blood via 3 veins:
-superior vena cava
-inferior vena cava
-coronary sinus
-communicates w/ right ventricle through:
TRICUSPID VALVE (right atrioventricular valve) =
-inferiorly & anteriorly atrium opens up into right ventricle through this valve
-Prevents regurgitation of blood from ventricles back into atria when ventricles contract
Right atrium anatomy
externally:
RIGHT AURICLE=small flap shaped like dogs ear
-projects anteriorly from superior corner of atrium
Internally:
-Pectinate Muscles= horizontal ridges that line the smooth-walled anterior & posterior part.
-Crista Terminalis=
Separates two parts of the atrium
-large C-shaped ridge
Fossa Ovalis= a depression in the interatrial septum that marks the spot where an opening existed in fetal heart.
Right atrium anatomy ( veins)
-SUPERIOR VENA CAVA=
-opens into atrium just posterior to the superior bend of the crista
-blood from body regions superior to diaphragm excluding the heart wall
-INFERIOR VENA CAVA= opens into atrium just posterior to inferior bend of crista
-blood from body regions inferior to diaphragm
-CORONARY SINUS= opens into atrium anterior to the inferior end of the crista
-blood draining from the heart wall itself is collected and enters
Right ventricle
-forms most anterior surface of heart
- receives blood from right atrium and pumps it into the the pulmary circuit via PULMONARY TRUNK (an artery)
Internally=
TRabeculae Carneae= irregular ridges of muscles that mark the ventricular walls
PAPILLARY MUSCLES= project from walls into the ventricular cavity and connect to the R. atrioventricular valve Via. CHORDAE TENDINEAE (tendinous cords)
Pulmonary Valve= Superiorly the opening between the right ventricle & pulmonary trunk contains it.
Left Atrium
-most of hearts posterior surface/base
-receives oxygen rich blood returning from lungs through 2 Right & 2 Left PULMONARY VEINS.
-only part that is visible anteriorly is triangular left auricle
-Internally= most of wall is smooth w/ pectinate muscles lining Auricle only
-Opens into left ventricle through MITRAL VALVE ( LEFT ANTRIOVENTRICULAR VALVE.)
Left Ventricle
-forms APEX of heart & dominates hearts inferior surface
-pumps blood Into the systemic circuit
-thicker wall than r. ventricle
-like R. ventricle it contains= trabeculae carneae, papillary muscles, cordae tendineae & cusps of MITRAL VALVE.
-superiorly it opens into the stem artery of the systemic circulation ( the aorta) through the AORTIC VALVE.
-thick wall gives the camber a circular shape and flattens the r. ventricle into a crescent shape.
Tricuspid Valve
-R. atrioventricular valve
-enforce one-way flow of blood through heart from R. atria to R. ventricle
-has 3 cusps
-
Mitral Valve
-Left atrioventricular valve
-enforce one way blood flow from L. Atria to L ventricle
-2 cusps
Blood entrance to the R. atrium
Blood from body regions above diaphragm enters R. atrium through SVC
Blood from body regions below diaphragm enters R. Atrium through IVC
Blood draining from walls of the heart enters through coronary sinus
blood pathway pre pulmonary circuit
-Blood passes from R. atrium through TRICUSPID valve to the r. ventricle
**propelled by gravity & contraction of R atrium
-R. ventricle contracts= propells blood through the PULMONARY SEMILUNAR VALVE into=
1. Pulmonary trunk &
2. lungs through the pulmonary circuit for oxygenation
blood pathway post Pulmonary circuit
- Oxygenated blood returns via 4 pulmonary veins to the left atrium
-passes through Mitral valve to the left ventricle
*propelled by gravity & contraction of L. atrium
-L. ventricle contracts and propels blood through AORTIC SEMILUNAR VALVE into AORTA & its branches
-After delivering oxygen and nutrients to the body tissues through the SYSTEMIC CAPILLARIES, the oxygen poor blood returns through the systemic veins to the right Atrium
Contraction cycles of chambers
Atriums always contract together followed by the simultaneous contraction of the two ventricles
Heart beat
- a single sequence of atrial contraction followed by ventricular contraction
-heart of average person beats 70-80 times per minute
-systole & diastole
-commonly used to refer to the stages of the heartbeat when the VENTRICLES (the dominant heart chambers are contacting & filling respectively
Systole
-The term that describes the contraction of a heart chamber
Diastole
- the time during which a heart chamber is relaxing and filling w/ blood
Anatomical differences in heart chambers
-Walls of atria= much thinner than walls of ventricles
* gravity helps pump blood through to ventricles so little strength is required
L. Ventricle (systemic pump)= at least 3 times thicker then R. ventricle (pulmonary pump)
*** L. ventricle can generate much more force than right & pumps blood @ much higher pressure
-Systemic circuit= much longer than pulmonary circuit= offers much greater resistance to blood flow
Atrioventricular valves
-present back flow of blood into the atria during contraction of the ventricles
-when ventricles are diastole = cusps of AV valves hang limply into the ventricular chambers as blood flows into the atria and down through the open AV valves into the ventricles
-when ventricles contract= pressure w/in them rises and forces blood superiorly again valve cusps=pushing AV cusps together and closing the AV valves
AV valves cont.
chordae tendineae & papillary muscles= look like cords of parachute= limits the closed cusps so they cant fly up and allow reflux of ventricular blood into atria
-papillary muscles begin to contract slightly b4 the rest= pulls on chordae tendineae & prevent AV valves from everting
Semilunar valves
-prevent back flow from great arteries into the ventricles
-when ventricle contract & raise intraventricular pressure= the semilunar valves are forced 2 open & cusps are flattened against arterial walls as blood rushes past them
-when ventricles relax blood that tends to flow back toward the heart fills the cusps of the semilunar valves and forces them shut .
-Pulmonary semilunar = on right
-aortic semilunar= on left
Origin of heart beat
-heart is intrinsic= heartbeat arises from a structure located inside the heart itself
- does not need extrinsic nerve impulses
-"Pacemaker"= SINOATRIAL (SA) node. = crescent shaped mass of muscle cells that lies in the wall of R. atrium, just inferior to entrance of SVC
-signal initiated by the SA NODE, spreads throughout the myocardium through the gap junctions in the intercalated discs
conducting system
-a series of specialized cardiac muscle cells that carries impulses through out the heart musculature= signals heart chambers to contract in proper sequence
-also initiates each contraction sequence= sets basic heart beat
Components of system=
-sinoatrial node
- internodal fibers
-atrioventricular node, atrioventricular bundle
- right & left bundle branches,
-subendocardial branches (purkinje fibers)
impulse of heart beat
- impulse that signals begins at sinoatrial node (SA)
-spreads through the myocardium through gap junctions in the intercalated discs=signals atria to contract
travel along INTERNODAL PATHWAY
INTERNODAL PATHWAY
- Sa node impulses spread in a wave along cardiac muscle fibers of the atria= signals atria to contract
-impulses travel along internodal pathway to AV node= in inferior part of interatrial septum = delay for 1/2 a second
-after delay impulses race through the atrioventricular bundle
-which enters the interventricular septum & divides R. & L bundle branches (crura)
-1/2 way down septum=the crura become purkinje fibers=which approach APex & turn superior in 2 ventricular walls
Internodal pathway
-arrangement ensures that contraction of ventricles begins @ apex of heart and travels superiorly = ventricular blood is ejected superiorly into great arteries
-brief pause at AV node enables ventricles to fill completely before they contract
- fibrous skeleton between atria and ventricles is nonconducting= prevents impulses in the atria from proceeding directly to ventricle wall = only signals that go through the node can continue
-suggests that atria contract from TOP DOWN & vent. BOTTOM UP
ANS
-Innervates heart & can cause it
1. to increase rate and strength of contraction (sympathetic)
2. decrease rate of contraction (parasympathetic)
-ANS simulation is controlled by centers in the medulla
-Cardioacceleratory center= increase the rate and strength of heart's contractions through sympathetic division of ANS
Parasympathetic
- nerves arise as branches of VAGUS NERVE in neck & thorax
-influences heart rate
-restricted to SA & AV nodes & the coronary arteries
CARDIOINHIBITORY CENTER = in medulla= influences parasympathetic neurons
sympathetic
-nerves travel to heart from cervical & upper thoracic chain ganglia
-innervate SA & VA nodes, coronary arteries & project to the cardiac musculature through out the heart
-effect both rate & strength of contractions
-CARDIOACCELERATORY CENTER= in medulla= influences sympathetic neurons
Nerves to the heart
* all nerves entering the heart pass through the cardiac plexus on the trachea before entering the heart
-nerves to the heart=
-visceral sensory fibers
-parasympathetic fibers= slow heart rate
-sympathetic fibers= increase heart rate & force of cntractions
coronary artery
-blood supply to the muscular walls & tissues
-arise from base of aorta & run in coronary sulcus
Left & right Coronary artery
-arrangement of coronary arteries varies among individuals,
Left coronary artery
-arises from left side of aorta
-passes posterior to the pulmonary trunk & then divides into 2 branches
1. anterior inter ventricular artery= descends in anterior inter ventricular sulcus toward apex, sending branches onto the inter ventricular septum & onto anterior walls of both ventricles
2. circumflex artery= follows coronary sulcus posteriorly & supplies the left atrium & posterior part of left ventricle
Right coronary artery
-emerges from right side of aorta & descends in the coronary sulcus on the anterior surface of the heart (between R. atrium & R. ventricle )
Marginal artery= @ inferior border of heart R. corn. art. branches into marginal artery
-continuing to posterior part of coronary sulcus the R. corn. ARt gives off a large branch called:
Posterior interventricular artery= in posterior interventricular sulcus
- branches of R. cor.art supply right atrium and almost all of r.. ventricle
Cardiac veins
-carry deoxygenated blood from heart wall into right atrium
-occupy the sulci on heart surface
Coronary sinus= largest, occupies posterior part of coronary sulcus returns all the venous blood to the atrium
3 large Tributaries drain into the coronary sinus
1. great cardiac vein=in anterior interventricular sulcus
2. middle cardiac Vein= in posterior interventricular sulcus
3. Small cardiac vein= running along hearts inferior right margin
ANTERIOR CARDIAC VEINS
- veins that lie on the anterior surface of the right ventricle
-horizontal veins that empty directly into the right atrium
Risk factors for cardio-vascular disease
- heart-attacks are one of the leading causes of death
-some people are predisposed to heart attacks
-mostly lifestyle risk factors that account for manifestation of a heart attack=
-excess weight
-hypertension (high blood pressure)
-excess saturated fats in the diet
-smoking
-diabetes mellitus
-lack of regular exercise
Congestive heart failure
-"dilated cardiomyopathy"
- the heart enlarges greatly while its pumping efficiency progressively declines
-its cause is unknown
- 1 hypothesis= may involve a destructive positive feed back loop: an initially weakened heart causes the sympathetic nervous system to stimulate the heart to pump harder
-increased demand further weakens the heart which again stimulates the SNS.
Angina pectoris
-thoracic pain caused by inadequate oxygenation of the heart muscle cells, which weaken but don't die
-can result from tissue Hypoxia, or stress induced spasms of atherosclerotic coronary arteries
-attacks during exercise when vigorously contracting heart may demand more oxygen than the narrow coronary arteries can deliver
-and onset of angina should be considered a warning sign of other more serious conditions
myocardial infraction
-if blockage of coronary artery is more complete or prolonged= oxygen starved cardiac muscle cells die= myocardial infraction= heart attack
-sharp pain strikes through chest & sometimes left arm, and left side of neck & does not subside
-death from cardiac arrest occurs almost immediately (1/3 of cases)
-Heart attacks kill :
- Directly = severe weakening of the heart
-indirectly =due to heart-rhythm disruptions caused by damage to the conducting system
-damage is irreversible
ischemia
- a condition where blood flow to the heart is interrupted often, just like w/ angina but w/ out any pain to provide warning.
-can be detected by measuring heart rhythm through electrocardiography (ECG) during exercise "treadmill test. "
Heart Block
-damage to the AV node or AV bundle B/c its the only route for impulse transmission from the atria to ventricles
-interferes w/ the ability of the ventricles to receive the pacing impulses
-w/ out the signals the ventricles beat @ a intrinsic rate that is slower than that of atria & too slow for adequate circulation
-artificial pacemaker that is set to discharge the appropriate rate is implanted.
Incompetent Valve
-Valves that leak b/c they fail to close properly
-exhibit insufficiency
-produces a distinct blowing sound after the valve closes
-lessens heart efficiency= increases its workload
-weakens heart severely
stenotic valve
-valves w/ narrowed openings
-occurs when cusps have fused or become stiffened by calcium deposits
-stiffened valves can't open properly
-stenosis of aortic valve produces a distinctive "click" sound during ventricular systole as blood passing through the constricted opening becomes turbulent and vibrates
-lessens the hearts efficiency and increases its workload
-ultimately weakens heart severely
About this deck
By: Stephanie Baer
Created: 2010-11-26
Size: 64 flashcards
Views: 29
Created: 2010-11-26
Size: 64 flashcards
Views: 29
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
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