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Biology 235 > Chapter 20: The Cardiovascular System: The Heart > Flashcards

Chapter 20: The Cardiovascular System: The Heart Flashcards

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1
Q

Cardiology

A

The scientific study of the normal heart and the disease associated it.

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2
Q

Heart

A

Small, roughly the size as your closed fist.
Rests on the diaphragm, near the midline of the thoracic cavity.

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3
Q

Mediastinum

A

Where the heart lies.
An anatomical region that extends from the sternum to the vertebral column, first rib to the diaphragm and between the lungs.

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4
Q

Apex

A

Formed by the tip of the left ventricle and rests on the diaphragm.
Directly anteriorly, inferiorly and to the left.

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5
Q

Base of the Heart

A

Opposite the apex. Posterior aspect.
Formed by the atria of the heart, mostly the left atrium.

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6
Q

Anterior Surface

A

Deep to the sternum and ribs.

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7
Q

Inferior Surface

A

Part of the heart between the apex and the right surface and rests mostly on the diaphragm.

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8
Q

Right Surface

A

Faces the right lung and extends from, the inferior surface to the base.

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9
Q

Left Surface

A

Faces the left lung and externals from the base to the apex.

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10
Q

Pericardium

A

The membrane that surround and protects the heart.
Confines the heart to its position in the mediastinum.
Allows sufficient freedom of movement for vigorous and rapid contraction.
2 parts: fibrous and serous

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11
Q

Fibrous Pericardium

A

Main part of Pericardium: Superficial: prevents over stretching of the heart, protection and anchors it to the mediastinum.
Composed of tough, inelastic, dense irregular connective tissue.
Resembles a bag that rests on/attaches to the diaphragm.
Open end is fused to the CT of blood vessels entering and leaving the heart.

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12
Q

Serous Pericardium

A

Main part of pericardium: thinner, more delicate membrane.
Forms a double layer around the heart.
Outer Parietal layer: fused to the fibrous pericardium
Inner Visceral layer: (epicardium) adheres tightly to the surface of the heart.

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13
Q

Pericardial Fluid

A

Found between the parietal and visceral layer.
Slippery secretion of pericardial cells. Reduces friction between the layers of serous pericardium as the heart moves.

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14
Q

Pericardial Cavity

A

Space that contains the few millimeters of pericardial fluid.

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15
Q

Epicardium

A

Outer membrane layer of the heart. Composed of two tissue layers.
Outer layer is visceral layer, adheres to the surface of the heart.
Thin transparent layer, composed of mesothelium. Beneath mesothelium is fibroelastic and adipose tissue. Contains blood vessels, lymphatics and vessels that supplies the myocardium.

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16
Q

Myocardium

A

Middle layer of the heart
Responsible for the pumping action.
Contain muscle contractile fibers
Composed of cardiac (involuntary) muscle tissue. Makes up 95% of heart wall.
Muscle fibers are wrapped and bundled with CT sheaths composed of Endomysium and Perimysium.

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17
Q

Endocardium

A

Inner most layer of the heart
Thin layer of endothelium overlying thin layer of CT.
Provides smooth lining for chambers of the heart and covers valves.
The smooth lining minimizes the surface friction as blood passes through the heart.
Is continuous with endothelial lining of large vessels attached to the heart.

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18
Q

Chambers of the Heart

A

The heart contains 4 chambers.
Two superior receiving chambers: atria
Two inferior pumping chambers: ventricles

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19
Q

Atria

A

Two superior receiving chambers of the heart.
The paired atria receive blood from the blood vessels returning blood to the heart known as veins.

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20
Q

Ventricles

A

Two inferior pumping chambers.
Eject blood from the heart into blood vessels called arteries.

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21
Q

Auricle

A

Found on anterior surface of each atrium.
Wrinkles pouch like structure. Resembles a dogs ear.
Each auricle slightly increases the capacity of an atrium so that it can hold a breather volume of blood.

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22
Q

Sulci

A

Also on the surface of the heart.
A series of grooves. Contain coronary blood vessels and a variable amount of fat.
Each sulci marks the external boundary between 2 chambers of the heart.

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23
Q

Anterior Interventricular Sulcus

A

Shallow groove on the anterior surface of the heart.
Marks the external boundary between the right and let ventricles on anterior heart of the heart.

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24
Q

Posterior Interventricular Sulcus

A

Formed by the anterior sulus as it continues around to the posterior surface of the heart.
Marks the external boundary between the ventricles on the posterior aspect of the heart.

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25
Q

Veins

A

Always carry blood toward the heart.

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26
Q

Right Atrium

A

Thinned walled, allowing for it to deliver blood under less pressure. (About 2-3 mm in thickness)
Forms the right surface of the heart.
Receives blood from 3 veins:
1. superior vena cava
2. Inferior vena cava
3. Coronary sinus
Recieves deO2 blood through the superior and inferior vena cave. Blood passes through the tricuspid valve into the right ventricle.

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27
Q

Pectinate Muscles

A

Muscular ridges found in the anterior wall. Gives it a rough appearance.
Extend into the auricle

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28
Q

Interatrial Septum

A

Thin partition
Found between the right and left atrium.

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29
Q

Fossa Ovalis

A

Prominent feature of the interatrial spetum.
Oval depression.

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30
Q

Foramen Ovale

A

Remnant of the fossa ovalis
An opening in the interatrial septum of the fetal heart. Normally closes soon after birth.

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31
Q

Tricuspid Valve

A

Or right atrioventricular valve
valve where blood passes from the right atrium into the right ventricle.
Consists of 3 cusps or leaflets.

32
Q

Right Ventricle

A

Thicker walled due to having a thicker myocardium muscle layer. About 4-5 mm in thickness.
This is needed to eject blood at a higher pressure and at greater distances.
Forms most of the anterior surface of the heart.
Blood from the right ventricle passes through the pulmonary semilunar valve into the pulmonary trunk.

33
Q

Trabeculae Carneae

A

Series of ridges fromed by raised bundles of cardiac muscle fibers.
Contained inside the right ventricle.

34
Q

Chordae Tendineae

A

Tendonlike cords that connect the cusps of the tricuspid valve.
Function: prevent the AV valve from everting or Turing inside out while the heart is pumping blood.

35
Q

Papillary Muscles

A

Cone shaped trabeculae carneae that connect to chordae tendineae.

36
Q

Interventricular Spetum

A

Partition that separates the right and left ventricle.

37
Q

Pulmonary Valve

A

Where blood passes from the right ventricle into a large artery called the pulmonary trunk which divides into right and left pulmonary arteries and carries blood to the lungs.

38
Q

Arteries

A

Always takes blood away from the heart.

39
Q

Left Atrium

A

Thinned walled allowing it to deliver blood under less pressure (about 2-3 mm in thickness)
Contains a smooth posterior and anterior wall.
Forms most of the base of the heart.
Receives blood from the lungs through 4 pulmonary veins.
Recieves blood from the pulmonary veins. The O2 blood from the LA passes through the bicuspid valve (or mitral) into the left ventricle.

40
Q

Bicuspid Valve

A

Or mitral valve or left atrioventricular valve.
Where blood passes from the left atrium into the left ventricle.
Has two cusps.

41
Q

Left Ventricle

A

Thickest chamber of myocardium, 10-15 mm
Thickness is needed in order to eject blood at a higher pressure to greater distances out of the heart through the aorta. After leaving the LV, blood flows to coronary arteries which supple the surface of the heart.
Forms the apex of the heart.
Contains trabeculae carneae and chordae tendineae. These anchor the cusps of bicuspid valve to papillary muscles.
Blood from the LV passes through the aorta semilunar valve into the aorta.

42
Q

Aortic Valve

A

Where blood passes from the left ventricle into the ascending aorta.

43
Q

Ductus Arteriosus

A

Temporary blood vessel during fetal life.
Shunts blood from the pulmonary trunk into the aorta.
Hence only a small amount of blood enters the non functioning fetal lungs.

44
Q

Ligamentum Arteriosus

A

Remnant left after the ductus Arteriosus closed after birth.
Connects the arch of the aorta and pulmonary trunk.

45
Q

Myocardial Thickness

A

The thickness of the 4 chambers varies according to each chambers function.
Thin walled atria delivers blood under less pressure into the adjacent ventricles.
Thicker walled ventricles pump blood under higher pressure over greater distances.
Right side has a much smaller workload: pumps blood to lungs.
Left side pumps blood all over the body.

46
Q

Fibrous Skeleton of the Heart

A

Formed by dense CT.
Consists of 4 dense CT rings that surround the valves of the heart, fuse with one another and merge with the Interventricular septum.
Forms structural foundation
Prevents overstretching of the valves as blood passes through them

47
Q

Atrioventricular (AV) Valves

A

Tricuspid and bicuspid valve because they are located between an atrium and a ventricle.
When the AV valve is open, the rounded ends of the cusps project into the ventricle.
When ventricles and papillary muscles relax, the chordae tendineae are slack, blood moves from a higher pressure in the atria to a lower pressure in the ventricles through open AV valves. When the ventricles contact, the pressure of the blood drives the cusps upward until their edges meet and close the openings.

48
Q

Semilunar (SL) Valves

A

Aortic and pulmonary valves.
Located in both ventricles of the heart. During contraction of ventricles the valves open in response to increased pressure. As the ventricle relax, the semilunar valves close to prevent back flow.
Due to being made up of the 3 crescent moon shaped cusps.
Allows ejection of blood from the heart into arteries but prevent back flow of blood into the ventricles.

49
Q

Systemic Circulation

A

Left side of the heart pumps for this circulation. It receives bright red o2 blood from lungs. LV ejects blood into the aorta. From aorta, blood divides into separate streams, entering smaller systemic arteries that carry it to all organs thought the body.
Systemic Tissue arteries give rise to smaller arterioles which leads to extensive beds of systemic capillaries where gasses and nutrients pass. Blood uploads O2 and picks up CO2. Blood flows only through one capillary then to systemic venule. Venules carry deO2 blood away from tissue and merge to form larger systemic veins. Blood then glows back to right atrium.

50
Q

Pulmonary Circulation

A

Right side of the heart pumps for this circulation.
Receives dark red deO2 blood returning from systemic circulation. Blood ejects from the RV flows into pulmonary trunk, branches into pulmonary arteries that carry blood to the right and left lungs. Pulmonary capillaries unload CO2 which is exhaled and picks up O2 from inhaled air. The fresh O2 blood then flows into pulmonary veins and returns to the LA.

51
Q

Coronary Circulation (Vessels)

A

Apart of the Myocardium network of blood vessels. This is because nutrients are not able to diffuse quickly enough from blood in the chambers of the heart to supply all layers of cells that make up the heart.
When heart is in diastole (relaxation) blood flows into coronary vessels.
When heart is in systole (contraction) blood is prevent from flowing into coronary vessels.

52
Q

Coronary Arteries

A

In coronary circulation these arteries branch from the ascending aorta and encircle the heart like a crown encircles the head. While the heart contracts little blood flows in the coronary arteries because they are squeezed shut.

53
Q

Coronary Veins

A

In coronary circulation while the heart relaxes, the higher pressure of blood in the aorta pumps blood through the coronary arteries, into capillaries and then into coronary veins.

54
Q

Left Coronary Artery

A

The left coronary artery passes inferior to the left auricle and divides into the anterior Interventricular and circumflex branches. The anterior interventrcular branch is in the anterior Interventricular sulcus and supplies O2 blood to the walls of both ventricles. The circumflex branch lies in the coronary sulcus and distributes O2 blood to the walls of the LV and LA.

55
Q

Right Coronary Artery

A

Supplies small branches to the RA. Continues inferior to the right auricle and divides into posterior Interventricular and marginal branches. The posterior Interventricular branch follows the posterior Interventricular sulcus and supplies the walls if two ventricles with O2 blood. The marginal branch beyond the coronary sulus runs along the right margin of the heart and transport O2 blood to the wall of the RV.

56
Q

Anastomoses

A

Where 2 or more arteries supply the same region, they connect.

57
Q

Collateral Circulation

A

Where anastomoses connections provide alternate routes for blood to reach a particular organ or tissue.

58
Q

History of Cardiac Muscle Tissue

A

Cardiac muscle is shorter in length and less circular in transverse section.
Exhibit branching, gives the muscle fiver a “stair step” appearance.
50-10 um long and 14 um diameter.
One nucleus present.

59
Q

Intercalated Discs

A

Where the ends of cardiac muscle fibers connect to neighboring fibers by irregular transverse thickening of sarcolemma.

60
Q

Desmosomes

A

Contained in Intercalated discs. Hold fibers together.

61
Q

Gap Junctions

A

Allows muscle action potentials to conduct from one muscle fiber to its neighbors. Allow the entire myocardium of the atria or the ventricles to contract as a single coordinated unit.

62
Q

Refractory Period

A

The time interval during which a. Second contraction cannot be triggered.
Of a cardiac muscle fibers last longer than the contraction itself.

63
Q

ATP Production in Cardiac Muscle

A

Cardiac muscle produces little of the ATP it needs by anaerobic cellular respiration
Instead relies on exclusively on aerobic cellular respiration in the numerous mitochondria.
The needed O2 diffuses from blood in the coronary circulation and is released from myoglobin inside cardiac muscle fibers.
Cardiac muscle also produces ATP from creatine phosphate.

64
Q

Electrocardiogram of Cardiac Cycle

A

ECG or EKG
Recording of electrical signs that are action potentials that propagate through the heart as they generate electrical currents that can be detected at the surface of the body.
P wave: atrial systole occurs (contraction)
QRS complex: represents rapid ventricular depolarization. Atrial diastole (relaxation) occurs simultaneously with QRS complex.
Shortly after this complex occurs: ventricle systole occurs (contraction).
T wave: ventricular diastole (relaxation) occurs

65
Q

Electrocardiograph

A

Amplifies the hearts electrical signals and produces a 12 different tracings from chest and limb leads.
By comparing these records with one another with normal records it is possible to determine:
1. If the conducting pathway is abnormal
2. If the heart is enlarged
3. If certain regions of the heart are damaged
4. The cause of chest pain.

66
Q

P Wave

A

First recognizable wave of each heart beat.
Is a small upward deflection on the ECG.
Represent atrial depolarization which spread from the SA node through contractile fibers in both atrial.

67
Q

QRS Complex

A

The second wave. Begins as a downward deflection, continues as a large, upright, traigular wave, and ends as a downward wave.
Represents rapid ventricular depolarization as action potential spreads through ventricular contractile fibers.

68
Q

Totals Blood Voulme

A

5 Litres in adult male.
Blood circulates throughout your pulmonary and systemic circulations every 1 min.
Stoke volume: 70 mL/beat
Heart Rate: 75 beats/min

69
Q

Cardiac Action Potential:Contractile Fibers

A

Resting Membrane Potential: 90mV
The SA noise initiates an action potential that will propagate through the conduction system to trigger a contraction.
Depolarization phase: contractile fibers are stable (90mV). Voltage gated fast Na+ channels open. Inflow of Na makes it more neg produce rapid depolarization.Within a few secs, Na auto inactivate and Na flow decreases.
Plateau Phase: Maintained depolarization occurs due to the opening of voltage coated slow Cs2+ channels. When open Ca2+ moves from interstitial fluid into the cytosol. The increased amount of Ca2+ triggers contraction.
Voltage gated K+ ion channels open just before the plateau phase begin allowing for K+ to leave the contractile fibers. This action contributes to continued depolarization: Ca2+ inflows balances K+ outflow.
Repolarization: recovery of resting potential. After delay more voltage gated K+ channels open. Outflow of K restores negative resting potential of 90 mV.

70
Q

Conduction System: Propagate Cardiac Action Potential

A

Begins at: SA Node (located in R atrial wall). SA do not have a stable resting potential so they repeatedly depolarize knowing as pacemaker potential.
When threshold is reached triggers: action potential
From SA node to atria via jap junctions in intercalated discs.
Following action potential, 2 atria contract simultaneously.
Moves to: atrioventricular node (AV) (located in inreratrial septum). Here is slows or delays due to difference in cell structure of AV node. Delay allows for atria to empty blood into ventricles.
From AV node, AP enter atrioventricular (AV) bundle. Site where AP can conduct the atria to ventricles.
After AV bundle: AP enters right and left bundle brands through interventricular spectrum towards apex.
Finally to Purkinje fibers. Conduct AP to apex then up to ventricular myocardium then up to SL valves.

71
Q

Vagus Nerve (X)

A

This nerve carry parasympathetic nerve impulses to the heart. The axons of the nerve releases acetylcholine which slows depolariazation in cardiac fivers which decrease the heart rate.
If this nerve was cut or severed the impulses could not reach the heart causes increased heart rate.

72
Q

Coronary Sinus

A

Large vascular sinus.
Tributary that supplies this sinus: great cardiac vein, middle cardiac vein, small cardiac vein.
Located on the posterior surface of the heart.

73
Q

Heat Sounds

A

S1: lubb sound. Turbulence caused by closure of AV valves
S2: dubb sound. Turbulence cause by closure of SL valves at beginning of ventricular diastole (relaxation).
S3 and S4: not loud enough to hear. Turbulence associated with rapid ventricular filling and atrial systole (contraction).

74
Q

When Heart Rate exceed 160 BPM

A

All occur:
Preload is lower
Stroke volume is lower
End diastole volume decreases

75
Q

Cardiovascular Center

A

Autonomic regulation of the heart rate is control by this center located in the medulla Oblongata.
Sensory input receives from higher brain centers, processed nerve impulses are sent back to SA node and AV node and myocardium via cardiac accelerator nerves.
Cardiac accelerator nerves trigger the releases of norepinephrine.

Biology 235 (29 decks)

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