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anatomy > Chapter 19 & 20; the heart and circulatory system > Flashcards

Chapter 19 & 20; the heart and circulatory system Flashcards

1
Q

where is the heart located in the body and what protects it?

A

located in the thoracic cavity and protected by the pericardium

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2
Q

what is the fibrous pericardium and what is it made of

A

outer layer, made of dense regular CT

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3
Q

what is the serous pericardium

A

double layered, pericardial fluid-filled membrane

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4
Q

what is the parietal layer of the serous membrane?

what is the visceral layer of the serous membrane?

which layer contains serous fluid and what does it do?

A

the outermost layer; in contact with the fibrous pericardium

surrounds and is continuous with the surface of the heart; layer that touches the heart

the serous pericardium; provides lubrication between the two serous membranes

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5
Q

what are the layers of the heart from outermost to innermost

A

epicardium, myocardium, endocardium

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6
Q

what is the epicardium

what is the myocardium

what is the endocardium

A

outermost layer of the heart, made of simple squamous epithelia, loose areolar CT, and adipose tissue

thickest layer, contains cardiomyocytes and cardiac muscle

deepest layer, made of simple squamous endothelial tissue

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7
Q

How many chambers does the heart have?

A

4; two upper chambers (atria), and two lower chambers (ventricles)

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8
Q

what separates the left and right side of the heart?

what makes up the systemic pump, what does it do?

what makes up the pulmonary pump, what does it do?

A

the cardiac septum

the left atrium and the left ventricle; pumps oxygenated blood to tissues

the right atrium and the left ventricle; pumps deoxygenated blood to the lungs

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9
Q

valves create ____

which valves separate the atrium from the ventricles?

what are cusps

what are the semilunar valves (SL); where are they located; what do they do

what is the chordae tendinae

A

one-directional blood flow

the atrioventricular valves (AV); the tricuspid valve and the bicuspid valve

flaps anchored to the cardiac skeleton

Aortic and pulmonary valves; located between the ventricles and major blood vessels; prevent backflow into the ventricles

anchors cusps to papillary muscles and prevents eversion

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9
Q

what are the two major divisions of the circulatory system

A

pulmonary (right side) and systemic circulation (left side)

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9
Q

describe the levels of blood flow through the heart and major vessels (6)

A
  • deoxygenated blood enters the right atrium from the body via the superior and inferior vena cava
  • blood is pumped through the tricuspid valve to the right ventricle
  • blood exits the heart through the pulmonary arteries and into the pulmonary circulation
  • oxygen-rich blood returns through the pulmonary veins and into the left atrium
  • blood is pumped through the mitral valve and into the left ventricle
  • blood exits the heart through the aorta into systemic circulation
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9
Q

describe pulmonary circulation

A
  • deoxygenated blood is carried from the right side of the heart to the lungs
  • at the lungs, blood picks up oxygen and releases carbon dioxide
  • blood vessels return blood to the left side of the heart
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9
Q

describe systemic circulation

A
  • oxygenated blood from the left side of the heart is delivered to systemic cells (tissues of the body)
  • at systemic cells (ex skin, muscles), blood exchanges gases nutrients, and wastes
  • blood vessels return blood to the right side of the heart
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10
Q

describe contraction

describe relaxation

A
  • decreases chamber volume; increases chamber pressure
  • increase chamber volume; decreases chamber pressure
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10
Q

describe the coordination of the beating heart (4)

A
  • pulmonary and systemic pumps work in parallel and beat simultaneously
  • they are connected and highly coordinated
  • contract and relax together
  • pump roughly the same volume of blood
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10
Q

what are the fetal shunts to blood flow during fetal development? describe them

A
  • Foramen ovale: a small hole that allows blood to bypass the right ventricle, moving directly between the right and left atrium
  • Ductus arteriosus: connects the pulmonary trunk to the aorta
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11
Q

features of cardiac muscle; cardiomyocytes (11)

A
  • single, central nucleus
  • short and wide
  • myofilaments arranged in sarcomeres
  • striations
  • myofibrils are branched and range in size
  • great abundance of mitochondria
  • resist fatigue through aerobic metabolism
  • die without O2
  • sarcoplasmic reticulum lacks cisternae
  • fused membranes, intercalated discs
  • entire tissue functions together; autorhythmic
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12
Q

heart contraction involves two events, what are they and what do they do?

when does this process occur

A
  1. the conduction system initiates and propagates an action potential
  2. cardiac muscle cells initiate action potentials and contract
  • this process happens first in the atria and then the ventricles
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13
Q

what features are involved in the hearts conduction system (4)

A

sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular (AV) bundle, Purkinje fibers

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14
Q

what does the SA node do; where is it located

where is the AV node located

what does the AV bundle do

what do the purkinje fibers do

A
  • pacemaker; initiates heartbeat; located high in posterior wall of right atrium
  • in the floor of the right atrium near the right AV valve
  • bundle of His; extends from the AV node through the interventricular septum and divides into left and right bundles
  • they extend form left and right bundles at the hearts apex; course through the walls of the ventricles
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14
Q

two simple steps of the conduction system

A

Initiation > SA node initiates action potential

Spread of action potential > AP is propagated throughout the atria and the conduction system until it reaches the ventricles

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14
Q

what is RMP

A

resting membrane potential, typically -90 mV

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15
Q

describe steps 1-3 of action potential in contractile cardiomyocytes

A
  • voltage-gated channels are closed when at rest, leaky K channels maintain general RMP
  • depolarization from the conduction system opens fast voltage-gated Na channels, depolarizes to -30 mV
  • depolarization causes K and Ca channels to open, K leaves, Ca comes in, plateau effect
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15
Q

what is step 4 of the movement of action potential

A

Rapid repolarization > calcium channels close, K channels remain open. Membrane potential repolarizes to resting state

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15
Q

Depolarization moves _____ through the ventricular conducting system to the ____. This ensures blood is efficiently ejected _____ to the vessels.

A

rapidly; apex; upward

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15
Q

__________ events make the atria contract simultaneously, and the ventricles contract _______________.

A

Depolarization; simultaneously

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16
Q

What does an electrocardiogram (ECG) provide and how (4)

A
  • common diagnostic tool
  • electrical picture of the heart using waves
  • obtained through electrodes/leads placed on the surface of the skin
  • summary of electrical changes taking place within all cells of an entire organ
16
Q

what is a P wave

what is a T wave

A
  • reflects electrical changes in atrial depolarization originating in the SA node
  • electrical change associated with ventricular repolarization
17
Q

what is the driving force of the cardiac cycle?

how does ventricular contraction raise ventricular pressure?

how does ventricular relaxation lower pressure?

A
  • ventricular activity
  • AV valves are pushed closed, semilunar valves are pushed open and blood is ejected to the artery
  • semilunar valves are closed due to no pressure from below, AV valves open due to no pressure keeping them closed
17
Q

what is the QRS complex

A
  • electrical changes associated with ventricular depolarization
  • atria also simultaneously repolarizing
18
Q

what is the cardiac cycle?
what does it include?

A
  • all events in the heart from the start of one heart beat to the start of the next
  • includes both systole (contraction) and diastole (relaxation)
19
Q

blood moves ____ its pressure gradient

valves ensure

A
  • down (high to low)
  • that flow is forward (no backflow)
20
Q

describe atrial systole
corresponds to-
atrial pressure-
AV valves-
ventricular blood volume-

A
  • corresponds with contraction of the atria
  • atrial pressure: greater than the ventricle
  • AV valves: open
  • ventricles: blood volume increasing, eventually reaching max (end-diastolic volume, EDV)
21
Q

describe early ventricular systole
corresponds to-
ventricular pressure-
blood volume-
AV valves-
SL valves-

A
  • corresponds with contraction of the ventricles
  • ventricular pressure: greater than atria, less than great vessels
  • blood volume: constant at EDV
  • AV valves: closed
  • SL valves: closed
22
Q

describe late ventricular systole:
ventricular pressure-
blood volume-
AV valves-
SL valves-

A
  • ventricular pressure: greater than atria, greater than great vessels
  • blood volume: decreasing
  • AV valves: closed
  • SL valves: open
23
Q

describe early ventricular diastole:
corresponds to-
ventricular pressure-
blood volume-
AV valves-
SL valves-

A
  • corresponds to relaxation in ventricles
  • ventricular pressure: greater than atria, less than great vessels
  • blood volume: constant
  • AV valves: closed
  • SL valves: closed
23
Q

describe atrial diastole:
atrial pressure-
ventricular blood volume-
AV valves-

A
  • atrial pressure: less than ventricles
  • ventricular blood volume: increasing
  • AV valves: open
24
Q

describe late ventricular diastole:
ventricular pressure-
ventricular blood volume-
AV valves-
SL valves-

A
  • ventricular pressure: less than atria, less than great vessels
  • ventricular blood volume: increasing through passive filing
  • AV valves: open
  • SL valves: closed
25
Q

what are the 3 types of blood vessels

A

arteries, capillaries, veins

25
Q

what are arteries

what are capillaries

what are veins

A
  • convey blood from heart to capillaries
  • microscopic porous blood vessels; exchange substances between blood and tissues
  • transport blood from capillaries to heart
26
Q

what are the 3 layers of blood vessels

A

tunica intima, tunica media, tunica externa

27
Q

Describe an artery compared to a vein?
Why do arteries contain more elastin and collagen fibers?

A
  • have thicker walls and smaller lumens than veins
  • need to handle larger amounts of pressure from the heart
27
Q

tunica intima?

tunica media?

tunica externa?

A

> innermost layer of BV containing endothelium: simple squamous epithelia

> middle layer contains smooth muscle fibers that are responsible for vasoconstriction and vasodilation

> outermost layer made of CT that stabilizes blood vessels

27
Q

describe elastic arteries?
AKA?
EXs?

A
  • large volume of elastin dispersed; large lumens to hold lots of blood
  • AKA conducting arteries
  • includes the aorta and vessels that branch off of the arch
28
Q

muscular arteries AKA?
2 prominet bands?
Ex ?

A
  • AKA distributing arteries
  • have two prominent bands of elastic tissue > internal and external elastic lamina
  • includes coronary arteries and arteries further away from the heart like brachial and femoral arteries
28
Q

what is the smallest type of artery

A

arterioles

29
Q

describe large arterioles

small?

A

> contain all 3 tunics; resemble small muscular arteries

> endothelium surrounded by 1-2 fiber layers of smooth muscle

30
Q

Describe capillaries (4)

A
  • smallest type of BV > allows erythrocytes to flow in a single line
  • site of gas and nutrient exchange
  • only tunica intima is present
  • permeable
31
Q

what are continuous capillaries (3)

A
  • most common type
  • lining does not contain pores
  • exchange occurs through intercellular clefts and pinocytic vessels
32
Q

what are fenestrated capillaries (2)

A
  • endothelial cells dotted with pores
  • more readily allows passage of fluid and larger molecules
33
Q

what are sinusoid capillaries (2)

A
  • have larger fenestrations and a discontinuous basement membrane
  • allow movement of entire cells through barrier
34
Q

what are venules; describe them

venules converge to form _____, describe their lumen

A

> smallest of vessels carrying blood back to the heart; have all 3 tunics, very thin

> veins, have large lumens

35
Q

what is the percentage of total blood volume in:
- systemic veins
- systemic arteries
- systemic capillaries
- pulmonary circulation
- heart

A
  • 64%

-13%

-7%

-9%

-7%

36
Q

veins contain _____

veins experience much _____ pressure than arteries

A
  • valves
  • lower
37
Q

To ensure blood returns to the heart veins have:2

A
  • larger lumens to offer less resistance to blood flow
  • venous valves (specialized folding of the tunica intima) to ensure unidirectional blood flow
38
Q

what are varicose veins?

causes?

symptoms?

A
  • failure of venous valves, allowing blood to pool in peripheral veins of legs
  • anything that impedes venous return (pregnancy, obesity, prolonged periods of standing)
  • dilation and distension of veins, sometimes causing discomfort or pain
39
Q

what 3 things impact the movement of blood?

A

blood flow, blood pressure, and resistance

40
Q

what is blood flow? (F)

what is blood pressure? (BP/P)

what is resistance? (R)

A

> volume of blood moving through a vessel, tissue, organ, or entire circulation per unit of time

> force exerted onto a given area of the vessel wall by the blood contained within it, measured in mm Hg

> friction encountered by blood, impeding its flow

41
Q

what 3 variable influence resistance?

A

Blood viscosity, blood vessel length, blood vessel radius

42
Q

describe the blood pressure gradient (3)

A
  • change in pressure from one end of the vessel to the other
  • propels blood through vessels
  • pressure is highest in arteries and lowest in veins
43
Q

what is arterial blood pressure

A

when blood flow in the arteries pulses with the cardiac cycle

44
Q

what is systolic pressure (4)

A
  • occurs when ventricle contracts (systole)
  • highest pressure generated in arteries (stretched)
  • recorded as the upper number of the blood pressure ratio
  • EX: systolic pressure is 120 mm H, if blood pressure is 120/80
45
Q

what is diastolic pressure (4)

A
  • occurs when ventricles relax (diastole)
  • lowest pressure generated in the arteries (recoil)
  • recorded as the lower number of blood pressure ratio
  • EX: diastolic pressure is 80 mm Hg if BP is 120/80
46
Q

what is pulse pressure (6)

A
  • pressure in the arteries added by heart contraction
  • equals the difference between systolic and diastolic blood pressure
  • EX: pulse pressure is 40 mm Hg if BP is 120/80
  • reflects elasticity and recoil of arteries (decline with age)
  • allows for palpation of a throbbing pulse in elastic and muscular arteries
47
Q

what is capillary blood pressure (2)

A
  • pressure no longer fluctuates between systolic and diastolic
  • flow and pressure are smooth
48
Q

why is capillary blood pressure important? (5)

A
  • needs to be high enough for the exchange of substances
  • needs to be low enough not to damage vessels
  • arterial end of the capillary at about 40 mm Hg
  • venous end of capillary is below 20 mm Hg
  • accounts for filtration and reabsorption at respective ends

anatomy (17 decks)

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