A&p Ii Final Exam 3 Ch 18

Front 1

2 major blood vessel circuits in the body

Back 1

- Pulmonary circuit: to and from lungs
- Systemic circuit: to and from the rest of the body
- Each circuit begins and ends with the heart

Front 2

Types of vessels

Back 2

- Arteries (transport blood away from heart)
- Veins (transport blood to the heart)
- Capillaries (exchange substances between blood and tissues)

Front 3

List of structures of arteries and veins

Back 3

- Tunica intima
- Tunica media
- Tunica externa

Front 4

Structures of arteries and veins - Tunica intima

Back 4

- Innermost layer
- Endothelial cells and connective tissue with elastic fibers

Front 5

Structures of arteries and veins - Tunica media

Back 5

- middle layer
- contains concentric sheets of smooth muscle (vasoconstriction or vasodilation)
- collagen fibers connect tunica media to other layers

Front 6

Structures of arteries and veins - Tunica externa

Back 6

- outermost layer
- connective tissue sheath with collagen and elastic fibers
- Generally thicker in veins
- Anchor vessel to surrounding tissues

Front 7

Pathway of blood through the heart

Back 7

1) deoxygenated blood is brought in via the superior and inferior vena cava
2) enter right atrium
3) through tricuspid valve
4) enter right ventricle
5) passes through pulmonary semilunar valve
6) through pulmonary trunk
7) to lungs
8) back through pulmonary veins
9) left atrium
10) bicuspid valve
11) left ventricle
12) aortic semilunar valve
13) aorta
14) tissues

Front 8

Name the 3 heart layers

Back 8

- Epicardium
- Myocardium
- Endocardium

Front 9

Epicardium characteristics

Back 9

- Outermost layer, covers the surface of the heart

Front 10

Myocardium characteristics

Back 10

- Forms atria and ventricles
- Contains cardiac muscle tissue, blood vessels and nerves
- Thickest part of the heart (left ventricle has more)

Front 11

Endocardium characteristics

Back 11

- Covering the intermost surface of the heart and valves
- Composed of simple squamous epithelial tissue

Front 12

Compare right and left ventricles

Back 12

- Right: deoxygenated blood, less muscle
- Left: oxygenated blood, more muscle, larger

Front 13

Heart valve locations

Back 13

- Tricuspid valve: right atria
- Bicuspid valve: left atria
- Pulmonary semilunar: pulmonary trunk
- Aortic semilunar valve: aorta

Front 14

Characteristics of cardiac muscle cells

Back 14

- small cell size
- single, centrally located nucleus
- Branching interconnections
- Intercollated discs

Front 15

What is arteriosclerosis and what does it cause?

Back 15

- Thickening or toughening of artery walls
- Causes increased BP
- Coronary vessels = CAD
- Brain arteries = stroke

Front 16

What is atherosclerosis and causes

Back 16

- Most common form of arteriosclerosis
- Often associated with elevated cholesterol
- Formation of lipid deposits in tunica media pushing against tunica intima (damage)

Front 17

Coronary artery disease (CAD)

Back 17

- partial or complete blockage of coronary circulation
- reduced blood flow to area (coronary ischemia) = lower O2
- Usual cause is atheriosclerosis but can also be from blood clot (thrombus)
- Treatment includes a wire mesh tube (stent) to hold vessel open

Front 18

Steps of the cardiac cycle

Back 18

1) All four chambers are relaxed
2) Atrial systole (Contraction)
- atria contract, filling relaxed ventricles with blood
3) atrial diastole
- atria relax
4) ventricular systole #1 (occurs at the same time as #3)
- ventricles contract
- push AV valves closed
- Not enough pressure to open semilunar valves
- "Isovolumetric contraction"
5) Ventricular systole #2
- ventricular pressure increases
- semilunar valves open
- blood leaves ventricles
- "ventricular ejection"
6) Ventricular diastole early
- ventricles relax
- pressure drops
- semilunar valves close
7) Isovolumetric relaxtion
- blood flows into relaxed atria
- AV valves remain closed (all valves closed)
8)Ventricular diastole late
- all chambers relaxed
- ventricles fill passively to 70% volume
- AV valves open

Front 19

Heart sounds

Back 19

- S1: "Lubb", start of ventricular contraction and closure of AV valves
- S2: "dupp", closure of semilunar valves
- S3: blood flowing into ventricles
- S4: atrial contraction
** S3 and S4: very faint, rarely heard in adults

Front 20

What is cardiac output?

Back 20

- amount of blood pumped by left ventricle in one minute

Front 21

What is stroke volume?

Back 21

- amount of blood pumped out of left ventricle during a single heartbeat

Front 22

Cardiac output formula

Back 22

=Heart rate x stroke volume = CO ml/min
- variations affect output: HR can increase, stroke volume can increase

Front 23

What is the conducting system?

Back 23

- A network of specialized cardiac muscle cells responsible for initiating and distributing the stimulus to contract
- Can do on their own (automaticity)

Front 24

Conducting system steps

Back 24

1) Sinoatrial node (SA)
- Posterior wall of right atrium
- Impulse generated is distributed through other components
2) Internodal pathways
- distribute signal to atria on way to ventricles
3) Atrioventricular node (AV)
- junction of atria and ventricles
- also contains pacemaker cells
- of SA node damaged, can maintain lower HR
- signal pauses (atria contract)
4) AV bundle and branches
- interventricular septum
- branches relay signal to ventricles toward heart apex
5) Purkinje fibers
- large diameter conducting cells
- final part of conduction system that triggers ventricular systole

Front 25

Comparison between cardiac and skeletal contraction

Back 25

1) Skeletal:
- action potential is brief
- twitch contraction is short
- twitches can summate and tetanus can occur
2) Cardiac
- action potential is long
- contraction period is long
- tetanic contractions cannot occur
- full contractions and complete relaxation

Front 26

3 stages of cardiac muscle action potential

Back 26

1) Rapid depolarization
- voltage gated fast sodium channels open at threshold
2) Plateau
- transmembrane potential remains near 0mv
- fast sodium channels close
- slow calcium channels open allowing calcium influx
3) Repolarization
- slow calcium channels close
- slow potassium channels open

Front 27

How do autonomic nervous systems affect the heart?

Back 27

- Pacemaker cells in the SA and AV nodes cannot maintain a stable resting potential
- Always gradual depolarization leading to threshold (=prepotential or pacemaker potential)

Front 28

Parasympathetic stimulation on the heart

Back 28

- Ach open K+ channels
- slows heart rate
- slows rate of depolarization
- extends duration in reploarization

Front 29

Sympathetic stimulation on the heart

Back 29

- Ion channels open
- increases rate of depolarization
- shortens duration in repolarization

Front 30

What is bradycardia?

Back 30

- HR slower than normal

Front 31

What is tachycardia?

Back 31

- HR is faster than normal

Front 32

Cardio control centers

Back 32

1) Cardioinhibitory center: controls the parasympathetic neurons to slow heart rate
2) Cardioacceleratory center: controls the sympathetic neurons to increase heart rate

Front 33

End diastolic volume (EDV)

Back 33

- the amount of blood in a ventricle at the end of ventricular diastole
- Right before contraction occurs, end of relaxtion

Front 34

End systolic volume (ESV)

Back 34

- The amount of blood left in the ventricle following contraction

Front 35

Stroke volume formula

Back 35

=EDV - ESV

Front 36

Influences on EDV that would affect stroke volume

Back 36

- Venous return: amount of venous blood returned per minute
- Filling time: duration of ventricular diastole
- Preload: amount of myocardial stretching

Front 37

Influences on ESV that would affect stroke volume

Back 37

- Contractility: amount of force produced during a contraction at a given preload
- Afterload: tension necessary for ventricular ejection

Front 38

Increased venous return = __________EDV

Back 38

increased

Front 39

Decreased venous return = __________EDV

Back 39

decreased

Front 40

Increased HR = __________EDV

Back 40

decreased

Front 41

Decreased HR = __________EDV

Back 41

increased

Front 42

Increased preload = __________EDV

Back 42

increased

Front 43

Decreased preload = __________EDV

Back 43

decreased

Front 44

Increased contractility = __________afterload

Back 44

increased or decreased

Front 45

Increased constriction = __________afterload

Back 45

increased

Front 46

Increased dilation = __________afterload

Back 46

decreased

Front 47

Increased preload = __________contractility

Back 47

increased

Front 48

Decreased preload = __________contractility

Back 48

decreased

Front 49

Increased afterload = __________EDV = __________SV

Back 49

increased; decreased

Front 50

Decreased afterload = __________EDV = __________SV

Back 50

decreased; increased

Front 51

Increased contractility = __________ESV = __________SV

Back 51

decreased; increased

Front 52

Increased filling time = __________EDV

Back 52

increased

Front 53

Decreased filling time = __________EDV

Back 53

decreased

Front 54

What does a ECG do?

Back 54

- records electrical activities of the heart from body surface over time
- used to assess performance of: nodes, conduction system, contractile components

Front 55

Sections of ECG reading

Back 55

- P Wave: atrial depoloarization
- QRS complex: atrial reploarization and ventricular depolarization
- T Wave: ventricular reploarization

Front 56

What is total peripheral resistance?

Back 56

- Resistance of entire cardiovascular system
- Must be overcome by sufficient pressure from the heart (amount of force depends on vascular resistance, viscosity, and turbulence)

Front 57

Vascular resisitance

Back 57

- Largest component of total peripheral resistance
- Primarily results from friction between blood and vessel walls
- Amount of friction depend on vessel length and vessel diameter
*increased length = increased resistance
*decreased diameter (changes throughout the day) = increased resistance

Front 58

Viscosity

Back 58

- Resistance to flow caused by interactions of solutes and suspended materials in a liquid
- Thickness
- Increased viscosity = increased resistance

Front 59

Turbulence

Back 59

- mixed flow with eddies and swirls
- irregular surfaces such as plaque buildup

Front 60

How does blood flow effect blood pressure?

Back 60

Increased blood flow = increased BP

Front 61

Pressure grandient

Back 61

- difference from one end of vessel to other end

Front 62

Where is the highest and lowest average BP

Back 62

- Highest: aorta
- Lowest: vena cava

Front 63

How does atrial pressure vary?

Back 63

- Rising during ventricular systole
- Declining during ventricular diastole

Front 64

What does capillary exchange involve?

Back 64

- Filtration, diffusion and osmosis

Front 65

Diffusion characteristics

Back 65

- Substances flow from higher to lower concentration
- Large solute/proteins usually do not diffuse
- Occurs more rapidly when distances are short, concentration gradient is large, solutes are small
- Proteins usually cannot cross except at sinusoids

Front 66

Where does filtration predominate?

Back 66

arteriole end

Front 67

Capillary hydrostatic pressure (CHP)

Back 67

- highest near arteriole
- causes water and small solutes to enter interstitial fluid
- decreases along capillary length

Front 68

Blood colloid osmotic pressure (BCOP)

Back 68

- increases as filtration occurs
- water leaves capillary and plasma proteins remain

Front 69

When is fluid forced out of the capillary?

Back 69

CHP > BCOP

Front 70

Net filtration pressure (NFP)

Back 70

- The difference between capillary hydrostatic and blood colloid osmotic pressure
- NFP = CHP - BCOP
*Positive = filtration
*Negative = reabsorption

Front 71

Regulatory pathways of blood pressure

Back 71

- Blood flow must match changes in demand for oxygen and nutrients
1) Auto regulation: occurs at local level, no outside influence, in vessels (on their own), vasodilators etc.
2) Central regulation: if autoregulation is ineffective, neural and endocrine control (release of hormones such as ADH etc.)

Front 72

Baroreceptor

Back 72

Monitors BP in vessel to maintain homeostasis

Front 73

Chemoreceptor

Back 73

Measures gas levels (O2, CO2)