A&p The Heart

Front 1

Where is the HEART LOCATED?

Back 1

The heart is located at the MEDIASTINUM (so if you think about it, 'media' --> medial which means middle, and 'stinum' --> 'sternum' which is the one holding your ribs. Therefore, the heart is located in the mediastinum -- the middle of your sternum!)

Front 2

What are PLEURAL MEMBRANES?

Back 2

Pleural Membranes are serous membranes that cover the lungs and act in the same way as the pericardium does for the heart -- in that it provides protection, and lubrication for the lungs.

Front 3

The Mediastinum has how many compartments?

Back 3

The mediastinum contains 3 compartments: the ANTERIOR, the MIDDLE, and the POSTERIOR. The heart is located in the MIDDLE compartment, and the other 2/3 of the heart's mass is slightly to the left of the body's midline!

Front 4

What are the 2 anatomical portions of the Heart?

Back 4

There is the BASE of the heart, which is tipped up medially and posteriorly; and then there's the APEX of the heart, which projects inferiorly and laterally. (Or, in other words, the BASE is the TOP of the heart, and the APEX is the BOTTOM of the heart).

Front 5

What is the FUNCTION of the PERICARDIUM?

Back 5

The Pericardium serves in a few ways:

- Holds the heart in place

- Forms a barrier against infections

- Helps keep the heart from over expanding

- Fluids within the sacs of the pericardium lubricate the outer wall of the heart and allow it to beat without friction.

Front 6

What is the STRUCTURE of the PERICARDIUM like?

Back 6

The pericardium is a tough, fibrous outer layer lined by a delicate serous membrane.

Front 7

What is the FIBROUS PERICARDIUM?

Back 7

The FIBROUS PERICARDIUM is the dense and non-flexible connective tissue that helps to protect and anchor the heart.

Front 8

What is the INNER SEROUS MEMBRANE?

Back 8

The inner serous membrane is subdivided into two layers:

- the Parietal Layer which adheres to the outermost fibrous layer

- the Visceral Layer which also forms the outer surface of the heart's wall. The INNERMOST layer!

Front 9

What is Pericardial Fluid and what is its importance?

Back 9

Pericardial Fluid is the fluid located within the pericardium that acts to reduce friction within the pericardium by lubricating the epicardial surface and allowing the membranes to glide over each other with each heartbeat.

Front 10

What are the 3 Layers of the Heart Wall?

Back 10

There are 3 Layers to the Heart Wall:

- Epicardium

- Myocardium

- Endocardium

Front 11

What is the Epicardium?

Back 11

The Epicardium is the OUTERMOST wall of the heart, composed of connective tissue covered by epithelium. It is also known as the visceral pericardium and serves as an additional layer of protection for the heart

Front 12

What is the Myocardium?

Back 12

The Myocardium is the middle layer of the heart's walls. It is composed of cardiac muscle and serves a few functions:

- provides a scaffolding for the heart's chambers

- assists with the contraction/relaxation of cardiac muscle

- conducts electricity to coordinate contraction/relaxation of cardiac muscle

Front 13

What is the Endocardium?

Back 13

The Endocardium is the innermost layer of the heart's walls, and it lines the chambers of the heart. It provides protection to the valves and the heart chambers and is composed of endothelial cells which help to maintain smooth blood circulation/pumping

Front 14

Cardiac Muscle

Back 14

Cardiac Muscle is STRIATED, with short, branched fibers that contain only one centrally located nucleus. These muscle cells connect to and communicate with neighboring cells via GAP JUNCTIONS in INTERCALATED DISCS!

Front 15

How many chambers does the heart contain?

Back 15

The Heart contains 4 Chambers:

- 2 Upper Chambers known as the RIGHT and LEFT Atria

- 2 Lower Chambers, known as the RIGHT and LEFT Ventricles

**The heart can be thought of as "right and left" pumps or even "top and bottom" pumps.

Front 16

What is the FUNCTION of the TOP part of the Heart?

Back 16

The TOP part of the heart consists of the Right and Left Atria. These are rather WEAK pumps which serve to load the ventricles via an 'atrial kick' before ventricular contraction occurs.

Front 17

What is the FUNCTION of the BOTTOM part of the Heart?

Back 17

The Bottom part of the heart consists of the Right and Left Ventricles, which are rather STRONG pumps, and serve as the main pump for pulmonary and systemic circulation!

**Specifically the LEFT ventricle is the strongest of all 4 chambers!

Front 18

What is the 'Atrial Kick'?

Back 18

The Atrial Kick is the last contraction the atrium makes as it sends blood into the ventricles. As this last contraction takes place, the ventricles take over and draws in the blood. It is responsible for about a 20% increase in the amount of blood ejected by the ventricles (and eventually amounts to a flutter as we age)

Front 19

What is Atrial Fibrillation?

Back 19

Atrial Fibrillation is when there is no atrial kick present in the processes of the atrium, and can attribute to shortness of breath, heart palpitations and weakness.

Front 20

Which way does blood flow? And why is blood flow important to heart functioning?

Back 20

Blood flows from an area of HIGH to LOW pressure! It is dictated strictly by differences in pressure (nothing to do with muscles).

The flow of blood operates the valves of the heart!

Front 21

How do our heart valves operate?

Back 21

Valves operate in TWO pairs:

- Atrioventricular Valves (AV) allow blood flow from the atria into the ventricles.

- Outflow (Semilunar Valves [SL]) allow blood flow from the ventricles into the outflow vessels.

Front 22

What are the parts of the AV valves?

Back 22

The AV valves are positioned at the entrance of each ventricle, thus meaning there are two of them.

- Right AV Valve is AKA the Tricuspid Valve and it opens into the right ventricle

- Left AV Valve is AKA the Bicuspid/Mitral Valve and it opens into the left ventricle

Front 23

What is the Chordae Tendineae?

Back 23

The chordae tendineae are strong, fibrous strings attached to the cusps of the heart on the ventricular side (lower part).They originate from the papillary muscles and serve as the attachment for the AV valves to the walls of the ventricles.

Front 24

What happens when the Papillary Muscles contract?

Back 24

The AV valve closure slows to prevent trauma

Front 25

What are the OUTFLOW VALVES?

Back 25

These are positioned at the entrance to outflow vessels leading into the pulmonary and systemic circulation. They are the [top] part of the heart, and consist of two parts:

- Right Outflow Valve (Pulmonary Valve) opens into the pulmonary trunk

- Left Outflow Valve (Aortic Valve) opens into the aortic arch

Front 26

How do Outflow Valves work?

Back 26

Well, outflow valves open with the act of ventricular ejection and close when blood in the aorta and pulmonary outflow tract begins to leak back into ventricles.

Front 27

Back 27

Front 28

What are the two circuits of blood flow?

Back 28

There are TWO circuits of blood flow:

- Systemic Circuit

- Pulmonary Circuit

Front 29

What does the Systemic Circuit do? How does it work?

Back 29

The Systemic Circuit ejects blood into the aorta, systemic arteries, and arterioles. It is powered by the LEFT side of the heart.

Front 30

What does the Pulmonary Circuit do? How does it work?

Back 30

The Pulmonary Circuit ejects blood into the pulmonary trunk. It is powered by the RIGHT side of the heart.

Front 31

What is the PULMONARY TRUNK?

Back 31

The pulmonary trunk is a major vessel of the human heart that originates from the RIGHT ventricle. It branches into the R&L pulmonary arteries, which lead straight to the lungs.

Front 32

What are the 3 Steps in Blood Flow?

Back 32

1.) Venous return to the heart; deoxygenated blood flows into the R atrium from the two vena cava and the coronary sinus

2.) Blood flows through the R heart to the lungs to be oxygenated

3.) Oxygenated blood returns to the L heart to be pumped through the outflow tract of the systemic circulation

Front 33

What are the 3 Major Arteries attaching to the heart?

Back 33

- Arch of the Aorta

- Pulmonary Trunk

- Coronary Arteries

Front 34

What is the Superior Vena Cava?

Back 34

The Superior Vena Cava carries deoxygenated blood into the heart from the head, neck and upper limbs. It also dumps blood into the R atrium.

Front 35

What is the Inferior Vena Cava?

Back 35

The Inferior Vena Cava carries deoxygenated blood into the heart from the lower body. It also dumps blood into the R atrium.

Front 36

What is the Coronary Sinus?

Back 36

The Coronary Sinus is where the blood is returned to the R atrium. It receives its blood via the Coronary Arteries (which branches from the aorta).

Front 37

What is the Aorta?

Back 37

The Aorta is the main artery of the body. It supplies large amounts of oxygenated blood to the rest of the body with a high pressure. It passes over the L ventricle and runs down in front of the backbone.

Front 38

What are the major VEINS attaching to the heart?

Back 38

There are THREE major veins that attach to the heart:

- Superior and Inferior Vena Cava

- the 4 Pulmonary Veins

- The Coronary Sinus (which is located on the back of the heart).

Front 39

What do the 4 Pulmonary Veins do?

Back 39

They carry oxygenated blood into the L atrium

Front 40

Back 40

Front 41

WHat is the direction of blood flow?

Back 41

Front 42

Where are the Coronary Vessels located on the heart?

Back 42

** Only the innermost tissues lining the chambers of the heart can derive oxygen from the blood flowing through those chambers

Front 43

What is the difference in functioning of the coronary veins and the coronary sinus?

Back 43

The coronary veins all collect into the coronary sinus at the posterior of the heart. Meanwhile, the coronary sinus empties into the RIGHT atrium. Deoxygenated coronary blood joins oxygen-depleted blood from the rest of the body.

Front 44

Where are the coronary veins located on the heart?

Back 44

the coronary veins drain blood from the heart wall and empty into the coronary sinus.

Front 45

What is Autorhythmicity?

Back 45

Autorhythmicity is the rhythmical electrical activity produced individually by special myocytes within the heart.

Front 46

What is the Cardiac Conduction System?

Back 46

The Cardiac Conduction System is a specialized group of myocytes that have the unusual ability to spontaneously depolarize.

Front 47

What are the MAIN components of the Cardiac Conduction System?

Back 47

There are 5 MAIN components of the Cardiac Conduction System:

* SA Node

* AV Node

* Bundle of His

* Bundle branches

* Purkinje fibers

Front 48

What are the 2 important roles of the self-excitable myoctyes that "act like nerves"?

Back 48

The self-excitable myocytes that "act like nerves" have two important roles:

~ Conduction System of the heart

~ Pacemaker

Front 49

What is the Sinoatrial (SA) Node?

Back 49

The SA node is located in the RIGHT ATRIAL WALL, below the entry of the superior vena cava. It has TWO main features:

~ To act as the Pacemaker of the heart

~ It has the fastest rate of depolarization

Front 50

How often do the autorhythmic fibers in the SA node spontaneously depolarize?

Back 50

They fire about once every 0.6 seconds, or 100 action potentials per minute. This act [of spontaneous depolarization] is modified by the ANS

Front 51

What are the steps of the Cardiac Conduction System?

Back 51

Front 52

What is functional syncytium?

Back 52

This is the way that bands of muscles wind around the heart and work together as a unit. This allows the top ad bottom parts to contract in their own unique way.

Front 53

Why does the atrial muscle synctyium contract as a single unit?

Back 53

The atrial muscle syncytium contracts as a single unit to force blood down into the ventricles!

Front 54

Where does the syncytium of the ventricular muscle begin contraction at? Why does it start there?

Back 54

The syncytium of the ventricular muscle starts contracting at the APEX of the heart, in order to squeeze blood upwards to exit out the outflow tracts

Front 55

What is an Action Potential (AP)?

Back 55

The change in electrical potential associated with the passage of an impulse along the membrane of a muscle or nerve cell.

Front 56

What is the job of the AP within the cardiac muscle?

Back 56

The AP of a cardiac muscle is initiated by SA node and travels through the conduction system in order to excite 'working' contractile muscle fibers within the atria and ventricles.

Front 57

What are contractile fibers?

Back 57

Contractile fibers are fibers that are made up mostly of proteins that contract when stimulated and relaxes when not stimulated.

Front 58

What does RMP stand for?

Back 58

Resting Membrane Potential

Front 59

What is the stable RMP of contractile fibers?

Back 59

The stable RMP of contractile fibers is -90mV (unlike autorhythmic fibers)

Front 60

How do AP spread widely throughout the heart?

Back 60

AP is able to spread widely throughout the heart by opening and closing the Na+ [sodium] and K+ [potassium] channels

Front 61

Analyze this diagram:

Back 61

Front 62

What is the Refractory Period?

Back 62

The refractory period lasts longer than the contraction itself. In fact, another contraction cannot begin until relaxation is underway! (this is where cardiac muscle differs from skeletal muscle)

Front 63

What is Tetanus?

Back 63

Tetanus is maintained contraction caused by rapidly repeating stimuli.

Front 64

Why can't Tetanus happen in cardiac muscle?

Back 64

Because it is maintained, constant contraction it therefore cannot occur in cardiac muscle, because cardiac muscle MUST have a refractory period in order to leave a sufficient amount of time between contractions for the chambers of the heart to fill with blood!

Front 65

What are the mechanisms of contraction in cardiac muscle?

Back 65

* Electrical activity leads to Ca2+ release from the SR

* Actin & Myosin filaments go through the contraction cycle

* Tension develops as filaments slide past one another

Front 66

What are the steps of an EKG?

Back 66

Front 67

What is an ECG/EKG?

Back 67

An EKG/ECG is a recording of electrical changes on the surface of the body resulting from depolarization and repolarization of the myocardium.

Front 68

What do EKGs measure?

Back 68

EKGs measure the presence or absence of certain waveforms (deflections), the size of the waves, and the time of the intervals of the cardiac cycles.

*EKGs allows us to quantify and correlate, electrically, the mechanical activities of the heart.

Front 69

What are the 5 Major Waves within an EKG?

Back 69

*P-wave

*P-Q Interval

*QRS Wave

*T-wave

*S-T Segment

Front 70

What does the P Wave measure?

Back 70

The P-wave measures the atrial depolarization

Front 71

What does the P-Q Interval measure?

Back 71

The P-Q Interval measures the time it takes for the atrial kick to fill the ventricles

Front 72

What does the QRS Wave measure?

Back 72

The QRS Wave measures the ventricular depolarization and atrial repolarization.

Front 73

What does the S-T Segment measure?

Back 73

The S-T segment measures the time it takes to empty the ventricles before they repolarize

Front 74

What does the T-Wave measure?

Back 74

The T-wave measures ventricular repolarization (which occurs as the ventricles relax).

Front 75

KNOW THIS DIAGRAM

Back 75

Front 76

What is the Pressure-Volume Loop?

Back 76

The pressure-volume loop is when the cycle that occurs within the heart when ALL FOUR valves are closed at the same time for a quick second. This then promotes a large level of pressure within the heart, which is what helps the heart to eject its blood. Afterwards, the four valves all close once again very quickly while it refills with blood to start the ejection cycle again.

Front 77

What is Hemodynamics?

Back 77

Hemodynamics relates the forces and motion of blood flow and the science concerned with the study of the circulation of blood. It determined oxygen and nutrient delivery, as well as metabolic end product removal.

Front 78

What is Cardiac Output?

Back 78

Cardiac Output is the amount of blood ejected by the heart per minute! (it is around 5 L per minute!)

Front 79

What is the formula that goes along with cardiac output?

Back 79

Q = SV x HR

where Q --> cardiac output

SV --> stroke volume

HB --> heart beat

Front 80

What is the typical Q in adult males?

Back 80

The typical Q in adult males is around 5.25L/min

(in formula, it would look like SV = 75mL/beat x 75 bpm)

Front 81

What are the THREE important factors affecting the Stroke Volume?

Back 81

* Preload

* Myocardial Contractility

* Afterload

Front 82

What is Preload?

Back 82

Preload is the degree of myocardial fiber stretching at the end of diastole and before contraction.

Front 83

What is diastole?

Back 83

Diastole is the phase of the heartbeat when the heart muscles relax and allows the chambers to fill with blood.

Front 84

What is Starlings Law of the Heart?

Back 84

With a greater preload on cardiac muscle just before they stretch comes an increase in their force of contraction during stystole

Front 85

Define systole

Back 85

Systole is the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries.

Front 86

What is Afterload?

Back 86

Afterload is the resistance of flow, which affects how hard the heart must pump in order to push blood out (the pressure of the ventricle must overcome to eject its own volume).

Front 87

What is the peripheral component of the afterload?

Back 87

The pressure the heart must overcome to open the aortic valve. This process depends on TWO things:

*Aortic compliance

*Total systemic vascular resistance (or the blood viscosity and arteriolar constriction).

Front 88

What is Myocardial Contractility?

Back 88

Myocardial contractility is the force and velocity with which ventricular ejection occurs INDEPENDANT of the effects of preload/afterload.

Front 89

What is an example of myocardial contractility?

Back 89

When catecholamines are released they can increase contractility (in moments of fear, stress, pain).

Front 90

What is myocardial compliance?

Back 90

Myocardial compliance is the ventricle's ability to stretch and receive a given volume of blood. Normally, ventricles are very compliant, so large changes in their volumes produce only small changes in pressure.

Front 91

What is LOW COMPLIANCE? (in regards to myocardial compliance)

Back 91

LOW COMPLIANCE is when small changes in volume result in large changes in pressure within the ventricle. This occurs when the ventricle cannot stretch, which thus limits its ability to increase cardiac output with an increased preload.

Front 92

What is Ejection Fraction?

Back 92

Ejection Fraction (EF) is the percentage of blood that is pumped out of the ventricles with each heartbeat.

Front 93

What does the EF formula look like?

Back 93

EF = SV / EDV

where EF --> Ejection Fraction

SV --> stroke volume

EDV --> end diastolic volume

Front 94

What happens in decreased systolic function?

Back 94

A decrease in contractility, and valvular diseases

Front 95

What happens in increased systolic function?

Back 95

Hypertrofic cardiomyopathy

Front 96

What are the normal values of Ejection Fraction (EF)?

Back 96

Greater than or equal to 50-55% EF is known as an increased EF and other inotropic actions

Less than 40% indicates systolic dysfunction.

Front 97

Why is the Frank-Starling Law of the Heart important?

Back 97

It equalizes the output of R & L ventricles; keeps same volume of blood flowing to both systemic and pulmonary circuits).

Front 98

What are two agents that affect Myocardial contractility?

Back 98

1) Positive inotropic agents INCREASE contractility as well as stroke volume

2) Negative inotropic agents DECREASE contractility as well as stroke volume.

Front 99

What is cardiac reserve?

Back 99

Cardiac Reserve is the difference between Q at rest and the max Q.

Front 100

What is the average Cardiac Reserve?

Back 100

The average cardiac reserve is about 4-5x resting values

**exercise draws upon cardiac reserve to meet the body's increased physiological demands and maintain homeostasis.

Front 101

Back 101

Front 102

Why do we measure blood pressure instead of blood flow?

Back 102

Blood flow is hard to measure, but blood pressure is easier and it is related to blood flow so we measure that instead!

Front 103

What is Ohms Law?

Back 103

Ohms Law is the equation that draws out the relationship between blood flow, blood pressure, and peripheral resistance. It looks like this:

BP = Flow x Resistance

Front 104

What is Blood Flow?

Back 104

Blood flow is the amount of blood that actually reaches the end organs

Front 105

What is Blood Pressure?

Back 105

Blood Pressure (BP) is a measure of the force (in mmHg) exerted in the lumen (cavity) of blood vessels.

Front 106

What is Resistance?

Back 106

Resistance is the sum of many factors which oppose the flow of blood!

Front 107

What sort of factors aid in the resistance of blood?

Back 107

Front 108

What are the TWO types of venous return?

Back 108

~~ Skeletal Muscle Pump

~~ Respiratory Pump

Front 109

What does the Skeletal Muscle Pump do?

Back 109

The Skeletal Muscle Pump uses the action of muscles to milk blood in one direction (dude to the valves).

Front 110

What does the Respiratory Pump do?

Back 110

The Respiratory Pump uses the negative pressures in the thoracic and abdominal cavities generated during inspiration to pull venous blood towards the heart

Front 111

What are the names of the two valves utilized in the skeletal muscle pump?

Back 111

The proximal valve and the distal valve

Front 112

What are the factors affecting BP?

Back 112

Front 113

What are Baroreceptors?

Back 113

Baroreceptors are pressure-sensitive sensory receptors located in the aorta, internal cortid arteries, and other lage arteries located in the neck/chest.

Front 114

What type of changes occur in HR during parasympathetic and sympathetic reactions?

Back 114

Para --> DECREASE HR

Symp --> INCREASED HR

Front 115

What are chemoreceptors?

Back 115

Chemoreceptors are sensory receptors that monitor chemical composition of blood. They are located in the carotid and aortic bodies and detect changes in O2, CO2, and H+ with their input being sent to the cardiovascular and cardiorespiratory centers.

Front 116

BP: Hormonal Regulation

Back 116

Front 117

How can one measure peripheral circulation?

Back 117

By checking the PULSE!

Front 118

What is a pulse?

Back 118

The pulse is a result of the alternate expansion and recoil of elastic arteries after each systole. They are strongest in arteries closest to the heart, and get weaker the further they get away.

Front 119

What is the relationship between pulse and HR?

Back 119

Normally, the pulse is the same as the heart rate

Front 120

Tachycardia

Back 120

...

Front 121

Bradycardia

Back 121

...

Front 122

What do Arteries do?

Back 122

Arteries carry blood AWAY from the heart. They are normally oxygenated blood, but carry deoxygenated blood in the pulmonary circuit

Front 123

What are the three types of arteries?

Back 123

--Large elastic arteries (>1cm)

--Medium muscular arteries (0.1 - 10mm)

--Arterioles (<0.1 mm)

Front 124

What are capillaries?

Back 124

Capillaries are the site of nutrient and gas exchange!

Front 125

What are do veins do?

Back 125

Vein carry blood TOWARDS the heart. Usually oxygenated only in the pulmonary circuit and deoxygenated in the systemic circuit

Front 126

What are venules?

Back 126

Small veins (<0.1 mm)

Front 127

What are the 3 basic layers of blood vessels?

Back 127

*Tunica Intima

**Tunica Media

***Tunica Externa (adventitia)

Front 128

What is the Tunica Intima?

Back 128

The Tunica Intima is the endothelium lining the cavity (lumen) of all vessels

Front 129

What is Tunica Media?

Back 129

Tunica Media is the muscular and connective layer that is responsible for vasodilation and vasoconstriction

Front 130

What is the Tunica Externa?

Back 130

The Tunica Externa anchors the vessels to their surrounding tissues. They contain elastic and collagen fibers, nerve endings, and small blood vessels.

Front 131

What is VASA VASORUM?

Back 131

The vasa vasorum is a network of small blood vessels that supply the walls of large blood vessels such as elastic arteries and large veins. They are related to the tunica externa

Front 132

Label the passage of blood through the arteries in order from first to last place visited.

Back 132

Elastic arteries --> Muscular arteries --> Arterioles

Front 133

What exactly are Elastic (conducting) Arteries?

Back 133

Elastic arteries are the largest arteries, about the size of a garden hose. Their walls are thin compared to their overall size, and they serve to store mechanical energy during ventricular systole as a sort of pressure reservoir. They also are in charge of transmitting that energy to keep blood moving after aortic and pulmonary valves close.

Front 134

What are Muscular (disturbing) Arteries?

Back 134

These are the medium sized arteries, found in two places of the body: brachial artery in the arm and the radial artery in the forearm. They have even more reserves of smooth muscle in their tunica media. Their main function is to help maintain proper vascular tone to ensure efficient blood flow to distal tissue beds.

Front 135

What are Anastomoses?

Back 135

Anastomoses is a union of vessels supplying blood to the same body tissue.

Front 136

Why are anastomoses beneficial?

Back 136

They provide collateral circulation (an alternative route) for blood to reach a tissue in instances of occlusion /blockage.

Front 137

What are Arterioles?

Back 137

These are abundant microscopic vessels with a thin tunica interna and tunica media. They act to regulate blood flow into capillaries and influence the greatest collective influence on both the local blood flow and on overall blood pressure.

Front 138

What are Metarteriole?

Back 138

Metarterioles are the termical ends of an arteriole that tapers towards the capillary junction

Front 139

What is a Precapillary Sphincter?

Back 139

A precapillary sphincter is formed by most distal muscle at the metarteriole capillary junction. It monitors and regulates blood flow into the capillary bed.

Front 140

What is the structure of capillaries like?

Back 140

Capillaries have a single layer of endothelial cells and a thin basemement membrane. Meaning they lack tunica media and tunica externa. The way they are formed allows them to be freely permeable to many susbtances.

Front 141

What is the function of capillaries?

Back 141

to exchange gases, fluids, and small ionic molecules

Front 142

In relation to pressure, how do veins operate compared to arteries?

Back 142

Because veins have thinner walls, less muscle and elastic tissue they operate at LOWER PRESSURES than arteries.

Front 143

What are the intravenous pressures?

Back 143

Venules have a pressure of 16mmHg

Large Veins have a pressure of 1-2 mmHg

Arterioles have a pressure of 35 mmHg

Front 144

Why are valves required?

Back 144

Because veins have lower pressures, so there is a low intravenous pressure in the body circulation system.

Front 145

What are varicose veins?

Back 145

Varicose veins are when veins are exposed to higher than normal pressure, and they become incompetent because of it.

Front 146

How many divisions does the respiratory system consist of?

Back 146

The respiratory system is divided into 2 zones: the

-- Conducting Zone

-- Respiratory Zone

Front 147

What are the duties of the CONDUCTING ZONE?

Back 147

The conducting zone is in charge of filtering, warming, and moistening the air as well as delivering it to the site of respiration in the lungs.

Front 148

What does the conducting zone consist of?

Back 148

The conducting zone consists of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.

Front 149

What are the duties of the RESPIRATORY ZONE?

Back 149

The respiratory zone is the MAIN SITE OF GAS EXCHANGE between air and blood.

Front 150

What does the respiratory zone consist of?

Back 150

The respiratory zone consists of the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli

Front 151

What are the functions of the respiratory system?

Back 151

~ Provides gas exchange (intake O2, removal of CO2)

~ Helps regulate pH

~ Contain receptors for smell, filters inspired air, produces vocal sounds, and excretes small amounts of water and heat.

Front 152

What is the order of air passage through the Upper respiratory tract?

Back 152

Nose --> nasal cavity --> pharynx

Front 153

What is the order of air passage through the Lower respiratory tract?

Back 153

Larynx --> Trachea --> Primary (1) bronchi --> Secondary (2) bronchi --> Tertiary (3) bronchi --> Bronchioles --> Alveoli

Front 154

What is the NASAL CAVITY?

Back 154

The nasal cavity is inferior to the nasal bone and superior to the oral cavity, divided by the nasal septum into the right and left nares. It is important in:

~ ducts from paranasal sinus (mucus) and nasolacrimal ducts drain into the nasal cavity

~ Olfactory receptors

~ contains nasal conchae (which protrude from each lateral wall).

Front 155

What does the nasal cavity do?

Back 155

The nasal cavity warms, moistens, and filters incoming air. It also detects olfactory stimuli.

Front 156

What is the PHARYNX?

Back 156

The passageway to the pharynx begins posteriorly to internal nares and descends to opening of larynx in the neck.

Front 157

What are the three anatomical regions of the pharynx?

Back 157

~ Nasopharynx

~ Oropharynx

~ Laryngopharynx

Front 158

What are the duties of the pharynx?

Back 158

the functions of the pharynx are to:

~serve as a passageway for air/food

~resonating chamber

~housing for tonsils

Front 159

What is the Nasopharynx and what does it do?

Back 159

The Nasopharynx is the first (top) location of the pharynx. It contains the opening of the Eustachian Tubes (auditory). It also contain the pharyngeal tonsils (adenoids) and internal nares.

Front 160

What is he Oropharynx and what does it do?

Back 160

The oropharynx is the middle region of the pharynx. It serves both the respiratory and digestive functions. It's where the opening of the mouth is located as well as the main palatine tonsils & small lingual tonsil.

Front 161

What is the Laryngopharynx and what does it do?

Back 161

It is the bottom region of the pharynx. It also serves both respiratory and digestive functions. It open into the larynx and the esophagus.

Front 162

What is the larynx?

Back 162

The larynx connects the laryngopharynx with the trachea. It's composed of 9 pieces of cartilage that altogether form a short passageway.

Front 163

What is the Thyroid Cartilage?

Back 163

The "Adam's Apple" found in the larynx

Front 164

What is the importance of knowing where the cricoid cartilage is?

Back 164

The cricoid cartilage is found in the larynx and it's the serves as the landmark for performing a cricothyrotomy (putting straw through neck to allow person to breathe).

Front 165

What is the trachea? What is its function?

Back 165

The trachea is anterior to the esophagus and is around 12 cm in length. It's a semi-rigid pipe of semi-circular incomplete circular incomplete cartilaginous rings.

Front 166

What are special about the branches from the trachea?

Back 166

All branches from the trachea to the terminal branchioles are part of the CONDUCTING AIRWAYS and DO NOT participate in gas exchange!!

Front 167

What are the PRIMARY BRONCHI?

Back 167

The primary bronchi emerge from the inferior trachea and split into RIGHT and LEFT main bronchus. They then also divide into SECONDARY (lobar) BRONCHI, which each supply one lobe: 3 on the right and 2 on the left. From there, the lobar bronchi breaks into TERTIARY (segmental) bronchi which also continues dividing down another 23 times. They then continue on into the bronchioles (tubes smaller than 1 mm) and then onto the terminal bronchioles.

Front 168

What is the CARINA?

Back 168

The carina is an internal ridge located at the junction of the two main stem bronchi - which is a very sensitive area for triggering the cough reflex.

Front 169

What is the RESPIRATORY ZONE?

Back 169

This is the end-point of the respiratory tree where the terminal bronchioles divide in respiratory bronchioles that lead into alveolar ducts that then open unto alveolar sacs that contain alveoli

Front 170

What are alveoli?

Back 170

Air exchange chambers

Front 171

What provides a large area for gas exchange?

Back 171

millions of alveoli provide a large area for gas exchange (close to around 1000 sq ft).

Front 172

Describe alveoli.

Back 172

Alveoli are surrounded by fine elastic fibres and are interconnected with the alveolar pores.

Front 173

What are alveolar macrophages?

Back 173

free floating 'dust cells'

Front 174

What type(s) of cells are present in alveoli?

Back 174

Type I and Type II cells are present in alveoli.

Type I cells are epithelial cells and granular pneumocytes.

Type II cells are also epithelial cells that secrete surfactant.

Front 175

What is surfactant?

Back 175

Surfactant is a detergent-like substance secreted in fluid coating alveolar surfaces (alveolar fluid) that acts to decrease tension. It is secreted by TYPE II cuboidal epithelial cells (which are scattered within the alveolar walls).

Front 176

What happens without surfactant?

Back 176

Without surfactant alveolar walls would stick together during exhalation.

Front 177

Describe the anatomy/structure of the R lung

Back 177

The R lung is divided by the oblique and horizontal fissures into 3 lobes:

1) Superior Lobe

2) Middle Lobe

3) Inferior Lobe

Front 178

Describe the anatomy/structure of the L lung

Back 178

The L left is divided by the oblique fissure into 2 lobes:

1) Superior Lobe

2) Inferior Lobe

Front 179

Where is the BASE of the lung?

Back 179

Actually located at the base - the bottom

Front 180

Where is the APEX of the lung located?

Back 180

The apex is located at the top of the lung

Front 181

What is the cardiac notch?

Back 181

it is located in the L lung and makes the left lung 10% smaller than the right lung. It is the indentation for the heart.

Front 182

What is the structure of the thoracic cavity?

Back 182

Front 183

What is the PLEURA?

Back 183

A double-layered serous membrane that encapsulates the lungs. Split into 2 layers:

~ Parietal pleura

~ Visceral pleura

Front 184

What is the parietal pleura?

Back 184

The parietal pleura lines the walls of the thoracic cavity

Front 185

What is the visceral pleura?

Back 185

The visceral pleura adheres tightly to the surface of the lungs themselves.

Front 186

What is the intrapleural space?

Back 186

The intrapleural space is a slit-like space filled with pleural fluid. This is crucial to the mechanism of breathing.

Front 187

What is pleural fluid?

Back 187

Pleural fluid prevents friction of lungs against the rib cage and maintains lung expansion.

Front 188

What is pulmonary ventilation?

Back 188

The movement of air between the atmosphere and the alveoli

Front 189

What is Boyle's Law?

Back 189

The pressure of a gas in a closed container is said to be inversely proportional to the volume of the container.

Front 190

Why does pulmonary ventilation occur?

Back 190

Pulmonary ventilation occurs due to implications of Boyle's Law. By changing the VOLUME of the thoracic cavity and lungs, the PRESSURE in the lungs will also change.

Front 191

What 2 things does pulmonary ventilation consist of?

Back 191

Inhalation and Exhalation

Front 192

What are the muscles of inhalation/exhalation?

Back 192

Front 193

What happens during the contraction of the diaphragm?

Back 193

The diaphragm and the external intercostal (rib) muscles increase the size of the thorax and decreases intrapleural pressure, which results in inhalation.

Front 194

What happens during the relaxation of the diaphragm?

Back 194

With or without the contraction of the interal intercostalis, the size of the thorax decreases and the air pressure increases, resulting in exhalation.

Front 195

What is the difference between quiet (normal) and forced (labored) respiration?

Back 195

During normal quiet inhalation the diaphragm and the ext. intercostalis contract. However, during forced, labored inhalation the sternocleidomastoid, scalenes, and pectoralis minor also contract.

Front 196

What are the characteristics of inspiration?

Back 196

during inspiration:

~Chest walls expand due to muscle contraction

~Pressure in alveoli decreases

~Air moves towards the alveoli

Front 197

What are the characteristics of exhalation?

Back 197

during exhalation:

~Passive process, so the muscles relax.

~Chest wall returns to resting state

~Alveoli become compressed

~Alveolar pressure increases

~Air moves outwards.

Front 198

What is Tidal Volume?

Back 198

Tidal volume is the volume of air inhaled or exhaled with each breath during quiet breathing,

Front 199

What is respiratory frequency?

Back 199

the number of breaths per minute

Front 200

What is minute ventilation?

Back 200

the total volume of inhaled/exhaled air oer minute

Front 201

How many breaths per minute does a healthy adult take at rest?

Back 201

12 breaths per minute

Front 202

Approximately how much air is moved in/out of the lungs per breath?

Back 202

~500mL of air is moved in/out of the lungs per breath.

Front 203

What is inspiratory reserve volume?

Back 203

the max volume f inhaled air beyond the end-inhaled level

Front 204

What is expiratory reserve volume?

Back 204

the max volume of exhaled air beyond the end-expiratory level.

Front 205

What is the residual volume of males/females?

Back 205

Males = 1200mL and females = 1100mL

Front 206

What factors effect the airflow?

Back 206

~Pressure

~Surface Tension

~Compliance

~Airway Resistance

Front 207

What is surface tensions?

Back 207

Surfactant decreases surface tension and prevents the complete collapse of alveoli

Front 208

What is compliance?

Back 208

The indicator of expandability. It is the change in volume when subjected to an applied force. There are 3 factors that affect compliance:

~Connective tissue structure of the lungs

~Level of surfactant production

~Mobility of the thoracic cage

Front 209

What is airway resistance?

Back 209

Airway resistance is when bronchodilation causes a drop in resistance. Airway diamter is regulated by smooth muscle tone, which is dependent on the sympathetic and parasympathetic tone.

Front 210

Define/describe central chemoreceptors

Back 210

Central chemoreceptors are located on the medullary rhythmicity area. It is sensitive to carbon dioxide and pH in the CSF.

Front 211

Define/describe the dorsal respiratory group

Back 211

the dorsal respiratory group is always functioning during normal breathing. It is sensitive to blood, CO2 and pH levels. Its also located on medulla

Front 212

Define/describe the ventral respiratory group

Back 212

It is always functioning during forceful breathing. Also located on the medulla (controls the accessory muscles).

Front 213

Define/describe the peripheral chemoreceptors

Back 213

Peripheral chemoreceptors detect variations of CO2, O2, and the pH of blood

Front 214

Define/describe pneumotaxic center

Back 214

the pneumotaxic center recieves inputs from higher brain centers and peripheral receptors and fine tunes the breathing rhytm during speaking/sleeping/exercising.

Front 215

Define/describe apneustic center

Back 215

apneustic centers sends inhibitory signals to the medulla, reducing duration of inhalation impulse and thus causing shorter cycles which increases the ventilation rate.

Front 216

What other brain areas are involved in the control of respiration?

Back 216

-cortex has voluntary control of breathing

-stretch receptor sense over-inflation and arrests breathing temporarily (herring-breuer reflex)

-emotions w/in limbic system affect breathing

-the hypothalamus senses fever/moderate pain and increases breathing

Front 217

What stimulates central chemoreceptors?

Back 217

An increase in the pressure of CO2 (via a decrease in pH levels)

Front 218

what stimulates the peripheral chemoreceptors?

Back 218

it follows the aortic arch and carotid bodies and it's stimulated by an increase in the pressure of CO2 (via a decrease in pH levels), a decrease in the pressure of O2 and a decrease in the pH levels.

Front 219

Define respiration

Back 219

the exchange of gas

Front 220

What is Dalton's Law?

Back 220

Dalton's Law is the total pressure of a mixture f gases is equal to the sum of the partial pressures of the individual gases in the mixture

Front 221

What is partial pressure

Back 221

the hypothetical pressure of a gas if it alone occupies the volume of the mixture at the same temperature.

Front 222

What is total pressure?

Back 222

the sum of the partial pressure of all gasses in a mixture

Front 223

What 4 gasses compose the atmosphere?

Back 223

-nitrogen (N2)

-oxygen (O2)

-carbon dioxide (CO2)

-water vapor

Front 224

What does the respiratory system depend on?

Back 224

the medium of the earth's atmosphere to extract the oxygen necessary for life

Front 225

WHat What are the 5 effficiencies of gas exchange?

Back 225

1) Substantial differences in partial pressure across the respiratory membrane

2) short distance for gas exchange

3) O2 and CO2 are lipid soluble

4) total surface area if large

5) coordinated blood flow and airflow

Front 226

What is respiration?

Back 226

The exchange of gases

Front 227

What is external respiration (pulmonary)?

Back 227

The gas exchange between alveoli and blood

Front 228

What is internal respiration (tissue)?

Back 228

gas exchange between the systemic capillaries and the tissues of the body

Front 229

What is cellular respiration?

Back 229

ATP production in the tissue cells

Front 230

How many molecules of O2 can each molecule of hemoglobin (Hb) carry?

Back 230

Each Hb molecule can carry 1,2,3, or 4 molecules of O2.

Front 231

What is the most important factor when determining how much O2 binds to Hb?

Back 231

PO2 is the most important factor that determines how much O2 binds to Hb

Front 232

What does the Oxyhemoglobin Dissociation Curve show?

Back 232

It illustrates the relationship between the % of saturation of Hb and PO2.

Front 233

What does oxyhemoglobin mean?

Back 233

hemoglobin that's fully saturated

Front 234

What is SaO2

Back 234

The amount of Hb saturated with O2

Front 235

oxyhemoglobin has a % level of _____SaO2?

Back 235

95-98%

Front 236

When blood returns, it still has 3/4 O2 binding sites, making the % level of SaO2 at _____?

Back 236

75%

Front 237

What is the average PO2 of tissue at rest?

Back 237

40 mmHg (that's when Hb is 75% saturated)

Front 238

What is the PO2 when Hb is 90% saturated with O2?

Back 238

The PO2 60-100 mmHg

Front 239

When PO2 is at 40-20 mmHg, what is the Hb?

Back 239

Hb becomes 35% saturated with O2

Front 240

Back 240

Front 241

What is the BOHR EFFECT?

Back 241

increasing blood acidity towards tissue (pH decreases), shifts the O2-Hb saturation curve "to the right", thus enhancing the unloading of O2

Front 242

What is the HALDANE EFFECT?

Back 242

The removal of O2 from Hb increases Hb affinity for CO2 and thus allows CO2 to "ride" on the empty Hb.

Front 243

What is Henry's Law?

Back 243

the quantity of a gas that will dissolve in a liquid is proportional to the partial pressures of the gas and its solubility.

Front 244

What's partial pressure in relation to henry's law?

Back 244

a higher partial pressure of a gas (O2) over a liquid (blood) causes more of the gas to stay in the solution

Front 245

What is solubility in relation to henry's law?

Back 245

because CO2 is 24x more soluble in blood than O2, much more CO2 is dissolved in blood plasma.