Exam 1 Heart Review

Question 1

Fibrous Skeleton of the Heart

Answer 1

• Separates atria & ventricles
• Anchors heart valves
• Provides electrical insulation between atria & ventricles
• Provides framework for attachment of
  myocardium

Question 2

Heart Wall

Answer 2

1. Pericardium outermost later (thin) is the membrane that surrounds and protects
   the heart. It ANCHORS heart to diaphragm with fibers. Fibrous layer of Parietal Pericardium - Outer and is tough tissue. Pericardial cavity contains about 30 ml of pericardial fluid Visceral Pericardium (aka epicardium) directly attached to myocardium deep to pericardial cavity
2. Myocardium middle layer Myocardium is responsible for pumping action and is
   made of two (2) layers of muscle. (Superficial and Deep) 95% of heart wall is made
   up of this
3. Endocardium innermost layer (thin) continuous with the endothelium of blood
   vessels

Question 3

External Surface of the Heart

Answer 3

Has Coronary, Ant, and Post Sulci. Has fat and blood vessels. Coronary sulcus is a large groove / deep on the outside of heart has fat separates atria from ventricles. Ant and Post
interventricular sulci external boundary separates RT and LT ventricles shallow

Question 4

Right Atrium

Answer 4

From right boarder of heart To lungs “Fossa
ovalis” After birth no “Foramen ovale” it
is before birth (normally). Deoxygenated 3
sources of blood. 1- Superior Vena Cava
2- Inferior Vena Cava 3- Coronary sinus.
Sends blood to right atrium through
tricuspid valve (rt atrioventricular valve).

Question 5

Blood flow through the Heart

Answer 5

1- Superior or Inferior vena cava
2- RT Atrium
3- Tricuspid Valve (RT AV valve)
4- RT Ventricle
5- Pulmonary Semilunar Valve
6- Pulmonary Trunk and Arteries
7- Lungs
8- Pulmonary Veins
9- LT Atrium
10. Bicuspid Valve (Mitral) (LT AV Valve)
11. LT Ventricle
12. Aortic Semilunar Valve
13. Ascending Aorta
14. Arch of Aorta
15 Systemic Circulation Start over to 1.

Question 6

Left Ventricle

Answer 6

Pumps Blood out to body therefore has
Thicker walls. Has Trabeculae carne,
receives blood from LT Atrium, Bicuspid
valve (mitral) has chordae tendineae
(fibers) that anchor valve to papillary
muscles. Left ventricle has a CIRCULAR
LUMEN pumps blood into aortic
semilunar valve against great pressure.

Question 7

Cardiac Valves

Answer 7

Fibrous skeleton around valves. Prevent
backflow of blood ensure a one-way flow. -> NOT ALL VALVES HAVE STRINGS OR
CHORDS (chordae tendineae) Semilunar valves (No chordae tendineae Nochords) Aortic Semilunar andPulmonary Semilunar

Bicuspid valves (left side) and Tricuspid
valves (right side) do have chords,

Question 8

Does blood flow back into the vena
cavae and coronary sinus during
atrial contraction?

Answer 8

The compression of the right atrium
during systole prevents this.

Question 9

When the ventricles contract
the —– valve close and the
—– valve are pushed open.

Answer 9

Tricuspid Right AV and Pulmonary Semilunar
or
Bicuspid (Mitral) Left AV and Aortic Semilunar

Question 10

Circulation of Blood

Answer 10

The pulmonary circulation transports
blood from the heart to the lungs and back
to the heart. The first blood vessel in the systemic circuit is the aorta.
The systemic circulation circuit receives blood from the left ventricle. The right side of the heart is the pump for the pulmonary circuit.

Question 11

Coronary Arteries

Answer 11

Right Coronary Artery
Anterior interventricular branch
Circumflex artery

Left Coronary Artery
Posterior interventricular branch
Marginal branch

Question 12

Cardiac Muscle Tissue

Answer 12

• bifurcated (branched) cells
• intercalated discs
• numerous large mitochondria
• striations

Question 13

Autorhythmic Cells of the
Heart

Answer 13

depolarize to threshold “spontaneously”
Due to slow Na+ Channel inflow

Question 14

Primary Pacemaker of the
Heart

Answer 14

Sino Atrial Node “SA Node”
Sets establishes basic rhythm of
Cardiac action potentials for heart beats
per minute

Question 15

Cardiac Conduction System

Answer 15

order of events
1- SA NODE
2- AV NODE
3- AV Bundle
4- Bundle Branches
5- Purkinje Fibers

Question 16

Cardiac Conduction System

Answer 16

• The AV node can take over the pacemaking task if the SA node is damaged.
• The pacemaking ability of the AV bundle alone is not sufficient to maintain homeostasis.
• Ectopic pacemakers may be stimulated by caffeine or nicotine
• Ach release by the parasympathetic division
  of the ANS decreases SA node
  depolarization

Question 17

Plateau phase of a cardiac
contractile action

Answer 17

• opening of voltage-gated slow Ca2+ channels
• release of Ca2+ from the sarcoplasmic reticulum.
• entry of Ca2+ from the interstitial fluid
• decreased permeability to K+ due to closing
  of some K+ channels

Question 18

Refractory Period of cardiac
muscle fibers

Answer 18

• Is a time interval during which another contraction is prevented.
• Is much longer than their contraction
  period.
• Prevents tetany and allows the heart to
  act as a pump.

Question 19

Cardiac Muscle

Answer 19

• Most of the ATP production is aerobic
• Most of the ATP used while at rest comes
  from oxidation of fatty acids
• ATP is produced from creatine phosphate
• O2 is passively transported across the
  sarcolemma.
• Lactic acid production increases during
  exercise.

Question 20

an electrocardiogram
(ECG or EKG) detects

Answer 20

• cardiomegaly (enlargement of the heart)
• ischemic coronary blood vessels
• disturbances of the conduction pathway
  of the heart.
• damage to certain regions of the heart

Question 21

QRS Complex

Answer 21

• ventricular depolarization
• atrial repolarization

Question 22

prolonged P-Q interval

Answer 22

A patient may have coronary artery
disease or rheumatic fever.

Question 23

Correlations between cardiac
contractions and ECG waves.

Answer 23

• Atrial systole begins immediately after P wave
• All chambers are relaxing during the period. between the T wave and the next P wave.
• Ventricular systole begins at the end of QRS complex.
• Atrial diastole occurs during the appearance of the QRS complex.
• Ventricular diastole follows the appearance of the T wave.

Question 24

A single cardiac cycle

Answer 24

• Lasts .8 sec (8/10 th) when the heart rate is 75 beats/minute.
• Forces blood from areas of lower pressure to areas of higher pressure.
• Occurs dependently of electrical activity
  in the heart.
• Includes all of the events associated with
  one heartbeat.

Question 25

Events occurs during Ventricular Systole

Answer 25

- **isovolumetric contraction** - ventricular pressure **rises** - **opening** of the SL valves

Question 26

Relaxation Period of the Cardiac Cycle

Answer 26

- It is a time when the atria are **relaxed** - It is a time that becomes **shorter** as the heart rate **increases.** - It is a time when the AV valves are **open**. - It is the time when the ventricles receive most of the blood from the **atria.** - It is a time when the SL valves are **closed.**

Question 27

End of Atrial Systole

Answer 27

amount of blood contained in a ventricle is the **end-diastolic volume** EDV

Question 28

Isovolumetric Contraction

Answer 28

During the cardiac cycle the interval during which cardiac fibers are contracting but not shortening. The intraventricular pressure increases, but the ventricular volume remains the same.

Question 29

Heart Sounds

Answer 29

Heart sounds- Lubb-dupp (lub-dup) a representation of the normal heart sounds as heard through the stethoscope. The first coincides with closure of the mitral and tricuspid valves; the second with closure of the aortic and pulmonary valves. **Closing of valves make heart sounds (heart beat).**

Question 30

Cardiac Output I

Answer 30

- HR x SV in each ventricle each minute **“Product of Stroke Volume and Heart Rate from each Ventricle”** - Is the volume of blood ejected from the **right** ventricle into the **pulmonary trunk** each minute. - Is the volume of blood ejected from the **left ventricle** into **aorta** the each minute.

Question 31

Cardiac Output II

Answer 31

**CO = EDV** 130 ML – ESV 60 ML = SV 70 ML X HR in 70 BPM) = 4900 ML = 4.9 L EACH ventricle **EDV=** End Diastolic Volume (Ventricles Full) **ESV=** End Systolic Volume (Ventricles Emptying but not completely empty) **SV=** amount leaving heart EDV-ESV=SV

Question 32

Cardiac Reserve

Answer 32

Amount of excess between Normal C.O. and Maximum C.O. 20L Max – 5L Normal = 15L Reserve

Question 33

Stroke Volume Regulation

Answer 33

- adjusting the **afterload**, the pressure that must be overcome to open an SL valve - adjusting the **contractility**, or strength of contraction of the heart at a given preload. - adjusting the **preload**, or degree of stretch on the heart before it contracts

Question 34

Frank-Starling law of the Heart

Answer 34

The greater the preload on cardiac muscle fibers, the greater the force of contraction will be.

Question 35

Edema

Answer 35

**Left Heart Failure** = Left ventricle failure or blockage, Results in Pulmonary Edema=Lung Fluid **Right Heart Failure** = Right ventricle failure or blockage, Results in Systemic or Peripheral Edema

Question 36

Regulation of Heart Rate I

Answer 36

- Nervous system control is originates in the cardiovascular center of the medulla oblongata. - Parasympathetic impulses travel to the heart primarily along the vagus (X) nerves. - The limbic system can influence the cardiovascular center of the medulla oblongata. - Proprio-, chemo-, and baroreceptors detect changes and influence the cardiovascular center. - Increased stimulation by the cardiac accelerator nerve increases heart rate.

Question 37

Regulation of Heart Rate II

Answer 37

- Ach - Decreases HR - Epinephrine - Increases HR - Norepinephrine - Increases HR - Hyponatremia - Increases HR - T3/T4 - Increases HR

Question 38

Regulation of Heart Rate III

Answer 38

Regular exercise tends to reduce resting heart rate in both males and females.

Question 39

Pectinate muscles

Answer 39

Internal walls of the right and left atria and auricles.

Question 40

Myocardial Infarction

Answer 40

- Results from an interrupted blood supply to part of the heart. - Causes death of part of the heart. - Is usually treated with anti-coagulation therapy.

Question 41

Isovolumetric Contraction

Answer 41

During the cardiac cycle the interval during which cardiac fibers are contracting but not shortening. The intraventricular pressure increases, but the ventricular volume remains the same.

Question 42

Right Atrium and Right Ventricle

Answer 42

Are located **anteriorly** in a heart in normal position.

Question 43

Plateau phase of a cardiac contractile action

Answer 43

- opening of voltage-gated slow Ca2+ channels - release of Ca2+ from the sarcoplasmic reticulum. - entry of Ca2+ from the interstitial fluid - decreased permeability to K+ due to closing of some K+ channels