Week 9

Question 1

Heart

Answer 1

A Muscular organ located in the chest

Question 2

Parts of the Heart (Blood from the Body)

Answer 2

Vena Cava: Receives deoxygenated blood from the body via Veins and the Deoxygenated blood is Taken to the Right Atrium.

Right Atrium: Pumps Deoxygenated blood collected from the body into the Right Ventricle

Pulmonary Valve: Ensures deoxygenated blood flows from the Right ventricle into the Pulmonary arteries

Tricuspid Valve: Ensures blood only flows from the right Atrium to the right Ventricle

Right Ventricle: Contracts and Pumps blood into the Pulmonary arteries

Pulmonary Arteries: Carry blood to the lungs where it’s Reoxygenated

Question 3

Parts of the Heart (Blood from the Lungs)

Answer 3

Aorta: Oxygenated blood leaves the heart and flows around the body

Pulmonary Veins: Receives oxygenated blood from the lungs

Left Atrium: Contracts and Pumps blood into the Left Ventricle

Mitral Valve: Ensures Oxygenated blood flows from the left Atrium to the left Ventricle

Left Ventricle: Blood moves through the Aorta back out to the rest of the body

Aortic Valve: Ensures Oxygenated blood flows from the left Ventricle to the Aorta

Question 4

Heart Valves

Answer 4

• Ensures blood flow in the Correct direction through the chambers of the Heart
• Opening and Closing of valves are controlled by blood pressure changes

Question 5

Heart Sounds

Answer 5

Lub: First heart sound that heard is the Closing of the Tricuspid and Mitral Valves also known as Atrioventricular valves

Dub: Second heart sound is the Closing of the pulmonary and Aortic Valves also known as Semilunar Valves

Question 6

Cardiac Conduction System Parts

Answer 6

Sinoatrial Node (SA Node): Generates an Electrical signal that causes Atria to Contract.

Atrioventricular Node (AV Node): Conduct impulse from the Atria to Contract

Atrioventricular Bundle: AV node receives signals from the SA node and passes them there

Left and right Bundle Branches: AV bundle is divided into left and right bundle branches, which conduct impulses towards the apex of the heart

Purkinje Fibers: Send impulses to the ventricle to Contract and Pump blood

Question 7

Intrinsic Conduction System (Electrocardiogram-ECG)

Answer 7

P Wave(1st from left): Contraction/Depolarization of Atria

PQ Segment: Signal Slows while Left and Right ventricle fill with blood

Q Wave (Small dip from left): Depolarization of Interventricular Septum

R Wave (Big Jump): Contraction/Depolarization of Left Ventricle

S Wave (A dip after the jump): Contraction/Depolarization of Right Ventricle

T Wave (A small curve after second dip): Ventricles Relax

Question 8

Cardiac Cycle:
-Systolic Blood Pressure
-Diastolic Blood Pressure

Answer 8

Cardiac Cycle: All events associated with blood flow through the heart during one complete heartbeat

Systolic Blood Pressure: Pressure in Arteries when Heart beats

Diastolic Blood Pressure: Pressure in Arteries when Heart rests

Question 9

Cardiac Cycle Parts (In Order)

Answer 9

Atrial Diastole:
All heart muscles in relaxation
All valves are closed
Blood returning to atria

Atrial Systole:
Atria in contraction
All valves are open
Blood to ventricles

Ventricular Systole:
Ventricles in contraction
Semilunar valves are open
Blood passing to arteries

Ventricular Diastole:
All heart muscles in relaxation
All heart valves are closed
Blood returning to atria

Question 10

Cardiac Output

Answer 10

The amount of blood pumped by each ventricle each minute.

Cardiac output (mL/min) = Heart rate (beats/minute) × Stroke volume (mL/beat)

Question 11

Heart rate

Answer 11

Numbers of heart beats per minute

Question 12

Stroke volume

Answer 12

Volume of blood pumped out by one ventricle each beat

Question 13

Factors affecting Stroke volume

Answer 13

1) Contractility: If the heart is contracting with more force, it is going to be able to pump more blood, increasing stroke volume which will in turn increase cardiac output.

2) Preload: Amount of blood in heart before it contracts. As preload increases, there is more blood to be
pumped, increasing cardiac output.

3) Afterload: Pressure the heart must overcome before the semilunar valve can open, and eject blood. Ejection of blood from the heart begins when pressure in the left ventricle exceeds the pressure in the aorta. At that point, the higher pressure in the ventricles causes blood to push the aortic valve open.

Question 14

Blood vessels

Answer 14

Main types of Blood vessels are Arteries/Veins and Capillaries

Walls of Arteries and Veins have three layers

Capillaries have a single layer of endothelial cells to allow oxygen and nutrients to readily pass through

Question 15

Layers of Arteries and Veins

Answer 15

Lining consists of Endothelium, a single layer of cells

Middle layer consists of Muscles and elastic fibers

Outer layer is made of connective tissue with elastic fibers

Question 16

What are Veins

Answer 16

Vessels that carry deoxygenated blood to the heart from parts of the body

Question 17

What are Arteries

Answer 17

Large thick-walled vessels that carry oxygenated blood away from heart to body

Question 18

What are Capillaries

Answer 18

Tiny thin-walled vessels that connect arteries and veins and is also a sit of exchange between blood and surrounding tissues.

Question 19

Blood Pressure

Answer 19

Blood pressure is force of blood pressing against walls of blood vessels or arteries

Low Blood Pressure: Organs do not receive adequate blood

High Blood Pressure: Damage inner lining of blood vessels and eventually lead to heart diseases/stroke

Question 20

Mean Arterial Pressure Equation (MAP)

Answer 20

MAP= Diastolic BP + 1/3 * (Systolic BP - Diastolic BP)

Question 21

Systolic Blood Pressure (Increase)

Diastolic Blood Pressure (Decrease)

Answer 21

Maximum pressure exerted on Arterial walls when heart is contracting

Maximum pressure exerted on arterial walls when heart is relaxing

Question 22

Factor Affecting MAP

Answer 22

1.) Total Peripheral Resistance (TPR)
- Vasodilation reduces TPR.
- Vasoconstriction increases TPR.

2.) Cardiac Output (Dependent on Heart Rate, Stroke Volume, and Contractility)
- The amount of blood pumped per minute by each ventricle. The higher the cardiac output, the higher the MAP, as there is more blood being pumped through the vessels.

Question 23

Baroreceptor Reflex

Answer 23

Rapid Negative mechanism that maintains blood pressure at stable levels. They are stretch receptors that detect decrease or increase in tension

Question 24

Baroreceptor Reflex (Increased Blood Pressure/Tension)

Answer 24

Baroreceptor send signals to the cardiovascular and vasomotor regulatory centers.

Parasympathetic response increases=Decreased heart rate

Sympathetic response Increases=Decreases heart rate and stroke volume

Blood vessels vasodilate=Decrease blood pressure

Question 25

Baroreceptor Reflex (Deceased Blood Pressure/No Tension)

Answer 25

Baroreceptor send signals to the cardiovascular and vasomotor regulatory centers. Parasympathetic response Decreases=Increased heart rate Sympathetic response Decreases=Increases heart rate and stroke volume Blood vessels vasoconstrict=Increase blood pressure

Question 26

Renin-Angiotensin Mechanism

Answer 26

Influences blood volume and pressure by regulating the release of aldosterone and thus Na+ and water reabsorption by the kidneys

Question 27

Renin (Decreased Blood Pressure)

Answer 27

Decrease in the stretch of the wall of the aorta and carotid bodies. Baroreceptor reflex will detect change and trigger release f renin (enzyme) in the kidneys

Question 28

Angiotensin 1

Answer 28

Renin cleaves angiotensinogen into angiotensin 1 Angiotensin 1 is converted into angiotensin 2 by angiotensin converting enzyme (ACE)

Question 29

Angiotensin 2

Answer 29

A Vasoconstrictor: increases peripheral resistance and decreases size of blood vessels=increase in blood pressure. Increase ADH release by the Posterior pituitary ADH increases water reabsorption by kidneys=increase in blood volume=increase blood pressure

Question 30

Aldosterone

Answer 30

Angiotensin 2 stimulates secretion of aldosterone by adrenal glands Aldosterone promotes Na+ and ADH reabsorption in the kidneys, results in an increase in water reabsorption= increase in blood volume and blood pressure

Question 31

Autoregulation

Answer 31

Regulation of blood occurs with vasoconstriction and vasodilation of the smooth muscles of blood vessels Ability of an organ to maintain constant blood flow despite changes in pressure to optimize the need for oxygen and nutrients

Question 32

Factors impacting Autoregulation -Myogenic -Metabolic

Answer 32

Myogenic: Stimulus: Increased blood pressure Response: Vasodilation=decrease blood pressure Stimulus: Decreased Blood Pressure Response: Vasoconstriction: Increased blood pressure Metabolic: Stimulus: Decreased PO2; Increased CO2;H+ Response: Vasodilation

Question 33

Vasodilation

Answer 33

Blood vessels widen allowing greater flow of blood Decreased Blood pressure

Question 34

Vasoconstriction

Answer 34

Blood vessels constrict preventing greater flow of blood Increases blood pressure

Question 35

Capillary Exchange

Answer 35

Smallest Blood Vessels Tiny pores that allow water and small solutes to pass, but not larger molecules to pass Fluids, nutrients and gases (O2) move out of the arterial ends of capillaries into cells Waste, fluid and gases (CO2) re-enters capillaries from cells

Question 36

Pressure Gradient

Answer 36

Maintained by the heart's pumping action and the resistance offered by the blood vessels.

Question 37

Arterial System

Answer 37

A high pressure system because it receives blood directly from the heart, which ejects blood into the arteries during systole (ventricular contraction)

Question 38

Why are Arteries referred to as pressure Reservoirs

Answer 38

Because of their elastic and muscular walls which allow them to store and maintain blood pressure generated by the heart.

Question 39

Venous System

Answer 39

A low pressure system because blood has lost much of its initial energy as it passed through the resistance of the capillaries.

Question 40

Why are Veins referred to as volume reservoirs

Answer 40

Because of their thin and compliant (stretchable) walls which allow them to store a large volume of blood at relatively low pressure.

Question 41

Venous Returns

Answer 41

Refers to the process of blood flowing back to the heart through the veins. Venous return mechanisms help ensure blood returns to the heart efficiently, despite the the challenge of low venous pressure, especially from lower parts of the body against gravity.

Question 42

Three Key Mechanisms that assist with Venous Return

Answer 42

-Vein Valves: Veins contain one-way valves that prevent blood from flowing backward. These valves ensure unidirectional blood flow toward the heart, even against gravity. -Skeletal Muscle Pump: Contraction of skeletal muscles compresses nearby veins. The compression propels blood toward the heart due to the presence of one-way valves in veins, which prevent backflow. -Respiratory Pump: During inhalation, the diaphragm moves downward, increasing abdominal pressure and decreasing thoracic pressure. This pressure gradient helps push blood from the abdominal veins into the thoracic veins and then into the heart.