4. Cardiovascular System

Question 1

Perfusion Status

Answer 1

• Pulse
• BP
• Skin color

Question 2

What underpins cardio measurements

Answer 2

• heart muscle contraction/relaxation
• blood vessel resistance
• blood volume

Question 3

Location of heart

Answer 3

I’m the mediastinum

Question 4

Heart Chambers

Answer 4

R/L Atrium

R/L Ventricle

Question 5

Base vs. apex of the heart

Answer 5

Base is the top and Apex is the bottom for some reason

Question 6

Inter-ventricular Septum

Answer 6

Middle wall of the heart between the ventricles

Question 7

What are the atrioventricular valves?

Answer 7

Right: Tricuspid
Left: Bicuspid/mitral

Question 8

What are the semilunar valves?

Answer 8

Right: pulmonary valve
Left: aortic valve

Question 9

Where do coronary veins converge to from the myocardium?

Answer 9

Coronary sinus/Right atrium

Question 10

The cardiac cycle

Answer 10

Full complex

• electrical events
• mechanical events
• pressure changes
• heart sounds
• volume changes

Question 11

Cardiac conducting system

Answer 11

• intrinsic conduction system
• autorhythmic nodal cells
• pacemaker

Question 12

Nodes of the heart

Answer 12

SA - Sinus
AV - Junctional
R/L Bundle Branches
Purkinje Fibers

Question 13

Action Potentials of Autorhythmic Cells

Answer 13

-60mv: Na+ entry: slow depolarization
(Pacemaker Potential)
-40mv threshold potential
-Ca2+ entry: fast depolarization to +mv (Action Potential)
-K+ exit: repolarization back to -60mv

Question 14

The 2 Cardiac Muscle Cells Involved Cardiac Contraction

Answer 14

1. Conducting System

2. Contractile cells

Question 15

Cardiac Muscle Cells

Answer 15

• Striated, one nucleus

- Branching Cells: joined by intercalated discs, communicate via gap junctions, quick cell-to-cell communication

Question 16

Action potential of cardiac muscle (contractile) cells

Answer 16

Depolarization: From -90mv, Na+ influx shoots cell up to +30mv

Plateau Phase: due to Ca3+ influx through slow Ca2+ channels, this keeps the cell depolarized.

Repolarization: due to Ca2+ channels inactivating and K+ channels opening, this allows K+ efflux, which brings the membrane potential back to its resting voltage

Question 17

Mechanical Events

Answer 17

1. Atrial systole (contraction)
2. Ventricular systole (contraction)
3. Diastole (relaxation)

Question 18

Heart Sounds

Answer 18

S1: AV valves (Lub)
S2: Semilunar Valves (Dub)

Question 19

Stroke Volume

Answer 19

“Per stroke”

Amount of blood pumped out of ventricle (~70ml) in one beat

Question 20

Cardiac Output

Answer 20

Amount of blood ejected from the left or right ventricle into the aorta or pulmonary trunk each minute

CO (mL/min) = SV (mL/beat) x HR

Question 21

Regulation of stroke volume

Answer 21

1. Preload
2. Contractility
3. Afterload (pressure to overcome ventricles to eject blood, e.g. ⬆️BP)

Question 22

3 tunics of blood vessel

Answer 22

1. Tunica internia
2. Tunica media
3. Tunica externia

Question 23

Continues capillaries

Answer 23

Tightly bound, small gaps.

Skin, muscle

Question 24

Fenestrated Capillaries

Answer 24

Larger pore, facilitated exchange (kidneys, small intestine)

Question 25

Albumin

Answer 25

Protein in blood that takes/keeps water back into vessel (oncotic pressure)

Question 26

Lymphatic vessels

Answer 26

Remove excess fluid

Question 27

Factors in vascular/peripheral resistance

Answer 27

1. Size of blood vessel lumen 2. Blood viscosity 3. Total blood vessel length The higher the resistance the smaller the blood flow

Question 28

Venous return

Answer 28

Return of blood through veins with help of valves, resp pump and skeletal muscle pump

Question 29

Short-term control of BP

Answer 29

1. Vasometer centre (medulla oblongata) 2. Barotrceptors 3. Chemical-hormonal

Question 30

Long term control of BP

Answer 30

Renin-angiotensin-aldosterone system

Question 31

Vasomotor center

Answer 31

Regulates blood vessel diameter - Vasoconstriction: ⬆️BP - Vasodilation: ⬇️BP Sympathetic Nervous System: vasoconstriction

Question 32

Baroreceptors Reflex

Answer 32

Pressure receptor

Question 33

RAAS

Answer 33

Kidneys: Renin, released when lower blood volume is detected Liver: Angiotensin, is converted by renin into A1 Lungs: Angiotensin converting enzyme (ACE), converts A1 to A2

Question 34

Angiotensin 2

Answer 34

- Leads to vasoconstriction - goes back to kidney to cause release of hormone, aldosterone, which causes retention of Na and H2O - then goes to hypothalamus to cause thirst response - then goes to posterior pituitary gland to cause a release of Antidiuretic hormone (ADH), causing production urine

Question 35

Erythrocytes

Answer 35

Red Blood Cells - Transport O2 & CO2 - Lack nucleus and most organelles to make space for hemoglobin (iron-containing oxygen-transport metalloprotein)