Biology *1080 - Lecture 15

Question 1

What is Contraction Called in the Cardiac Cycle

Answer 1

Systole

Question 2

What is Relaxtion called in the cardiac cycle?

Answer 2

Diastole

Question 3

What is “healthy” blood pressure levels?

Answer 3

120/80

Question 4

What does 120 BP represent?

Answer 4

Systole BP

Question 5

What does 80 BP represent?

Answer 5

Diastole BP

Question 6

What is Diastolic Arterial Pressure called?

Answer 6

Afterload

Question 7

What is afterload?

Answer 7

The pressure against which the heart must work to eject blood during systole (diastolic pressure)

Question 8

What happens during early diastole?

Answer 8

Atria and Ventricles are relaxed and fill passively (i.e, at rest)

Question 9

What happens during later diastole?

Answer 9

Ventricles are still relaxing and filling passively

Question 10

What happens during atrial systole?

Answer 10

Both atria contract and force blood into ventricles

Question 11

What happens during Ventricular systole?

Answer 11

Both ventricles contract
- The right ventricle forces blood into the pulmonary trunk
- The left ventricle forces blood into the aorta

Question 12

What is the Cardiac Cycle?

Answer 12

The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next.

Question 13

What do Neural and Endocrine signals control?

Answer 13

The strength and rate of heart contractions

Question 14

What is sympathetic innervation?

Answer 14

Increased Heart Rate (norepinephrine)

Question 15

What is parasympathetic innervation?

Answer 15

Decreased Heart Rate (acetylcholine)

Question 16

What does epinephrine do?

Answer 16

Increase strength of each contraction

Question 17

How much can the heart increase during exercise?

Answer 17

By nearly 200 bpm

Question 18

How much does cardiac output increase during exercise?

Answer 18

5 to 25L/min

Question 19

What does Cardiac muscle consist of?

Answer 19

Cardiomycocytes that are connected by intercalated discs

Question 20

What is Electric Signal Propogated by?

Answer 20

Nodes, nerves, intercalated discs

Question 21

What are the Nodes in the heart?

Answer 21

• SA node - where electrical impulses are generated
• AV (atrioventricular) node

Question 22

What are the nerves in the heart?

Answer 22

• Bundle of His
• Bundle Branches
• Purkinge Fibres

Question 23

What are the intercalated discs?

Answer 23

• Gap Junctions

Question 24

What is Arrhythmia?

Answer 24

An irregular heartbeat:
- Occurs when the electrical signals that tell the heart to beat don’t work properly.
- The heart may beat too fast or too slow.

Question 25

What is Abnormal sinoatrial (SA) node firing?

Answer 25

The firing of nodes at different rates, resulting in tachycardia, bradycardia

Question 26

Tachycardia

Answer 26

Too fast

Question 27

Bradycardia

Answer 27

Too Slow

Question 28

What do blocks cause?

Answer 28

• Slow down or prevent signal propagation from atria to ventricles
• Ventricles can contract independently (depolarization)

Question 29

How are fibrillations caused?

Answer 29

When cells depolarize independently

Question 30

What is Atrial fibrillation?

Answer 30

A quivering or irregular heartbeat

Question 31

What is ventricular fibrillation? (Grey’s Anatomy - V-fib)

Answer 31

A random depolarization where the heart can not send oxygen rich blood to the body

Question 32

What is Atherosclerosis?

Answer 32

Narrowing of arteries due to calcified fatty deposits (plaque) and thickening of the wall

Question 33

What can atherosclerosis lead to?

Answer 33

Heart Attack or Stroke

Question 34

Factors that Cause Atherosclerosis

Answer 34

Elevated blood lipids, hypertension, inflammatory mediators

Diet (sodium, potassium, saturated/trans fats)

Smoking, physical inactivity, obesity/diabetes

Age, genetics

Question 35

What is an Angioplasty?

Answer 35

A catheter and balloon are threaded into the coronary artery to the point of blockage

The balloon is inflated and the plaque is pushed into the artery walls

Question 36

What is a Bypass Surgery?

Answer 36

A vein is taken from an arm or leg; one end attached above the blockage and the other below

Question 37

What is hypertrophy?

Answer 37

An increase and growth of muscle cells in the heart (heart enlarges)

Question 38

Why do endurance athletes experience hypertrophy?

Answer 38

Mostly an increase in LV chamber to allow for an increase in cardiac output

Question 39

Why do weightlifters experience hypertrophy?

Answer 39

Mostly an increased LV wall and septum thickness (need to overcome increased afterload)

Question 40

What is the bad hypertrophy?

Answer 40

High blood pressure and narrowing of the aortic valve (the heart must work harder, increasing in size to overcome this)

Question 41

What is systolic blood pressure?

Answer 41

When the ventricles contract, sending blood into the arteries (max. pressure)

Question 42

What is diastolic blood pressure?

Answer 42

When the heart relaxes between beats (minimum pressure)

Question 43

What is considered a crisis for blood pressure?

Answer 43

Higher then 180/120

Question 44

What happens during vasoconstriction?

Answer 44

Alpha-receptors are located in arteries

Norepinephrine and epinephrine bind to A2 (adrenergic) receptors

Causes arteries to constrict and increases blood pressure

Question 45

What happens during vasodilation?

Answer 45

Blood vessels in skeletal muscles lack alpha receptors

Norepinephrine and epinephrine bind to B2 adrenergic receptors found in arteries of skeletal muscle

This dilates vessels so they can receive increased blood flow

Question 46

Does blood pressure increase DRAMATICALLY during exercise?

Answer 46

No

Question 47

Why does BP not increase dramatically during exercise?

Answer 47

Dilation of vessels to skeletal muscle and heart increases blood flow to muscles (B2 receptors)

Constriction of vessels to the kidneys decreases blood flow to the organs (A2 receptors)

Dilating vessels in the muscle decreases blood flow resistance therefore BP does not increase

Question 48

Why does resistance training cause dramatic increases in blood pressure?

Answer 48

By holding your breath, your increasing your intrathoaracic pressure (Valsalva maneuver) which temporality raises BP and slows heat rate