8.5 The Heart

Question 1

What are the atria?

Answer 1

upper chambers of the heart

Question 2

Describe the muscular walls of the atria:

Answer 2

THIN

LITTLE PRESSURE/FORCE required

to push blood over short distance into ventricles

Question 3

What are the ventricles?

Answer 3

lower chambers of the heart

Question 4

Describe the muscular walls of the ventricles:

Answer 4

RIGHT: thinner&raquo_space; less pressure/force required to push blood over shorter distance to lungs.

LEFT: thicker&raquo_space; more pressure/force required to push blood over longer distance to body.

Question 5

What are the valves in the heart and what are their functions?

Answer 5

BICUSPID: LA ⟶ LV

TRICUSPID: RA ⟶ RV

SEMILUNAR: V’s ⟶ out

Question 6

What is the function of the tendinous cords?

Answer 6

anchors valves

preventing them from inverting

Question 7

What is the function of septum?

Answer 7

SEPARATES oxygenated + deoxygenated blood

Question 8

What veins are involved with the heart?

Answer 8

PULMONARY: lungs ⟶ heart

VENA CAVAE:

superior: upper body ⟶ heart
inferior: lower body ⟶ heart

Question 9

What arteries are involved with the heart?

Answer 9

PULMONARY artery: heart ⟶ lungs

AORTA: heart ⟶ body

CORONARY ARTERIES: supply heart muscle

Question 10

What is the cardiac cycle?

Answer 10

series of events

in 1 heart beat

diastole + systole

Question 11

What is diastole?

Answer 11

PHASE of cardiac cycle

when heart muscle RELAXES

Question 12

What is systole?

Answer 12

PHASE of cardiac cycle

when heart muscle CONTRACTS

split into atrial systole + ventricular systole

Question 13

What occurs during diastole?

Answer 13

muscle are relaxed

chambers FILL with blood

Question 14

What occurs during atrial systole?

Answer 14

atria contract

PRESSURE pushes blood through atrioventricular (bi/tricuspid) valves ⟶ ventricle

Question 15

Which systole occurs first?

Answer 15

atrial

Question 16

What occurs during ventricular systole?

Answer 16

ventricles begin to contract
- pressure builds, closes AV valves, not enough pressure to open semilunar valves. All valves closed @ this point.

pressure builds enough to open semilunar valves

atria + ventricles relax
- semilunar valves shut.

Question 17

The left and the right side of the heart fill and empty…

Answer 17

together

Question 18

Describe the rhythm of the heart in term of electrical impulses:

Answer 18

1. Electrical impulse originates in SAN.
   
   • atria contact
   • layer of conducting tissue prevents signal passing to ventricles.
2. Electrical impulse travels to AVN
   
   • slight PAUSE to allow atria to finish contracting.
3. Bundle of his carries electrical impulse ⟶ APEX, branches into walls
   
   • ventricles contract from bottom

Question 19

What is the normal heart rate?

Answer 19

70bpm

Question 20

What heart rate is tachycardia?

Answer 20

> 100bpm

Question 21

What is an ectopic heartbeat?

Answer 21

extra beat outside rhythm

Question 22

What is atrial fibrillation?

Answer 22

atria constantly relaxing + contracting

blood circulates less efficiently

Question 23

What is an ecg trace of a single heartbeat made from?

Answer 23

P wave
Q R S complex
T wave

Question 24

What does the P wave of a heartbeat ecg indicate?

Answer 24

electrical impulse travelling through atria

Question 25

What is the QRS complex?

Answer 25

electrical impulse travelling through ventricles

Question 26

What does the T wave of a heartbeat ecg indicate?

Answer 26

dissipation of electrical impulse / recovery wave

Question 27

What does an ecg measure to create a trace of the heartbeat?

Answer 27

changes in SKIN’S ELECTRICAL CONDUCTIVITY

as a result of HEART ACTIVITY.