Module 8: Circulatory System: Cardiac Cycle pt.1

Question 1

what are the main functions of the heart

Answer 1

Transport o2 and nutrients

Takes out wate and co2

Regulates body temp & pH

Transports+distributes hormones

Question 2

Superior vena cava

Answer 2

Deliver blood to heart from head and upper limbs

Question 3

Pulmonary artery

Answer 3

Passage where blood leaves right ventricle travel to lungs

Question 4

aorta

Answer 4

Blood leaving left ventricle travels through aorta and is distributed to entire body

Question 5

Right atrium

Answer 5

Recieves blood from body

Blood – high CO2, low O2

Right atrium pumps blood into right ventricle through right AV

Question 6

Recieves blood from body

Blood – high CO2, low O2

Right atrium pumps blood into right ventricle through right AV

Answer 6

Receive blood from lungs

Rich in O2 AND low in CO2

Left atrium pumps blood to left AV

Question 7

Right ventricle

Answer 7

Pumps blood into pulmonary artery

Question 8

Left ventricle

Answer 8

Pumps blood into the aorta

Question 9

Right AV (tricuspid) Valve

Answer 9

Makes sure blood will flow one way (right atrium to right ventricle)

Question 10

Left AV (bicuspid) Valve

Answer 10

Makes sure blood will flow one way (left atrium to left ventricle)

Question 11

Pulmonary Semilunar Valve

Answer 11

Makes sure blood will flow one way (right ventricle to pulmonary artery)

Question 12

Aortic Semilunar Valve

Answer 12

Makes sure blood will flow one way (left ventricle to aorta)

Question 13

Chordae Tendineae

Answer 13

Collagen cords attach valves to papillary muscles and valves

Prevent av valves from being pushed into the atria when the pressue in the ventricles is high

Question 14

Papillary Muscles

Answer 14

Extensions of ventricular muscles

Attached to chordae tendineae

When ventricles contract so do papillary muscles

AV valves held in place

Question 15

circulation through the heart

Answer 15

Blood enters at right atrium

From the right atrium, it passes through the right atrioventricular valve and into the right ventricle

When the right ventricle contracts, it ejects the blood out of the heart through the pulmonary valve and into the pulmonary artery to the lungs

After passing through the lungs, removing CO2, and picking up O2, the blood returns through the pulmonary vein to the left atrium

Blood enters the left ventricle through the left atrioventricular valve

When the left ventricle contracts, blood is ejected through the aortic valve into the aorta and out to the body

Question 16

2 types Myocardial cells

Answer 16

Contractile cells – similar to skeletal muscle

Nodal/conducting cells – similar to nerve

Question 17

contractile cells

Answer 17

Form most walls of atria and ventricles

Similar features to skeletal muscle

• Same skeletal proteins (Actin + Myosin
• Myofibrils surrounded in sarcoplasmic reticulum
• BUT Only one nucleus, lots more mitochondria

Extract lots of O2

Contractile cells are connected with intercalated discs

• Tight junction – bind cells together
• Gap junctions – allow movement of ions between myocardial cells (AP conduction)

Question 18

myocardial cells – nodal/conducting cells

Answer 18

Weak – not many contractile proteins

Used for AP

Self-excitatory and transmission system

Located: ?

Question 19

Sinoatrial node (SA node)

Answer 19

first area to depolarize (AP)

= PACE MAKER because it has the fastest spontaneous depolarization rate compared to other areas of the heart

Question 20

Self excitability AP pathway through heart

Answer 20

Sinoatrial node SA Node

Atrial-ventricular node AV node

Bundle of His

Bundle of Branches

Purkinje fibers

Question 21

movement of ions heart cells and APs

Answer 21

Self excitable

Na+ comes in (depolarize)

Ca++ also try to move in (depolarize)

K+ leaving (makes it hyperpolarize)
- K+ permeability decreases over time (makes it possible to make AP)

Na+/K+ pump pumps K+ into cell

Depolarize from –60 mV to –40mV

No neurons

Pace maker potential – sets heartbeat

Question 22

speed of ap through myocardial cells

Answer 22

Sa node - slowest

Atrial muscle – quickens

Av node – slows to ensure atria have finished contracting

Bundle of his – very fast
- Want AP to reach apex of the heart to contract first

Purkinje fibers

Ventricular muscle

Question 23

electrocardiogram

Answer 23

AP recorded – body fluid conducts electricity electrodes on skin detect ap

P-wave – depolarization atrial node

QRS complex – depolarization of ventricular muscle

T wave – repolarization of ventricular muscle