the heart

Question 1

what is myogenic

Answer 1

Myogenic is the capacity of the heart to generate its own impulses at rest.

Question 2

whats the Sympathetic system

Answer 2

A part of the automatic nervous system that speeds up heart rate

Question 3

whats the Parasympathetic system

Answer 3

A part of the automatic nervous system that decreases heart rate.

Question 4

what is Medulla oblongata

Answer 4

The most important part of the brain as it regulates processes that keep us alive as breathing and heart rate.

Question 5

what are Chemoreceptors

Answer 5

Tiny structures in the carotid arteries and aortic arch that detect changes in blood acidity caused by an increase or decrease in the concentration of carbon dioxide.

Question 6

what are Baroreceptors

Answer 6

Special sensors in tissues in the aortic arch, carotid sinus, heart and pulmonary vessels that respond to changes in blood pressure to either increase or decreases heart rate.

Question 7

what are Proprioceptors

Answer 7

Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movements

Question 8

whats Adrenaline

Answer 8

A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate.

Question 9

whats Stroke volume

Answer 9

The volume of blood pumped out by the heart ventricles in each contraction.

Question 10

whats the Diastole phase

Answer 10

When the heart relaxes to fill with blood.

Question 11

whats the Ejection fraction

Answer 11

The percentage of blood pumped out by the left ventricle per beat.

Question 12

what do the Mechanoreceptors do

Answer 12

detect muscle contraction

Question 13

stroke volume

Answer 13

the volume of blood pumped out by the heart ventricles in each contraction

Question 14

heart rate

Answer 14

The number of times the heart beats per minute

Question 15

Cardiac output

Answer 15

The volume of blood pumped out by the heart ventricles per minute

Question 16

Ejection fraction

Answer 16

The percentage of the blood pumped out by the left ventricle per beat

Question 17

whats cardiovascular drift

Answer 17

the progressive increase in heart rate and decrease in stroke volume that begins after approximately 10 min of prolonged moderate-intensity exercise

Question 18

factors in cardiovascular drift

Answer 18

starts after ten mins
heart/pulse rate increases
decrease in stroke volume / ejection fraction
fluid lost as sweat

plasma is reduced
reduced venous return
starlings law
cardiac output increase due to more energy to cool the body

Question 19

what is starlings law

Answer 19

the stroke volume of the left ventricle will increase as the left ventricular volume increases due to the myocyte stretch causing a more forceful systolic contraction.

Question 20

starlings law how it works

Answer 20

Increased venous return —> greater diastolic filling of the heart —> cardiac muscle stretched —> more force of contraction —> increased ejection fraction

Question 21

what are pukinje fibres

Answer 21

specialised cardiac tissue which spreads a cardiac impulse throughout the myocardium, causing the ventricles to contact

Question 22

whats the sinoatrial node (SAN)

Answer 22

a mass of specialised cardiac muscle fibres located in the right atrium responsible for emitting the cardiac impulse. also known as the pacemaker of the heart

Question 23

whats the atrioventricular node

Answer 23

a mass of conducting cells located in the right atrial wall which acts as a distributor passing the cardiac impulse down through the septum

Question 24

whats bundle of HIS

Answer 24

two branches of the conduction system of the heart that run down the entire length of the septum

Question 25

whats the order that cardiac impulses travel through the conduction structures within the heart

Answer 25

• myogenic
• sinoatrial node
• atrioventricular node
• systole
• Bundle of HIS
• punkinje fibres

Question 26

what do chemoreceptors do

Answer 26

sense an increase in CO2 and increase HR

Question 27

what do baroreceptors do

Answer 27

sense and increase in blood pressure and decrease the HR

Question 28

what do proprioceptors do

Answer 28

sense an increase in muscle movement and increase the HR

Question 29

cardiac cycle order

Answer 29

• cardiac impulse from the SA node causes atrial diastole
• rising pressure forces the AV valves to open
• ventricular diastole
• atrial systole
• Av node spreads excitation through the valves
• ventricles contract causing an increase in ventricular pressure
• semi lunar valves are forces open, AV valves remain closed
• blood is forced into the aorta and pulmonary arteries
• semi lunar close to prevent back flow of the blood