The Heart and Body Systems (Unit 1)

Question 1

Myogenic?

Answer 1

Creates its own impulse

Question 2

Sino-Atrial Node?

Answer 2

Fires electrical signal causing both atria to contract, forcing blood into the ventricles. Also called ‘Pacemaker of the Heart’

Question 3

What causes more electrical impulses from the SA Node?

Answer 3

The medulla oblongata sends an impulse to the SA node via the sympathetic nervous system increasing heart rate and the impulse of the SA node

Question 4

Atrio-Ventricular Node?

Answer 4

Has a slight delay allowing for full atrial contraction before making the ventricles contract which ejects blood out of the heart through the semi-lunar valves. Also known as ‘Distributor of the Heart’

Question 5

Why does the AV Node have a slight delay?

Answer 5

Causes a slight delay in the spread of the electrical impulse to allow atria to fully contract

Question 6

Bundle of HIS?

Answer 6

Distributes the electrical impulse through the septum towards the Purkinje fibers

Question 7

Purkinje Fibres?

Answer 7

Continue the impulse causing a contraction of the ventricles

Question 8

What is the order of the
Conduction System?

Answer 8

The Sino-atrial node sends an impulse forcing blood into the ventricles after making the atria contract.
The atrioventricular node then delays the impulse and allows the atria to contract.
The impulse passes through the bundle of His which conducts the impulse from the AV node to the ventricles.
The bundle branches, which split into left and right branches carry the impulse along the through the septum.
The Purkinje fibers then spread the impulse throughout the ventricular walls and cause them to contract forcing blood out of the heart and around the body or to the lungs.

Question 9

What is stroke volume?

Answer 9

The volume of blood pumped out of the left ventricle every beat

Question 10

What is cardiac output?

Answer 10

The volume of blood pumped out the left ventricle every minute

Question 11

Heart rate?

Answer 11

Beats per minute

Question 12

Cardiac Output formula?

Answer 12

Cardiac Output= Heart Rate x Stroke Volume

Question 13

Ejection Fraction?

Answer 13

Volume of blood the heart pumps out with each contraction

Question 14

What is maximum stroke volume in a heart rate range?

Answer 14

40-60% of maximum heart rate

Question 15

How do you calculate max heart rate and heart rate range for an individual?

Answer 15

Max Heart Rate= 220-age
Max Heart Rate - Resting Heart Rate = Heart Rate Range

Question 16

What are the effects of the lack of exercise for Heart Disease, Cholesterol, Stroke and Blood Pressure?

Answer 16

Heart Disease- Atherosclerosis known as fatty deposits build up within coronary arteries, Atheroma known as blood clots build up in arteries

Cholesterol- Damage to heart over time, increase of LDL levels that cause cholesterol blockages

Stroke- Higher chance of strokes, after a stroke you find difficulty standing and have to use seated exercises, possibility of a hemorrhage

High Blood Pressure- High blood pressure causes strain on arteries and could potentially cause blockages in veins and arteries.

Question 17

What are the positives of daily exercise for combating cholesterol, high blood pressure and strokes?

Answer 17

Cholesterol- Exercise increases the HDL levels in your body and decreases the LDL levels in your body that causes cholesterol to form in arteries, typically need 150 minutes of exercise a week

Stroke- Prevents the chance of having a stroke significantly, exercise helps to stretch muscles and joints after a stroke using seated exercises

High Blood Pressure- Exercise really helps to lower blood pressure and in turn reduces strain on arteries, strengthens the heart so it doesn’t need to work as hard , however don’t start with HIIT workouts if suffering from High Blood Pressure

Question 18

What is the Cardiac Control Center?

Answer 18

In the medulla, which is part of our lower brain and it is used to regulate our heart beat

Question 19

What are the two strands that make up the autonomic nervous system and they’re functions?

Answer 19

Sympathetic Nervous System- when blood pressure is too low, the medulla sends impulses via the SNS to increase heart rate

Parasympathetic Nervous System- when blood pressure is too high the medulla sends impulses via the vagus nerve (PNS) to decrease heart rate. As it slows the spread of impulses from the SA node

Question 20

What are the three receptors and they’re functions?

Answer 20

Chemoreceptors-detect CO2- if high it sends impulses to the medulla and that sends nerve impulses to the SA node-increasing heart rate

Proprioceptors-detect increased movement -if high it sends impulses to the medulla and that sends nerve impulses to the SA node-increasing heart rate

Baroreceptors-detect high pressure- if high it sends impulses to the medulla and that sends impulses to the SA node-increasing heart rate

Question 21

What is the Hormonal Heart Control and what do the different hormones do?

Answer 21

Adrenalin- is secreted into the blood stream stimulating the SA node to increase heart rate and ventricular contraction, thus increasing stroke volume; equally it gives an anticipatory rise before beginning exercise

Acetylcholine- released by the parasympathetic nervous system causing heart rate to decrease after exercise counteracting all the previously secreted adrenalin

Question 22

What is Starling’s Law?

Answer 22

The relationship between the increase of venous return and an increase in stroke volume

e.g. Greater Contraction=Greater elasticity of heart chambers

Question 23

What are the Venous Return mechanisms?

Answer 23

Pocket Valves- unidirectional and one way valves to prevents the backflow of blood and direct blood flow to the heart

Skeletal Muscle Pump- veins are situated between the skeletal muscles. When they contract they squeeze blood back to the heart. If we suddenly stopped exercising the blood would pool in our veins so we should always use an active cool down

Respiratory Pump- during exercise, breathing becomes deeper and faster, changing pressure in the lungs squeezes blood back to the heart

Heart Suction Pump- After each beat the heart sucks in any close blood by squeezing the veins to force blood flow back to the heart

Question 24

What is the Vasomotor Control Centre?

Answer 24

This regulates blood flow, blood pressure and distribution of cardiac output through the body, Vascular Shunt is controlled by the VCC in the medulla oblongata, the brain will stimulate the sympathetic nervous system to vasodilate and vasoconstrict the pre-capillary sphincters and arterioles

Question 25

What are the percentages of blood flow to the specific body areas during rest and exercise?

Answer 25

At rest- 15-20% supplied to muscles and 80-85% supplied to the organs At exercise- 80-85% supplied to muscles and 15-20% supplied to organs

Question 26

What are some of the artery's characteristics?

Answer 26

Have thick layers to handle pressure Thick elastic walls Works with high blood pressure Take blood away from the heart

Question 27

What are some of the vein's characteristics?

Answer 27

Prevent backflow of blood with valves Are thinner to adapt to different pressures Muscles contract and squeeze the veins to push blood towards the heart

Question 28

What are some of the capillary's characteristics?

Answer 28

Small diffusion pathway Thin 1 cell thick walls Moist walls

Question 29

What is a cells vessel structure?

Answer 29

1. Tunica Externa 2. Tunica Media (thicker layer than the artery) 3. Tunica Intima/epithelium

Question 30

What is vasoconstriction and vasodilation?

Answer 30

Vasodilation-widening of arterial blood vessels Vasoconstriction-narrowing of arterial blood vessels

Question 31

What are pre-capillary sphincters?

Answer 31

Arterioles have a ring of muscle surrounding the entry to the capillaries called pre-capillary sphincters. They open and close to regulate blood flow to the capillaries

Question 32

How is oxygen transported?

Answer 32

97% of oxygen combines to form oxyhaemoglobin whilst 3% combines with plasma

Question 33

Where is oxygen concentration highest and lowest?

Answer 33

Haemoglobin is saturated when oxygen concentration is high e.g. lungs It gives up oxygen when there is a low concentration e.g. at working muscles there it will give oxygen to the mitochondria

Question 34

How is Co2 transported?

Answer 34

Co2 combines with water to form Carbonic acid after capillary diffusion. Transported in the form hydrogen carbonate being 70% It combines with Haemoglobin to form carbohaemoglobin 23% and plasma 7% This increases blood acidity and therefore helps dissociate oxyhaemoglobin

Question 35

What are the affecting factors of oxyhaemoglobin dissociation?

Answer 35

Temperature- when muscles and blood increase temperature due to exercise or movement it increases dissociation and it occurs more readily Partial Pressure of Oxygen Decrease- level of oxygen decrease will cause more dissociation of oxygen from the haemoglobin causing increased dissociation Partial Pressure of Co2 Increase- as Co2 levels rise so does dissociation as it needs to occur quicker Ph- more Co2 lowers the bloods acidity, so does lactic acid. This causes faster dissociation of oxygen from haemoglobin