Chapter 4 Flashcards

0
Q

What are the 4 chambers of the heart and where are they located?

A

Two atria at the top, two ventricles at the bottom

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1
Q

What are the 3 layers of the heart?

A

Pericardium, myocardium, endocardium

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2
Q

Where is the bicuspid valve located?

A

Between left atrium and left ventricle

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3
Q

Where is tricuspid valve located?

A

Between right atrium and right ventricle

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4
Q

What is the role of the semi lunar valves?

A

Preventing backflow of blood into the heart from the pulmonary artery and aorta, and to only allow blood to flow in one direction through the heart

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5
Q

Where are the venae Cavae and pulmonary artery located on the heart?

A

Right side

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6
Q

Where the pulmonary veins and aorta located on the heart?

A

Left side

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7
Q

Describe how a cardiac contraction is initiated

A

Impulse from SA node travels down atrial mycardium until it reaches AV node in wall of atrial septum. Atrial walls then contract. AV node then conducts impulse through bundle of his to Purkinje fibres which cause both ventricles to contract

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8
Q

What is diastole?

A

Relaxed heart muscle allows chambers to fill with blood. Cuspid valves open, semilunar closed.

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9
Q

Describe the 2 types of systole

A

Atrial systole, SA node impulse causes atria to force blood past cuspid valves into the ventricles, semilunar closed.
Ventricular systole, impulse reaches AV node, cuspid valves close, semilunar open, blood pushed out into pulmonary artery

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10
Q

Give formular for MHR

A

220-age

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11
Q

Describe the HR responses to exercise

A

Anticipatory rise due to adrenaline
Sharp rise in initial anaerobic work due to proprioreceptor stimulation
Steady state and recovery of o debt
Continued high hr due to maximal workloads
Rapid recovery due to cessation of proprioreceptive stimuli
Slow recovery as metabolite are cleared

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12
Q

Describe the SV responses to exercise

A

Anticipatory rise due to adrenaline
Increase as exercise commences, due to increased venous return and increased myocardial contraction
As intensity increases SV may drop slightly, but an increase in hr will correct this and level it out

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13
Q

List the 3 neural control factors

A

Chemoreceptor reflexes
Baroreceptor reflexes
Proprioceptor reflexes

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14
Q

What are Chemoreceptor reflexes?

A

Receptors in blood vessels which detect chemical changes in blood

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15
Q

What are proprioceptor reflexes?

A

Found in muscle spindles, respond to mechanical stimuli

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16
Q

What are baroreceptor reflexes?

A

Receptors in blood vessels detect changes in blood pressure

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17
Q

What are the hormonal factors affecting hr? Describe their effect

A

Noradrenaline and adrenaline accelerate hr and increase strength of ventricular contraction
Acetylcholine slows hr
Thyroid and glucagon increase hr
Increased glucagon levels assist breakdown of glycogen to make glucose to fuel muscular contractions

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18
Q

What are the intrinsic factors affecting venous return

A

Myocardial temperature, which affects the speed of impulse transmission and hence heart rate

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19
Q

Define venous return

A

The volume of blood returning to the heart during each cardiac cycle

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20
Q

What is the sympathetic influence on the heart rate?

A

SNS releases adrenaline and noradrenaline onto sa node to speed up hr

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21
Q

What is the parasympathetic influence on hr?

A

PNS releases acetylcholine on SA node to slow HR

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22
Q

What are the long term adaptations of the heart to aerobic exercise?

A

Hypertrophy, which increases SV
Bradycardia
HR will decline much faster than for an untrained person after exercise

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23
Q

What is he venous return mechanism?

A

The process by which blood returns back to the heart

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24
Q

What is the skeletal muscle pump?

A

Where contracting skeletal muscle squashes veins, forcing blood back to the heart

25
Q

What is the respiratory pump?

A

Changes in pressure in thoracic and abdominal cavities during breathing, causing nearby veins to compress and push blood back to he heart

26
Q

What are pocket valves?

A

Valves that ensure blood only flows in one way

27
Q

What are the components of the venous return mechanism?

A

Gravity
Skeletal muscle pump
Respiratory pump
Pocket valves

28
Q

What is the role of the vasomotor centre?

A

To control blood pressure and flow

29
Q

What is vasomotor control?

A

The ability of muscular arteries and arterioles to change shape due to receptors

30
Q

What occurs in non active tissue to control blood flow?

A

Impulses from sympathetic nerve cause vasoconstriction to pre capillary sphincters at the openings to non active tissue, therefore less blood flows into the non active tissue

31
Q

What occurs in active tissue to control blood flow?

A

Pre capillary sphincters open to allow more blood in, due to sympathetic stimulation.

32
Q

What is the vascular shunt mechanism?

A

The process by which during exercise blood is diverted from most organs and transported to skeletal muscle

33
Q

How is most oxygen carried by blood?

A

Haemoglobin in red corpuscles

34
Q

Why is the body able to pick up 10 times more oxygen during exercise than at rest?

A

Exercise causes a small increase in pulmonary blood pressure, distorting red blood corpuscles in alveolar capillary system

35
Q

What is our oxygen reserve?

A

The 75% of available oxygen we don’t use at rest

36
Q

How and in what percentages is CO2 transported in venous blood as

A

Carbonic acid 70%
Carboaminohaemoglobin 23%
CO2 dissolved in blood plasma 7%

37
Q

Define blood pressure

A

Force per unit area exerted by the blood on the inside walls of blood vessels

38
Q

What are the two types of blood pressure?

A

Systolic - highest

Diastolic

39
Q

What is the formula for blood pressure?

A

Systolic pressure/ diastolic pressure

40
Q

What is starlings law of the heart?

A

Same volume of blood that leaves will return

41
Q

What are the long term adaptations to heart as a result of exercise?

A

Increase MHR due to hypertrophy
Bradycardia
Increase in SV
Increase in blood supply to myocardium, making heart more efficient

42
Q

What are the long term adaptations to the vascular system as a result of exercise?

A

Greater tolerance to blood lactate levels
Increase in blood volume and haemoglobin count
Improved capillarisation around lung alveoli
Therefore increase in VO2 max
Greater elasticity of blood vessels
Basically oxygenated blood is able to reach the body’s extermeties easier, servicing limbs and reducing problems such as thrombosis, cardiac functioning more efficient.

43
Q

Describe the air pathway to describe how air is breathed in

A

Nasal cavity to pharynx to larynx to trachea to bronchi to bronchioles to respiratory bronchioles to alveolar ducts to alveoli

44
Q

What is the pulmonary pleura?

A

A self enclosed membrane covering the lungs, reducing friction between lung tissue and ribs

45
Q

What is total lung capacity?

A

Total volume of air in lungs following maximum inspiration

46
Q

What is vital capacity?

A

Maximum volume of air that can be forcibly expired following maximum inspiration

47
Q

What is tidal volume?

A

Volume of air inspired or expired per breath

48
Q

What is residual volume?

A

Volume of air remaining in lungs after maximum expiration

49
Q

What is minute ventilation?

A

Volume of air inspired or expired in a minute

50
Q

Describe short term changes to ventilation as a response to exercise

A

Anticipatory rise
Rap rise due to proprioceptor stimuli
Sub maximal exercise causes a level off
Maximal exercise causes a slower increase, producing lactic acid
Rapid decline as exercise ends due to cessation on stimuli
Much slower decrease later on as metabolites such as lactic acid are cleared

51
Q

Describe the respiratory control centre.

A

Two centres-
Inspiratory- basic rhythm of ventilation, sends impulses to diaphragm etc to control breathing.
Expiratory- active during forceful breathing, sends impulses to muscles of expiration

52
Q

Describe the chemical control of blood

A

Chemoreceptors respond to changes in CO2 in blood, sense constituents of blood as is flows by. These receptors send messages to inspiratory centre which stimulates respiratory muscles to alter breathing rates

53
Q

Describe how proprioceptors in joints and muscle influence breathing

A

They send signals to RCC about tension withing and state of contraction of a muscle, and hence when it is being used intensely and requires more oxygen

54
Q

What is hypoxia?

A

When at altitude, partial pressure of oxygen is less, so haemoglobin can’t carry as much oxygen, reducing ability to perform

55
Q

Describe the role of myoglobin

A

A substance that binds to molecular oxygen with a greater affinity than haemoglobin, taking oxygen across a cell to mitochondria so oxygen can be consumed

56
Q

What is arterio venous oxygen difference?

A

A difference in oxygen content between arterial and venous blood, due to absorption of oxygen from blood during maximal exercise

57
Q

What happens to the a-vo2 difference during exercise?

A

Is triples

58
Q

What is the long term effect of aerobic training on a-vo2 diff?

A

It increases it, so athletes can extract more oxygen from their blood

59
Q

What adaptations occur to the respiratory system as a result of exercise?

A

Diaphragm and intercostal muscles get stronger, more capable of working without cramps and stitches
Increased blood flow to upper lobes of lungs to increase utilisation of lung alveoli and hence increase vo2 max
Improved recovery from exercise, reduced oxygen debt
Big increase in breathing rate at maximal workloads