The Heart Flashcards

1
Q

What are the 4 main functions of the CV system?

A
  1. Transport o2, nutrients, and metabolites to tissue
  2. Remove waste
  3. Distribute and secrete hormones
  4. Involvement in Homeostatic mechanisms
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2
Q

Equation for resistance?

A

1/r^4

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3
Q

Equation for flow?

A

Pressure difference / Resistance

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4
Q

How is flow created and what is this called?

A

Pressure difference between two points = Driving pressure

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5
Q

How is flow created in the heart?

A

Ventricular contractions causes a pressure difference between chambers, this pressure is passed into the blood causing it to flow along the blood vessels down a pressure gradient

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6
Q

Equation for velocity of flow?

A

Flow rate/Cross sectional area

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7
Q

What are the key landmarks in the Thoracic Cavity?(6)

A

Thyroid gland
Lung
Trachea
First rib
Diaphragm
Apex of the Heart

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8
Q

What is the heart surrounded by? And what is its structure?

A

A fibrous sac called the Pericardium

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9
Q

What are the 2 roles of the Pericardium?

A
  1. Protects the heart by providing lubrication to allow constant movement
  2. Anchors the heart against the diaphragm and spine
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10
Q

What are the valves of the heart?(5)

A

Pulmonary valves
Aortic Valves
Coronary arteries
Tricuspid valve
Mitral valve

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11
Q

What are the key landmarks in the heart?(9)

A

Vena cava
Inferior vena cava
Right atrium
Right ventricle
Pulmonary arteries
Pulmonary veins
Left atrium
Left ventricle
Aorta

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12
Q

Compare the properties of cardiac muscle and skeletal muscle? (Muscle fibres, Action, Sarcoplasmic reticulum, Nuclei, Source of Ca2+, Metabolism and energy)

A

Both have striated fibres
Cardiac is involuntary using the ANS
Cardiac has a less and smaller SR
Cardiac has a single nucleus per cell and centrally located compared to multiple and peripherally
Cardiac has SR and Ca2+ entry Skeletal only has SR
Cardiac is highly oxidative compared to oxidative and glycolytic

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13
Q

What is the excitation-contraction process in cardiac muscles?

A
  1. Sodium enters the intracellular fluid
  2. Calcium also enters via the L type Ca2+ channel
  3. This triggers more Ca2+ to enter from the Sarcoplasmic reticulum through Ryanodine receptor channels
  4. Thin filament are activatied
  5. Cross bridge cycling, force generation, and filament sliding theory
  6. Ca2+ ATPase pump - ADP > ATP
  7. Potassium leaves and enters T-tubule lumen
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14
Q

Where is smooth muscle located?

A

In organs

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15
Q

Structure/Properties of smooth muscle?

A

No sarcomere, the actin an myosin filaments are arranged in a lattice around a cell

They attach to cells via specialised areas - dense oldies

Mechanically connected to neighbouring bodies by dense bands

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16
Q

What is the anatomy of arteries?

A

Adventitia
Elastin
Endothelium
Smooth muscle
Pre capillary sphincters

17
Q

Function of arterioles?

A

Altering levels of resistance to blood flow in order to distribute the available amount of blood to where it is needed

18
Q

Capillary adaptations?

A

Large SA
Thin = quick diffusion
Spread across the whole body

19
Q

Veins compared to arteries?

A

Larger
Valves
Less elastic
Thinner
Less smooth muscle

20
Q

Definition for Cardiac Output?

A

Volume of blood pumped out of the heart every minute

21
Q

Equation for Cardiac Output?

A

Heart rate x Stroke volume

22
Q

Typical values for Q, HR, SV? (Untrained rest, Untrained , Trained and Elite - during exercise)

A

Q - 5.6, 20, 23, 30
HR - 70, 192, 190, 178
SV - 80, 105, 120, 170

23
Q

How is HR decreased?

A

Decrease = Parasympathetic nerve endings - vagus nerves secrete acetylcholine
= SA node stimulation
= Membrane becomes more hyperpolarised
= depolarising drift is slower
= slower rhythm
= HR decreases

24
Q

How is HR Increased?

A

Increase = Sympathetic fibres - Cardiac nerves release norepinephrine, alongside circulating epinephrine
= SA node stimulated
= membrane to become more polarised
= depolarising drift is faster
= faster rhythm
= Increase HR

25
Q

What regulates SV?

A

1) Force at which cells contract which is regulated by
- length tension properties of cardiac muscle cells
- hormonal influence on contractility
2) Arterial pressure against which they have to eject blood

26
Q

Starling’s Law of the Heart?

A

End-diastolic volume can be increased by greater venous return which causes greater stroke volume due to greater stretch on cardiac muscle fibres = increase force of contraction

27
Q

Mean Arterial pressure equation? (2)

A

Diastolic + (systolic-diastolic / 3)

Cardiac output x Total peripheral resistance

28
Q

Factors affecting Blood pressure?

A

Age - loss of elasticity
Higher in foot than head - due to hydrostatic pressure
Gender - Women have lower on average

29
Q

What is Dalton’s Law / Partial Pressure?

A

The pressure of a gas mixture is equal to the sum of the pressures of the individual gases.

30
Q

What affects the Rae of diffusion?

A

Surface Area
Thickness of barrier
Partial pressure difference
Solubility of gas

31
Q

Fick’s law of diffusion?

A

The rate of diffusion is proportional to the surface area and concentration difference

32
Q

What is the structure and function of haemoglobin?

A

Oxygen binding protein within red blood cells. ]Each molecule contains 4 polypeptide chains and 4 haeme groups, in each haeme group is a ferrous atom (Fe2+) that binds to a molecule of O2

33
Q

What does a left shift in oxyhemoglobin association curve mean?

A

Quicker loading and slower off loading

34
Q

What affects the oxyhemoglobin association curve ?

A

Acidity
23DPG
CO2
Temperature

35
Q

Describe CO2 carriage in blood?

A

CO2 is a lot more soluble than oxygen and dissolved CO2 plays an important role in its carriage