The circulatory system Flashcards

1
Q

Describe the circulatory system of a unicellular organism

A

Simple diffusion
Convection
Steep conc gradient for nutrient/waste exchange

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2
Q

What is the primary function of the circulation system?

A

Distribution of gases/molecules
(nutrition, growth and repair)

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3
Q

What are the secondary functions of the circulation system?

A

Fast chemical signalling
Dissipation of heat
Mediates inflammatory and host defences to microbes

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4
Q

What regulation is required in order to change circulatory demands?

A

Body position/inthoracic pressure
Rest (deceleration of hr)
Emotional stress
Digestion
Sleep/wake

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5
Q

What are the 3 main components of the circ system?

A
  1. Pump (heart)
  2. Fluid (blood)
  3. Containers (blood vessels)
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6
Q

Pathway of blood around the body (from left heart)

A

Left atrium -> left ventricle via mitral valve -> Aorta via aortic valve -> into various organ systems -> right atrium via vena cava -> right ventricle via tricuspid valve -> lungs via pulmonary artery -> left atrium via pulmonary vein

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7
Q

Which side of the heart carries oxygenated blood?

A

The left side

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8
Q

What type of circulation is used by the left heart?

A

Systemic circulation

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9
Q

What type of circulation is used by the right heart?

A

Pulmonary circulation

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10
Q

Function of arteries

A

Distribution system (high pressure system)

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11
Q

Function of microcirculation

A

Diffusion and filtration

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12
Q

Function of veins

A

Collection system (reservoir)

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13
Q

Size of first order arteriole and venule

A

30 um

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14
Q

Size of fourth order arteriole and venule

A

5 um

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15
Q

Size of capillary

A

3 um

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16
Q

Is the combined cross-sectional area of the daughter vessels larger or smaller than the parent?

17
Q

Describe the structure of a vascular wall

A
  1. Endothelial cells
  2. Elastic fibres
  3. Collagen fibres
  4. Vascular smooth muscle cells
18
Q

Describe the structure of blood vessel walls

A
  1. Intima (tunica interna)
  2. Media (tunica media)
  3. Adventitia (tunica externa)
19
Q

Structure of a capillary wall

A

Tunica intima which rests on the basement membrane

20
Q

Specialisation of elastic arteries

A

High compliance
Enable vessels to cope with peak ejection
Recoil forces blood to move even when ventricles are relaxed

21
Q

Specialisation of muscular arteries

A

Greater vasoconstriction/vasodilation
SMC arranged circumferentially
Vascular tone (efficient flow)

22
Q

Specialisation of arterioles

A

Smooth muscle enables blood flow to capillary networks
Terminal regions
Precapillary sphincters (regulate blood flow to capillaries)

23
Q

Specialisation of venules

A

Porous
Thin smooth muscle layer
Thin walls for expansion (reservoirs)

24
Q

Specialisation of venules

A

Porous
Thin smooth muscle layer
Thin walls for expansion (reservoirs)

25
Specialisation of veins
Elastic but distensible 'Store' blood Large veins have valves to prevent backflow
26
What can lead to varicose veins?
Defective and leaky valves in veins -> Blackflow
27
Functions of capillary exchange
Glomerular filtrate Skin temperature regulation Hormone delivery Platelet deliver
28
Structure of capillaries
Endothelial cells and basement membrane
29
What are the 3 groups of capillaries from most-least leaky
1. Continuous capillary 2. Fenestrated capillary 3. Sinusoidal (discontinuous) capillary
30
What is oncotic pressure a result of?
Serum proteins (albumin)
31
What is starling equation showing?
The fluid transfer across capillary walls due to a sum of hydrostatic and osmotic pressures
32
What happens to Pc as it travels across the length of a capillary? Why?
Pc (capillary hydrostatic pressure) decreases along the length so filtration becomes absorption Due to fluid filtration
33
Function of the lymphatic system
Drains excess interstitial fluid in all organs but the brain Maintenance of blood volume
34
What vein is lymph returned to CVS via?
Subclavian veins