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mcdb1b > circulatory system > Flashcards

circulatory system Flashcards

1
Q

Circulatory Systems: functions

A

Transporting
Thermoregulation
Communication between cells and organs
Communication between individuals

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2
Q

Circulatory Systems: functions
Transporting

A

Transporting things around the body
Nutrients
Waste
Gases
Metabolic products
Things that need to be regulated

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3
Q

Thermoregulation

A

Conserve heat or generate heat

Heat can be redistributed to different parts of an organism by constricting or dilating vessels
Smooth muscle is key to regulating this
Constricting or dilating vessels

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4
Q

Communication between cells and organs

A

Signaling Via hormones

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5
Q

Communication between individuals

A

Think of blushing

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6
Q

Why do we need a circulatory system

A

Bigger organisms need to ensure cells deep in the body get an adequate supply of oxygen, nutrient and so on, and that wastes don’t build up
Lot of calories stored through glycogen need to be distributed

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7
Q

Two types of circulatory systems

A

Open circulatory system -> arthropods and non-vertebrates

Closed circulatory system

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8
Q

Open circulatory system

A

Pulls in hemolymph and dumps it back into empty space
Interstitial fluid is being brought into heart and squished back out
Heart moves extracellular fluid through vessels
Fluid (hemolymph) leaves vessels and filters through tissues as interstitial fluid
The fluid in the circulatory system and the interstitial fluid are essentially the same
Fluid returns to the heart through the pores called ostia
Valves ensure directional flow

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9
Q

Closed circulatory system

A

Have distinct blood compartment that is distinct from interstitial fluid
Blood is separated from interstitial fluid
Exchange occurs with interstitial fluid at capillaries
Blood is pumped through vascular systems
One or more hearts
Flow of blood regulated by varying diameter of vessels
Specialized blood cells

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10
Q

In a single circulation, like with a fish, blood leaving the heart goes to

A

closed circulatory system
the gills
Blood is propelled through the artery via atrium and ventricle and bring it to the gills where there is an exchange of gasses that are dissolved in the water
CO2 is excreted and oxygen is gathered at gill capillaries
Blood goes back into the artery and to the body capillaries
Where oxygenated blood is distributed

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11
Q

Amphibians circulatory system -> frog

A

Blood leaves central ventricle and instead passing through lung and skin it re-enters the heart and gets pumped around again
Don’t have two capillaries in a row it is separated into two systems
Gills increase surface area for gas exchange
Oxygenated and deoxygenated blood kind of mix together
one ventricle where oxygenated and deoxygenated blood can interact

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12
Q

Human/mammalian circulatory system

A

have Two complete circulatory systems

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13
Q

what do the blue veins indicate

A
  • deoxygenated blood
  • Blood that is returning from various parts of your body that have been depleted of oxygen for oxidative phosphorylation
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14
Q

how does the circulatory system work for mammals

A
  • Enter the right side of the heart in the chamber called atrium
  • Goes into a ventricle
  • Leaves the right ventricle and splits left and right
  • Right Half goes to the left lung, gets oxygenated and returns to the left side of the heart entering another atrium into a ventricle and out the ventricle into a big artery called the aorta and back to give blood to the upper and lower body
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15
Q

human heart composition

A

Contain 4 chambers
2 atria and 2 ventricles

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16
Q

Atria

A

chambers that fill up with returning(venus) blood; hold it and contract a little bit and send blood into the ventricle

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17
Q

Ventricles - right and left

A

Right ventricle pumps blood through the pulmonary circuit → lungs
Goes to lungs and comes back

Left Ventricle pumps blood through the systemic circuit
Through the aorta
Sends blood to your entire body

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18
Q

what do ventricles do

A

pump blood

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19
Q

why is the left ventricle’s walls thicker

A

more pressure required to pump more blood through systemic circuit

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20
Q

What is generating the force that pushes the blood through your body?

A

The contraction of muscle cells in your heart
Pumping of heart muscle

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21
Q

what heart valves exist

A

Atrioventricular valves

Pulmonary valve and aortic valves (semilunar)

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22
Q

Atrioventricular valves

A

Between atria and ventricles prevent backflow when ventricles contract
Blood enters into atria through big veins then into the ventricle then out of the ventricle through the pulmonary artery and to your lungs
Valves ensure that during this process blood flows in one direction only
Close up to prevent backflow from ventricles to atrium
Right - tricuspid
Cusp is how many flaps it has
Left - bicuspid

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23
Q

Pulmonary valve and aortic valves (semilunar)

A

Between ventricles and major arteries
Prevent backflow (into the ventricles from the arterial system) when ventricles relax
Tricuspid

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24
Q

Valves ensure blood flows through the heart in one direction only

which direction is this

A

Out the heart
Flow of blood goes from high pressure to low pressure
Pressure is the Squeezing of blood that the heart creates

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25
Q

AV valve closes just as

A

pulmonary valve opens\

Want to push blood to pulmonary and out the atrium

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26
Q

the cardiac cycle contains what two phases

A

Diastole
Systole

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27
Q

Diastole

A

Period of Relaxation
Both sides of heart are doing the same thing at the same time

Neither heart chamber is contracting

Blood coming in from the veins

Because the pressure of venous blood is higher coming into atrium than in the ventricles, the blood trickles down (pressure difference)

Blood returning to the heart from the veins passively fills the heart chambers

Both AV valves open
Atria are not contracting
Aortic and pulmonary valves closed

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28
Q

Systole

A

Contraction starts

Want orderly contraction
Two atria contract and two valves contract

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29
Q

when, in systole, do the atria contract

A

they contract first during atrial systole

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30
Q

atrial systole

A

Forces blood into the ventricles
Creates pressure
preceeded by both AV valves opening

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31
Q

when both the av vales are open what is going on iwth the other valves

A

Aortic and pulmonary valves are closed

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32
Q

what comes after the atrial systole

A

ventriculat systole

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33
Q

ventricular systole

A

The the ventricles contract
This forces blood out of the heart and into aorta and pulmonary artery
Walls contracting, squeezing of the blood and AV valves close (when AV valve closes volume of blood iin left ventricle flattens(no blood in or out))
Aortic and pulmonary valves open

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34
Q

what happens when Aortic and pulmonary valves open

A

Pressure in ventricle is higher than pressure in aorta

this causes valves to open and blood to leave

Drops volume of blood in ventricle bc blood is moving to arteries

When pressure in ventricle drops below aortic pressure, aortic valve has to close
Prevents backflow of blood from aorta to ventricle

Blood leaves heart into arteries

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35
Q

Elastic pressure of arteries: why do you want to maintain pressure in arteries

A

Continuous flow
Caused by continuous pressure

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36
Q

T or F ; There is a period during left ventricular systole when both the left AV valve and the aortic valve are closed

A

True
Av valves close

Aortic valve opens when there is enough pressure in aorta

Before that period both are closed

Aortic valve doesn’t open until pressure gets higher than the pressure in the aorta

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37
Q

Effective pumping requires:

A

sequential contraction of chambers (atria contracting and then ventricles)

Coordinated contraction of muscle cells within each chamber

Cardiac muscles have action potentials just like skeletal muscles

Cardiac muscle cells are joined together by gap junctions

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38
Q

why is it important that Cardiac muscle cells are joined together by gap junctions

A

When you depolarize, the wave of action potential moves along the heart and they all contract together
The flow of current (Na+) between cardiac cells is key to the sequential and coordinated contraction of the heart

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39
Q

how do cardiac muscle cells compare to skeletal muscle cells

A

Cells are smaller than skeletal muscle cells

Cardiac muscle cells branch and interdigitate: can withstand high pressures

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40
Q

cardiac Muscle cells are joined together by something called ___

A

intercalated discs
-make up junctions

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41
Q

intercalated discs

A

These are junctions between muscle cells
Gap junctions

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42
Q

Gap junctions

A

Pores which small molecules can move through
Cardiac and smooth cells are arranged in sheets
Cells in the sheet are in electrical contact via gap junctions
An action potential in one cell can spread to all others in the sheet
Synchronize contractions
Why action potentials can spread from one cell to next(depolarizes one then next and next)

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43
Q

give a summary of where the wave of depolarization moves

A

A wave of depolarization, setting off contraction, sweeps across the heart from the SA node, then across the atria. It pauses at av node and then spreads across the ventricles

44
Q

SA node(pacemaker) (sinoatrial)

A

Muscle cells that initiate their own action potentials (about 70 times a minute)
Initiates at pacemaker
Atrial muscle is linked by gap junctions so a spread of depolarization is observed through the atria and the muscle cells quickly contract as one
Squeeze extra blood into ventricles

45
Q

Depolarization signal needs to travel through atria and get to ventricles
Place where the two chambers are connected →

A

AV node

46
Q

Av node doesn’t conduct very fast
Delay occurs
why

A

Want atria to finish contracting before we get the ventricles contracting

The delay ensures that the atria are empty before the ventricles contract. This prevents the ventricles from contracting too early.

47
Q

once the depolarization wave is through the av node where does it go

A

there are bundles of muscle cells that conduct the depolarization much faster than others
They lie at the heart apex (bottom of heart)
Set off depolarization up the heart
Squeezes blood up
Purkinje fibers

48
Q

Electrocardiogram (ECG or EKG)
During the cardiac cycle there are so many cardiac muscle cells depolarizing and repolarizing in unison that you can pick up an electrical signal at the skin
Peaks of EKG correspond to specific events in the cardiac cycle

describe the peaks

A

first small bump = P-wave
- atria contracting
-atria depolarizing

Then the relaxing is the AV node delay
- Q

The deflecting downwards is the spreading through the heart
- Q

The big spike = ventricular depolairzation (QRS_)
- R

going even further below starting level
- S

last bump
- repolarizarion of the ventricles
- T

49
Q

Abnormal ecg (partial heart block)

A

P wave happening at nice spaced intervals
Atral contractions
Atrial contractions should leave to ventricular contractions
Not happening →

irregular QRS that become partially de-linked

50
Q

Atrial fibrillation

A

Atria are not contracting in coordination
Not beating together so there isn’t a distinct peak
Not clean intervals and don’t have clean p waves

51
Q

Tachycardia

A

Abnormally fast heart rate

52
Q

Ventricular fibrillation

A

Ventricles aren’t contracting together
Out of sync
Electrical shock

53
Q

Atrial fibrillation isn’t so bad - why?

A

A lot of ventricular filling happens even before the atria contract
You could get by without atria not contracting

^^ leaky filling of ventricles

54
Q

SA node cell composition

A

These cells have an additional ion channel

55
Q

Slow influx prepotential

A

SA node ion channel opens up when it is polarized and lets sodium ions in

Brings itself to threshold

This then opens up voltage gated calcium channels
Depolarizes cell
Then action potential occurs(calcium bind with troponin and act with myosin and it repolarizes with potassium outflow

56
Q

Bby itself, SA node has rhythmic depolarizations at about 70/minute
The cell essentially brings itself to threshold by

A

the slow influx of Na+
Does not have a stable resting potential
Na+ channels open when you polarize and close when depolarize

57
Q

One of the major regulators is the autonomic nervous system

what type of nerves exits

A

Parasympathetic nerves and sympathetic nerves

58
Q

Parasympathetic nerves characteristics

A

Rest and digest
Heart beat relatively low
Not breathing heavily
Digesting food
Slower depolarization

59
Q

Sympathetic nerves

A

Fight or flight
Stressful
Intense exercises
Emotionally and physically stressful
Adrenaline rush
Increase heart rate
Ship blood to necessary areas
Faster depolarization

60
Q

One of the main things we can change to change heart rate is

A

Depolarization potential
Sodium influx prepotential

61
Q

Sodium influx prepotential

A

a gradual influx of sodium ions into a cell that occurs when there is no resting potential. This prepotential leads to the cell reaching threshold, which initiates a rapid depolarization and contraction

62
Q

how do we change the heart rate with action potentials

A

change number of action potentials –> more is faster and less is slower

63
Q

Beta blockers

A

Slow down the heart rate
Used to treat high blood pressure
Block the activity of the sympathetic branch

64
Q

Caffeine
Works by

A

increasing the rates of depolarizations at the SA node

65
Q

Nicotine

A

Stimulates the activity of the sympathetic neurons that deliver impulses to the heart

66
Q

Vessel structure

what vesseles exist

A

arteries
arterioles
capillaries
venules
veins

67
Q

Arteries - summary

A

Large vessels that carry blood away from heart
Aorta and pulmonary arteries

68
Q

Capillaries- summary

A

Exchange between blood and interstitial fluids
Bring nutreitns and oxygen to cells

69
Q

Arterioles- summary

A

Control distribution to capillary beds by adjusting state of constriction or dilation
Regulates where blood goes

70
Q

Venules- summary

A

Blood from capillaries go here
Smaller vessels
Leaving capillary beds and goes to veins

71
Q

Veins- summary

A

Return blood to heart

72
Q

The structure of vessels through the circulatory system
All vessels are lined with

A

endothelium

73
Q

endothelium

A

The surface that the blood touches inside the tubes
Made up of endothelial cells
Type of epithelial cells

Purpose is to make tight, sealed surface that keeps the contents of blood inside

74
Q

In capillaries are where there is a slightly different property of the endothelium where it becomes

A

leaky
Where exchange occurs

75
Q

describe composition of artery

A

Endothelium surrounded by elastin layer then smooth muscle - elastin again - and connective tissue
Connective tissue gives it strength
Resistive outward pressure
And smooth muscle

Elastin
Give vessel strength and elasticity

76
Q

Vessel adaptations: arteries

A

Big vessels leaving the heart
Highest pressure in the whole system is herre
Need to be tough
Endothelial cells line the inside of the vessel

In the arteries and arterioles the endothelial cells are tightly bound together to prevent leakage

77
Q

Elastin

A

Give vessel strength and elasticity
Support high blood pressure
Stretching to conserve energy from contraction
Recoil during diastole(heart relaxation) push blood forward

78
Q

Pressure maintained in arteries because

A

it is elastic like a balloon
When ventricle is relaxed the artery recoils which keeps the blood flowing
Pressure reservoir
Blood flows continuously, not just while heart is contracting

79
Q

Veins purpose

A

Return blood to heart

80
Q

the pressure in veins is low

the pressure isnt enough to send blood back to heart

Blood tends to accumulate in veins (especially at lower extremities)

how does body move blood up

A

One-way flow in veins help
Also skeletal muscle contraction helps move the blood

81
Q

blood in veins when you are at rest vs when you are exercising

A

When youre relaxed, the volume of blood in your veins is higher than when you are exercising
Veins pass through muscle and when you exercise you create pressure on the veins that pass through that muscle and that squeezes the veins
When you need actively flowing blood veins are squeezedd and that pushes blood towards heart
Get more actively circulating blood

82
Q

Varicose veins/failed veins

A

Blood pools in veins because blood doesn’t go back to heart

83
Q

Blood coming from heart go to arteries and into smaller vessels called

A

arterioles

84
Q

There are lots of smooth muscles in arterials
Involuntary muscle
We can squeeze smooth muscles and narrow that vessel

the blood then branches off into

A

capillaries

85
Q

what regulate blood flow to specific capillary beds

A

Smooth muscle cuffs - “precapillary sphincters”

These smooth muscles are targets of autonomic nervous system and hormones

86
Q

Autoregulation of arteriole diameter depends on

A

local environment

87
Q

Autoregulation

A

Where the capillary beds and arterials are flowing through the tissues that’s using the oxygen and so on

Arterials are keeping track of what is happening in the local environment

88
Q

what causes local dilation

A

High CO2
Low O2
Byproducts of cellular metabolism
Lactic acid and low pH
Locally produced factors like histamine and NO cause local vasodilation

89
Q

Tightening hand what is happening?

A

Not getting enough oxygen
Not removing waste
Builds up CO2 and lactic acid
Local control

90
Q

In a capillary
Some substances can diffuse directly across the endothelial cells
like_____–

other moleules like _— move between cells via gaps between endothelial cells

A

O2 and CO2

glucose and water soluble substances

91
Q

size of clefts

what can and cant get through

A

These clefts are small enough that the blood cells and large proteins are retained in the capillary

92
Q

Some large proteins are selectively endocytosed and exocytosed by endothelial cells

for example

A

Peptide hormones

93
Q

Pressure on circulatory system comes from the heart
explain how
explain how this pressure changes throughout the circulatory system

A

Heart squeezes on blood, creates kinetic energy and the blood rushes out of the heart with high pressure

Friction of blood against walls slows it down
Pressure becomes very low in circulatory system
Need skeletal muscle pump to move blood back

94
Q

how is capillaries part of the reason blood slows down

A

Even though capillaries are the smallest vessels there are so many of them that their total cross sectional area is greater than any other vessels

The big area and slow flow encourages exchange between capillaries and the interstitial fluid

Then the pressure drops throughout the system, biggest drop being in the arterioles

The pressure drops from the start to end because the endothelial cells in the capillaries are leaky → movement of water out the capillaries

95
Q

Two forces to consider concerning movement of fluid(water) between capillary lumen and interstitial fluid:

A

Blood pressure

Osmotic pressure

96
Q

Osmotic pressure

A

There will be a net movement of water from an area of lower solutes to higher solutes
More solutes in capillary lumen so move water into capillary

97
Q

When these two opposing forces are taken into consideration, there is a net movement of water____-
why

A

out of the capillaries
Pressure in capillaries is high
Pressure in interstitial fluid is low
Fluid comes out from capillaries(water) to interstitial fluid
Blood pressure drops along capillary

98
Q

Lymphatic system

A

Series of vessels that surround capillaries

Where we get water back into circulatory system
Water moving out of the capillaries into the interstitial fluid needs to get back into the circulatory system
Water is taken up b the lymphatic system
Low pressure vascular system that moves fluid back to the circulatory system

99
Q

Q: elephantiasis is a disease caused by a parasitic worm. Which of these is the likely underlying problem

q. Low blood pressure leads to too little water leaving the capillaries
b. The lymphatic capillaries are taking up too much fluid
c. The osmolarity of the blood/plasma is higher than the interstitial fluid
d. Blood pressure is too low
e. The lymph vessels are blocked

A

(e)The lymph vessels are blocked

100
Q

Systolic vs diastolic pressure
The pressure is created by

A

he squeezing and ejection of the blood by the heart ventricles

101
Q

Arterial pressure is most important because it is

A

driving blood into the arterioles and capillaries

102
Q

Proper blood pressure ensures that blood continues to flow through the system (120-129/80-84)
too low causes ___

too hhigh causes +____

A

Too low and tissues don’t get enough blood flow (less than 90/60)
-Heart damage, blood loss, dehydration

Too high (above 140/90)
Leads to coronary artery disease, stroke, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, chronic kidney disease
Causes: obesity, genetic factors, drug use
Too much fluid at once → pressure is too high

103
Q

We are constantly doing things that could disrupt our blood presssure
like

A

Drinking (increasing blood volume)
standing/sitting down
Sweating (decreasing blood volume)
Stress (increased heart rate)
Exercising

104
Q

how does exercising disrupt our blood pressure

A

Heart rate goes up
Blood flow to muscles go up
Mean arterial blood pressure goes up only a little bit
Diastolic pressure doesnt change (at resst so lollll)
Cardiac output increases (pumping more blood)
Systolic pressure increases

105
Q

Relationship between vasoconstriction/vasodilation and blood pressure

A

Dilated vs constricted vessel
Smooth muscle is causing it
Same amount of blood going through both, contrsitced is gonna have higher pressure

106
Q

Total peripheral resistance

A

Sum of all vascular resistances within systemic circulation
Whats gonna impede the flow of blood through everything -> resistance
Arteries supply tissues and organs in parallel circuits
Changes in resistance in these circuits determines relative blood flow

107
Q

If all your body did in response to exercise was to increase blood flow to muscles there would be_____

A

a drop in blood pressure throughout the circulatory system

Vasoconstriction to counter the muscle vasodilation helps to maintain blood pressure
Increased heart beat also helps to maintain blood pressure

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