Cardiovascular System Flashcards by Jennifer Shin

Albumin

In plasma that transports fatty acids and steroids Regulate osmotic pressure of the blood facilitating transfer of substances across the capillary wall

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Plasma from which he clotting factor has been removed

Serum

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The percentage of volume by red blood cells

Hematocrit

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Granular leukocytes

What’s most abundant?

Function

Neutrophils, eosinophils, and basophils

Neutrophils

Instant defense, not very selective

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Agranulocytes

What’s most abundant

Function

Lymphocytes, monocytes, megakaryocytes

Lymphocytes after neutrophils. Lymphocytes can live on for years and years

More selective, long term defense

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What are platelets

Have nuclei? Or other organelles?

Process from loose plug to tight plug

What can they make?

Small portions of membrane-bound cytoplasm torn from megakaryocytes.

Prostaglandins

No nuclei but has mitochondria, actin/myosin, Golgi body and ER

Loose plug - platelets sticking to endothelium and to each other. Fibrinogen activated to fibrin to form threads to form a tight plug

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Plasma function

Blood pressure, immunity (antibodies and WBC), contains ions urea and proteins to replace tissues, organic and inorganic compounds, blood clotting

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How is the heart contraction set?

SA node from the right atrium that sets the pace. Auto rhythmic, it contracts by itself at regular intervals spreading to the surrounding via electrical synapses

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Is pace of the SA node faster than the heart beat?

Yes but the parasympathetic nerve inner hates the vagus nerve that slows down contractions to produce the typical resting heart rate

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Why is it important that the AV node is slower to depolarize?

So the atriums can squeeze their contents into the ventricle before the ventricles can contract

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Bundle of His

Between the heart

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Purkinje fibers

Conductive fibers hat branch out in the ventricular walls

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Arteries

Walls of arteries
Type of muscle
Size of the arteries vs. smooth muscle ratio

Thick and very elastic
Thick smooth muscle surround it typically innervated by the sympathetic nerves (ex. Epinephrine vasoconstricting smooth muscles)
Larger arteries have less smooth muscle, less affected by the nervous input

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Arterioles

Thermoregulation

Very small wrapped by smooth muscle
Construction dilation rapid under nervous and endocrine control
Bring warm blood to the surface to the skin to cool down; prevention would be construction of the arterioles

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Capillaries

Wall composition
Muscle?

Microscopic blood vessels
Huge surface area by branching of larger structures
Walls made of endothelium (only one cell thick) and has pinocytotic vesicles
Nutrient and gas exchange
Heat exchange
No muscle

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Methods by which materials cross capillary wall

Fenestration
Pinocytosis
Diffusion
Moving through space between the cells

Method depends on size, and polarity

Veins

Wall composition

Volume storage 
Wall much thinner 
Less elastic, less muscle 
Holds the most blood 
Slow flow 
Largest diameter

Systolic vs. diastolic pressure

Highest vs. lowest pressure

Contraction of the ventricle vs relaxation of the ventricles and filling of the atria

Relationship between pressure, flow, and resistance

Flow is linearly proportional to pressure difference and inversely linearly proportional to resistance

Blood pressure that must be maintained in the arteries

100 mmHg

Low, it would be insufficient for blood to go back to the heart and transfer of nutrients across the capillary walls

Baroreceptor reflec

Mechanism

Quick nervous input

Mechoreceptors

Change the output of the blood from the heart by signaling the SNS and PNS.

Can change the total peripheral resistance by constricting or dilating the arterioles which have the most resistance

Renin-angiotensin-aldosterone

Mechanism

Slow hormonal control.

Mechano receptors in arteries detecting blood pressure.

Change the output of the blood from the heart through regulation of plasma volume.

Can change the total peripheral resistance through constriction or dilation of smooth muscles surrounding arterioles (arterioles provide the most resistance).

Resistance vs. cross section

How come capillaries are not the most resistance?

Inverse. Larger diameter least resistance

They are parallel

Blood velocity vs. cross sectional area

Is blood flow rate constant?

Inverse. So movement is slowest in the capillaries with the largest cross sectional area.

Blood flow rate is approximately constant

Flow of a real fluid

R^4 (very radius dependent) Pressure difference Inverse to length Small radii of individual capillaries rather than the total cross sectional area so flow is slowest in the capillaries

Blood velocity vs. capillaries

Total cross section of the capillaries. Largest so velocity is the slowest. Not the same as flow rate.

Velocity of the blood vs. pressure is inverse. Does that mean the pressure is highest in the capillaries?

No, because blood is not an ideal fluid. Energy is not conserved bc of friction In fact, the pressure is very low in the capillaries.

Osmotic pressure vs. hydrostatic pressure on the capillaries

Flow of fluid from the tissue into the capillaries Because the blood is moving so slowly, it exerts a high pressure on the wall of the capillaries so out of the capillary and into the interstitium. Hydrostatic pressure is greater than osmotic pressure at the Venule end of the capillary. So net flow is into the capillary.

Net result of fluid exchange by the capillaries

10% fluid loss from the capillaries to the interstitium, to the lymph

How does the heart initiate the contraction?

SA node from the right atrium It sets its own pace and starts the contraction It contracts by itself at regular intervals and spread its contraction by electrical synapses (gap junctions)

Blood velocity

Total cross sectional area

Rate of blood flow

Differential pressure Radius^4 Length: longer slower

Change in hydrostatic pressure across the circulatory system

Goes down Pressure causing hints to go into interstitium

Change in osmotic pressure

Stays the same Pulling pressure from the dilutes causing the flow of fluid from tissues into capillaries

How does the pressure of osmosis change?

It remains constant

How much fluid is lost to the lymphatic system?

10%

Systole

Higher blood pressure; contraction of the ventricle

Diastole

Relaxation of the atria; lower blood pressure