Cardiovascular System Flashcards
Albumin
In plasma that transports fatty acids and steroids Regulate osmotic pressure of the blood facilitating transfer of substances across the capillary wall
Plasma from which he clotting factor has been removed
Serum
The percentage of volume by red blood cells
Hematocrit
Granular leukocytes
What’s most abundant?
Function
Neutrophils, eosinophils, and basophils
Neutrophils
Instant defense, not very selective
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
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
Plasma function
Blood pressure, immunity (antibodies and WBC), contains ions urea and proteins to replace tissues, organic and inorganic compounds, blood clotting
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
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
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
Bundle of His
Between the heart
Purkinje fibers
Conductive fibers hat branch out in the ventricular walls
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
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
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
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
