Lecture Notes for Exam I Flashcards
Function of Circulatory System
Movement of blood and transport of a variety of materials (metabolic substance; ex: oxygen, glucose & waste)
Protection; transports WBC, antibodies, proteins, etc
Cleans up damages; damaged cells & vessels
Distributes heat
Regulation of the body via transportation of hormones
Transmit force = distribution of fluid
What are the 2 parts of the Circulatory System?
Cardio Vascular System
Lymphatic System
Where do the arteries carry blood?
Brings fluid to capillaries (away from the heart)
Function of arterioles
Brings fluid to capillaries
They are small blood vessels
They connect arteries to capillaries
Capillaries
Only area of exchange (everything else is used to transport fluids)
They have thin walls to minimize distance for diffusion;
Their total surface area = 8,000 square meters (2 acres), allowing for lots of exchange
Located next to cells
Venules
Brings fluid away from capillaries
They empty into the veins
Veins
Brings fluid away from capillaries to the heart
Name all the blood vessels
Arteries Arterioles Capillaries Venules Veins
Order of blood flow leaving the heart to the systemic circuit in; name just the blood vessels
Big Arteries -> Smaller Arteries -> Arterioles
-> Capillaries -> Venules -> Veins -> Heart
Flow Equation
Flow = Difference in Pressure / Resistance
Resistance is related to
Friction between fluid molecules and tube wall
Friction between layers of fluid = the Viscosity
Small diameters pipes have low or high resistance?
High resistance to flow because there is a small distance between the fluid and the surface (the fluid rubs up against the surface)
Large diameter pipes have low or high resistance?
Less of a resistance to flow because they have a greater distance between the fluid and the surface
If you increase the viscosity of a fluid, what will happen to the flow?
Increase viscosity, increases resistance to flow
If you decrease the viscosity of a fluid, what will happen to the flow?
Decrease viscosity, decreases resistance to flow
Resistance Equation
R = (viscosity)(length of pipe) / (radius of pipe)^4
Basic Parts of the Lymphatic System
Lymph = primary fluid
Lympathic vessels = return fluid lost at capillaries to the cardiovascular system
Lymph nodes = they cleanse the lymph as it passes through them
Layers of the Heart Wall
Epicardium
Myocardium
Endocardium
Epicardium
Connective tissue on the outside layer
Thick and fiberous
Forms the pericardial sac (around the heart)
Myocardium
Middle Layer of the Heart
Big, thick muscle tissue
Squeeze the chambers of the heart when they contract
Composed mainly of cardiac muscle and forms the bulk of the heart
The Contracting Layer
Endocardium
Inner layer; “Inside the heart”
Thin, smooth, lubricated
Blood has to slide passed it
Continuous with the valves of the heart
Serous Membranes
Double layered membranes that secrete fluid in the inner margins, between two layers, making them slippery
2 sets of membranes are close together and are held together tightly by the water due to charge attraction
Visceral layer (Epicardium) -> adheres to organ
Parietal layer -> lines the wall of the cavity
Pericardium
serous membrane of the heart
True or False, the Heart is a single pump
False; the heart is a double pump because there are 2 circuits we can pump into
Pulmonary Circuit
Takes blood to and from the lungs
Pump for the pulmonary circuit is the Right Ventricle
Pulmonary capillaries in the lungs
Takes blood to and from the lungs?
Pump is the right ventricle?
Pulmonary Circuit
Right Ventricle is the pump for which circuit?
The Pulmonary Circuit
Systemic Circuit
Takes blood to and from everywhere else except the lungs
Systemic capillaries in other organs
Pump for the Systemic Circuit is the Left Ventricle
Takes blood to and from everywhere else except the lungs
Pump is the left ventricle
Systemic Circuit
The Left Ventricle is the pump for which circuit?
The Systemic Circuit
Which circuit the systemic or pulmonary has more resistance?
More resistance in the systemic circuit
In which circuit is arterial blood oxygen rich & venous blood oxygen poor?
The Systemic Circuit
In which circuit is the arterial blood oxygen poor & venous blood oxygen rich?
The Pulmonary Circuit
Why have the blood go back to the heart and not just straight to the systemic capillaries after receiving its oxygen?
If you have 2 pumps, each pump has to work half as much
Do not have to create as high a blood pressure to get you through the whole system
What is the function of the ventricles in the heart?
They are the pumps of the system
What is the function of the Atria?
Reservoir’s to collect blood while the pump (the ventricle) is contracting
Atria fills up with blood during ventricular systole
Acts like a supercharger in a car; it pressurizes the blood a little bit when it contracts so to better load the ventricle
Fills ventricle with more than it would w/o the atrial contraction
Systole
Ventricular Contraction
Term for Ventricular Contraction
Systole
Diastole
Ventricular Relaxation
Term for Ventricular Relaxation
Diastole
Which chambers have thicker muscle walls? Atria or Ventricles?
The Ventricles
Are the muscles of the Atria thick or thin?
Atria have to be distendable (able to widen) to collect blood so their muscles do not have to be thick
Is there more resistance in the pulmonary or the systemic circuit?
almost 3xs the resistance in the systemic circuit than in the pulmonary circuit
While at rest, what is the average volume of blood a person pumps
about 5 Liters of blood/minute
Which ventricle, the left or the right has thicker walls?
The left ventricle is much thicker than the right because it has to work about 3xs harder or generate 3xs the force of the right ventricle to overcome the resistance of the systemic circuit
What is the point of one-way valves?
Allow us to direct the flow of blood
Blood flows from high pressure to low pressure
Right ventricle sends blood to which side of the heart?
to the left side of the heart through the pulmonary artery, eventually branching into smaller and smaller arteries, eventually into arterioles, to pulmonary capillaries; blood in pulmonary capillaries drain into venules and then drain into pulmonary veins, pulmonary veins bring blood back to the left side of the heart to the left atria
Left ventricle sends blood to which side of the heart?
to the right side of the heart; the left ventricle pumps into the aorta, aorta branches into arteries, branching into smaller arteries, branch into arterioles, eventually will get to systemic capillaries, they will coalesce into venules, then into veins, then finally back to the biggest of the veins, the Vena Cava, which enters into the right atria
Atrioventricular Valves
Right valve = tricuspid valve
Left valve = bicuspid or mitral valve
when the ventricles become pressurized these flap valves shut off the atria
if you pressurize the atria, then the blood will flow through the valve into the ventricle
Right Atrioventricular Valve
Tricuspid Valve
Left Atrioventricular Valve
Bicuspid or Mitral Valve
Aortic & Pulmonary Semilunar Valves
when ventricles contract (pressurizes blood in the ventricle, high pressure), blood flows through the valve During diastole (when ventricular pressure falls), flap valves keep blood from coming back in
Purpose of the papillary muscles & chordae tendinae
Papillary Muscles = little bulges of ventricular muscle
Chordae Tendinae = “heart strings”, spring like chords
They connect the valve with the ventricular muscle
Keep the valve from closing to far due to the high blood pressure during contraction, inconvoluting
Coronary Artery
Brings blood from the systemic system to the heart, which branches into arterioles and capillaries which are embedded in the myocardial tissue
Drains into the coronary veins on surface of the heart; bring blood back to the vena cava
Purpose of Coronary Circulation
takes blood from the systemic circuit to the heart to feed the heart muscle tissues
the heart muscles cannot tolerate anaerobic metabolism, needs a constant supply of oxygen or they will die
every time your ventricles contract (during systole), that shuts off all the coronary blood flow to that muscle; therefore, the flow is intermittent, flow is during diastole
Systole in the Cardiac Cycle
ventricles are contracting, because the pressure is rising due to a decrease in volume
start of systole, ventricular pressure is less than atrial pressure
ventricles are filled with blood
pressure in ventricle becomes greater than atria so AV valves shut [“Lub sound”] & Semilunar valves open; blood ejects
“Lub” sound
the closing of the AV valves
2 Phases of Systole
Isovolumetric Contraction - the ventricular pressure is rising, ventricles are contracting, the volume isn’t changing, blood is not going anywhere yet, AV valve is shut preventing the blood from leaving
Ventricular Ejection - the pressure rises to a point greater than that of the arteries, the semilunar valves open and the blood leaves the ventricles into the artery
Diastole in the Cardiac Cycle
Ventricular relaxation, pressure plummets/falls
“Dub” sound = the closing of the semilunar valves
When the ventricular pressure becomes equal to or below the pressure of the arteries; the semilunar valves shut
Pressure continues to fall, to below the atrial pressure, so AV valves open and blood from atria enters the ventricle
2 Phases of Diastole
Isovolumetric relaxation - when the pressure in the ventricles are lower than atria, AV valves open and blood from the atria can enter
Ventricular filling - filling of the ventricles; the atria contracts to help filling of the blood
“Dub” sound
the closing of the semilunar valves; happens when the pressure inside the ventricles becomes equal to or below the pressure of the arteries
End Diastolic Volume
when the ventricles are as filled as they can be
the volume of the full ventricle which will then go into the system
about 80% of that volume comes before the atria contracts
End Systolic Volume
the volume of blood still left in the ventricle after full contraction
Cardiac Muscle
Striated
Contraction is controlled by Tropomyosin complex (need calcium)
Have electrical connections with their neighbors like smooth muscles
Adjacent muscle cells
Cells are held together by desmosomes
Gap junctions form electrical connections between the adjacent cells by connecting cytoplasm
The action potential in one cell can be conducted in another cell
Sinoatrial node
originated from sino venosus
the pacemaker of the heart
specialized cells derived from muscle cells but are not used for contraction, lost their contractile elements, just there for triggering action potentials
spontaneously depolarizes which is faster than the other tissues, which is why its the pacemaker
simultaneous contraction of atria
Atrialventricular node (AV node)
the delay node
slow conductor of action potential
the AV node is the only way a message can be conducted from the atria to the ventricle; nonconducting tissue lies between the atria and the ventricle
Atrioventricular Bundle
the conducting bundle after the AV node
sits in between the ventricles
aka the bundle of His
goes down the ventricle towards the apex and branches off into Purkinje Fibers after the apex
Purkinje Fibers
send a message up and into the ventricles
Summary of Electrical Pathway of Cardiac Action Potential
The pacemaker = the sinoatrial node (SA node); the fastest depolarization region
AV node is the only way to send the message from the atria to the ventricle; the delay node, slow conductor
Message eventually goes down the bundles, around the apex of the heart, to the Purkinje Fibers so areas within the ventricle receive that action potential, that triggers those cells to contract, and the message goes from cell to cell by gap junctions
Atria contracts and fills the ventricle before it contracts thanks to the AV node (the delay node)
Parasympathetic Nerves
Decreases heart rate
A branch of the vagus nerve coming out of the brain
Sympathetic Nerves
Increase heart rate
Come out of the spinal column
We can raise our heart rate by…
increase sympathetic input or lower parasympathetic influence
We can lower our heart rate by…
decrease sympathetic input or increase parasympathetic influence
Do the sympathetic or parasympathetic nerves influence the SA node at the same time or does only one influence at a time?
both influence the SA node
it’s like running the air conditioner and the heater at the same time in your house for a resulting temperature
Which of the nerves, sympathetic or parasympathetic influence the pacemaker the most at rest?
the parasympathetic have more of an influence/doing more work/working hard
so if you cut off both nerves, the heart rate increases
T or F, for cardiac cells summation of force is good
False
We do NOT want summation of force
Want the cells to have a very long absolute refractory period so they could not contract/will not respond to electrical events that come just after they were stimulated the first time
What causes the long plateau in action potential in cardiac cells?
Plateau caused by prolonged opening of the calcium channels
Calcium channels open during depolarization, so calcium permeability rises along with sodium permeability (not at the same rate) and causes the plateau in action potential/maintains depolarized state
Long plateau delays the repolarization so the sodium channels are unresponsive, they cannot conduct sodium ions through them, cannot conduct a second action potential until they get back down to resting potential
The sodium channels are staying closed longer
Events in the Cardiac Cycle (ECG or EKG)
P waves = atrial contractions, the depolarization of the atria
QRS waves = massive ventricular contraction, ventricular depolarization, atrial repolarized
T waves = ventricles repolarize
Equation for Cardiac Output
Cardiac Output = Stroke Volume x Heart Rate
mL/min) = (mL/beat) x (beats/min
Stroke Volume
the amount of blood that comes out of the ventricle when it contracts
SV = End Diastolic Volume - End Systolic Volume
Can adjust cardiac output by:
adjust the heart rate: change the sympathetic and parasympathetic inputs
adjust stroke volume: how much blood is ejected during each systole/contraction
How to change Stroke Volume
change either the end diastolic volume (fill with more blood) or the end systolic volume (squeeze more forcibly and wring out more blood)
Starling’s Law of the Heart
Relates to Intrinsic Control of Stroke Volume
Muscles of the heart contract more the more stretched they are
If more blood enters the ventricle while its relaxed during diastolic its going to contract more forcibly as a result b/c the walls are stretched more
How do we know the strength of contraction is proportional to the degree of stretching?
Relaxed cardiac muscles have a different filament arrangement then skeletal muscles; when the walls are stretched, the thick and thin filaments get more cross bridge formations
Extrinsic Control of Stroke Volume
Increase contractility of the heart
Contractility = the force actively generate for any given anatomical configuration of the sarcomeres/any given degree of stretching
We can get the heart to contract harder with the same amount of filling as before; this is what happens during exercise
Increased heart rate, so decreased amount of time for filling so you need to contract harder leaving less residual blood
Eject more blood per stroke during exercise; emptying the heart more completely, left with less residual blood
How do we get our heart to contract more forcibly?
Sympathetic activity on the heart MUSCLE, the ventricles mostly
Epinephrine (a hormone)
Sympathetic nerves allow a greater amount of calcium to enter the cell during each action potential, make the cell more permeable to calcium; more cross-bridges form
Digitalis
A drug that works on calcium ion channels
opens up calcium ion channels allowing the muscles to contract at a greater force
Type of ionophore
For people with weak heart muscles
Do large hearts = healthy?
Not always
An athlete has a big heart b/c large heart muscles
Weak hearts are big hearts b/c they are stretched; they are weak, thin, and distendable (able to widen)
The velocity of blood is inversely proportional to…
the total cross sectional area of that segment
What are you feeling when you take a pulse?
Each time the artery balloons out that represents a systolic episode of the heart, each time it goes down it represents a diastolic episode
Each stop further downstream we’re going to have a lower pressure
The pulse in the arteries is not quite as big as it was in the aorta; when we get down to the arterioles we may have somewhat of a pulse; no pulsating when we get to the capillaries or veins (which don’t pulsate)
Where is the largest drop in pressure?
The arterioles have the largest drop in pressure; lots of resistance**
How do we control where the blood flows?
Change the resistance in the pathways
Vasodilate – less resistance, leads blood to where you want it to go
Vasoconstrict - more resistance, less flow
In which pipes is the control of blood flow the best?
The arterioles
The smooth muscles of the arterioles are the ones that we vasoconstrict/dilate to effect the blood flow; its where you get the most bang for your buck
Atheroscelrosis
buildup of plaque in the coronary arteries, (asymptomatic) it doesn’t bother your blood flow, your heart gets enough oxygen, it works fine; can’t tell until its build up so much that the diameter of the fire hose has been decreased by plaque such that it becomes a major source of resistance in the circuit, its resistance is starting to match the resistance of the arterioles and capillaries downstream so on, then the flow is compromised
How can we get around a clogged or stopped artery?
A Shunt = a bypass or an alternative pathway to get around a clot
Anastomosis
a natural bypass
Common in the venous system
Absent in the arterial side of the circuit
Got a lot of anastomosis in the venous system to bypass the external forces; remember his example of people sitting cross legged in class, blocking off the venous return
Venaoclusion
Rarely prevents blood from going back to the heart b/c there are many paths
Arterialoclusion
can be devastating if it’s the wrong artery
artery that goes to brain = a stroke
artery that goes to heart = a heart attack
Flow is directed by altering the radius of which major vessel?
Flow is directed by altering the radius of arterioles
The arterioles are not elastic, don’t pulsate, but they do have smooth muscles around them so they can constrict or relax; you do not have to change the radius very much to effect the flow, flow is related to the radius to the 4th power,
Have local control of smooth muscle in arterioles
Local Control of the Smooth Muscle in the Arterioles
Smooth muscles of the arterioles are sensitive to the metabolism, in particular carbon dioxide or acid; the more carbon dioxide you add to the fluid the more hydrogen ions you make in that fluid and therefore the more acidic it becomes
Cells that are actively metabolizing produce carbon dioxide as a biproduct
The more metabolized the cells, the more carbon dioxide produced, the more acid produced, smooth muscles respond by relaxing so that you get a greater flow of blood in those areas which are working harder and producing the most carbon dioxide, they get more blood b/c they need more blood (oxygen, nutrients, take away more CO2)
Smooth muscles respond to an increase in carbon dioxide or acidity by dilating and allowing more blood flow into the area
Precapillary Sphincter
smooth muscles where capillaries branch off
surrounds the root of each true capillary and acts as a valve to regulate blood flow into the capillary
Sphincters open - blood flows through and takes part in exchanges
Sphincters closed - blood flows through the shunts and bypasses the tissue cells
Reflex Control of Smooth Muscles in Arterioles
Autonomic Nervous System
Overrides local controls with nervous reflex controls
ex: imagine running from a lion; you are going to want to shut off the blood flow to the gonads and gut because they just aren’t useful in this situation, and dilate the skeletal muscles; if it’s a long run the carbon dioxide is going to build up in the gut tissue and so on because there’s not a big blood flow going through there, you shut it down and sent it somewhere else, and that carbon dioxide builds up and is going to cause dilation of the arterioles, you don’t want that so you want to override it, send information to those arterioles saying constrict
Or on cold day; you conserve your body heat by constricting blood flow to ears and fingers, you sacrifice those areas
Adrenergic Sympathetic Fibers of Precapillary Sphincter
Norepinephrine is the neurotransmitter
Alpha receptors—when we increase the firing rate, you get vasoconstriction, contraction of smooth muscle
o In most arteriole smooth muscle in guts, viscera, gonads, etc.
Beta receptors in arterioles of the coronary circuit; circuit that feeds the heart
o Increase the firing rate = vasodilation
o Running from the lion, your heart rate is going up, its going to need more energy, more oxygen; want more blood to the heart muscle because it is working more
Cholinergic Sympathetic Fibers of Precapillary Sphincter
Acetylcholine is the neurotransmitter
In smooth muscles of arterioles that lead to skeletal muscles
Increase firing rate = vasodilation
When you are running from the lion, the arterioles leading to the skeletal muscles need to dilate to bring more blood to the muscles
Parasympathetic Fibers in Precapillary Sphincter
Neurotransmitter is acetylcholine
To a few arterioles (guts, genitals, etc)
Increase activity = vasodilation
Blood Flow at Rest vs Exercise
Increased heart rate & blood flow during exercise
Altered % of blood going to different parts:
• Brain—does not change between rest & exercise = constant
• Heart—250→750 = tripling of blood to the heart
• Skeletal muscles—10 fold increase; vasodilated all the circuits
• Blood flow to the skin increases to dissipate heat from the body to the environment
What to know about Veins
Low pressure
Veins offer very little resistance because they are so big
Veins are much more stretchable, blood goes in and distends the veous walls
Know as “volume control organs”
When pumping blood uphill, contract smooth muscle to keep vein from stretching; keep it tight
External Pressure Acting on Veins
Muscles act almost like a secondary pump and cause a pressure change
ALL veins have 1 way valves to prevent blood from flowing away from the heart and keep the flow towards the heart
Good Example when you breathe:
Inhalation-helps bring blood from abdomen, back to heart; helps venous return
Exhalation-pressure increase, pressure in the chest cavity is greater than that of the abdomen; one way valves prevent blood from being pushed back out towards the abdomen
Listening to Blood Pressure
During periods when artery blood pressure is greater than cuff pressure you will hear sound and it will get longer until it eventually will go away; the first time you hear the sound, that is your systolic blood pressure
Are flows always continuous in the body?
No
Law of Laplace
Tension is proportional to (Pressure X Diameter of the pipe, sphere, etc)
Tension is greater on bigger diameter if pressure is constant
• Ex: blowing up glove or inflating car tire vs a bicycle tire
As I increase the pressure, the diameter in the part with bigger surface area increases
Tension is greater in larger arteries than in smaller ones; because walls are extremely thick proportionally
Aneurism
Arteries balloon out Wall isn't strong enough to hold the tensile strength Gets weaker with time Blood will flow out randomly It's deadly
If we took a snapshot of the location of blood in the body it would show: (%)
84% in the systemic circuit (huge volume):
• 64% in systemic veins
• 15% in systemic arteries
• 5% in systemic capillaries
7% in heart
9% in pulmonary circuit
so if you give a pint of blood, your total blood volume will be reduced but the volume of blood in the arteries/heart/pulmonary circuit is not going to change; only the volume of the veins will change, they will become less engorged
Importance of Nitric Oxide (NO)
Gas
Vasodilator
Causes relaxation of smooth muscles, reduces muscle tension; Endothelial cells can produce NO which will then go into the muscle layer; NO activates an enzyme cyclic GMP to make the second messenger GMP; The second messenger then acts on other enzymes which causes relaxation of smooth muscle cells; Smooth muscle has calcium which binds to calmodulin complex, that then can act and cause the phosphorylation of the myosin head and we can get cross bridge formation; If you are able to slow down the phosphorylation side so that it cannot keep up with the dephosphorylation side then you are going to have a reduction in cross-bridge formation and a reduction in tension
Important Facts about the Capillaries
Single cell thick, long, thin, flat cells
Most have diameters just about equal to red blood cells
Major movement of materials from the blood inside the capillary to the fluid outside the cells, in the extracellular fluid, is by DIFFUSION
No capillary is very far away from a cell
Importance of blood flow in capillary exchange
As the cell metabolizes, carbon dioxide concentration is going to go up, and it will be higher than the carbon dioxide concentration in the interstitial fluid, so carbon dioxide will have a net diffusion out and that will increase the carbon dioxide concentration in the interstitial fluid, and it will then be greater than the carbon dioxide concentration in the blood plasma and it will then diffuse into the capillary
The blood moves so that increase in carbon dioxide that moves into the blood plasma will not just stay there and build up so the concentration will never become equal; new fresh blood will come in that has low carbon dioxide concentration
So carbon dioxide level in the plasma is always low b/c fresh blood is always coming in
Very important for replacing blood in order to main the carbon dioxide gradient (glucose gradient as well)
The more metabolizing you do the more blood flow you need to maintain gradient
Which solutes can cross the phospholipid bilayer of the capillaries?
Nonpolar solutes move right through the membrane
Oxygen, Carbon Dioxide, Lipids
Polar solutes cannot:
Sugars, amino acids, etc
Capillaries have margins where they are leaky (have gaps) so that polar materials can go through those gaps
The gaps are not tremendously big; proteins cannot go through, amino acids and simple sugars can go through these gap
Where are some of the more leaky capillaries located?
Find these in our kidneys (blood filters, want to take a lot of material from our blood) and also in the small intestine (absorb enormous volumes of solutes)
Capillaries in the liver are the most leaky
Are brain capillaries leaky?
No
Desmosomes forming tight junctions so the capillaries are not leaky
A lot more mediated transport in these capillaries
Pressure difference between the fluid inside the capillary and the fluid on the outside
Interstitial fluid is just like the plasma except it doesn’t have the plasma proteins
Osmotic concentration of the blood plasma is higher than the osmotic concentration of the interstitial fluid b/c of all the plasma proteins
Have higher concentration inside the capillary (blood plasma) than interstitial fluid
Fluid is going to move by osmosis from the interstitial fluid into the blood plasma (the capillary)
Ways material get out of the capillaries:
Diffusion (most this way)
Bulk Flow
What happens to blood pressure as you go from the arterial end of the capillaries to the venous end?
Blood pressure drops as you go from the arterial end of the capillaries to the venous end, but the osmotic concentration does not
Hydrostatic Force
physical force, higher in the capillaries than the interstitial fluid, capillary has blood pressure, pushing fluid out
Osmotic Force
fluid moves from areas of low osmotic concentration to areas of high osmotic concentration; force does not change from one end of the capillary to the other, pushing fluid back in
Which is the greater of the Hydrostatic Force and the Osmotic Force
Net loss of fluid at the arterial side of the capillaries
Regain fluid at the venal end of the capillaries
Typically you lose more fluid at the arterial end than you gain at the venal end
There is a net loss of plasma as it goes through the capillaries
What happens to your fluids when you are exercising?
Blood pressure increases because you have more flow
Osmotic pressure is the SAME
The blood that enters will be at a higher pressure
Your losing fluid throughout the capillaries during exercise b/c blood pressure increases
Job of getting the fluid back is the job of the lymphatic system
Function of Lymph Nodes
Filters Their job is to catch foreign invaders WBC are located in the lymph nodes Infections are fought by building up WBC a. Increase population of WBC b. Lymph nodes become engorged with WBC, making them sensitive to touch
What happens when interstitial fluid is brought into the lymphatic vessels?
it becomes lymph and their compositions become the same
Edema
fluid build up in the tissues
Job of the Spleen
Job of the spleen is to get rid of defective red blood cells
Red blood cells do not live very long
They do not have a nucleus
They cannot make proteins b/c they do not have the machinery or instructions to do so
Essentially repositories for hemoglobin
Spleen is also a small reservoir for our blood
What happens to the spleen during exercise?
The spleen volume can be reduced by 40 – 50%
The red blood cells are pushed out into the general circulation
Blood has a better oxygen carrying capacity than at rest
Average blood pressure between venous and arterial side
On the venous side of things there is only 1 pressure, there is no pulse
In arterial side you go from systolic pressure to diastolic and then back up to systolic etc
• The rise in pressure is very swift and then the reduction in pressure is much slower; fall in blood pressure is mitigated by the elastic recoil of the arterial wall
How do we calculate the average blood pressure?
Average pressure = 1/3 of the way between systolic & diastolic
Mean = Diastolic + (1/3)Pulse Pressure
Baroreceptors
Located in the some of the big arteries (aortic arch, carotid arteries)
Pretty much stretch receptors
As pressure rises, they are stretched more and their firing rate increases
Controls tension on the veins and ensuring proper pressure and venus return
Chemoreceptors
Carotid arteries & other cerebral vessels (ether cerebral vessel)
Maintain proper blood flow to the brain
A drop in blood pressure in the brain, causes an increase in carbon dioxide and receptors respond by triggering dilation of blood vessels to bring blood to the brain
If blood pressure too high—will remove carbon dioxide too quickly from the brain; pH will increase; trigger vasoconstriction of the blood vessels
What happens when you go from lying position to standing?
Venous return goes down as blood pools;
End-diastolic volume goes down b/c you are not getting venous return;
So stroke volume also falls which means;
Reduced cardio output;
Blood pressure is lower, not stretching the arteries like you should;
Baroreceptors sense the decrease in stretch, send message to Medulla Oblongata
Medulla Oblongata triggers:
Increase heart rate; thereby increasing cardiac output
Increase peripheral resistance by constricting the arterioles and the veins;
Resulting in increase blood pressure again
Placenta
Fetal tissues
Umbilical Artery
takes blood to the placenta
Umbilical Vein
brings blood back to the baby
Does the umbilical vein go to the baby’s heart first?
No, the umbilical vein goes to liver first so it gets all of the nutrients from the mother before it goes to the vena cava
Ductus Arteriosus
between pulmonary trunk and the aorta
Foramen Ovale
between the atria
Blood Plasma
liquid part of the blood
“Formed Elements” in Blood
RBC (erythrocytes)
WBC (glucocytes)
Platelets (thrombocytes)
Erythrocytes
RBC
Glucocytes
WBC
Granular WBC
Eosinophils - stains pink with Eosin dye
Basophils - stains blue in basic dye
Neutrophils - unstain in acid or basic dye
Basophils
Stains blue in basic dye
Produce heparin, which helps blood not clot during circulation
Granular
Neutrophils
Unstain in acid or basic dye
Phagocytes
Granular
Agranular WBC
Monocytes & Lymphocytes
Monocytes = phagocytic cells
Lymphocytes = specific immune responses
Albumins
60-80% of total plasma proteins
All produced in the liver
Smallest from liver
Used for maintaining the osmotic concentration of the plasma
Globulins
3-D shape
Alpha—used for transport from liver
Beta—used for transport from liver
Gamma—made by lymphocytes (= antibodies)
What happens to your fluid when you exercise?
vasodilate the arterioles of the skeletal muscles to a greater blood flow, going to lose more fluid there, have a higher blood pressure; need a greater lymph production to get that fluid back
Hemopoiesis
making of blood cells
takes place in the red bone marrow
Erythropoietia
Hormones (from kidneys)
Stimulates RBC production
If oxygen levels fall too low, kidney stimulates production of this hormone, which the hormone then stimulates the stem cells to make the RBC; get carrying capacity of oxygen back up to normal
Hematocrit
% of whole blood that is “cells”; formed elements
Plasma
fluid part of the blood
Blood Serum
fluid left after clotting occured
What happens if the walls of a blood vessel are damaged? how does it repair itself?
Vasocontrict vessel—less blood flow & less leakage, makes it easier to repair
Form a platelet plug, not a permanent fix but it’s a good start
Form thrombus (which is the clot)—the more solid patch
Repair vessel wall & then dissolve thrombus
What about thrombocytes make them advantageous to repair the walls of a broken blood vessel?
Thrombocytes (platelets), do not stick together or the inner walls but they do stick to collagen→ outside of the blood vessels
Breach in the wall, the platelets leak out along with the plasma and they then encounter collagen and they stick to it;
So the collagen surrounds the blood vessels, so if there’s a breach, the thrombocytes will stick to the collagen that’s there
Then we have platelet release reaction
What happens during platelet release reaction?
Release ADP—makes platelets stickier; helps the platelet plug form
Seratonin & Prostoglandins—stimulate vasoconstriction of the smooth muscles; less blood flow through broken vessel
Phospholipids & Calcium—needed in sequence of reaction for clot formation; the phospholipids are going to help in the formation of the thrombus to get that fibrin mesh work set up
what produces fibrinogen? and what is fibrinogen?
the liver produces fibrinogen which is a plasma protein
fibrinogen will be converted into fibrin but in order to be converted into fibrin; thrombin is the enzyme that is needed for the conversion for fibrinogen
thrombin has its own inactive form, prothrombin; there is a cascade of these events/enzymes that need to go right
Hemophilia
Disorder where certain clotting factors are missing or inappropriate so they have a delay in the formation of a blood clot
On the X chromosome so men are more at risk than women because women have 2 Xs because the normal gene overpowers the mutated gene, in guys if you have 1 your screwed
How does Aspirin affect blood clotting?
it inhibits prostoglandins; which are used for vasoconstriction
Bruise
a blood clot under the skin
Scab
a blood clot on the surface
