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List the three circulatory circuits:
- 1. Pulmonary CIRCULATION
- 2. Systemic Circulation
- 3. Coronary circulation
List the two main functions of the lymphatic system
- 1. Return excess fluids
- 2. Immune system monitors fluid as its being returned, therefore it provides or a systemic monitoring system
Afferent vessels contain fluids moving _______the heart.
Efferent vessels contain fluids moving _______the heart.
Arteries are ___________________ vessels (regardless of oxygenation state!!!)
Veins are ___________________ vessels (regardless of oxygenation state!!!)
Discuss how there is movement from capillaries.
Capillaries form networks to supply the tissues, arteries flow into capillary beds, capillary beds drain into veins.
Vessel type, Main Function, Wall structure, other: Artery.
• Vessel type : Artery
- • Main Function : Move pumped blood to all areas of the body
- • Wall structure: Walls are thicker
- o smooth muscle layer is the thickest
- o Lumen is smaller then in veins.
- • Other: Higher BP,
- o More pronounced smooth muscle layer.
Vessel type, Main Function, Wall structure, other: capillary.
- • Vessel type : Capillaries
- • Main Function: Exchange of materials with tissue fluids
- • Wall Structure: 1 cell layer thick
- o Has only he endothelial layer
- • Other: High SA/V ratio makes diffusion across more efficient
- o Network of numerous vessels
Vessel type, Main Function, Wall structure, other: Veins.
- • Vessel Type: Veins
- • Main function: Return blood to heart
- • Wall structure: Lumen* is larger than arteries
- • Other: Have valves to aid in reducing backflow when working against gravity to return blood
What is a “lumen”?
The interior of a vessel, such as the central space in an artery or vein through which blood flows
An ___________________________ layer lines the lumen of all vessels. It is continuous throughout the vasculature as well as continuous with endocardium.
Vessel Wall Layer, Location, Cell type: Tunica Interna.
- • Vessel Wall Layer: Tunica Interna
- • Location: innermost
- • Cell type: Endothelium
Vessel Wall Layer, Location, Cell type: Tunica media
- • Vessel Wall Layer: Tunica media
- • Location: Middle layer, center
- • Cell Type: Smooth muscle cells
Vessel Wall Layer, Location, Cell type: Tunica externa
- • Vessel wall layer: Tunica Externa
- • Location: Most external layer
- • Cell type: Connective Tissue
List three types of efferent vessels. Which one has the smallest lumen?
- 1. Arteriole – Smallest lumen.
- 2. Muscular artery
- 3. Elastic Artery
What is usually true of all efferent vessels?
- • Tunica Media – thickest
- • Tunica Externa - thinnest
Describe the unique characteristics of arterioles.
- • Smallest vessels
- • Lumen 0.3-10 um
- • Function to distribute blood into capillary beds
Efferent vessels type, a.k.a., Function, Relative size, Tunica interna characteristics, Tunica media characteristics, Tunica externa characteristics: Arterioles.
- • Efferent vessels type: Arterioles
- • a.k.a.: nothing
- • Function: Transition into capillary bed
- • Relative size: smallest
- • Tunica interna characteristics: Similar to other arteries
- • Tunica media characteristics: 1-5 layers of smooth muscle and CT
- • Tunica externa characteristics: poorly developed
Efferent vessels type, a.k.a., example, Function, Relative size, Tunica interna characteristics, Tunica media characteristics, Tunica externa characteristics: Muscular Arteries.
- • Efferent vessels type: Muscular arteries
- • a.k.a.: distributing artery
- • example: Brachial or Radial Artery
- • Function: Take blood from large arteries and distribute them to other areas of the body
- o Help regulate BP
- • Relative size: Small/ Medium
- • Tunica interna characteristics: similar to that of other arteries – endothelial
- • Tunica media characteristics: lots of smooth muscle - thickest
- • Tunica externa characteristics: well developed
- o Helps form arteries
- o Anchors them
Efferent vessels type, a.k.a., example, Function, Relative size, Tunica interna characteristics, Tunica media characteristics, Tunica externa characteristics: Elastic Arteries.
- • Efferent vessels type: Elastic Arteries
- • a.k.a.: Conduction Arteries
- • Example: Aorta
- • Function: conduct blood from heart to vascular system
- o Large lumen
- o Elastic walls
- • Relative size: thick
- • Tunica interna characteristics: Thick
- • Tunica media characteristics: primarily elastic fibers with some smooth muscle and some CT
- • Tunica externa characteristics: is a thin layer
List the three types of capillaries:
- 1. Continuous capillaries
- 2. Fenestrated capillaries
- 3. Sinusoidal capillaries
Capillary type, description of endothelium, location: Continuous
- • Capillary type: continuous
- • Description of endothelium:
- o Thin uninterrupted layer (no pores)
- o Endothelial basal lamina is continuous (no pores)
- o Forms blood-brain barrier
- • Location:
- o Muscle tissue
- o Nervous tissue
- o Many CT sites
Capillary type, description of endothelium, location: Fenestrated – finestra – windows
- • Capillary type: Fenestrated
- • Description of endothelium: Endothelium interrupted by pores
- • Location:
- o Exists where filtration must occur
- o Endocrine glands
- o Intestinal tract
- o Kidneys
Capillary type, description of endothelium, location: Sinosoidal
- • Capillary type: Sinosoidal
- • Description of endothelium:
- o Large and leaky 20-40 um
- o Large irregular lumen
- o Discontinuous basal membrane (open spaces between endothelium and the underlying tissues)
- o Lined with phagocytic cells and endothelium
- • Location:
- o Liver
- o Hematopoietic organs (bone marrow/spleen)
- o Exchange macromolecules between blood and tissues
Afferent vessels type, Example, Function, Relative size, Tunica interna characteristics, Tunica Media, Tunica Externa:
- • Afferent vessels type:
- • Example: none
- • Function: Transition into capillary bed
- • Relative size: Smallest
- • Tunica interna chars: Endothelium
- • Tunica media Chars: 1-3 cell layers of smooth muscle
- • Tunica externa chars: Thick collagen fivers
Afferent vessels type, Example, Function, Relative size, Tunica interna characteristics, Tunica Media, Tunica Externa: Venules: Small/Medium
- • Afferent vessels type: Small/Medium
- • Example: found throughout the body
- • Function: Return blood from tissues
- • Relative size: Small/medium
- • Tunica interna chars: Endothelial and CT
- • Tunica media Chars: Varying amount of smooth muscle and CT
- • Tunica externa chars: Thick collagen fibers
Afferent vessels type, Example, Function, Relative size, Tunica interna characteristics, Tunica Media, Tunica Externa: Large Veins
- • Afferent vessels type: Large Veins
- • Example: Inferior/Superior vena cava
- • Function: Bring blood back to the heart
- • Relative size: Largest
- • Tunica interna chars: Well developed
- • Tunica media Chars: Smooth muscle and CT
- • Tunica externa chars:
- o Thickest layer
- o Lost of CT fibers
- o Has smooth muscle (only found in large veins)
Discuss the various adaptations of veins that aid in blood return.
- • Large lumens
- • Venous valves
- o Prevents blood from flowing backwards into veins
- • Venous sinuses (found in endothelium) = specialized flattened veins
Using the diagram below, describe how muscular action aids in blood return. How does this apply to the care of nonambulatory patients? What other features are diagramed below that aid in blood return?
- • No skeletal muscle action to help with blood flow
- • Valves, muscles
Cardiovascular health is reflected by the ability of the vascular system to regulate
- • Blood flow
- • Blood pressure
Blood flow is defined as :
The volume of blood flowing thought a given area in a given amount of time
Blood pressure is the force of the blood upon a given area of vessel wall. Measured in ______________ ____________ displaced in a column of mercury. It (increases/decreases) as you flow further away from the heart.
Blood flow rate is difficult to ascertain at a given moment or for the overall system as there is much variation. One must take into account:
- 1. Pulsating flow rate
- 2. Heart as a pump, not continuous, pulse
- 3. Vessels multibranched and elastic affecting flow rates
- 4. Blood is not a simple fluid
What is the formula for figuring average flow rate for a vessel? (Include what the letters stand for)
- Blood flow = the change in P over the change in R.
- • P = pressure
- • R = resistance
- • The difference in the in flow pressure and out flow pressure of b lood passing thought a vessel. Divided by the resistance to flow caused by the vessel.
Define “Blood Pressure”
The pressure exerted upon the walls of the vessels b the blood flowing through the vessels
In the blood pressure reading of 140/95, which number is the systolic pressure? Which is the diastolic pressure?
- • Systolic = 140
- • Diastolic = 95
Systolic pressure is the pressure due to the force of the pulse caused by ventricular __________.
Systole – contraction
Diastolic pressure is the pressure due to the force of pulse caused by ventricular_________.
Diastole - relaxation
What factors cause resistance to blood flow? Which are easily controlled? How?
- 1. Radius of blood vessel
- 2. Overall Length of blood vessel. (The further blood has to travel, the greater force will be needed to push it that far.)
- 3. viscosity of the blood.
To remember these principals, think of how easily you can drink a thick milk shake through a straw……….
- Which is easier to move through a straw, skim milk or a thick milk shake? – skim milk
- Which takes more force to move, a thick milk shake through a short straw or a long straw? Long straw
- Which takes more force to move, a thick milk shake through a skinny straw or an extra wide straw of the same length? – thick milk shake though a skinny straw
Describe the effect of vasoconstriction on blood pressure.-
- • decreased radius
- • increases resistance
- • decreased flow rate
- • increased BP
Define: Total Peripheral Resistance
The sum of all systemic vascular resistances
What are systemic vessels?
All vessels in the body
What does TPR stand for? (KNOW this acronym).
Total Peripheral Resistance
Chart the resistance given by each vessel type and the reason for those relative resistances. Vessel type, Relative resistance, Cause: Arteries
- • Vessel type: Arteries
- • Relative resistance: High, lower as you move further from the heart
- • Cause: Pulsing from heart pump
Chart the resistance given by each vessel type and the reason for those relative resistances. Vessel type, Relative resistance, Cause: Arterioles
- • Vessel type: Arterioles
- • Relative resistance: Highest
- • Cause: Small diameter
Chart the resistance given by each vessel type and the reason for those relative resistances. Vessel type, Relative resistance, Cause: Capillaries
- • Vessel type:
- • Relative resistance: Lowest
- • Cause: Abundant branching
Chart the resistance given by each vessel type and the reason for those relative resistances. Vessel type, Relative resistance, Cause: Veins
- • Vessel type: Veins
- • Relative resistance: Low, Slightly higher as near heart
- • Cause: Branches are pooling back together
List from highest to lowest the relative resistance of vessel types.
Arterioles > Arteries > Veins > capillaries
Since blood pressure and blood flow are affected by resistance, if follows that there are similar comparisons to be made.
In what vessel type is blood pressure the lowest?
In what vessel type is blood flow the slowest? How does this effect the ability of this vessel to complete its’ main function??
Capillaries – optimal exchange of materials
Define: precapillary sphincter
A sphincter in the metarteriole that controls the amount ofbblood that will flow into the capillary bed
Intermittent contraction and relaxation of smooth muscle in precapillay vessels
Define: Thoroughfare channel
Intermediate between a capillary and a venule
Vessel structurally intermediate between an arteriole and a capillary
Using the terms above, describe how blood flow through the capillary bed is regulated by the precapillary sphincters in the figure below.
- • When sphincters are open blood flows thought true capillaries
- • When sphincters are closed – blood flows thought metarterioles – thoughfare channels and bypasses true capillaries.
- Blood hydrostatic pressure
- Fluid pressure within capillaries – moves fluid out of capillaries
- Interstitial fluid hydrostatic pressure
- Pressure of interstitial fluid against the tissue and epithelial cells, moves fluid into capillaries
- Blood osmotic pressure
- Based on concentration of solutes in the blood
- Draws fluid into capillaries
- Interstitial osmotic pressure
- Based on the concentration of solutes in interstitial fluid
- Draws fluid out of capillaries
Describe the difference between osmotic pressure and hydrostatic pressure.
- • Osmotic - force under which water moves thought a semi permeable membrane. High concentration to low concentration. Moves out of low solute concentration and into higher solute concentration in attempts to equalize the solute concentration
- • Hydrostatic – pressure of water weight
What changes in blood cause changes in osmotic pressure?
Presence of nondiffusible solutes (plasma proteins)
What changes cause changes in hydrostatic pressure?
Fluid pressing against a wall
On either side of the capillary membrane is fluid, blood on the inside, interstitial fluid on the outside. Items will move across that membrane based on pressure differentials, both osmotic pressure and hydrostatic pressure. It is the overall sum of all the differences that determines how much and what moves across.
Where does excess fluid go?
Drained into the lymphatic system and returned to the circulatory system
How do extrinsic and intrinsic regulation methods differ? How are they alike?
- Extrinsic – systemic BP overall
- Intrinsic – local regulation, BP in brain, kidney, etc..
Extrinsic regulation of blood flow. List three methods of control
- 1. Sympathetic involvement
- 2. Parasympathetic involvement
- 3. Hormonal involvement
List two centers in the brain that give sympathetic control of blood flow systemically
- 1. vasomotor center in medulla
- 2. cardiac center in medulla
List 3 hormones that affect systemic blood pressure and blood flow
- 1. ADH
- 2. Angiotensin II
- 3. Histamines and Kinins
How does sympathetic control manage to change blood pressure/flow?
- Vasoconstriction will increase blood pressure
- Vasodilatation will lower blood pressure
- In systemic vessels, stimulation causes constriction, lack of stimulation causes dialation.
- Increase cardiac output, as well as TPR (what does TPR stand for?) therefore, what happens to blood pressure? Total Peripheral resistance
Describe the actions of the vasomotor center in the medulla oblongata
- • Controls the diameter of the BV
- • Maintains moderate vasoconstriction under most conditions
- • Receives info from baroreceptors etc.
- • Is Decreased impulse, increased vasodialation and decreased BP
- • Is increased impulse, decreased vasodilatation (vasoconstriction) and increases BP
What hormones are involved in regulation of blood pressure.
- Medullary – hypothalamus can regulate BP by influencing medullary center
- • ADH
- • Angiotensin II
- • Histamines and kinin
Discuss the role of Vasopressin in the regulation of blood pressure and return to homeostasis.
- • Releases in response to or more receptor stimulation
- • Causes vasoconstriction of arteries
- • Important in hemorrhage and dehydration
Discuss the role of Angiotensin II in the regulation of blood pressure and return to homeostasis.
• Vasoconstriction mechanism
What is the effect of Histamine and Kinin on the diameter of blood vessels? On systemic blood pressure?
- • Released during inflammatory process from mast cells, basophils etc.
- • Vasodilatation and decreases BP
- • Anti-histamines Increase BP – vasoconstriction
Now let us talk about INTRINSIC CONTROL of LOCAL BLOOD FLOW. List three classes of intrinsic control mechanisms
- 1. Autoregulation – of local blood flow to specific regions of the body
- 2. Myogenic control
- 3. Metabolic control
In what organs would local control be especially important?
- “myo-” refers to: Muscle
- “gen” refers to: origin
- • -goal: to maintain constant BP in specific capillary beds
- • -response to vessel wall stretch will cause local changes in BP by
Myogenic control when systemic BP is dangerously high (for the sensitive areas)
- • Precapillary vessels _______________________
- o Constrict
- • Capillary beds of local tissues get a more even blood flow, hence blood pressure
- -this mechanism protects LOCALLY from surges in BP
Myogenic control when systemic BP is dangerously low(for the sensitive areas)
- 1. LACK of stretching in precapillary muscles cause vessels to dialiate
- 2. Disproportionately large amounts of blood go into the capillary bed, so BP rises to a safe level.
Metabolic Control (intrinsic control, so again the goal is LOCAL regulation)
- 1. A decrease in the following factors LOCALLY will cause vasoconstriction
- i. -O2
- ii. -PH
- iii. -CO2
- 2. This causes a pooling of blood, metabolites accumulate
- 3. When enough have accumulated, this is sensed and the vasoconstriction will stop, causing a vasodilatation to end the local control.
Be able to summarize factors which affect blood pressure.
- Any factor effecting the follow will effect BP
- • Cardiac output
- • Blood volume
- • Peripheral resistance
- o Vasoconstriction/dilation
- o Viscosity of blood
- o Vessel blockage
Net filtration prerssure is all of the forces acting on the capillary bed
NFP = (HPc – Hpif) – (OPc – OPif)
State the properties shared by the circulatory pathways
- 1. Must service all areas of the body
- 2. Must supply critical areas even in cases of injur or blockage
- 3. Offer alternate routes
- 4. Vessels often chage names as they pass by landmarks
Vascular channels meet in several places proving alternate routes
Define: Collateral Circulation (Channels)
Alternate parallel pathways to the same area
Give an example of each
- Anastomosis – Palmar arch
- Collateral circulation – radial and ulnar arteries
Where does the subclavian artery turn into the axiallary artery?
When it passes under the clavicle
Where does the axillary artery turn into the brachial artery?
Passes under the inferior border of the teres muscle
Is there a Brachiochephalic artery on both sides? If not, on which side does it exist?
It exists on the left side
Left renal vein
- Inferior vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary semilunar valve
- Pulmonary trunk
- Right pulmonary artery
- Right lung
- R. pulmonary v.
- Left atrium
- Bicuspid valve
- Left ventricle
- Aortic semilunar valve
- Ascending aorta
- Aortic arch
- Descending thoracic aorta
- Descending abdominal aorta
- R. Common iliac a.
- R. external iliac a.
- R. femoral a.
- R. poplitial a.
- R. anterior a.
- R. dorsalis pedis a.
- R. arcuate a.
- R. metatarsal a.
- R. digital a. (of third digit if you think to write it.)
- Capillary bed of the third digit of the right foot.
- Challenge: To get the best practice on routing, you need to do many. Try this challenge:
- Go on the discussion board and post in the Vessels & Routs forum a thread asking for others to determine a route YOU choose following these rules:
- 1.The title of the thread is the route you are asking “from ____ to _____.”
- 2.Do NOT ask routes to the head or viscera that would need one to use vessels not on our list to know.
- Try out the routes other suggest. Post them as replies.
- Comment on the posts others make.
If many people participate in this challenge, a great variety of practice will be generated and all will benefit.