Week 10- Cardiovascular regulation (Cardio week 2) Flashcards
What is an arterial anastemoses function and example
Function is protective if we lose blood flow
Cirlce of willis
Funcion of arteriovenous anastomosis
Middle of capilary bed, provides a shunt to skip capillary bed
Define Arteries and veins
Arteries- going away from the heart
veins- going towards the heart
What are the 3 layers of blood vessel walls
External- Tunica externa (adventitia)
Tunica Media
Tunica Intima (interna) most internal
Which layer of blood vessil changees size when contrating/relaxing
Tunica media
What is the outter, protective layer of blood vessils called
Tunica externa (adventitia)
What is the layer of blood vessil wall that is continuous through all vessels and chambers, made of endothelial cells with basement membranes?
Tunica intima (interna)
What occurs When the tunica medial contracts
Vasoconstriction–> decreased blood flow
What occurs when the tunica media relaxes
Vasodialation–> increased blood flow
What kind of tissue is tunica externa, and what does it connect to
Connective tissue, connects to the tissue that the blood supplies
Which blood vessil layer is made of endothelial cells
tunica intima
What part of arteries are thicker than veins
Tunica media (muscle) is thicker (much more ability to change size of arteries, much higher pressure)
What part of veins are thicker than arteries
The Tunica externa is thicker
Where is the majority of our blood flow at rest
Systemic veins (resovoir for blood)
What is the function of the thick tunica media in arteries
Withstand high BP, change vessil size
What is the function of smaller arteries (describe their structure too)
Made of less elasticity and more smooth muscles, they are resistance vessils and are made of more smooth muscle so that they can control BP.
Is there more blood in arteries or veins
Always more blood in veins- 55% of blood in veins at rest
How do you mobilze the pooled blood in veins? (What type of nervous stimulation?)
- Increase SNS stimulation, cause vasoconstriction
- Muscle pump
The muscle pump is what and the mechanism is dependent on what?
Muscles smash veins when they contract, push blood back to heart. Mechanism is dependent on valves
Vein tunica externa function
support the vessels
Vein tunica intima function
Forms valves- this fights against gravity and maintains the movement of blood
What are the smallest veins called
venules (capitance vessels)
What are venous sinuses
High specialized flattened veins, very thin walls (ex. coronary sinus, dural venous sinus)
What are the smallest arteries called
Arterioles (resistance vessels)
Describe the pathway of the different types of arteries in the arterial system
Heart–> Elastic arteries (conducting arteries)–> Muscular arteries (distrubuting arteries)–> Arterioles (resistance vessels)
What 2 vessels are capillaries between
Between venules and arterioles
Function of capillaries
exchange between blood and tissues
What are capillaries made of
endothelium wall
What type of capillary beds skip capillaries and create arteriovenous anastamoses
Metaterioles
Blood cells go in a single file in what type of capillaries
true capillaries (smallest lumen diameter)
Describe continuous nonfenestrated capillaries
Continuous( basal lamina is continuous), non-fenestrated ( no holes in cells, no leakage)
Found in CNS, muscle, skin, allow for diffusion but control what enters and exits
Which type of capillary is the most common
continuous, non-fenestrated
Describe continuous, fenestrated capillaries
Basal lamina is continuous, there are little holes that allow diffusion and permiability to substances sometimes
Kidneys- allow for blood filtration
Endocrine glands- allow for secretion
Intestines- allow for absorbtion
Locations of continuous, fenestrated capillaries
Kidneys- filter blood
Endocrine glands- secretion
Intestines- absorbtion
Describe discontinuous capillaries
Basal lamina is not continuous from one cell to another
Most are sinusoidal/sinusoids
Gaps between allow high permiability for larger substances like proteins and cells
Where do you find discontinuous cpaillaries
Bone marrow, liver, spleen
Need RBCs to be able to get through
Function of discontinuous capillaries
Slow blood cells to modify them, put new blood cells and proteins into circulation
Roles of pericytes
Contractile to decrease permiability when contracting/increase when relaxing
Allow for the growth of new Blood Vessils
The blood flow in ml/min is equivalent to what in the whole body
cardiac output
What is blood pressure
Force/unit area exerted on vessel wall by the blood
What influences blood pressure
Cardiac output
blood volume
resistance to flow
What are some factors that increase resistance
Vessel length
Blood viscosity
Blood vessel size
What do pregnancy, normal growth, and obesity do to blood resistance
Increase resistance due to vessel lengths
Where does fluid accumulate in edema
interstitial space
Common causes of acites
liver failure- portal hypertension and low alblumin
Kwashiorkor- protein deficient diet that has decreased osmotic pressure in blood because the body can’t make protein
Where do Right and Left coronary arteries arise from
directly from aorta
What occurs to coronary blood vessels when HR increases
Coronary blood vessels dialate due to local chemical factors
What is angina
temporary blockage of coronary arteries
What is a MI
Heart attack, complete blockage of artery that leads to tissue death
What is a myogenic reaction
immediate- pressure directly changes vessel size
What vessels does a metabolic reaction impact
effects precapillary sphincters and arterioles
- Increased metabolism leads to dialation (i.e. higher temperature, higher K and lactate from muscles, low O2 in blood/High CO2)
- Decreased metabolism leads to constriction (i.e. low temperature, high O2, Low CO2, Low H+ ions, low temperature/lactate/K)
Local effects that lead to increased dialation
Low O2, High CO2, High H+ (low pH), High temperature
Effects that lead to constriction
High O2, Low CO2, Low H+/high pH, low temperature
What factor does low oxygen stimulate
HIF-1alpha
Which receptor type are most BV’s controlled by for constriction in sympathetic NS
Alpha 1
Which receptor type are most BV’s controlled by for dialation in sympathetic NS
Beta 2
Where are the important baroreceptors in the body
Carotid sinus (branch of glosopharyngeal n, carotid sinus n))
Aortic arch (Branch of vagus nerve, aortic depressor n))
What activates baroreceptors
increased pressure
What are the goals of the chemoreceptor reflexes
maintain oxygen levels
maintain pH via CO2 levels
(respond to O2, CO2, H+)
What is the common factor in all forms of shock
low blood flow
