Circulatory System (Exam II) Flashcards
What is the primary function of the circulatory system?
Transport O2, CO2, Nutrients, (to the tissue) and remove metabolic waste (from the tissue)
What are the secondary functions of the circulatory system?
Thermoregulation
Transport of immune cells
Transport of hormones
Vascular system consisting of heart and blood vessels
Blood vascular system
What are the two components of the circulatory system?
Pulmonary circulation and systemic circulation
Describe the route of pulmonary circulation:
Right atrium -> right ventricle -> pulmonary artery -> lungs-> pulmonary vein -> left atrium
Describe the path of systemic circulation:
Left atrium —> Left ventricle —> aorta —> rest of body
What is the name for extravascular fluid?
Lymph
Passive drainage system for returning extravascular fluid (lymph) to blood vascular system:
Lymph vascular system
What does the lymph vascular system lack?
Intrinsic pump
Due to absence of pump, the lymph vascular system relies on: (2)
Muscle contraction and body movement
What type of circulatory systems do humans have?
Closed circulatory system
The closed circulatory system is divided into pulmonary circulation that occurs on the ____ side of the heart and systemic circulation that occurs on the ____ side of the heart.
Pulmonary = right side
Systemic = left side
The two major types of circulatory systems:
Open and closed
Circulatory system in which there are no vessels, but contains a heart that pumps fluid around that circulates within body cavities
Open
What is the limiting factor of an open circulatory system:
Body size (once you exceed a certain body size, it becomes inefficient)
Circulatory system in which the blood is contained within vessels/ plumbing of the body:
Closed circulatory system
The systemic circulatory system takes ____ and distributes it to the rest of the body.
Oxygenated blood
Blood vessels of the circulatory system have a common basic structure with:
Three concentric layers
The 3 concentric layers of the blood vessels are commonly referred to as:
Tunics
The innermost vascular tunic:
Tunica intima
What type of cells comprise the tunica intima:
Simple squamous endothelial cells lining lumen
The innermost layer of simple squamous endothelial cells lining the lumen
Tunica intima
Describe the thickness of the tunica intima:
1-2 cells thick- very thin
The tunica intima forms a ____ barrier supported by _____.
Semi-permeable barrier supported by a basement membrane
Specialized discontinuous tight junctions between endothelial cells of the tunica intima:
Fascia occludens
What do the fascia occludens of the tunica intima do?
Allows WBCs to extravasate
The tunica intima contains variable amounts of:
Subendothelial connective tissue
If present, separates the tunica intima from the tunica media
Internal elastic lamina
What makes up the internal elastic lamina?
Elastic fibers
The highly variable middle layer (vascular tunic)
Tunica media
The tunica media is comprised of:
Smooth muscles cells and fibroblastic connective tissue
In arteries, the tunica media is:
The thickest of layers
In arteries the tunica media may contain:
Reticulin (type 3 collagen) & elastic fibers
In veins, the tunica media tends to be:
Somewhat thinner
What is reticulin?
Type III collagen
If present, located between tunica media and tunica adventitia
External elastic lamina
What two layers may or may not be present in a vessel?
Internal and external elastic lamina
Describe arrangement of elastic fibers in external elastic lamina?
Not well organized
What determines an inner or outer elastic lamina will be present?
Size of vessel
The outermost layer (vascular tunic)
Tunica adventitia
The vascular tunic that is comprised of loose fibroblastic connective tissue
Tunica adventitia
The tunica adventitia contains:
Loose fibroblastic connected tissue and fibroblasts, collagen, elastic fibers, and smooth muscle cells
Describe thickness of tunica adventitia in arteries:
Thin
Describe thickness of tunica adventitia in veins:
Thickest
In larger vessels, the tunica adventitia may contain:
Vasa vasorum
Small blood vessels that supply the tunica media and tunica adventitia in both large arteries and veins:
Vasa vasorum
The tunica adventitia contains what type of nerves?
Autonomic nerves
The autonomic nerves of the tunica adventitia:
Nervi vasculares
Responsible for the contraction of smooth muscle in vessel walls:
Nervi vasculares
What two functions are the Nervi vasculares responsible for?
Vasconstriction and vasodilation
Most common fiber of tunica adventitia:
Fibroblasts
Decrease of lumen diameter due to action on smooth muscle of tunica media by sympathetic post ganglionic nerve fibers
Vasoconstriction
Vasoconstriction is due to the action of what nerve fibers?
Sympathetic post ganglionic
The three debated causes of vasodilation:
- Absence/inhibition of sympathetic stimulation
- Accomplished via indirect paratsympathetic innervation
- When oxygen tension in cells is low causing smooth muscle to relax
When Endothelial cells to release NO (Nitrous oxide) which secondarily causes smooth muscles to relax, this is an example of vasodilation caused by:
Indirect parasympathetic innervation
In response to low oxygen tension, smooth muscle in wall of arterioles:
Relax causing vasodilation
Specialized sensory receptors located in the walls of blood vessels (2)
Baroreceptors and chemoreceptors
Specialized sensory receptor located in carotid sinus and aortic arch
Baroreceptor- detect BP
Baroreceptors detect blood pressure by:
Detecting stretch in walls of vessel
Specialized sensory receptor located at bifurcation of carotid aorta and in aortic bodies of the aortic arch
Chemoreceptors
Chemoreceptors function by:
Detect changes in composition of blood (O2, CO2, pH)
How do chemoreceptors monitor pH?
By monitoring hydrogen ion concentration
What system conducts blood AWAY from the heart and TO the capillary bed
Arterial system
What system returns blood FROM capillaries and TO heart?
Venous system
Cyclical pumping of heart causes:
Pulsatile blood flow
Contractions of ventricles:
Systole
Systole causes:
Pressure wave
Relaxation of the heart:
Diastole
Diastole causes:
Decrease in pressure
Normal blood pressure:
120/80 mm Hg
Expansion and recoil of _____ maintains blood pressure
Elastic arteries
Regulation of blood pressure is accompanied by changes in:
Diameter of blood vessels
Regulation of BP is accompanied by changes in diameter of blood vessels; occurs via ______ control of _____ in vessel walls
Sympathetic control; smooth muscle
Arteries contain larges amounts of _____ & _____
Elastin & smooth muscle
In arteries, the vessel wall is _____ relative to lumen diameter
Thick
What two arteries carry unoxygenated blood?
Pulmonary and umbilical
What determines the name of the vessel?
The direction of blood flow relative to the heart
What causes an ejection of blood volume in the heart?
Systole
A drop in BP is commonly seen in what phase of blood pressure?
Diastole
In the case of elastic arteries, the large volume of elastin in the walls of these vessels minimizes ____ and encourages ____.
Expansion and encourages elastic recoil.
The large amounts of collagen and elastin in the arterial wall, promotes a more:
Rigid vessel
When blood vessels constrict the pressure:
Increases
When blood vessels relax, pressure:
Decreases
Blood pressure thorough the body is regulated by change diameter in vessel size- accomplished by sympathetic control of smooth muscle in the:
Tunica media
What is the size of elastic arteries?
Greater than 1cm in diameter
What are the large conducting blood vessels that receive blood directly from the heart?
Elastic arteries
What are the examples of elastic arteries? (4)
- Aorta
- Common carotid
- Subclavian
- Pulmonary artery
Elastic arteries have sheets of elastic tissue in the:
Tunica media
In elastic arteries, there are sheets in elastic in the tunica media help to:
Helps to maintain BP between systole and diastole
Thickest layer of elastic artery?
Tunica media
Elastic arteries possess both:
Internal and external elastic lamina
If the blood vessels takes up the entire slide it’s most likely:
Elastic artery
What is the diameter of muscular arteries?
~2-10 mm
Medium sized distributing arteries
Muscular arteries
Arteries that have more smooth muscle and less elastin in tunica media when compared to elastic arteries:
Muscular arteries
Thickest layer in muscular artery?
Tunica Media
A muscular artery contains a distinct _____; while a larger muscular artery may also contain _____.
Internal elastic lamina; external elastic lamina
Diameter of arterioles:
~10-100 micrometers
Vessels containing relatively little smooth muscle:
Arterioles
The tunica media of arterioles is around:
~2-3 cells thick
Absent in arterioles:
Elastic lamina
The terminal branches of arteriole system supplies:
Capillary beds
Arterioles provide the major sites of:
Vasoconstriction and vasodilation
Arterioles regulate the distributions of blood via:
Pre-capillary sphincters
What are the intermittent rings of smooth muscle within walls of arterioles
Pre-capillary sphincters
What are small diameter arterioles that are intermediate in size between arterioles and capillaries?
Metaarterioles
Metarterioles are in between the size of:
Arterioles & Capillaries
In general, the amount of smooth muscle ___ with increase in diameter of vessel (and the relative amount of connective tissue ____)
Smooth muscle increases
Connective tissue decreases
Last blood vessels that you would see before capillary ends?
Met arterioles
In a Metarteriole, the tunica media has become so thin that it is no longer _____.
Continuous
Concerned with exchange of gases, fluids, nutrients, metabolites, & waste products
Microcirculiation
What are the components that microcirculation is concerned with? (Exchange of:)
- Gases
- Fluids
- Nutrients
- Metabolites
- Waste products
Microcirculation occurs primarily within ____ but also includes ____ & _____.
Capillaries
Arterioles & Venules
What are the thin walled vessels ~8-10 micrometers in diameter?
Capillaries
Capillaries are lined by thin ____ layer of ___ cells.
Single; endothelial
What are capillaries supported by? (2)
Basal lamina & small #’s of pericytes
What regulates blood flow to capillaries themselves?
Arterioles
Major sites of exchange of nutrients and oxygen in tissues; very thin walled vessels
Capillaries
Generally, fluid leaves circulatory system in:
Capillaries
Capillaries lack _____ & _____, so they are nothing more than tunica intima with some pericytes and collagen
Tunica media & Tunica adventitia
____ are derived from same precurser cells as endothelial cells
Pericytes
Pericytes can differentiate into: (following injury)
Endothelial cells or smooth muscle cells
Capillaries do not exhibit:
Vasomotor activity themselves
Vasoconstriction & Vasodilation are accomplished smooth muscle contraction in arterioles & pre capillary sphincters which results in:
Passive change in capillary diameter
What are the types of capillaries? (3)
- Continuous
- Fenestrated
- Discontinuous
Type of capillary where endothelium forms continuous lining
Continuous capillary
What is the most common type of capillary?
Continuous capillary
Examples of where you night find continuous capillaries? (3)
Muscle, Lung, CNS
A type of capillary that the endothelium forms a continuous lining to prevent lymph form leaking out; endothelial cells fit together like pieces of a puzzle
Continuous capillary
The type of capillary in which the endothelial cells possess pore, or fenestrae within the cells:
Fenestrated capillary
In fenestrated capillaries, where are the fenestrae located in relation to the endothelial cell?
Within endothelial cell
Capillaries that allow large molecular weight stuff to pass through the endothelial lining, or with hormones, you want them to leave the vessel and go to surrounding tissue
Fenestrated capillaries
Where are fenestrated capillaries found? (2)
Endocrine system, and GI tract
The type of capillary where the basal lamina is not continuous:
Discontinuous capillary
The type of capillary where the endothelial cells are separated by large gaps BETWEEN cells
Discontinuous capillary
What is the most leaky type of capillary?
Discontinuous
Discontinuous capillary may form large open spaces called:
Sinusoids
Where can discontinuous capillaries be found? (4)
Liver, spleen, bone marrow, Inn)
Transport across capillaries may occur via: (3)
Fenestrae, transcytosis, or diapedesis
Label the types of capillaries
Top to bottom:
- Continuous
- Fenestrated
- Discontinuous
Label image
- Junctions- continuous capillary
- Fenestrae- fenestrated capillary
- Spaces- discontinuous
System that functions as a low pressure collecting system for returning from capillary beds to heart
Venous system
Venous contains vessels with ___ walls and _____ Relative luminal diameter in comparison to corresponding arteries
Thinner walls
Larger relative luminal diamter
In the venous system, there are fewer layers of smooth muscle in _____ compared to similar sized arteries
Tunica media
What is the thickest of the 3 layers in veins?
Tunica adventitia
In veins what prevents backflow (especially in limbs and thorax)
Valves
Valve failure in legs results in:
Varicose veins
Why is there a higher likelihood of stagnation in the veins versus arteries?
Gravity
Because of ____ its okay to remove veins, the blood will just go to a different vein route.
Colateral circulation
Small veins =
Venules
Lack elastic lamina, and potentially even tunica media in the smaller ones
Venules
~10-50 micrometers; both tunica media and adventitia is reduced or absent
Post-capillary venules
Post-capillary venules is a preferential site for:
Diapedesis
Venules drain into larger ____, then into _______
Collecting venules ——> muscular venules
A type of venule with thin smooth muscle layer in tunica media
Muscular venules
What type of substances act on venules?
Vasoactive substances
What are examples of vasoactive substances? (2)
Histamine and serotonin
Vasoactive substances ____ intercellular spaces
Enlarge
Ultimately vasoactive substances:
Increase permeability of vessel
The smallest of the venules:
Located immediately after the capillary bed
Downside of vasodilation in venules:
Leakiness = edema
Large and medium sized veins are called:
Muscular veins
Small muscular veins may or may not contain:
Internal elastic lamina
Medium muscular veins contain only:
Internal elastic lamina
Large muscular veins contain:
Internal and external elastic laminae
____ in the tunica media of veins control luminal diameter of muscular veins and venules
Smooth muscle
To determine difference between muscular artery and vein, you’d look at:
Wall thickness & Lumen diameter
Direct connections between arterial and venous system
AV shunts
AV shunts bypass:
Capillary bed
AV shunts are a type of:
Anastomosis
AV shunts are commonly found in ____ and function in _____.
Skin; thermoregulation
Vein or artery directly connecting two capillary beds
Portal vessels
Example of portal vessels: (1)
Hepatic portal vein
____ of the venous portal system connects the capillary bed of the small intestine, to the capillary bed of the liver.
Hepatic portal vein
The idea is that in a shunt, blood detours around capillary bed to: (in AV shunts)
Preserve heat
When endothelial vessel is damage, cholesterol adheres to exposed proteins to form a:
Cholesterol patch
Once the endothelium heals (after the vessel damage & cholesterol patch):
Cholesterol patch is reabsorbed
When endothelium of vessel is damaged, cholesterol adheres to:
Exposed proteins
After healing of the damaged endothelial vessel, the cholesterol is phagocytosed by _____.
Macrophages
After healing and after the cholesterol is phagocytosed by macrophages, further phagocytosis occurs by:
Endothelial and subintimal cells
The endothelial & subintimal cells that later phagocytose the cholesterol patch form:
Foam cells
What types of cells compose foam cells?
Endothelial and subintimal cells
What is the purpose of the cholesterol patch formation when and endothelium is damaged?
Prevents initiation of clotting cascade
Following damage to endothelium of vessel, if inflammatory response becomes chronic this results in: (condition)
Atherosclerosis
Following damage to endothelium of vessel, if inflammatory response becomes chronic this results in: (what is formed)
Plaque
In atherosclerosis, the plaque formation can be:
Generalized or focal
If you have high cholesterol and the cholesterol patch persists, the macrophages come in and try to engulf the cholesterol. But, there is so much cholesterol that the macrophages have to recruit other cells to come and these different cells have ____.
Cholesterol vacuoles
In atherosclerosis, all the recruited cells with cholesterol vacuoles begin to take on the appearance of:
Brown fat
When cholesterol patch persists (in case of atherosclerosis) we get the development of:
Foam cells
What minimizes the effects of atherosclerosis
Vitamin C
In the later stages of atherosclerosis, you get the proliferation of ____ cells and formation of:
Smooth muscle cells, and formation of fibrous connective tissue capsule
In atherosclerosis, the formation of the connective tissue capsule around the plaque is formed by fibroblasts migrating in and producing:
Collagen
In atherosclerosis, the presence of collagen around the plaque results in the limited ability for ___ and ____ to get into the plaque ultimately resulting in ______ & ______.
Oxygen and nutrients
Necrosis & secondary calcification
In atherosclerosis, the necrosis and secondary calcification is also known as:
Hardening of artery
In atherosclerosis, as plaques thicken and enlarge, the vessel lumen size decreases and this results in:
Elevated systolic BP
Atherosclerosis is often associated with what condition:
Hypertension
What is the most common cause of ischemic heart disease?
Atherosclerosis
In ischemic heart disease due atherosclerosis, the lumen of the coronary artery may decrease by:
90%
Gradual narrowing of lumen in vessel:
Stenosis
Gradual narrowing (stenosis) of vessel by plaque:
Thrombosis
Thrombosis can also be referred to as _____ of a vessel.
Occlusion
As plaque enlarges, or if endothelium is damages, this exposes:
Underlying collagen
Decreased oxygen uptake by tissue:
Anoxia
Heart becomes anoxic the resulting chest pain is known as:
Angina
______ formation initiates the clotting cascade:
Thrombus
Broken off piece of thrombus:
Embolus
If a piece of thrombus breaks off, this causes:
Thromboembolic disease
Sudden occlusion by embolus=
Acute ischemic event
During an acute ischemic event what two symptoms results:
Anoxia & Angina
If ischemia is untreated and resulting in portion of muscle dying, this is called:
Myocardial infarction
Death of muscle by ischemia:
Myocardial infarction
In myocardial infarctions, what cell is terminally differentiated?
Cardiac muscle cell (myocytes)
Because the myocytes are terminally differentiated, they are unable to:
Regenerate
Due to the myocytes inability to regenerate, if a portion of the muscle dies, we need:
Fibroblasts to produce collagen
Problem with fixing gap in cardiac muscle with collagen rather than muscle?
Collagen isn’t as stretchy like the original muscle was
All healing during MI has to occur via:
Fibrosis
Due to the connective tissue replacement (from MI), the loss of contactility results in:
Decrease or partial loss of function
During prolonged ischemia, in addition to MI, ____ can also be effected.
Heart valves
Inflammation and thinking of AV valves often associated with valvular incompetence leads to:
Increased turbulence & regurgitation
When inflammation and thickening of the AV valves occurs leading to increased turbulence and regurgitation, this leads to what conditions:
Vegetative endocarditis & Thromboembolic disease
Similar to MI except it affects the brain instead of heart:
Stroke
In a stroke, issues occur because ____ are terminally differentiated.
Neurons
What stage are both cardiac muscle cells and neurons stuck in?
Go (G NOT PHASES)
The loss of neurons caused by inability to receive oxygen and nutrients, ultimately results in:
Cerebral infarct
Cerebral infarct basically means our cells are _____, and we have a ______
Dead; loss of function
In a stroke, what determines the symptoms and severity of a clot:
Location of clot
Occurs when blood vessels dilate to form thin-walled balloon-like regions:
Aneurisms
Aneurisms are common in the:
Aorta and brain
Middle aged Asian women are at an increased risk of developing ______ (numerous bleeding little blood vessels) and the effect can be cumulative over time.
TIAs
The lymph vascular system is structurally similar to:
Veins
The lymph vascular system is structurally similar to veins but the endothelial cells:
Are thinner and have greater permeability
Lymph endothelial cells are highly active in:
Phagocytosis
The lymph vascular system has very thin:
Tunica media
____ are present in the lymph vascular system
Valves
What may or may not be present in the lymph vascular system?
Pericytes and basement membrane
What is the excess fluid that the lymph vascular system drains?
Lymph
The lymph vascular system is responsible for drainage of lymph from where and returns it to where:
ECS and returns it to blood stream
Lymph is formed as a result of:
High hydrostatic pressure in arterioles
In arterioles, the high hydrostatic pressure exceeds the _______ exerted by plasma proteins
Colloidal oncotic pressure
In the lymph vascular system, when the high hydrostatic pressure in arterioles exceeds the colloidal oncotic pressure exerted by plasma proteins this results in leakage of: (what and where)
water, electrolytes and plasma proteins from capillaries into ECS
Lymph is very high in:
Protein
The ECS is drained by a series of:
Interconnected, blind-ending tubules
The ECS is drained by a series of interconnected, blind-ending tubules called:
Lymphatics
The lymphatics converge on the:
Thoracic duct & right lymphatic duct
What is the largest lymph vessel in the body?
Thoracic duct
Thoracic duct and right lymphatic duct both contain:
Tunica media
Lymph returns to the blood stream at junction of:
Left internal jugular vein & Left subclavian vein
Because the lymph vascular system relies on body movement and contraction of skeletal muscle, immobility may lead to:
Peripheral edema (swollen feet)
What are interspersed along lymph vessels?
Lymph nodes
Contain lymphoid tissue for antigenic sampling and recognition; activation of immune cells and production of antibodies:
Lymph nodes
Asymmetrical lymph drainage is important in:
Tumor metastasis
Thin walled, lack blood, contain smooth, eosinophilic, proteinaceous fluid (lymph), occasional WBCs
Lymph node
The basement membrane in lymph nodes is ____ or ______.
Rudimentary or absent
Antigen sampling ——> Immune activation ——-> Lymph trap!
Lymph nodes
In some areas of the body especially the _____, lymphatic drainage is asymmetrical.
Thorax
Disease due to fallarid worm, they like the inguinal lymph nodes and they obstruct the return of lymph to the periphery:
Elephantiasis
