Circulatory System (Exam II) Flashcards
Primary function of the circulatory system
- transport O2 (to tissue)
- transport CO2 (to tissue)
- transport nutrient (to tissue)
- transport metabolic waste (from tissue)
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
Two components of the circulatory system
Pulmonary circulation
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
Extravascular fluid
Lymph
Passive drainage system for returning extravascular fluid (lymph) to blood vascular system
Lymph vascular system
The lymph vascular system lacks:
An intrinsic pump
Due to absence of pump, the lymph vascular system relies on: (2)
Muscle contraction
Body movement
Type of circulatory system humans have
Closed
The closed circularity 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 system
Open
Closed
Circulatory system in which there are no vessels but contains a heart that pumps fluid around to circulate in body and bathes tissues
Open
Limiting factor of an open circulatory system
Body size
(Once you exceed certain body size, it becomes less efficient especially in lower extremities)
Circulatory system in which the blood is contained within vessels/plumbing of the body
Closed
The systemic circulatory system takes _____ and distributes it to rest of body
Oxygenated blood
Blood vessels of the circulatory have a common basic structure with:
Three concentric layers
The three concentric layers of the blood vessels are commonly referred to as:
Tunics
Innermost vascular tunic
Tunica intima
Type of cells comprising the tunica intima
Simple squamous endothelial cells lining lumen
Describe thickness of tunica intima
1-2 cells thick; very thin
The tunica intima forms a ______ supported by _____
Semi-permeable barrier
Basement membrane
Specialized discontinuous junctions contained between the endothelial cells of the tunica intima
Fascia occludens
Function of the fascia occludens of the tunica intima
Allow WBC to extravasate
Tunica intima contains variable amounts of
Subendothelial connective tissue
If present, separates the tunica intima and a tunica media
Internal elastic lamina
Makes up the internal elastic lamina
Elastic fibers
Higher variable middle layer (vascular tunic)
Tunica media
Tunica media is comprised of
Smooth muscle cells
Fibroblastic connective tissue
In arteries, the tunica media is:
Thickest of layers
In arteries, the tunica media may contain:
Reticulin (type III collagen)
Elastic fibers
In veins, the tunica media tends to be:
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 & external elastic lamina
Describe arrangement of elastic fibers in external elastic lamina
Not well organized
determines if an inner or outer elastic lamina will be present
Size of vessel
Outermost layer (vascular tunic)
Tunica adventitia
Vascular tunic comprised of loose fibroblastic connective tissue
Tunica adventitia
Tunica adventitia contains
Loose fibroblastic connective tissue
Fibroblasts
Collagen
Elastic fibers
Smooth muscle cells
Describe thickness of tunica adventitia in arteries
Thin
Describe thickness of tunica adventitia in veins
Thickest
In larger vessels, 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
Types of nerves contained within the tunica adventitia
Autonomic nerves
The autonomic nerves of the tunica adventitia
Nervi vasculares
Responsible for smooth muscle contraction in vessel wells (vasoconstriction & vasodilation)
Nervi vasculares
Two functions of the Nervi vasculares
Vasoconstriction
Vasodilation
Most common fiber of tunica adventitia
Fibroblasts
Decrease in lumen diameter due to the 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
Three debated causes of vasodilation
1- absence/inhibition of sympathetic stimulation
2- accomplished via indirect parasympathetic innervation
3- when oxygen tension in cells is low causing smooth muscle to relax
When endothelial cells to release NO which secondarily causes smooth muscle to relaxe- this is an example of vasodilation caused by
Indirect parasympathetic innervation
In response to low oxygen tension smooth muscle in walls of arterioles:
Relax, causing vasodilation
Specialized sensory receptors located in the walls of blood vessels (2)
Baroreceptors
Chemoreceptors
Specialized sensory receptor located in the carotid sinus and aortic aortic arch; detect BP
Baroreceptors
Baroreceptors detect blood pressure by:
Detecting stretch in walls of blood vessel
Specialized sensory receptor located at bifurcation of carotid aorta and in aortic bodies in aortic arch; function to detect changes in O2, CO2 and pH
Chemoreceptors
Chemoreceptors function by:
Detecting changing in composition of blood (O2, CO2, pH)
How do chemoreceptors monitor pH
Monitoring hydrogen ion concentration
System that conducts blood AWAY from the heart and TO the capillary bed
Arterial system
System that returns blood FROM capillaries and TO the heart
Venous system
Cyclical pumping of the heart causes:
Pulsatile blood flow
Contractions of the 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 BP
Elastic arteries
Regulation of BP is accompanied by changes in:
Diameter of blood vessels
Regulation of blood pressure is accompanied by changes in diameter of blood vessels; it occurs via _____ control of _______ in vessel walls
Sympathetic control
Smooth muscle
Arteries contain large amounts of ____ and ____
Elastin
Smooth muscle
In arteries the vessel wall is _____ relative to lumen diameter
Thick
Two arteries that carry unoxygenated blood
Pulmonary
Umbilical
Determines the name of the vessel
Direction of blood flow relative to the heart
Causes an ejection of blood volume in the heart
Systole
A drop in BP is commonly seen in what phase of BP
Diastole
In the case of elastic arteries, the large volume of elastin in the walls of these vessels minimizes ____ and encourages ____
Expansion
Elastic recoil
Large amounts of collagen and elastin in the arterial wall promotes a more:
Rigid vessel
When blood vessels constrict, pressure:
Increases
When blood vessels relax, pressure:
Decreases
BP throughout the body is regulated by change in diameter and vessel size- accomplished by sympathetic control of smooth muscle in the:
Tunica media
Size of elastic arteries
Greater than 1 cm in diameter
Large conducting blood vessels; receive blood directly from heart
Elastic arteries
Examples of elastic arteries (4)
1- aorta
2- common carotid
3- subclavian
4- pulmonary
Elastic arteries contain sheets of elastic tissue in the:
Tunica media
In elastic arteries, the sheets of elastic tissue in the tunica media helps to maintain:
BP between systole and diastole
Thickest layer of elastic artery
Tunica media
Elastic arteries possess both:
Internal & external elastic lamina
If the blood vessel takes up the entire side it’s most likely:
Elastic artery
Diameter of muscular arteries
2-10nm in diameter
Medium-sized distributing arteries
Muscular arteries
Arteries that have more smooth muscle and less elastin the tunic 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
Tunica media of arterioles is around:
2-3 cells thick
Absent in arterioles
Elastic laminae
Terminal branches of arterial system supply:
Capillaries beds
Arterioles provide the major sites of:
Vasoconstriction & vasodilation
Arterioles regulate distribution of capillaries via:
Pre-capillary sphincter
Intermittent rings of smooth muscle within walls of arterioles
Pre-capillary spinchters
Small diameter arterioles, intermediate in size between arterioles and capillaries
Metarterioles
Metarterioles are in between size of:
Arterioles & capillaries
In general, the amping of smooth muscle _____ with increase in diameter of vessel (& relative amount of connective tissue ____)
Increases
Decreases
Last blood vessels you would see before capillary begins
Metaarterioles
In a Metarterioles, the tunica media has become so thin that it is no longer ______
Continuous
Concerned with exchange of gases, fluids, nutrients, metabolites and waste products
Microcirculation
Components microcirculation is concerned with (exchange of)
Gases
Fluids
Nutrients
Metabolites
Waste products
Microcirculation occurs primarily within ____ but also includes ___ & ____
Capillaries
Arterioles & venules
Thin walled vessels aroun 8-10 micrometers in diameter
Capillaries
Capillaries are lined by thin _____ layer of ____ cells
Single
Endothelial
Capillaries are supported by (2):
Basal lamina
Small # of pericytes
Regulate blood flow to capillaries to 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
Derived from same precursor cells as endothelial cells
Pericytes
Pericytes can differentiate into: (following injury)
Endothelial cells
Smooth muscle cells
Capillaries do not exhibit ______ themselves
Vasomotor activity
Vasodilation & vasoconstriction accomplished via smooth muscle contraction in arterioles & pre-capillary sphincters result in:
Passive change in capillary diameter
Types of capillaries
1- continuous
2- fenestrated
3- discontinuous
Type of capillary where endothelium forms continuous lining
Continuous capillary
Most common type of capillary
Continuous
Locations of where you may find continuous capillaries (3)
1- muscle
2- lung
3- CNS
Type of capillary where the endothelium forms a continuous lining to prevent lymph from leaking out
Continuous
Type of capillary in which the endothelial cells possess pores or fenestrae within cells
Fenestrated capillary
In fenestrated capillaries, where are the fenestrae located in relation to the endothelial cell
Within
Capillaries allowing for large molecule weight molecules to pass through the endothelial lining or with hormones - you want them to leave the vessel and go to surrounding tissue
Fenestrated
Location fenestrated capillaries may be found (2)
1- endocrine system
2- GI tract
Type of capillary in which basal lamina is NOT continuous
Discontinuous capillary
Type of capillary in which the endothelial cells are separated by large gaps BETWEEN cells
Discontinuous
Most leaky type of capillary
Discontinuous
Discontinuous capillaries may form large open spaces called:
Sinusoids
Location discontinuous capillaries may be found (4):
1- liver
2- spleen
3- bone marrow
4- Inn
Transport across capillaries may occur via: (3)
Fenestrae
Transcytosis
Diapedesis
Label the type of capillary and label A, B, C
1- continuous
2- fenestrated
3- discontinuous
A- junction
B- fenestra
C- spaces
System that functions as low pressure collecting system for returning blood from capillary beds to heart
Venous system
Venous system contains vessels with ____ walls and ____ relative luminal diameter in comparison to corresponding arteries
Thinner
Larger
In the venous system there are few layers of smooth muscle in _____ compared to similar sized arteries
Tunica media
The thickest layer in veins
Tunica adventitia
Prevents back flow in veins (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 the arteries)
Gravity
Because of _____ its okay to remove veins, the blood will just go to a different vein route
Collateral circulation
Small veins
Venules
Lack elastic lamina and potentially even tunica media (in the smaller ones)
Venules
Around 10-50 micrometers in diameter; both tunica media and adventitia is reduced or absent
Post-capillary venules
Post-capillary venules is the preferential site for:
Diapedesis
Venules drain into larger ______ then into ______
Collecting venules
Muscular venules
Type of venule with thin smooth muscle layer in tunica media
Muscular venules
Type of substances that act on venules
Vasoactive substances
Examples of vasoactive substances (2)
Histamine
Serotonin
Vasoactive substances ____ intercellular spaces
Enlarge
Ultimately vasoactive substances
Increase permeability of vessel
smallest venules located immediately after capillary bed
Post-capillary venules
Downside of vasodilation in venules
Leakiness= edema
Large and medium sizes veins
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 & external elastic lamina
_____ in the tunica media of veins controls luminal diameter of muscular veins and venules
Smooth muscle
To determine difference between muscular artery and vein, you look at:
Wall thickness
Lumen diameter
Direct connections between arterial & venous system
AV shunts
AV shunts bypass:
Capillary bed
AV shunts are a type of:
Anastomoses
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
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 AV shunts, blood detours around capillary bed to:
Preserve heat
When endothelial vessel is damaged, cholesterol adheres to exposed proteins to form a:
Cholesterol patch
once the endothelium has healed (after vessel damage and formation of cholesterol patch)
Cholesterol patch is reabsorbed
When endothelium of vessel is damaged, cholesterol adheres to:
Exposed proteins
After healing of damaged endothelial vessel the cholesterol is phagocytosed by:
Macrophages
After healing and after the cholesterol is phagocytosed by macrophages, further phagocytosis occurs by:
Endothelial & subintimal cells
The endothelial & subintimal cells that later phagocytose the cholesterol patch form
Foam cells
Type of cells composing foam cells
Endothelial & subintimal
Purpose of formation of choleserol patch following damage of endothelium
Prevents initiation of clotting cascade
Following damage endothelium of vessel, if inflammatory response becomes chronic this results in (condition):
Atherosclerosis
In atherosclerosis the plaque 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 in, 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 the cholesterol patch persists (in case of atherosclerosis) we get the development of:
Foam cells
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
Fibrous connective tissue capsule
In atherosclerosis, the formation of the connective tissue capsule around the plaque is formed by fibroblasts migrating in and producing ______ around the edges of the plaque
Collagen
The presence of collagen around the plaque in atherosclerosis, results in the limited ability for _____ and ___ to get into the plaque, ultimately resulting in _____ and ____
Oxygen & nutrients
Necrosis & secondary calcification
In atherosclerosis the necrosis and and secondary calcification is also known as
Hardening of artery
In atherosclerosis, as plaque thicken and enlarge the vessel lumen size decreases and you get corresponding:
Elevated systolic BP
Atherosclerosis is often associated with what condition:
Hypertension
Most common cause of ischemic heart disease
Atherosclerosis
In ischemic heart disease (due to 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 damaged it exposes:
Underlying collagen
Decreased oxygen uptake by tissue
Anoxia
When heart becomes anoxic the resulting chest pain:
Angina
______ formation initiates the clotting cascade
Thrombus
Broken off piece of thrombus
Embolus
If piece of thrombus breaks off this causes:
Thromboembolic disease
Sudden occlusion by embolus results in:
Acute ischemic event
During an acute ischemic event, what two symptoms present:
Anoxia
Angina
If ischemia is untreated, resulting in death of portion of muscle this is called:
Myocardial infarction
Death of muscle by ischemia
Myocardial infarction
In myocardial infarction what cells are terminally differentiated
Myocytes (cardiac muscle cell)
Because myocytes are terminally differentiated, they are unable to:
Regenerate
Due to the myocytes inability to regenerate, if a portion of heart 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 occur via:
Fibrosis
Due to the connective tissue replacement (collagen), the loss of contractility results in:
Decreased or partial loss of function
During prolonged ischemia, in addition to MI ____ can also be affected
Heart valves
Inflammation ad thickening 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 excepting for it affects the brain
Stroke
In a stroke, issues occur because _____ are terminally differentiated
Neurons
cell cycle stage are both myocytes and neurons stuck in
G0
The loss of neurons caused by inability to receive oxygen & nutrients ultimately results in:
Cerebral infarct
Cerebral infarct basically means our cells are ____ and we have a _____
Dead
Loss of function
Determines the symptoms and severity of clot in a stroke
Location of clot
Occurs when blood vessels dilate to form thin-walled, balloon-like regions
Aneurism
Aneurisms are common in the:
Aorta
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
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 a very thin:
Tunica media
_____ are present in the lymph vascular system
Valves
May or may not be present in lymph vascular system
Pericytes & basement membrane
Excess fluid the lymph vascular system drains
Lymph
The lymph vascular system is responsible for drainage of lymph from ______ and returns it to _____
ECS
Bloodstream
Lymph is formed as a result of:
High hydrostatic pressure & arterioles
In arterioles, the high hydrostatic pressure exceeds the ____ exerted by plasma proteins
Colloidal on 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 & where):
water, electrolytes, & plasma proteins from capillaries into ECS
Lymph is very high in
Protein
ECS is drained by a series of:
Interconnected, blind-ending tubules
ECS is drained by a series of interconnected, blind-ending tubules called:
Lymphatics
The lymphatics converge on the:
Thoracic duct & right lymphatic duct
Largest lymph vessel in body
Thoracic duct
Thoracic duct & right lymphatic duct both contain:
Tunica media
Lymph returns to the bloodstream 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)
Interspersed along lymph vessels
Lymph nodes
Contain lymphoid tissue for antigenic sampling & recognition; activation of immune cells and production of antibodies
Lymph nodes
Asymmetrical lymph draining is important in:
Tumor metastasis
Thin walled, lack blood, contain smooth, eosinophilic, proteinaceous fluid (lymph), occasional WBCs
Lymph nodes
The basement membrane in lymph nodes is ____ or ____
Rudimentary or absent
Antigen sampling —-> immune activation —-> _______
Lymph trap
In some areas of the body, especially the _____ lymphatic drainage is asymmetrical
Thorax
Disease due to fallarid worm- they like the inguinal lymph nodes & obstruct the return of lymph to the periphery:
Elephantiasis
