1/31 Exam 2 Howard Circulatory System Flashcards
What are the two parts of the circulatory system?
- blood vascular system (cardiovascular system)
- lymphatic vascular system
What is the function of the cardiovascular system?
Transports blood
What is the function of the lymphatic system?
Collects and transports lymph fluid back to blood vascular system
What are the components of the cardiovascular system?
Heart and blood vessels
What are the two branches of the cardiovascular system?
- pulmonary
- systemic
What is the path of blood flow in the pulmonary circuit?
- vena cava
- right atrium
- right ventricle
- pulmonary arteries
What is the path of blood flow in the systemic circuit?
- pulmonary veins
- left atrium
- left ventricle
- to body
_____ brings oxygen-poor blood to lungs
Pulmonary circuit
_____ brings oxygen-rich blood to body
Systemic circuit
What is the heart?
- pump
- four chambered
- responsible for blood flow
What are the layers of the heart?
- epicardium
- myocardium
- endocardium
The epicardium is also known as:
Visceral percardium
Endocardium is lined with:
Endothelium (simple squamous epithelium)
____ encloses the pericardial cavity which contains pericardial fluid
Pericardium
What is the pericardium?
Double walled pericardial sac with a serous and fibrous layer
What is the function of the peridardium?
Allows the heart to slip and slide around as it is beating
Epicardium aka:
visceral layer of the serous pericardium
The epicardium is lined with _____ called ______
Simple squamous epithelium; mesothelium
Epicardium contains:
- Loose connective tissue that contains coronary vessels, nerves, ganglia
- adipose tissue
Thickest of the three layers
Myocardium
Myocardium is composed of:
Cardiac muscle
Myocardium contains muscle cells such as:
- Sinoatrial node
- atrioventricular node
- Atrioventricular bundle (bundle of His)
- purkinje fibers
- ANP cells (specialized cells that secreted ANP)
What is the function of the SA node?
- pacemaker of the heart
- sets pumping rate
Where is the SA node located?
Junction superior vena cava, right atrium
What is the function of the AV node?
accepts impulses from SA node
Where is the AV node located?
Medial wall of right ventricle
Bundle of His serves ____
Both ventricles
What are purkinje fibers?
branches of the bundle of His
What is ANP?
Atrial Natriuretic Peptide
ANP is primarily produced by:
Cells of the auricles of the atria
What is the function of ANP?
- Promotes salt and water excretion by the kidneys
- lowers blood pressure
The effects of ANP are antagonistic to _____
Aldosterone
What is the endocardium?
Innermost layer of the heart
Endocardium is lined by ____ which is termed _____
simple squamous epithelium; endothelium
Where is the subendocardial layer found?
Between the endocardium and myocardium
What does the subendocardial layer contain?
- fibroelastic connective tissue
- small blood vessels
- nerves
- purkinje fibers
Arteries carry blood _____
Away from the heart
Types of arteries
- elastic
- muscular
- arterioles
- metarterioles
____ are conducting or large arteries
Elastic
____ are distributing or medium arteries
Muscular
Functions of arterioles
- regulate blood pressure
- vasoconstrict or vasodilate
- distribute blood to capillaries
Veins carry blood _____
Away from body tissues, toward the heart
Types of veins
Small, medium, large
Small veins are termed:
Venules
What is the function of venules?
- exchange of material
- respond to vasodilators (serotonin, histamine)
Do capillaries contain smooth muscle?
No - no vasomotor
Types of capillaries
- fenestrated
- continuous
- discontinuous
Blood vessels have a constant design, consisting of:
3 tunics (tunica intima, tunica media, tunica adventitia)
Tunica intima is lined with:
Endothelium (simple squamous epithelium)
Tunica intima contains what components?
- endothelium
- subendothelium (connective tissue)
- internal elastic lamina
Tunica media contains:
- muscle and/or elastic fibers
- connective tissue
- external elastic lamina
Tunica adventitia contains:
- primarily connective tissue
- scattered muscle fibers, vasa vasorum, nerve fibers
Blood vessels contain a general structure. What makes arteries and veins different?
Size of each tunic
_____ have an incomplete internal elastic lamina
Elastic arteries
_____ contain 40-70 fenestrated elastic membranes
Elastic arteries
_____ contain ~40 layers of smooth muscle cells
Muscular arteries
Arterioles contain ____ layers of smooth muscle cells
1-2
In metarterioles, ____ are formed by _____ of smooth muscle cells. These encircle _____
Precapillary sphincters; incomplete rings; origins of the capillaries
As blood moves through larger to smaller arteries, the tunica media gets:
Thinner and thinner
What are metarterioles?
Terminal ends of the arterioles
Endothelial cell functions (8)
- barrier function (selectively permeable membrane)
- vasoconstriction and vasodilation
- inhibition of coagulation
- facilitation of transepithelial migration of inflammatory cells
- angiogenesis
- synthesis of growth factors
- modifying angiotensin I
- oxidation of lipoproteins
Endothelin I is secreted by _____ and attaches to _____
Capillary endothelial cells; vascular smooth muscle cells
What is endothelin I?
potent vasoconstrictor; keeps smooth muscle cells contracted for long periods of time resulting in elevated blood pressure
Some _____ cells contain Weibel-Palade bodies, meaning they contain _____
Endothelial; von Willebrand factor
Function of von Willebrand factor
- Facilitates coagulation of platelets
- mediates adhesion of platelets to damaged epithelial surfaces
____ mediated adhesion of platelets to damaged epithelial surfaces
von Willebrand factor
Von Willebrand disease is ____
Inherited
Describe symptoms of Von Willebrand disease
- impaired platelet adhesion
- prolonged coagulation time
- excessive bleeding
____, especially _____, are responsible for exchange of materials
Venules; postcapillary venules
Venules contain _____ instead of a tunica media
Pericytes
______ act on small venules
Serotonin and histamine
What is the effect of serotonin and histamine on small venules?
Makes them leaky by increasing the distances between membranes of contiguous endothelial cells
Most intracellular gaps occur in _____ venules rather than in capillaries
Postcapillary
Leukocytes leave the vascular system at the _____ to enter the connective tissue space via diapedesis
Postcapillary venules
pass through intercellular junctions of endothelial cells
What are pericytes?
Contractile cells that wrap around the endothelial cells that line capillaries and venules
Pericytes have some ____ properties
Contractile
Capillary types
- Continuous
- Fenestrated
- Sinusoidal (discontinuous)
____ capillaries have the smallest diameter and form tight junctions
Continuous capillaries
_____ have an intermediate diameter and form tight junctions
Fenestrated capillaries
_____ have the largest diameter and have discontinuous endothelium and basal lamina
Sinusoidal capillaries
_____ can pass through the fenestrations of fenestrated capillaries
Larger molecules
_____ and _____ have the ability to alter cappilary permeability
Bradykinin and histamine
Capillary permeability is dependent on:
- type of endothelial cell
- size, charge, shape of traversing substance
Capillary permeability allows for:
- diffusion
- active transport
- movement through fenestrae or through gaps in the intercellular junctions
Where are continuous capillaries found?
- muscle
- thymus
- nervous and connective tissues
What moves across the continuous capillary wall?
- amino acids
- glucose
- nucleosides
- purines
Continuous capillaries are characterized by:
abundance of pinocytotic vesicles
What is diapedesis?
Passage of blood cells, especially leukocytes, through the unruptured walls of capillaries (and small venules) into tissue
_____ is one of the first inflammatory responses to infection
Diapedesis
During diapedesis, molecules pass through the areas of the ____ which have _____ in response to the infectious process
Tight junctions; loosened
Fenestrated capillaries are characterized by _____
Pores in their walls that are covered by a pore diaphragm
Fenestrated capillaries allow ______ compared to the continuous capillary
More to travel across the wall
Where are fenestrated capillaries found?
Pancreas, intestines, endocrine glands
______ have discontinuous endothelial cells and basal lamina
Sinusoidal/discontinuous capillaries
Sinusoidal capillaries contain:
Large fenestrae without diaphragms
Where are sinusoidal capillaries found?
- bone marrow
- liver
- spleen
- some of the endocrine glands
Sinusoidal capillaries have an _____ diameter
Enlarged
____ are often located either in or along the outside of the endothelial wall of sinusoidal capillaries
Macrophages