Histo (04.10) Circulatory System Flashcards
the major function of the circulatory system is to transport why 4 things?
- nutrients
- oxygen
- waste products
- hormones
the left side of the heart pumps for the ____ circuit and receives ____ blood
- systemic
- oxygenated
the right side of the heart pumps for the ___ circuit and receives ___ blood
- pulmonary
- deoxygenated
what 6 things does the heart wall contain
- cardiac muscle
- fibrous skeleton of the heart
- intrinsic conduction system
- coronary vasculature
- a serous membrane
- endothelial cells and underlying connective tissue
the fibrous skeleton of the heart contains what three things?
- four fibrous rings surrounding valve orifices
- two fibrous trigones connecting rings
- membranous portion of inter ventricular and intertribal septa
what are the three layers of the heart wall?
- epicardium
- myocardium
- endocardium
the epicardium is a visceral layer of ____ ___
serous pericardium
the myocardium is composed primarily of the ____ ___ and also contains the ___ ___ of the heart
- cardiac muscle
- fibrous skeleton
what are the three components of the endocardium
- endothelial cells (inner layer)
- dense connective tissue layer
- subendocardial layer (contains the intrinsic conduction system (inner layer))
what are the two atrioventricular valves that prevent back flow into the atria
- tricuspid valve
- bicuspid valve (mitrial valve)
what are the two semilunar valves that prevent back flow into the ventricles
- aortic semilunar valve
- pulmonary semilunar valve
heart valves enforce one way blood through the heart and open/close in response to ___ ___
pressure changes
there are NO valves associated with what three veins into the heart
- venae cavae
- coronary sinus
- pulmonary veins
*pressure is low so no worry about backflow
what are the three layers of the heart valves
- spongiosa
- fibrosa
- ventricularis
layer of the heart valves that is closest to the atrium
spongiosa
layer of the heart valves closest to the ventricle
vetricularis
the spongiosa is loose connective tissue covered in _____ and is loosely arranged ____ and ____ fibers infiltrated with _____ that act as shock absorbers
- endothelium
- collagen
- elastic
- proteoglycans
the fibrosa is the ___ of the valve and contains fibrous extensions from the ____ ____ connective tissue of the ____ rings of the heart
- core
- dense irregular
- skeletal
the ventricularis is ____ connective tissue with layers of ____ fibers covered in endothelium
- dense
- elastic
the cardiac m of the heart is able to ____ and ____ without impulses from the nervous system. its ability to do so is because of the ___ ___ ____ ____
- depolarize
- contract
- intrinsic cardiac conduction system
the intrinsic cardiac conduction system is composed of the 1% NONcontractile cardiac cells called ____ ____ cells as they are self-excitable. they can generate an _____ ____ without nervous system input
- cardiac conducting cells (auto rhythmic)
- action potential
the cardiac conducting cells are organized into ____ and highly specialized conducting fibers/tracts called ____ fibers
- nodes
- purkinje
the cardiac conducting cells are responsible for the initiation and distribution of ____ throughout the heart
impulses
the rate of the intrinsic cardiac m contraction set by the pacemaker cells (cardiac conducting cells) is altered by the sympathetic (____ heart beat) and by the parasympathetic (_____ heart beat) divisions of the autonomic nervous system.
- accelerates
- decelerates
____ can also impact intrinsic rate
hormones
the sinoatrial node is the ___ of the heart that determines the rate through its ___ ____
- pacemaker (happens bc it reaches the threshold fastest)
- sinus rhythm
what are the 5 steps of the excitation sequence that takes place in collections of auto rhythmic cardiac cells
- sinoatrial node
- atrioventricular node
- atrioventricular bundle (bundle of his)
- right/left bundle branches
- purkinje fibers
in reference to the atrioventricular node, impulse travel there via the ____ ___ and impulse is delayed here for ___ to allow for the atria to contract
- internodal pathway (tracts)
- ~0.1s
impulse travels from atrioventricular to the right and left bundle branches; only ___ connection between atria and ventricles; travels across the ____ ____
- electrical
- fibrous skeleton
the branches of the atrioventricular bundle course toward the ___ of the heart through ____ ____
- apex
- interventricular septum
the purkinje fibers (sub endothelial branches) are the ___ pathway in the inter ventricular septum, and head back toward the ____
- finish
- atria
what are the two types of cells in the intrinsic conduction system
- nodal cardiac cells
- purkinje fibers
the nodal cardiac cells are found in the ___ and ___ nodes. they are modified ____ m cells. they are ____ than surrounding atrial contractile cells and contain fewer ____ and lack ____ discs
- SA
- VA
- cardiac
- smaller
- myofibrils
- intercalated
the purkinje fibers are found in what three places
- AV bundle
- bundle branches
- subendothelial branches
the purkinje fibers are modified ___ m cells and are ___ than surrounding ventricular contractile cardiac cells. they contain ___ at the PERIPHERY of the cell. they also have associated ____ discs
- cardiac
- larger
- myofibrils
- intercalated
what are the three layers (tunics) of blood vessels
- tunica interna/intima
- tunica media
- tunica externa/adventitia
what are the three parts of the tunica interna/intima
- endothelium
- basal lamina
- subendothelial layer
layer of blood vessels that contains rings of smooth m cells responsible for vasoconstriction and vasodilatation, can also contain sheets or lamellae or laminae elastin
tunica media
layer of blood vessels that contain vasa vasorum and a nervi vascular is in larger vessels
tunica externa/adventitia
in arteries the thickest layer is the ___ ___
tunica media
in veins the thickest layer is the ___ ___
tunica externa
what are the 4 types of arteries?
- elastic/conducting arteries (large arteries)
- muscular/distributing arteries (medium arteries)
- small arteries
- arterioles
large diameter arteries whose walls contain large amounts of elastic fibers. they are helping to propel blood onward which ventricles are relaxing
elastic/conducitng fibers
medium sized arteries that contain a lot of smooth m. they are important in regulating the blood flow to specific body regions
muscular/distributing arteries
have as many as 8 layers of smooth m in their tunica media
small arteries
smallest artery in diameter and have only 1 or 2 layers of smooth m in the tunica media
arterioles
what is the thickest layer of the elastic or conducting arteries
tunica media
the tunica adventitia of large arteries is ___
thin
the thickest layer of the muscular arteries
tunica media
the tunica adventitia of the muscular artery is relatively ____
thick
the tunica adventitia of both small arteries and arterioles is ____
thin
what are the three layers of capillaries
- continuous
- fenestrated
- discontinuous
continuous capillaries are found in what three places?
- muscle
- lung
- central nervous system
continuous capillaries are uninterrupted endothelial cell lining with ___ or ____ junctions
- tight
- occluding
in continous capillaries you may see ____ ____
pinocytotic vessels (pericytes)
fenestrated capillaries are found where?
- endocrine glands
- sites of fluid and metabolite absorption
the fenestrated capillaries have oval pores called ___
fenestrations
discontinous capillaries (also called ____ ____) are found in what three places?
- -sinusoidal capillaries
- liver
- spleen
- bone marrow
what two characteristics distinguish discontinuous capillaries form all other capillaries?
- larger diameter
- more irregularly shaped
the flow of blood from an arteriole through a capillary network to a post capillary venule is called _____
microcirculation
what three items form a functional unit called the microcirculatory bed or microvascular bed
- arteriole
- capillary network
- postcapillary venule
what are the two types of vessels in the capillary network?
- true capillaries
- arteriovenous (AV) anastomoses or shunts
the more the pre capillary sphincters relax (and the smooth m of the AV shunt _____) the more blood will pass through the ____ ____ in the _____ ____
- CONTRACT
- true capillaries
- capillary beds
the more the pre capillary sphincters contract ( and the smooth m of the AV shunt _____) the more blood will pass through the ____ ___ and ___ the true capillaries
- relax
- ateriovenous anastomoses
- bypass
what are the 4 types of veins
- venule
- small vein
- medium veins
- large veins
smallest type of veins
venules
what are the two types of venues?
- postcapillary venules
- muscular venules
type of venule that has no tunica media and no adventitia. they have endothelial cells with basal lamina and pericytes
postcapillary venule
type of venule that possess a tunica media with one or two layers of smooth m and a thin tunica adventitia and there are typically no pericytes
muscular venule
type of vein that receive blood from muscular venules
small veins
most veins in LIMBS have _____ which prevent ___ of blood
valves
