Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
56 Cards in this Set
- Front
- Back
|
What is the systemic system?
|
(a high pressure system), from the heart to the tissues and back.
|
|
|
What is the pulmonary system?
|
(a low pressure system), from the heart to the lungs and back.
|
|
|
Describe the tunica intima
|
Consists of a layer of endothelial cells resting on a basal lamina; a subendothelial layer, consisting mostly of connective tissue.
|
|
|
Describe the tunica media
|
Consists chiefly of concentric layers of circularly arranged smooth muscle . Collagen is also present. Media is separated from the intima by internal elastic lamina( composed of elastic fibers in a nonfibrillar form- elastin). most medium-sized/ larger arteries have external elastic lamina between the media tunica adventitia.
|
|
|
What do smooth muscle cells produce in tunica media?
|
These smooth muscle cells produce elastic and reticular (Type III collagen) fibers and proteoglycans.
|
|
|
What is fxn of fenestrae in lamina of tunica media
|
This lamina has gaps or fenestrae (Latin = windows) which allows for diffusion of substances.
|
|
|
Describe the Tunica adventitia
|
Consists mainly of longitudinally oriented collagen (Type 1)
and elastic fibers. The adventitia layer becomes continuous with enveloping connective tissue (fascia). |
|
|
What are blood vessels and nerves called in tunica adventia
|
Blood vessels to the vessel (vasa vasorum) and nerves to the vessel (nervi vasorum) can be found in this layer.
|
|
|
describe sympathetic nerve fibers
|
Most blood vessels that contain smooth muscle supplied with network of unmyelinated sympathetic nerve fibers (vasomotor nerves).
|
|
|
How does the neurotransmitter neuroepinephrine effect these nerve fibers?
|
causes vasoconstriction in most vascular beds and diffuses through the media, its effect propagated by gap junctions between the cells
|
|
|
What are common sites for baroceptors?
|
carotid sinus and arch of aorta--for pressure
|
|
|
What are common sites for chemoceptors?
|
carotid and aortic bodies
|
|
|
Describe structure of capillaries
|
composed of single layer of endothelial cells rolled in the form of a tube. When cut transversely, the capillary walls are observed to consist of portions of one or more cells. External surface of these cells rest on a basal lamina, a product of the endothelial cell.
|
|
|
What are typical organelles in endothelial cells?
|
abundant vimentin intermediate filaments ( mesenchymal origin) and numerous microfilaments which explains the endothelial cells' contractile properties.
|
|
|
What links endothelial cells together?
|
Zonula occludens, an occasional desmosome and gap junctions link the cells.
|
|
|
What are 4 types of capillaries?
|
Continuous or somatic ; Fenestrated or visceral ; Fenestrated with no diaphragms; Sinusoidal
|
|
|
Describe Continuous or somatic capillaries
|
absence of fenestrae in its wall---found in all kinds of muscle tissue, CT, exocrine glands and nervous tissue. Numerous pinocytotic vesicles are present on both surfaces of muscle capillaries. Complete basal lamina.
|
|
|
What do you know about Fenestrated or visceral capillaries?
|
large fenestrae in walls of endothelial cells. Fenestrae are closed by a diaphragm that is thinner than a cell membrane. continuous basal lamina present. Rapid interchange of substances occurs where these are located: kidney, intestine, endocrine glands, choroid plexus.
|
|
|
Describe Fenestrated with no diaphragms type of capillaries
|
fenestrated capillary but no diaphragms close the openings--has thick basal lamina and characteristic of the renal glomerulus
|
|
|
What does Dr. Meek say about Sinusoidal capillaries?
|
large diameter which slows the
circulation of blood and intercellular and transcellular holes (much larger than fenestrae). Basal lamina almost entirely absent, its traces may be seen in some places. found in liver, spleen, bone marrow, adrenal cortex, adenohypophysis. It is called a discontinuous capillary. Macrophages are located either among or outside the cells of the endothelium. |
|
|
What is sequence of microcirculation?
|
general arrangement of capillaries is between arteries and veins. arteriole → metarteriole → capillary → venule and vein.
|
|
|
What are arteriovenous anastomoses?
|
direct routes which divert blood from capillaries
Capillary circulation is controlled by neural and hormonal stimulation. |
|
|
What is the metarteriole?
|
Arterioles can branch into smaller vessels with a discontinuous layer of smooth muscle, the metarteriole.
|
|
|
Where are precapillary spinchters present?
|
where capillaries originate from the metarteriole, so blood may be diverted from a network.
|
|
|
How is capillary stimulation controlled?
|
by neural and hormonal stimulation.
|
|
|
Capillaries can function as exchange vessels and transfer....
|
oxygen, carbon dioxide, and metabolites are transferred from blood to tissue and tissues to blood.
|
|
|
Where can permeabilty of capillaries can be altered?
|
at the cell junction, fenestrae, pinocytotic vesicles (ex. muscle, nerve) or holes in the endothelium.
|
|
|
How can permeabilty be altered in capillaries?
|
by pharmacologically active substances (histamine and bradykinin.) Occlusion can be so tight that passage of macromolecules is not permitted (blood-brain barrier, blood-thymus barrier, blood-testicular-seminiferous--- primary occluder is the tight junction)
|
|
|
How are endothelial cells involved in metabolis?
|
(1) conversion of angiotensin to angiotensin II; (2) conversion of bradykinin,prostaglandins, etc. to inert compounds; (3) breakdown lipoproteins (lipolysis).
|
|
|
What is the Antithrombogenic function of capillaries?
|
endothelial cells prevent contact of platelets with subendothelial connective tissue.
|
|
|
What do arteries do?
|
transport blood to tissues ---resist changes in blood pressure in their initial portions and regulate blood flow in their terminal portions.
|
|
|
How are arteries distinguished from one another?
|
on basis of thickness and differences in composition of tunics, especially the tunica media.
|
|
|
What are examples of elastic arteries?
|
include the aorta and its large branches
|
|
|
Describe the intima layer of elastic arteries?
|
Relatively thick (thicker than t.i. in a muscular artery). subendothelial layer is thick and contains connective tissue (collagen, elastic and reticular fibers) Main cell type is smooth muscle. An internal elastic lamina is present but may not be evident, since is similar to the elastic lamina in the next layer
|
|
|
Describe the media layer
|
thickest of three tunics. Consists of concentric rings of perforated elastic lamina with smooth muscle cells, collagen fibers, reticular fibers, and ground substance between. No fibroblasts--- smooth muscle cells secrete the above fibers and g.s.
|
|
|
What is the tunica adventia in elastic arteries composed of?
|
thin connective tissue layer containing mainly collagen fibers to prevent further expansion during systole (ventricular contraction). External elastic lamina is indistinguishable.
|
|
|
What does external lamina layer in tunica adventitia contain?
|
blood vessels (vasa vasorum) and nerves (nervi vascularis). The vasa vasorum supplies the outer wall, the inner wall is supplied from the lumen of the vessel.
|
|
|
What about muscular arteries...
|
most of the named arteries in the body ---includes a range from small to medium-sized muscular arteries.
|
|
|
What is tunica intima layer of muscular arteries composed of?
|
Typical but with a thin subendothelial layer. Internal elastic lamina could be prominent and is undulating or wavy due to contraction of smooth muscle.
|
|
|
What about the tunica media of musclcular arteries?
|
up to 40 layers of smooth muscle cells arranged in a concentric or spiral fashion around the wall. Elastic lamellae can be present as well as reticular fibers and g.s. External elastic lamina is usually present.
|
|
|
The tunica adventia in muscular layer consists of...
|
CT layer is about as thick as media and consists of collagen, reticular, elastic fibers, fibroblasts, adipose cells, lymphatics, vaso vasorum, and nervi vascularis.
|
|
|
What is function of arterioles?
|
these vessels are the stopcocks of capillaries
|
|
|
Describe three layers of arteioles
|
Intima: typical with thin subendothelial layer. I.E.L. may be present, usually in larger arterioles.
Media: 1-4 layers of s.m. T.A.-thin and ill-defined. |
|
|
Weibel-Palade granules in endothelial celss contain
|
coagulation factor VIII, von Willebrand's factor.
|
|
|
What is molecule involved in maintenance of nonthrombogenic barrier and secretion of anticoagulants in endothelial cells?
|
thrombomodulin
|
|
|
What is ACE and its functions according to Dr. Meek?
|
angiotensin-converting enzyme involved in modulation of blood flow by secretion of vasooonstrictors
|
|
|
What does EDRF stand for and what does it do?
|
endothelial-derivede relaxation factor and functions as a vasodialtor
|
|
|
What is another vasodialator associated with endothelial cells?
|
NO (Nitric Oxide)
|
|
|
What do we need to know about hemopoietic colony-stimulating growth factors GN-CSF, G-CSF, M-CSF
|
regulate cell growth and secrete growht stimulating factors
|
|
|
What about heparin and endothelial cells?
|
secretion of growth inhibiting factors
|
|
|
What is function of LDL' in relationship to endothelial cells?
|
involved in lipid metabolism and production of free radicals
|
|
|
What is the function of veins?
|
return blood to heart -- aided by smooth muscle and valves. At any one time 70% of the blood is in these vessels.
|
|
|
What are effects of bradykinin on capillaries?
|
Bradykinin is a nonapeptide that causes blood vessels to enlarge (dilate), and therefore causes blood pressure to lower. A class of drugs called ACE inhibitors, which are used to lower blood pressure, increase bradykinin (by inhibiting its degradation) further lowering blood pressure. Bradykinin works on blood vessels through the release of prostacyclin, nitric oxide, and Endothelium-Derived Hyperpolarizing Factor.
|
|
|
How does histamine affect capillaries?
|
increases the permeability of the capillaries to white blood cells and other proteins, in order to allow them to engage foreign invaders in the affected tissues.[
|
|
|
How is angiotensin 1 change to angiotensin 2?
|
Angiotensin I is converted to angiotensin II through removal of two terminal residues by the enzyme Angiotensin-converting enzyme (ACE, or kinase), which is found predominantly in the capillaries of the lung.
|
|
|
What is clinical significance of angiotensin 1 changing to angiotensin 2?
|
ACE is a target for inactivation by ACE inhibitor drugs, which decrease the rate of angiotensin II production. Angiotensin II increases blood pressure by stimulating the Gq protein in vascular smooth muscle cells (which in turn activates contraction by an IP3-dependent mechanism).
|
