Shared Flashcard Set

Details

Cardiovascular: Vessels & Circulation
Vessels and Circulation
45
Anatomy
Undergraduate 3
03/21/2016

Additional Anatomy Flashcards

 


 

Cards

Term
Efferent
Definition
Arteries carry blood away from the heart
Term
Afferent
Definition
Veins return blood from capillaries to the heart
Term
Capillaries
Definition
microscopic vessels where exchange of gases and solutes occurs between the blood and tissues.
Term
Tunics
Definition

--Blood vessel layers

--any vessel that has a wall w/ 3 layers

 

Term
lumen
Definition

--cavity

--inside space of the vessel

Term
tunica interna
Definition
Includes the endothelial lining and an underlying layer of loose connective tissue.
Term
tunica media
Definition
Contains circular sheets of smooth muscle tissue in a framework of loose connective tissue.
Term
Tunica Externa
Definition

--Outermost layer.  Forms a connective tissue covering around the vessel.

--The connective tissue here tends to blend with neighboring tissues.  This stabilizes and anchors the vessel.


Term
vaso vasorum
Definition

 

---network of small arteries in the tunica externa.

--the blood supply of a blood vessel

Term
Elastic Arteries or Conducting Arteries
Definition

**large vessels with a diameter from 1 cm to 2.5 cm.  Ex: Pulmonary artery and aorta.

 

a. Transport large volumes of blood from the heart. 

 

b. During ventricular systole, blood is ejected into elastic arteries and they expand.  During ventricular diastole, elastic arteries recoil (because of their elasticity) and return to their original size.

 c. The expansion of elastic arteries cushions the sudden rise in blood pressure during ventricular systole and their recoil slows the drop in pressure during ventricular diastole

d. This allows blood flow within the arteries to be continuous even though blood flow from the heart is discontinuous.

 

 

Term
Muscular Arteries or Distributing Arteries
Definition

--Bring blood to all areas of the body

--Distributes blood to the body's skeletal muscle and organs.  Ex: external carotid arteries of neck, brachial arteries of arm and femoral arteries of thigh.

Term
Arterioles
Definition

--Very small, microscopic

--internal diameter of 30m m or less.  The tunica media consists of six or less layers of smooth muscle.  The smallest ones do not have a tunica externa.

Term
Vasomotor tone
Definition

Smooth muscle of arterioles is usually partially constricted. 

--always somewhat toned

Term
Capillaries
Definition

--exchange vessels, slow flow of blood

--blood vessels that allow for the exchange of nutrients and gases to the interstitial fluids due to tissue anatomy; blood flows at a slow velocity through them.  They connect the arteries to the veins.  Millions of them are found in the body.

Term
Structure of the capillary
Definition
one layer thick of endothelial cells lying on a basement membrane (holds epithelial cells together and to surrounding tissue; composed of fine fibers of collagen; connects it to tissues it's sitting near).  Average diameter is 7.5 mm (close to the size of an RBC).
Term
Continuous Capillary
Definition

--capillary lining is complete.  Materials can move in and out of the blood through endothelial cells (diffusion, pinocytosis) or between cells through intercellular gaps, which prevent the movement of large substances from the plasma.  Most common type of capillary. Can be found in skeletal muscle.             

--no openings or gaps, complete

Term
Fenestrated Capillary
Definition

--capillaries with small pores within endothelial cells.  The pores allow for rapid exchange of water and solutes (even small proteins).  Located in areas in need of rapid exchange.  Pinocytotic transport is also present.  Can be found in endocrine glands (release and rapid diffusion of hormones) and within the kidney (for rapid filtration of blood).

--pourous, lots of openings or gaps, like a collander

--promotes transport of materials-- H2O, small proteins

--Found where you need to move products more quickly

Term
Sinusoids or discontinuous capillaries
Definition

--not typical

--wide-open, flattened specialized fenestrated capillaries.   Allows for the free exchange of water, solutes, large proteins and formed elements. Blood moves through sinusoids slowly.  This allows for absorption and secretion into and out of capillaries.  Can be found in the liver, spleen and bone marrow.

Term
Pre-capillary sphincter
Definition

--allow us to regulate which capillaries are open

--smooth muscle encircling an opening; contract to close; relax to open

Term
Postcapillary venule
Definition
distal segment of the metarteriole.  Connects the metarteriole that then drains blood from the capillary bed.
Term
venules
Definition

--simplest and smallest vein

--collect blood from capillary beds

--may resemble a capillary

Term
Small & Medium Veins
Definition

--collect blood from venules

--they have a thin tunica media with few smooth muscles

Term
Large Veins
Definition

--not many of them

--Collect blood from medium-sized veins.  All layers present.  Ex: superior vena cava and inferior vena cava.

Term
Valves
Definition

--2 leaflets in veins

--help deal with pressure of gravity--pulls blood toward the feet

1. Structure: folds of the tunica interna

 

2. Function: prevent backflow of blood into the capillary network ; keeps blood flowing in one direction.  In veins, blood pressure is below the force of gravity.  Also important are the skeletal muscle contractions that constrict veins in cycles so that blood will be pushed toward the heart.

 

Term
Blood Distribution @ Rest
Definition

--70% in systemic circulation

--55% in systemic veins

--There is approximately 5 liters of blood w/i the closed circulatory system (including the heart)

Term
Simple pathway (of blood vessels)
Definition
one artery, capillary bed, one vein is associated with an organ or body region
Term
Alternate Pathways
Definition

--Anastomosis

--Arteriovenous shunt

--Portal System

Term
Anastomosis
Definition
Joining together of blood vessels
Term
Arterial anastomosis
Definition
two or more arteries converge to supply the same body region
Term
Venous anastomosis
Definition
two or more veins drain the same body area.
Term
Arteriovenous shunt
Definition
transports blood from an artery directly into a vein
Term
Portal System
Definition

Blood flows through two capillary beds.  Ex: portal system (portal vein delivers blood to another organ before blood returns to the heart – artery, capillary bed, portal vein, capillary bed, vein)

--Can be between 2 arteries or 2 veins

Term
Diffusion
Definition

 

Net movement of molecules from areas of high concentration to areas of low concentration.  This occurs most readily in areas where the concentration gradient is large, the distances involved are small and the substance, ion or molecule is small.

--occurs in capillaries through: cell membranes, intercellular clefts, cell membrane channels, pores of fenestrated capillaries, and openings in sinusoids

 

Term
Vesicular transport
Definition

diffusion of contents through a membrane by pinocytosis

--endocytosis/exocytosis

Term
Bulk Flow
Definition

refers to movement of fluids and their solutes in one direction down a pressure gradient. 

--moving water and what's dissolve in it

Term
Filtration
Definition

the movement by bulk flow through the openings in the capillary (for example: between intercellular clefts or pores of fenestrated capillaries) into the interstitial fluid. 

--movement out of capillary

*hydrostatic pressure

Term
Reabsorption
Definition

the movement by bulk flow from the interstitial fluid through the capillary and into the blood.--still requires a gradient (force)

--movement into capillary

*osmosis

Term
Hydrostatic Pressure
Definition

--causes filtration

--pressure on water

The physical force exerted by a fluid on a structure.  Hydrostatic pressure forces water from a high to low pressure. 

Term
Blood Hydrostatic Pressure (HP b)
Definition
the force exerted per unit area by the blood as it presses against the blood vessel wall. HPb causes filtration from the capillary. 
Term
Interstitial fluid hydrostatic pressure (HP if)
Definition
the force exerted per unit area by the interstitial fluid against the blood vessel wall.  HPif  is almost zero.
Term
Net filtration pressure
Definition

 

the difference between the net hydrostatic pressure and the net colloid osmotic pressure.

 

Term
Net hydrostatic pressure
Definition

 

(HPb – HPif).   

 

                        Arterial end: 35 mmHg – 0 mmHg = 35 mmHg

 

                        Venous end: 16 mmHg – 0 mmHg = 16 mmHg

 

Term
Interstitial fluid colloid osmotic pressure (COPif)
Definition
The osmotic pressure driving water into the interstitial fluids around the capillary from the blood plasma.  This value is about 5 mmHg in most tissue fluids of body since they are nearly protein free.
Term
Net osmotic pressure
Definition

 

the difference between COPb  and COPif. 

 

                        Both arterial and venous end:  26 mmHg – 5 mmHg = 21 mmHg

 

Term
Net Filtration Pressure
Definition
NFP = (HPb – HPif)(COPb – COPif)
Supporting users have an ad free experience!