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Arteries & veins,capillaries, blood pressure
for my quiz on 7/29/09
21
Anatomy
07/28/2009

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Cards

Term
Tunica externa
Definition

-outermost layer of arteries/veins.

-consists of loose connective tissue

-anchors the vessels and provides passage for small nerves, lymphatic vessels, and smaller blood vessels.

-the inner half are nourishd by diffusion from blood in the lumen.

Term
Tunica media
Definition

- the middle layer of arteries/veins.

-thickest

-made of smooth muscle, collagen,sometimes elastic tissue dependingif its a vein or artery

Term
Tunica Interna
Definition

-innermost layer of veins/artery

-exposed to the blood

-made of simple squamous

-provides a smooth inner lining that normally repels platelets and blood cells.

Term
Artery facts
Definition

-constructed to withstand the surges of blood pressure generated by ventricular systole.

-more musculr than veins.

Term
Conducting/elastic artery
Definition
-largest arteries like pulmonary,aorta,and carotid.
Term
Distributing/muscular arteries
Definition

- smaller branches further away from the heart that distribute blood to a specific organ.

-composed of 25 to 40 layers of smooth muscle tissue

-brachial,femoral,and hepatic arteries.

Term
Resistance/small artery
Definition

- composed of a lot of smooth muscle

-arterioles are the smallest of these arteries with only one to three layers of smooth muscle

-primary points at which the body controls the relative amounts of blood directed to various organs.

Term
Vein structure
Definition

-have valves that prevent the back flow of blood.

-primary fxn is to return deoxygenated blood to the heart to get oxygen from the lungs.

Term
Pressure Gradient (way veins return blood to the heart)
Definition

- pressure in vein is much lower than that in arteries.

-it is aslight pressure gradient taht favors movement towards the heart.

-venous return inceases when blood volume increasesand there is vasodilation

Term
Thoratic Respiratory Pump (way veins return blood to the heart)
Definition

- when you inhale you put pressure on/squeeze the inferior vena cava.

-abdominal pressure drops and thoracic pressure drops.

- causes blood to be squeezed up toward the heart

Term
Cardiac Suction (way veins return blood to the heart)
Definition

- during ventricular systole,chorade tendonae pull AV cusps downward.

-this expands artial space.

-sucking blood into the artia from the vena cava.

Term
Skeletal Muscle Pump (way veins return blood to the heart)
Definition

- veins are surrounded by skeletal muscle

-when we contract muscle blood is forced up through the veins towards the heart.

Term
Gravity (way veins return blood to the heart)
Definition
- blood drains back to your heart from your head and neck due to gravity
Term
Capillaries
Definition

- transparent

-one cell layer thick:the tunica interna

-exchanges made easy between blood and tissue cell

Term
Capillary Bed (interweaving network of tiny capillaries)
Definition

Microcirculation: flow of blood from arteriole to a venule,through capillary bed.

Capillary beds two types of vessels:

-Vascular shunt:a vessel that directly connects the arteriole and venule at opposite ends of the bed.

- True capillaries: exchane vessel.

Term
Capillary bed cont.
Definition
precapillary sphincter: cuff of smooth muscle fibers surrounding the root of each true capillary
Term
Blood Pressure
Definition
is the pressure the blood exerts against the inner walls ofthe blood vessels and it is the force that keeps blood circulating continuously even between heart beat.
Term
Blood pressure facts
Definition

- pressure in the large arteries near the heartis higher and continues to drop throughout the pathway of those arteries further away from the heart, and reaches zero or negative pressure at the Vena Cava

 

Term
Measuring Blood Pressure
Definition
-what we messure is the alternate contraction and relaxation, therefore the on and off flow of blood int the arteries; the systolic and diastolic pressure.
Term
Effects of various factors on blood pressure
Definition

Cardiac Output: when CO increases blood pressure increases.

Periphreal Resistance:the amount of friction encountered by the blood as it flows through the blood vessels.

-Temperature:cold causes vasoconstriction, heat causes vasodilation.

-Diet:low salt, low fat, and low cholestrol help prevent high blood pressure.

-Chemicals: Epinephrine increases HR and BP , Nicotine causes vasoconstiction increases BP, Alcohol causes vasodilation decreases BP

 

Term
Kidney's
Definition

-effect blood volumes.

-increased blood pressure causes decreased fluid retention to help lower blood pressure