Human Anatomy And Physiology Ii Lecture Exam 2

Front 1

Artery

Back 1

Blood vessel that conveys blood away from the heart to capillaries

Front 2

Capillary

Back 2

Microscopic, porous blood vessels for the exchange of substance between blood and tissues.
Diameter 8-10um; length 1mm

Consist of an endothelium layer resting on basement membrane

Front 3

Veins

Back 3

Drain blood from the capillaries, transporting it back to the heart

Front 4

Vessel walls are composed of layers called

Back 4

Tunics

Front 5

Lumen

Back 5

Inside space

Front 6

The three blood vessel tunics are

Back 6

tunica intima

tunica media

tunica externa

Front 7

Tunica intima

Back 7

Innermost layer of blood vessel wall.
Composed of endothelium (s.s. epithelium) that faces blood vessel lumen and a thin subendothelial layer (made of areolar C.T.)
Continuous with the endocardium

Smooth

Front 8

Tunica media

Back 8

Middle layer of blood vessel
Composed of layers of smooth muscle supported by elastic fibers. Responsible for vasoconstriction/vasodilation via contraction/relaxation of said muscles.

Front 9

Vasoconstriction/dilation

Back 9

Narrowing/Constricting of the blood vessel lumen

Front 10

Tunica externa

Back 10

outermost layer of B.V.
Composed of areolar C.T. that contains elastic and collagen fibers.
Anchors vessel to other structures.

Large B.V.'s may have vasa vasorum here

Front 11

Vasa vasorum

Back 11

Network of small arteries which supply blood to larger arteries; located in the tunica externa of said vessels.

Front 12

Companion vessels

Back 12

Arteries and veins that supply the same region and tend to be next to one another

Front 13

Describe the differences between an artery and vein re:

1) lumen diameter

2) general wall thickness

3) cross-sectional shape

4) thickest tunic

Back 13

1) arteries have narrower lumen diameters

2) artery walls are thicker

3) arteries retain cross-sectional shape; vein may be oval and tend to flatten/collapse if no blood is in it

4) artery- tunica media; vein- tunica externa

Front 14

Describe the differences between an artery and vein re:

1) elastic and collagen fibers in tunics

2) valves

3) blood pressure range

4) blood flow

Back 14

1) more in artery

2) only in veins

3) arteries have more range (artery 40-100mmHg; vein 0-22 mmHg)

4) artery transports away from heart; veins transport to the heart

Front 15

Describe the blood oxygen levels in veins vs arteries

Back 15

Systemic veins have low O2

Pulmonary veins have high 02

Systemic arteries have high O2

Pulmonary arteries have low O2

Front 16

What is different about the B.V. wall structure of capillaries vs arteries/veins. Why is this so?

Back 16

Capillaries have a tunica interna with only the endothelium and basement membrane (no subendothelial layer). They do not have a tunica media or externa. This makes the exchange of gasses and nutrients easier.

Front 17

Three types of arteries

Back 17

Elastic arteries -> Muscular arteries -> Arterioles

Front 18

Elastic arteries

Back 18

Largest arteries (diameter 2.5-1cm)

"conducting arteries"

Large proportion of elastic fibers (especially in tunica media) makes them good at stretching

Branch into muscular arteries

Ex: Aorta (including brachiocephalic, common carotid, subclavian), Pulmonary trunk, and common iliac arteries.

Front 19

Muscular arteries

Back 19

Medium-sized (diameter: 1cm-0.3mm)

"distributing arteries"

Thicker tunica media makes for higher vasoconstriction ability; less stretchy than elastic arteries

Two sheets of elastic fibers: external elastic lamina and internal elastic lamina line the divide between tunics.

Branch into arterioles

Ex: Most names arteries.

Front 20

Arterioles

Back 20

Smallest arteries (diameter 0.3mm-10um)

Fewer than 6 layers of muscles in tunica media.

Some only have thin layer of endothelium surrounded by a single layer of smooth muscle

Always slightly constricted

Significant role in systemic BP and blood flow directions

Front 21

What is vasomotor tone and by what is it regulated?

Back 21

The slightly constricted state of arterioles which is regulated by the vasomotor center in the brainstem.

Front 22

Atherosclerosis

Back 22

Dz involving the thickening of the tunica intima and narrowing of arterial lumen due to presence of atheroma (atheromatous plaque)

Front 23

Angioplasty

Back 23

Treatment in which a catheter with a balloon is used to place a stent within an artery, pushing down any plaque. Treatment for atherosclerosis.

Front 24

Aneurysm

Back 24

Arterial wall thinning and ballooning out; dangerous because it is easier to rupture.

Front 25

(3) Types of capillaries

Back 25

Continuous, Fenestrated, Sinusoids

Front 26

Continuous capillary structure and location

Back 26

-Most common capillary

-Continuous endothelium cells which rest on a complete basement membranes

- Intercellular clefts

- Located in muscle, skin, CNS, and lungs

Front 27

Fenestrated capillary structure and location

Back 27

-Complete, continuous endothelium on top of complete basement membrane

- Has pores where endothelium are thin called fenestrations

Front 28

Sinusoid capillaries structure and function

Back 28

-Incomplete lining of endothelium on top of incomplete or absent basement membrane

- Allow formed element/large substance transfer

Front 29

What does a fenestration allow?

Back 29

Passage of smaller plasma proteins but not formed elements.

Front 30

What are intercellular clefts re: capillaries and what do they do?

Back 30

- Spaces bettern endothelium cells in continuous capillary walls (cells connected by tight junctions which do not form seal)

- Allow leukocytes, glucose, A.A, ions, and plasma to pass through; no plasma proteins

Front 31

How must erythrocytes travel in a capillary?

Back 31

In single-file rows called rouleaus

Front 32

What are the ways materials can move into or out of the blood in capillaries?

Back 32

Cellular transport processes:

-pinocytosis (vesicular transport)

-insulin, fatty acids

-diffusion

Through intercellular clefts:

-diffusion and bulk flow

Through fenestrations.

Front 33

Where are fenestrated capillaries found and why?

Back 33

-Small intestine: absorb nutrients

- Ciliary provess: produce aquaeus humor

- Choroid plexus: produce CSF in the brain

- Endocrine glands: permit absorbtion of hormones into the blood

- Kidneys: for filtering blood

Front 34

Where are sinusoid capillaries found and why?

Back 34

- bone marrow: formed elements enter blood

- spleen/liver: erythrocytes phargocytized by macrophages

- endocrine glands

Front 35

What is a capillary bed?

Back 35

Group of capillaries functioning together

Front 36

Trace blood from arteriole, through capillary bed, to venule

Back 36

Arteriole -> metarteriole -> precapillary sphincter -> true capillary -> thoroughfare channel -> postcapillary venule

Front 37

vasomotion

Back 37

Cyclical process of precapillary sphincter contraction/relaxing (5-10per min)

Front 38

How many miles of capillaries?

Back 38

60,000

Front 39

mL of blood in capillaries

Back 39

250-300mL (5% total blood volume)

Front 40

perfusion

Back 40

specific amt of blood entering capillaries per unit of time per gram of tissue (mL/min/g)

Front 41

Small veins

Back 41

venules

Front 42

Vein diameter and special structure

Back 42

>100um

valves - formed by tunica intima

Front 43

Blood distribution at rest

Back 43

Pulmonary circulation - 18%

Heart - 12%

Systemic circulation - 70%

Systemic veins - 55%

Systemic capillaries - 5%

Systemic arteries - 10%

Front 44

End arteries

Back 44

Arteries that provide only one pathway through which blood can reach an organ

Ex. Spleen

Front 45

Anastomosis

Back 45

Joining together of blood vessels (arterial includes 2+ arteries converging to supply blood to one region)

- more likely Venous anastomosis

Front 46

Functional end arteries

Back 46

Arteries with anastomosis that are so small they are basically end arteries

Front 47

Arteriovenous anastomosis

Back 47

- shunt

- transports blood from artery to vein, no capillary bed

- present in finders, toes, pals, ears

- good for conserving heat

Front 48

portal system

Back 48

- blood flows through two capillary bed

- portal vein delivers blood to a second organ prior to returning to heart

- Exe. hyoithalamo-hypophyseal; hepatic

Front 49

What is bulk flow?

Back 49

Movement of large amounts of fluids and dissolved substances in one direction down pressure gradient

Filtration V Reabsorbtion

Front 50

Filtration vs Reabsorbtion (re: capillaries)

Back 50

-Filtration occurs on arterial end; bulk flow out of blood vessel via intercellular clefts and fenestrations

-Reabsorbtion on venous end

Front 51

Bulk flow is dependent upon ...

Back 51

Hydrostatic pressure

Colloid osmotic pressure

Front 52

HPb

Back 52

Blood hydrostatic pressure; pressure exerted by blood against BV wall; promotes filtration

Front 53

HPif

Back 53

Interstitial fluid hydrostatic pressure; interstitial fluid force exerted on external surface of BV; usually close to zero

Front 54

COPb

Back 54

blood colloid osmotic pressure; pull of water back into blood by proteins in blood concentration (like albumin); promotes reabsorbtion

"oncotic pressure"

Front 55

COPif

Back 55

INterstitial fluid colloid osmotic pressure; pull of water back into IF fluid by proteins; relatively low (0-5mmHg)

Front 56

NFP

Back 56

Net filtration pressure; difference between HP and COP; Starling's Law; a positive number indicated filtration; negative indicates reabsorbtion.

Front 57

What is the tendency for HP and COP?

Back 57

HPb is greater on arterial side; HPif is 0 continuously.

COPb and COPif is consistent at both ends

Front 58

How much fluid does capillary typically reabsorb? Where does the excess go?

Back 58

- 85%

- lymphatic system