Histology Final-Circulatory System

Front 1

Describe the cardiovascular system

Back 1

heart and vessels

Front 2

Describe the Lymph Vascular System

Back 2

-begins as blind capillaries in tisssues
-consists of lymphatic vessels
-returns fluid (lymph) to blood via veins at the base of the neck (junction of jugular and subclavian)

Front 3

Describe the Blood Vessel Structure

Back 3

the endothelial wall of areteries and veins have a similar composition plus several additional layers, i.e. tunics: Tunica Intima, Tunica Media, and Tunica Adventitia

Front 4

Describe Blood Vessel Endothelium

Back 4

-a lining consisting of a single layer of endothelial cells that is continuous throughout the system

Front 5

Describe the Tunica Intima

Back 5

-consists of a layer of endothelial cells lining the internal surface
-subendothelial layer of CT
-internal elastic lamina
-present in arteries

Front 6

Describe the Tunica Media

Back 6

-mostly smooth muscle cells and interspersed fibers; Elastic and Reticular with proteoglycans
-external elastic lamina
-present in large arteries

Front 7

Describe the Tunica Adventitia

Back 7

-an outer layer of CT

Front 8

Describe the Vasa Vasorum

Back 8

-the "vessel of vessels"
-nourish the tissue of the arteries and veins

Front 9

Describe Elastic Arteries

Back 9

-large diameter vessels that lead away from the heart and have an abundance of elastic fibers, especially in the Tunica Media

Front 10

Describe Muscular Arteries

Back 10

-distributing arteries
-have more smooth muscle present in the Tunica Media

Front 11

Describe Capillaries

Back 11

-simple endothelial tubes
-average diameter is 7 to 9 um, about the size of a RBC
-form a network of narrow channels
-rate of blood flow through capillaries is much slower than through the arteries, this allows for exchange of materials
-the combined internal diameter of a capillary bed exceeds that of the arteriole supplying it

Front 12

What determines the capillary network structure?

Back 12

the metabolic rate of the tissue determines the closeness of the mesh formed by the capillaries

Front 13

What is the human total capillary surface area?

Back 13

-60 square meters for systemic capillaries
-40 square meters for lung capillaries

Front 14

Describe Capillary Walls

Back 14

-consists of a single layer of flat endothelial cells
-separated from the surrounding CT by a basal lamina
- 2 to 3 and even sometimes only 1 cell makes up the entire circumference of the capillary

Front 15

Describe Pores

Back 15

-transport compartments that are demonstrated physiologically, i.e. functionally
-small pore compartment corresponds to occluding junctions
-large pore compartment corresponds to the transcellular vesicular traffic and to the fenestrae

Front 16

Describe Small Pores

Back 16

-transport compartment corresponding to occluding junctions

Front 17

Describe Large Pores

Back 17

-transport compartment corresponding to the transcellular vesicular traffic and to the fenestrae

Front 18

Describe Capillary Transport

Back 18

-small molecules such as O2 and CO2 are able to diffuse across capillary wall
-other molecules such as glucose move across endothelium by membrane transporters
-additional materials move across the endothelium within a transcellular traffic of membranous vesicles
-some capillaries have fenestrae, i.e. pores through which materials can pass

Front 19

Describe Pinocytotic Vesicles

Back 19

-endothelial cells of most capillaries have numerous pinocytotic vesicles (fluid intake and anything the fluid contains)
-vesicles transport materials across the capillary wall
-vesicles are generally not present in capillaries supplying the nervous system; this is a component of the Blood-Brain Barrier

Front 20

What do capillary subtypes depend on?

Back 20

structure

Front 21

Describe Somatic Capillaries

Back 21

have a continuous endothelium

Front 22

Describe Visceral Capillaries

Back 22

fenestrated; fenestrae are gaps in endothelial wall, like pores, and each is covered by a diaphragm

Front 23

Describe Capillary Diaphragms

Back 23

not hydrophobic; not a cell membrane

Front 24

Describe Glomerular Capillaries

Back 24

fenestrated, but lacking a diaphragm

Front 25

Describe Sinusoidal Capillaries

Back 25

-have an enlarged diameter, 30 to 40 um
-wall may be discontinuous

Front 26

Describe Endothelial Cell Function

Back 26

in addition to exchange of materials:
1. Conversion of biomolecules to active or inactive forms
2. Lipolysis of lipoproteins to release triglycerides and cholesterol for steroid hormone synthesis and membrane synthesis
3. Production of vasoactive factors that affect smooth muscle tone in the wallls of vessels

Front 27

Examples of conversion of biomolecules by endothelial cells

Back 27

-activation of angiotensis I by conversion of angiotensin II
-inactivation of Bradykinin, Serotonin, Prostaglandins, etc

Front 28

Arteriosclerosis Derivation

Back 28

-root word for artery in Greek comes from a word designating large tubular structures in the chest, but not limited to the circulatory system.
-the Latin arterio means artery or windpipe

Front 29

Describe Arteriosclerosis

Back 29

-arteries are flexible, strong, elastic
-elevated blood pressure over time can cause changes in arterial wallas causing them to thicken and become less flexible
-this can restrict the flow of blood to organs and tissues
-hardening of arteries

Front 30

Describe Atherosclerosis

Back 30

-a specific type of arteriosclerosis
-refers to the buildup of calcified fatty deposits on and within artery walls, "plaques"
-these plaques can reduce blood flow by loss of wall flexibility and occulsion of the vessel
-can also burst leading to formation of blood clots

Front 31

What is atherosclerosis caused by?

Back 31

-injury to the endothelial lining of the artery caused by physical and inflammatory stresses
-these processes may promote the deposition of lipoproteins and calcium and lead to the formation of atheroscelrotic plaques

Front 32

Describe endothelial injury from physical stress.

Back 32

-turbulent blood flow, such as what occurs where arteries branch, can cause injury in people who have high blood pressure

Front 33

Describe endothelial injury from inflammatory stress.

Back 33

-any conditions that stimulate inflammatory mechanisms in tissue; chemical abnormalities in the bloodstream and include: infections, high cholesterol, and diabetes complications.

Front 34

Describe lipoproteins

Back 34

macromolecular complexes of protein and lipid in circulation in the blood that can play a role in plaque buildup