Histology

Question 1

what are the roles of the cardiovascular system

Answer 1

Transport of oxygen and nutrients to the tissues.

Transport of CO2 and other metabolic waste from the tissues.

Temperature regulation.

Distribution of hormones and immune cells.

Reproductive function in males: penile erection.

Question 2

what are the three layers of blood vessels

Answer 2

inner = tunica intima, middile = tunica media, 
outer = tunica adventitia

Question 3

describe the tunica intima

Answer 3

single layer of squamous epithelial cells (endothelial) supported by a basal lamina and thin layer of connective tissue

Question 4

what is a basal lamina

Answer 4

extracellular matrix on which epithelial sits (basement membrane)

Question 5

describe the tunica media

Answer 5

predominantly smooth muscles, thickness varies

Question 6

describe the tunica adventitia

Answer 6

supportive connecting tissue

Question 7

what separates the tunica intima and the tunica media

Answer 7

layer of elastuc tissue called the internal elastic membrane

Question 8

what separates the tunica media and the tunica adventitia

Answer 8

external elastic membrane

Question 9

what are elastic arteries

Answer 9

largest arteries (e.g. aorta) as have many sheets of elastic fibres in their tunica media to provide elastic recoil

Question 10

what does the recoil elastic arteries maintain

Answer 10

diastolic blood pressure

Question 11

what are vasa vasorum

Answer 11

vessels of the vessel- supply nutrients to outpart of vessel that cannot obtain nutrients from the lumen

Question 12

what is a lumen

Answer 12

inside of tubular structure

Question 13

what happens to the composition of arteries as they become smaller

Answer 13

loose layers of smooth muscles

Question 14

describe the composition of arterioles

Answer 14

one or two layers of smooth muscle in their tunica media with almost no tunica adventitia

Question 15

describe the composition of capillaries

Answer 15

endothelial cells and a basal lamina (diameter of 4-8 micrometers)

Question 16

what are pericytes

Answer 16

connective tissue with contractile properties local at intervals out basal lamina of capillaries

Question 17

what are the three types of capillaries

Answer 17

continuous, fenestrated, sinusoidal/discontinuous

Question 18

describe continuous capillaries

Answer 18

most common- found in muscle, connective tissue, lung, skin and nerves

Question 19

describe fenestrated capillaries

Answer 19

have approx 50nm pore in wall. found in mucosa of the gut, endocrine glands, glomeruli of the kidney

Question 20

describe sinusoidal or discontinuous capillaries

Answer 20

lack a basal lamina and have large gaps. found in liver, spleen and bone marrow

Question 21

what is microvasculature

Answer 21

Small arterioles connect to a postcapillary venule through a network made up of metarterioles, thoroughfare channels and capillaries.

Question 22

what are precapillary sphincters

Answer 22

smooth muscle rings at the beginning of the capillary to help control flow through the network

Question 23

where do capillary networks drain into

Answer 23

post capillary venules

Question 24

describe post capillary venules

Answer 24

endothelial cell-lined and contain a thin layer of connective tissue and occasional pericytes

Question 25

what happens at post capillary venules

Answer 25

important sites for exchange

Question 26

when do post capillaries venules become 'venules'

Answer 26

once vessel begin to acquire intermittent smooth muscle cells in a tunica media layer

Question 27

describe the tunica adventitia of the largest veins

Answer 27

thick with incorporated bundles of longitudinally oriented smooth muscle

Question 28

why do veins contain most of the blood in the body

Answer 28

as are flexible and can accommodate the expansion

Question 29

what are the valves in veins made of

Answer 29

inward extensions of the tunica intima

Question 30

how do you histologically differentiate an artery and vein

Answer 30

thickness of tunica media artery thick

Question 31

what are the three layers of the heart

Answer 31

endocardium (inner), myocardium (middle), epicardium (outer)

Question 32

what are the two layers of the serous pericardium

Answer 32

visceral and parietal

Question 33

what are the layers surrounding the epicardium

Answer 33

epicardium-visceral layer of serous pericardium- | pericardial cavity- parietal layer of serous pericardium- fibrous pericardium- adipose tissue

Question 34

what does endoCARDIUM line

Answer 34

entire inner surface of the heart including the valves

Question 35

describe the structure of the endocardium

Answer 35

endothelium, basal lamina, thin layer of collagen fibres, layer of denser connective tissue

Question 36

what is a subendocardium

Answer 36

in some areas of heart- loose connective tissue containing small blood vessels and nerves and the branches of the impulse conducting system.

Question 37

what is backing the endothelial layer of the endocardium

Answer 37

fibrous tissue

Question 38

describe the structure of the myocardium

Answer 38

thick middle layer, bundles and layers of contractile cardiac muscle fibres, individual muscle fibres are surrounded by delicate, collagenous connective tissue with a rich network of capillaries (cardiac muscle cells in connective matrix)

Question 39

describe the myocardium structure

Answer 39

single central nucleus cardiac muscle cells. intercalated discs passing across the fibres at regular intervals

Question 40

what is the purpose of the intercalated discs passing across the muscle fibres in the myocardium

Answer 40

acts to attach cells but allows spread of electrical activity- creates extensive network that stops intracellular junction ripping apart when the cells contract

Question 41

what allows the spread of electrical activity between cells

Answer 41

gap junctions

Question 42

describe the epicardium

Answer 42

on the surface of the heart a single layer of flattened epithelium called mesothelium basal lamina fibroelastic connective tissue and (in some places) adipose tissue

Question 43

where are the coronary arteries and what does their placement allow

Answer 43

on surface in adipose tissue (under connective tissue and mesothelium) allows easy access- bypass

Question 44

what is the mesothelium

Answer 44

the simple squamous epithelium that lines the pleurae, peritoneum, and pericardium

Question 45

describe the fibrous pericardium

Answer 45

sac of tough fibrocollagenous connective tissue

Question 46

describe the serous pericardium

Answer 46

layer of simple squamous epithelium (mesothelium), backed by a basal lamina and connective tissue

Question 47

what does the serous pericardium line

Answer 47

the inner surface of the fibrous pericardium (parietal) and covers the surface of the heart (visceral)

Question 48

what separates the two mesothelial layers of the serous pericardium

Answer 48

pericardial cavity which contains a small amount of pericardial fluid

Question 49

describe the fibrous skeleton of the heart

Answer 49

formed by thick bands of fibrous connective tissue around the heart valves between the atria and ventricles

Question 50

what is the role of the fibrous skeleton of the heart

Answer 50

supports the valves, but also provides the attachments for the cardiac muscle fibres and acts as electrical isolator between atria and ventricles

Question 51

are there blood vessels in the heart valves

Answer 51

no

Question 52

describe the structure of the heart valves

Answer 52

Have an outer endothelial layer with basal lamina. Layer of collagen and elastin fibres. A core of dense connective tissue, called the lamina fibrosa, that is in continuity with the fibrous skeleton. The leaflets of the valves separating the atria from the ventricles (the mitral and tricuspid) are anchored to papillary muscles in the wall of the ventricle by collagenous strands called the chordae tendineae, which merge with the lamina fibrosa.

Question 53

describe the lamina fibrosa

Answer 53

the core of a heart valve and is dense irregular connective tissue that is continuous with the fibrous skeleton of the heart.

Question 54

what covers the heart valve on both sides

Answer 54

endothelium

Question 55

what are the three types of cardiac muscle cell

Answer 55

contractile, pacemaker and conducting

Question 56

describe pacemaker cells

Answer 56

pale because of organelles within them embedded in extensive matrix of connective tissue fer myofibrils, little glycogen

Question 57

how does electrical signals travel through the skeleton

Answer 57

tunnel in skeleton for AV bundle

Question 58

describe purkinje cells

Answer 58

larger than normal cells, They have, abundant glycogen, no T-tubules, no intercalated discs and sparse actin and myosin filaments, which tend to be found at the periphery of the cells. found in the subendocardial layer just deep to the endocardium, they appear pale, and often exhibit a very pale/clear centre.

Question 59

where in the body are lymphatic vessels missing

Answer 59

brain and bone

Question 60

what is the role of the lymph system

Answer 60

system of relatively thin walled vessels that drain excess interstitial fluid (lymph) into the blood stream

Question 61

what is the role of lymph nodes

Answer 61

immunological surveilance

Question 62

describe lymphatic vessels

Answer 62

no central pump, but smooth muscle in walls, hydrostatic pressure in the tissue and compression of the vessels by voluntary muscle, combined with valves in the vessels, produces flow.