diversity of cells and their functions

Question 1

histological techniques

Answer 1

a chemical that cross links proteins such as formalin is used to preserve the tissue
tissue has to be thinly sliced to preserve the tissue

Question 2

Dyes

Answer 2

the most common dye used is a combination of haematoxylin and eosin.

Question 3

haematoxylin

Answer 3

a basic dye that has an affinity for acidic molecules and stains them purple/blue- for example DNA or the nucleus

Question 4

eosin

Answer 4

an acidic dye that has affinity for basic molecules and stains them pinkish red. most proteins in the cytoplasm are basic and as a result the cytoplasm is often stained pink or red.

Question 5

tissue types

Answer 5

there are 4 basic tissue types- epithelial, connective, muscle and nervous

Question 6

epithelium

Answer 6

cover the surface of the body, line hollow organs and also form glands. they occur as sheets of cells and vary widely in shape, size, orientation and function

Question 7

connective

Answer 7

forms the framework of the body, but beyond that it has a dynamic role in the development, growth and homeostasis of tissues, and via fat, in energy storage

Question 8

muscle

Answer 8

specialised to generate force by contracting

Question 9

nervous

Answer 9

nervous tissue consists of neurons and their supporting cells. nervous tissue serves a control function and allows for rapid communication between different parts of the body

Question 10

epithelia (in detail)

Answer 10

adhesion between epithelia cells is strong, thus forming sheets of cells. this is good for lining body cavities.
all have a layer of extracellular matrix components called basel lamina (basement membrane) to which cells are attached
all are non-vascularised

Question 11

functions of epithelia

Answer 11

mechanical barrier (skin)
chemical barrier (stomach lining)
absoption (lining of intestine)
secretion (salivary gland)
containment (lining of urinary bladder)

Question 12

classification of epithelia

Answer 12

shape- squamous (flattened like a fish scale)

       - cuboidal (cube shaped)
       - columnar (like a column)

number of layers- simple (one layer)

                         - stratified (2 or more layers)
                         - pseudostratified ( appears to have multiple layers but all tissue is in contact with the basal lamina)

Question 13

epithelial glands

Answer 13

endochrine glands- product secreted towards the basal end of the cell, then distributed by the vascular system

exochrine glands- product secreted towards the apical end of the cell either into the lumen of an internal space or body surface

Question 14

connective tissue

Answer 14

soft connective tissue- tendons, ligaments, mesentary, stroma of organs dermis of the skin etc.

hard connective tissue- bone and cartaledge

blood and lymph- specialised form of connective tissue

Question 15

connective tissue- extracellular matrix

Answer 15

consists of- fibres: collagen, reticular and elastic fibres

               - ground substance: GAGs, most of which are bound to protein cores to form glycoproteins
                 - tissue fluid

Question 16

cells

Answer 16

Fibroblasts: widely distributed cells that produce and maintain the extracellular matrix
adipose cells: fat cells
osteocytes: cells of bone
Chondrocytes: Cells of cartilidge

Question 17

cartilage

Answer 17

strong, flexible, compressible, semi rigid tissue
avascular
three types, defined by the extracellular matrix: hyaline, elastic and fibrocartilage

Question 18

bone

Answer 18

an outer shell of dense cortical bone makes up the shaft

cancellous or trabecular bone occupies the end of the bone

Question 19

muscle

Answer 19

3 main types: smooth, cardiac and skeletal

Question 20

smooth muscle

Answer 20

called smooth because it has no visible striations

involuntary because it isnt under conscious control and visceral because its predominantly found in organs

Question 21

skeletal muscle

Answer 21

constitutes the muscle of the body that respond to conscious control
multinucleated, cylindrical cell

Question 22

cardiac muscle

Answer 22

forms the major part of the walls of the heart chambers and origins of the great vessels
fibres are much shorter than striated muscle

Question 23

nervous tissue

Answer 23

consists of neurons and support cells (glia)

surrounded by connective tissue coat- meninges for central nervous system and epineurium for peripheral nervous system

Question 24

principle glia of the CNS

Answer 24

astrocytes: support, ion transfer, induce brain blood barrier
Oligondenrocytes: produce mylin in the brain and spinal chord
microglia: provide immune surveillence

Question 25

principle glia of the PNS

Answer 25

schwann cells: produce myelin and support axons