tissues

Question 1

define tissue

Answer 1

a group of cells
common embryonic origin
function together to carry out specialised activities

Question 2

three fundamental processes of animal tissue development

Answer 2

1. Cell proliferation
2. Cell specialisation
3. Cell morphogenesis (interaction and movement)

Question 3

name the three primary germ layers

Answer 3

ectoderm
mesoderm
endoderm

Question 4

what kind of tissues do the three germ layers develop into?

Answer 4

ectoderm –> nervous tissue
mesoderm –> all CT, most Muscle tissue
epithelial from all three germ layers

Question 5

define gastrulation

Answer 5

the step where an embryo develops from a 1D layer (the blastula) of epithelial cells to a multidimensional multilayered gastrula (forming mesh/endoderm inside)

axes / orientation established

Question 6

four types of animal tissue

Answer 6

epithelial
connective
muscle
nervous

Question 7

types of epithelial tissues

Answer 7

single layer: columnar, cuboidal, squamous
+stratified

Question 8

name some cells found in connective tissues

Answer 8

fibroblasts – secrete fibres and other ECM components
adipocytes (fat cells)
chondrocytes (cartilage cells)
osteocytes (bone cells)
mast cells
white blood cells
macrophages
plasma cells

Question 9

layers of skin and types of tissue involved

Answer 9

epidermis = epithelial tissue outside

dermis = tough CT
hypodermis = fattier CT
supplied with blood vessels and nerves

Question 10

two types of liquid connective tissue

Answer 10

blood tissue
lymph

Question 11

what is the ECM of blood CT?

Answer 11

liquid ECM = blood plasma

Question 12

where do the cells in blood come from?

Answer 12

hematopoietic stem cells
which generate various precursors that proliferate + differentiate into mature blood cell types

Question 13

which blood cell types are nucleated?

Answer 13

different types of white blood cell: lymphocytes, eosinophils/basophils/neutrophils, monocytes

RED blood cells lacks nucleus and DNA!

Question 14

name three types of muscle tissue

Answer 14

skeletal
cardia
smooth

Question 15

describe some features of cardiac muscle tissue

Answer 15

striated
intercalated discs !! unique to cardiac muscle
involuntary movement

Question 16

define benign and malignant tumour

Answer 16

benign - cells proliferate in defiance of normal constraints

malignant - cells invade and colonise other territories

Question 17

how do cancers arise?

Answer 17

BOTH genetic and multiple exposures (often over many years) –> changes in DNA –> mutations
carcinogenesis: either due to chemical carcinogen or radiation

Question 18

how do mutations lead to cancer?

Answer 18

alters either:
cell growth
cell proliferation
cell survival (apoptosis)

ie. pathways that regulate cell survival in response to DNA or stress

Question 19

define metastasis

Answer 19

a secondary tumour - malignant cancer spreads to a new site
usually by crossing basal lamina, migrating through CT to blood/lymph to get to new location

Question 20

how do tumours evolve?

Answer 20

repeated rounds of mutation, proliferation and natural selection

each stage of metastasis / migration enhances a single cell’s ability to survive so its progeny become a dominant clone

Question 21

two genes that are important in the development and progression of cancer

Answer 21

oncogenes (cell proliferation) and tumour suppressor genes (usually restrains cell growth and division)

Question 22

what is an oncogene?

Answer 22

a cell that has the potential to become a cancer cell - when activated, promotes cell proliferation

Question 23

why are cancers said to be genetically unstable?

Answer 23

cancers can evolve rapidly – can accumulated genetic changes at an abnormally rapid rate, giving it a selective advantage, allowing accumulation of many mutations