Tissues

Question 1

Define epithelium

Answer 1

The thin tissue forming the outer layer of a body’s surface and lining the alimentary canal and other hollow structures

Question 2

Describe epithelial tissue

Answer 2

• covers surfaces and separates compartments
• has no contact inhibition
• forms cell-cell and cell-ECM junctions to fill any gaps between cells and cover surfaces effectively

Question 3

Describe cell-cell junctions

Answer 3

• desmosomes (adhering junctions) provide firm anchorage
• tight/occluding junctions seal intracellular spaces
• gap junctions allow for cell-cell communication

Question 4

What structures are found in cell-ECM junctions?

Answer 4

Hemidesmosomes

Question 5

Epithelia have very good

Answer 5

regenerative and adaptive powers

Question 6

Function of epithelia depends on

Answer 6

the cell itself, not the ECM

Question 7

Cilia allow

Answer 7

movement of substances

Question 8

Microvilli allow

Answer 8

absorption

Question 9

Give the three types of simple epithelium and an example of each

Answer 9

• squamous e.g. alveoli and capillaries, thin to allow easy diffusion
• cuboidal e.g. lining of nephrons, perform secretion and absorption/pumping
• columnar e.g. lining digestive tract, move mucus when ciliated

Question 10

Give the three types of stratified epithelium and an example of each

Answer 10

• squamous e.g. epidermis, thick and layers can be sloughed off to allow new growth
• cuboidal e.g. ducts of sweat glands, protection
• columnar e.g. pharynx, protection and secretion

Question 11

Describe the epithelial components of the liver

Answer 11

• hepatocytes
• arranged in rows (or cords) between blood vessels
• multiple functions including secretion
• support epithelial cells line blood vessels and bile ducts

Question 12

Describe the epithelial components of the kidneys

Answer 12

• epithelial cells
• arranged into nephrons
• multiple functions including filtration of blood, partial absorption of filtrate
• support cells line blood vessels and renal pelvis which receives toxic urine

Question 13

Give three consequences of abnormal function of covering and lining epithelia

Answer 13

• over/under proliferation
• over/under secretion
• loss of ciliary beat

Question 14

Define gland

Answer 14

collections of multi or single cellular secretory epithelial cells

Question 15

Give the basic functions of glandular epithelium

Answer 15

Endocrine - secretes into blood e.g. adrenal cortex

Exocrine - secretes to surface e.g. sweat glands

Question 16

Give two consequences of abnormal glandular function

Answer 16

Over production - pituitary giantism

Under production - pituitary dwarfism

Question 17

What fibres are found in connective tissue?

Answer 17

Collagen - makes up to 30% body weight, flexible, inelastic with great tensile strength

Elastic fibres - protein elastin, stretch 1.5x length and return to original shape, microfilaments and amorphous component, found in sheets

Question 18

What ground substances are found in connective tissues?

Answer 18

• proteoglycans
• hyaluronic acid
• glycoproteins

Question 19

What types of cell are found in loose connective tissue?

Answer 19

Fixed cells - fibroblasts, macrophages, adipocytes, mast cells

Transient cells - WBCs

Question 20

Give four consequences of abnormal function of connective tissues

Answer 20

Blood/bone marrow - leukaemia

Loose/dense - loss/abnormal fibers

Cartilage - tear

Bone - osteoporosis