WEEK 4 - TISSUES

Question 1

What are tissues?

Answer 1

Group of cells with similar structure and function.

Question 2

What are the 4 primary types of tissues?

Answer 2

1) Epithelial tissue (epithelium)
2) Connective tissue
3) Muscle tissue
4) Nervous tissue

Question 3

What does epithelial tissues mean?

Answer 3

• Allows body to interact with both its internal and external environments
• “Epi” = upon
• “thelium” = covering or layer of cellular tissue

Question 4

What holds a cell together?

Answer 4

• Tight junctions: Fusion of phospholipid layers (upper end) (seals off intercellular space)
• Desmosomes: Patch of hook-like proteins (resists mechanical stress)
• Gap junctions: Channel between cells made of protein

Question 5

What are epithelial cells?

Answer 5

• Often form sheets
• Lower surface of an epithelium rests on a basement membrane which sits on a top of connective tissue

Question 6

What are the epithelium characteristics?

Answer 6

• Avascular (without blood vessels)
• Receives its nutrients via diffusion from the vascular connective tissue beneath

Question 7

What is simple in terms of cell layers?

Answer 7

• One layer
• Diffusion, osmosis, filtration, absorption, secretion

Question 8

What is stratified in terms of cell layers?

Answer 8

• More than one layer
• Protection from abrasion (friction)

Question 9

What does squamous mean?

Answer 9

Flattened

Question 10

What does cuboidal mean?

Answer 10

Cube-shaped

Question 11

What does columnar mean?

Answer 11

Column-shaped

Question 12

What is simple squamous?

Answer 12

• Generates membranes
• Line and cover organs
• Lines cardiovascular system (endothelium)
• Lines thoracic and abdominal cavities (serosa)

Question 13

What is glandular epithelium?

Answer 13

• Gland
• One or more cells that SECRETE a product

Question 14

What is endocrine gland?

Answer 14

Secretions (hormones) diffuse into blood

Question 15

What is exocrine gland?

Answer 15

Secretions empty into ducts out to surface Milk, sweat, sebum, wax

Question 16

What are the characteristics of connective tissue?

Answer 16

• Vascular (with blood vessels)
• Most abundant, variable tissue
• Connects body tissues
• Supports, strengthens, protects, movement, internal transportation, insulates, fuel source (energy)

Question 17

What is extracellular matrix?

Answer 17

• Connective tissue is composed of extracellular matrix which is a non-living material that separates cells

Question 18

What is ground substance in terms of extracellular matrix?

Answer 18

• Water, adhesion proteins, polysaccharides
• Can be fluid, gel, rubbery, stone-like

Question 19

What is protein fibres in terms of extracellular matrix?

Answer 19

• Collagen, elastic, reticular
• Account for the functional properties of the tissue
• Collagen (triple helix) most abundant protein in body

Question 20

What is mucous membranes (mucosa)?

Answer 20

Lines body openings

Question 21

What are the different types of connective tissues?

Answer 21

• Fibrous - Dense (fibroblasts). Loose (fibroblasts)
• Adipose (adipocytes)
• Blood, bone, cartilage

Question 22

What are Dense connective tissues?

Answer 22

• More fibres than ground matrix
• Dominant fiber is Collagen
• Regular, irregular and elastic
• Strong, rope-like structures such as
  ▪ Tendons — attach muscles to bones (regular)
  ▪ Ligaments — attach bones to bones (regular)
  ▪ Dermis — lower layers of skin (irregular)

Question 23

What are loose connective tissues?

Answer 23

• More ground matrix, less cells and fibres (randomly arranged, spaces for oedema)
• Most widely distributed (packing tissue)
• Position organs, blood vessels, nerves

Question 24

What is adipose tissue?

Answer 24

• Adipocytes accumulate triglycerides
• 90% subcutaneous (fuel, padding, body shape)
• 10% visceral (produces hormones)
• 5% of cells are macrophages

Question 25

What are organs?

Answer 25

• Composed of two or more tissue types working together
• An organ may belong to two or more organ systems

Question 26

What are organ system?

Answer 26

• Group of organs / tissues / cells with a collective function
• 11 (12) organ systems
• Many interrelationships