S2) Integrating Cells into Tissues Flashcards Preview

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Flashcards in S2) Integrating Cells into Tissues Deck (21)
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1
Q

How are cells held together in a tissue?

A
  • Cells are held together in a tissue through their attachment to each other (lateral domain)
  • This involves tight junctions, desmosomes and gap junctions
2
Q

What is the basement membrane?

A

The basement membrane is the structural site for overlying cells and underlying connective tissue

3
Q

How do cells attach to the basement membrane?

A

- Hemidesmosomes – found in tissues subject to abrasion, such as skin, epithelium of oral cavity

- Focal adhesions – that anchor intracellular actin filaments to the basement membrane

4
Q

What are integrins?

A

Integrins are transmembrane proteins that function mechanically, by attaching the cell cytoskeleton to the extracellular matrix (ECM), and biochemically, by sensing whether adhesion has occurred.

5
Q

What are the two main functions of integrins?

A
  • Attachment of the cell to the ECM
  • Signal transduction from the ECM to the cell
6
Q

Outline the 3 forms of cell renewal in living body and where it occurs

A
  • Static – CNS, cardiac and skeletal muscle cells
  • Stable – fibroblasts, endothelium, smooth muscle cells
  • Renewing – blood, skin epithelium, gut epithelium
7
Q

Why is cell renewal significant?

A

There is a relationship between cell renewal rate and the propensity to develop cancer

8
Q

Outline the endosymbiotic theory

A
  • Ancestral eukaryotes lived symbiotically with prokaryotes
  • These eukaryotes engulfed the prokaryotes which then evolved to become intracellular mitochondria
  • The mitochondria share DNA, replication patterns, rRNA, RNA with prokaryotes
9
Q

What are the four basic tissue types?

A
  • Epithelial
  • Muscle
  • Nerve
  • Connective tissue
10
Q

What are the 6 specialised connective tissues?

A
  • Cartilage
  • Haemopoietic
  • Lymphatic
  • Adipose
  • Bone
  • Blood
11
Q

What is epithelium?

A

Epithelium: a tissue composed of cells that covers the exterior body surface and lines internal closed cavities and body tubes that communicate with the exterior

12
Q

Identify the 3 different types of apical domain of epithelial cells

A
  • Microvilli
  • Cilia
  • Stereovilli
13
Q

What are microvilli?

A

Microvilli are cytoplasmic processes that extend from the cell surface e.g. intestine and kidney tubule

14
Q

What are cilia?

A

Cilia are motile cytoplasmic processes that can beat in synchrony e.g. tracheobronchial tree and the oviducts

15
Q

What are stereovilli?

A

Stereovilli are particularly long microvilli limited to epididymis and sensory hair cells of the ear

16
Q

What is necrosis?

A

Necrosis is a form of cell injury which results in the premature death of cells in living tissue by autolysis

17
Q

What is apoptosis?

A

Apoptosis is a naturally occurring programmed and targeted cause of cellular death

18
Q

Why is necrosis worse than apoptosis?

A
  • Necrosis is always detrimental and can be fatal
  • Necrosis does not follow the apoptotic signal transduction pathway
  • Necrosis results in the loss of cell membrane integrity and an uncontrolled release of cell contents into the extracellular space
19
Q

Why do necrotic cells swell and burst?

A

Necrotic cells swell and burst because of failure of action of Na, K ATPase

20
Q

Define osmosis

A

Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration until dynamic equilibrium is reached

21
Q

What is oncotic pressure?

A

Oncotic pressure is a form of osmotic pressure exerted by proteins (albumin) in a blood vessel’s plasma that usually tends to pull water into the circulatory system