Lecture 2: Cells, Tissues, Membranes Flashcards Preview

BMEG 510 - Anatomy > Lecture 2: Cells, Tissues, Membranes > Flashcards

Flashcards in Lecture 2: Cells, Tissues, Membranes Deck (20)
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1

Plasma membrane

- phospholipid bilayer
- polar head, non-polar tails

2

Passive transport mechanisms

- simple diffusion = small, nonpolar solutes, e.g. oxygen
- facilitated diffusion = small, charged or polar solutes, moves with assistance of plasma membrane proteins
- osmosis = passive movement of water through membrane or aquaporin

3

Types of facilitated diffusion

- channel mediated = water filled protein channel specific to one type of ion
- types = leak channel (always open), gated channel (stimulus to open)
- carrier mediated = carrier proteins to move small polar molecules (e.g. simple sugars, amino acids)

4

Active transport mechanisms

- primary = against concentration gradient due to ion pumps
- secondary = moves against gradient due to movement of a second substance down gradient (symport - same direction, antiport - opposite direction)

5

Vesicular transport mechanisms

- exocytosis = cell to interstitial fluid, vesicles from golgi apparatus fuse with membrane
- endocytosis = cell takes contents from outside

6

Types of endocytosis

- phagocytosis = vesicle fuses with lysosome, lysosome breaks down particle
- pinocytosis = membrane folds inward and engulfs fluid
- receptor-mediated = receptors bind with molecules and folds inwards

7

Function of a cell

- separate internal from external environment
- move molecules in and out (i.e. get nutrients, get rid of waste)
- communicate
- integrate into a tissue
- use energy, store energy
- make molecules, transform molecules
- move

8

Elements of a cell

- cytoplasm = water (70-80%), ions
- organelles = proteins (10-20% - structure and function), lipids (insoluble, form membranes), carbohydrates (energy production)
- genetic material = nucleic acids

9

Nucleus

- control centre for cell metabolism and reproduction
- stores genetic information (DNA → encodes genes → instructions for making proteins)

10

Ribosomes

- made in the nucleolus
- form in the cytoplasm
- site of protein synthesis

11

Endoplasmic reticulum

- rough ER (proteins)
- rough → ribosomes
- smooth ER (lipids)

12

Golgi apparatus

- folding and packaging of proteins
- proteins packaged into vesicles
- located next to ER and near cell nucleus

13

Transport vesicles

- transport proteins for cell membrane (receptors, transporters)
- constitutive secretion
- unregulated membrane fusion

14

Secretory vesicles

- proteins released into extracellular space
- regulated → only preceding with a specific stimulus

15

Lysosomes

- analogous to GI system → digestion of metabolites, debris, invades
- contains own plasma membranes
- encloses hydrolytic enzyme mixture (acidic environment can break down nucleic acids, polysaccharides)

16

Mitochondria

- energy production → glucose + oxygen = ATP
- two membranes → inner folded membrane in interior matrix
- increases surface area for oxidative phosphorylation

17

Cytoskeleton

- polymerization at one end, depolymerization at the other end
- provide tracks for vesicles and organelle transport
- microtubules = hollow, support compression
- intermediate → rope-like, flexible, mechanical strength in tension
- microfilaments/actin = mechanical support for maintaining/changing cell shape

18

Types of junctions

- tight junctions = interlocking junctional proteins, impermeable barrier, e.g. sheets of epithelial tissues
- anchoring junctions = bind to adjacent cells through cadherins (e.g. skin, uterus, heart)
- gap junctions = allow ions and small molecules to pass for intercellular communication

19

Extracellular matrix

- structural proteins = collagen (strength), proteoglycans (compliance, shock absorption), elastin (elasticity)
- adhesive proteins = bind matrix together (fibronectin, laminin)
- transmembrane proteins (integrins)

20

Functions of ECM

- structural integrity
- growth factor regulation
- cell-matrix interactions
- proteolytic turnover
- cellular responses