Ch. 3 | cells & tissues

cell parts:

organelle: membrane-bound structure w/in a cell that carries out specific functions
cytoplasm: area btwn plasma membrane & nucleus; contains organelles & cytosol (fluid inside cell)
nucleus: houses genetic material
functions:

1. controls cellular structure
2. directs cellular activities
3. produces ribosomes in nucleoli

plasma membrane: cell's gatekeeper; semi-permeable lipid bilayer
functions: 

1. barrier separating inside & outside of cell
2. controls flow of substances into & out of cell
3. helps identify the cell to other cells 
4. participates in intercellular signaling

centrosomes: consists of centriole pairs

function:

1. plays a role in cell division

ribosomes: made of RNA & proteins 

functions:

1. make new proteins

smooth endoplasmic reticulum: doesn't have ribosomes 

functions:

1. synthesizes fatty acids & steriods
2. inactivates/detoxifies drugs & harmful substances
3. stores & releases calcium ions  

rough endoplasmic reticulum: contains ribosomes on walls 

function:

1. make proteins 

golgi complex: array of flat membrane sacs 

functions:

1. modifies/sorts/packages/transport proteins received from rough ER
2. transfer proteins to their destinations 

mitochondria: folded inner membrane surrounded by smooth outer membrane 

functions:

1. generates ATP/energy 

membranes: transport substances 

2 fluid compartments:

1. intracellular fluid (inside the cell)
2. extracellular fluid (outside the cell); different locations = different names:

      -interstitial fluid: btwn cells w/in a tissue
      -plasma: w/in blood vessels
      -lymph: w/in lymphatic vessels
      -cerebrospinal fluid: surrounding brain & spinal cord

concentration: amount of solute dissolved in a given volume of solvent 

concentration gradient: difference in concentration of substance btwn 2 areas 

types of transport: 

• passive: movement w/o using energy 

1. diffusion- substances move high-->low concentration (down concentration gradient)
2. facilitated- diffusion using a channel/pore/carrier
3. osmosis- diffusion of water 

-hypotonic: solution has lower solute concentration than cytosol = cell swells 

-isotonic: solution has same solute concentration as cytosol = no net movement

-hypertonic: solution has higher solute concentration than cytosol = shrivels up 

• active: energy is used to move substances across a membrane against concentration gradient 

protein synthesis: complex process in which proteins are made 

TRANSCRIPTION:
1. gene on DNA strand is copied into mRNA (messenger RNA)
2. mRNA is transported out of the nucleus & into ribosomes
TRANSLATION: 

3. ribosomes read mRNA so tRNA (transfer RNA) knows which amino acids to bring
4. ribosomes join amino acids together as required by DNA
5. ribosome falls apart & releases newly made protein

cell division functions:

1. cell renewal
2. cell repair
3. cell growth
4. reproduction

types of cell division:

• mitosis: somatic cell division

parts of interphase: (resting phase) 

1. G1- growth phase where proteins are synthesized 

2. S- DNA is replicated

3. G2- another growth phase where proteins are made 

• cytokinesis: cytoplasm division
• meiosis: gamete cell division 

daughter cell: either of the two identical cells that form when a cell divides

tissues: groups of cells working together to perform a specific function 

2 components found in tissue: 

1. cells
2. extracellular matrix (which has 2 components: ground substance & protein fibers)

4 basic types of tissues:

1. epithelial: protection, covers body surfaces, form glands, lines body cavities/hollow organs/ducts

• epithelial cell shapes & layers:

simple:absorption/secretion
stratified: protection

locations:
Simple squamous- blood vessels, lining of heart (diffusion & filtration) 
Simple cuboidal- ovary linings, eye surfaces (secretion & absorption) 
Simple columnar- lining of digestive tract (absorption) 
Stratified squamous- skin (upper layers), lining of vagina, mouth (protects underlying cells) 
Transitional- lining of urinary bladder (specialized) 
Pseudostratified columnar- lines respiratory passageways

2. connective: binds/protects/supports body & organs

locations:

• Areolar – skin (provides strength/elasticity/support)

• Adipose – hypodermis/subcutaneous layer (energy reserve/support/protection)

• Reticular – spleen, lymph nodes (forms framework of organs, binds smooth muscle cells)

• Bone – bones of the skeletal system (mechanical support, blood cell production)

• Blood – blood vessels (transport of substances & gases)

3. muscular: generates force for movement, contracts

locations:

• Skeletal muscle – attached to the skeleton (striated, voluntary)
• Smooth muscle – inside hollow organs (striated, involuntary, intercalated discs)
• Cardiac muscle – located in the heart (not striated, involuntary)

4. nervous: transmit impulses to coordinate activities, receives stimuli

• neurons: specialized cells that are sensitive to various stimuli
• neuroglia: supporting cells that don't generate nerve impulses 

locations:

• Nerve cells – located throughout the body

microscope parts: