Test 1 Flashcards
3 Main Parts of Cell
1) Plasma membrane
2) Nucleus
3) Cytoplasm (Cytosol is the liquid portion of the cytoplasm)
Plasma Membrane Function
- Flexible outer surface
- separates outside and inside of cell
- cellular communication
- regulates what goes in and out of a cell
- selectively permeability
Fluid Mosaic Model
- most lipids easily rotate and move sideways in their own 1/2 of the bilayer
- lipids change places
- membrane fluidity allows the assembly of membrane proteins, movement of membrane components, self-sealing
Function of Membrane Proteins (Peripheral and Integral)
- cell to cell communication
- channels/carriers
Passive Transport
1) Simple diffusion - area of high concentration > lower concentration
2) Facilitated diffusion - channel/carrier mediated w/o expenditure of energy
Osmosis
- net movement of water across plasma membrane
- simple diffusion + water channels (aquaporins)
Primary Active Transport
- uses energy from ATP
- carriers called pumps
- most common: Na+/K+ ATPase
- Function: maintains Na+ and K+ inside the cell
Secondary Active Transport
- energy stored in the Na+ and H+ concentration gradient is used to drive other substances cross the membrane
- symporters & antiporters
Tonicity of Cells
- shrivelled if placed in hypertonic solution
- normal in isotonic
- swollen in hypotonic
Vesicles Transport
- Active transport requires the use of energy in the form of ATP to move molecules in & out of the cell
- Molecules move against their concentration gradient
- Uses integral proteins
Endocytosis
- substances brought into cell
- phagocytosis
- receptor-mediated endocytosis
- pinocytosis
Exocytosis
- cells release materials to surroundings
- all cell carry out exocytosis
- neurons release neurotransmitters, etc.
Cytoskeleton
- Network of protein filaments
- provide structure to the cells and organizes cell content
- help with movement of organelles, chromosomes, and whole cell
- microfilaments (actin), intermediate filaments, microtubules
Mitochondria
•Contains DNA and many enzymes
•Power house of the cells = Produces ATP
•Regular exercise increases the number of mitochondria in
muscle cells, increasing efficiency
Endoplasmic Reticulum
1) Smooth ER - no ribosomes, makes phospholipids for membrane, detoxification, stores calcium
2) Rough ER - contains ribosomes, synthesizes proteins to be exported, modifes new proteins
Ribosome
- organelles composed of proteins and rRNA
- free floating site of protein synthesis
- small and large subunit
Golgi apparatus
- modifies, packages, sorts and transports proteins, synthesizes lysosomes
- proteins comes from ribosome on ER, then to Golgi, then to designated area
Lysosome
-Vesicles with powerful digestive enzymes
Proteasomes
- barrel shaped organelle
- breaks down damaged, unneeded and abnormal proteins
Nucleus
- directs cellular activity
- surrounded by nuclear envelope
- genes, composed of DNA are found here
- nucleolus (produces ribosomes)
Cell Cycle
1) Interphase - G1 phase, S phase, G2 phase
2) Mitotic Phase (prophase, metaphase, anaphase, telophase)
Transcription
- DNA > RNA
- mRNA makes copy of the DNA instructions
- goes to ribosomes, site of protein synthesis
Translation
- RNA > protein
- mRNA goes to ribosome, tRNA brings a.a. to ribosomes
- forms polypeptide chain
Epithelial Tissue Characteristics
- covers all body surfaces
- lines internal passageways
- forms glands, main glandular tissue
- attached to basement membrane
- polar - apical and basal surfaces
- has nerve endings
- cells reproduce rapidly
- avascular
- tightly packed together
Epithelial Tissue Functions
- Physical protection - against abrasions
- Selective permeability - into and out of body
- Secretions - forms glands, secrete mucus
- Sensations - sends stimulus to CNS
Simple squamous
- single layered, most delicate
- absorption/diffusion
- respiratory system, ventral body cavities, circulatory system
Simple cuboidal
- single-layered cube shaped
- provides limited protection, absorption, secretion
Stratified squamous
S K I N
Stratified cuboidal
-fouund along ducts of sweat and mammary glands
Simple columnar
-small intestine, secretion
Stratified columnar
- only superficial cells are columnar
- found by few large excretory ducts
Pseudostratified
- always have cilia
- odd columnar with weird nuclei distance
- nasal cavity, trachae, bronci, reproductive tract
Transitional
- tolerates considerable stretching
- permits expansion and recoil after stretching
- found in the bladder
Connective Tissue Characteristics
Most abundant tissue in your body
Binds structures together
Connect epithelium to the rest of the body (basal lamina)
Provides support, protection, framework, fills space, stores fat,
produces blood cells, fights infections, and helps repair tissue
Composed of scattered cells with intercellular matrix
Most have a good blood supply
Cells can reproduce
Connective Tissue Functions
• Structure: provide and maintain form in the body
• Mechanical: matrix that connects and binds cells and
organs
• Defense: defend the body against infection and other
harmful substances
• Repair: wound healing
• Metabolic: exchange metabolites, nutrients, and waste
products between tissue and circulatory system
Cells in Connective Tissue
- Fibroblasts
- Macrophages
- Adipocytes
- Mesenchymal cells
- mast cells
- lympocytes
- microphages
Fibers in Connective Tissue
- Collagen: tendons, ligaments
- Reticular: interwoven network thin, tough, flexible
- Elastic: branched and wavy, elastin
Loose Connective Tissue
- packing material of the body
- surrounds blood vessels, stores lipids
- areolar, adipose, reticular
Areolar Connective Tissue
- highly vascularized
- highly resilient
Adipose Tissue
- white fat and brown fat
- stores fat, absorbs shocks, slows heat loss (insulation)
Reticular Tissue
- provides support
- complex, three-dimensional network
- supportive fibers (stroma)
- spleen, liver, lymph nodes, and bone marrow
Dense Connective Tissue
- mostly occupied by collagen fibers
- dense regular, dense irregular, elastic
Dense regular tissue
- made up of parallel colllagen fibers with few elastic fibers
- major cell type is fibroblasts
- forms tendons and aponeuroses
Dense irregular tissue
Irregularly arranged collagen fibers w/ some elastic fibers
Major cell type is fibroblasts
Can withstand tension in multiple directions providing structural
strength
Elastic
- between vertebrate of the spinal column, in blood vessel walls
- stabilizes position of vertebrae
Cartilage
Hyaline, Elastic, Fibrous cartilage
Hyaline Cartilage
-Amorphous film matrix w/ an imperceptible network of
collagen fibers
-Supports, reinforces, cushions, and resists compression
Elastin Cartilage
- Similar to hyaline, but contains more elastic fibers
- Maintains its shape and structure while allowing flexibility
Fibrocartilage
-Similar to hyaline cartilage, but less firm, with thick collagen
fibers
-Provides a tense strength and absorbs compression shock
Bone
- Strong (calcified: calcium salt deposits)
- Resists shattering (flexible collagen fibers)
- Support soft tissues and body weight
Fluid Connective Tissue
-Blood and lymph
Muscle Tissue
1) Skeletal - striated, multinucleated, voluntary, contains very large muscle fibers or cells
2) Cadiac - striated, uninucleated, involuntary
3) Smooth - nonstriated, uninucleated, involuntary, blood vessels, bladder
Stem cell
a cell that can self-renewal and differentiate into different cells
Self-renewal
make more identical copies to self
Potency
Totipotent: a cell can differentiate into (almost) any cell
Pluripotent: a cell can differentiate into cells from multiple germ layers
Multipotent: a cell can differentiate into cells from the same germ layer
Germ layer
-the three layers formed early on during embryogenesis
Endoderm: the outer most layer which develops into neural tissue
Mesoderm: the middle layer which develops into bone, fat, and cartilage
Ectoderm: the inner layer which develops into the gut
Types of Transplantation
Autologous transplantation: from the patient
Allogenic transplantation: from an unrelated donor
Syngeneic transplantation: from an identical twin
Xenograft: from an animal
Ideal Stem Cell
- Be able to differentiate into many cell types
- Will be vastly renewable (self-renew)
- Easily accessible
- Non-immunogenic (most likely resulting from being individual-specific)
- Non-tumorigenic
- Safe
Primitive Stem Cells
1) Embryonic Stem Cells (ESCs): most primitive, totipotent
2) Induced Pluripotent Cells : from adult, used via virus
iPSC Benefits and Challenges
- Ability to differentiate into many cell types - From patient = no immune rejection - Easily accessible - Individual-specific i.e. personalized or non-immunogenic - Vastly renewable - Useful for studying mechanisms of disease
- Use of viral vectors for induction
- Low efficiency of reprogramming
- Risk of tumor formation
- Efficient differentiation protocols required
HSC
- Hematopeitic Sttem Cell
- Used for 1) faulty bone marrow, 2) treatment of genetic blood disease 3) chemotherapy failed
- come from bone marrow
MSC
-Mesenchymal Stem Cells is multipotent
a) Readily isolated from patient and expanded in
culture.
b) No evidence of immortalization.
Minimizes potential for tumor formation
c) Can be frozen and used for repeated
administrations
d) Autologous or allogeneic administration.
e) Immunoprivileged
f) Home to damaged tissues
Therapeutic Effects of MSCs
- Proangiogenic Factors
- Promote survival and proliferation of endogenous cells
- Alter inflammatory and immune responses
- Reduce apoptosis
- Transfer of mitochondria
- Cross-talk with injured tissues (Multiple Myeloma)
NSC
- Neural Stem Cell
- typically derived from fetuses or ESCs
Epidermal Stem Cells
- ~5-10% of the total keratinocyte population
- “Label retaining cells” (LRCs)
- High colony-forming ability in culture
- Long term proliferative capability
- Ability to repopulate epidermis after culture
- Found in the center of “epidermal proliferation units”
- Divide upon skin injury
- Adhere strongly to basal lamina ECM, type IV collagen, fibronectin
CSC
- cardiac stem cells
- difficult to get
- originally believed to not exist
- CSC most likely fix everyday wear and tear but don’t do enough after trauma
HSC
-Hepatic Stem cells (liver)
-Source of hepatocytes and
cholangiocytes
-Robust - easy to isolate and
establish primary cultures and
cell lines
-Can be stored and thawed
-Easily transfected for gene
delivery
-Potential application
-Can’t control
differentiation to
hepatoma
EPC
-Endotthelial Progenitor Cells
EPCs are often used in addition to another cell, commonly a stem cell
-Easy to engraft
-Role in tumor growth
–Used when angiogenesis is needed
The function of EPCs are dependent on what environment (niche) it enters into
-Factors that affect mobilization and proliferation of EPC:
-Physiological: Age, Gender (estrogen), Exercise, Embryonal development
-Pathologic: Smoking, Coronary artery disease, Vascular trauma, Myocardial infarction
-Drugs: Statins
-Growth factors: VEGF, G-CSF/GM-CSF, SDF-1, Erythropoietin
- Poor endothelialization usually leads to enhanced vascular disease
Metal and Alloys as Biomaterials
- electrical and thermal conductivity and mechanical properties
- high strength, fatigue resistance, relatively good wear resistance, easy fabrication, easy to sterilize
- high elastic modulus, corrosion, toxicity
Ceramics
- refractory polycrystalline compounds
- inorganic
- highly inert
- hard and brittle
- high compressive strengtth
- electric and thermal insulators
Calcium Hydroxyapatite
-primary structural component of bone
Polymers Advantages and Disadvantages
- Resilient and easy to fabricate
- not strong, deform with time, not always degradable
Metals advantages and Disadvantages
- Stong, tough, ductile
- May corrode, dense, difficult to prepare
Ceramics advantages and disadvantages
- Very biocompatible
- brittle, not resilient
Composites advantages and disadvantages
- strong, tailor made
- difficult to prepare
